Abstract

The purpose of this paper is to investigate the acceleration of consolidation through a new method composed by a cylindrical cavity expansion (CCE) combined with vertical drains (VD). In fact, the cylindrical cavity applies a radial displacement in the soil. Excess pore pressures will be consequently generated and the consolidation process will occur at the vicinity of the cavity wall. The dissipation of excess pore pressures can be enhanced in presence of VD installed at a radial distance r_d from the center of the cylindrical cavity. During cavity expansion, the variation of excess pore pressures and incremental stresses are analyzed. The subsequent consolidation around the CCE in the presence of VD is solved using the Finite Difference Method (FDM) with taking into account the effect of the CCE installation. This effect is described by a decrease in horizontal permeability within a disturbed zone. Obtained results show that the proposed system of consolidation i.e., composed by a CCE combined with VD, greatly accelerates the consolidation of soil. Furthermore, the effects of the extent of the disturbed zone and the soil permeability reduction have a significant influence on the consolidation of the soil. The application of the proposed method to the case of “Tunis Rades La Goulette Bridge” is presented and discussed.

摘要

本文的目的是通过一种由圆柱形空腔膨胀 (CCE) 与垂直排水管 (VD) 组合而成的新方法来研究固结的加速。事实上，圆柱形空腔在土壤中施加径向位移。因此会产生超孔隙水压力，并在空腔壁附近发生固结过程。安装在径向距离r _{d处的 VD 可以增强超孔隙压力的消散}从圆柱腔的中心。在空腔膨胀过程中，分析了超孔隙压力和增量应力的变化。考虑到 CCE 安装的影响，使用有限差分法 (FDM) 解决了在存在 VD 的情况下围绕 CCE 的后续合并。这种影响通过扰动区域内水平渗透率的降低来描述。获得的结果表明，所提出的固结系统，即由CCE 与VD 组合而成，极大地加速了土壤的固结。此外，扰动区范围和土壤渗透性降低的影响对土壤的固结有显着影响。提出并讨论了该方法在“Tunis Rades La Goulette Bridge”案例中的应用。