隧道衬砌结构崩落特征及主要诱发因素

Characteristics and Main Inducements of Tunnel Lining Structure Collapse

为了科学地预测、控制、避免衬砌崩落灾害的发生,研究隧道衬砌结构崩落特征及主要诱发因素,找出衬砌崩落的潜在规律和关键性诱因,对35座衬砌崩落隧道案例信息进行归纳整理,统计分析了衬砌崩落时间、空间位置、地层岩性、二次衬砌材料的特征及规律。根据诱因数量,诱因类别以及每种诱因类别中各个诱因的占比情况,归纳总结了隧道衬砌崩落的主要诱发因素,分析了隧道衬砌崩落诱发因素的特征。结果表明:50%的衬砌崩落发生在隧道建成后10 a内,90%的衬砌崩落发生在隧道建成后40 a内;衬砌崩落主要发生在雨季和低温期,拱顶是预防衬砌崩落发生的主要位置;衬砌崩落多发生在围岩较为软岩的地层中,以及地下水丰富的硬岩地层;二次衬砌材料为素混凝土的隧道更容易发生衬砌崩落灾害;衬砌崩落诱发因素分为结构因素类和外部环境类2类,结构因素类诱因包括混凝土材料耐久性、质量缺陷和结构病害,外部环境类诱因包括围岩冻胀、围岩膨胀、高地应力、衬砌背后水压、滑塌、溶洞落石、地震和列车振动;衬砌崩落灾害主要是单一诱发因素引起,单一诱发因素中外部环境是主要诱因类别;结构因素中质量缺陷占比最大,其次是结构病害;外部环境因素中衬砌背后水压、围岩膨胀和高地应力是关键性因素。

In order to scientifically predict,control and avoid the occurrence of lining collapse disaster,the characteristics and main inducing factors of tunnel lining collapse are studied,and the potential rules and key inducing factors of lining collapse are found out.The case information of 35 tunnel with lining collapse is summarized,and the characteristics and rules of time,space,stratum lithology and secondary lining material are analyzed.According to the quantity of inducement,the category of inducement and the proportion of each inducement in each inducement category,the main inducement factors of tunnel lining collapse are summarized,and the characteristics of inducement factors of tunnel lining collapse are analyzed.The result shows that(1)50%of the lining collapses occur within 10 a after the tunnel is completed,and 90%of the lining collapses occur within 40 a after the tunnel is completed;(2)the collapse of lining occurs mainly in rainy season and low temperature period,and the vault is the main place to prevent the collapse of lining;(3)the lining collapse usually occurs in the stratum whose surrounding rock is soft rock and the stratum whose ground water is rich in hard rock;(4)the tunnel whose secondary lining material is plain concrete is more prone to lining collapse;(5)the inducing factors of lining collapse can be divided into 2 types of structural factors and external environmental factors,structural factors include durability of concrete materials,quality defects and structural diseases,and the external environmental factors include frost heaving of surrounding rock,swelling of surrounding rock,high in-situ stress,water pressure behind lining,collapse,karst cave falling,earthquake and train vibration;(6)the lining collapse disaster is mainly caused by a single inducing factor,and the external environment is the main inducing factor;(7)in the external environmental factors,the water pressure behind the lining,the expansion of surrounding rock and the high ground stress are the key factors.