A Numerical Analysis Of Working Behavior Of Underground Pipelines Affected By Large Excavations In Soft Soils

Ground settlement and soil movement induced by large excavation will have negative influence on surrounding buried pipeline. Applying the traditional design theory (strength-controlling design) and routine construction technology, there is inevitable difficulty about protecting the buried pipeline. The design of foundation work shall be converted from strength-control mode to deformation-control mode in order to meet the increasingly strict environmental demands. Although many researchers have work a lot in the environment impact of excavation, but for foundation pit supporting, soil and underground pipeline interaction, there are still many questions worth exploring.On the basis of reviewing and summarizing the related research of deep excavation, geogrid and underground pipelines at home and abroad, the Hardening-Soil model and contact surface model were adopted to simulate the characters of soil and the interaction of pipeline and soil respectively, a 3D finite element model based on large excavation by Plaxis 3D Tunnel, to research the impact on underground pipeline induced by excavation and loading, and geogrid to reduce uneven settlement. The underground pipeline horizontal displacement, vertical displacement and internal force were considered in the paper affected by different number of channels, diameter, and location, and construction procedures, soil modulus, pit size, also consider differential settlement of pipeline affected by different loading, geogrid layers and stiffness of geogrid.Through the study of the paper, to get the basic knowledge of deformation of nearby underground pipelines affected by large excavation in soft soil, which has a certain degree of reference significance for the protecting design of pipeline in actual excavation and future research.