photo: deltaport berth 2 project

Transcription

1 photo: deltaport berth 2 project GROUND I MPROVEMENT

2 BOLEO MARINE TERMINAL Vancouver Pile Driving Ltd. (Vanpile) was involved in the development of the The final Stone Column spacing that was accepted was a 2.25m triangular pattern. The Geotechnical Engineer, upon reviewing the CPT results, proposed a quality control method based on amperage that allowed Vanpile to construct the columns in such a fashion to satisfy the requirement. Vibro nose cone and gravel delivery tube for bottom feed unit. The two enclosed Betterground Monitoring System (BMS) sheets detail all aspects of the column installation. Sheet No. 1 provides the column details at the top of the page. Constructing the column to the required depths is shown in red with the accompanying amperage shown in green. Sheet No. 2 details the volume of stone placed in relation to amps at each penetration of the vibro. marine facilities at the Boleo Marine Terminal, located at Santa Rosalia, Baja California Sur. The facilities consisted of a 350m wharf and four mooring dolphins. The wharf and dolphins were supported on driven open-ended pipe piles founded a specified length into sedimentary bedrock. The granular soil above the bedrock was susceptible to liquefaction and ground treatment was specified. As this portion of the project was design build, Vanpile proposed using Stone Columns installed utilizing the Dry Bottom Feed method. In order to satisfy the specifications, three test patterns were proposed, after which CPT testing was carried out to verify the densification results. Skip bucket adding stone to the hopper. 2

3 Spud barge at Santa Rosalia, Baja California, penetrating 11m of water + 12m of granular soil. By monitoring each Stone Column installed, the BMS data allows the Geotechnical Engineer to assess the quality of the installation. Should any change be required in the installation method based on the BMS data, the change can be initiated immediately. monitoring system all Stone Columns were installed and could be approved by the Geotechnical Engineer on a daily basis. This is a marked improvement in the quality control of the installation of Stone Columns. The installation of the Stone Columns was by means of working off a spud barge accompanied by a material barge. The spud barge supported all the equipment while the material barge, utilizing a long stick excavator, supplied the stone to the skip bucket. All column layout was by means of GPS. In the cab of the crane was located the computer monitoring system. This system allows the crane operator to construct the column in the specified method. By means of the BMS data and the computer Completing the stone column. 3

4 SHEET NO. 1 4

5 CRITERIA AT BOLEO 150 AMP SHEET NO. 2 5

6 STONE COLUMN INSTALLATION MONITORING Betterground quality monitoring and control system The quality control recorder is a touchscreen located in the rig operator cabin. (see on right) Control of valves and similar auxiliary components The unit can act as a remote control for regulating the pressure of flow of water, air, or even cement grout. This regulation can be programmed to follow an automatic or semi - automatic rule where these flows are regulated depending on the depth level. Operator guidance system The software (shown on right) guides the operator to install a specified column diameter or achieve required ampere layer by layer as required. This is accomplished by the green bar graph on the right of the display (titled "Compaction"). The green vertical bar moves upward and downward as the crane operator raises and lowers the vibro. The diagram on the bottom right indicates in orange the height of stone column installed, the depth as shown by the green bar, and the remaining height of column to be installed in white. The valve controllers for the various air lock chambers of the Double Lock rig are shown in the left part of the display, indicating status of the valve, flow rate and pressure. At the bottom of the screen, a row of buttons (green, last one yellow) shows the present position of the control computer in the process of installing an offshore stone column. The operator works sequentially from the leftmost to the rightmost button during the installation process, with the presently available selection in yellow and the already completed steps green. This way we are able to teach most operators to run the system error free without ever reading a manual. 6

