地震作用下饱和回填砂土重力式挡土结构滑动与转动位移分析

 预测地震作用下重力式挡土结构的位移是基于位移抗震设计方法的关键。基于Newmark滑动理论、超孔隙水压力应力模型和累积损伤原理，建立饱和回填砂土中超孔压比时程计算模型，以及墙体滑动和转动临界加速度时程计算模型。基于所建立的模型，提出用于计算饱和回填砂土重力式挡土结构滑动和转动位移的计算方法。采用该方法，分析土体参数和地震动参数对墙体滑动及转动位移的影响，并对墙体滑动与转动的耦合作用进行研究。结果表明，填土不发生液化的情况下，滑动位移对土体相对密度和墙体与地基土间的摩擦角十分敏感；转动位移对输入地震的震级、水平加速度和竖向加速度、填土的内摩擦角、墙背摩擦角和相对密度均较为敏感。超孔隙水压力对墙体滑动和转动位移的影响不可忽视。在地震作用下墙体与墙后填土破坏土楔体共同运动的假设条件下，墙体滑动与墙体转动相互抑制。

Seismic sliding and rotational displacement of gravitational retaining structures with saturated backfill sand

The prediction of displacement is essential in the displacement-based seismic design of gravitational retaining structures with saturated backfill sand. Based on the sliding theory of Newmark，the stress-based excess pore pressure model and the cumulative damage theory，the models for predicting the time histories of excess pore pressure ratio，rotational and sliding critical accelerations were proposed. The methods of calculating the rotational and sliding displacements were established using the proposed models. The effects of soil parameters and ground motion parameters on sliding and rotational displacements of the wall were studied with the proposed methods and the coupling effect between sliding and rotational displacements was also analyzed. The results revealed that under the non-liquefaction condition of backfill sand，the sliding displacement of gravitational retaining structures with saturated backfill sand was very sensitive to the relative density and friction angle of soil at the base of the wall. The rotational displacement was sensitive to the magnitude of earthquake，horizontal and vertical seismic accelerations of ground motion，friction angle and relative density of soil and angle of friction of soil against wall back. The influence of excess pore pressure on sliding and rotational displacements cannot be ignored. The results about the coupling effect between rotational and sliding displacements indicated that when the sliding and rotation of wall occurred simultaneously，rotation and sliding inhibited each other.