杜公岭隧道工程地质特征及工程危害性分析

Analysis on Geological Characteristics and Its Engineering Harmfulness of Dugongling Tunnel

为查清杜公岭隧道工程地质条件与隧道病害间的关系,通过对杜公岭隧道工程地质条件的论述,分析了隧道工程地质特征,探讨了各类地质因素对隧道工程的潜在危害与风险。结合杜公岭隧道工程建成运营后出现的隧道病害与检测情况,系统地分析了多种工程地质因素对隧道工程产生危害的作用机理。研究表明:杜公岭隧道工程地质危害性是由地层岩性、地下水、岩溶、地质构造等多种地质因素共同作用的结果。在这些影响因素中,地下水显化并加剧了隧址区各种工程地质因素,促使隧道围岩产生软化膨胀、隧道衬砌支护结构附加荷载增加、隧道衬砌混凝土结构遭受硫酸盐侵蚀等;岩溶为地下水的流通与汇集提供的途径,使得大气降水对其快速补给,并在局部区域汇集;围岩中的石膏岩在地下水的作用下产生膨胀,并为地下水的腐蚀提供了硫酸根离子供给;各类危害行为相继出现、互相交织,对隧道衬砌结构从不同的方面造成了损害,使其隧道衬砌呈现出不同的病害表现形式。因此,隧道工程的安全性与稳定性常受控于隧址区工程地质条件,而由于现有技术与人类认知的局限,无法实现对隧址区工程地质信息的透明化获取与工程危害性的精准预判,使得隧道工程建设常面临较高风险。

In order to find out the relationship between engineering geological condition and disease of Dugongling tunnel, through discuss the engineering geological conditions of Dugongling tunnel, the engineering geological characteristics of the tunnel area are analyzed and the potential hazards and risks of various geological factors to the tunnel are discussed. According to the tunnel disease and the testing situation after the tunnel completion and operation, the destructive mechanism of several geological factors to the tunnel engineering are systematically analyzed. The research result shows that (1) The geological harmfulness of Dugongling tunnel project is a result of multiple geological factors such as stratigraphic lithology, groundwater, karst and geological structure. Among them, the groundwater manifests and aggravates all kinds of geological factors in the tunnel area, which makes surrounding rock softening and expansion, additional load of the tunnel lining of support structure increasing, and the concrete structure of lining suffering from sulfate corrosion, etc.(2) Karst provides the way for the infiltration and collection of groundwater, which makes atmospheric precipitation rapidly supply and converge in local areas.(3) The gypsum rock in surrounding rock expands under the action of groundwater, and provides sulfate ion supply for groundwater corrosion.(4)Various hazards occur one after another and interweave with each other, causing damage to the tunnel lining structure from different aspects and presenting different manifestations of disease in the tunnel lining structure. So, the safety and stability of tunnel engineering are controlled by its engineering geological conditions, while the tunnel construction has become a high-risk engineering because that it could not to reveal more about the engineering geological information and accurately evaluate the engineering harmfulness of the tunnel areas as the limitation of the current technology and the human cognition.