线性加载下含砂垫层地基固结分析

针对含水平排水砂垫层地基的固结问题,建立了线性加载下夹砂垫层地基的二维固结模型,并通过边界转换法、积分变换法给出了相应的半解析解。在通过对解答的退化以及数值法验证半解析解正确性的基础上,分析了砂垫层与地基土的几何及物理参数对地基固结的影响。研究表明:对于地基土,地基固结速率随土体水平渗透系数增大而提高,随地基宽度的增大而降低;对于砂垫层,固结速率随砂垫层厚度、水平渗透系数的增大而提高;对于外荷载,加荷速率越快,孔压达到峰值所需时间也越短,地基固结速率亦随之提高。此外,以地基顶面砂垫层为例,综合考虑砂垫层的渗透系数与厚度对砂垫层透水性的影响,当组合参数h_Tk_Th/lk_v≥200时(h_T、k_Th、 l、k_v分别为砂垫层厚度、水平渗透系数、土体宽度和竖向渗透系数),砂垫层近似为完全排水边界。

Consolidation analysis of foundation with sand blankets under ramp loading

Aiming at the consolidation of foundation with the horizontal sand blankets, a two-dimensional consolidation model under ramp loading was established, and the corresponding semi-analytical solution was obtained using boundary transform method. Based on this solution, the effects of geometric and physical parameters of sand blankets and ground soil on the consolidation subjected to ramp loading was analyzed. The results show that the consolidation rate increases with the increase of horizontal permeability coefficient but decreases with the increase of foundation width for the soil. For sand blankets, the consolidation rate increases with the increase of sand blankets thickness and horizontal permeability coefficient. In addition, for the external loads, the faster the loading rate, the shorter the time required for the pore pressure to reach the peak value, and the higher the consolidation rate of the foundation. Lastly, the influence of horizontal permeability coefficient and thickness on the permeability of the sand blankets was considered comprehensively. When the boundary condition of the interface of sand blanket and soil foundation is close to the full drainage boundary condition, the parameter needs to be greater than 200 ( is the thickness of the sand blankets, and is the horizontal permeability coefficient of the sand blankets, is the width of soil foundation, and is the vertical permeability coefficient of soil foundation).