SETTLEMENT & SLOPE STABILITY ANALYSES

Transcription

1 Appendix A Settlement and Slope Stability Analyses

2 SETTLEMENT & SLOPE STABILITY ANALYSES Saugus RESCO Landfill Saugus, Massachusetts Prepared for: June, 2008 Prepared by: 11 Northeastern Boulevard Salem, NH Project

3 Table of Contents List of Tables...ii List of Attachments...ii 1.0 Introduction General Subsurface Conditions Settlement Analysis General Settlement Model Calculations Static and Seismic Slope Stability Analyses General Method of Analyses Slope Stability Analyses Permanent Displacement Analysis for Seismic Conditions Cross-Section Across Phase III Critical Slope Stability Cross-Section Subsurface Conditions for Analysis Shear Strength of Boston Blue Clay Results of Slope Stability Analyses Static Slope Stability Assuming No Consolidation of BBC Static Slope Stability Assuming Consolidation of BBC Slope Stability under Seismic Conditions Cross-Section Across Phase IV Critical Slope Stability Cross-Section Soil Parameters Results of Static Slope Stability Analysis Results of Seismic Slope Stability Analysis Conclusions and Recommendations Settlement Slope Stability Bibliography N:\projects\119504\2008\VF FEP Docs\Global Stability i

4 List of Tables Table 1 Table 2 Table 3 Table 4 Table 5 Boston Blue Clay Consolidation Calculations Undrained Shear Strength of Boston Blue Clay Under Partial Consolidation Undrained Shear Strength of Boston Blue Clay Under 100% Consolidation Summary of Slope Stability Analyses Results Cross Section Across Phase III Summary of Slope Stability Analyses Results Cross Section Across Phase IV List of Attachments Attachment A Settlement Analysis Attachment B Results of Static and Seismic Slope Stability Analyses Cross-Section Across Phase III B-1 Location of Slope Stability Cross-Section and Test Boring B-2 Results of Static Slope Stability Analysis B-3 Probabilistic Seismic Hazard Based on USGS B-4 Pseudo-Static Slope Stability Analysis to Determine Yield Acceleration B-5 Permanent Displacement Calculations Attachment C Results of Static and Seismic Slope Stability Analyses Cross-Section Across Phase IV C-1 Results of Static Slope Stability Analysis C-2 Results of Seismic Slope Stability Analysis N:\projects\119504\2008\VF FEP Docs\Global Stability ii

5 1.0 Introduction Refuse Energy Systems Company (RESCO), now known as Wheelabrator Saugus, J.V. (Wheelabrator), owns and operates a waste-to-energy plant and the adjacent ash residue disposal site, known as the Saugus RESCO Landfill (Landfill), in Saugus, Massachusetts. The Landfill accepts municipal solid waste (MSW) ash residue from the waste-to-energy plant located adjacent to the Landfill. The currently approved final grading plan for the Landfill consists of a ridge and valley configuration with a maximum elevation of 50 feet mean sea level (MSL) along the ridges. In all, there are five valley lines and six ridge lines. In addition, the Landfill consists of five phases, I through V. Phases I and II have been filled to the currently approved final grading, and Phases III, IV, and V are currently uncapped and either active or dormant covered with a layer of intermediated cover. In accordance with the 2008 Revisions to the Final Engineering Plan (2008 FEP), additional ash residue will be placed within the area between ridges by flattening the cross-slope (this is referred to as the valley fill ). The minimum cross-slope will be decreased from a five percent to a two percent slope, with a side slope of three horizontal to one vertical immediately adjacent to the valley line and in the perimeter areas. The slope along the length of the valley line will be maintained at one percent. The maximum Landfill elevation will remain at 50 feet MSL. This report presents the results of analyses performed by Shaw Environmental, Inc. (Shaw) to determine the impact of the valley fill on landfill settlement and global slope stability of the Landfill Phases III, IV, and V. The settlement analysis was performed using an idealized cross section taken at a critical cross section located within Phases III and IV. The slope stability was analyzed using two cross sections. The first slope stability cross section was taken perpendicular to the western perimeter of Phase III. The second slope stability cross section was taken perpendicular to the northwestern perimeter of Phase IV. N:\projects\119504\2008\VF FEP Docs\Global Stability 1-1

6 2.0 General Subsurface Conditions Boring logs of existing test borings and monitoring wells were used to interpret the general subsurface conditions at the Landfill. No field investigation or laboratory tests were performed as part of this study. A review of these logs shows that the Landfill is underlain by the following strata, starting from the top: Existing municipal solid waste (MSW) ash residue Municipal solid waste A layer of peat (not encountered at all locations) A layer of sand Boston Blue Clay (BBC) Glacial till In general, ash residue deposits vary from 0 to 40 feet in thickness to a maximum elevation of 50 feet MSL overlying the MSW. The bottom of MSW is at an approximate elevation of 0 feet MSL with a maximum thickness of approximately 25 to 30 feet. The thickness of peat varies from 0 to 7 feet. The thickness of sand is between 5 to 10 feet. The thickness of the BBC varies from 20 to 80 feet. The BBC consists of an over-consolidated upper crust which has a medium stiff consistency. The lower part of the BBC is soft, and it is normally consolidated. N:\projects\119504\2008\VF FEP Docs\Global Stability 2-1

7 3.0 Settlement Analysis 3.1 General The purpose of the settlement analysis performed was to determine whether the proposed two percent cross-slope will be adequate to accommodate any differential settlements in the Landfill that may occur in the future. If excessive differential settlement were to occur, surface water runoff to the valleys would be impeded which could result in ponding of surface water. The settlement analysis was performed for an idealized cross-section taken between a critical ridge and valley identified based on the subsurface conditions. 3.2 Settlement Model The MSW ash residue is relatively incompressible due to its cementing properties. Similarly, the settlement of the sand layer can be assumed to be very small because it is dense and its thickness is small. Therefore, the only strata that would contribute to landfill settlement include the following: MSW, peat layer, and the BBC. There are two settlement components associated with all of these three strata: (i) primary compression, and (ii) secondary compression. The potential contribution of each of these two components to differential settlement is discussed below. Primary Compression: The primary compression or primary consolidation of peat and BBC occur when the surcharge load is transferred to the soil skeleton as the excess pore pressure dissipates with time. Although the primary compression mechanism is different for MSW, the state-of-practice is to model its primary compression similar to primary consolidation of peat or clay. The magnitudes of the final value of primary compression of all three strata are proportional to: (i) the thickness of each stratum, and (ii) the magnitude of the surcharge loading. Although the subsurface condition (i.e., thicknesses of the various strata) under the site may vary with location, it is reasonable to assume that such change would be minimal over the length of settlement cross-section taken between any adjacent ridges and valleys because of the relatively short length. Therefore, it can be assumed that the change in subsurface conditions would have very little impact on differential settlement between adjacent ridges and valleys. Accordingly, only the differential settlement due to change in surcharge loading between two points is considered. Also, since the final value of the primary compression (i.e., at 100 percent consolidation) is of interest, the time rate of settlement is not of importance. Secondary Compression: Secondary compression within peat and BBC occur due to an internal rearrangement of the soil skeleton with time, which is independent of surcharge loading. This is a time dependent phenomenon. The secondary compression of MSW occurs due to biological decomposition of the waste with time. Again, the state-of-practice is to model the secondary N:\projects\119504\2008\VF FEP Docs\Global Stability 3-1

8 compression of MSW similar to the secondary consolidation of peat or clay. Also, only the final value of the secondary compression for all three strata is of interest. Since it is not dependent on surcharge loading, the secondary compression can contribute to differential settlement between two adjacent points only if the strata thicknesses between the two points vary. Since it is assumed that the thicknesses of strata are relatively uniform between adjacent ridges and valleys, the contribution of secondary compression to differential settlement should be negligible. It should also be noted that since the MSW is relatively old, it is very likely that almost all of the secondary settlement has already taken place. Accordingly, contribution of differential settlement due to secondary compression has been discounted in the settlement analysis. Based on the above discussion, it can be seen that only the primary compressions of MSW, peat, and BBC due to the difference in surcharge loading between two points need to be computed to estimate the differential settlement between those two points. The critical settlement points are selected along a cross-section taken perpendicular to the critical ridge and valley. 3.3 Calculations The settlement analysis is presented in Attachment A. Based on a review of the existing test boring logs, Shaw developed a typical cross-section along with an idealized subsurface profile. The calculations estimated a slope reduction of approximately 0.24 percent (i.e., post-settlement slope of 1.76 percent) between the critical ridge and valley. A long-term post-settlement slope of 1.76 percent would be adequate to promote surface run-off. N:\projects\119504\2008\VF FEP Docs\Global Stability 3-2

