膨胀土中EPS缓冲层-悬臂式挡墙支护结构的受力变形数值模拟

针对膨胀土中墙后铺设聚苯乙烯泡沫(EPS)缓冲层的悬臂式挡墙,探究了膨胀土因降雨入渗产生膨胀时EPS缓冲层的减压效果。对南阳中膨胀土开展膨胀特性试验,确定其在侧限和竖向荷载作用下的膨胀系数;在此基础上,利用ABAQUS数值软件对膨胀土-EPS缓冲层-悬臂式挡墙体系开展数值分析,研究了EPS缓冲层的厚度与弹性模量及与墙体和膨胀土间摩擦对该支护结构受力变形特征的影响规律。结果表明:EPS缓冲层能有效减小悬臂式挡墙上的侧压力并改变墙背土压力的分布;厚度较厚、弹性模量较低的EPS缓冲层减载效果更好;EPS缓冲层与墙体、膨胀土之间的摩擦影响墙背侧压力的分布,但不影响侧压力的合力大小;EPS缓冲层的压缩刚度与其减载性能成反比。

Numerical Simulation of the Force and Deformation Characteristics of Cantilever Retaining Structure with EPS Buffer in Expansive Soil

The decompression effect of expanded polystyrene (EPS) buffer layer in cantilever retaining wall was examined when the expansive soil expands due to rainfall infiltration. The expansion characteristics of Nanyang expansive soil were tested to determine its expansion coefficient under lateral and vertical loads. On this basis, the expansive soil-EPS buffer layer-cantilever retaining wall system was numerically simulated using ABAQUS to explore the influences of EPS buffer layer (thickness, elastic modulus, and interface friction) on the stress and deformation of the system. Numerical results indicate that EPS buffer layer effectively reduces the lateral pressure on the cantilever retaining wall and changes the distribution of soil pressure on the wall back. The EPS buffer layer with larger thickness and lower elastic modulus has better effect. The friction between EPS buffer layer, wall and expansive soil affects the distribution of lateral pressure on the wall, but does not affect the resultant force of the lateral pressure. In addition, the compression stiffness of EPS buffer layer is inversely proportional to its load reduction performance.