Pore Pressure Response During 1986 Lotung Earthquakes

In 1986, two significant earthquake events in Lotung, Taiwan were recorded with both acceleration and pore water pressure traces at different depths below the ground surface. One event (M=6.2) was recorded on July 30th with an epcientral distance of 6km, and the other (M=7.0) was recorded on November 14th with an epicentral distance of about 80 km from the site. To analyze the recorded data, a finite element procedure was developed. The procedure incorporates a newly developed bounding surface hypoplasticity model for granular soils and can handle multidirectional input motions. The finite element procedure takes into consideration pore water pressure buildup and dissipation, pore water movement relative to the soil skeleton, compressibility of pore water, initial values of k0, overconsolidation ratios, and rotational shear effects. This paper describes the field project and presents the analytical results based on the above procedure which include the multidirectional shaking effects. The analytical results compare well with the field measurements