贴壁混凝土板高度对岩锚梁稳定影响

The Influence of the Height of the Concrete Slab on the Stability of the Rock Anchor Beam

以金川水电站为例,利用Midas GTX NX有限元计算软件,计算分析贴壁混凝土高度对岩锚梁锚杆轴力、岩锚梁应力、应变以及贴壁混凝土内力的影响。结果表明,增加贴壁混凝土板高度导致:(1)岩锚梁受拉锚杆、受压锚杆拉应力降低,岩台面附近受拉锚杆拉应力增加;(2)岩锚梁压应力降低,第一主拉应力和纵向正拉应力降低,第二主拉应力、第三主拉应力增加;(3)竖向向上隆起变形以及水平向向上游方向的变形减小,贴壁混凝土板高度的增加使得岩锚梁各处变形更为均匀;(4)贴壁板下端局部区域拉应力急剧增加,最大主拉应力和纵向拉应值大于混凝土抗拉强度标准值,可以通过配置钢筋承担拉应力。

Taking Jinchuan Hydropower Station as an example,Midas GTX NX finite element calculation software is used to calculate and analyze the influence of the height of the wall-attached concrete on the axial force of the rock anchor beam,the stress and strain of the rock anchor beam and the internal force of the wall-attached concrete.The results show that increasing the height of the concrete slab leads to:(1)the tensile stress of the tensile anchor and the compressive anchor of the rock anchor beam decreases,and the tensile stress of the tensile anchor near the rock table increases;(2)The compressive stress of rock anchor beam decreases,the first principal tensile stress and longitudinal tensile stress decrease,the second principal tensile stress and the third principal tensile stress increase.(3)The vertical upward uplift deformation and the horizontal upstream deformation decrease,and the increase of the height of the concrete slab makes the deformation of the rock anchor beam more uniform.The maximum principal tensile stress and longitudinal tensile stress are greater than the standard value of concrete tensile strength,and the tensile stress can be borne by configuring steel bars.