基于离心模型试验的水泥土搅拌法加固斜坡软弱土地基变形特性分析

Deformation characteristics analysis of slope soft soil foundation treatment with mixed-in-place pile by centrifugal model tests

为充分掌握斜坡软弱土地基在路堤荷载作用下的变形特性,寻求合理的地基加固措施,以新建达成铁路扩能改建工程某工点为原型,设计了5组基于水泥土搅拌法地基处理方案的室内土工离心模型试验。通过对试验数据的整理分析,结果表明:(1)针对斜坡软弱土地基的上、下坡侧分别采取不同的桩间距布设,可减小斜坡软弱土地基沿横向的差异沉降变形,提高地基加固的均匀性;(2)在斜坡软弱土地基的下坡一侧布设斜桩,具有较好的水平变形约束效果,但在竖向沉降控制方面表现略差;(3)斜坡软弱土地基下坡一侧产生的变形将引起上坡一侧产生相同方向的变形,并以水平变形的表现较明显,地基加固应以控制下坡一侧的变形为重点;(4)地基水平变形沿深度的变化规律因地基布桩疏密的不同而表现出先增大后减小的单峰型曲线和单调衰减的双曲线型两种形态。

In order to know well the deformation characteristics of slope soft-soil foundation under the action of embankment loading and find a reasonable foundation treatment measure, taking a special project about reconstruction of newly-built Da-Cheng railway project as a prototype, this paper designs 5 groups centrifugal model tests based on the mixed-in-place pile to deal with the foundation＇s strategies. According to the analysis of the experimental data, the conclusions are drawn as follows. 1） By adopting different pile spaces layout style at the upside and downside directions of the slope, it can reduce the different deformations of the slope soft-soil foundation along the lateral side and improve the uniformity of the foundation treatment. 2） It has better deformation binding effect by setting up the tilted pile in the downhill side of the slope soft-soil foundation; but it has less effective performance in controlling the vertical subsidence. 3） The slope soft soil foundation deformation that appeared at the downhill side will give rise to the same direction deformation at the uphill side, and the horizontal deformation is more obvious. The foundation treatment should put emphasis on the deformation controlling of downhill side. 4）The varying law about horizontal deformation along the depth direction shows para-curve style which is first adding then reducing and hyperbola style that is humdrum reducing, attribute to the density of the pile layout.