地震作用下土工格栅加筋高土石坝的稳定性分析

Stability Analysis of Geogrid Reinforced High Earth-rockfill Dam under Seismic Action

针对拟静力法得到最小安全系数评价边坡稳定性的局限性,通过有限差分软件FLAC 3D的二次开发平台,用FISH语言开发一个安全系数时程的计算方法。建立三维模型,使用修正的Mohr-Coulomb本构模型,通过安全系数时程分析土工格栅加筋高土石坝的坝坡稳定性。改变格栅的材料强度、格栅长度以及格栅的铺设间距等参数,研究格栅参数对安全系数的影响,确定土工格栅的最佳铺设方法。结果表明:动力安全系数时程图不仅可以从时程上分析安全系数,还可以分析坝坡破坏的起始时间;土工格栅弹性模量为2.5 GPa、满铺间距为4 m时加固效果最佳。根据模拟结果提供的土工格栅铺设方法加固双江口堆石坝,对比可研报告,模拟结果与报告规律基本一致,验证土工格栅铺设方法的合理性,模拟效果较好。

Pseudo-static method has some limitations in obtaining the minimum safety factor to evaluate the stability of slope.In view of this,we developed a method for calculating the time-history of safety factor using FISH language through the secondary development platform of the finite-difference software FLAC 3D.Via the modified Mohr-Coulomb constitutive model we simulated the slope stability of geogrid-reinforced high earth-rock dams,and analyzed the slope stability of geogrid-reinforced high earth-rock dams according to the time-history of safety factors.According to the simulation,we obtained the changes of safety factor in the presence of varying geogrid parameters(including material strength,geogrid length,and geogrid spacing),and determined the optimum layout of geogrids.Results demonstrated that we could analyze the time-history of safety factor by the time-history graph of dynamic safety factor,and also analyze the start time of the failure of dam slope.Moreover,the reinforcement effect reaches the optimum when the elastic modulus of geogrid is 2.5 GPa and the spacing of geogrids is 4 m.The simulation results of Shuangjiangkou Rockfill Dam are basically consistent with the results in the feasibility research results.The geogrid layout is proved rational,and the simulation method in the present paper is effective.