高烈度地震区公路双连拱隧道地震动力响应研究

针对目前尚未对高烈度地震区双连拱隧道这种特殊的结构形式进行具体深入的动力响应研究的现状,从土-结构相互作用模型出发,运用数值分析方法对连拱隧道进行了三维弹塑性分析,主要研究水平方向上传播的剪切波所引起的双连拱公路隧道的地震动力响应。从计算结果看出,随着埋深的增加,双连拱隧道衬砌的水平位移逐渐减小,衬砌内力逐渐增大,而变化趋势逐渐平缓;随着中墙厚度的增加,隧道衬砌水平方向的位移峰值逐渐增大,因此建议采用2.2 m厚中墙。研究结果表明,连拱隧道衬砌的仰拱、墙脚及拱肩为抗震的薄弱环节。

Dynamic Seismic Responses of a Double-arch Tunnel in High-intensity Earthquake Region

Based on soil-structure dynamic interaction model with elasto-plastic characteristics of materials taken into consideration,a three-dimensional numerical analysis by adopting time domain integration algorithm was applied to study the seismic responses of a double-arch highway tunnel under the action of horizontal seismic wave.Results indicated that horizontal displacements of the tunnel decreased while the internal forces of it increased with the increase of overburden;peak values of horizontal displacements of tunnel lining increased with the increase of center wall thickness.A 2.2m thickness is recommended for the center wall.Weak portions of the tunnel under earthquake are the invert,wall bottom and arch spandrel.