9 4.0 Static and Seismic Slope Stability Analyses 4.1 General In accordance with the 2008 FEP, ash residue placement will continue in Phases III, IV, and V. To analyzed the global slope stability of Phases III, IV, and V, the following two cross sections were used: The first cross section is perpendicular to the western perimeter of Phase III where the thickness of the underlying BBC is inferred to be the greatest within Phases III, IV, and IV. This is referred to as Cross Section Across Phase III in this report. At this location, a significant thickness of MSW and ash residue is already present; therefore, consolidation of the BBC from the existing surcharge loading was considered in the slope stability analysis of this cross section. The second cross section is perpendicular to the northwestern perimeter of Phase IV. This is referred to as Cross Section Across Phase IV in this report. At this location, the thickness of the BBC is relatively small. However, the thickness of the existing ash residue is minimal; therefore, the slope stability analysis for this cross section was performed assuming no consolidation of the BBC. Also, the slurry wall at this location is closest to the toe of the Landfill slope; therefore, sliding block type failure surfaces through the slurry wall were analyzed at this cross section location to determine the potential impact of the Landfill slope on the slurry wall. 4.2 Method of Analyses Slope Stability Analyses The slope stability analysis for the Landfill was performed using the computer program GSTABL7 (Version 2.0) developed by Gregory Geotechnical Software (GGS 2001) in conjunction with the user interface program STEDwin (Version 3.56) developed by Annapolis Engineering Software. The GSTABL7 computer program is an advanced version of the original STABL computer program developed at Purdue University (Purdue 1988). GSTABL7 performs two-dimensional limit equilibrium analysis using the method of slices to compute factors of safety against slope instability based on any of the following four analysis procedures: The modified Bishop method for circular failure surfaces (this method satisfies only moment equilibrium) The simplified Janbu method for circular, random, or sliding block failure surfaces (this method satisfies only force equilibrium) The Spencer method for circular, random, or sliding block failure surfaces (this method satisfies both force and moment equilibrium) N:\projects\119504\2008\VF FEP Docs\Global Stability 4-1

10 The Morgenstern-Price method for circular, random, or sliding block failure surfaces (this method also satisfies both force and moment equilibrium) Because they satisfy both force and moment equilibrium, the factors of safety computed from the Spencer and the Morgenstern-Price methods are more accurate than those obtained from the other two methods. However, the factors of safety computed from the modified Bishop method for circular failure surfaces are typically very close to those computed from Spencer or Morgenstern-Price methods. The simplified Janbu method typically yields conservative factors of safety. The slope stability analyses presented in this report were performed using the modified Bishop method for circular failure surfaces. To be conservative, the simplified Janbu method with the active and passive wedges generated according to the Rankine theory were used for sliding-block failure surfaces Permanent Displacement Analysis for Seismic Conditions The likely magnitude of the seismically-induced paramagnet displacement has been estimated using the simplified charts published by Makdisi and Seed (1978). These charts make use of the ratio of the yield acceleration to the maximum horizontal acceleration (k y /k max ) to provide an estimate of the likely permanent displacement. The yield acceleration value is the horizontal acceleration that results in a pseudo-static factor of safety of 1. The yield acceleration was determined using pseudo-static slope stability analysis using GSTABL. The maximum acceleration is the maximum of the acceleration values averaged over the entire failure surface. 4.3 Cross-Section Across Phase III Critical Slope Stability Cross-Section As noted previously, based on a review of the existing subsurface information in conjunction with the existing and designed ash residue grading at the landfill, a cross-section perpendicular to the western perimeter of Phase III is the most critical for slope stability of the three remaining phases. The location of this critical cross-section is shown in Attachment B-1. The design slope of the ash residue along the landfill perimeter is 3H:1V from elevation 20 feet to elevation 50 feet MSL at this cross-section Subsurface Conditions for Analysis The subsurface conditions at this cross-section location have been determined based on existing test boring logs (Wehran 1989; The IT Group 2000). Test boring PTB-8, monitoring well PMW- 5D, and piezometer PZ-00-4 are located in the vicinity of the selected critical slope stability cross-section; boring logs for these locations are used to approximate the subsurface conditions under the selected slope stability cross section. Based on these logs (see Attachment B-1) and literature from the 1976 MIT test site along I-95 in Saugus, the following thicknesses have been N:\projects\119504\2008\VF FEP Docs\Global Stability 4-2

11 assumed for the various layers/strata underlying the existing ash residue (listed in a descending order): Existing MSW = 20 feet Peat = 7 feet Sand/Silt = 5 feet Medium Boston blue clay = 18 feet Soft Boston blue clay = 60 feet A till or bedrock was assumed below El. 90 (NGVD) Shear Strength of Boston Blue Clay A short-term analysis for the end-of-filling stage using undrained shear strengths (S u ) for the BBC represents the most critical slope stability condition. Therefore, the most critical soil parameter for slope stability is the undrained shear strength of the BBC. To our knowledge, no site-specific shear strength testing of the BBC is available for the Landfill. Therefore, Shaw has used the soil testing information from the Massachusetts Institute of Technology (MIT) research work performed in 1976 for the I-95 embankment in Saugus. This information was provided to Wehran Engineering (now Shaw) by Prof. Charles Ladd of MIT in A method developed by Ladd and Foott (1974), known as SHANSEP (stress history and normalized soil engineering properties), was used to estimate the undrained shear strength of the BBC with depth. Because of the presence of sandy strata both above and below the BBC stratum, it is assumed that the BBC has two-way drainage. Since the S u of the BBC varies with depth, the BBC was subdivided into vertical layers to assign varying S u values with depth. To account for the varying surcharge loading from the varying ash residue height across the cross section, the BBC was also subdivided horizontally. It should be noted that the BBC has been gaining shear strength with time due to its consolidation from the weight of the MSW and the ash residue. To simplify shear strength gain computations, the consolidation due to the MSW and the ash residue have been computed separately and added (i.e., a linear superposition was used). The shear gain due to the MSW has been computed through 2008 assuming that the MSW was placed linearly between 1955 and The degree of consolidation calculations in Table 1 show that the BBC is almost fully consolidated under the weight of the MSW placed prior to The shear strength gain due to weight of the ash residue has been computed assuming that the ash residue was placed linearly between 1985 and The calculations presented in Table 1 show that the consolidation of the BBC varies with depth from 59 to 83 percent. The shear strength calculations are shown in Table 2. This table also shows the SHANSEP equation and parameters used to estimate the S u. The left part of Table 2 shows the estimated original S u of the BBC corresponding to pre-landfill conditions assuming the original ground N:\projects\119504\2008\VF FEP Docs\Global Stability 4-3

12 elevation to be at 0 feet MSL. The estimated S u values in Table 2 have been used in the static slope stability analysis. Table 3 shows the S u values assuming full consolidation of the BBC under both the MSW and the ash residue. These S u values have been used in the seismic slope stability analysis Results of Slope Stability Analyses Static Slope Stability Assuming No Consolidation of BBC The initial slope stability analysis was performed using the original shear strength of the BBC corresponding to the original ground elevation (assumed to be 0 feet MSL) prior to any waste placement at the Landfill. Therefore, this analysis ignores the consolidation and resulting strength gain within the BBC from the waste/ash residue placement above elevation 0 feet MSL. As noted previously, the computed S u values for the BBC are shown in Table 2. The slope stability analysis using these original S u values for the BBC yielded a minimum factor of safety of 1.36, which less than the acceptable factor of safety of 1.5. This shows that consolidation of the BBC should be considered in the slope stability analysis. The slope stability analysis results are included in Attachment B Static Slope Stability Assuming Consolidation of BBC This slope stability analysis accounts for the likely shear strength gain within the BBC from the weight of the MSW and ash residue. The shear strength gain calculations are discussed in Section 4.3; the estimated S u values corresponding to this condition are shown in Table 3. The static slope stability analysis assuming consolidation of the BBC through 2008 yielded a minimum factor of safety 1.6, which is greater than the acceptable value of 1.5. The slope stability analysis results are included in Attachment B Slope Stability under Seismic Conditions General Subtitle D regulations require that landfills located within seismic impact zones 1 be designed to withstand peak ground acceleration (PGA) value having a ten percent probability of exceedance in 250 years (which is equivalent to two percent probability of exceedance in 50 years). Based on the United States Geological Survey (USGS) website, the PGA having a two percent probability of exceedance in 50 years for this site is determined to be 0.16g; the corresponding moment magnitude of the earthquake is 6. Printouts of the USGS based probabilistic seismic hazard are included in Attachment B-3. Since the PGA value is greater than 0.1g, this Landfill is located within a seismic impact zone and, therefore, requires a seismic slope stability analysis. 1 Seismic impact zones are areas where the peak ground acceleration having a 10 percent probability of exceedance 250 years is greater than 0.10g. N:\projects\119504\2008\VF FEP Docs\Global Stability 4-4

