桩承式加筋路堤三维动力流固耦合分析

3D Dynamic Coupled Mechanical and Hydraulic Analysis of Geogrid-reinforced Pile-supported Embankments

为了研究交通荷载作用下桩承式加筋路堤的动力特性,采用FLAC 3D软件建立了路堤的三维动力流固耦合分析模型,对无筋无桩、有筋无桩、无筋有桩、有筋有桩4种情况的路堤在动荷载作用下的竖向位移、水平位移、桩土应力比、超孔隙水压力、加速度等进行了计算分析,对比研究了4种情况下各自的特点,揭示了桩承式加筋路堤的作用机制。数值分析结果表明:交通荷载作用下,桩承式加筋路堤通过桩体土拱效应和格栅加筋效应的联合作用,其路面竖向位移、差异沉降及路堤堤址的水平位移都比其它几种情况明显减小;桩土应力比在刚开始加载时最大,随后逐渐减小并趋于稳定;软土地基中的加速度幅值及加速度趋于稳定的时间都明显减小;软土地基中的超孔隙水压力值也远小于无筋无桩时的值。

In order to investigate the dynamic behaviors of geogrid-reinforced pile-supported embankments under traffic loading,three-dimensional coupled mechanical and hydraulic numerical simulations are conducted using FLAC 3D.Four cases are studied including unreinforced and no-pile embankments,reinforced embankments,pile-supported embankments,and geogrid-reinforced pile-supported embankments.The behaviors of vertical displacement,horizontal displacement,pile-soil stress ratio,excess pore water pressure and acceleration under four cases are analyzed.It is found that the vertical displacement,nonuniform settlement and horizontal displacement of geogrid-reinforced pile-supported embankments are smaller than those of other cases due to soil arching effect and reinforcement effect.Pile-soil stress ratio decreases with the increase of loading number.The crest value of acceleration and the time for acceleration to be steady are also smaller than those of other cases.The dissipation velocity of excess pore is quicker than that of unreinforced embankments.