剪切历史对砂土液化特性影响的模型试验系统

Model Test System for Studying the Effects of Shear History on Sand Liquefaction Characteristics

摘要:

介绍了一种研究剪切历史对砂土液化特性影响的模型试验系统.通过倾斜模型箱，利用重力在倾斜方向上的分量给模型试样施加不同大小的预剪切应变.将模型箱恢复至水平状态，利用小型振动台加振使砂土达到液化状态，同时通过量测系统采集模型试样内部的超孔隙水压和加速度数据，对砂土的液化特性进行分析.试验结果表明，具有剪切历史的砂土在振动过程中超孔隙水压上升幅值更小，说明剪切历史可以增强模型地基的液化抵抗能力.

Abstract:

A model test system was introduced for studying the effects of shear history on sand liquefaction characteristics. First, different levels of pre shear strains were applied on the model foundation by using the component force of gravity along the tilt direction through tilting the shear box. Then, the sand was liquefied by using a small shaking table, and simultaneously excess pore water pressure and acceleration within the foundation were collected by measurement system to analyze the sand liquefaction characteristics. Test results show that the buildup of excess pore water pressure within the soil with shear history is smaller than that without shear history. In other words, shear history can enhance the liquefaction resistance of sand.