13 Because the seismic loading is cyclic in nature (i.e., loading magnitude and direction change rapidly with time), an allowable factor of safety criterion is not appropriate for seismic slope stability. Instead, the state-of-practice is to use the concept of an acceptable permanent displacement. According to the U.S. Environmental Protection Agency (USEPA 1995), 12 inches is considered as the maximum allowable limit of seismically-induced permanent displacement for landfill slopes. Based on Newmark (1965), the potential for permanent displacement exists only if the maximum of the average horizontal accelerations induced within the slope stability cross-section exceeds the yield acceleration. The yield acceleration is the horizontal acceleration that results in a pseudo-static factor of safety of 1, which corresponds to an incipient state of slope movement. Therefore, the first step in the seismic slope stability analysis is to determine the yield acceleration value for the cross-section analyzed. Yield Acceleration An iterative pseudo-static slope stability analysis was performed using the GSTABL7 computer program to determine the minimum yield acceleration for the critical slope stability cross section analyzed. The iterative analysis involved repeating the pseudo-static slope stability analysis by varying the input horizontal acceleration value until the resulting factor of safety is 1. The PGA value corresponding to a ten percent probability on 250 years has a recurrence interval of 2,475 years. Therefore, it is reasonable to assume that the BBC has gained 100 percent consolidation when the site is subjected to the design PGA value. Accordingly, the S u values from Table 3 that correspond to 100 percent consolidation under the MSW and ash residue were assigned to the BBC while determining the yield acceleration. The iterative analysis showed that the minimum yield acceleration value for the critical cross section analyzed is 0.081g. The results of the final iterations of the pseudo-static slope stability analyses are included in Attachment B-4. Since the computed yield acceleration value is less the PGA value (i.e., 0.16g), a permanent displacement analysis was performed as discussed below. Permanent Displacement In the absence of seismic response analysis (e.g., SHAKE) to determine the time history of average accelerations within the critical failure surface, it is assumed that the maximum of the average acceleration values (k max ) within the critical failure surface (corresponding to the yield acceleration value) is equal to the PGA value. This assumption is conservative since the magnitudes of horizontal acceleration values at different points within the failure plane would be different, and all of these values would be less than or equal to the PGA value; therefore, the N:\projects\119504\2008\VF FEP Docs\Global Stability 4-5

14 average accelerations at different time durations (and hence the k max ) would be typically less than the PGA value. The permanent displacement calculations performed using the Makdisi and Seed (1978) chart is presented in Attachment B-5. These calculations estimate a maximum permanent displacement of approximately 4 inches. Since this is less than the maximum allowable limit of 12 inches, it is acceptable. The results of both static and seismic slope stability analyses for this cross-section are summarized in Table Cross-Section Across Phase IV Critical Slope Stability Cross-Section Since the existing ash residue elevations within Phase IV are significantly lower than 50 feet, it is concluded that slope stability along the outer perimeter of Phase IV could be critical, at this stage of the landfill operation. Accordingly, this second cross-section taken perpendicular to the northwestern perimeter of Phase IV (next to Route 107) was analyzed for slope stability. The location of this cross-section is shown in Attachment C-1. The subsurface condition at this cross-section location was interpreted based on the log for test boring PTB-6 (the boring log is included in Attachment C-1) Soil Parameters Again, a short-term analysis for the end-of-filling stage using undrained shear strength for the BBC represents the most critical slope stability condition. Therefore, as noted previously, the critical soil parameter for slope stability is the undrained shear strength of the soft BBC. The shear strength calculations along with the SHANSEP parameters used are presented in Attachment C-1. The initial average undrained shear strength of the BBC at the analyzed cross-section location, assuming no consolidation, is conservatively estimated to be 1,015 pounds per square foot (psf) Results of Static Slope Stability Analysis Slope stability of the Landfill slope with both circular and sliding-block type failure surfaces was analyzed. The sliding-block type failure surface was also used to analyze potential failure surfaces that pass through the slurry wall. As noted previously, a short-term analysis using undrained shear strength for the BBC represents the most critical slope stability condition. To be conservative 2, this analysis was performed 2 It should be noted that the shear strength of the BBC will increase with time due consolidation from the ash to be placed in the future. Therefore, the analyses performed are conservative. N:\projects\119504\2008\VF FEP Docs\Global Stability 4-6

15 assuming the current undrained shear strength for the BBC which is estimated to be 1015 psf. This analysis yielded a static factor of safety of 2.15 for the circular failure mode and 1.87 for the sliding-block type failure mode. A sliding-block failure surface passing through the slurry wall yielded a higher factor of safety of Therefore, all the computed factors of safety values are greater than the acceptable value of 1.5. The results of slope stability analyses for static conditions are included in Attachment C-1. A summary of the results is presented in Table Results of Seismic Slope Stability Analysis The yield acceleration was determined using the GSTABL7 computer program. Again, the estimated original undrained shear strength was assigned to the BBC in this analysis, which is conservative because it ignores consolidation and strength gain within the BBC. The analysis shows a minimum yield acceleration value of 0.151g for a sliding-block type failure mode through the slurry wall. Since this value is very close to the PGA, the anticipated permanent displacement would be very small. A permanent displacement analysis using the Makdisi and Seed (1978) chart estimated a permanent displacement of only 0.1 inches, which is significantly lower than the allowable limit of 12 inches. The GSTAB7 plots and printouts of the pseudo-static slope stability analyses are included in Attachment C-2. The permanent displacement analysis is also presented in Attachment C-2. A summary of the computed yield acceleration values and the estimated permanent displacement is shown in Table 5. It should be noted that these results are conservative because: (i) they ignore the consolidation of the BBC during filling, and (ii) the slope stability analyses were performed using the Janbu method. N:\projects\119504\2008\VF FEP Docs\Global Stability 4-7

16 5.0 Conclusions and Recommendations 5.1 Settlement The settlement analysis discussed herein demonstrates that a minimum slope of two percent over the valley fill areas of the Landfill would be adequate to accommodate future differential settlements. The settlement analysis is a predictive assessment of the anticipated settlement based on idealized subsurface conditions and assumed settlement model and parameters. It is possible that actual subsurface conditions may not be as uniform as inferred from the limited test borings and settlement parameters could vary, which could result in a few localized depressions. Therefore, provisions are included in the Closure and Post-Closure Plan for the Landfill for inspection and re-grading of the final cover if detrimental differential settlements are observed in the field. 5.2 Slope Stability The slope stability analysis for the Landfill shows adequate factors of safety under static conditions for both circular and sliding-block type failure surfaces, including failure surfaces through the slurry wall. The seismic analysis shows that the potential for excessive permanent displacement during the design earthquake does not exist. N:\projects\119504\2008\VF FEP Docs\Global Stability 5-1

17 6.0 Bibliography Bray, J.D., Rathje, E.M., Augello, A.J., and Merry, S.M. (1998). "Simplified Seismic Design Procedure for Geosynthetic-Lined, Solid-Waste Landfills." Geosynthetics International, Vol. 5, Nos Code of Federal Regulations, Title 40, Part 258. Gregory Geotechnical Software (GGS). (2001). GSTABL7 with STEDwin Slope Stability Analysis System, Program Manual, Version 2.0, dated September Kavazanjian, Jr., E., Matasovic, N., Bonaparte, R., and Schmertmann, G.R. (1996). "Evaluation of MSW Properties for Seismic Analysis." Geoenvironment 2000, Geotechnical Special Publication No. 46, pp Ladd, C.C. and Foott, R. (1974). New Design Procedures for Stability of Soft Clays, Journal of the Geotechnical Engineering Division, Proceedings of the American Society of Civil Engineers, Vol. 100, GT 7, July, pp Makdisi, F.I., and H.B. Seed. (1978). Simplified Procedure for Estimating Dam and Embankment Earthquake-Induced Deformations." Journal of the Geotechnical Engineering Division, ASCE, Vol. 104, No. GT7. Newmark, N.M. (1965). "Effects of Earthquakes on Dams and Embankments." Geotechnique, Volume 5, No. 2. Purdue University. (1988). User Guide for PC STABL 5M. Schiffman R.L. (1958). "Field Applications of Soil Consolidation: Time-Dependent Loading and Varying Permeability, Highway Research Board, Bulletin 248. U.S. Environmental Protection Agency (EPA). (1995). RCRA Subtitle D (258) Seismic Design Guidance for Municipal Solid Waste Landfill Facilities by Gregory N. Richardson, Edward Kavazanjian, Jr., and Neven Matasovic, Report No. EPA 600/R-95/051. USGS website: N:\projects\119504\2008\VF FEP Docs\Global Stability 6-1

18 Tables

19 Table 1 Boston Blue Clay Consolidation Calculations Cross Section Across Phase III Saugus RESCO Landfill 1. Consolidation from Existing MSW Based on ash residue filling at 3H:1V to elevation 50 feet MSL Approximate year the MSW filling started = 1955 Approximate year MSW filling ended = 1985 Assuming the waste filling took place linearly t 0 = 30 years Year when percent of consolidation required 2008 t = 53 years Based on the 1999 analysis, Cv for the clay c v = 0.2 ft2/day Total thickness of clay 2H = 78 ft2/day Assuming two-way drainage H = 39 ft T 0 = C v. t 0 /H 2 T 0 = 1.44 T = C v. t/h 2 T = 2.54 T-T 0 = 1.10 Soil Nos. z z/h u p /u 0 (T) u p /u 0 (T-T 0 ) T 0.u/u 0 u/u 0 % Consol. (see Note 1) (See Note 2) (See Note 2) 5, 6, 7, 8, & , 11, 12, 13, & , 16, 17, 18, & Notes: 1. Soil nos. correspond the soil numbering used in the slope stability analysis 2. These value are obtained from Table 2 of "Field Applications of Soil Consolidation: Time-Dependent Loading and Varying Permeability", by Schiffman, R.L. (1958). z = depth u = excess pore pressure 2. Consolidation from Ash Residue Based on ash residue filling at 3H:1V to elevation 50 feet MSL Approximate year the ash filling started = 1985 Year when percent consolidation required = 2008 Assuming the filling to be linear t 0 = t = 23 T =T 0 = C v. t 0 /H 2 T 0 = T = 1.10 u z /u 0 = (z/h) - (0.5)(z/H) 2 Soil Nos. z z/h u z /u 0 u p /u 0 (T) T 0.u/u 0 u/u 0 % Consol. (See Note) 5, 6, 7, 8, & , 11, 12, 13, & , 16, 17, 18, & Note: These value are obtained from Table 2 of "Field Applications of Soil Consolidation: Time-Dependent Loading and Varying Permeability", by Schiffman, R.L. (1958).

