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针对大变形巷道顶板支护系统中锚杆与锚索受力和变形不协调的问题,研发了一种新型可接长锚杆。在对普通锚杆、锚索及新型可接长锚杆拉伸试验和力学分析的基础上,结合大变形巷道顶板围岩的变形破坏特征,提出了大变形巷道顶板可接长锚杆耦合支护系统,建立并分析了可接长锚杆耦合支护系统与锚索耦合支护系统的本构模型。研究表明:当巷道顶板变形量超过锚索最大延伸量时,锚索耦合支护系统中锚索由于延伸率低,过早于普通锚杆达到延伸极限而破断,而可接长锚杆能与普通锚杆在受力和变形2方面协调同步地支护顶板围岩;可接长锚杆能够提高顶板围岩的自承性能,并在保证较强支护力的同时提供更大的让压距离。可接长锚杆耦合支护系统成功应用于赵固一矿11031巷道试验段中,顶板变形量比原支护方案减少了20%左右,顶板围岩从开挖到稳定的时间缩短了33%,且顶板变形稳定后顶板下沉速率较原支护方案明显降低。
Aiming at the problem of the unbearable stress and deformation of anchor bar and anchor cable in roof support system of large deformation roadway, a new type of extendable anchor rod is developed. Based on the tensile test and mechanical analysis of ordinary anchor, anchor cable and new extendable anchor rod, combined with the deformation and failure characteristics of the surrounding rock of roof of large deformation tunnel, The system is established and analyzed. The constitutive model of the coupling support system with anchor and cable can be established and analyzed. The results show that: when the roof deformation exceeds the maximum extension of the cable, the anchoring cable in the cable anchoring support system breaks down due to the low elongation, premature reaching the extension limit of the common anchor, The common anchor rod supports the surrounding rock of the roof in coordination and synchronously with respect to the stress and the deformation. The extendable anchor rod can improve the self-bearing performance of the roof rock and provide a greater allowable pressure distance while ensuring strong support force . The long bolt-supported supporting system can be successfully applied to the test section of 11031 roadway in Zhao Gu Yi No. 1 Mine. The deformation of the roof is reduced by about 20% compared with that of the original support. The time from excavation to stabilization of roof rock is reduced by 33% , And the deformation rate of the roof after the roof sinking rate significantly lower than the original support program.