地震作用下土工格栅加筋土挡土墙动力响应分析

Dynamic Response Analysis of Geogrid-Reinforced Soil Retaining Walls Subjected to Seismic Load

采用连续介质快速拉格朗日差分方法对一座土工格栅加筋土挡土墙地震作用下的动力响应进行了计算分析,将加筋材料中最大拉力、动土压力、加速度放大效应的数值模拟结果与FHWA和公路加筋土工程设计规范计算值进行了对比分析。计算分析表明,挡土墙面板位移与加筋材料拉力均随时间累计增加,地震持续时间对加筋土挡土墙动力影响明显;在地震末期,加筋材料拉力、动土压力数值计算值要明显大于规范计算值;地震时加速度沿墙高有明显的放大效应,加筋土挡土墙墙趾分担了相当一部分动土压力。当前规范设计方法对这些因素均未给予充分的考虑。

The dynamic responses of a pratical geogrid-reinforced soil retaining wall is illustrated with the Fast Lagrangian Aanlysis for Continuum method（FLAC）.The numerical results including the maximal tensile force of the geosynthetical reinforcement,dynamic lateral earth pressure,acceleration amplification are compared with the results obtained from FHWA and Specifications for Design of Highway Reinforced Earth Engineering.The results show that： the facing displacements and tensile forces in the geosynthetical reinforcement are accumulated with the duration of the vibration.The numerical results of tensile force and dynamic lateral earth pressure at the end of vibration are much greater than the results calculated by using the analysis approach of designing code.Meanwhile,the acceleration amplification and toe load are not considered properly by current designing code as well.