20 Table 2 Undrained Shear Strength of Boston Blue Clay Under Partial Consolidation Cross Section Across Phase III Saugus RESCO Landfill Based on ash residue filling at 3H:1V to elevation 50 feet MSL Original ground elevation = 0.0 ft Total unit weight of clay = pcf Ground water elevation = 0.0 ft Unit weight of water = 62.4 pcf Unit weight of MSW = 65.0 pcf Unit weight of ash = pcf σ' vc Consolidation from MSW Consolidation from Ash σ' vc σ' vc + σ' vc Soil No. Soil Elev. Effect. OCR Original S u MSW Ht. MSW Wt. % Consol. Stress Incr. Ash Ht. Ash Wt. % Consol. Stress Incr. Total Stress New Effect. New OCR New S u Stress (see Note 1) (see Note 2) Increase Stress (see Note 3) (ft) (psf) (psf) (ft) (psf) (psf) (ft) (psf) (psf) (psf) (psf) (psf) 1 Ash 2 MSW 3 Peat Silt/Sand 5 Med. BBC Med. BBC Med. BBC Med. BBC Med. BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Notes: 1. Over-consolidation ratio (OCR) based on MIT data from Route I-95 test fill 2. The undrained shear strength (S u ) values for BBC were obtained using the following SHANSEP relationship: 3. The undrained shear strength (Su) values were obtained using the following SHANSEP relationship: Su = ( 0.2)( σ vc)( OCR) S = ( 0.2)( σ + σ )( OCR) u vc vc 0.765

21 Table 3 Undrained Shear Strength of Boston Blue Clay Under 100% Consolidation Cross Section Across Phase III Saugus RESCO Landfill Based on ash residue filling at 3H:1V to elevation 50 feet MSL Original ground elevation = 0.0 ft Total unit weight of clay = pcf Ground water elevation = 0.0 ft Unit weight of water = 62.4 pcf Unit weight of MSW = 65.0 pcf Unit weight of ash = pcf σ' vc Consolidation from MSW Consolidation from Ash σ' vc σ' vc + σ' vc Soil No. Soil Elev. Effect. OCR Original S u MSW Ht. MSW Wt. % Consol. Stress Incr. Ash Ht. Ash Wt. % Consol. Stress Incr. Total Stress New Effect. New OCR New S u Stress (see Note 1) (see Note 2) Increase Stress (see Note 3) (ft) (psf) (psf) (ft) (psf) (psf) (ft) (psf) (psf) (psf) (psf) (psf) 1 Ash 2 MSW 3 Peat Silt/Sand 5 Med. BBC Med. BBC Med. BBC Med. BBC Med. BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Notes: 1. Over-consolidation ratio (OCR) based on MIT data from Route I-95 test fill 2. The undrained shear strength (Su) values for BBC were obtained using the following SHANSEP relationship: 3. The undrained shear strength (Su) values were obtained using the following SHANSEP relationship: Su = ( 0.2)( σ vc)( OCR) S = ( 0.2)( σ + σ )( OCR) u vc vc

22 Analysis Table 4 Summary of Slope Stability Analyses Results Cross Section Across Phase III Saugus RESCO Landfill Consolidation of BBC S u Values from Static Factor of Safety Yield Acceleration Estimated Permanent Displacement Static None From Table Static Yield Acceleration Notes: Partial (see Table 1) BBC = Boston Blue Clay S u = Undrained shear strength (1) These values are acceptable From Table (1) % From Table g 4 inches (1)

23 Slope Stability Run Table 5 Summary of Slope Stability Analyses Results Cross Section Across Phase IV Saugus RESCO Landfill Consolidation of BBC Failure Mode Static Factor of Safety Yield Acceleration Estimated Permanent Displacement 1 None Circular 2.15 (1) 0.201g -- 2 None Block 1.87 (1) 0.154g -- 3 None Block through slurry wall 2.06 (1) 0.151g 0.1 inches (1) Notes: BBC = Boston Blue Clay (1) These values are acceptable

24 N:\projects\119504\2008\VF FEP Docs\Global Stability Attachment A Settlement Analysis

25 325' 376' 376' 51' Elevation 50 A 2% B ' % C Ash Solid Waste Peat Sand/Silt 0.5 Medium Boston Blue Clay 9-10 Soft Boston Blue Clay Figure 1. Idealized Settlement Cross-Section (Not to Scale) Page 1 of 5

26 Required: Determine whether the 2% slope on the final grading will be adequate considering settlement over the long-term Assumptions: - Figure 1 shows an idealized cross-section taken perpendicular to the valley line - The post-settlement slope between Points A and B would be the most critical - The differential settlement between points A and B will determine the post-settlement slope - Assuming the ash and sand to be relatively incompressible, the underlying layers that will undergo settlement are the solid waste, peat, and Boston Blue Clay (BBC) - All three compressible layers have two components of settlement: (i) a primary compression, which is both load and thickness dependent, and (ii) a secondary compression, which is time and thickness dependent (for waste, the secondary compression includes decomposition of waste with time and for BBC it is secondary consolidation) - To simplify the settlement calculations, it is assumed that the thicknesses of the different compressible strata are uniform; therefore, the secondary settlements at both A and B would be the same - Therefore, only the primary compression due to difference in the surcharge loading between A and B would lead to differential settlement - The difference in surcharge loading between A and B is that due to 6.5 feet of ash - Based on the discussion above, only the primary compression of solid waste, peat, and BBC at Point A due to the 6.5 feet difference in ash thickness needs to be computed to determine the slope change between A and B due to differential settlement Page 2 of 5

27 Design Parameters Critical Slope Length: - Distance between Points A and B = 325 ft - Minimum initial slope = 2 % Thicknesses of Various Layers: - Thickness of excess ash at Point A = 6.5 ft - Ash thickness at B = 26.5 ft - Thickness of solid waste = 17 ft - Thickness of peat = 0.5 ft - Thickness of sand/silt = 0.5 ft - Thickness of medium Boston Blue Clay = 9 ft - Thickness of soft Boston Blue Clay = 20 ft Groundwater Table: - Assumed depth to groundwater table = 0 ft Ash Parameters: - Unit weight = 105 pcf Solid Waste Parameters: - Unit weight = 65 pcf - Compression ratio = Number of sublayers used = 3 Peat Parameters: - Unit weight = 100 pcf - Compression ratio = Number of sublayers used = 1 Sand/Silt Parameters: - Unit weight = 120 pcf Medium Boston Blue Clay Parameters: - Unit weight = 110 pcf - Compression ratio = Recompression ratio = Number of sublayers used = 5 Soft Boston Blue Clay Parameters: - Unit weight = 110 pcf - Compression ratio = Recompression ratio = Number of sublayers used = 5 Page 3 of 5

28 Calculations Excess Loading at Point A relative to Point B = psf Excess settlement of solid waste under Point A: Sublayer Sublayer Mid-Depth Total Effective Incremental thickness Elevation Vert. Stress Vert Stress Settlement (ft) (ft) (psf) (psf) inches Cumulative = 5.0 Inches Excess settlement of peat under Point A: Sublayer Sublayer Mid-Depth Total Effective Incremental thickness Elevation Vert. Stress Vert Stress Settlement (ft) (ft) (psf) (psf) inches Cumulative = 0.2 Inches Excess settlement of Medium Boston Blue Clay under Point A: Sublayer Sublayer Mid-Depth Total Effective Past Max. Final Effective Incremental thickness Elevation Vert. Stress Vert. Stress Vert. Stress Vert. Stress Settlement (ft) (ft) (psf) (psf) (psf) (psf) inches Cumulative = 0.1 inches Excess settlement of Soft Boston Blue Clay under Point A: Sublayer Sublayer Mid-Depth Total Effective Incremental thickness Elevation Vert. Stress Vert. Stress Settlement (ft) (ft) (psf) (psf) inches Cumulative = 4.1 inches Differential Settlement between Points A and B = 9.4 inches Slope reduction between Points A and B due to the above differential settlement = 0.24 % Post-Settlement Slope = 1.76 % Page 4 of 5

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33 Attachment B Results of Static and Seismic Slope Stability Analyses Cross-Section Across Phase III N:\projects\119504\2008\VF FEP Docs\Global Stability

34 B-1 Location of Slope Stability Cross-Section and Test Boring N:\projects\119504\2008\VF FEP Docs\Global Stability

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43 N:\projects\119504\2008\VF FEP Docs\Global Stability B-2 Results of Static Slope Stability Analysis

