高地应力软岩隧道长、短锚杆联合支护技术研究  

A combined support technology of long and short bolts of soft rock tunnels under high ground stresses

作　　者：刘宇鹏 夏才初[1] 吴福宝[2] 徐晨 邓云纲[2] LIU Yupeng;XIA Caichu;WU Fubao;XU Chen;DENG Yungang(Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092,China;China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan,Hubei 430063,China)

机构地区：[1]同济大学土木工程学院地下建筑与工程系,上海200092 [2]中铁第四勘察设计院集团有限公司,湖北武汉430063

出　　处：《岩石力学与工程学报》2020年第1期105-114,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51778475);中铁第四勘察设计院集团有限公司外委科技项目(2017K74-1)~~

摘　　要：基于考虑应变软化特性的深埋隧道弹塑性解,采用锚杆中性点理论,系统地分析高地应力软岩隧道短锚杆支护失效机制,并论证高地应力软岩隧道中对锚杆长度进行加长的必要性:一方面增大锚固段的围压以提高黏结强度,另一方面增大锚杆头部和尾部处的围岩位移差以提高锚杆对围压的锚固效用。将高密度支护模式的短锚杆等效为复合岩体,同时将长锚杆对围岩的锚固作用考虑为作用在隧道洞壁处的等效支护力,建立隧道长、短锚杆联合支护力学模型,考虑锚杆和围岩的相互作用,得到长、短锚杆联合支护后的围岩特征曲线。通过对比每延米隧道锚杆用量相同情况下,普通短锚杆支护和长、短锚杆联合支护状态下的围岩特征曲线,说明了长、短锚杆联合支护策略对高地应力软岩隧道变形控制的有效性。该长、短锚杆联合支护力学模型考虑了长锚杆与围岩的相互作用,为高地应力软岩隧道长锚杆支护长度的设计提供了一种计算方法。Based on the elastoplastic solution of deep buried tunnels considering strain-softening characteristics,the failure mechanism of short bolt support in soft rock tunnels under high ground stresses is analyzed by means of neutral point theory of bolts,and the necessity of lengthening the bolts in soft rock tunnels under high ground stresses is demonstrated. On one hand,the increase of the confining pressure on the anchor section can improve the bonding strength between the rock and the bolt,on the other hand,the enhancement of the difference of the surrounding rock displacements at the head and end of the bolt helps to improve the anchoring effect of the bolt to the surrounding rock. By taking the supporting body with intensive short bolts as composite rock mass and the support of long bolts as an equivalent support force acting on the tunnel wall,a combined support model of long and short bolts is established. The characteristic curve of the surrounding rock supported by long and short bolts is obtained by considering the interaction between the bolts and the surrounding rock. Comparison between the characteristic curves of the surrounding rocks,respectively reinforced by short bolts and the combined support technology of long and short bolts with the same amount of bolts per meter of the tunnel,illustrates the effectiveness of the combined support technology for deformation control of soft rock tunnels under high ground stresses. The combined support technology of long and short bolts,considering the interaction between long bolts and the surrounding rock,provides a calculation method for the support length of long bolts in soft rock tunnels under high ground stresses.

关 键 词：岩石力学 高地应力 软岩隧道 锚杆 长锚杆 失效机制 

分 类 号：TU45[建筑科学—岩土工程]