横缝对地下厂房岩锚吊车梁承载力的影响研究

摘要

The problem of horizontal cracks in rock-bolted crane girders in underground powerhouse of a hydropower station was very prominent with a lot of penetrating cracks even in construction period,posing safety risks on the long-term stable operation.According to the design and construction condition,the bearing behaviors of the girders with different horizontal cracks distribution were studied by numerical approach and the deformation and forces of crane girder were analyzed.Results show that the horizontal cracks could reduce the local stiffness of girders and increase the deformation.Tensile stress concentrated near the crack tip,and the distribution of tensile stress widened,with some exceeding the allowable range.Nevertheless,the horizontal crack has little effect on the safety factor of the anti-sliding stability.Since the rock-bolted crane girders must be in long-term safety,reinforcement in the horizontal crack concentrated area is needed.%某水电站地下厂房岩锚吊车梁横向裂缝问题十分突出,施工期已经产生了大量贯穿性裂缝,对其长期稳定运行存在安全隐患.根据地下厂房岩锚吊车梁设计施工实际情况,采用数值计算方法系统研究梁体在不同横向裂缝分布密度下的承载特性,分析吊车梁的变形以及受力特征.研究结果表明:横向裂缝的存在会导致梁体局部刚度降低、变形增大,在裂缝尖端附近存在一定程度的拉应力集中,梁体拉应力分布范围扩大,局部已超过容许拉应力值,而横向裂缝对梁体抗滑稳定安全系数影响有限.鉴于岩锚吊车梁需长期安全运行,对横向裂缝分布集中部位需进行加固处理.