水平排水砂垫层对天然地基固结效率影响分析

针对天然地基上的水平排水砂垫层,结合地基土体的渗透系数和厚度,综合考虑砂垫层的渗透系数、宽度和厚度对地基固结的影响,采用平面应变有限元方法,通过参数分析,研究砂垫层与地基参数共同作用对地基固结效率的影响,并采用砂垫层与地基的集总参数,分析其与地基固结效率之间的关系。结果表明:现行规范对于天然地基上砂垫层渗透系数的要求偏于保守;地基固结效率随集总参数的增大呈双曲线形非线性增加,且存在一个集总参数值,可以满足最优固结效率要求并可作为设计控制指标,用于不同地基土质条件下砂垫层的设计计算依据。

Effect of horizontal sand drainage cushion on consolidation efficiency of natural ground

With regard to a horizontal sand drainage cushion on natural ground, a parameter study using the plane strain finite element method was carried out to investigate the effects of the parameters of the sand cushion and ground on the efficiency of ground consolidation. The influences of the permeability, thickness, and width of the sand cushion on ground consolidation were considered, together with the permeability and thickness of ground soil. Meanwhile, a lumped parameter for the sand cushion and ground soil was adopted, and its relationship with the ground consolidation efficiency was analyzed. It was found that the permeability of the sand cushion on natural ground required by the existing technical specification was unreasonable. The ground consolidation efficiency increases nonlinearly, in a hyperbolic manner, with the lumped parameter. There exists a certain value of the lumped parameter that can meet the requirements of optimum consolidation efficiency. This value can be used as a controlling index for designing a sand cushion on the ground with various soil conditions.