某水电站引水隧洞岩爆可能性判别及预测

Possibility analysis of rock burst of diversion tunnel of a hydropower station and forecast

新疆某水电站引水隧洞开挖中发生多次应变型零星岩爆,主要表现为劈裂破坏后成层剥落,给工程建设和人员设备安全带来较大威胁。在区域地应力场回归分析的基础上,针对依据现有规范无法得到爆坑深度及对非圆形洞室判断结果存在一定误差的不足,引入了硬脆性岩体破坏预测准则(m-0准则)。在对该准则进行适应性判别后,采用所提方法和规范方法对该水电站引水隧洞剩余洞段岩爆可能性进行了综合判别。结果表明:采用m-0准则可对爆坑深度进行有效预测,剩余洞段岩爆主要以片帮和连续剥落的轻微岩爆为主,局部洞段具有发生中等岩爆和强烈岩爆的可能性。研究结果可用于该工程后续洞段开挖支护设计,另可为类似深埋硬岩工程岩爆可能性判别提供一定的借鉴及参考。

Some strain- type rock bursts,mainly stratified flaking and splitting destruction forms,occurred in the diversion tunnel construction of a hydropower station in Xinjiang during excavation,threatening the safety of equipment and personnel. Aiming at the defect that the present standards could not give depth of burst pit and could not provide accurate judgment for non-circle tunnels,we apply the brittle rock mass failure forecast criterion based on regional ground stress regression analysis. By the feasibility analysis of the presented method,the new method and standard method are used to determine the rock burst possibility of the remaining section of diversion tunnel. The results show that the brittle rock mass failure prediction criterion is suitable for forecasting the depth of burst pit,the remaining sections are flaking and splitting burst with the possibility of middle rock burst and even strong rock burst in local positions. The results can be used in the excavation and support design of the remaining section. This new method could provide a reference to judging the rock burst possibility of deep hard rock mass.