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45 2/21/2008 Page 1 of 11 *** GSTABL7 *** ** GSTABL7 by Garry H. Gregory, P.E. ** ** Original Version 1.0, January 1996; Current Version 2.003, Jun (All Rights Reserved-Unauthorized Use Prohibited) ******************************************************************** SLOPE STABILITY ANALYSIS SYSTEM Modified Bishop, Simplified Janbu, or GLE Method of Slices. (Includes Spencer & Morgenstern-Price Type Analysis) Including Pier/Pile, Reinforcement, Soil Nail, Tieback, Nonlinear Undrained Shear Strength, Curved Phi Envelope, Anisotropic Soil, Fiber-Reinforced Soil, Boundary Loads, Wate Surfaces, Pseudo-Static & Newmark Earthquake, and Applied For ******************************************************************** Analysis Run Date: 2/21/2008 Time of Run: 02:07PM Run By: nk Input Data Filename: C:\GEOTECHNICAL\saugus\2008\Global-Stabil\ Output Filename: C:\GEOTECHNICAL\saugus\2008\Global-Stabil\ Unit System: English Plotted Output Filename: C:\GEOTECHNICAL\saugus\2008\Glob tabil\ PROBLEM DESCRIPTION: RESCO; Ash at 3H:1V to El. 50'; No Conso lidation; Run#S1-Bc-1 BOUNDARY COORDINATES 5 Top Boundaries 24 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type (ft) (ft) Below Bnd C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-1.OUT

46 2/21/2008 Page 2 of Default Y-Origin = 0.00(ft) Default X-Plus Value = 0.00(ft) 1 Default Y-Plus Value = 0.00(ft) ISOTROPIC SOIL PARAMETERS 20 Type(s) of Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No PIEZOMETRIC SURFACE(S) SPECIFIED Unit Weight of Water = (pcf) Piezometric Surface No. 1 Specified by 2 Coordinate Points Pore Pressure Inclination Factor = 0.50 Point X-Water Y-Water A Critical Failure Surface Searching Method, Using A Random Technique For Generating Circular Surfaces, Has Been Specified. C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-1.OUT

47 2/21/2008 Page 3 of Trial Surfaces Have Been Generated. 60 Surface(s) Initiate(s) From Each Of 60 Points Equally Spaced Along The Ground Surface Between X = 0.00(ft) and X = (ft) Each Surface Terminates Between and X = (ft) X = (ft) Unless Further Limitations Were Imposed, The Minimum Elevation At Which A Surface Extends Is Y = 0.00(ft) 15.00(ft) Line Segments Define Each Trial Failure Surface. Following Are Displayed The Ten Most Critical Of The Trial Failure Surfaces Evaluated. They Are Ordered - Most Critical First. * * Safety Factors Are Calculated By The Modified Bishop Method * * Total Number of Trial Surfaces Evaluated = 3600 Statistical Data On All Valid FS Values: FS Max = FS Min = FS Ave = Standard Deviation = Coefficient of Variation = 34.2 Failure Surface Specified By 31 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-1.OUT

48 2/21/2008 Page 4 of Circle Center At X = ; Y = ; and Radius = *** *** Individual data on the 48 slices Water Water Tie Tie Earthquake Force Force Force Force Force Surcharge Slice Width Weight Top Bot Norm Tan Hor Ver Load No. (ft) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-1.OUT

49 2/21/2008 Page 5 of Failure Surface Specified By 31 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** 1 Failure Surface Specified By 32 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-1.OUT

50 2/21/2008 Page 6 of Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 29 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-1.OUT

51 2/21/2008 Page 7 of 11 Circle Center At X = ; Y = ; and Radius = *** *** 1 Failure Surface Specified By 30 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 29 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-1.OUT

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57 2/21/2008 Page 1 of 10 *** GSTABL7 *** ** GSTABL7 by Garry H. Gregory, P.E. ** ** Original Version 1.0, January 1996; Current Version 2.003, Jun (All Rights Reserved-Unauthorized Use Prohibited) ******************************************************************** SLOPE STABILITY ANALYSIS SYSTEM Modified Bishop, Simplified Janbu, or GLE Method of Slices. (Includes Spencer & Morgenstern-Price Type Analysis) Including Pier/Pile, Reinforcement, Soil Nail, Tieback, Nonlinear Undrained Shear Strength, Curved Phi Envelope, Anisotropic Soil, Fiber-Reinforced Soil, Boundary Loads, Wate Surfaces, Pseudo-Static & Newmark Earthquake, and Applied For ******************************************************************** Analysis Run Date: 2/21/2008 Time of Run: 02:10PM Run By: nk Input Data Filename: C:\GEOTECHNICAL\saugus\2008\Global-Stabil\ Output Filename: C:\GEOTECHNICAL\saugus\2008\Global-Stabil\ Unit System: English Plotted Output Filename: C:\GEOTECHNICAL\saugus\2008\Glob tabil\ PROBLEM DESCRIPTION: RESCO; Ash at 3H:1V to El. 50'; With Con solid. through 2008; Run#S1-Bc-2 BOUNDARY COORDINATES 5 Top Boundaries 24 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type (ft) (ft) Below Bnd C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-2.OUT

58 2/21/2008 Page 2 of Default Y-Origin = 0.00(ft) Default X-Plus Value = 0.00(ft) 1 Default Y-Plus Value = 0.00(ft) ISOTROPIC SOIL PARAMETERS 20 Type(s) of Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No PIEZOMETRIC SURFACE(S) SPECIFIED Unit Weight of Water = (pcf) Piezometric Surface No. 1 Specified by 2 Coordinate Points Pore Pressure Inclination Factor = 0.50 Point X-Water Y-Water A Critical Failure Surface Searching Method, Using A Random Technique For Generating Circular Surfaces, Has Been Specified. C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-2.OUT

59 2/21/2008 Page 3 of Trial Surfaces Have Been Generated. 60 Surface(s) Initiate(s) From Each Of 60 Points Equally Spaced Along The Ground Surface Between X = 0.00(ft) and X = (ft) Each Surface Terminates Between and X = (ft) X = (ft) Unless Further Limitations Were Imposed, The Minimum Elevation At Which A Surface Extends Is Y = 0.00(ft) 15.00(ft) Line Segments Define Each Trial Failure Surface. Following Are Displayed The Ten Most Critical Of The Trial Failure Surfaces Evaluated. They Are Ordered - Most Critical First. * * Safety Factors Are Calculated By The Modified Bishop Method * * Total Number of Trial Surfaces Evaluated = 3600 Statistical Data On All Valid FS Values: FS Max = FS Min = FS Ave = Standard Deviation = Coefficient of Variation = 30.5 Failure Surface Specified By 29 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-2.OUT

60 2/21/2008 Page 4 of Circle Center At X = ; Y = ; and Radius = *** *** Individual data on the 44 slices Water Water Tie Tie Earthquake Force Force Force Force Force Surcharge Slice Width Weight Top Bot Norm Tan Hor Ver Load No. (ft) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) Failure Surface Specified By 29 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-2.OUT

61 2/21/2008 Page 5 of Circle Center At X = ; Y = ; and Radius = *** *** 1 Failure Surface Specified By 28 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\s1-bc-2.OUT

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67 Table 1 Boston Blue Clay Consolidation Calculations Cross Section Across Phase III Saugus RESCO Landfill 1. Consolidation from Existing MSW Based on ash residue filling at 3H:1V to elevation 50 feet MSL Approximate year the MSW filling started = 1955 Approximate year MSW filling ended = 1985 Assuming the waste filling took place linearly t 0 = 30 years Year when percent of consolidation required 2008 t = 53 years Based on the 1999 analysis, Cv for the clay c v = 0.2 ft2/day Total thickness of clay 2H = 78 ft2/day Assuming two-way drainage H = 39 ft T 0 = C v. t 0 /H 2 T 0 = 1.44 T = C v. t/h 2 T = 2.54 T-T 0 = 1.10 Soil Nos. z z/h u p /u 0 (T) u p /u 0 (T-T 0 ) T 0.u/u 0 u/u 0 % Consol. (see Note 1) (See Note 2) (See Note 2) 5, 6, 7, 8, & , 11, 12, 13, & , 16, 17, 18, & Notes: 1. Soil nos. correspond the soil numbering used in the slope stability analysis 2. These value are obtained from Table 2 of "Field Applications of Soil Consolidation: Time-Dependent Loading and Varying Permeability", by Schiffman, R.L. (1958). z = depth u = excess pore pressure 2. Consolidation from Ash Residue Based on ash residue filling at 3H:1V to elevation 50 feet MSL Approximate year the ash filling started = 1985 Year when percent consolidation required = 2008 Assuming the filling to be linear t 0 = t = 23 T =T 0 = C v. t 0 /H 2 T 0 = T = 1.10 u z /u 0 = (z/h) - (0.5)(z/H) 2 Soil Nos. z z/h u z /u 0 u p /u 0 (T) T 0.u/u 0 u/u 0 % Consol. (See Note) 5, 6, 7, 8, & , 11, 12, 13, & , 16, 17, 18, & Note: These value are obtained from Table 2 of "Field Applications of Soil Consolidation: Time-Dependent Loading and Varying Permeability", by Schiffman, R.L. (1958).

