Design consideration of pile foundations of high speed rail project in seismic area

The area of this study is in the southern part of THSR alignment from TK188 to TK343 with a length of 155 km approximately. The geological condition in this region consists of compressible alluvial deposits in the upper soil strata. This paper focuses on some of the special technical features to be considered in the design of pile foundations, including effects of particular site conditions, pile group effects, lateral resistance of pile cap and flow slide of liquefiable soil etc. For foundation design, significant efforts have been placed on soil-pile interaction (p-y, t-z and q-w relationships) through verification and calibration of models from pile load tests. The pullout resistance of piles is studied to a great extent based on full-scale pullout testing. Sensitivity of soil spring to the design of piles foundation and piers is also analyzed.