Study On The Impact On The Pipeline Of Excavation Of Foundation Pit And The Evaluation And Protection Measures

With the further acceleration of urbanization in China, undergroundspace development gains more attention in the urban construction,Excavation of the foundation pit inevitably causes interference to itssurrounding buildings and underground pipelines. Underground pipeline isregarded as the lifeline of a city, therefore, deep research in the impact ofunderground pipelines due to excavation of the soil and the respondingprotective measures has significant theoretical and practical significance.Based upon the foundation pit project of the South East Outer RingRoad Station of Metro Line1in Ningbo, through the establishment of thefinite element model, the paper is aimed to do a system study in the impacton the underground pipeline’s displacement and force as a result ofexcavation of the foundation pit.The prime contents of this research are asfollows:(1) When different constitutive models of soil were compared,combined with soft soil rheology, the final choice is D-P constitutive model, which is used to simulate the impact of excavation of foundationpit on the underground pipelines.(2) Analyze the factors affecting pipeline’s property in the process ofexcavation. The factors are as follows: the location of the pipeline and thefoundation pit, soil property, support cases and the stiffness of thediaphragm wall. As a consequence, we get the corresponding contrastcurve of displacement, which provide a dependable basis for assessing thesafety and protection measures pipeline.(3) Four underground pipelines in the South East Outer Ring RoadStation of Metro Line1in Ningbo are applied to do the settlement valuecomparison between the FEM simulation results and monitoring data, inorder to test whether the model is validity or not and analyze the causes ofsuch results.(4) Summarize the safety criterion and methods of undergroundpipeline; determine the security situation of the underground pipelines inthe South East Outer Ring Road Station of Metro Line1in Ningbo andpropose pipeline protection measures.