68 Table 2 Undrained Shear Strength of Boston Blue Clay Under Partial Consolidation Cross Section Across Phase III Saugus RESCO Landfill Based on ash residue filling at 3H:1V to elevation 50 feet MSL Original ground elevation = 0.0 ft Total unit weight of clay = pcf Ground water elevation = 0.0 ft Unit weight of water = 62.4 pcf Unit weight of MSW = 65.0 pcf Unit weight of ash = pcf σ' vc Consolidation from MSW Consolidation from Ash σ' vc σ' vc + σ' vc Soil No. Soil Elev. Effect. OCR Original S u MSW Ht. MSW Wt. % Consol. Stress Incr. Ash Ht. Ash Wt. % Consol. Stress Incr. Total Stress New Effect. New OCR New S u Stress (see Note 1) (see Note 2) Increase Stress (see Note 3) (ft) (psf) (psf) (ft) (psf) (psf) (ft) (psf) (psf) (psf) (psf) (psf) 1 Ash 2 MSW 3 Peat Silt/Sand 5 Med. BBC Med. BBC Med. BBC Med. BBC Med. BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Soft BBC Notes: 1. Over-consolidation ratio (OCR) based on MIT data from Route I-95 test fill 2. The undrained shear strength (S u ) values for BBC were obtained using the following SHANSEP relationship: 3. The undrained shear strength (Su) values were obtained using the following SHANSEP relationship: Su = ( 0.2)( σ vc )( OCR) S = ( 0.2)( σ + σ )( OCR) u vc vc 0.765

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72 N:\projects\119504\2008\VF FEP Docs\Global Stability B-3 Probabilistic Seismic Hazard Based on USGS

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74 3/3/2008 Page 1 of 7 *** Deaggregation of Seismic Hazard for PGA & 2 Periods of Spectral Accel. *** *** Data from U.S.G.S. National Seismic Hazards Mapping Project, 2002 version PSHA Deaggregation. %contributions. site: RESCO long: W., lat: USGS update files and programs. dm=0.2. Site descr:rock Return period: 2475 yrs. Exceedance PGA = g. #Pr[at least one eq with median motion>=pga in 50 yrs]= DIST(KM) MAG(MW) ALL_EPS EPSILON>2 1<EPS<2 0<EPS<1-1<EPS<0-2<EPS<-1 EPS< C:\GEOTECHNICAL\saugus\2008\Global-Stabil\Deaggregation.txt

75 3/3/2008 Page 2 of Summary statistics for above PSHA PGA deaggregation, R=distance, e=epsilon: Mean src-site R= 42.2 km; M= 5.80; eps0= Mean calculated for all so Modal src-site R= 15.2 km; M= 4.80; eps0= from peak (R,M) bin Gridded source distance metrics: Rseis Rrup and Rjb MODE R*= 14.8km; M*= 4.80; EPS.INTERVAL: 0 to 1 sigma % CONTRIB.= Principal sources (faults, subduction, random seismicity having >10% contribut Source Category: % contr. R(km) M epsilon0 (mean values) CEUS gridded seism Individual fault hazard details if contrib.>1%: ********************Central or Eastern U.S. Site ***************************** PSHA Deaggregation. %contributions. ROCK site: RESCO long: d W., lat: USGS update files and programs. Analysis on DaMoYr:04/03/2008 Return period: 2475 yrs s. PSA = g. #Pr[at least one eq with median motion>=psa in 50 yrs]= DIST(km) MAG(Mw) ALL_EPS EPSILON>2 1<EPS<2 0<EPS<1-1<EPS<0-2<EPS<-1 EPS< C:\GEOTECHNICAL\saugus\2008\Global-Stabil\Deaggregation.txt

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78 3/3/2008 Page 5 of Summary statistics for above 1.0s PSA deaggregation, R=distance, e=epsilon: Mean src-site R= km; M= 6.62; eps0= Mean calculated for all so Modal src-site R= 34.9 km; M= 6.21; eps0= from peak (R,M) bin Gridded source distance metrics: Rseis Rrup and Rjb MODE R*= 370.6km; M*= 7.39; EPS.INTERVAL: 1 to 2 sigma % CONTRIB.= Principal sources (faults, subduction, random seismicity having >10% contribut Source Category: % contr. R(km) M epsilon0 (mean values) CEUS gridded seism Individual fault hazard details if contrib.>1%: ********************Central or Eastern U.S. Site ***************************** PSHA Deaggregation. %contributions. ROCK site: RESCO long: d W., lat: USGS update files and programs. Analysis on DaMoYr:04/03/2008 Return period: 2475 yrs s. PSA = g. #Pr[at least one eq with median motion>=psa in 50 yrs]= DIST(km) MAG(Mw) ALL_EPS EPSILON>2 1<EPS<2 0<EPS<1-1<EPS<0-2<EPS<-1 EPS< C:\GEOTECHNICAL\saugus\2008\Global-Stabil\Deaggregation.txt

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80 3/3/2008 Page 7 of Summary statistics for above 0.2s PSA deaggregation, R=distance, e=epsilon: Mean src-site R= 58.0 km; M= 6.00; eps0= Mean calculated for all so Modal src-site R= 14.2 km; M= 4.80; eps0= 0.26 from peak (R,M) bin Gridded source distance metrics: Rseis Rrup and Rjb MODE R*= 17.0km; M*= 4.80; EPS.INTERVAL: 1 to 2 sigma % CONTRIB.= Principal sources (faults, subduction, random seismicity having >10% contribut Source Category: % contr. R(km) M epsilon0 (mean values) CEUS gridded seism Individual fault hazard details if contrib.>1%: ********************Central or Eastern U.S. Site ***************************** C:\GEOTECHNICAL\saugus\2008\Global-Stabil\Deaggregation.txt

81 B-4 Pseudo-Static Slope Stability Analysis to Determine Yield Acceleration N:\projects\119504\2008\VF FEP Docs\Global Stability

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83 2/25/2008 Page 1 of 11 *** GSTABL7 *** ** GSTABL7 by Garry H. Gregory, P.E. ** ** Original Version 1.0, January 1996; Current Version 2.003, Jun (All Rights Reserved-Unauthorized Use Prohibited) ******************************************************************** SLOPE STABILITY ANALYSIS SYSTEM Modified Bishop, Simplified Janbu, or GLE Method of Slices. (Includes Spencer & Morgenstern-Price Type Analysis) Including Pier/Pile, Reinforcement, Soil Nail, Tieback, Nonlinear Undrained Shear Strength, Curved Phi Envelope, Anisotropic Soil, Fiber-Reinforced Soil, Boundary Loads, Wate Surfaces, Pseudo-Static & Newmark Earthquake, and Applied For ******************************************************************** Analysis Run Date: 2/25/2008 Time of Run: 09:31AM Run By: nk Input Data Filename: C:\GEOTECHNICAL\saugus\2008\Global-Stabil\ Output Filename: C:\GEOTECHNICAL\saugus\2008\Global-Stabil\ Unit System: English Plotted Output Filename: C:\GEOTECHNICAL\saugus\2008\Glob tabil\ PROBLEM DESCRIPTION: RESCO; Ash at 3H:1V to El. 50'; With 100 % Consolid; Y-Accel; Run#Y1-Bc-2 BOUNDARY COORDINATES 5 Top Boundaries 24 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type (ft) (ft) Below Bnd C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-2.OUT

84 2/25/2008 Page 2 of Default Y-Origin = 0.00(ft) Default X-Plus Value = 0.00(ft) 1 Default Y-Plus Value = 0.00(ft) ISOTROPIC SOIL PARAMETERS 20 Type(s) of Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No PIEZOMETRIC SURFACE(S) SPECIFIED Unit Weight of Water = (pcf) Piezometric Surface No. 1 Specified by 2 Coordinate Points Pore Pressure Inclination Factor = 0.50 Point X-Water Y-Water Specified Peak Ground Acceleration Coefficient (A) = 0.186(g) Specified Horizontal Earthquake Coefficient (kh) = 0.093(g) Specified Vertical Earthquake Coefficient (kv) = 0.000(g) 1 Specified Seismic Pore-Pressure Factor = C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-2.OUT

85 2/25/2008 Page 3 of 11 A Critical Failure Surface Searching Method, Using A Random Technique For Generating Circular Surfaces, Has Been Specified Trial Surfaces Have Been Generated. 60 Surface(s) Initiate(s) From Each Of 60 Points Equally Spaced Along The Ground Surface Between X = 0.00(ft) and X = (ft) Each Surface Terminates Between and X = (ft) X = (ft) Unless Further Limitations Were Imposed, The Minimum Elevation At Which A Surface Extends Is Y = 0.00(ft) 15.00(ft) Line Segments Define Each Trial Failure Surface. Following Are Displayed The Ten Most Critical Of The Trial Failure Surfaces Evaluated. They Are Ordered - Most Critical First. * * Safety Factors Are Calculated By The Modified Bishop Method * * Total Number of Trial Surfaces Evaluated = 3600 Statistical Data On All Valid FS Values: FS Max = FS Min = FS Ave = Standard Deviation = Coefficient of Variation = 27.5 Failure Surface Specified By 29 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-2.OUT

