Design and verification of portable direct shear tester with application to remolded colluvium geomaterials

Transcription

1 Joural of Rock Mechaic ad Geotechical Egieerig., (): 6 Deig ad verificatio of portable direct hear teter with applicatio to remolded colluvium geomaterial K. J. Shou, Y. W. Li Departmet of Civil Egieerig, Natioal Chug-Hig Uiverity, Taichug, Taiwa 7, Chia Received Jauary ; received i revied form Jue ; accepted July Abtract: The mechaical propertie of colluvium trogly gover the tability of colluvial lope, ad they are eetial for the related aalyi ad deig. Neverthele, their meauremet i ot eay o accout of heterogeeity i property ad difficulty of amplig. Thi tudy attempted to evaluate the hear tregth of remolded colluvium by mea of a imple direct hear tet i the field. A portable direct hear teter wa deiged to overcome the icoveiece ad expeivee of the covetioal large-cale i-itu direct hear tet. It ca be eaily aembled ad applied for the imple field direct hear tet. For calibratio, the reult of the portable direct hear teter were compared with the reult of the laboratory direct hear teter for four differet type of oil ample, i.e. tadard ad, late debri, areaceou hale debri ad mixture of gravel ad ad. Correlatio formula were etablihed baed o the calibratio, eablig the portable direct hear teter to meaure ad etimate the hear tregth of remolded colluvium i field. Thi tudy primarily focue o the colluvium i Cetral Taiwa, icludig the lateritic Dadu Terrace ad the areaceou hale of Taipig-Wufeg mout. The portable direct hear teter wa applied to ite elected i thee area, ad the reult were further aalyzed ad dicued. Key word: direct hear tet; portable direct hear teter; imple field direct hear tet; colluvial lope Itroductio A a reult of iteive impact of earthquake ad heavy rai, ladlide frequetly occur i Cetral Weter Taiwa. The ladlide could be either ewly iitiated or reactivated, but the geeratio of colluvial lope i ievitable. Therefore, the tability of lope characterized by colluvium i alway a major challege to egieer ad govermet authoritie. For the aalyi ad deig of a colluvial lope, the hear tregth of compoig colluvium i oe of the mot importat characteritic (Hamel ad Flit, 97; Skempto, 98; Fell et al., ; Karikari-Yeboah ad Gyai-Agyei, ; Stark et al., ). The mot commo method of meaurig hear tregth iclude the laboratory direct hear tet ad triaxial tet. But thoe laboratory tet eed field amplig which might ot be eay for the geomaterial like colluvium. For a direct hear tet, cale effect of the hear box ca be critical to tet reult, ad it i Doi:.7/SP.J...6 Correpodig author. Tel: ext. ; kjhou@drago.chu.edu.tw alo affected by relative deity ad type of geomaterial (Cerato ad Luteegger, 6). I geeral, larger hear boxe ad careful ample preparatio are the key factor for a ucceful direct hear tet. To avoid the diturbace of amplig, the large-cale i-itu direct hear tet i a good alterative, but it i highly time-coumig ad expeive. It require heavy-duty machierie to prepare ad perform the tet, which i ot eay epecially i teep terrai ad colluvial lope with limited tetig pace (Maral, 969; Skempto, 98; Matuoka ad Liu, 998; Kakuo et al., ; Matuoka et al., ; ASTM D8-, ; Liu et al., ; Yu et al., 6). To overcome the above diadvatage, thi tudy deiged a portable direct hear teter to tackle the icoveiece of the large-cale i-itu direct hear tet. The major differece betwee thee two method i the amout of effort required to perform a tet. For the portable direct hear teter, it take oly about miute to aemble or diaemble the teter, miute to tet a colluvium ample; therefore it i more efficiet ad le expeive. It wa deiged baed o the mechaim that upper hear box lide upo the lower hear box a the carryig platform wa tilted (Lope et al., ; Briaco et al., ; Narejo, ).

