摘要
研究目的:与典型的岩爆易发区为强烈挤压构造区不同,现今伸展构造为主的秦岭东段也具有高地应力、强岩爆特征。为保障铁路隧道等深地工程的建设和选线,本文对其地应力场特征、构造成因以及对岩爆的总体控制作用进行初步研究。研究结论:(1)秦岭东段实测最大水平主应力S_(H)的挤压方向不受现今区域构造控制,而表现出与伸展构造方向一致的NW-SE,S_(H)平均变化梯度高达2.94 MPa/100 m,与青藏高原相当,综合来看,该区以燕山期挤压作用形成的构造地应力为主,属于残余应力,该特征指示岩体应变能可保留达上亿年,且大型岩体内部的应变能不易被伸展构造所改变;(2)区域上,秦岭东段S_(H)始终为三向主应力中的最大值,是岩爆风险的主控因子,在铁路选线阶段,秦岭东段需重点考虑花岗岩和闪长岩等硬质岩的岩爆风险,700 m以上易发生中等岩爆,1400 m以上易发生强烈岩爆,建议尽量避免1400 m以上埋深隧道;(3)本研究成果可推广应用于秦岭及类似山区铁路地质选线及隧道岩爆风险防控。
Research purposes:Different from the typical rock burst prone area which is a strong compressive tectonic area,the eastern Qinling,which is dominated by the extensional structure in present,also has the characteristics of high in-situ stress and strong rock burst risk.In order to guarantee the construction and route selection of deep ground projects such as railway tunnels,this paper makes a preliminary study on the characteristics of the in-situ stress field,the tectonic causes and the overall control of rock burst.Research conclusions:(1)The measured extrusion direction of the maximum horizontal principal stress S_(H)in the eastern Qinling is consistent with the direction of the current extensional structure in the area,both of which are NW-SE.This indicates that the in-situ stress is not controlled by current regional tectonics.The average variation gradient of S_(H)is as high as 2.94 MPa/100 m,which is equivalent to that of the Tibet Plateau.Therefore,the area is dominated by the tectonic stress formed by squeezing during Yanshanian,which belongs to the residual stress.This feature indicates that the strain energy of intact rock mass can be retained for hundreds of millions of years,and the strain energy in large rock mass is not easily changed by extensional structure.(2)Regionally,S_(H)in the eastern Qinling is always the maximum value of the three-way principal stress,which is the main control factor of rock burst risk.In the stage of railway route selection,the eastern Qinling needs to focus on the rock burst risk of hard rocks such as granite and diorite.Medium rock burst is easy to occur above 700 m,and strong rock burst is easy to occur above 1400 m.It is recommended to avoid tunnels buried more than 1400 m.(3)This research achievement can be popularized and applied to the geological route selection of Qinling and similar mountain railways and the prevention and control of tunnel rock burst risk.
作者
陈兴强
刘瑾
孟祥连
张文忠
黄勇
王华江
周福军
李玉波
李立民
王凯
邱士利
CHEN Xingqiang;LIU Jin;MENG Xianglian;ZHANG Wenzhong;HUANG Yong;WANG Huajiang;ZHOU Fujun;LI Yubo;LI Limin;WANG Kai;QIU Shili(China Railway First Survey and Design Institute Group Co.Ltd,Xi'an,Shaanxi 710043,China;Xi'an Technological University,Xi'an,Shaanxi 710021,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China)
出处
《铁道工程学报》
EI
CSCD
北大核心
2023年第2期1-5,77,共6页
Journal of Railway Engineering Society
基金
国家自然科学基金(42102266,42202240)
陕西省科技厅科技计划项目(2023-YBSF-238,2021JLM-51)
关键词
秦岭
铁路隧道
新构造
地应力
青藏高原
Qinling
railway tunnel
neotectonics
in-situ stress
Tibet Plateau
