压力分散型预应力锚杆的力学机理研究

Mechanical behaviors of pressure-dispersive prestressed anchor

通过对压力分散型预应力锚杆锚固段的受力分析,推导出了该类型锚杆的剪应力和轴力分布的解析解。在此基础上,对比了压力分散型锚杆与压力集中型锚杆的受力性能,结果表明,压力分散型锚杆的剪应力和轴力都大幅下降,避免了应力集中。讨论了岩土体的力学参数和预应力对剪应力和轴力的影响,结果表明,岩土体弹性模量和内摩擦角越大,则剪应力峰值越高,轴力衰减越快,且剪应力和轴力分布越集中;预应力越大,则剪应力和轴力越大;黏聚力越大,则剪应力有所增大而轴力有所减小,但影响不大。

Through the mechanical analysis of the anchorage segment of the pressure-dispersive prestressed anchor,the analytic solutions for the distribution of the shear stress and the axial force in the anchor are derived.Based on the developed analytical solutions,the stressed properties of the pressure-dispersive prestressed anchor and the pressure-concentrative prestressed anchor are compared.The results show that the shear stress and axial force of the pressure-dispersive prestressed anchor greatly decrease,and the phenomenon of stress-concentration is avoided.The influences of the mechanical characteristics of the rock mass and the prestress on the shear stress and axial force are discussed.It is shown that the greater the elastic modulus and internal friction angle of rock mass,the greater the maximum of shear stress and the faster the decrease of axial force;the greater the prestress,the greater the shear stress and axial force;and the greater the cohesion,the greater the shear stress and the smaller the axial force,but there is little effect.