86 2/25/2008 Page 4 of Circle Center At X = ; Y = ; and Radius = *** *** Individual data on the 44 slices Water Water Tie Tie Earthquake Force Force Force Force Force Surcharge Slice Width Weight Top Bot Norm Tan Hor Ver Load No. (ft) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-2.OUT

87 2/25/2008 Page 5 of Failure Surface Specified By 29 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** 1 Failure Surface Specified By 30 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-2.OUT

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89 2/25/2008 Page 7 of 11 *** *** 1 Failure Surface Specified By 31 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 28 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-2.OUT

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95 2/25/2008 Page 1 of 12 *** GSTABL7 *** ** GSTABL7 by Garry H. Gregory, P.E. ** ** Original Version 1.0, January 1996; Current Version 2.003, Jun (All Rights Reserved-Unauthorized Use Prohibited) ******************************************************************** SLOPE STABILITY ANALYSIS SYSTEM Modified Bishop, Simplified Janbu, or GLE Method of Slices. (Includes Spencer & Morgenstern-Price Type Analysis) Including Pier/Pile, Reinforcement, Soil Nail, Tieback, Nonlinear Undrained Shear Strength, Curved Phi Envelope, Anisotropic Soil, Fiber-Reinforced Soil, Boundary Loads, Wate Surfaces, Pseudo-Static & Newmark Earthquake, and Applied For ******************************************************************** Analysis Run Date: 2/25/2008 Time of Run: 09:31AM Run By: nk Input Data Filename: C:\GEOTECHNICAL\saugus\2008\Global-Stabil\ Output Filename: C:\GEOTECHNICAL\saugus\2008\Global-Stabil\ Unit System: English Plotted Output Filename: C:\GEOTECHNICAL\saugus\2008\Glob tabil\ PROBLEM DESCRIPTION: RESCO; Ash at 3H:1V to El. 50'; With 100 % Consolid; Y-Accel; Run#Y1-Bc-r2 BOUNDARY COORDINATES 5 Top Boundaries 24 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type (ft) (ft) Below Bnd C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-r2.OUT

96 2/25/2008 Page 2 of Default Y-Origin = 0.00(ft) Default X-Plus Value = 0.00(ft) 1 Default Y-Plus Value = 0.00(ft) ISOTROPIC SOIL PARAMETERS 20 Type(s) of Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No PIEZOMETRIC SURFACE(S) SPECIFIED Unit Weight of Water = (pcf) Piezometric Surface No. 1 Specified by 2 Coordinate Points Pore Pressure Inclination Factor = 0.50 Point X-Water Y-Water Specified Peak Ground Acceleration Coefficient (A) = 0.162(g) Specified Horizontal Earthquake Coefficient (kh) = 0.081(g) Specified Vertical Earthquake Coefficient (kv) = 0.000(g) 1 Specified Seismic Pore-Pressure Factor = C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-r2.OUT

97 2/25/2008 Page 3 of 12 A Critical Failure Surface Searching Method, Using A Random Technique For Generating Circular Surfaces, Has Been Specified Trial Surfaces Have Been Generated. 60 Surface(s) Initiate(s) From Each Of 60 Points Equally Spaced Along The Ground Surface Between X = 0.00(ft) and X = (ft) Each Surface Terminates Between and X = (ft) X = (ft) Unless Further Limitations Were Imposed, The Minimum Elevation At Which A Surface Extends Is Y = 0.00(ft) 15.00(ft) Line Segments Define Each Trial Failure Surface. Following Are Displayed The Ten Most Critical Of The Trial Failure Surfaces Evaluated. They Are Ordered - Most Critical First. * * Safety Factors Are Calculated By The Modified Bishop Method * * Total Number of Trial Surfaces Evaluated = 3600 Statistical Data On All Valid FS Values: FS Max = FS Min = FS Ave = Standard Deviation = Coefficient of Variation = 35.3 Failure Surface Specified By 41 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-r2.OUT

98 2/25/2008 Page 4 of Circle Center At X = ; Y = ; and Radius = *** *** Individual data on the 58 slices Water Water Tie Tie Earthquake Force Force Force Force Force Surcharge Slice Width Weight Top Bot Norm Tan Hor Ver Load No. (ft) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-r2.OUT

99 2/25/2008 Page 5 of Failure Surface Specified By 39 Coordinate Points C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-r2.OUT

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106 2/25/2008 Page 12 of 12 *** *** Failure Surface Specified By 38 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** **** END OF GSTABL7 OUTPUT **** C:\GEOTECHNICAL\saugus\2008\Global-Stabil\y1-bc-r2.OUT

107 N:\projects\119504\2008\VF FEP Docs\Global Stability B-5 Permanent Displacement Calculations

108 Estimation of Seismically-Induced Permanent Displacement Seismic Slope Stability of Cross Section Across Phase III Saugus RESCO Landfill Based on USGS (2002) seismic hazard mapping, the peak ground acceleration (PGA) having a10% probability of exceedance in 250 years (this is equivalent to 2% probability in 50 years) = 0.16g Mean earthquake magnitude (M) = 6.0 Based on pseudo-static slope stability analysis, the yield acceleration (k y ) = 0.081g Conservatively, assume that the maximum acceleration within the critical slope failure surface (averaged spatially) is equal to the PGA; i.e., k max = 0.081g Therefore, k y /k max = 0.081g/0.16g = 0.50 From the Makdisi and Seed (1978) chart shown below, for an earthquake magnitude of 6 and k y /k max = 0.5, the likely maximum permanent displacement, (U max ) 10 cm 4 inches U max 10 cm 0.5

109 Attachment C Results of Static and Seismic Slope Stability Analyses Cross-Section Across Phase IV N:\projects\119504\2008\VF FEP Docs\Global Stability

110 N:\projects\119504\2008\VF FEP Docs\Global Stability C-1 Results of Static Slope Stability Analysis

111 # FS a 2.15 b 2.16 c 2.16 d 2.16 e 2.16 f 2.17 g 2.17 h 2.17 i 2.18 j 2.19 Soil Desc. New-Ash Old-Ash MSW SandSilt Med-BBC Till SluryWal RESCO; Valley Fill Stability; Section A-A'; Short-Term; Static; Circle c:\geotechnical\saugus\2008\revised 2006 stabil\a-stat-bc1.pl2 Run By: nk 3/12/ :04AM Soil Type No Total Unit Wt. (pcf) Saturated Unit Wt. (pcf) Cohesion Intercept (psf) Friction Angle (deg) Piez. Surface No. W1 W1 W1 W1 W1 W1 W d b a h j c f g i e GSTABL7 v.2 FSmin=2.15 Safety Factors Are Calculated By The Modified Bishop Method

112 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-bc1.OUT Page 1 *** GSTABL7 *** ** GSTABL7 by Garry H. Gregory, P.E. ** ** Original Version 1.0, January 1996; Current Version 2.003, June 2002 ** (All Rights Reserved-Unauthorized Use Prohibited) ********************************************************************************* SLOPE STABILITY ANALYSIS SYSTEM Modified Bishop, Simplified Janbu, or GLE Method of Slices. (Includes Spencer & Morgenstern-Price Type Analysis) Including Pier/Pile, Reinforcement, Soil Nail, Tieback, Nonlinear Undrained Shear Strength, Curved Phi Envelope, Anisotropic Soil, Fiber-Reinforced Soil, Boundary Loads, Water Surfaces, Pseudo-Static & Newmark Earthquake, and Applied Forces. ********************************************************************************* Analysis Run Date: 3/12/2008 Time of Run: 10:04AM Run By: nk Input Data Filename: C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-bc1.i n Output Filename: C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-bc1.O UT Unit System: English Plotted Output Filename: C:\GEOTECHNICAL\saugus\2008\Revi2006 Stabil\a-stat-bc1.PLT PROBLEM DESCRIPTION: RESCO; Valley Fill Stability; Section A- A'; Short-Term; Static; Circle BOUNDARY COORDINATES 8 Top Boundaries 22 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type (ft) (ft) Below Bnd User Specified Y-Origin = (ft) Default X-Plus Value = 0.00(ft) Default Y-Plus Value = 0.00(ft) ISOTROPIC SOIL PARAMETERS 7 Type(s) of Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No A Critical Failure Surface Searching Method, Using A Random Technique For Generating Circular Surfaces, Has Been Specified Trial Surfaces Have Been Generated.

