钻爆施工条件下岩溶隧道掌子面突水机制及最小安全厚度研究  

Water inrush mechanism and minimum safe thickness of rock wall of karst tunnel face under blast excavation

作　　者：李术才[1] 袁永才[1] 李利平[1] 叶志华 张乾青[1] 雷霆[1] 

机构地区：[1]山东大学岩土与结构工程研究中心,山东济南250061 [2]湖北省保宜高速公路建设指挥部,湖北宜昌444200

出　　处：《岩土工程学报》2015年第2期313-320,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家重点基础研究发展计划(973)项目(2013CB036000);国家自然科学基金重点项目(51139004);国家自然科学基金面上基金项目(51479106);湖北省交通运输厅科研项目(BYXYKY2012-003)

摘　　要：岩体裂纹的水力劈裂破坏是岩溶隧道突水灾害发生的主要影响因素之一。从断裂力学角度分析了在钻爆施工条件下爆炸应力波对含水裂纹岩体扩展的影响,结果表明爆炸应力波通过增大孔隙水压力影响裂纹扩展模式;通过建立的岩体含水裂纹扩展计算模型,推导了在爆炸应力波作用下裂纹发生压剪扩展破坏时的临界水压力Pc,并被实例所验证。基于理论分析、数值试验及工程实例,得出了岩体含水裂纹压剪扩展破坏突水存在滞后效应,施工人员可利用这一特点,在发生突水灾害前,及时停工并迅速撤离,保证人员与机械设备的安全。最后,通过对岩溶隧道掌子面与高压含水体之间裂隙岩体的防突最小安全厚度的研究,提出"两带"理论,推导了合理反映爆破开挖扰动与水压作用下裂纹岩体最小安全厚度计算公式,并为工程实例所验证,其结果可为高风险岩溶地区隧道突水预测及防治提供理论依据。The hydraulic fracturing of rock mass is one of the main factors for water inrush in karst tunnels. From the perspective of fracture mechanics, the impact of explosive stress wave on extension of water-carrying fracture is studied under drilling and blast construction. The results show that the expansion pattern of fracture is influenced by the pore water pressure produced by the explosive stress wave. By establishing the computational model for fractured rock mass, the critical water pressure(Pc) under the explosive stress wave is deduced, and it is verified by cases. Based on the theoretical analysis, numerical experiments and engineering cases, the hysteresis effect of water inrush caused by extended compression-shear failure of rock mass is obtained. According to the hysteresis effect, constructors can terminate construction and leave immediately before the occurrence of water inrush so as to ensure the safety of personnel and mechanical equipments. By analyzing the minimum safe thickness between the fractured rocks of karst tunnel face and high-pressure aquifer, 'Two-band theory' is put forward. Furthermore, the formula for the minimum safe thickness is deduced, which can reflect the excavation and water pressure reasonably and is verified by engineering cases. It may provide a reference for the effective measures for water inrush in high-risk karst areas.

关 键 词：钻爆施工 裂纹扩展 突水滞后 最小安全厚度 应力波 

分 类 号：U455.41[建筑科学—桥梁与隧道工程] U453.6[交通运输工程—道路与铁道工程]