2 K. J. Shou et al. / J Rock Mech Geotech Eg., (): 6 7 Formula were etablihed to correlate iteral frictio agle meaured by laboratory direct hear teter ad the imple field direct hear teter, eablig the portable direct hear teter to accurately meaure the hear tregth of remolded colluvium o ite. Methodology The Weter Foothill of Taiwa comprie the Muha, Guichuli, Chihui, Chola, ad Toukaha edimetary formatio. Except Toukaha formatio, thoe formatio are maily compoed of areaceou hale. Thi tudy focue o the middle ectio of Weter Foothill, icludig Houli Terrace, Dadu Terrace, ad Taipig-Wufeg piedmot area (Cetral Geology Survey, ). A a depoit of debri traported from upper lope face by gravity, colluvium geerally poee the propertie characterized by weak cemetatio, high poroity ad low tregth. Therefore, it i more vulerable to huma activity, earthquake ad heavy rai, ad thi characteritic cotribute to the ladlide-proe behavior of colluvium-ditributed area. Thi behavior wa widely oberved i Cetral Weter Taiwa becaue a tremedou umber of ladlide were iduced by the 999 Chi-Chi earthquake (Li et al., ; Che, ). Thi tudy aim to develop a portable direct hear teter for the tetig of colluvial geomaterial. I additio, the portable direct hear teter oly require limited tetig pace, i.e. approximately. m by. m, ad that make the developed teter more applicable to colluvial lope. The developed teter wa calibrated before applied to the colluvial lope i Cetral Weter Taiwa. Thi tudy comprie two major part decribed a follow.. Calibratio of the portable direct hear teter For calibratio, the tet reult from the developed teter were compared with thoe obtaied from other laboratory direct hear teter, ad correlatio formula were etablihed ubequetly. To ivetigate the robute of the teter, thi tudy adopted four differet type of colluvium-like ample, icludig tadard ad, mixture of % gravel ad % ad, late debri ad areaceou hale debri. The liear regreio method were applied to correlatig the reult of the portable direct hear teter ad thoe of laboratory direct hear teter. The laboratory direct hear teter applied i thi tudy are the mall direct hear teter (with 6. mm cylidrical hear box) for tadard ad, ad the large-cale direct hear teter (with cm by cm rectagular hear box) for the other three ample.. Applicatio of the portable direct hear teter Aerial photo of Houli Terrace, Dadu Terrace, ad Taipig-Wufeg piedmot area were reviewed to fid potetial ditributio of colluvial lope. It wa followed by field ivetigatio to cofirm the colluvium ditributio ad collect variou lope characteritic. There are two type of colluvium i the tudy area, i.e. lateritic colluvium ad areaceou hale colluvium. I order to obtai the repreetative hear tregth of thoe colluvium material, tet ite repreetig differet type of material were carefully elected accordig to the geologic map. To reduce the ifluece of water cotet, the tet were all performed i dry eao durig November to Jauary. The portable direct hear teter The laboratory direct hear teter are commoly ued to obtai the hear tregth of geomaterial (Taylor, 98; Skempto ad Bihop, 9; Matuoka ad Liu, 998). The mechaim of thoe teter are imilar, i.e. the geomaterial i the hear box wa heared alog a hear plae by the hear force applied to the box. The hear box ca be a large a cm by cm to accommodate the ize effect if the ample poee larger ize particle. I geeral, a direct hear teter adopt a level loadig ytem to provide ormal tre. To avoid icliatio of the upper box due to differetial vertical deformatio i hearig, the ed of preure rod i deiged a a ball agait a cocaved roud hole i the top plate. The capacity of the teter i defied by the jack providig the hear force, which ca be cotrolled by a ervo-cotrolled ytem.. Compoet ad etup The portable direct hear teter (Fig. ) cotai the followig compoet: () Icliable platform: carrie the hear boxe. It ca be iclied by maually hydraulic jack to iduce lidig of the upper hear box. () Shear box: i cm log, cm wide ad cm high, i.e. cm high for both upper ad lower halve. The lower hear box i fixed to the icliable platform. The upper half ca be either freely to lide or fateed by crew to chage the clearace betwee upper ad lower boxe. () Slide rail: i attached o a icliable platform. It i coected with four roller of the upper hear box. () Hydraulic jack: hold lide bracket o the bae frame o that it lide to lift the icliable platform. It

