Abstract

The earthquake is the natural disaster which can produce great harm, and it happens around the world every year. During the earthquake, the building foundations become invalid induced by the liquefaction which is beyond 50%. Therefore, domestic and foreign academia and engineers have placed great emphasis on the influences of the stone columns in saturated sand foundation. Recently, the researchers have certain knowledge of the reinforcement mechanism, reinforcement effects and the design method for resisting the liquefaction. However, the studies about the reinforcement of saturated silt foundation are rare, even still a blank.

Combining with the National Youth Science fund projects named”the liquefaction mechanisms of the saturated silt and the foundations reinforced by the stone columns dynamic characteristics”. In this paper, a series of laboratory experiments are conducted including resonant column tests, cyclic triaxial tests and shaking table tests. Mainly contents as following:

1. It explores the influences on the dynamic shear modulus, damping ratio and the stress strain by resonant column test, such as the dry density, confining pressure.

2. It makes analysis of the matters influencing on the liquefaction of silt, such as dry density, confining pressure and the content of silt by the cyclic triaxial test. It can be observed that clay content have different effects on its dynamic strength. In this paper, we make attempts to put forward a proposal about the growth model for the pore pressure of silt.

3. A series of shaking table tests are conducted including the sand foundation in field foundation, the silt foundation in field foundation and stone column composite foundation. It compares the pore pressure ratio in any case. It is found that the liquefaction resistance of silt foundation is better than the sand which caused by the stone columns who can make effects on drainage decompression and damping.

Key Words: liquefaction of silt; clay content; dry density; liquefaction resistance; stone column composite foundation; small shaking table test