汶川地震断层破碎带段隧道结构震害分析及震害机理研究

Study on the characteristics and mechanism of seismic damage for tunnel structures on fault rupture zone in Wenchuan seismic disastrous area

基于汶川地震公路隧道震害资料,通过数据统计分析得出造成断层破碎带段隧道结构震害的原因主要有:断层错动、围岩条件软弱及断层破碎带宽度;断层破碎带段隧道结构震害特征为:错动断层隧道出现了二衬垮塌、隧道垮塌等严重震害类型;未错动断层隧道未出现二衬垮塌、隧道垮塌等严重震害类型。通过数值模拟及现场震害分析,结果表明:错动宽断层破碎带隧道震害最严重,不但引起二衬垮塌,而且引起隧道垮塌,是抗震设防的重点;错动窄断层破碎带隧道震害较严重,会引起二衬垮塌,也是抗震设防的重点;无错动宽断层破碎带隧道震害较轻,不会引起二衬垮塌等严重震害。错动断层隧道不但要进行横断面抗震设防,还要进行纵向抗震设防,而且纵向抗震设防是必须的;无错动断层隧道可通过横断面抗震设防解决。研究成果对过断层隧道的抗震技术有着重要的意义。

Based on the damage reports of highway tunnels in Wenchuan earthquake, statistical analysis is conducted and the main reasons of tunnel structure damage in fault rupture zone are determined as fault dislocation, weakness of surrounding rock and width of fault rupture zone. The damage characteristic of tunnel structures in earthquake are that serious damage, such as secondary lining collapse and tunnel collapse, can be found when fault dislocates, but it will not emerge when fault is stable. Based on the numerical simulation and in-situ damage analysis results, it can be concluded that when fault is wide and it dislocates, tunnel structure damage in fault rupture zone is the most serious wide dislocating area. Both secondary lining collapse and tunnel collapse will emerge, so the precaution should be taken in priority. When fault is narrow and dislocates, tunnel structure damage in fault rupture zone is also critical. When fault is wide and stable, no serious damage like the collapse of the secondary lining will emerge. When fault dislocates, both cross sectional precaution and longitudinal precaution should be taken in tunnel engineering, especially the longitudinal one. When fault is stable, only cross sectional precaution should be taken. The research results can provide reference for anti-seismic precaution of tunnel across fault rupture zone.