摘要
以西部山区覆盖大量松散崩塌堆积体的某公路隧道(S隧道)为工程背景,利用振弦式传感器监测隧道初支与二次衬砌间接触应力和二衬混凝土应变,讨论隧道二衬受力特性,为相似隧道工程二衬设计、施工提供参考。结果表明:覆盖松散堆积体的S隧道二衬可有效承担围岩压力,且于二衬施作完成50d后应力基本保持稳定;二衬存在一定的偏压受力,其左幅所受应力大于右幅;隧道二衬混凝土应变起始为拉应变,随时间增长,应变转为压应变并逐渐趋于稳定;二衬混凝土所受较大压应变主要位于隧道拱腰肩位置,与初支和二衬间接触应力最大值位置具有一定对应关系;初支与二衬间最大接触应力0.1MPa,二衬混凝土最大压应变28με,各监测值均处于二衬结构安全受力范围内,该覆盖松散堆积体隧道施作的二次衬砌结构受力安全可靠。
A Case study of a loose deposit surrounding tunnel （S tunnel） in western mountain area was carried out. The contact stre^s between preliminary support and secondary lining, the strain change in the secondary lining concrete was monitored with vibrating-wire sensors. The mechanical characteristics of secondary lining were discussed. The analysis results could be referred by secondary lining construction and design in similar loose deposit surrounding tunnels. The results show that the secondary lining of S tunnel bears the transfer stress of surrounding rock, and the stress is stable after 50 days of secondary lining construction. Biasing force is found in the secondary lining that the left stress is greater than the right. Secondary lining concrete strain is becoming stable after experiencing a conversion from tension strain to compressive strain. The large strain in secondary lining concrete is mainly located at the waist and shoulder of tunnel, which has a certain relation with the position of contact stress between primary support and secondary lining. The maximum contact stress between primary support and secondary lining is 0. 1MPa, the maximum secondary lining concrete strain is 28p, s, the monitoring values are within the secondary lining safe range, the secondary lining structure of tunnel which is covered loose deposit is safe and reliable.
出处
《工程勘察》
2018年第2期12-16,共5页
Geotechnical Investigation & Surveying
基金
交通部西部交通建设科技资助项目(2013318J01100)
甘肃省科技支撑计划项目
关键词
松散堆积体
隧道
二次衬砌
监测
受力特性
loose deposits
tunnel
secondary lining
monitor
mechanical characteristics
