锚杆与土体界面渐进破坏的解析解

Analytical solution for progressive failure of interface between anchor and soil

利用点荷载,作用于半无限空间的Mindlin位移解,考虑锚杆与土体界面的渐进破坏过程,推导出界面摩阻力的微分方程解析解。编制了相应的计算程序,把计算结果和现场试验值进行比较,结果较为吻合,二者的数据都表明,随着锚头拉力的增加,土-锚杆摩阻力峰值逐渐向锚杆末端转移,而锚杆前端则发生部分范围的滑移。然后,利用所求得的解析解,研究了土体弹性模量、锚杆孔径对锚杆摩阻力分布的影响,可见土体弹性模量越大,则界面上的摩阻力越容易达到峰值,从而产生破坏,而锚杆孔径越大,则界面上的摩阻力上升越慢,可延缓破坏过程。

An analytical solution for shear distribution of anchor under pull load is present by considering the progressive failure of anchor-soil interface,based on Mindlin solution of force at a point in the interior of a semi-infinite solid. Then an analytical program is developed accordingly,and the flow chart of program is also presented. The results of analytical solution and the field measurements all show that peak value of resistance at the anchor-soil interface transfers to the distal end of the bonded length as the applied load increases. Further,the effect of soil elastic modulus and anchor diameter on shear distribution between anchor and soil is studied by using this analytical model. The result shows that greater soil elastic modulus leads to greater peak shear magnitude under the same load while greater anchor diameter leads to smaller peak shear magnitude.