无黏性土斜坡地基承载力模型试验研究

Model tests on bearing capacity of footing on sand slopes

采用缩尺模型试验对砂土斜坡地基的土压力分布、变形机制、破坏模式进行探索,并研究了斜坡坡角、基础尺寸、相对密度、基础形状对斜坡地基破坏形态及极限承载力的影响。结果表明:斜坡地基的破坏模式与Choudhury提出的破坏模式相近,破坏区域由不对称楔体、辐射向剪切区、被动楔体组成。斜坡地基的破坏区域长度随斜坡坡角、基础尺寸的增大而增大,但不随相对密度的变化而变化;而斜坡地基的极限承载力随斜坡坡角的增大而减小,随基础宽度、相对密度的增大而增大。对相同尺寸的基础而言,方形基础下的地基极限承载力和破坏区域长度均大于圆形基础。试验研究成果对斜坡地基变形特征、破坏形态和斜坡地基承载力影响因素的探究具有一定理论参考价值。

The earth pressure distribution, deformation mechanism and failure mechanism of the foundation on a sand slope are studied by small-scale model tests in the laboratory. The effects of slope angle, footing width, relative density of sand and footing shape on the ultimate bearing capacity and the failure mechanism of footing on the sand slope are investigated. The results show that the slope failure mechanism is similar to Choudhury＇s failure mechanism, in which the failure zones consist of asymmetric wedge zone, radial shear zone and passive wedge zone. The ultimate bearing capacity of footing on the slope decreases by the accretion of angle of the slope inclination and increases by the rising of footing width and relative density of sand. The failure zone length grows with the enlargement of angle of the slope inclination and footing width, and is hardly affected by the relative density of sand. The bearing capacity and failure zone length of square footings are larger than those of circular ones with the same size. Theoretically, the experimental results contribute to the researches on deformation characteristics and failure mechanism as well as the affecting factors for bearing capacity of the footings on slopes.