An improved method of pile foundation settlement calculation based on Mindlin-Geddes solution
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摘要: 目前桩基沉降计算多采用Mindlin-Geddes应力解法,为达到精度要求,需对地层进行细致划分,导致该方法计算过程繁琐、效率低下。为提升桩基沉降计算效率,通过解析桩端及桩侧阻力引起的附加应力场,结合Mindlin-Geddes应力解与分层总和法,推导了平均竖向应力影响系数的积分表达式,并改进了桩基沉降计算公式。同时,编制出不同阻力分布模式下的平均竖向应力影响系数的计算表格。无量纲应力面积算例和工程案例分析计算表明,平均竖向应力影响系数方法与规范方法计算结果吻合,精度满足要求,且不需要对每层土再进行细分计算,有效提升了桩基沉降计算效率与精度,为桩基工程设计提供了新的计算方法与技术手段。
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关键词:
- Mindlin-Geddes应力解 /
- 平均竖向应力影响系数 /
- 积分表达式 /
- 阻力分布模式
Abstract: Currently, the calculation of pile foundation settlement mostly relies on the Mindlin-Geddes stress solution. To meet accuracy requirements, this method demands a detailed subdivision of soil strata, resulting in a cumbersome and inefficient computational process. To improve computational efficiency, by combining the Mindlin-Geddes stress solution with the layered summation method, the integral expressions of the average vertical stress influence coefficient were derived, and the pile foundation settlement calculation formulas were improved. Meanwhile, calculation tables of the average vertical stress influence coefficients under different resistance distribution patterns were compiled. Through the calculation and analysis of a dimensionless stress area example and an engineering case, the results show that the average vertical stress influence coefficient method agrees well with the calculation results of the standard method, the accuracy meets the requirements. Moreover, it does not need to further subdivide each soil layer for calculation, effectively improves the efficiency and accuracy of pile foundation settlement calculation, and provides new calculation methods and technical means for the design of pile foundation projects. -
表 1 岩土体计算参数
Table 1. Calculation parameters of rock and soil mass
岩土编号 岩土名称 重度/(kN∙m−3) 压缩模量/MPa ⑨ 圆砾、卵石 20.20 40.00 ⑨1 细中砂 20.20 32.00 ⑩ 黏土 18.86 14.25 ⑩1 粉质黏土、重粉质黏土 19.75 15.63 ⑩3 黏质粉土、砂质粉土 20.40 23.80 ⑪ 细中砂 20.50 35.00 ⑫ 粉质黏土、重粉质黏土 20.13 16.12 ⑫3 黏土 19.16 15.79 ⑬ 粉细砂 20.80 40.00 表 2 本文方法与规范方法计算结果对比
Table 2. Comparison of calculation results between the method in this paper and the specification method
布桩方式 本文方法
(平均竖向应力影响系数法)规范方法
(竖向应力影响系数法)桩沉降sp/mm 总沉降s/mm 桩沉降sp/mm 总沉降s/mm 方式一 48.9 52.1 49.4 52.6 方式二 37.0 39.7 37.3 39.9 -
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