Displacement Controlled Model Test Study On Influence Of Tunneling To Surrounding Environments

With rapid development of tunnel construction technology and urban infrastructureconstruction, tunnel construction has found an increasingly wide utilization in municipalworks. However, urban narrow space inevitably leads to influence to surroundings bytunnel construction. In recent years, cases of severe damage to existing structure byinappropriate construction method, such as ground subsidence, building incline or evencollapse, have appeared frequently. Therefore, influence to surroundings by tunnelconstruction has become significant part of geotechnical engineering research.Main research methods of geotechnical engineering include numerical simulationand model test. Compared with numerical simulation, model test can simulate situationon constructing scene more realistically, and provide certain reference to the latter.Nowadays, most geotechnical engineering model tests aim at studying constructionparameter and share the same design principles with site construction method. On thecontrary, a new way of model test for researching influence to surroundings by tunnelconstruction, which is based on displacement control method and neglects constructionprocess, is provided in this paper. Main content of this paper includes the followings:(1) Determine model test plan based on displacement control method, with controlmethods of soil material density and homogeneity perfected and in order for repeatabilityof the test. Accomplish related physical tests of soil material in order to provide parameter reference to model test and follow-up numerical simulation.(2) Develop model test device according to model test principle and similarityrelation.(3) Determine the whole operation process of model test. Respectively make modeltest plans of Green Field verification, influence to piles near tunnel construction andtunnel crossing highway on parameters such as soil depth, soil layer relative density,horizontal distance of the pile, etc. Accomplish model tests and analyze the results.(4) Build FEM models of model tests and carry out numerical simulation of the FEMmodels with Gleaves software and Cyclic Mobility constitutive model. Compare resultsof model tests with those of numerical simulation.