提高桩承载力的灌浆法研究

THE STUDY OF INJECTING METHOD FOR ENHANCING LOAD BEARINGS OF PILES

采用室内试验和实体模型试验的方法，研究了不同水泥掺和百分比αw时水泥土、桩土界面抗剪强度的变化现律及桩侧摩阻力的变化规律．总结出水泥土的C、值增率ECi和Ei与αw的关系式．桩土界面抗剪强度增率Mi与αw的关系式，桩侧摩阻力增率EMi与αw的关系式．指出实际工作时．可采用桩土界面抗剪强度增率Mi来计算桩侧摩阻力增量及桩的承载力．工程实例进一步证明，采用这种定量方法是安全可靠的．

Based on the analysis of the achievements by fore faters, the paper has studied the quantitative calculation method of friction piles rounded by cement soils. It researches laws of that: the shear strength of soilschanges with the percentage of cements injected into soils; the shear strength changes as the percenage of cements on the boundary face btween pilas and soils; and the frictional resistance of cements soils varies as thepercentage of cements injected into soils. Based on the researches. the paper puts forward the method of design and the main points of grounding to enhance the performance of piles.The main conclusions are as follows:gi ) It can raise frictional resistance of soils and load bearings of piles to ground soils around piles. Therising rate (M,) of frictional resistance of soils rizes as the percent age of cements (aw). Their relation is: (2)Results of static load test of physical models are the same as those of shear tests on the boundary facebetween piles and cement soils. It means that. the 'Mi-ax' formula can be used in calculating the rising value of frictional resistance.(3)By injecting cement into soils around piles. the shear failure occurs in the boundanry face betweenpiles and cement soils.(4 )Shear strengths of cement soils rise as the percentage of cements injected into soils. The rising rate ofthe cohesive force (ECi) and the rising rate of the angle of friction. are: