劣胶结泥砂岩巷道变形机理及返修控制技术

Deformation Mechanism and Repair Control Technology of Roadway in Weakly Consolidated Mud-sand Stone

劣胶结泥砂岩互层岩体具有岩层薄、胶结劣、开挖扰动剧烈、持续变形量大等工程特性,极易引起巷道顶沉底臌、两帮内挤等流变破坏。以榆树井2~#煤主运大巷为背景,应用现场位移监测、地质雷达探测、电镜微观扫描以及地应力测试等技术手段,揭示了榆树井矿区劣胶结围岩的矿压特性,并深入分析了泥砂岩互层巷道的变形破坏机制;在此基础上,提出了"初期恒阻让压、中期预留变形、后期刚性加固"的刚柔耦合返修控制思路,给出了巷道结构的支护优化措施,工程实践后的监测结果表明,采用初期柔性、后期封闭的刚柔联合方案可以确保将劣胶结泥砂岩巷道的围岩变形控制在较低水平,使支护体系与周边围岩共同作用构成承力整体,确保了围岩与巷道结构的长期稳定与安全。

The inter layer rock mass of weakly consolidated mud-sand stone has the engineering characteristics such as small thickness, poor cementation, serious excavation disturbances, and large deformation, which are easy to cause large deforma-tion and long duration of the roadway. Taking the main haulage of 2^# seam in Yushu-Jing mine as a background, the pressure behavior characteristics of the surrounding rock were revealed, by the methods of on-sile monitoring, geological radar detec-tion, electron microscopic scanning and in-situ stress testing. And then the deformation and failure mechanism of roadway in weakly consolidated mud-sand stone was analyzed in depth. On this basis, a joint control measurement of ＂constant bearing and release-pressure in the early, reserving deformation in the medium term, rigid reinforcement in the late＂ was presented and ap-plied into practice. The monitoring results after the engineering practice showed that, the joint rigid-flexible support scheme that adopting flexible support in the early and enclosed support in the late could ensure to control the roadway deformation in the low level, prompt the supporting system and the surrounding rock combined to form a hearing force, and guarantee the long-term stability and safety of surrounding rock and roadway structure.