基于滑面正应力修正的浅埋矩形基础地基承载力计算  

THREE-DIMENSIONAL BEARING CAPACITY OF RECTANGULAR FOOTING BASED ON MODIFICATION OF NORMAL STRESSES OVER SLIP SURFACE

作　　者：沈银斌[1,2] 朱大勇[2,3] 卢坤林[2,3] 

机构地区：[1]合肥工业大学建筑设计研究院,安徽合肥230009 [2]合肥工业大学安徽省土木工程与材料省级重点实验室,安徽合肥230009 [3]合肥工业大学土木与水利工程学院,安徽合肥230009

出　　处：《岩石力学与工程学报》2014年第11期2351-2359,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51078123;51179043)

摘　　要：提出一种能够计算浅埋矩形基础地基承载力的三维分析方法。首先,假设滑动面为一组由沿基础长轴方向的具有不同初始半径的螺旋线构成的三维椭球滑面;然后,对基于滑面正应力修正的三维边坡极限平衡方法进行改进,建立基于滑面正应力修正的计算固定三维滑面极限承载力方法;最后,通过改变螺旋线极点位置,构造所有可能破坏的滑动面,试算不同滑面所对应的极限承载力,搜索出的最小值即为基础极限承载力,其对应的滑面即为破坏滑动面。为使该方法能用传统的叠加法公式进行地基承载力计算,给出三维条件下的各地基承载力系数值,并研究基础长宽比和土的内摩擦角对各系数的影响。用该方法和给出的三维地基承载力系数分别对算例进行计算分析,并和其他方法进行比较,结果表明该方法合理可靠,能够方便、快速计算矩形基础地基承载力。A new method was proposed for three-dimensional analysis of the bearing capacity of shallow rectangular footing based on the modification of normal stresses over the slip surface. Firstly,the shape of the slip surface was assumed as an ellipsoid composed of a set of log-spirals with different initial radii in the direction of the longer axis of the footing base. Secondly,a method for calculating the bearing capacity of a fixed three-dimensional slip surface was established based on the modification of normal stresses over the slip surface to improve the limit equilibrium solution of 3D slope stability. Finally,the bearing capacities were obtained for the footing with selected fixed three-dimensional slip surfaces resulted from changing the positions of the pole of log-spirals so that the minimum bearing capacity was determined. The bearing capacity coefficients were then given for calculating the bearing capacity with the method of superposition in the conventional bearing capacity formula. The effects of the angle of internal friction and the length-width ratio of footing were investigated. An example was presented to calculate the bearing capacity and the calculated results were compared with those from other methods. The results demonstrate its accuracy,reasonability and high effectiveness in the three-dimensional bearing capacity analysis of rectangular shallow footing.

关 键 词：土力学 承载力 极限平衡 浅埋矩形基础 滑动面 正应力 

分 类 号：TU443[建筑科学—岩土工程]