摘要
为探究走滑断层错动下隧道结构的变形特征及受力机制,明晰走滑断层的性质及受力模式,采用现场调查、地质力学配套分析及数值模拟等方法,分析地震影响下大梁隧道产生的地表裂缝分布规律。研究结果表明:(1)确定了断层走向NW60°,与区域上冷龙岭断裂位置一致,属全新世活断层。隧道中断层面产状为195°∠79°,破碎带宽约100 m,地表裂缝错移3 m;距大梁隧道出口南侧约700 m处水平错移2.8~3.0 m,逆冲错动位移0.91m,具有逆冲走滑运动特征。(2)地震破坏力学模式为NE-SW60°主应力单向挤压、纯剪共同作用;结合主裂缝带边界逆冲地表变形特征,地表裂缝具有逆冲断裂造山式花状形态;(3)通过地质力学配套分析,在断层受单向力和力偶作用下,地表产生裂缝分布规律与现场调查裂缝分布规律一致。(4)大梁隧道变形破坏模式,在门源地震之前主要受区域的主应力的作用,以SW60°挤压作用为主;在门源地震以后,主要以剪切挤压为主,隧道结构受主应力NESW60°挤压和NW60°冷龙岭断裂的走滑剪切作用。本次调查分析结果为穿越活动断层高铁隧道的工程设计提供参考。
In order to explore the deformation characteristics and stress mechanism of tunnel structure under the dislocation of strike-slip fault,and clarify the mechanical status of strike-slip fault,the distribution rules of surface cracks caused by earthquake in Daliang tunnel are analysed by means of field investigation,geomechanical analysis and numerical simulation.The results show that:(1)the strike of the fault is NW60°,which is consistent with the location of the Lenglongling fault in the region and belongs to the Holocene Active fault.The occurrence of the interrupted layer of the tunnel is 195°∠79°,the width of weak layer is about 100 m,and the size of surface crack dislocation is 3 m.About 700 m to the south of the exit of Daliang tunnel,the horizontal displacement is 2.8 m,and the thrust displacement is 0.91 m,which has the characteristics of thrust strike-slip movement.(2)The mechanical mode of seismic failure is the combined action of NE-SW60°principal stress,unidirectional compression and pure shear.Considering the characteristics of thrust surface deformation at the boundary of the main fracture zone,the surface fractures have a thrust fault orogenic flower shape.(3)Through the analysis of geomechanics,under unidirectional force and moment on the fault,the distribution law of cracks on the surface is consistent with that of field investigation.(4)Before the Menyuan earthquake,the deformation and failure mode of Daliang tunnel was mainly affected by the regional principal compression stress on the direction of on SW60°.After the Menyuan earthquake,it was mainly affected by shearing and compression,and the tunnel structure was subjected to the principal compression stress on the direction of NE-SW60°and the strike-slip shear on the direction of NW60°accorded with Lenglongling fault.The investigation and analysis results provide a reference for the engineering design of high-speed railway tunnels crossing active faults.
作者
张玉芳
袁坤
周文皎
范家玮
ZHANG Yufang;YUAN Kun;ZHOU Wenjiao;FAN Jiawei(Railway Engineering Research Institute,China Academy of Railway Sciences,Beijing 100081,China;China Academy of Railway Sciences,Beijing 100081,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2023年第5期1055-1069,共15页
Chinese Journal of Rock Mechanics and Engineering
基金
中国国家铁路集团有限公司科技研发计划资助项目(N2021G008)。
关键词
隧道工程
门源地震
高速铁路
逆冲走滑断层
地质力学配套
tunnelling engineering
Menyuan earthquake
high-speed railway
thrust strike-slip fault
geomechanical matching
