膨胀土地区下伏中浅层采空区地基稳定性评价

Stability Evaluation of Foundation in Underlying Middle-shallow Goaf in Expansive Soil Area

以南宁外环高速公路中一段处于膨胀土地区的小煤窑采空区为工程依托,建立有限差分网格模型,定量求算出煤层充分采动后地表最大移动变形值;采用了抚顺矿区分析下沉随时间变化的建议公式求得该采空区地表剩余变形量;最后,对该路段地基进行稳定性评价。结果表明:采空区处于不稳定状态,必须对该路段的地基进行有效处治,才能保证新建高速公路该路段的工程质量。

Taking the mined-out area of small coal mines in the expansive soil section of Nanning outer-ring expressway as the background, a finite difference grid model was established to solve the quantitative value of maximum surface deformation after full mining of coal seam; the formula advised in the analysis on the settlement of Fushun mining area changed with time was used to get the residual deformation of the surface in this goaf; finally, the stability of foundation in this section was evaluated. The result shows that the goaf is instable, thus the foundation therein must be treated to ensure the engineering quality of highway newly built in this section.