1. State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology,Qingdao　266590,China;2. College of Mining and Safety Engineering,Shandong University of Science and Technology,Qingdao　 266590,China;3. College of Civil En-gineering and Architecture,Shandong University of Science and Technology,Qingdao　 266590,China

考虑围岩应力释放,采用叠加原理将厚软岩层巷道全断面锚固模型分解为锚固前的初始状态模型和锚固后的增量模型2种子模型。基于无锚杆时模型的拉梅解和锚杆影响区模型对2种子模型下围岩的力学量进行了解析,叠加后得到了原模型下锚固围岩的力学解。解析结果表明,锚固区围岩的径向应力大幅度提高,有利于形成承载拱,但切向应力变化不大,在非锚固区,围岩的应力解与无锚杆时的拉梅解相同,锚固后巷道位移明显的减少,尤以锚固区位移变化最显著。基于以上特点,利用锚固前后锚固区内围岩应力、位移的相对变化量定义了锚固效应的3个量化指标,并进一步讨论了围岩弹性模量和锚杆预应力的影响,结果表明锚固对软弱围岩的力学量改变比对硬岩更加显著。最后针对锚固对围岩塑性区的控制作用,建立了支护参数和围岩弹塑性状态的函数关系,并分析了不同强度围岩处于弹性状态的临界支护参数。

The pressure arching effect of rock bolt on weakly cemented soft rock should be strengthened in China west- ern mining area instead of suspending action,so it is better to increase the supporting density rather than increase the length of rock bolt. Based on the idea above,a mechanical model of full section anchoring in thick weakly cemented soft rock tunnel was established. Considering the stress release of surrounding rock,the model was decomposed into two sub-models by employing the superposition principle:one is the initial state model before anchoring,and the other is the enhance model after anchoring. Then,the analytical solutions of mechanical responses of surrounding rock in the two models were derived based on Lame’s solution and bolt model,and the solutions of the original model were estab- lished. The analytical results show that the radial stress in anchorage zone is greatly improved,which is beneficial to construct the load-bearing arch. However,the tangential stress remains stable. In the non-anchorage zone,the stress so- lutions are the same with Lame’s solution without rock bolt. Displacement in surrounding rock decreases significantly especially in the anchorage zone. According to the above conclusions,three quantitative indexes to quantify the anchoring effect were defined by the relative variation of responses in surrounding rock before and after bolting,and then the effect of elastic modulus of rock mass and pre-stress in rock bolt were discussed in detail. Results show that the me- chanical responses in soft rock are changed more significantly than those in hard rock. Finally,the functional relation- ship between the support parameter and elastic-plastic state of surrounding rock was determined and the critical sup- port values to maintain the rock mass with different strengths in elastic stage were calculated.

国家自然科学基金资助项目(41472280)；山东省优秀中青年科学家科研奖励基金资助项目(BS2015SF005)；山东科技大学青年教师教学拔尖人才培养计划资助项目；

Zhao Zenghui,Wang Weiming,Tan Yunliang,et al. Quantitative model of full section anchoring in thick soft rock tunnel[ J]. Journal of China Coal Society,2016,41(7):1643-1650.