Study On Working Mechanism And Settlement Characteristics For Pilenet Composite Foundation Of Lakeside Area

Pile-net composite foundation, which is a kind of effective method to strengthen the deep soft soil foundation in recent years, has the advantages of small settlement,easy control, high stability, short time limit, convenient construction and economy.While the working mechanism of pile-net composite foundation reinforcing soft foundation is very complex, and the theoretical study is far behind engineering practice.Therefore, taking Jiujiang beltway expressway as the engineering background,this paper uses the methods of laboratory tests, field monitoring, theoretical analysis and numerical simulation to research on the working mechanism and settlement deformation regulation of pile-net composite foundation. This paper mainly carries out the following aspects of the work:1. Through the analysis of theoretical research and engineering application at home and abroad about pile-net composite foundation, the working mechanism is researched more in-depth and the mainly calculation methods of settlement and net tension are summarized.2. By obtaining soil in situ of Jiujiang beltway expressway A1 contract section of soft foundation test and taking the indoor test of liquid plastic limit, consolidation,direct shear and so on, some physical parameters of soft soil are obtained.3. Taking Jiujiang beltway expressway of soft foundation test as the engineering background, the change regulation of subgrade settlement, pile-soil stress and geogrid deformation is revealed during embankment construction based on field monitoring.4 By using the finite difference method to calculate, the deformation characteristics of pile-net composite foundation during embankment construction are analyzed and compared with the measured values. Meanwhile, through the calculation of the various design parameters(such as pile length, pile spacing, cushion thickness and geogrid floors), the deformation influence and change regulation by the parameters of pile-net composite foundation are analyzed. The design parameters of the engineering are optimized.5 The technology and economy of the soft foundation reinforced by CFG pile is analyzed. Taking Jiujiang beltway expressway as the engineering background,comparing the technology and economy of CFG pile with cement injection pile to reinforce the soft foundation, it is found that CFG pile-net composite foundation is more suitable to deal with the deep soft foundation.