冰碛层围岩稳定性及亚分级研究  

Study on the Stability and Sub-Classification of Moraine Surrounding Rock

作　　者：王明年[1,2] 王岩[1,2] 胡云鹏 吴圣智 刘大刚 WANG Mingnian;WANG Yan;HU Yunpeng;WU Shengzhi;LIU Dagang(Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu Sichuan 610031,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu Sichuan 610031,China)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,四川成都610031 [2]西南交通大学土木工程学院,四川成都610031

出　　处：《中国铁道科学》2020年第4期64-73,共10页China Railway Science

基　　金：四川省科技计划重点研发项目(2019YFG0001);中国铁路总公司科技研究开发计划课题(2017G006-B)。

摘　　要：依托拉林铁路藏噶隧道,采用现场取样、室内土工试验和数值模拟的方法,选取密实程度、含石量和含水率3个主要影响因素,对冰碛层围岩稳定性及亚分级展开研究。结果表明:冰碛层围岩的抗剪强度随密实程度和含石量的增大逐渐增大,随含水率的增大逐渐减小;冰碛层围岩塌方过程分为3类,分别为"局部塌方、小塌方、中~大塌方""局部失稳、中~大塌方"和"大塌方";冰碛层围岩亚分级可分为Ⅳ2,Ⅴ1和Ⅴ2共3个亚级,分级指标为密实程度、含石量和含水率。依据藏噶隧道冰碛层段"三台阶"施工方法,推荐Ⅳ2亚级围岩采用型钢钢架和管棚支护;Ⅴ1亚级围岩采用"管棚+小导管"超前加固、型钢钢架和管棚支护;Ⅴ2亚级围岩采用"帷幕注浆、管棚+小导管"超前加固、型钢钢架和管棚支护。现场采用对应的加固措施后,最大沉降小于100 mm,满足隧道施工要求。Based on the method of field sampling,indoor geotechnical test and numerical simulation for Zangga tunnel of Lhasa-Linzhi Railway,the stability and sub-classification of the moraine surrounding rock were studied by selecting three factors:compactness,stone content and water content.Results show that the shear strength of the moraine surrounding rock increases gradually with the increase of compactness and stone content,and decreases gradually with the increase of the water content.The collapse process of the moraine surrounding rock is divided into three modes,which are"local landslide,small landslide,medium to large landslide","local instability,medium to large landslide"and"large landslide".The sub-classification of the moraine surrounding rock can be divided into three sub-classes:Ⅳ2,Ⅴ1 andⅤ2.The classification indicators are compactness,stone content and water content.Based on the construction method of"three-step"in the moraine surrounding rock section of Zangga tunnel,it is recommended that the subclassⅣ2 surrounding rock be supported by profile steel frame and pipe shed.The subclassⅤ1 surrounding rock can be reinforced with"pipe shed+small duct"in advance,and be supported by profile steel frame and pipe shed.The subclassⅤ2 surrounding rock can be reinforced in advance with"curtain grouting,pipe shed+small duct",and be supported by profile steel frame and pipe shed.After the corresponding reinforcement measures are adopted on site,the maximum settlement is less than 100 mm,which meets the requirements of tunnel construction.

关 键 词：隧道 冰碛层围岩 围岩稳定性 围岩亚分级 围岩支护 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]