地震类型对加筋土挡土墙长期蠕变后动力响应的影响

Effect of earthquake type on dynamic response of geosynthetic-reinforced soil walls after long-term creep

针对人们对加筋土挡土墙长期蠕变后地震动力响应特性认识还很模糊的问题,利用ABAQUS软件,以一高8m高黏性土填土的加筋土挡土墙为例,同时考虑土体与筋材蠕变效应,对其经历5a蠕变后再遭遇地震作用的整个过程进行了有限元模拟分析,并重点研究了不同类型地震波的影响.其中,土体采用实用弹塑-黏塑性模型,筋材采用土工合成材料循环受载、蠕变和应力松弛统一本构模型.计算结果表明:土体与筋材的明显蠕变效应会导致墙体运行多年后再在地震作用下的总水平位移有较大增加;强震作用下墙体会同时存在内外部2个较危险的滑裂面;峰值相同的不同类型地震波所引起的墙体动力反应差别可能会比较明显,目前只应用加速度峰值进行加筋土挡土墙抗震设计的做法还欠合理.

In order to study the seismic behavior of geosynthetic-reinforced soil walls after long-term creep,the process of an 8 m-high cohesive back-filled geosynthetic-reinforced soil retaining wall subjected to earthquakes after five years of creep was analyzed with consideration of creep effects of the soil and the reinforcement material simultaneously using the finite element software ABAQUS.The effects of different types of earthquake waves were emphatically studied.In the analysis,the soil and the reinforcement material were modeled using an elastoplastic-viscoplastic model and a unified constitutive model,respectively.The results show that the remarkable creep effects of the soil and reinforcement material can increase total lateral displacement of the wall under earthquake loads after long-term creep;inner and outer potential failure surfaces exist simultaneously under strong earthquake loads;and the differences of dynamic response of the wall may be large under different earthquake waves with same peak acceleration values,thus the current seismic design methods only using peak acceleration values of earthquakes may be lack of rationality.