深部多裂隙岩体开挖变形破坏规律模型试验研究

Model tests on deformation and failure laws in excavation of deep rock mass with multiple fracture sets

深部资源开发中地下洞室围岩稳定控制必须面对峰后碎裂岩体的变形和破坏问题,目前深部多裂隙岩体开挖强卸荷引起的围岩变形破坏规律尚不清楚,常导致大体积塌方、大变形等重大工程事故。采用大尺度三维模型相似试验系统,分析具有一定倾角的多组裂隙的岩体在高地应力下开挖变形破坏规律。试验结果表明:隧道上下侧围岩主要呈现大变形现象,左右侧围岩呈现分层破裂现象,破裂区随时间增长由内向外逐渐增多,在拱顶、底板大变形的诱导下发生边墙大体积坍塌;隧道围岩由内向外位移值和应力值呈现波动状分布;裂隙倾角与破坏区分布形态有一定相关性。为保障深部工程的安全兴建与运营提供了试验基础。

The stability of surrounding rock of underground caverns in development of deep resources must face deformation and failure problems of post-peak fractured rock. At present, the deformation and failure laws of the surrounding rock of deep fractured rock mass in strong unloading excavation are unclear, often leading to large volume collapse, large deformation and other major engineering accidents. Using a large scale three-dimensional similar model test system, the deformation and failure laws in excavation of deep rock mass with multiple fracture sets and certain tilt angle under high ground stress are analyzed. The results show that the surrounding rock at the upper and lower sides mainly presents large deformation phenomenon, the rock at the left and right sides exhibits layered fracture phenomenon, and the fracture area increases from the inside to the outside with time. Large volume of side wall collapse is induced by the large deformation of vault and floor. The displacements and stresses of the surrounding rock from the inside to the outside are fluctuant. There is a great correlation between the fracture angle and the distribution of failure zone. The results may provide more experimental data for ensuring the safety of construction and operation of deep under-ground engineering.