Investigation of the failure mechanism and theoretical model of bolt-reinforced shallow tunnel faces with different bolt lengths
作者机构：School of Civil EngineeringSouthwest Jiaotong UniversityChengdu 610036SichuanChina Key Laboratory of Traffic Tunnel EngineeringMinistry of EducationSouthwest Jiaotong UniversityChengdu 610036SichuanChina School of Transportation and LogisticsSouthwest Jiaotong UniversityChengdu 610036SichuanChina
出 版 物：《Underground Space》 (地下空间（英文）)
年 卷 期：2024年第16卷第3期
页 面：126-142页
核心收录：
学科分类：081901[工学-采矿工程] 0819[工学-矿业工程] 08[工学]
基 金：the National Natural Science Foundation of China(Grant Nos.52208404 and 52378411)
主 题：Failure mechanism Face bolting Tunnel face stability Bolt length Reinforcing mechanism
摘 要：Using fiberglass bolts to reinforce a tunnel face is a practical auxiliary technology for ensuring tunnel face stability in soft *** reinforcing effect and the economics of this technology are significantly affected by bolt ***,to date,the failure mechanism of bolt-reinforced tunnel faces with different bolt lengths has rarely been *** reveal the failure mechanism of bolt-reinforced shallow tunnel faces,in this study,the stability of bolt-reinforced tunnel faces with different bolt lengths was investigated by using laboratory tests and numerical simulations,and a simplified theoretical model for practical engineering was *** face support pressure and failure pattern for different bolt lengths during the face collapse process were obtained,and the influence of bolt length on face stability was clearly *** specifically,the results show that face stability increases with increasing bolt length,and the reinforcing effect of face bolts is governed by the shear failure at the soil-grout interface first in the stable zone of the tunnel face and then in the failure *** the bolt length in the stable zone is larger than that in the failure zone,face stability will not be improved with increasing bolt length;thus,this bolt length is referred to as the optimal bolt length L_(opt).The L_(opt)value is slightly larger than the initial failure range(in the unreinforced condition)and can be approximately calculated by L_(opt)=(1-0.0133u)D(u is the friction angle of the soil,and D is the tunnel diameter)in practical ***,a simplified theoretical model was established to analyse the stability of reinforced tunnel faces,and the results are in good agreement with both laboratory tests and numerical *** proposed model can be used as an efficient tool for the design of face bolts.
维普期刊数据库