超大吨位灌注桩承载力试验及数值模型研究

Research on Bearing Capacity Test and Numerical Model of Super Large Tonnage Bored Pile

滨海地区地质条件较差,采用后注浆工艺可有效提高桩基础的承载能力。对于某工程超大吨位承载能力的后注浆工艺灌注桩,其侧摩阻力小于端阻力,经过多种方案比选,笔者设计了自平衡法与堆载配重平台结合的试验方法。该试验方法能够有效验证超大吨位灌注桩的设计承载能力,通过试验推算得到桩身的极限侧摩阻力。试验结果表明,后注浆工艺对侧摩阻力的提高有显著效果。根据岩土参数及试验结果,采用MohrCoulomb本构模型对桩基承载力进行有限元分析,通过试验结果比对验证选取土层参数,可为后期工程桩设计提供依据。

The geological conditions in coastal areas are poor,so the post grouting technology is used to improve the vertical bearing capacity of pile foundation. For super large tonnage post grouting piles, considering that the side friction resistance is less than the end resistance, after the selection of a variety of schemes, a test method of combining self-balanced method with surcharge counterweight platform is designed by the author. This test method can effectively verify the design bearing capacity of super large tonnage cast-in-place piles. The ultimate side friction resistance of the pile can also be calculated by the test. The test results show that the post-grouting technology has a significant effect on the improvement of side friction resistance. According to the geotechnical parameters and test results, the Mohr-Coulomb constitutive model is used to carry out the finite element analysis(FEA) of the bearing capacity of the pile foundation. The soil parameters are specified through the comparison and verification of the test results. The test results and FEA model can provide the basis for the later engineering pile design.