基于小波函数的锚杆拉拔全过程分析

Analysis of whole process of bolt pulling based on wavelet function

基于小波函数伸缩平移的特性,建立了能反映锚杆界面黏结-软化-滑动力学特性的剪应力-位移非线性本构模型,克服了三折线软化界面模型需要分段分析的复杂性。结合锚固体荷载传递的力学微分方程,推导了锚杆拉拔荷载-位移曲线的解析表达式,并提出了锚固体位移、轴力、周边剪应力的数值计算方法和步骤。通过算例分析,得到不同张拉位移作用下的锚固段位移、轴力和剪应力分布,获得的锚杆拉拔荷载-位移和锚杆轴向力分布计算值与实测值进行了对比分析,验证了该方法的有效性。该方法能准确地反映锚杆在不同荷载下的传力机制,模拟锚杆从弹性工作状态到塑性滑移的全过程。最后,通过参数分析,得到了锚杆锚固长度、轴向刚度以及锚固界面本构参数对锚固效果的影响规律。

Based on scaling and translation properties of wavelet function, a nonlinear constitutive model of shear stress-displacement of bolt interface is established to simulate the anchoring interface stick-soft-slip mechanical characteristics. The proposed model overcomes the disadvantage in complexity of stage analysis by tri-linear bond-slip model. The equations of load-displacement curves of the bolt is deduced based on the mechanical differential equations of load transfer of the bolt, and corresponding numerical calculation methods and steps are proposed. The displacement, axial force and shear stress distribution along the anchorage length under different pullout displacements are obtained, and the complete load-displacement curve is obtained through a practical example. The calculated load-displacement curves as well as the distributions of the interfacial shear stress and the bolt axial stress are in good agreement with test results. The method can accurately reflect the force transmission mechanism of the bolt under different loads, and simulate the whole process from elastic working state to the plastic slip of the bolt. The influence of the anchorage length, axial stiffness and the constitutive parameters of the anchorage on the anchorage effect are obtained through the analysis of parameters.