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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。
Predicting the displacement of gravity retaining structure under the action of earthquake is the key of displacement-based seismic design method. Based on the Newmark sliding theory, the theory of excess pore water pressure stress and the principle of cumulative damage, the time-dependent calculation model of excess pore water pressure ratio in saturated backfill sand and the calculation model of the critical acceleration time series of sliding and rotating wall are established. Based on the established model, a calculation method for calculating the sliding and rotational displacement of saturated backfill sand gravity retaining structure is proposed. This method is used to analyze the influence of soil parameters and ground motion parameters on the sliding and rotational displacement of the wall, and the coupling effect between the sliding and rotation of the wall is studied. The results show that the sliding displacement is very sensitive to the relative density of the soil and the friction angle between the wall and the foundation soil when the filling does not occur liquefaction. The rotational displacement has great influence on the magnitude, horizontal acceleration and vertical acceleration of the input earth, Internal friction angle, friction angle and relative density of the back wall are more sensitive. The effect of excess pore water pressure on the sliding and rotational displacement of the wall can not be ignored. Under the assumption that the wall is wedged with the wall wedges after the earthquake, the wall sliding and the wall rotation are mutually restrained.