正交型立体交叉隧道的动力响应研究

Study on Dynamic Response of Orthogonal Overlapped Tunnel

随着更多复线工程的修建或者受地质条件、既有建筑物的限制以及城市地下空间综合开发的需求,不可避免的会出现许多近接或者交叉的隧道。为解决正交型立体交叉隧道结构地震动力响应特性及相互影响规律等问题,在单向El地震波作用下完成了3种地震烈度、5个工况的交叉隧道振动台试验,并分别对正交型立体交叉隧道中上跨和下穿隧道环向及轴向应变在不同加载工况下的应变峰值进行分析研究。试验结果表明:1)地震烈度越高,隧道各特征点的地震环向应变越大,下穿隧道环向应变峰值整体大于上跨隧道;下穿隧道边墙部位向应变峰值最大,下穿隧道仰拱部分次之,其次是上跨隧道的仰拱与边墙部分应变峰值。2)当地震烈度较小时,两交叉隧道的环向应变峰值基本持平。3)当地震烈度较大时,下穿隧道的环向应变峰值远大于上跨穿隧道。下穿隧道轴向应变峰值整体大于上跨隧道,且上跨隧道仰拱轴向应变峰值最大,上跨隧道仰拱次之,上跨隧道与下穿隧道拱顶轴向应变峰值最小。最后对上跨隧道与下穿隧道的动力响应规律进行了对比分析。

Due to the construction of more double-track projects, limitation of geological conditions and existing buildings and the demand of comprehensive development of urban underground space, there will inevitably be many close or overlapped tunnels.In this paper, the seismic dynamic response characteristics and interaction law of the overlapped tunnel structure are discussed.The vibration platform tests on three seismic intensities and five working conditions are completed under the action of seismic waves.The peak strain values of the circumferential and axial strains of the upper and lower tunnels under different loading conditions are analyzed and studied.The test results show that:(1) The higher the seismic intensity, the greater the seismic hoop strain.(2) The circumferential strain peak value of the underpass tunnel is larger than that of the overpass tunnel;the circumferential strain peak value of the underpass tunnel sidewall is the largest, and the part of the underpass tunnel inverted arch is the second large, followed by the part of the overpass tunnel inverted arch and sidewall.(3) When the seismic intensity is small, the peak value of circumferential strain of the two cross tunnels is basically the same.(4) When the seismic intensity is large, the peak value of the circumferential strain of the underpass tunnel is much larger than that of the overpass tunnel.(5) The peak value of axial strain in the underpass tunnel is larger than that in the overcross tunnel, and the peak value of axial strain in the inverted arch of the overcross tunnel is the largest, followed by the inverted of the overcross tunnel, and the peak value of axial strain in the crown of the overcross tunnel and the underpass tunnel is the smallest.Finally, the dynamic response laws of the overcross tunnel and undercross tunnel are compared and analyzed.