让压(组合)锚杆在挤压大变形隧道中的力学特性试验  

Experimental Study on Mechanical Characteristics of Yielding(Combined)Bolt in Extrusion Large Tunnel Deformation

作　　者：郭新新 汪波[2] 喻炜 王振宇[2] 王勇 GUO Xin-xin;WANG Bo;YU Wei;WANG Zhen-yu;WANG Yong(College of Environment and Civil Engineering,Chengdu University of Technology,Chengdu 610059,Sichuan,China;Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu 610031,Sichuan,China;Hangzhou Fengqiang Civil Engineering Research Institute,Hangzhou 310008,Zhejiang,China)

机构地区：[1]成都理工大学环境与土木工程学院,四川成都610059 [2]西南交通大学交通隧道工程教育部重点实验室,四川成都610031 [3]杭州丰强土建工程研究院,浙江杭州310008

出　　处：《中国公路学报》2023年第6期180-189,共10页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(U2034205);甘肃省科技计划项目(19ZD2GA005)。

摘　　要：全长黏结型长锚杆作为一种被广泛应用于治理挤压大变形隧道的支护措施,常因围岩变形过大,发生杆体断裂和垫板屈服等现象。为此,提出一种可自进式让压(组合)锚杆,通过在部分杆体上外套光滑套管形成无黏结段,使该无黏结段先于锚固系统破坏前“屈服”伸长,实现了长锚杆在全长灌浆条件下的“让压”,提升了锚固系统的整体稳定性。以新建木寨岭公路隧道为工程依托,采用自进式施工工艺,开展了全长灌浆下的10 m全长黏结锚杆和10 m让压(组合)锚杆的对比试验。试验结果显示:全长黏结锚杆轴力200 kN,超过杆体屈服荷载,且垫板在支护初期(4~5 d,围岩位移75 mm)即出现明显屈服,锚固系统整体稳定性差、可靠性低;让压(组合)锚杆因存在无黏结段,杆体轴力和垫板应力均出现下降,最终保持在一个较低的量值(130 kN和190 MPa),实现了全长灌浆型长锚杆的大尺度支护。研究成果可为大变形隧道中长锚杆的选型提供借鉴。The fully bonded long rock bolt is a kind of support measure widely used in the treatment of large tunnel deformation.However,fracturing of the rod and yielding of the plate often occur due to large deformation of the surrounding rock.Therefore,this paper proposes a combined self-propelled yield(combined)bolt.To realize the“yield”of the long rock bolt under the condition of fully grouted,the unbound segment was formed by a smooth casing on part of the rod,and the unbound segment was extended before the anchor system was destroyed.This new rock bolt can overcome the“large deformation”of the bolt under the condition of full-length grouting,and can improve the overall stability of the bolt system.Based on the newly built Muzhailing highway tunnel,self-propelled construction technology was considered to carry out a comparative test between a fully grouted 10 m hollow threaded bolt and a 10 m yield(combined)bolt.The test results show that the axial force of the threaded bolt system is 200 kN,which exceeds the yield load of the rod.Meanwhile,obvious yielding of the plate occurred at the initial stage of support(4-5 days,displacement of surrounding rock of 75 mm).The overall stability and reliability of the anchorage system are poor.However,due to the existence of the unbonded segment in the yield(combined)bolt,the axial force of the rod and the stress of the plate decreased,finally maintaining lower values of 130 kN and 190 MPa,respectively,achieving large-scale support using the fully grouted bolt.The research results can be used for reference in the selection of long bolts in large tunnel deformations.

关 键 词：隧道工程 让压(组合)锚杆 现场试验 大变形 锚杆设计 

分 类 号：U451[建筑科学—桥梁与隧道工程]