| The Longyanjing tunnel locate K1028+336.5～K1029+270 of G213.The wall work collapsed in many place and take place of serious great wall rock distortion because the most displacement of wall rock have achieve 100cm.It is not only baffle plan of construction very much and increase investment, but also threaten the personnel safety seriously. This dissertation takes great wall rock distortion as primary research object. After getting of geological environment of district and basal geological condition of research area. The text have chiefly developed following work by investigating in locale and analyzing in room:(1)This article achieve mechanism of great wall rock distortion of Longyanjing tunnel after analyzing style of great wall rock distortion, geological background of wall rock of Longyanjing tunnel,tunnel mechanism of great wall rock distortion: the distortion of wall rock belong to cataclasm looseness and gravitation collapse and effect together. The mechanism of great wall rock distortion belong to looseness expand.(2)This dissertation gained stress field, displacement field and plastic zones make use of three-dimensional numerical analysis after the tunnel have been excavated: There is low stress loop in the wall rock. The max principal stress under 3MPa and in 8-30m range of wall rock; The displacement field symmetry distributing approximately. The max displacement of facies of wall rock from 5cm to 86cm, correspond to constringency rate of displacement from 0.83% to 14.83%; There are many plastic zones in front of excavating in mountain. The degree of failure became more serious after excavating. The style of failure belongs to shear failure and tension failure together action. The depth about 10m in vault and motherboard of bound of shear-n failure, but the depth achieve 25m in left and right wall.(3)This dissertation present shoring methods when phase of investigation and design and phase of construction base on academic research of shoring methods when tunnel has been excavated.
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