3 8 K. J. Shou et al. / J Rock Mech Geotech Eg., (): 6 (a) The picture of the aembled portable direct hear teter. Shear box raied by jack Jack cm Lower hear box cm Normal force Upper hear box (b) The compoitio of the portable direct hear teter. Fig. Illutratio of portable direct hear teter. The hear boxe ca be raied ad tilted by the jack o the bae frame, ad the upper hear box ca lide dow ad hear the ample. ca alo adjut liftig rate ad icliig rate of the platform by regulatig the frequecy of jackig troke. () Slide bracket: i built o the bae frame. It upport the upper icliable platform by the upport force from hydraulic jack. (6) Bae frame: i the lower part of the teter. It poee four protrudig feet at four corer to prevet the teter from beig overtured by the iclied hear boxe. (7) Load iro plate: are ued to apply a ormal load o a tet ample. The iro plate will be placed upo the upper hear box ad lide together with the upper hear box. Thi teter ca take up to iro plate ( kg i ma) which are equivalet to approximately cm thick uperficial oil tratum. (8) Digital protractor: i ued to meaure the iclied agle of the hear box carryig platform at failure. The accuracy of the applied digital protractor i. for a iclied agle le tha, ad. for a iclied agle larger tha.. Tet procedure for the imple field direct hear teter () Collect the colluvium from the bottom of colluvial lope. I order to avoid the ifluece of heterogeeity i vertical directio, a cm by cm by cm pit i dug to obtai the colluvial material. () Mix the colluvial material thoroughly after beig creeed by a mm ieve, ad the depoit the colluvial material evely ito the hear box. () To coider the ifluece of compacte, the origial colluvial lope urface ad the re-compacted ample i the hear box are teted by a pocket peetrometer. To compact the ample comparable to the origial tate, the peetrometer readig of the re-compacted ample i matched with the readig of the origial colluvial lope urface. () Place oe iro plate above the re-compacted colluvium ample. To apply the vertical load i a more uiform way, level i ued to check the flate of the iro plate. () Looe the four crew at both ide of the upper hear box i cotact with lide rail, ad the adjut the clearace ( mm i adopted i thi tudy) betwee upper ad lower hear boxe by the bolt ad waher at both ide of the upper hear box. (6) Add more iro plate accordig to the deigated ormal load ad ue level to recheck the flate of upper face. The edge of the iro plate are lubricated i order to avoid the frictio that might iduce o-uiform vertical load durig the icliig of hear box carryig frame. (7) Ue the hydraulic jack to lift the iclied platform. The liftig rate i cotrolled by coutig the troke i a period accordig to agle chage rate (adapted to per miute i thi tudy). (8) Due to icliig of the platform, ample i the hear box will experiece icreaig hearig force util a hear plae i geerated by the lidig of the upper hear box. The digital protractor i ued to meaure the iclied agle of platform at lidig failure. It i recommeded to prepare ew colluvium ample for four differet ormal load, i.e. repeatig all the above eight tep. However, it could be acceptable to reue the ample, i.e. repeatig tep () (8), if the material i difficult to obtai. Beide, there i a limit of particle ize o accout of ize effect, oe teth of the ize of the hear box, i.e. mm i our cae, i uggeted a the limit for the deiged teter (Cerato ad Luteegger, 6).. Aalyi of the tet data The hear force of the developed teter i iduced by

