不同围岩支护状态下地下硐室群扩建稳定性分析

Stability Analysis of Underground Gate Group in Extension Project Under Different Support Conditions

地下硐室扩建改造过程中工程岩体稳定性问题是工程勘察领域的重要科学问题,本文以某地下人防工程扩建为工程背景,采用ABAQUS有限元计算软件对无支护状态、锚杆支护状态、回填支护状态、锚杆及回填支护状态四种开挖后支护状态下围岩应力场及位移场演化特征进行了分析研究。研究结果表明:不同状态下二次开挖后位移沉降值最大为0.918mm,主硐室右侧围岩出现塑性区且应力较左侧高约1.5倍;回填部分联络硐室有利于提高硐室群整体稳定性,同时可采用加长锚杆,防控侧壁破坏诱发的围岩整体失稳;Ⅳ类围岩塑性区明显,且较Ⅲ类围岩应力集中系数大,应采取适当加固措施以满足硐室群稳定性要求。

The engineering rock mass stability of underground gate group extension project is an important scientific issue in engineering investigation. Some underground civil defense fortifications was chosen as engineering background. The stress and displacement evolution characteristics were conducted by ABAQUS under four different support conditions (no support state,bolt support state,backfill support state,bolt+backfill support state). The results showed that the maximum subsidence value was 0.918 mm under different support conditions after secondary excavation. The plastic zone appeared in the right side of main gate,and the stress level was1.5 times higher than that of the left side. The connection gates backfill was beneficial to the entire stability of the gate groups. The lengthening bolt was used to prevent the surrounding rock instability induced by lateral wall failure. The plastic zone of Ⅳ surrounding rock was obvious,and the stress concentration factor was bigger than Ⅲ surrounding rock. The reinforcement measures should be conducted to satisfy the gate stability.