为保证深埋隧道安全通过侧部高压富水溶洞区段,在隧道突水发生机制分析与隔水岩体最小安全厚度划分的基础上,结合突变理论、鲁宾涅特方程及相关工程经验对隧道边墙岩体安全厚度进行研究,导出最小安全厚度计算公式,建立突水判据,分析相关影响因素对隧道边墙隔水岩体最小安全厚度的影响规律。结果表明:隔水岩体最小安全厚度H_min与围岩力学参数弹性模量E、内摩擦角φ呈正相关,与溶洞水压力q_w、岩梁跨度L及隧道埋深h呈负相关;各因素对H_min影响程度由大到小依次为h、φ、E、L与q_w,其中h与φ影响程度相近,E在超过3 GPa的情况下H_min变化趋于平缓,E的影响程度与L相近;结合有限元模拟结果和工程实例分析,验证了H_min理论计算公式及突水判据的准确性与可行性,对相关工程建设具有指导意义。

川东隔挡式褶皱带一直是四川、重庆东西向交通通道的天然屏障,隧道可快速穿越褶皱山区,但其在建设时却常常遭遇岩溶涌突水等地质灾害,威胁着施工人员安全与生态地质环境。通过分析川东明月峡背斜区各类排泄基准面控制的地下水循环模式,研究了明月山及所在的川东地区地下岩溶发育规律及岩溶发育深度。结果表明:川东及明月峡背斜区主要可分为贯穿河谷型、横向深切沟谷型、横向浅切沟谷型3类排泄基准面控制的地下水循环模式;在贯穿河谷控制的地区,岩溶向深发育;横向深切沟谷控制的地带,岩溶也具有一定向深发育的能力,岩溶发育深度一般在沟谷之下200~500 m;横向浅切沟谷密集发育的地带地下岩溶发育深度大致在200 m以内。研究结果对于预测与规避川东地区隧道建设时面临的岩溶涌突水灾害及减小其对地质环境的影响有参考价值。

The belt of folded strata in east Sichuan has always been a natural barrier for the transportation eastward of Sichuan and Chongqing. Tunnels could pass through the folded mountainous area quickly; but tunnel construction often encounters geological disasters such as karst gushing and water inrush, which threatens the safety of construction workers and ecological geological environment. By analyzing the groundwater circulation patterns controlled by various discharge datum in the anticline area of Mingyue Gorge in east Sichuan, we studied the development rules and depth of underground karst in Mingyue mountain and east Sichuan, and obtained the following conclusions: in east Sichuan and the Mingyue Gorge anticline zone, the groundwater circulation mode can be divided into three patterns according to the discharge datum: penetrative valley, transverse deep valleys, and transverse shallow valleys. In penetrative valley controlled region, karst develops to the deep; in transverse deep valley controlled zone, karst also develops to the deep in the range 200-500 meters below the valley; in transverse shallow valleys, karst develops roughly within 200 m range. The research findings are of referential value to predicting and avoiding karst gushing as well as reducing impact on geological environment.

采用UDEC离散单元法中关于裂隙岩体开挖模拟及水力全耦合分析模型，分析裂隙岩体洞室开挖后，围岩应力与水力耦合作用导致的裂隙隙宽变化及渗流变化的过程。结果表明：洞室开挖完成后，在围岩渗流与应力耦合作用下，围岩中裂隙隙宽、裂隙中水压及其渗透流量的变化是一个动态过程，且相互作用与相互依赖；裂隙的闭合使得结构面水力梯度变大，作用在裂缝上的渗透压力增大，促进导水裂缝扩展，裂隙连通性增加；裂缝张开度增大，渗透能力增强，渗流量增大，其渗流压力相应降低；由于围岩中裂隙隙宽、压力和渗流量的动态依赖性，在一定条件下，裂隙隙宽的改变可导致局部水力通道的形成，高压水头从局部涌出，从而促进突水灾害的形成。研究成果初步表明了所采用方法的有效性，并为研究裂隙岩体中开挖洞室引起的突水问题提供了潜在的研究方向。