4 K. J. Shou et al. / J Rock Mech Geotech Eg., (): 6 9 the icliig of the platform, ad the origi of the hear force i the iro plate placed above the ample. Whe the hear force i icreaed by further icliig the platform, the ormal load will be dimiihed imultaeouly. The relatiohip betwee iclied agle of the platform ad ormal tre o the hearig plae ca be expreed a F NWi co () A A where F i the ormal force, N i the total umber of iro plate applied, W i i the weight of oe iro plate, ad A i the ize of the hear plae ( cm for the developed portable direct hear teter). We alo have F NWi i () A A where F i the hear force. The ad obtaied by Eq. () ad () are ued to plot - curve to obtai the iteral frictio agle ad coheio c. Reult of calibratio To calibrate the portable direct hear teter, tet reult of thi teter were compared with laboratory reult of the mall- ad large-cale direct hear teter. Four colluvium-like ample, i.e. tadard ad, late debri, areaceou hale debri ad mixture of gravel ad ad, were teted.. Tet reult Stadard ad ample were teted by the portable direct hear teter ad the mall-cale direct hear tet with 6. mm cylidrical hear box. The iteral frictio agle of tadard ad meaured by the mall-cale direct hear teter i., but coheio wa extremely low. Alteratively, the iteral frictio agle meaured by the portable direct hear teter i 8.6, a how i Fig...d.. =8.6, c=. kpa d.. =., c=. kpa Fig. Compario of direct hear tet reult of ad (.d.. repreet imple field direct hear tet, d.. repreet covetioal laboratory direct hear tet). Sample coit of % gravel ad % ad, ad are ued a a artificial colluvium. Four differet ormal load, i.e..,.8,. ad. kn were applied by a certai umber of iro plate. However, the ormal tre for the portable direct hear teter mut be defied by the iclied agle of platform at failure. A how i Fig., the iteral frictio agle obtaied by the portable direct hear teter ad laboratory large-cale direct hear tet are. ad 6., repectively. I additio, late debri ample obtaied from Liha ladlide area (Shou ad Che, ) were alo teted by the portable direct hear teter ad the laboratory large-cale direct hear teter. The portable direct hear teter give a iteral frictio agle of 9. ad a value of coheio of.6 kpa. With a light dicrepacy, the laboratory large-cale direct hear teter give a iteral frictio agle of 7. ad a value of coheio of.9 kpa (ee Fig. ). 7 6 d.. =6., c=.78 kpa.d.. =., c=. kpa 6 7 Fig. Compario of direct hear tet reult of mixture of gravel ad ad (abbreviatio.d.. ad d.. defied i Fig. ). d.. =7., c=.9 kpa.d.. =9., c=.6 kpa Fig. Compario of direct hear tet reult of late debri (abbreviatio.d.. ad d.. defied i Fig. ). Two et of areaceou hale colluvium ample were collected from Wufeg, i.e. the et of Chola formatio ad the et of Siagha phae of Toukaha formatio. Similarly, thee two et of ample were teted by the two teter with four differet ormal load a well. For the former et of ample, the portable direct hear teter give a iteral frictio agle of 8.87 ad a value of coheio of. kpa. I additio, the laboratory large-cale direct hear teter give a iteral frictio agle of 8. ad a value of

5 K. J. Shou et al. / J Rock Mech Geotech Eg., (): 6 coheio of.7 kpa, a how i Fig.. For the later et of ample, a iteral frictio agle of 6.8 ad a value of coheio of.7 kpa were foud by the portable direct hear teter, ad a iteral frictio agle of. ad value of coheio of.8 kpa were obtaied by laboratory large-cale direct hear teter (ee Fig. 6). 