塑料排水板处理地基非线性固结计算研究

Research on nonlinear consolidation calculation of foundation treated with prefabricated vertical drains

针对目前国内外竖井地基非线性固结计算大多均采用近似等效法求解的不足,根据软土固结理论及数学理论推导,基于塑料排水板椭圆柱假定,推导了考虑地基土水平渗透系数、压缩模量随固结过程非线性变化影响下的排水板处理地基非线性固结控制方程,并利用数学中非线性微分方程理论,给出了非线性固结解析解。通过与Indraratna等非线性固结近似解对比分析,认为理想井下预压荷载越大(Nu越大),则Indraratna等近似法成果误差越大;且在Cc/Ck=1.8、Nu=5时Indraratna等近似解与该理想井非线性固结精确解析解误差高达16%,而解析解与精确数值解基本一致。最后通过Indraratna等典型工程案例验证分析,认为所得理论更符合工程实际,具有较好的工程应用价值。

Considering the deficiency of the nonlinear consolidation calculations of vertical drains foundations solved by approximate equivalent method, and based on the assumption of plastic drainage plate elliptical column, the horizontal permeability coefficient and compression of foundation soil are deduced using the soft soil consolidation theory. An analytical solution for the nonlinear consolidation is given by the nonlinear differential equation theory, which considered the drainage plate under the influence of compressive modulus with nonlinear variation of the consolidation process. By comparing with the results in Indraratna(2005), it is considered that the larger the ideal vertical drains foundations preload load(the larger Nu) is, the greater the error obtained by the approximation method in Indraratna et al.(2005), and this error can be up to 16% compared with the results in this paper when the Cc/Ck=1.8 and Nu=5. The results reveal that the analytical solution proposed in this paper is aligned with the exact numerical solution, and the theory suggested is more effective in engineering application.