【摘要】 为研究隧道开挖引起的地表沉降规律,运用PFC2D软件模拟Trapdoor试验,通过沉陷门下沉对双线隧道开挖引起的地表沉降规律及影响因素进行了系统研究。基于休止角试验和单Trapdoor模型试验得到数值模型的计算参数,通过开展单Trapdoor数值试验获取地表沉降曲线,拟合得到单线隧道开挖引起的地面沉降Peck公式参数。开展同时开挖的双Trapdoor数值试验,利用单Trapdoor参数叠加得到双线隧道开挖引起的地表沉降预测公式,并与简单叠加公式的拟合结果进行对比。最后进行先后开挖的双Trapdoor数值试验,揭示了隧道间距、埋深和双线隧道开挖顺序对地表沉降的影响规律。结果表明:随着隧道埋深的增加和隧道间距的减小,地表沉降曲线由"W"形态向"V"形态过渡;先后开挖工况下双线隧道引起的地表沉降曲线呈非对称分布,地表沉降量最大值出现在先行隧道一侧,且随着隧道埋深的增加,地表沉降曲线两侧最大值的差异有增加趋势;Peck公式拟合结果与离散单元法(DEM)数值模型和模型试验结果吻合较好,可用于双线隧道开挖引起的地表沉降预测,具有重要的理论指导和工程意义。更多还原

【Abstract】 In order to study the law of surface settlement caused by tunnel excavation,the Trapdoor test was simulated using PFC2 D software,and the surface settlement law and its influencing factors caused by double-line tunnel excavation were systematically studied by subsidence door sinking.The calculating parameters of numerical model were gotten based on repose angle test and single Trapdoor model test.The surface settlement curve was obtained by carrying out single Trapdoor numerical test,and Peck formula parameters of surface settlement caused by single-line tunnel excavation were fitted.The double Trapdoor numerical experiment of simultaneous excavation was carried out.The prediction formula of surface settlement caused by double-line tunnel excavation was obtained by superposition of single Trapdoor parameters,and the fitting results were compared with those of simple superposition formula.Finally,the double Trapdoor numerical experiments of excavation were carried out,and the influences of tunnel spacing,depth and excavation sequence of double-line tunnels on surface settlement were revealed.The results show that with the increase of tunnel depth and the decrease of tunnel spacing,the surface settlement curve transits from "W"shape to "V"shape.The surface settlement curves caused by double-line tunnels under excavation conditions are asymmetrical,and the maximum surface settlement occurs on the side of the first tunnel.With the increase of tunnel burial depth,the difference of maximum value between two sides of surface settlement curve tends to increase.The fitting results of Peck formula are in good agreement with DEM numerical model and model test results.It can be used to predict surface settlement caused by double-track tunnel excavation,and has important theoretical guidance and engineering significance.更多还原