6 d.. =8., c=.7 kpa.d.. =8.87, c=. kpa 6 7 Fig. Compario of direct hear tet reult of Chola formatio areaceou hale colluvium (abbreviatio.d.. ad d.. defied i Fig. ). d.. =., c=.8 kpa 6 7 Fig. 6 Compario of direct hear tet reult of Toukaha formatio areaceou hale colluvium (abbreviatio.d.. ad d.. defied i Fig. ).. Correlatio formula Correlatio formula were etablihed for iteral frictio agle meaured by the portable direct hear teter ad laboratory direct hear teter. Baed o the reult of five ample, liear regreio ca be applied to obtai the correlatio formula a how i Fig. 7. For implicity, the relatio wa ideally et to cro the origi of the coordiate. Thi liear regreio obtai the correlatio of iteral frictio agle a =.97 () Iteral frictio agle δ ( ) 7 6 δ=.797θ+., R =.9.d.. =6.8, c=.7 kpa δ=.97θ, R =.9 Iteral frictio agle θ ( ) Fig. 7 Liear correlatio for iteral frictio agle from the imple field direct hear tet ad laboratory direct hear tet. where θ deote the iteral frictio agle meaured by the portable direct hear teter ad deote the iteral frictio agle obtaied by the laboratory direct hear teter. The coefficiet of determiatio (R ) i.9 for thi fittig lie. Allowig the relatiohip lie to itercept a coordiate axi, the liear regreio give the relatio:.797. () The coefficiet of determiatio (R ) for thi fittig lie i.9. The reaoably good R value how that both formula expre good correlatio of θ ad.. Dicuio of reult The reult i Fig. 6 how that iteral frictio agle meaured by portable direct hear teter are % % larger tha thoe meaured by mall- or large-cale direct hear teter i the laboratory. It i alo worth otig that the iteral frictio agle ad reidual hear agle ted to be larger tha the theoretical miimum if the ample i heared uder lower ormal tre (Bradl, ). Becaue the ormal load were deducted by the icliig of platform, the ormal tree for the portable direct hear teter are maller tha thoe for the laboratory direct hear teter (ee Fig. 6). It might be the reao that the portable direct hear teter lightly overetimate the iteral frictio agle. The correlatio betwee the portable direct hear tet ad the laboratory direct hear tet wa baed o the tet of oly four differet type of colluvium-like geomaterial. Therefore, the correlatio might have a applicatio limitatio of the iteral frictio agle. To have more accurate correlatio, the calibratio for geomaterial with tregth i other rage i eceary. I additio, coheio meaured by portable direct hear teter are much maller tha thoe meaured by mall- or large-cale direct hear teter. A the adopted colluvium-like geomaterial poe relatively lower coheio, it i difficult to have accurate meauremet of coheio. Thu more tet data, epecially for thoe geomaterial with higher coheio, are eceary to further ivetigate thi dicrepacy. Applicatio The portable direct hear teter wa applied to the tudy of colluvium i Cetral Taiwa. The tet were performed i the eight ite elected i: () four ite i the lateritic formatio, () two ite i the Chola formatio, ad () two ite i the Siagha phae of Toukaha formatio. Table how particle ize ditributio of lateritic material i the tudy area, which cotai gravel

6 K. J. Shou et al. / J Rock Mech Geotech Eg., (): 6 (coare) ad lateritic oil (fie). The lateritic formatio i compoed of reddih brow clayey oil a cemetatio betwee gravel, ad their phyical propertie vary dramatically. It reveal from Table that the gravel cotet i 78% 86%. A the maximum particle ize (D max ) i aroud cm, to avoid removig too much large ize gravel, we cree the geomaterial by a 76 mm ieve itead of the mm oe. Table how particle ize ditributio of ample collected i two ite i Chola formatio ad two ite i Toukaha formatio. The C c, C u value i Table alo reveal that the particle ize of Toukaha formatio i more uiform tha the particle ize of Chola formatio. Table Characteritic of lateritic colluvium i the tudy area. Site Dry uit weight Size ditributio (g/cm ) Gravel (%) Sad (%) Silt (%) Houli Terrace/outh.8 8 Dadu Terrace/orth Dadu Terrace/orth. 8 6 Dadu Terrace/wet. 86 Table Characteritic of areaceou hale colluvium i the tudy area. Site d D D D 6 Sad Silt (g/cm C ) (mm) (mm) (mm) c C u (%) (%) Chola Formatio/ Wufog Chola