水电水利工程压力钢管灌浆孔应力集中敏感性因素研究

水电水利工程压力钢管开孔灌浆后,需对灌浆孔严密封堵,处理不好会对工程安全运行留下隐患。在总结国内外灌浆孔常用封堵方案基础上,以某水电站地下埋管为例,建立平面有限元模型,分析其灌浆开孔后管壁应力集中现象,研究了补强板厚度及堵头坡口深度对压力钢管灌浆孔应力集中的敏感性。结果表明,应力集中程度随补强板厚度及堵头坡口深度增加递减,堵头坡口深度对其影响更加敏感。对于地下埋管管壁上开灌浆孔的非高强钢,建议灌浆后孔口进行封堵,补强板厚度宜与钢管壁厚相同,并适当增加坡口深度。当钢管壁厚较大时,堵头坡口深度宜不小于钢管壁厚的1/4~1/3。

Research on the Sensitivity Factors of Stress Concentration of Penstock Grouting Holes in Hydropower Project

The grouting holes in the penstock of hydropower project need to be sealed tightly after the completion of grouting,and poor hole sealing will bring hidden dangers to the safe operation of project.On the basis of summarizing the common plugging schemes for grouting holes at home and abroad,a planar finite element model is established by taking an underground penstock of a hydropower station as an example to analyze the stress concentration of the penstock wall after the grouting hole is opened,and the sensitivity of the thickness of reinforcing plate and the depth of plug groove to the stress concentration of penstock grouting hole is studied.The results show that the degree of stress concentration decreases with the increase of the thickness of reinforcing plate and the depth of plug groove,and the depth of plug groove is more sensitive to stress concentration.For non high-strength steel with grouting holes on the wall,it is recommended that the holes should be plugged after grouting,the thickness of reinforcing plate should be the same as the wall thickness of the penstock,and the groove depth should be increased appropriately.When the wall thickness of penstock is larger,the depth of plug groove should not be less than 1/4~1/3 of the wall thickness of penstock.