类矩形截面隧道开挖诱发邻近管线变形模型试验与数值模拟研究

Study on model test and numerical simulation for deformation of adjacent underground pipeline caused by excavation of quasi-rectangular tunnel

针对类矩形等异形截面隧道施工逐年增多,而针对类矩形隧道开挖诱发邻近地下管线变形的室内模型试验研究还非常少见,目前仅就圆形隧道施工对邻近构筑物影响的室内模型试验做了较多研究。基于类矩形截面隧道开挖收敛位移模式,建立类矩形隧道开挖诱发邻近地下管线变形的模型试验系统,包括类矩形隧道开挖模拟装置、管线模拟装置、管线位移测量体系以及模型试验数据采集体系等。通过4个液囊排水模拟类矩形隧道开挖掘进过程,实时记录邻近地下管线的沉降变形、管线截面内力,以及类矩形隧道开挖表面接触力和管线表面土压力变化,分析类矩形隧道开挖诱发邻近地下管线沉降变形以及管线截面内力分布与发展规律。试验表明:管线沉降随着隧道液囊的排水缓慢增加,隧道表面和管线表面土压力缓慢增加后趋于稳定。针对不同的管线埋深、管线外径进行多种工况模型试验,结果表明:在管线外径相同的工况下,随着管线埋深的增加即隧道与管线间距变小,管线沉降变形增加,管线内力增加;在管线埋深相同的工况下,随着管线外径的增大,管线沉降变形减小,管线内力增大。同时,建立相应工况的数值模型与模型试验结果进行对比,具有较好的一致性。

At present,more research had been done on the indoor model test of the influence of soft soil circular tunnel construction on adjacent structures.However,the indoor model test for the deformation of adjacent underground pipelines caused by the excavation of quasi-rectangular-irregular section tunnel was still rare to study.Based on the quasirectangular-shaped section tunnel excavation convergence displacement mode,a model test system for the deformation of adjacent underground pipelines induced by quasi-rectangular tunnel excavation was established,including quasi-rectangular tunnel excavation simulation device,pipeline simulation device,pipeline displacement measurement system,and model test data collection system,etc.The excavation process of quasi-rectangular tunnel was simulated by four liquid bags drainage,and the settlement deformation of adjacent underground pipelines,the internal force of pipeline section,and the surface contact force of excavation-like tunnel excavation and the earth pressure of pipeline surface were recorded in real time.Tunnel excavation induced settlement deformation of adjacent underground pipelines and internal force distribution and development of pipeline sections.It was found that the settlement value of pipelines increased slowly with the drainage of tunnel sacs,and the soil pressure on the surface of tunnels and pipelines increased slowly and then stabilized.In addition,a variety of working condition model tests were carried out for different pipeline depths and pipeline outer diameters.The results showed that under the same working conditions of pipeline outer diameter,as the pipeline depth increased,the distance between the tunnel and the pipeline became smaller,as the settlement deformation of the pipeline increased,the internal force of the pipeline increased.Under the same working conditions of the buried depth of the pipeline,as the outer diameter of the pipeline increased,the settlement deformation of the pipeline decreased,and the internal force of the pipeline increased.At the same time,the numerical model of the corresponding working conditions was established and compared with the model test results,and good consistency was obtained.