含水软岩特大断面巷道交岔点稳定性研究

Study on Junction Stability of Mine Roadway with Ultra Large Cross Section in Water Bearing Soft Rock

为了解决新疆沙吉海矿区侏罗纪含水软岩支护难的问题,在工程地质勘查、理论分析、数值分析、室内试验及现场测试的基础上,采用非线性大变形力学设计方法,研究了特大断面巷道交岔点的变形破坏机理、原因。结果表明:交岔点处的变形机制为中间岩柱失稳+分子吸水膨胀机制+重力机制+水的作用+工程偏应力等因素的复合型变形机制。通过对穿锚杆增加水平约束,改善岩体的受力状态,实现锚杆的双向互控,增强了中间岩柱的整体强度及稳定性;采用恒阻大变形耦合支护可充分释放围岩塑性能,同时又能限制其过大的不利变形。现场监测结果显示:两帮最大移近量为53mm,顶底板最大移近量为34 mm,达到了良好的耦合支护状态,保证了工程的稳定性。

In order to solve the difficult support problem of Jurassic water bearing ultra soft rock in Shajihai Mining Area of Xinjiang,based on the detail engineering geological survey, theoretical analysis, numerical analysis, indoor test and site test and measurement, an nonlinear high deformation mechanics design method was applied to study the deformation failure mechanism and cause of the ultra large cross section junction. The results showed that the deformation mechanism at the junction was a complex deformation mechanism with stability lost in the middle rock pillar, molecule water sucking swelling mechanism, gravity mechanism, water role, engineering deviatoric stress and other factors. With the lateral level restraint added on the bolt support, the stress status of the rock mass was improved, the bidirectional mutual control of the bolt could be realized and the integrated strength of the stability of the middle rock pillar could be enhanced. The constant resistance and high deformation coupling support was applied to fully release the plastic performance of the surrounding rock. Meanwhile over large deformation could be restricted.The monitoring results show that the maximun two sidewalls convergence was 53 mm and the maximum floor-to-roof convergence was 34 mm.Thus the coordinate deformation of the surrounding rock-support could have a good coupling support status and could ensure the engineering stability.