基于埋深效应与宽度效应的高填方涵洞地基承载力计算

为探明上埋式涵洞侧填土荷载对地基承载力的影响,基于普朗特尔-赖斯纳与太沙基极限承载力理论,研究了涵洞基础深度效应与宽度效应下涵洞基底粉质黏土、黏性土与砂土地基承载力变化规律与曲线特征。此外,基于涵洞地基的实际受力情况与涵洞地基承载力计算图示,修正了太沙基地基承载力计算方法,并将用修正方法计算得到的涵底地基承载力结果与数值模拟计算结果、太沙基方法计算结果进行了对比分析。结果表明:(1)涵洞基础深度效应与宽度效应对高填方涵洞地基承载力的提高作用明显,随着基础埋深系数的增加,粉质黏土、黏性土与砂土的地基承载力值随之增加,粉质黏土与黏性土地基增加的幅度较小,砂土地基增加的幅度较为显著;(2)当基础宽度系数k≥5时,黏土与砂土地基承载力增长幅度减小,而粉质黏土地基承载力增长幅度较大;(3)填土高度为6 m时,改进方法计算得到的地基承载力值比有限元法大8.78%,比太沙基计算公式法大18.72%,改进方法比太沙基方法更接近涵洞地基极限承载力值。

The Calculation of Bearing Capacity of High Fill Culvert Foundation Based on Depth Effect and Width Effect

In order to explore the influence of side filling load of upper-buried culvert on the foundation bearing capacity, based on the ultimate bearing capacity theory of Prandtl- Reissner and Terzaghi, studying the variation law and curve characteristics of silty clay, clay and sand foundation bearing capacity under the depth and width effects of culvert foundation. Based on the actual stress condition of culvert foundation, proposing the calculation diagram and improved calculation method of culvert foundation bearing capacity. The results of the improved calculation method are compared with those of the numerical simulation and the Terzaghi method. The results show that: (1) The depth effect and width effect of culvert foundation can improve the bearing capacity of high fill culvert foundation obviously. With the increase of foundation burial depth coefficient, the bearing capacity of silty clay, clay and sandy soil increases.(2) When the foundation width coefficient K is larger than 5, the increase rate of foundation bearing capacity of clay and sand decreases, and the increase rate of foundation bearing capacity of silty clay is larger.(3) The foundation bearing capacity of the improved method is 5.28% larger than that of the finite element method and 15.29% smaller than that of the Terzaghi formula method. The improved method is closer to the true bearing capacity of culvert foundation than the Terzaghi method.