侧填荷载对涵洞地基承载力的影响

Influence of Lateral Fill Load on Foundation Bearing Capacity of Culvert

为了确定涵侧填土对提高高填方涵洞地基承载力的作用,结合基底土体的受力特点进行分析,推导了普朗特尔和普朗特尔-雷斯诺极限承载力公式。根据相似原理设计了不同涵侧填土高度的室内模型试验,模拟粉质粘土地基受荷变形直到破坏的过程,由荷载-沉降曲线测得不同填土高度的极限承载力,并对填土临界高度问题进行了分析;同时对比了按照《公路桥涵地基与基础设计规范》和《建筑地基基础设计规范》以及经验公式计算的值与实测值的误差。结果表明:随着侧填土高度的增加,地基承载力明显提高,但提高速率为非线性,先从18.4%增加到36.83%,然后减小到8.91%;计算临界高度内的地基承载力时,不仅要考虑选取合适的计算公式,还应考虑不同试验方法所提供的计算参数的影响。

Combined with the stress characteristics of the foundation soil,the soil force was analyzed for finding the improved effect of lateral fill on the foundation bearing capacity of high-stacked culvert.The Prandtl and Prandtl-Reissner foundation ultimate bearing capacity formulas were deduced and contrasted to show the improvement mechanism of lateral fill.Based on the similar principle,laboratory model tests with different lateral fill heights were designed to simulate the silt clay foundation deformation in whole loading process.The foundation bearing capacities under different lateral fill heights were measured by the load-settlement curves.Meanwhile,the critical height of embankment fill was analyzed in detail,the errors among the calculated results with Code for Design of Ground Base and Foundation of Highway Bridges and Culverts,Code for Design of Building Foundation,the empirical formula and the measured result were calculated.The results show that the bearing capacity significantly increases with increasing of lateral fill height,but the growth is nonlinear.It firstly increases from 18.4% to 36.83% and then reduces to 8.91%.Not only the selected calculation formula but also the impact of parameters provided by different test methods will be considered to calculate the foundation bearing capacity within the critical height.