Study of dynamic pore water pressure and axial strain in saturated sand-gravel composites;

A new type of test method called multi-spots axial strain sensor was elaborated,the development conception and test principle were also introduced.

Then,the sand liquefaction process is divided into four phases according to the different behavior of hysteresis loop,during which the development characteristics of axial strain are analyzed.

Based on the assumption of the plane-stress and three-dimensional stress state,the approximate calculation formulae of the mutual relation between the wall-thinning-ratio and the change-ratio of short axis of the cross-section were deduced respectively.