Experiment Study On The Supporting Capacity Behavior For Deep Mixing Pile Composite Foundation

Deep Mixing Pile is a new technique of reinforcing foundation which has a lot of advantages. With the construction of numerous foundation projects, the application of Deep Mixing Pile is more extensive. However, being sluggish in the theory and unmature in the construction management, the application and development of Deep Mixing Pile is restrained. In this dissertation, based on experiments, the mechanical behaviors of the soil between piles are studied. A more reasonable method computing the bearing capacity is presented. Theoretical formula is derived to compute the lateral frictional resistance of single pile. Finally, the numerical analysis for single pile and group piles are done by with FEM. The main contents are as follows: 1.Field tests of the reinforced foundation of commence and living building with Deep Mixing Pile. In a practice project, field test is done. The laws of the deformation characteristics in consolidation and the stress-ratio of pile are summed up with the monitoring data. It provides reliable basis for the application and the theoretical research of Deep Mixing Pile. 2. On the premise that the materials of the piles are uniformity, the theoretical computing formula of the effect length of the single pile in composite foundation has been deduced. Based on the formula which is used to compute the lateral resistance of single pile deduced by Wang Qitong, a formula is setup whose precondition is that the pile and the lateral soil directly around the pile deform in-phase. On the basis of that the contact stress of the foundation is equal ,a formula that can be used to conform the stress-ratio of the composite ground is set up, on the same time, the principles of the deformation harmony of the soil and the piles in the composite ground are also discussed. Combining with results of this test, a formula which can calculate the bearing capacity that considering the effect of group piles of the composite ground is also deduced. 3．Build model .The model of the interaction between piles and soil is built based on the interaction between piles and soil, the program is written with Fortran90 language. The stress ratio and load-transfer and information are researched through 2 piles group, 4 piles group and 9 piles group. The relationship between mechanic characteristics of composite ground and the length, the distance, elasticity modulus and replacement percentage of piles are discussed. The results of computing analysis has been contrast to the experimental data. 4．Considering the conformity of piles and soil, present propositions that can optimize...