Analysis of Tunnel Lining Deformation in Complex Geology and Engineering Control Technology
XIA Run-he1,CUI Xiao-peng1,ZHOU QuanZ
(1 .CCCC Second Highway Engineering Co. Ltd,Xi'an,Shaanxi710065,China;2. China Railway First Survey and Design Institute Group Co. Ltd,Xi'an,Shaanxi 710043,China
Abstract:Research purposes:The newly-built Lanzhou-Chongqing Railway is the key project of China's”Mid- Term and Long-term Railway Network Development Program",the Liangshui tunnel of Lanzhou-Chongqing Railway in the construction process encountered in high geo stress,the maximum level principal stress value of surrounding rock is 6. 5-11.3 MPa,tunnel surrounding rock has the characteristics of large deformation and fast speed. In the pre construction tunnel excavation,these conditions occur frequently such as large deformation of tunnel primary support structure,part of the steel arch distortion and fracture,support structure instability,the initial supporting structure to penetrate the lining clearance,removing and replacing arch. After the tunnel links,lining concrete cracking,spelling, the cross section deformation and clearance-intrusion phenomena appear in local section of tunnel lining,which brings great security risks to tunnel construction and operation. Aiming at the problems of tunnel lining,after full analysis of the causes of deformation and cracking,this paper studies the process parameters of the test section for lining demolition for arch,analyzes stress and deformation rules of tunnel support and lining structure by strict monitoring,and puts forward reasonable engineering treatment measures.
Research conclusions:(1)The regional geological structure of Liangshui tunnel is very complicated,for the weak thin slate,phyllite or carbonaceous phyllite in high stress,large deformation of surrounding rock appears and causes long passages of primary support deformation and lining.(2)Based on the construction experience,combined with the amount of field test section of surrounding rock large data analysis,double the initial support and double lining engineering measures are taken,the initial supporting arch strength is further optimized,which can effectively control the large deformation of tunnel lining.(3)According to high security risk for the demolition of arch construction,the measures with short,quick support, demolition of temporary arch,setting locking anchor pipe and following the rapid tunnel two lining,can further reduce and control the security risk. (4)The treatment measures proposed by this paper are based on the large section double line tunnel of railway through the geological conditions of soft rock deformation and rare condition of failure and deformation of initial support and lining,which has a certain guiding value for the similar tunnel construction.
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