Discussion Of Some Problems About Foundation Pit Engineering During Design And Excavation

This thesis discusses the scheme selection and optimization, calculation of earth pressure and environmental influence of foundation pit. The selection of foundation pit excavation scheme is a multi-objective decision, which including confirming decision objective, working out alternative decisions and decision choosing. This thesis uses fuzzing mathematics decision-making theory to choose scheme; basing on design variable, objective function and constraint conditions, figures out mathematic model, and uses genetic evolution to optimize the scheme; according to the correlation of the earth pressure of enclosing construction and the deformation, figures out a non-linear earth pressure model which considered deformation effect, analyzes and estimates the concepts and conditions of water-soil united method and water-soil respectively; the dominating affect factors of foundation pit environmental effect are dewatering and deformation of enclosing structure, as the result of the immaturity of the enclosing structure deformation theory, this paper introduces the conceptual design to solve the environmental problem.Secongdly, this thesis discusses some problems about earth excavation, monitoring and crash program in foundation pit engineering. Basing on rheological property analyzes the deformation during excavation, applies space-time effect to control the stability and deformation of foundation pit; demonstrates the necessity and importance in monitoring; crash program is an important item during excavation, which should be determined before excavating; a lot of uncertainties and the fuzzfy of the geologic condition, the predictability of engineering design, the variance of climatic condition and the cooperation of multi- corporation make it is very important to dynamic management, this thesis gives the argument about it through an example.