考虑径向渗透系数变化的真空预压竖井地基固结解析解

Analytical solution for consolidation of vertical drain under vacuum preloading considering the variation of radial permeability coefficient

针对真空预压条件下竖井地基固结问题,考虑竖井地基扰动区土体径向渗透系数变化的3种模式(扰动区渗透系数为常数、线性变化、抛物线变化)和竖井井阻随时间变化等因素影响;建立数学计算模型,采用解析解法,推导了考虑径向渗透系数因施工扰动而变化的真空预压竖井地基固结问题的解析解。基于此解,编制了计算程序,绘制出了考虑扰动区土体径向渗透系数变化和竖井井阻随时间变化影响的真空预压竖井地基固结曲线图。研究表明:井阻变化率对固结速率有较大影响;在土体扰动区径向渗透系数变化的3种模式中,渗透系数为抛物线变化时固结速率最快,渗透系数为线性时次之,渗透系数为常数时固结速率最慢。

To solve the consolidation problem of vertical drains under vacuum preloading, this study mainly considers three types of radial permeability coefficient of soil(including the constant distribution pattern, the linear distribution pattern and the parabolic distribution pattern) in the disturbance area and the resistance of vertical drains changing with time. The mathematical model is established. The analytical solution is used to derive the consolidation problem of vertical drains under vacuum preloading considering the variation of radial permeability coefficient due to construction disturbance. Based on this solution, the calculation program is compiled, and the consolidation curve of vertical drain considering the influence of various factors is drawn. The results show that the change rate of drain resistance greatly affects the average consolidation degree. In the three models studied in this paper, the consolidation rate is the fastest when the permeability coefficient shows a parabolic change, while the consolidation rate is the slowest when the permeability coefficient maintains constant.