Squeezing deformation control during bench excavation for the Jinping deep soft-rock tunnel

doi:10.1016/j.engfailanal.2020.104761

	Squeezing deformation control during bench excavation for the Jinping deep soft-rock tunnel
	Zhang, Chuanqing 1,4; Cui, Guojian 1,4; Zhang, Yang 3; Zhou, Hui 1,4; Liu, Ning 3; Huang, Shuling 2
刊名	ENGINEERING FAILURE ANALYSIS
	2020-10-01
卷号	116 页码:19
关键词	Deep tunnel Soft rocks Squeezing deformation Parameter inversion Support and reinforcement Optimisation design
ISSN号	1350-6307
DOI	10.1016/j.engfailanal.2020.104761
英文摘要	Jinping II hydropower station in Sichuan Province, China, is one of the largest tunnel groups in the world. The tunnel was excavated using bench excavation with a top heading and a bench. Severe squeezing problems were reported immediately after the excavation of the top heading when crossing the chlorite schist stratum at Ch.1+537 m. Squeezing deformation could last for a long period during tunnelling, similar to the problem of rockburst reported in the marble stratum distributed in the middle and east of the headrace tunnels. One year after the top heading excavation, the profile of the top heading still violated the profile tolerance and had to be reshaped due to the large convergence. A new support scheme was proposed to ensure the stability of the surrounding rock mass and control the excessive squeezing deformation during the bench excavation. For this, laboratory triaxial tests were first conducted under saturated and dry conditions to acquire the mechanical properties of chlorite schist. Then, the mechanical parameters of intact and damaged surrounding rock mass were determined using Hoek empirical estimation and a displacement inversion method, respectively. Next, initial support design was re-reviewed and evaluated based on the field displacement measurements, and the potential for squeezing in the overstressed rock mass was estimated. Thereafter, 10 supplementary support schemes were proposed using the numerical method in combination with laboratory data and field observations. Finally, the optimised support scheme was selected based on the results of comparative analysis. Field application of the suggested scheme showed that the convergence was controlled to within an acceptable level throughout the entire period of excavation of the lower bench. The experiences of controlling excessive squeezing deformation and optimisation of the support scheme for rock strata in a high geo-stress environment provide a reference for similar projects in the presence of soft rocks.
资助项目	Key projects of the Yalong River Joint Fund of the National Natural Science Foundation of China[U1865203] ; National Key Research and Development Program of China[2018YFC0809601] ; Youth Innovation Promotion Association CAS ; Yalong River Hydropower Development Company LTD
WOS研究方向	Engineering ; Materials Science
语种	英语
出版者	PERGAMON-ELSEVIER SCIENCE LTD
WOS记录号	WOS:000567790700003
内容类型	期刊论文
源URL	[http://119.78.100.198/handle/2S6PX9GI/24887]
专题	中科院武汉岩土力学所
通讯作者	Cui, Guojian
作者单位	1.Chinese Acad Sci, Inst Rock & Soil Mech, State Key Lab Geomecha & Geotech Engn, Wuhan, Hubei, Peoples R China 2.Changjiang River Sci Res Inst, Minist Water Resources, Key Lab Geotech Mech & Engn, Wuhan, Hubei, Peoples R China 3.PowerChina Huadong Engn Corp Ltd, Hangzhou, Zhejiang, Peoples R China 4.Univ Chinese Acad Sci, Beijing, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Chuanqing,Cui, Guojian,Zhang, Yang,et al. Squeezing deformation control during bench excavation for the Jinping deep soft-rock tunnel[J]. ENGINEERING FAILURE ANALYSIS,2020,116:19.
APA	Zhang, Chuanqing,Cui, Guojian,Zhang, Yang,Zhou, Hui,Liu, Ning,&Huang, Shuling.(2020).Squeezing deformation control during bench excavation for the Jinping deep soft-rock tunnel.ENGINEERING FAILURE ANALYSIS,116,19.
MLA	Zhang, Chuanqing,et al."Squeezing deformation control during bench excavation for the Jinping deep soft-rock tunnel".ENGINEERING FAILURE ANALYSIS 116(2020):19.