摘要
为了研究不同覆跨比条件下浅埋软弱隧道围岩的破坏模式,通过室内模型试验对隧道围岩破坏的过程进行模拟;利用强度折减法原理对模型试验进行有限差分数值验证,得出了二者基本一致的结论;通过对模型试验与数值模拟结果的分析,推导基于岩柱理论的修正算法。研究结果表明:浅埋软弱隧道围岩的破坏最早从拱顶开始,由于拱顶塌落区的形成,拱顶两边产生类似滑坡的塌落效应,即浅埋破碎围岩隧道的"二阶段"破坏;当覆跨比较小时,围岩的自承能力弱,围岩塌落速度快,塌落体积少,形成塌穿型塌方;当覆跨比为3.0时,形成了浅埋压力拱,破坏已不能到达地表;当覆跨比为2.5时,围岩塌落形成的塌落体体积及破裂区影响区域最大,施工时支护应及时,保证其安全。
To analyze the failure mode of shallow-buried weak tunnel surrounding rock at different thickness-span ratios, the failure process was studies through a number of model tests. The results of model tests were verified by means of finite difference numerical simulation using the theory of strength reduction method, and a basic consistent conclusion was obtained. Through the analysis of numerical simulation and model test results, a modified method based on the theory of rock pillars was derived. The result shows that the failure zone of shallow-buried weak tunnel surrounding rock initiates from arch crown of tunnel. Due to the damage zone of arch crown formation, the damage effect of similar landslide, namely ‘two stage＇ failure of shallow-buried weak tunnel surrounding rock, develops on both sides of arch crown. When the thickness-span ratio is relatively small, with high speed of collapse and small volume of rock collapse, the self-supporting capability of surrounding rock is weak. Hence the caving collapse occurs. When the thickness-span ratio equals 3.0, the failure zone of the surrounding rock which forms a shallow-buried pressure arch can not reach the surface. When the thickness-span ratio equals 2.5, the volume of surrounding rock collapse and the influence of failure zone is the largest. In order to ensure the safety, tunnel support should be done timely during construction.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2016年第5期1744-1751,共8页
Journal of Central South University:Science and Technology
基金
煤矿灾害动力学与控制国家重点实验室自主研究课题(2011DA105287-MS201208)
中央高校基本科研业务费专项资金资助项目(CDJXS12 20 11 06)~~
关键词
浅埋隧道
软弱围岩
覆跨比
破坏模式
岩柱理论
shallow-buried tunnel
weak surrounding rock
thickness-span ratio
failure mode
rock pillars theory