7 Column for Construction Depth Bar Height of Column Constructed Green Vertical Bar 7

8 Lifting Head PRESSURE CHAMBER INJECTION SYSTEM (PCIS) Gravel Hose Hopper Although Vanpile purchased their dry bottom feed vibros from Betterground, there is available dry bottom feed for underwater stone columns utilizing the PCIS equipment as shown at right. As can be seen from the cross section on the adjacent page, the PCIS is operating well below sea level. The PCIS as shown in the sketch is the newest evolution of marine bottom feed stone column installation equipment. Airtight Gate Receiver Tank Silo Tube In the example shown here, the gravel is transported via a 6 inch flexible gravel hose. In the variant of this system, the gravel can alternatively be placed by a bucket in the hopper. Key to the high quality installation capability of the PCIS is the airtight gate on top of the receiver tank that locks the gravel from atmospheric pressure and puts it under an over-pressure that ranges between 2 to 6 bars and is dependent on the operating depth of the rig. Vibro Under the applied excess air pressure in the interconnected chamber consisting of a receiver tank, silo tube and tremie pipe, gravel is injected into the soil at the bottom of the tremie pipe near the tip of the vibroprobe nose, hence the name "pressure chamber injection system." Compared with the Single Large Tank system, the advantage of the PCIS is that below the gate there is exactly ONE full batch of gravel filled in with each opening of the airtight gate. This not only allows for fewer numbers of open-close cycles of this gate, but also an exact recording of gravel batches placed in the ground at defined depths. In a so called "Double Lock" variant of the same system, two airtight gates enclose the receiver tank on its top and bottom. PORT OF PATRAS LIQUEFACTION MITIGATION - BETTERGROUND OFFSHORE GROUND IMPROVEMENT Liquefaction mitigation In the 1990s, soil liquefaction caused by an earthquake destroyed parts of the Port of Patras. It needed, therefore, no convincing to install stone columns for liquefaction mitigation on this project. 8

9 Barge setup The barge of approx. 55m x 35m carried the 150 ton main crane that hoisted the vibroprobe. The photo below shows that the gravel supply was organized via silos and two conveyor belts that filled the gravel pump's hopper. The silos were refilled using a small auxiliary crane that unloaded the gravel barges into the silos on the main barge. Quantities (above) Breakwater: 4,830 stone columns, 16 m average length, 77,280 lm, 60,665 m 3 (1m diameter), square spacing 2.7 m. Quaywall: 3,073 stone columns, 10 m average length, 30,730 lm, 24,123 m 3 (1m diameter), square spacing 3.3 m. PCIS Pressure chamber injection system (PCIS) The underwater receiver tank with "schnorchel hose" for the pressure discharge of excess stone-transport-air to the surface was invented in 2000 by Alexander and Willhelm Degen and patented in some countries. For sites in deep waters in relation to the soil treatment depth, this system allows the classic double lock gravel pump to pneumatically transport the stones into an underwater receiver without counteracting water pressure while a receiver above water traditionally simply releases the excess air via a short tube or a venting cover on top of the receiver. Current new developments like water transport of the stones can avoid the relatively expensive pneumatic stone transport. The patented air discharge hose is now obsolete. 9

10 SOME NOTABLE VANPILE DENSIFICATION PROJECTS DELTAPORT BERTH 2 (2009) Four derricks working double shift i nstalled in excess of 10,000 stone columns to depths of 28m below water lev el. 10

11 NANAIMO C RUISESHIP TERMINAL (2011) 2 cranes operating 2 shifts per day installed in excess of 700 stone columns to depths of 15m to a max of 26m. VANC OUVER CONVENTIO N C E NT ER (2006) Expansion project including installation of approximately Ø steel pipes as well as both marine and land based densification utilizing the dry bottom feed method for constructing the stone columns. 11

12 RECENTLY COMPLETED CONTRACTS INVOLVING GROUND DENSIFICATION Pacific Coast Terminals - New Shiploading System, Port Moody, BC Vancouver Convention Center Expansion, Vancouver, BC 2nd Narrows Bridge Seismic Retrofit, North Vancouver, BC Boleo Marine Terminal, Santa Rosalia, Baja California Oak Street Bridge Seismic upgrade, Vancouver, BC Fraser River Tower Seismic Upgrade, Richmond, BC Nanaimo Cruise Ship Terminal, Nanaimo, BC Bayshore Shoreline Phase II, Vancouver, BC Deltaport Berth 2, Delta, BC Vancouver Pile Driving Ltd. 20 Brooksbank Avenue North Vancouver, B.C., Canada V7J 2B8 Tel: Fax: Web: (604) (604) vanpile@vanpile.com