高陡坡土工格栅加筋土堤地震动力响应分析

Analysis on Seismic Dynamic Response of Geogrid Reinforced Earth Embankment on High Steep Slope

为了研究不同地震波作用下高陡坡土工格栅加筋土堤任意时刻任意高度结构的位移和土工格栅受力大小,以某高陡坡土工格栅加筋土堤项目为研究对象,考虑结构位移和筋材受力的主要影响因素,提出厚高比的定义。采用了数值模拟和理论分析的方法,分析了同一高度下不同填土层厚的高陡坡土工格栅加筋土堤,在地震波作用下的位移、加速度、放大倍数情况,以及结构任意高度位移筋材受力大小的计算方法。结果表明:高陡坡土工格栅加筋土堤厚高比越小,结构耗散的地震动力能量越多,抗震性越好,相反则抗震性越差;厚高比越大,地震加速度下位移和土工格栅受力越大,相反则位移和土工格栅受力越小;随着地震加速度和厚高比的增大,土工格栅单元的最大轴力呈二次型增长模式,从上到下每一层填土中心附近土工格栅轴力线性减少;不同地震加速度下不同厚高比土堤的水平位移呈非线性增长模式,并且从上到下每一层填土中心处的位移呈二次型增长;通过每一层土工格栅上受力最大点的连线,可得出地震荷载作用下的潜在滑裂面。通过理论计算结果与模拟结果做对比,发现两者数值基本接近。研究为高陡坡土工格栅土堤坑抗震设计提供理论依据。

In order to study the structural displacement and geogrid stress of geogrid reinforced embankment on high steep slope at any time and any height under the action of different seismic waves,taking a geogrid reinforced embankment project on high steep slope as the research object,considering the main factors affecting the structural displacement and stress of reinforcement,the definition of thickness-height ratio is proposed.The displacement,acceleration and amplification factor of the geogrid reinforced embankment on high steep slope with different fill thicknesses at the same height under the action of seismic wave,as well as the calculation method of the stress of the reinforcement of the structure at any height and displacement are analysed.The result shows that(1)The smaller the thickness-height ratio of geogrid reinforced embankment on high steep slope,the more the seismic energy dissipated by the structure is,the better the seismic resistance,conversely,the worse the seismic resistance.(2)The larger the thickness-height ratio,the greater the displacement and geogrid stress under the earthquake acceleration,conversely,the smaller the displacement and geogrid stress.(3)With the increase of seismic acceleration and thick-height ratio,the maximum axial force of geogrid element increases in a quadratic mode,and the axial force of the geogrid decreases linearly from the top to the bottom of each layer of fill center.The axial force of geogrid near the filling center decreases linearly from top to bottom.(4)The horizontal displacements of the embankment with different thickness-height ratios under different seismic accelerations present a nonlinear growth pattern,and the displacement at the center of each fill layer presents a quadratic growth pattern from top to bottom.(5)By connecting the maximum stress point on each layer of geogrid,the potential sliding crack surface under earthquake load can be obtained.By comparing the theoretical calculation result with the simulation result,it is found that the 2 values are basically close to each other.The study provides a theroretical basis for seisimic design of high steep geogrid reinforced earth embankment.