| As urbanization continues to develop, in the process of building the soft soil area of environmental protection have become increasingly demanding, Deep foundation excavation requires not only consider their own security and stability, but also scruples the impact on the surrounding building structures. Currently on soft soil foundation stability control has gone from strength to play to control the deformation control, the time factor is gradually taken into account. In order to study this problem better, Introduction the creep theory, use appropriate elastic viscoplastic constitutive model to study soil deformation of deep foundation, in order to get the soil deformation properties that considered the time factor. Mainly done the following aspects of work:(1) Deformation by summarizing research status in time effect, summarize various research approaches and results, in-depth analyzed the time effect level in various engineering problems, this research indicates the direction and provide the basis.(2) On the basis of the investigation of the geology in the pit, excavation engineering design and the characteristics to collate the actual monitoring data, and based on the results of the time-effects to analyst and evaluate.(3) After the excavation of the first step make the max monitoring subsidence value as the orthogonal indicators, for Kelvin viscosity and Kelvin shear modulus to design the orthogonal,Through the analysis of test results, determining a set of soil physical parameters that near the indicators of the test and makes adjustments to optimize, determining a set of parameters as the inversion results when the error is relatively small.(4) Make the maximum lateral deformation value of the pile as a safety control targets, application FLAC3D numerical simulation method to analyze the actual project then comparison with field data. On the basis of the qualitative analysis quantitative analysis of deep foundation construction process about normal excavation timely support and over break, the pit structure variation with time to predict the safety storage time of deep foundation pit. |
