Numerical Analysis Of Interaction Between Buried Pipeline And Soil Due To Tunneling

The failure of the existing pipelines due to tunnel excavation is becoming more and more serious. For reducing the risk of pipeline damage, it is particularly important to find a reasonable methodology to estimate the safety of buried pipeline.This paper takes into account soil-pipe separation and axial force of the pipeline. Upon assumption of calculation, mechanical model, boundary conditions and calculation parameters were determined for numerical simulation. Then the influences of soil types, tunnel size, distance between tunnel and pipe, as well as pipe stiffness on both internal force and the deformation behavior of the buried pipelines were investigated.The main results of the paper are obtained as follows:1.The effects of each single factor on the pipelines are:the smaller elastic modulus of the soil, the larger soil settlement, resulting in larger pipeline settlement and larger axial force and bending moment of the pipeline; the smaller tunnel diameter? the smaller soil settlement, bringing about smaller pipeline settlement, axial force and bending moment of the pipeline; the closer the pipeline from the tunnel, the narrower the soil settlement trough, producing smaller pipeline settlement, smaller axial force, and larger bending moment; the greater stiffness of the pipeline, the smaller pipeline settlement, inducing larger soil reaction force on the pipeline, larger bending moment, while the axial force goes first increasing and then decreasing.2. When pipe-soil separation is allowed, the calculated settlement, bending moment and axial force of the pipeline are all smaller than those where the pipe is sticked with the soil throughout the process of deformation.3. According to the soil-pipe relative rigidity factor K, a pipeline can be divided into rigid pipeline, elastic pipeline and soft pipeline:K<0.1, soft pipeline;0.1≤K≤100, elastic pipeline; k>100, rigid pipeline.