饱和中密砂地基中浅基础承载力与变形特性模型试验研究

采用土工鼓式离心模型试验技术,针对饱和中密砂地基的荷载-位移关系、地基承载力系数与基础宽度的关系以及基础尺寸效应等问题进行了研究,对离心模型试验结果的分析方法进行了改进。研究结果表明在有基础埋深情况下,当砂土相对密实度增加时,竖向荷载-位移曲线的斜率在V/D=0.15以后的变化趋势比较明显;随着基础宽度的增加,竖向荷载-位移曲线的初始斜率逐渐增加;将确定地基承载力特征值时所采用的V/D设定在0.015~0.05的范围内时,试验得到的承载力系数N_γ与承载力公式的结果比较接近;当基础宽度>2.0 m时,承载力系数的基础尺寸效应随着地基相对密度的增加而逐渐明显。

Model Study on Bearing Capacity and Deformation Characteristics of Shallow Foundations on Saturated Medium Dense Sand

The relationship between load and displacement of saturated medium dense sand foundation, the bearing capacity vs. footing width relation, and the size effect of footing are investigated using centrifugal modeling technology. Meanwhile, suggestions are given on the methods of analyzing centrifugal modeling results. Research results show that: in the case of footings with embedment, the slope of the curves of vertical load vs. settlement has obvious change trend after V/D=0.15 when the relative density of sand increases. As the footing width increases, the initial slope of the curves of vertical load vs. settlement increases accordingly. When V/D of the characteristic value of bearing capacity is chosen within 0.015-0.05, the centrifugal modeling result of the bearing capacity factor N_γ is close to that of the theoretical formula. When the footing width is bigger than 2.0m, the size effect of footing becomes apparent according to the increase of the relative density of sand.