强震区成兰铁路某隧道大变形地质成因分析

发布时间：2018-09-06 08:11

【摘要】：研究目的:在建成兰铁路以复杂活跃的地质构造条件、极为显著的地震效应、高水平构造应力场特征及软弱破碎的地层岩性等复杂的地质条件为其地质背景,强震区软弱破碎围岩隧道大变形现象较为普遍。本文在现场调绘、试验资料、变形监控量测资料等分析的基础上,从工程地质环境、地层岩性、地质构造、地下水、地震及应力场等方面,以工程地质的角度,对强震区软弱破碎围岩隧道大变形的成因机制进行分析研究。研究结论:(1)变形段处于汶川"5·12"强震区龙门山前山断裂之彭县-灌县断裂带影响区内,围岩震裂破碎效应极为显著;(2)大变形主要表现为初支拱顶下沉、边墙侵限开裂、剥落、初支钢架扭曲等破坏特征;(3)变形工区段受龙门山断裂构造及汶川"5·12"强震震裂影响严重,岩体中节理裂隙发育,变形破坏地质成因机制可总结为:软弱破碎的围岩条件为大变形产生的物质基础,复杂的高应力场环境为大变形产生的力学条件,结构面引起的顺层偏压现象和地下水的软化特性等进一步加剧了大变形;(4)变形工区段应加强初支的监控量测管理,及时进行量测数据的反馈与分析,科学、准确地评价大变形的成因机制;(5)本文的分析方法及结论对强震区类似工程地质条件下软弱破碎围岩隧道大变形的设计及施工具有借鉴意义。
[Abstract]:The purpose of this study is to study the complex geological conditions of the Lanzhou Railway, such as complex and active geological structural conditions, extremely significant seismic effects, characteristics of high level tectonic stress field and weak and broken strata and lithology, etc. The large deformation phenomenon of weak and broken surrounding rock tunnel in strong earthquake area is common. Based on the analysis of field mapping, test data, deformation monitoring and measurement data, this paper discusses engineering geology from engineering geological environment, stratigraphic lithology, geological structure, groundwater, earthquake and stress field, etc. The mechanism of large deformation of soft and broken surrounding rock tunnel in strong earthquake area is analyzed and studied. The conclusions are as follows: (1) the deformation section is located in the Pengxian-Guanxian fault zone of Qianshan fault of Longmenshan in Wenchuan "512" strong earthquake area, and the fracture effect of surrounding rock is very remarkable. (3) the deformation zone is seriously affected by the Longmenshan fault structure and the Wenchuan "512" strong earthquake crack, and the joints and fissures are developed in the rock mass. The geological mechanism of deformation and failure can be summarized as follows: the weak and broken surrounding rock condition is the material foundation of large deformation, and the complex high stress field environment is the mechanical condition of large deformation. The phenomenon of bedding bias caused by the structure plane and the softening characteristics of groundwater further aggravate the large deformation. (4) the monitoring and measurement management of the initial support should be strengthened in the deformation working area, and the feedback and analysis of the measured data should be carried out in time. (5) the analytical methods and conclusions of this paper can be used for reference in the design and construction of large deformation of soft and broken surrounding rock tunnel under similar engineering geological conditions in strong earthquake area.
【作者单位】：中铁二院工程集团有限责任公司地质创新工作室;中铁二院工程集团有限责任公司;
【基金】：铁道部科技研究开发计划(Z2012-061) 中国铁路总公司科技研究开发计划项目(2013G014-B)
【分类号】：U452.11

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