Deformation mechanism of rock mass and prestressed anchor cable support technology of Haidong soft rock tunnel  

作　　者：LEI Xiaotian TAO Zhigang LIU Keyuan YANG Hong CAI Mingjiu FAN Xiaowei 

机构地区：[1]State Key Laboratory for Tunnel Engineering,Beijing 100083,China [2]School of Mechanics and Civil Engineering,China University of Mining&Technology,Beijing 100083,China [3]China Railway 20th Bureau Group Co.,Ltd.,Xi’an 710016,China [4]China Railway 5th Bureau Fifth Company,Chenzhou 423000,China [5]School of Energy and Environment,Zhongyuan University of Technology,Zhengzhou 450007,China

出　　处：《Journal of Mountain Science》2024年第12期4299-4322,共24页山地科学学报（英文）

基　　金：supported by the China Yunnan Province Major Science and Technology Special Plan Foundation Project (Grant No. 202002AF080003);the China Railway No.5 Engineering Group Co., Ltd.

摘　　要：The Haidong Tunnel is one of the four soft rock tunnels of the Central Yunnan Water Diversion Project(CYWDP),where large deformation hazards of soft rock occur frequently,which seriously affect construction safety.The effect of highly prestressed anchor cable support was studied based on the active support test in the No.3 branch tunnel of Haidong Tunnel.Firstly,the geological conditions and failure causes were analyzed on the basis of the results of geological survey,in-situ test,and rock laboratory test.Then,the Mohr circle form of the highly prestressed anchor cable active support theory for the support of bedded rock mass was given in combination with the excavation compensation method.It is considered that the prestress active compensation value required for the bedded rock mass is larger than that for the homogeneous rock mass.The deformations of rock mass under both passive and active supports were analyzed by numerical simulations.Furthermore,the'pressure bubble'mechanical model for anchor cable support of bedded rock mass in Haidong Tunnel is given.Field monitoring results show that the highly prestressed anchor cable support can control rock mass deformation well,with a maximum deformation of about 200 mm.The prestressed anchor cable is effective in the bedded stratum,which makes the stress of rock mass uniform and reduces the risk of failure of steel arches due to local bias.Meanwhile,the expansion of plastic zone was efficiently controlled,which is of positive significance for the overall stability of rock mass.

关 键 词：Central Yunnan Water Diversion Project Large deformation of soft rock Prestressed anchor cable Active support 'Pressure bubble'mechanical model 

分 类 号：TV554[水利工程—水利水电工程]