Numerical Analysis For Influnce Of Foundation Collaps On Buried Pipelines

As material basis of industrial and agricultural production and urban lifetransport for survival and development, buried pipelines are used in watersupply and drainage, oil, gas and heating systems. The foundation is one of themajor causes of the collapse for buried pipeline damage, so the influence offoundation collapse analysis on buried pipelines is an important issue imperative.In this paper, by using of finite element analysis software ANSYS, consideringthe pipe-soil interaction, the buried pipelines are numericaly simulated duringthe foundation collapsing.Considering the nonlinearities of pipe and soil, contactnonlinearity, and nonlinear large deformation, the distributions of stress vs.displacement of buried pipelines are analysed in depth during the foundationcollapsing. The main conclusion are summerised as follows:1) The damage reasons of buried pipelines during the foundation collapsingare qualitatively anslysed based on the studty and review of the theories andmethods,collection and collation of the data and material domestic and abroad.2)According to glass box model test in lab, a three-dimensional model is built by using of ANSYS software, by creating the pipe-soil contact at theinterface, and use of technology of element birth and death to simulate thegradual collapse of the foundation, the developing regulation of stress anddisplacement of buried pipelines is analysed during the expanding process ofsoil subsidence. By comparing the measured data with those of model box test,the accuracy of the numerical simulation method is verified.3) Through a series of cloud analysis, the dangerous section, control forceand control point of pipelines are identified.The contact state at the interfacebetween pipe and soil is researched.4) The influences of the various factors on the stress and deformation areanalysed, such as the buried depth, material, wall thickness, stiffness of soilaround pipe and friction coefficient between the pipe and soil.Some valuableconclusions are drawn out, which may provide a theory support to the designand construction of pipeline.