| With economic development, due to the large population, dense building,intricate kinds of underground pipelines, excavation’s depth of urban constructionincreasing, the security issues and the impact on the surrounding environment of deepexcavation became an important issue of geotechnical engineering. In this paper, onthe basis of previous studies, this topic what impact deep excavation makes onsurrounding underground pipelines is studied and analyzed by finite element softwareABAQUS. Main contents and conclusions are as follows:1. Introduce the application of finite element software--ABAQUS in foundationexcavation, at the same time the three-dimensional finite element unit type, theconstitutive model selection, initial stress settings and key technologies of excavationsteps were described.2. Using ABAQUS software build three-dimensional finite element model madeup of soil, retaining structures and underground pipeline. Study different factors’impacting on the deformation of underground pipelines, such as step excavation,different material pipes, and different distance from the pit, different embedmentdepth and the surrounding heap load and so on. Through numerical simulation resultscompared and analyzed,we can come to the conclusion that the deformation ofthe pipeline excavation increases with the depth increasing of excavation; deformationis related with the modulus of elasticity; sphere of pit influence on the adjacentpipeline roughly is the excavation depth’s three times; during excavation as far aspossible minimize heap load around foundation, control impact on the surroundingenvironment caused by excavation, reduce accidents.3. In combination with engineering examples, using of ABAQUS the model thatis three-dimensional within the brace supporting structure excavation is established.Through the analog and specific monitoring data, the accuracy of model was verified.Through studying excavation effect on the spatial displacement of the adjacentunderground pipelines, we can come to the conclusion that the deformation of thepipeline has an obviously relationship with orders of excavation and on the excavationend. The sphere where the pipe line affected by pit angle is in the range of1.5timesthe depth of excavation. At the same time the reasonable reinforcement range ofpassive zone were compared and analyzed, and come to the conclusion that using passive zone soil reinforcement can effectively reduce its displacement around buriedpipelines. Combined with the actual situation of the project, that the reinforcementrange of depth of6m and width of7m is the most economical under the premise ofreinforcing effect being satisfied.Through the preliminary study, it made an initial understanding about the impacton underground pipelines produced by a large excavation, provide theoretical basisfor the future information technology guiding engineering practice, and for the designof protecting underground pipelines around and future research for the actualexcavation works have a certain reference value. |