The Analytical Solution Of Composite Fountiodan With Granular Columns Under Vacuum-Surcharge Preloading

There were large areas of so ft clay whose engin eering behavior was poor in China, and with the development of the national economy, construction of infrastructure projects was higher in China. Because of the soft clay layer has a large water content, high compressibility, low strength, poor per meability and low bearing capacity, it was hard to meet structures in the construction and eliminate excessive settlement. So it was necessary to make corresponding processing of soft ground.As a kind of drainage consolidation methods, vacuum-surcharge preloading have a greater advantage for its duration, effects, technology, cost and then had a wide range of applications. Base on the former researchers’ s work, this paper researched the ques tions above composite founda tion consolidation under vacuum-surcharge preloading. All work done was as follows:(1) By establishing a model to study the consolidation proble m that composite foundation under the condition of vacuum-surcharge preloading. A consolidation study of the composite foundation was analyzed, consider the impact of construction disturbance, the vacuum degree was linear decrease along the foundation depth, and the horizontal permeability coefficient of soil was parabola distribution pattern. A analytical solution was obtained for com posite foundation under vacuum-surcharge preloading, and s and the two exceptions were calculated, the solution of rationality was verified.(2)By two-dimensional finite element numerical simulation, this theis researched the questions above linear and nonlinear of composite foundation under the condition of vacuum-surcharge preloading.(3) Comprative study on composite foundation under the condition of vacuum-surcharge preloading and vertical sand foundation under vacuum-surcharge preloading; Analysis the influence factors of consolidation, such an penetration, modulus of the pile and permeability of pile soil; Drawing calculation curves and graphs of composite foundation under the condition of vacuum-surcharge preloading.