断层带处公路隧道横断面抗震分析

Study on Transverse Seismic Response of Highway Tunnel in Fault Region

嘎隆拉隧道是西藏扎墨公路的控制性工程,隧道处于高烈度地震区。根据扎墨公路嘎隆拉隧道地震安全性评价报告和地勘资料,运用Newmark隐式时间积分有限元法并采用黏弹性人工边界,对隧道穿越断层带时的衬砌结构进行了瞬态动力反应分析,通过计算得出拱顶、拱腰、拱脚和仰拱中部的位移时程曲线,并由位移评价了隧道稳定性。计算结果表明,衬砌在地震作用下,其内力增加有限,内力最多增加8.73%。

Galongla tunnel, which is a key project of Zha - Mo highway, is located in highly seismic region. On basis of the seismic evaluation reports of the tunnel and the geological prospecting data, the authors make analysis on the transient dynamic response of the tunnel lining in fault region by means of Newmark＇s step-by-step implicit integration FEM method and artificial viscous-spring boundaries. By means of calculation, the authors obtain the diachronic displacement curves of the crown, arch waist, arch foot and the central part of the invert. Furthermore, the authors assess the stability of the tunnel on basis of the displacement. The calculation results demonstrate that the increase of the internal force of the lining in earthquake is limited with the maximal increase being approximate 8.73%.