The excavation simulation and fully-coupled model of the fractured rock in the discrete element method are used to analyze the changes in fracture aperture and the process of the flow change after excavation. The results show that the change of the fracture aperture, water pressure and fracture permeability of the fractured rock mass in the coupling conditions of the seepage and stress is a dynamic process, and also shows its interaction and interdependence. Owing to the closure of the fracture, the hydraulic gradient and the permeability pressure of the fracture turn large, and also promote the expansion of water cracks, and fissures connectivity increasing. The increase of the crack opening width will result in the increase of the infiltration capacity and seepage flow, and the reduction of seepage pressure. Because of the dynamic dependence of the fracture aperture, pressure and seepage, under certain conditions, changes in fracture aperture can lead to the formation of local water-passage, and the local emission of high pressure water, and thus promotes the formation of the sudden outgush disasters. Preliminary research shows the effectiveness of the method employed, and provides a potential research direction to study the sudden blowing in the excavation of fractured rock masses.

The discrete element method can be used to simulate the excavation of the fractured rock and conduct the fully-coupled analysis of hydraulics. So UDEC (universal distinct element code) can be used to simulate the changes of flow rate and the corresponding water pressure under the coupling conditions of the seepage and stress after the excavation of the fractured rock, and forecast the possible sudden blow disasters. The results show that the changes of the fracture aperture, water pressure and fracture permeability discharge of the fractured rock mass in the coupling conditions of the seepage and stress are interactive and interdependent. Because of the shortening of the fracture width, the hydraulic gradient and the permeability pressure of the fracture become large. It also promotes the expansion of cracks and fissure connectivity increases. The increase of the crack width will result in the increase of the infiltration capacity and seepage discharge and reduction of seepage pressure. Under certain conditions, changes in fracture aperture can lead to the formation of local water  access, the emission of high pressure head from the local place, and thus promotes the formation of the sudden blow disasters. The sudden blow easily occurs after the excavation of the diversion tunnel situated at the deep fractured rock where the ground stress and water pressure are very high in some hydropower station in the southwest of China. The simulation is done in this article, and some possible positions where the sudden blow occur are revealed.

为了掌握玄武岩地层向斜构造不良地质体构造特征与突泥突水机制,以滇中引水工程狮子山隧洞穿越乌龙坝向斜构核部附近突水突泥灾害为例,研究了该段突水突泥灾害演化与致灾地质构造、致灾介质基本特征与致灾动力及诱发机制。结果表明:①突涌原因为构造向斜上盘节理裂隙密集带储水构造使下位凝灰岩裂缝扩展发育崩解软化、泥化,连接上部储水构造体,导致致灾介质体突涌;②突水突泥致灾介质类似稀性泥石流,瞬时爆发涌出,携带巨大能量;③隧洞卸荷坍塌、地下水作用及应力释放等共同作用导致了灾害形成。研究成果对隧道穿越褶皱构造防治突泥突水灾害具有一定指导意义。

The aim of this study is to understand the structural characteristics of unfavorable geological bodies and the mechanism of mud and water inrush in the syncline structure of basalt strata. We investigated into the evolution of water and mud inrush, the disaster-causing geological structure, the basic characteristics of disaster-causing medium, the disaster-causing power and the disaster-inducing mechanism at the core of Wulongba syncline structure in Shizishan tunnel of Central Yunnan Water Diversion Project as a case study. Results demonstrated that the water inrush is resulted from the disintegration, softening and argillization of lower tuff cracks caused by the water storage structure in joint fissure dense zone of the upper syncline structure; 2) the diluted debris flow like water inrush medium carries huge energy while bursting instantaneously; 3) the water and mud inrush disaster is caused jointly by tunnel unloading collapse, groundwater action and stress release. The research finding is of guiding significance for mud and water inrush prevention for tunnels crossing fold structure.<br/><br/>

为了探索岩溶隧道在施工过程中经常出现由于裂缝引发突水的灾害机理，利用水压致裂原理重点分析研究拉剪破坏突水和压剪破坏突水的力学过程和裂缝扩展过程中缝内水压分布特征和梯度。研究表明突水临界水压受裂缝的走向、所处位置等因素的影响;含水裂缝发生拉剪破坏所需的临界水压力大于其发生压剪破坏所需的临界水压力;在水力劈裂作用下裂缝的生长呈现间断性特征。研究成果对隧道施工过程中突水灾害的防治具有重要的意义。