铁路穿越盐矿采空区岩体稳定性有限元分析

Finite element analysis of stability of stope rockmass of salt mine area through which railway passes

沪汉蓉铁路通道下辛店镇至云梦间分别有3个主要线路预选方案,其中小取直方案和既有线改建方案的部分地段将位于大规模的盐溶空腔之上或近处的地表,盐溶空腔的时空效应有可能对线路其下地质体的稳定性产生不利的影响。为了正确地选择线路方案,应对所涉及的盐溶空腔区域的力学动态进行定量的研究。为此,笔者就小取直方案穿行的B52矿区、沿既有线改建方案穿行的B63矿区的典型剖面,对相应的岩体稳定性进行了二维及三维弹塑性有限元计算,得出了地层中的位移分布及塑性区,重点分析了盐溶空腔顶部地表及路堤的下沉,最后以铁道线路路堤的允许下沉值为控制指标,给出了可供决策的结论。

There are three main forward selection schemes of line for the Xiaxindian-Yunmeng section of the Shanghai-Wuhan- Chengdu Railway, in which some parts would be located on the earth surface under which there are big salt stoped-out cavities for the scheme of small straight line and the scheme of reconstructing along the old line. The effects of time and space of the salt cavities would produce a harmful influence on the stability of the rockmasses on which the railway will be built. In order to select the right line scheme, the mechanical state of the concerned areas with salt stoped-out cavities should be studied quantitatively. So the 2D and 3D elastoplastic finite element computations are carded out for the stability of the relative rock masses against the typical sections of B52 and B63 mine areas through which the railway might pass; and the displacement distributions and plastic zones in the strata are obtained; and the settlements of the earth surfaces over the salt stoped-out cavities and the embankments are analyzed emphatically. Finally, the conclusions which could be used for the decision of line scheme are given taking the allowable settlement values of railway embankment as the control targets.