端部锚固锚杆预应力场分布特征研究  

Distribution Characteristics of Prestressed Field of End-Anchored Bolts

作　　者：訾信 汪波[1] 喻炜 钟官峰 ZI Xin;WANG Bo;YU Wei;ZHONG Guanfeng(Key Laboratory of Transportation Tunnel Engineering,the Ministry of Education,Southwest Jiaotong University,Chengdu 610031,Sichuan,China)

机构地区：[1]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

出　　处：《隧道建设（中英文）》2023年第10期1750-1759,共10页Tunnel Construction

基　　金：国家自然科学基金项目(U2034205);四川交通科技项目(2021-MS1-030,2021-B-01)。

摘　　要：为探明端部锚固预应力锚杆在隧道围岩中所形成的压缩带应力分布特征,先结合室内试验和数值模拟手段分析单根预应力锚杆作用下的围岩响应;然后,采用ABAQUS软件研究不同预应力大小、长度及间距的锚杆群在马蹄形隧道围岩中形成的径向应力的分布规律,并对压缩带内径向应力分布规律进行进一步分析探讨。研究结果表明:1)端锚型锚杆预应力所形成的压缩带主要集中在未锚固段围岩中,而锚固段围岩中由于锚杆剪力作用会形成拉应力集中区;2)随着锚固长度的增加,压应力区明显减小,全长锚固时,仅在垫板端附近极小范围内形成压应力区,无法较好地发挥预应力的扩散效果;3)群锚预应力形成的连续压缩带厚度随间距减小明显增大,但随长度增大变化不明显;4)短锚杆更易在杆长范围围岩内形成连续压缩带,而长锚杆无法在整个杆长范围围岩内形成压缩带,其应力扩散效果有限。To investigate the stress distribution characteristics of the compression zone formed by end-anchored prestressed anchor bolts in the surrounding rock of tunnels,the response of the surrounding rock under the action of a single prestressed bolt is analyzed using laboratory tests and numerical simulations.The ABAQUS software is used to explore the radial stress distribution patterns in the surrounding rock of a horseshoe-shaped tunnel anchored by bolt groups with various prestresses,lengths,and bolt spacings.The results reveal the following:(1)The compression zone formed by end-anchored prestressed bolts primarily concentrates in the unanchored section of the surrounding rock.By contrast,the anchored section experiences a tensile stress concentration due to the shearing effect of the anchors.(2)With increasing anchorage length,the compression zone noticeably decreases;when full anchorage is conducted,a compression zone is formed only within a very small range near the bearing plate,limiting the diffusion effect of prestress.(3)The thickness of the continuous compression zone formed by a group of prestressed anchors considerably increases as the bolt spacing decreases.However,it shows less variation with increasing anchor length.(4)A continuous compression zone is more likely to form by short anchors within their range,whereas it cannot be formed by long anchors within their range,thereby limiting the effectiveness of stress diffusion.

关 键 词：端部锚固预应力锚杆 分布式光纤 群锚压缩带 应力扩散 应力场 ABAQUS软件 

分 类 号：U45[建筑科学—桥梁与隧道工程]