Formatio/Taipig Toukaha Formatio/ Siagha Phae/ Wufog Toukaha Formatio/ Siagha Phae/ Taipig The reult of the imple field direct hear tet performed by the portable direct hear teter are ummarized ad dicued below: () The iteral frictio agle ad coheio of gravel colluvium meaured by the portable direct hear teter were 8 ad. kpa, repectively, ad the iteral frictio agle obtaied by the correlatio formula raged from. to.6 (ee Table ). Thee reult how more gravel i the ample will give larger iteral frictio agle. Alo the rage of the tet reult reaoably iclude the iteral frictio agle of 7 obtaied by a large-cale i-itu direct hear tet i thi area (Li, 6). () The iteral frictio agle ad the coheio of Chola formatio colluvium i Taipig ad Wufeg were ad.. kpa, repectively (a how i Table ). For the Siagha phae of Toukaha formatio, the reult i Table how the iteral frictio agle of ad coheio Table Reult of imple field direct hear tet i the tudy area by the portable direct hear teter. Area Site Coheio Iteral frictio agle( ) c (kpa).d.. * Eq. () ** Eq. () ** Houli Terrace/ outh Lateritic Dadu Terrace/orth gravel area Dadu Terrace/orth Dadu Terrace/wet Chola Formatio/Wufog Chola Areaceou hale area Formatio/Taipig Toukaha Formatio/Siagha Phae/ Wufog Toukaha Formatio/Siagha Phae/ Taipig Note: * mea imple field direct hear tet by the portable direct hear teter; ** mea to itroduce.d.. reult ito Eq. () or Eq. (). of..8 kpa, repectively. The reult how that iteral frictio agle are lower i the more uiform Toukaha formatio. () Accordig to a literature review of 6 large-cale direct hear tet (Li, 6), the iteral frictio agle of areaceou hale i Weter Taiwa i i a rage of 6 7, lower tha the rage obtaied by the portable direct hear teter i thi tudy. However, it how a cloer approximatio for the iteral frictio agle of. 6. regulated by the correlatio formula. 6 Cocluio ad uggetio I thi tudy, a portable direct hear teter wa deiged to tackle the icoveiece ad expeivee of the covetioal large-cale i-itu direct hear tet. It ca be eaily aembled ad applied for the imple field direct hear tet. For the colluvium i Cetral Taiwa, baed o the compario betwee tet reult i thi paper ad thoe from laboratory direct hear tet, the liear correlatio formula, i.e. Eq. () ad (), were etablihed. The tet reult i the field idicate that the portable direct hear teter ca reaoably etimate the iteral frictio agle of remolded colluvium. The tudy alo illutrate the beefit of the portable direct hear teter, icludig eay to ue, very efficiet, ad le expeive. Although the ormal tre might be diturbed durig the icliig ad lidig of the hear box, thi teter i reaoably good to gai the peak hear reitace (Lope et al., ; Narejo, ), i which we carefully prepare the ample ad properly perform the tet. Sice there i o loadig frame to provide reactio force, the ormal load ca be oly applied by

7 K. J. Shou et al. / J Rock Mech Geotech Eg., (): 6 deadweight. Ad the ormal load reduce whe the upper hear box iclie. The limitatio of ormal load make more iaccuracy from other ource, uch a the frictio betwee teter compoet ad the ueve hear plae. More ivetigatio o the derivatio of the formula, epecially the part of ormal tre, i trogly uggeted. More tet are eceary to improve the accuracy of the correlatio formula ad further ivetigate the dicrepacy of coheio. However, it i worthy to further improve the portable direct hear teter to overcome it hortcomig i loadig ad cotrollig mechaim. More properly applyig the ormal load, icreaig the capacity of ormal load, ad more preciely cotrollig the rate of liftig are uggeted for the further developmet of thi teter. Ackowledgemet The work preeted i thi paper wa made poible through the upport of the Natioal Sciece Coucil (NSC9--E--), Taiwa, Chia. The author are idebted to the uggetio of the aoymou reviewer ad the upport of Prof. J. R. Lai ad P. S. Li. Referece ASTM. D8- Stadard tet