巷道围岩再造承载层机理及数值模拟

Mechanism and numerical simulation of renewable bearing stratum in roadway surrounding rock

在分析大变形巷道基本支护系统基础上,依据应力转移与强抗承载的围岩稳定思想,提出了巷道围岩再造承载层机理,建立了巷道围岩再造承载层稳定性力学模型,分析了巷道围岩再造承载层的稳定因素,最后进行了数值模拟。结果表明:巷道基本支护系统的承载能力与作用范围有限,基本支护系统作用下巷道浅部围岩呈"O"形整体收敛,弹塑性界面离层明显;而巷道两帮再造承载层与基本支护系统形成"Ω"形承载结构体,整体承载能力加强,顶板应力由底板深部转移改变为向两帮外伸移动,两帮围岩移动由巷道内收敛改变为向巷道底角外扩散,巷道围岩稳定性提高;巷道围岩再造承载层位置越高、长度越大,围岩越稳定;无支护巷道两帮垂直应力集中区明显,支护后巷道两帮垂直应力集中区得到弱化,浅部围岩形成"Ω"承载拱形体,两帮与顶板位移变化量较小,底鼓量为无支护巷道的84.65%,应进一步做好底鼓控制,围岩整体收敛变形较小,支护效果明显。

Based on the analysis of basic support system in large deformation roadway and the principle of surrounding rock stability in stress transfer and strong anti- bearing,the theory on renewable bearing stratum in roadway surrounding rock was presented. A steady mechanics model of renewable bearing stratum in roadway surrounding rock was established,and the stability factors of renewable bearing stratum were analyzed,then the numerical simulation was implemented. The results showed that the bearing capacity and action range of basic support system in roadway were limited. An O- type integral convergence appeared and the elastic- plastic interface separated obviously in shallow surrounding rock of roadway under the basic support system. A Ω- type bearing structure appeared in renewable bearing stratum and basic support system on both sides of roadway,the integral bearing capacity increased,the roof stress changed from deep floor transition into overhanging movement to both sides,and the movement of surrounding rock on both sides changed from convergence in roadway into spread to outside of roadway base angle,so the stability of roadway surrounding rock increased. The higher the position and the larger the length of renewable bearing stratum in roadway surrounding rock,the more stable the surrounding rock. The vertical stress concentration region on both sides was obvious in non- support roadway and was weakened after supporting.The Ω- type bearing arch body was formed in shallow surrounding rock of roadway,and the displacement variation on both sides and roof was smaller,while the floor heave was 84. 65% of that in non- support roadway. The floor heave control should be implemented well,the integral convergence deformation of surrounding rock will be smaller,and the support effect will be obvious.