Pore Pressure Increase and Evaluation in Saturated Sand Based on In Situ Liquefaction Tests

Abstract

Abstract Through self-developed testing technology, in situ liquefaction tests were conducted to investigate pore pressure responses of saturated sand in the field, and a new incremental model is proposed to predict pore pressure increase in saturated sand liquefaction. The pore pressure generation of saturated sand in the field is slower than that shown through the dynamic triaxial test. In situ testing results herein indicate that the effect of number-of-cycle is different from the results obtained from the dynamic triaxial test. The variation of pore pressure rise in the in situ tests initially increases then decreases with the increasing number of loading cycles rather than a monotonic decrease mode. Different from existing models, the new pore pressure model is directly expressed with in situ parameters, such as acceleration, buried depth, etc., which are commonly applied to describe soil characteristics in the field. The advantages of the proposed formula by in situ tests are that it avoids uncertain stress evaluation during establishment and application of the new model and can greatly reduce artificial errors. Comparisons between predicted and measured results indicate the reliability of the new model. The proposed model can conveniently evaluate the pore pressure increase of saturated sand in a free horizontal field.