method for direct hear tet of oil uder coolidated draied coditio. Wet Cohohocke, PA: ASTM Iteratioal,. Bradl H. Groud upport-reiforcemet, compoite tructure. I: GeoEg. Melboure, Autralia: Techomic, : Briaco L, Girard H, Poulai D. Slope tability of liig ytem experimetal modelig of frictio at geoythetic iterface. Geotextile ad Geomembrae,, (): 7 7. Cetral Geology Survey. The geological map of Taiwa :. Taiwa: MOEA,. Cerato A B, Luteegger A J. Specime ize ad cale effect of direct hear box tet of ad. Geotechical Tetig Joural, 6, 9 (6): 7 6. Che T C. Ladlide iduced by heavy raifall for year after Chi-Chi Earthquake, Taiwa. Geophyical Reearch Abtract, EGU,, 7: 867. Fell R, Hugr O, Leroueil S, Riemer W. Geotechical egieerig of the tability of atural lope, ad cut ad fill i oil. I: GeoEg. Melboure, Autralia: Techomic, :. Hamel J V, Flit N K. Failure of colluvial lope. Joural of the Soil Mechaic ad Foudatio Diviio, ASCE, 97, 98 (): Kakuo B G, Shimizu H, Nihimura S. Reidual tregth of colluvium ad tability aalyi of farmlad lope. AGI: CIGR E-Joural, (Vol. ). Karikari-Yeboah O, Gyai-Agyei Y. Stability of lope characteried by colluvium: ivetigatio, aalyi ad tability. I: GeoEg. Melboure, Autralia: Techomic, :. Li C W, Shieh C L, Yua B D, Shieh Y C, Liu S H, Lee S Y. Impact of Chi-Chi Earthquake o the occurrece of ladlide ad debri flow: example from the Cheyula river waterhaded, Natou, Taiwa. Egieerig Geology,, 7 (/): 9 6. Li Y W. Deig of imple i-itu direct hear teter with applicatio to colluvium i Cetral Taiwa. M.S. Thei. Taichug, Taiwa: Natioal Chug-Hig Uiverity, 6 (i Chiee). Liu S H, Su D, Matuoka H. O the iterface frictio i direct hear tet. Computer ad Geotechic,, (): 7. Lope P C, Lope M L, Lope M P. Shear behaviour of geoythetic i the iclied plae tet ifluece of oil particle ize ad geoyyhetic tructure. Geoythetic Iteratioal,, 8 (): 7. Maral R J. Mechaical propertie of rockfill ad gravel material. I: Proceedig of the 7th Iteratioal Coferece o Soil Mechaic ad Foudatio Egieer. Mexico: Sociedad Mexicaa De Mecaica, 969: Matuoka H, Liu S. Simplified direct box hear tet o graular material ad it applicatio to rockfill material. Soil ad Foudatio, 998, 8 (): 7 8. Matuoka H, Liu S, Su D, Nihikata U. Developmet of a ew i-itu direct hear tet. Geotechical Tetig Joural,, (): Narejo D B. A imple tilt table device to meaure idex frictio agle of geoythetic. Geotextile ad Geomembrae,, (): 9 7. Shou K J, Che Y L. Spatial rik aalyi of Liha ladlide i Taiwa. Egieerig Geology,, 8 (/): 99. Skempto A W, Bihop A W. The meauremet of the hear tregth of oil. Geotechique, 9, (): 9 8. Skempto A W. Reidual tregth of clay i ladlide, folded trata ad the laboratory tet. Geotechique, 98, (): 8. Stark T D, Choi H, McCoe S. Draied hear tregth parameter for aalyi of ladlide. Joural of Geotechical ad Geoevirometal Egieerig, ASCE,, (): Taylor D W. Fudametal of oil mechaic. New York: Joh Wiley ad So, Ic., 98. Yu X, Ji S, Jaoya K D. Direct hear tetig of rockfill material. I: Proceedig of Seio of GeoShaghai 6. Shaghai, Chia: ASCE, 6: 9. Keh-Jia Shou (Profeor, Ph.D., Departmet Head) i ow workig with Departmet of Civil Egieerig, Natioal Chug-Hig Uiverity, Taiwa, Chia (ice 99). He got hi Ph.D. degree (Civil Egieerig) from Uiverity of Mieota, U.S.A. (99). Hi experiece iclude: () Seior Pricipal Egieer, Shao & Wilo, Seattle, USA (8/ 8/9); () Viitig Profeor, TTC, Louiiaa Techical Uiverity, USA (6/ 6/); () Viitig Profeor, RCUSS, Kobe Uiverity, Japa (/ /); () Reearch Egieer, CSIR/Miigtek, South Africa (998/ 999/); () Geotechical Egieer, Natioal Expreway Egieerig Bureau, Taiwa (99 99). Hi major iteret iclude rock mechaic, rock egieerig, egieerig geology, trechle techologie, ad geotechical egieerig. Cotact iformatio: Departmet of Civil ad Evirometal Egieerig Natioal Chug-Hig Uiverity No., Kuo Kuag Road, Taichug, Taiwa 7, Chia Tel: (886) -87-# Fax: (999) kjhou@drago.chu.edu.tw