113 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-bc1.OUT Page 2 40 Surface(s) Initiate(s) From Each Of 40 Points Equally Spaced Along The Ground Surface Between X = 0.00(ft) and X = 60.00(ft) Each Surface Terminates Between X = (ft) and X = (ft) Unless Further Limitations Were Imposed, The Minimum Elevation At Which A Surface Extends Is Y = 0.00(ft) 20.00(ft) Line Segments Define Each Trial Failure Surface. Following Are Displayed The Ten Most Critical Of The Trial Failure Surfaces Evaluated. They Are Ordered - Most Critical First. * * Safety Factors Are Calculated By The Modified Bishop Method * * Total Number of Trial Surfaces Evaluated = 1600 Statistical Data On All Valid FS Values: FS Max = FS Min = FS Ave = Standard Deviation = Coefficient of Variation = % Failure Surface Specified By 14 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Individual data on the 25 slices Water Water Tie Tie Earthquake Force Force Force Force Force Surcharge Slice Width Weight Top Bot Norm Tan Hor Ver Load No. (ft) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) Failure Surface Specified By 14 Coordinate Points

114 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-bc1.OUT Page Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 14 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 14 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 15 Coordinate Points

115 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-bc1.OUT Page Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 14 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 15 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 14 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 15 Coordinate Points

116 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-bc1.OUT Page Circle Center At X = ; Y = ; and Radius = *** *** Failure Surface Specified By 13 Coordinate Points Circle Center At X = ; Y = ; and Radius = *** *** **** END OF GSTABL7 OUTPUT ****

117 # FS a 1.87 b 1.87 c 1.87 d 1.87 e 1.88 f 1.88 g 1.89 h 1.89 i 1.89 j 1.89 Soil Desc. New-Ash Old-Ash MSW SandSilt Med-BBC Till SluryWal Soil Type No RESCO; Valley Fill Stability; Section A-A'; Short-Term; Static; Block c:\geotechnical\saugus\2008\revised 2006 stabil\a-stat-sb1.pl2 Run By: nk 3/12/ :04AM Total Unit Wt. (pcf) Saturated Unit Wt. (pcf) Cohesion Intercept (psf) Friction Angle (deg) Piez. Surface No. W1 W1 W1 W1 W1 W1 W gh ij a cd b ef GSTABL7 v.2 FSmin=1.87 Safety Factors Are Calculated By The Simplified Janbu Method

118 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb1.OUT Page 1 *** GSTABL7 *** ** GSTABL7 by Garry H. Gregory, P.E. ** ** Original Version 1.0, January 1996; Current Version 2.003, June 2002 ** (All Rights Reserved-Unauthorized Use Prohibited) ********************************************************************************* SLOPE STABILITY ANALYSIS SYSTEM Modified Bishop, Simplified Janbu, or GLE Method of Slices. (Includes Spencer & Morgenstern-Price Type Analysis) Including Pier/Pile, Reinforcement, Soil Nail, Tieback, Nonlinear Undrained Shear Strength, Curved Phi Envelope, Anisotropic Soil, Fiber-Reinforced Soil, Boundary Loads, Water Surfaces, Pseudo-Static & Newmark Earthquake, and Applied Forces. ********************************************************************************* Analysis Run Date: 3/12/2008 Time of Run: 10:04AM Run By: nk Input Data Filename: C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb1.i n Output Filename: C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb1.O UT Unit System: English Plotted Output Filename: C:\GEOTECHNICAL\saugus\2008\Revi2006 Stabil\a-stat-sb1.PLT PROBLEM DESCRIPTION: RESCO; Valley Fill Stability; Section A- A'; Short-Term; Static; Block BOUNDARY COORDINATES 8 Top Boundaries 22 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type (ft) (ft) Below Bnd User Specified Y-Origin = (ft) Default X-Plus Value = 0.00(ft) Default Y-Plus Value = 0.00(ft) ISOTROPIC SOIL PARAMETERS 7 Type(s) of Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No A Critical Failure Surface Searching Method, Using A Random Technique For Generating Sliding Block Surfaces, Has Been Specified.

119 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb1.OUT Page 2 The Active And Passive Portions Of The Sliding Surfaces Are Generated According To The Rankine Theory Trial Surfaces Have Been Generated. 2 Boxes Specified For Generation Of Central Block Base Length Of Line Segments For Active And Passive Portions Of Sliding Block Is 20.0 Box X-Left Y-Left X-Right Y-Right Height (ft) (ft) (ft) Following Are Displayed The Ten Most Critical Of The Trial Failure Surfaces Evaluated. They Are Ordered - Most Critical First. * * Safety Factors Are Calculated By The Simplified Janbu Method * * Total Number of Trial Surfaces Evaluated = 2000 Statistical Data On All Valid FS Values: FS Max = FS Min = FS Ave = Standard Deviation = Coefficient of Variation = 7.79 % Failure Surface Specified By 15 Coordinate Points *** *** Individual data on the 20 slices Water Water Tie Tie Earthquake Force Force Force Force Force Surcharge Slice Width Weight Top Bot Norm Tan Hor Ver Load No. (ft) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) Failure Surface Specified By 15 Coordinate Points

120 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb1.OUT Page *** *** Failure Surface Specified By 14 Coordinate Points *** *** Failure Surface Specified By 14 Coordinate Points *** *** Failure Surface Specified By 15 Coordinate Points

121 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb1.OUT Page 4 *** *** Failure Surface Specified By 15 Coordinate Points *** *** Failure Surface Specified By 15 Coordinate Points *** *** Failure Surface Specified By 15 Coordinate Points *** *** Failure Surface Specified By 14 Coordinate Points

122 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb1.OUT Page *** *** Failure Surface Specified By 14 Coordinate Points *** *** **** END OF GSTABL7 OUTPUT ****

123 # FS a 2.06 b 2.06 c 2.06 d 2.06 e 2.14 f 2.14 g 2.14 h 2.14 i 2.16 j 2.16 RESCO; Valley Fill Stability; Section A-A'; Short-Term; Static; Block; SluryWal c:\geotechnical\saugus\2008\revised 2006 stabil\a-stat-sb2.pl2 Run By: nk 3/12/ :04AM Soil Desc. New-Ash Old-Ash MSW SandSilt Med-BBC Till SluryWal Soil Type No Total Unit Wt. (pcf) Saturated Unit Wt. (pcf) Cohesion Intercept (psf) Friction Angle (deg) Piez. Surface No. W1 W1 W1 W1 W1 W1 W efgh a ij bcd GSTABL7 v.2 FSmin=2.06 Safety Factors Are Calculated By The Simplified Janbu Method

124 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb2.OUT Page 1 *** GSTABL7 *** ** GSTABL7 by Garry H. Gregory, P.E. ** ** Original Version 1.0, January 1996; Current Version 2.003, June 2002 ** (All Rights Reserved-Unauthorized Use Prohibited) ********************************************************************************* SLOPE STABILITY ANALYSIS SYSTEM Modified Bishop, Simplified Janbu, or GLE Method of Slices. (Includes Spencer & Morgenstern-Price Type Analysis) Including Pier/Pile, Reinforcement, Soil Nail, Tieback, Nonlinear Undrained Shear Strength, Curved Phi Envelope, Anisotropic Soil, Fiber-Reinforced Soil, Boundary Loads, Water Surfaces, Pseudo-Static & Newmark Earthquake, and Applied Forces. ********************************************************************************* Analysis Run Date: 3/12/2008 Time of Run: 10:04AM Run By: nk Input Data Filename: C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb2.i n Output Filename: C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb2.O UT Unit System: English Plotted Output Filename: C:\GEOTECHNICAL\saugus\2008\Revi2006 Stabil\a-stat-sb2.PLT PROBLEM DESCRIPTION: RESCO; Valley Fill Stability; Section A- A'; Short-Term; Static; Block; SluryWal BOUNDARY COORDINATES 8 Top Boundaries 22 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type (ft) (ft) Below Bnd User Specified Y-Origin = (ft) Default X-Plus Value = 0.00(ft) Default Y-Plus Value = 0.00(ft) ISOTROPIC SOIL PARAMETERS 7 Type(s) of Soil Soil Total Saturated Cohesion Friction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No A Critical Failure Surface Searching Method, Using A Random Technique For Generating Sliding Block Surfaces, Has Been Specified.

125 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb2.OUT Page 2 The Active And Passive Portions Of The Sliding Surfaces Are Generated According To The Rankine Theory Trial Surfaces Have Been Generated. 4 Boxes Specified For Generation Of Central Block Base Length Of Line Segments For Active And Passive Portions Of Sliding Block Is 15.0 Box X-Left Y-Left X-Right Y-Right Height (ft) (ft) (ft) Following Are Displayed The Ten Most Critical Of The Trial Failure Surfaces Evaluated. They Are Ordered - Most Critical First. * * Safety Factors Are Calculated By The Simplified Janbu Method * * Total Number of Trial Surfaces Evaluated = 2000 Statistical Data On All Valid FS Values: FS Max = FS Min = FS Ave = Standard Deviation = Coefficient of Variation = % Failure Surface Specified By 15 Coordinate Points *** *** Individual data on the 24 slices Water Water Tie Tie Earthquake Force Force Force Force Force Surcharge Slice Width Weight Top Bot Norm Tan Hor Ver Load No. (ft) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) Failure Surface Specified By 15 Coordinate Points

126 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb2.OUT Page *** *** Failure Surface Specified By 15 Coordinate Points *** *** Failure Surface Specified By 15 Coordinate Points *** *** Failure Surface Specified By 15 Coordinate Points

127 C:\GEOTECHNICAL\saugus\2008\Revised 2006 Stabil\a-stat-sb2.OUT Page *** *** Failure Surface Specified By 15 Coordinate Points *** *** Failure Surface Specified By 15 Coordinate Points *** *** Failure Surface Specified By 15 Coordinate Points *** *** Failure Surface Specified By 15 Coordinate Points

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129