软弱缓倾层状隧道围岩变形破裂规律试验研究

Experimental Investigation on the Law of Deformation and Fracture of Surrounding Rock of Soft and Gently Inclined Layered Tunnel

针对软弱缓倾层状隧道围岩变形与破裂规律的热点问题,利用基于电机双轴加载的中小型隧道物理模拟试验系统和精细化岩土数字照相量测系统PhotoInfor,对软弱缓倾层状隧道围岩变形与破裂规律进行试验研究。结果表明:隧道左拱肩位置处围岩先形成剪切楔并塌落,随后左拱腰位置处围岩继续破坏并向围岩深部发展,形成新的剪切楔体,使围岩变形破裂呈明显左右不对称状;此类软弱缓倾层状隧道围岩松动圈厚度呈左大右小不均衡分布规律,并对此提出差异化支护建议,在优化提高隧道围岩稳定性同时也可节约施工成本;通过数字照相量测技术,全过程、定量化地获得了隧道洞周围岩位移变化情况,其位移变化情况与围岩宏观破坏过程基本保持一致。

Aiming at the hot issue of the deformation and fracture law of the surrounding rock of soft and gently inclined layered tunnel,the deformation and fracture law of the surrounding rock of soft and gently inclined layered tunnel is experimentally studied using the physical simulation test system of small and medium-sized tunnel based on motor biaxial loading and the refinement digital photogrammetric measurement system named PhotoInfor.The results show that:The surrounding rock at the left spandrel of the soft and gently inclined layered tunnel forms a shear wedge and collapses first,and then fracture occurs in the surrounding rock at the left spandrel and continued to the deep part of the surrounding rock,forming a new shear wedge,which makes the deformation and fracture of the surrounding rock appear obvious left-right asymmetry;The thickness of the broken rock zone of the surrounding rock of this kind of soft and gently inclined layered tunnel is unevenly distributed from left to right,and the differential support suggestions are put forward,which can optimize and improve the stability of the surrounding rock of the tunnel and save the construction cost at the same time;Through the digital photogrammetric measurement technology,the change of surrounding rock displacement around the tunnel is obtained quantitatively in the whole process of the test.The displacement development condition is basically consistent with the macro failure process of surrounding rock.