偶应力理论下拉力型锚固体的受力特性

锚固体的受力特征及其影响因素是锚固体设计的重要依据,直接影响锚固效果。传统的经典弹性理论没有考虑应变梯度的影响。偶应力理论引进弯曲曲率,考虑了弯曲效应对介质变形特性的影响。基于偶应力理论,建立了平面应变问题的有限元计算模型,研究锚固体锚固段界面上的剪应力分布、锚固体轴力分布、偶应力的尺度效应以及弹性模量和围压对锚固力的影响,并将偶应力理论的计算结果和经典弹性理论的计算结果进行了比较。结果表明,在偶应力理论下,锚固体锚固段界面的剪应力有所减小,特别是峰值处的剪应力减小明显;岩土的弹性模量越大,锚固界面局部剪应力越大;锚固力随着围压的增大而增大,偶应力尺度效应明显。

Stress characteristics of tensile-type anchor based on couple stress theory

The stress characteristics and influencing factors of anchor are the important basis of design.It directly affects on anchoring effect.The traditional continuum theory does not consider the influence of strain gradient.Bend curvature was introduced into couple stress which considers the effect on the deformation characteristics of the bending.The finite element calculation model for plane strain problem was built up based on couple stress theory.For tensile-type anchor,shear stress in anchorage interface and the axial force distribution along the anchor and couple stress scale effect were studied.The influence of confining pressure and elasticity modulus on anchorage force was analyzed.The results of couple stress theory are compared with that of typical elasticity theory.The results show that the shear stress near anchorage interface in couple stress theory is smaller than that in traditional theory,especially at the peak of shear stress.The shear stress of interface is enhancing with the increase of the elastic modulus of the geotechnical.The anchorage force enhances with the increase of confining pressure.The couple stress scale effect is obvious.