淋水条件下弱胶结软岩巷道变形破坏特征与支护技术

Deformation failure characteristics and support technology of weakly cemented soft rock roadway under water spraying condition

为研究淋水条件下弱胶结软岩巷道合理的支护技术,以色连二矿12307回风巷为背景,考虑弱胶结砂质泥岩强度和体积随淋水时间的变化,对其在"锚带网索梁"支护条件下的应力、变形以及塑性区变化特征展开数值模拟研究,并提出了支护改进措施。研究结果表明:"锚带网索梁"支护条件下,受淋水影响,弱胶结软岩巷道围岩径向位移将随着巷道向前掘进而呈指数衰减方式持续增长,最终其顶底板、两帮移近量将分别达750、200 mm;进行"增加锚杆长度、改金属网为钢筋网喷射混凝土、顶板以及两帮进行锚索加强"支护改进后,弱胶结软岩巷道围岩径向位移最大仅为29.0 mm,而塑性区破坏深度则都基本稳定为3.0 m,有效地保证了巷道安全。

In order to study the reasonable support technology of weakly cemented soft rock roadway under water spraying condition,the 12307 return airway of Selian No.2 mine was taken as the background.The stress,deformation and plastic zone change characteristics of roadway surrounding under the condition of“anchor belt net and cable beam”support were studied by considering the strength and volume change of weakly cemented sandy mudstone with water spraying time,and the several improvement measures for support plan were proposed.The results of the study show that:under the condition of“anchor belt net and cable beam”,the surrounding rock radial displacement of weakly cemented soft rock roadway will continue to increase exponentially under the influence of water spraying.Finally,its moving distance from roof to floor and two sides will reach 750 mm and 200 mm respectively.After the improved support of“increasing the length of anchor bar,changing metal mesh to reinforced mesh sprayed concrete,and strengthening the support of roadway roof and two sides with anchor ropes”,the surrounding rock maximum radial displacement of weakly cemented soft rock roadway is only 29.0 mm,and the failure plastic zone depth is basically stable at 3.0 m,which well guarantees the safety of the roadway.