Practice of Large Penetration Test after 1999 Ji-Ji Earthquake Jiin-Song Tsai and Yean-Jhe Liou Department of Civil Engineering National Cheng Kung University

Soil-Structure Interaction Research Laboratory Aspects Field Conditions Facilities & Instrumentation Experiment & Results Summaries & Lessons

Soil-Structure Interaction Research Laboratory Liquefaction of Gravelly Ground BPT (Harder and Seed, 1986) –Effects of hammers and casings –BPT-SPT correlation FBPT (Sy and Lum, 1997) –Effects of casing friction (Mud-injection Becker) LPT (Daniel, Howie and Sy, 2003) –Scale effect of LPT’s (scale-up SPT) TLPT (Tsai, Huang and Liou, 2003) –Measurement of Energy Transfer

Soil-Structure Interaction Research Laboratory TLPT Project TLPT Research Team Dr. A.B. Huang (Planning and Coordination) Dr. J.S. Tsai and Diagnostic Eng. Consultant LTD. (Energy Measurement) Dr. P.S. Lin (Soil Investigation and Job Site Preparation) Dr. A.B. Huang Joint Project Coordinator Dr. D.H. Lee NSC Coordinator

Test Site & Ground Condition

Soil-Structure Interaction Research Laboratory Location

Soil-Structure Interaction Research Laboratory Liquefaction of Test Site Fu Tin Bridge Liquefaction Outlet South Levee of Da Li River

Soil-Structure Interaction Research Laboratory Layout Da Li River

Soil-Structure Interaction Research Laboratory Test Pit

Soil-Structure Interaction Research Laboratory Profile ( B-14 )

Facilities & Instrumentation

Soil-Structure Interaction Research Laboratory Casings of TLPT 170mm Mud inject 140mm 170mm 305mm 170mm 220mm 405mm BPT & FBPT TLPT (Close end) Conventional (Open end) Mud-Injection (Close end) 168mm232mm 208mm272mm Comparisons with BPT and FBPT

Soil-Structure Interaction Research Laboratory Steel Shoes P1, P2P3, P4, P5

Soil-Structure Interaction Research Laboratory BPT and TLPT Hammers

Soil-Structure Interaction Research Laboratory Three-Segment Casings P1, P2 P3, P4, P5

Soil-Structure Interaction Research Laboratory Instrumentation - Setup Strain transducer Accelerometer TNO signal conditioner Notebook computer Loadcell InstruNet M100 signal conditioner Notebook computer Set-A Set-B

Soil-Structure Interaction Research Laboratory Instrumentation – Set-A accelerometer ψ232mm casing strain transducer bolt accelerometer

Loadcell & Set-B Development

Soil-Structure Interaction Research Laboratory Loadcells P1, P2 P3, P4, P5

Soil-Structure Interaction Research Laboratory Q 1: How to place the sensors properly inside the tube under limit working space ? A 1: Prefabricate the sensors module on a plastic sheet for one-time easy pasting

Soil-Structure Interaction Research Laboratory Q 2: How to effectively cover sensors under limit working space to resist high water pressure ? A 2: Fill up the tube with silica gel

Soil-Structure Interaction Research Laboratory Q 3: How to isolate the sensors and wire cords from high temperature induced by welding ? A 3: Wrap them carefully using asbestos belts

Soil-Structure Interaction Research Laboratory Loadcell Calibration 500t MTS

Soil-Structure Interaction Research Laboratory Shop Prefabrication

Experiment Procedure

Soil-Structure Interaction Research Laboratory Installation Steps Double-check Set-B, and label 30cm marks on the tube. Erect the lower segment and slightly pound to the ground.

Soil-Structure Interaction Research Laboratory Pounding Steps Bolt Set-A sensors onto casing. Connect Set-A and Set-B to signal conditioners. Record blow counts of 30cm penetration. Stop pounding before Set-A sensors were dragged into the ground. Dismount Set-A.

Soil-Structure Interaction Research Laboratory Steps for next cycle Stretch Set-B cords to new outlet hole. Welding. Repeat the pounding steps until the upper segment done.

Soil-Structure Interaction Research Laboratory Correlate BPT -N b and SPT -N 60 Sy and Lum method (1997) No shaft friction R s

Soil-Structure Interaction Research Laboratory Results

Discussions

Soil-Structure Interaction Research Laboratory Unsolved puzzle 1: Unsolved puzzle 1: Why size effects on ENTHRU results are not clearly shown ?

Soil-Structure Interaction Research Laboratory Unsolved puzzle 2: Unsolved puzzle 2: Why N L30 numbers of same size casing are scattering?

Soil-Structure Interaction Research Laboratory Failure No meaningful data of Set B !! Why?

Soil-Structure Interaction Research Laboratory SimWave simulation Study Force-time history of Set-B ε=2.23×10 -3 ε allow =5×10 -2 Particle velocity doubled 1500 mm 5000 mm 400 mm Hammer radius=260mm weight=2.5t ψ232mm Segment 1 area=24127mm Set-B

Soil-Structure Interaction Research Laboratory Interpretation: High particle velocity fail the bounding between casing tube and strain gauges. Measures: Adopt longer strain gauges (lower accuracy) to provide larger glue area.

Soil-Structure Interaction Research Laboratory Summaries The first trial of local LPT (TLPT) is described and data are presented. Results of TLPT give an explanation to liquefaction of gravelly ground in the Ji-Ji Earthquake. Lessons learned give clues for future improvements.

Appreciate all involved… To be Continued …..