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锚杆锚固段界面剪应力分布规律是锚杆设计研究的重点,直接影响锚固效果。锚固段界面上的剪应力会引起界面附近的岩土体较大的应变梯度,而用经典弹性理论分析锚固段剪应力时没有考虑应变梯度。偶应力理论引进弯曲曲率,考虑弯曲效应对介质变形特性的影响,基于该理论建立平面应变问题的有限元计算模型,研究拉力型锚杆锚固段界面上的剪应力分布、界面附近的边界层效应和偶应力的尺度效应,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比较。结果表明,在偶应力理论下,拉力型锚杆锚固段界面的剪应力和剪应变有所减小,特别是峰值处的剪应力减少明显;界面处的剪应力不再连续;界面附近的剪应变突变有所改善,出现一个过渡区域。特征长度减小,过渡区域变小,应变梯度增大,第二剪切模量对剪应力分布的影响不明显。
The distribution of shear stress at the anchorage section of anchor is the key point in the research of anchor design and directly affects the anchoring effect. Shear stress at the interface of the anchorage section leads to larger strain gradient of the soil near the interface, while the strain gradient is not taken into account when using the classical elastic theory to analyze the shear stress in the anchorage section. The theory of even-stress introduces the curvature of curvature and considers the influence of bending effect on the deformation of the medium. Based on this theory, a finite element model of plane strain problem is established to study the distribution of shear stress at the interface of tension-type anchor. And even-stress scale effects, and the results of even-stress theory and classical elasticity theory are compared. The results show that under the dual stress theory, the shear stress and the shear strain at the interface of the anchorage section of the tensioned anchor are reduced, especially the shear stress at the peak decreases obviously; the shear stress at the interface is no longer continuous; the shear near the interface Strain mutations improved, showing a transitional region. The feature length decreases, the transition region becomes smaller, the strain gradient increases, and the effect of the second shear modulus on the shear stress distribution is not obvious.