倾斜可液化场地中矩形闭合型地下连续墙桥梁基础动力特性研究

矩形闭合型地下连续墙作为一种新型桥梁基础,在倾斜可液化场地中的动力响应特性还不清楚。基于离心机振动台试验结果,研究在倾斜可液化场地中的不同地震动工况下,矩形闭合型地下连续墙桥梁基础抵抗土体液化的性能及其位移(沉降、转角和水平位移)特征。通过对比在三种地震动(小震峰值为0.05g、中震峰值为0.13g、大震峰值为0.50g)作用下,远场土体与墙内土芯的动力响应特征,证实了矩形闭合型地下连续墙基础的抗液化性能。综合分析在3种地震动工况下,矩形闭合型地下连续墙基础的位移特征,讨论了其在倾斜可液化场地中作为桥梁基础的优劣性;分析发现在中震工况下,在可液化场地中矩形闭合型地下连续墙基础作为桥梁基础的性能最为显著。此外,通过对比有、无承台的两组矩形闭合型地下连续墙基础的位移特征,分析了矩形闭合型地下连续墙基础顶部承台的作用。

Seismic behavior of rectangular closed diaphragm walls as bridge foundations in slope liquefiable deposits

As a new type of bridge foundations, the seismic behavior of the rectangular closed diaphragm wall (RCDW) in slope liquefiable deposits requires a deep investigation. The liquefaction mitigation capability and displacement characteristics (settlements, rotations, and horizontal displacements) of RCDWs as bridge foundations in slope liquefiable deposits in different shaking events are studied on the basis of dynamic centrifuge test results. A comparison of different responses of the soil in the far field and the soil core enclosed by RCDWs in three shaking events (peak values of small, moderate, and large shaking events are 0.05g, 0.13g, and 0.50g, respectively) verifies that RCDWs can mitigate liquefaction to some extent. On the basis of the displacement characteristics of RCDWs in these three shaking events, the merits of RCDWs serving as bridge foundations are discussed, and the discussion shows that RCDWs are the most advantageous for serving as bridge foundations in moderate shaking events in liquefiable deposits. Furthermore, the effects of caps on the displacement characteristics of RCDWs are analyzed based on the results of two different dynamic centrifuge tests.