土拱应力传递模型及其形态差异性对比

Stress Transfer Models of Soil Arching and Their Differences of Patterns

为研究土拱效应的演化过程以及土拱应力的传递规律,根据桩土静力平衡条件及抗剪强度准则建立土拱应力传递模型,并基于工程背景建立数值模型,通过控制等应力差方法比较三种应力云图中土拱的形态差异,并根据土拱应力传递模型对桩后荷载的传递规律进行分析。解析解表明:桩间竖向土拱和桩后水平土拱的法向应力均呈指数递减规律;不同应力云图中土拱形态不同,根据土拱效应随深度的演化过程,可分成四个区域进行研究;水平土拱效应随深度逐渐减弱,桩侧土拱及桩脚处应力随深度均增大并逐渐接近桩后应力;桩后土拱荷载传递系数随深度逐渐减小,桩侧土拱荷载传递系数随深度逐渐增大。

To study evolution processes of the soil arching effect and the stress transfer law of soil arching,according to equilibrium conditions of piles and soil and the shear strength criterion,a stress transfer model of soil arching was constructed.The numerical model was built based on the engineering background,and the pattern differences of soil arching in the three stress contours were compared by controlling the equal stress difference method,besides,in conformity to the stress transfer model of soil arching,the transfer law of loads behind piles was analyzed.The analytical solution showed that the normal stress of vertical soil arching between piles and horizontal soil arching behind piles decayed in the law of the exponential function.According to the evolution process of soil arching effect with depth,it could be divided into four zones to be analyzed.The horizontal soil arching effect decayed with depth,and the stress in the soil arching and pile tip increased with depth and was gradually an approximation to the stress behind piles.The load transfer coefficients of soil arching behind piles decreased with depth,and the load transfer coefficients of soil arching between piles increased with depth.