不同沿空留巷开采工艺比选研究及工程应用

沿空留巷工艺决定着煤矿的回采效率及经济收益,以沙曲煤矿4303工作面为工程背景,对充填沿空留巷、切顶沿空留巷和充填体外切顶沿空留巷三种留巷工艺进行比选研究。首先,采用位移变分法对比分析了三种不同沿空留巷方式的顶板下沉量。其次,运用FLAC^(3D)数值模拟软件建立了不同沿空留巷方式计算模型,分析了三种留巷方式下煤帮侧向支承应力及围岩变形规律。结果表明:(1)对于侧向支承应力:充填体外切顶沿空留巷<切顶沿空留巷<充填沿空留巷;(2)与充填沿空留巷相比,切顶沿空留巷的顶板下沉量与底鼓量分别降低了14.3%、16%,充填体外切顶沿空留巷的顶板下沉量与底鼓量分别降低了23.8%、12%;(3)对于留巷成本:充填沿空留巷和切顶沿空留巷相近,充填体外切顶沿空留巷成本最高。最后,将切顶沿空留巷在沙曲煤矿4303工作面进行了应用,取得了良好的应用效果。

Frictional contact algorithm study on the numerical simulation of large deformations in deep soft rock tunnels

There exist three types of nonlinear problems in large deformation processes of deep softrock engineering, i.e., nonlinearity caused by material, geometrical and contact boundary. In this paper, the numerical method to tackle the nonlinear contact and large deformation problem in A Software on Large Deformation Analysis for Soft Rock Engineering at Great Depth was presented. In the software, based on Lagrange multiplier method and Coulomb friction law, kinematic constraints on contact boundaries were introduced in functional function, and the finite element equations was established for two incremental large deformation analyses models, polar decomposition model and additive decomposition model. For every incremental loading step, by searching for the contact points in the potential contact interfaces (the excavation boundaries), the Lagrange multipliers, i.e., contact forces are calculated iteratively by Gauss-Seidel method, and justified through satisfy the inequalities of static constraint on contact boundaries. With the software, large deformation and frictional contact of a transport roadway were analyzed numerically by the two models. The numerical examples demonstrated the efficiency of the method used in the software.

地铁联络通道冻结区域力学特性分析

以上海市轨道交通5号线延伸工程盾构隧道联络通道冻结工程为依托,针对双线盾构隧道与联络通道和泵房组成的复杂空间结构,对冻结区域力学特性,采用PKPM进行理论分析;采用FLAC3D构建三维数值模型,进行数值模拟分析。结果表明,联络通道及泵房冻结施工阶段,冻结区域的应力安全系数满足规程要求,处于安全状态。