Analysis On Strengthening Deep Soft Foundation By Vaccuum Surcharge Preoading

Vacuum-surcharge preloading method is one of the effective methods of dealing with soft soil foundation, this method has obvious advantages than other methods in reducing the cost, shortening the construction period, safety, strengthening big depth. With the continuous development of infrastructure construction in China, more and more buildings and structures need to be built on soft soil foundation, vacuum- surcharge preloading method is therefore widely used. This method since its birth in the 1950 s, many scholars at home and abroad, had a lot of research on its application, and achieved fruitful results. but, at present there are still some problems has not been well solved. In this paper, on the basis of previous studies, using the vacuum - surcharge preloading treatment of deep soft soil foundation field test, analyze the test data, and combined with numerical simulation, on the role of vacuum-surcharge preloading method for further exploration. The main research contents and work is as follows:(1) Collected research literatures at home and abroad of vacuum-surcharge preloading method, summarized the method dealing with soft soil consolidation theory, the reinforcement mechanism, deformation characteristics, etc.;(2) Based on actual project, describes in detail the design and construction and test plan of vacuum-surcharge preloading method, analyze the test data from project, get the change rule about under membrane vacuum, drainage plate vacuum, the surface subsidence, deep subsidence of soil, the surface displacement and deep displacement of soil, pore water pressure;(3) Make experiment contrast on soil moisture, void ratio, and vane shear strength index before and after the reinforcement, calculate final settlement of the soil and the degree of consolidation, according to demonstrated the effect of vacuum-surcharge preloading method;(4) Summarizes the Biot consolidation theory of finite element, use the geotechnical professional finite element software MIDAS/GTS NX, establish two-dimensional plane strain finite element model, and put forward the effective method to simulate the vacuum load, for simulating actual working condition, and the simulation results compared with the measured data, and demonstrate the validity of simulation;(5) On the basis of the above study, analysis the vacuum degree and parameters of band drain what can influence the effect of vacuum-surcharge preloading method, conclude the soil deformation law, provide a reference for future similar projects.