软土地层双线盾构隧道横断面地表沉降预测模型

Forecasting Model for Transverse-section Settlement Induced by Bi-tunnel Shielding in Soft Soil Stratum

以我国软土地区双线盾构隧道施工后的地表沉降为研究对象,采用工程实证研究方法,通过调研的隧道地表沉降测线实测数据,对双线隧道横断面布置方式进行划分,研究了横断面地表沉降槽形态和预测方法.研究表明:双线隧道布置方式可分为双线平行、上下错开和竖向重叠三种;当双线隧道平行布置时,地表沉降槽形态与隧道覆土厚度和隧道轴线间距有关,呈“W”和“V”两种形态;当双线隧道上下错开和竖向重叠布置时,沉降槽均呈“V”形.针对双线隧道不同的布置形式,以高斯函数为基础提出了横断面地表沉降预测模型,根据实测地表沉降的回归拟合得到模型参数的取值方法.

In this paper,the subsidence induced by bi-tunnel shielding in soft soil was investigated,the empirical analysis method was adopted.Measurement data of tunnel surface settlement trough lines were collected by the survey of the running tunnels cases.The layout of bi-tunnel was divided into three different types,the characteristic and forecasting method of transverse-section settlement trough were studied.Research shows that the bi-tunnel can be arranged in parallel,staggered and overlapping relations.The settlement trough could be"W"-shaped or"V"-shaped when two tunnels are in parallel relation,the shape of settlement trough is related with the covering depth and the spacing of bi-tunnel.The settlement trough is"V"-shaped when two tunnels are in staggered and overlapping relations.Based on Gaussian function,the forecasting model for transverse-section settlement trough is proposed when two tunnels are in parallel,staggered and overlapping relations.Based on the measurement subsidence data,the determination methods of model parameters are set up by regressive analysis.