Research Of Groundwater Dynamic Analysis And The Effect Of River Levee Of Precipitation During Caisson Construction

Taking of north anchorage (caisson) and its surrounding area of Taizhou Yangtse Rive Bridge as the study area, this paper used groundwater simulation software GMS to simulate groundwater flow, and predict the discharge and the trend of groundwater level. After that, evaluate the seepage stability,Stability Against Sliding and land subsidence of River Levee.Based on collection and analysis of topography and geomorphology,geologic structure and hydrogeological condition in study area, this paper systemically expound the lithology of main stratum, existing condition, distribution regularities, circulation condition and the dynamic character of groundwater. Then, this paper ascertains the scope of simulation region and the selective zone of calculation. After generalize the aquifer hydraulic characteristic, vertical boundary and lateral boundary, the groundwater mathematical model has been founded on the basis of the hydrogeology conceptual model.Based on the mathematical model, the model is built according to the borehole data, border condition and various source/sinks items combine grid approach with conceptual model approach. Model calibration is adopted to fit parameters and then verify the model. It is indicates that: This model reflects the characteristics of the system of the groundwater , reproduce the pattern of change and transportation of groundwater, and it can give scientific supports to the prediction of the discharge,groundwater table and the control of the land subsidence.Seepage deformation is the main cause of danger in River Levee during the construction period. In order to evaluate the safety of the River Levee, predict the form and location of the seepage failure and suggest the scientific instruction to reinforce the River Levee, it is of great theoretical and practical importance to research the course of seepage deformation in the River Levee foundation. This paper make use of groundwater level that predict by the model to choose three typical section of River Levee for numerical simulation of seepage, and evaluate the seepage stability and slope stability.Another geological phenomenon that caused by construction precipitation is land subsidence. Land subsidence results from changes in the pressure borne by pore water in the soil and the effective stress borne by soil skeleton. This paper establishes land subsidence model with elastic nonlinear Duncan theory and Biot consolidation plan finite element program (BCF95), and predict the subsidence of River Levee.