盾构隧道下穿变电站建筑物沉降数值模拟分析

Numerical Simulation Analysis on Settlement Caused by Shield Tunneling Under-crossing Substation Building

变电站建筑物稳定性是电力设备可靠安全运行的关键,而变电站建筑结构附近的隧道开挖施工产生不均匀沉降造成建筑结构开裂破坏是影响变电站土建结构稳定性的重要原因。通过采用数值模拟方法,探讨了隧道开挖对既有变电站结构沉降的影响,研究了隧道埋深、隧道与变电站距离等影响因素下变电站及其下部土层的沉降特征。结果表明在没有变电站建筑物影响下,盾构隧道开挖引起的地表沉降基本呈现出正态分布,随着隧道埋深的增加,地表沉降影响范围逐渐增大,沉降值也逐渐增大,但增大的幅度有所收窄。当建筑物位于隧道轴线正上方时,土建结构沉降值较大但不均匀沉降差却可以忽略不计,呈现出整体下沉趋势;当建筑中心与隧道轴线相距1 D(洞径)时,沉降大且不均匀明显;而当建筑中心相距4 D时,变电站的沉降值和不均匀沉降均较小,更有利于变电站的保护。

The stability of the substation building is the key to working reliably of the power equipment.And it is the key factor of building stability that nonuniform settlement caused by tunnel excavation around substation.The building settlement characteristics and its influence factors such as tunnel depth,distance between building and tunnel have been researched by numerical simulation.The research showed that ground settlement is a normal distribution when there aren’t building.The settlement value and influence range have increased as increase of tunnel depth,but increase amplitude have decreased.There are large settlement but negligible nonuniform settlement when the building is located above the tunnel directly.And there are large settlement and nonuniform settlement when distance between building and tunnel is only 1 time of the tunnel diameter,but settlement and nonuniform settlement are smaller when distance between building and tunnel is 4 times of the tunnel diameter,which is more beneficial to stability of the substation building.