针对跨断层隧道洞身段设置抗减震措施开展振动台模型试验研究。通过分析围岩与隧道结构的地震加速度响应、地震动应变反应以及隧道结构的震后破坏形态,对设置减震缝、减震层和无抗减震措施3种情况进行对比研究。结果表明:新型滑动装置在单一模型箱内能够较好地模拟断层错动,从而实现对模型系统的非一致性地震激励;断层错动能够引起隧道结构横断面大范围的破坏,因此跨断层的隧道结构必须设置抗减震措施;减震缝可以使隧道结构发生相对变位以降低结构的地震动应变值;减震层材料的缓冲作用可以削弱隧道结构因受围岩约束而产生的受迫振动,从而降低地震动应变值;减震层的减震效果优于减震缝,但是要充分发挥二者的抗减震作用,还需提高衬砌混凝土的强度;拱肩、拱脚和仰拱是隧道结构抗震加固的重点部位。研究结果有利于隧道结构新型抗减震措施的开发,以及为跨断层隧道结构的抗震设防提供参考。
Shaking table tests were conducted to simulate the anti-seismic and damping measures on tunnel structures across faults. The fault-crossing tunnel structures with an absorbing joint, with a seismic resistant layer and without any damping measures were investigated respectively for comparisons by analyzing the seismic acceleration responses of surrounding rock, the seismic strain responses and the post-seismic destructive patterns of tunnel structures. The new type of dislocation device used in the single model box was proved to be capable to simulate the faults movement perfectly and to be able to help the shake table to exert the nonuniform seismic wave excitation. The absorbing joint reduced the strain values of tunnel structures by allowing the dislocation of the linings. The forced vibration and the seismic strains of tunnel structures due to the constraint of surrounding rock were reduced by the buffering of the seismic resistant layer. The seismic resistant layer was found to better than the absorbing joint. But the effect of these two measures were to be fully displayed, the strength of the lining concrete must be raised accordingly. The arch shoulder, the arch springing and the invert arch of the tunnel were found to be the vital parts for reinforcements.