成层竖向排水井地基固结分析

Analysis of consolidation of layered ground with vertical drain

实际工程中竖井地基具有成层性,有时竖井也并未完全打穿软土层。在竖井打设区满足竖井等应变固结理论、下卧层满足一维太沙基固结理论假设的基础上,将现有竖井地基固结理论推广到成层未打穿竖井地基情况。利用边界条件和竖直向连续条件,确定该系统的正交关系,并给出了其固结解答,该解具有广泛的适用性。通过对竖井打设区和下卧层层数的变化,即可获得现有关于简单未打穿竖井地基的固结解答。将该解答编制成应用程序,对一算例进行了分析。结果表明,平均固结度按孔压定义和按变形定义是不相同的,硬表层的存在会加快其下土层的固结。

In engineering practice, the subsoil with vertical drains is often composed of multi-layer strata and the subsoil is partially penetrated by vertical drain wells. Based on the assumptions that the section with vertical drains satisfies equal strain condition and the section without vertical drains satisfies Terzaghi's one dimensional consolidation theory, the existing simplified consolidation theory of ground with partially penetrated vertical drain wells is developed so that multi-layer subsoil can be take into account. The orthogonal relation of the system is obtained using the boundary conditions and continuity conditions in vertical direction. The consolidation solutions of the system is presented. The solution has comprehensive applicability. The existing consolidation solutions of simplified ground with partially penetrated vertical drain wells can be obtained by changing the number of the stratum of the section with vertical drain wells and the section without it. The solution has been coded into a program and a case is analyzed using it. Analysis shows that the average degree of consolidation of the system defined by pore pressure is different from that defined by settlement. It also shows that existence of crust can accelerate the consolidation of the stratum.