新疆地区750 kV线路工程冻胀地基基础上拔力计算探讨

Study on Uplift Force Calculation on Frost Heave Foundation of 750 kV Line Project in Xinjiang Region

冻土地区因冻胀作用产生的上拔力对架空输电线路基础的设计影响很大,做好冻土地区因冻胀作用产生的上拔力的计算十分重要。通过分析阿勒泰750 kV线路工程区域气象资料,发现其寒季冻结期10 m高50 a一遇风速约为全年统计风速的90%,风压的80%,也就是说冻结期风荷载比规范公式推荐取值大,若按规范取值易造成上拔力计算过小,架空输电线路基础设计不安全。为确保架空输电线路基础的安全性,结合规范中寒季冻结期基础上拔力设计值估算公式对本工程基础上拔力进行修正,取得了好的效果,可以为同类地区线路工程提供参考。

The uplift force caused by frost heave in frozen soil area has great influence on the design of the foundation of overhead transmission line.It is very important to calculate the uplift force caused by frost heave in frozen soil area.Based on an analysis of the regional meteorological data of the Altay 750 kV line project,it is found that the 10-meter-high wind speed in the freezing period of the cold season which occurs about once in 50 years accounts for about 90%of the annual statistical wind speed and about 80%of the wind pressure,that is to say,the wind load in freezing period is larger than the value recommended by the standard formula.If the value is calculated according to the standard,the calculation of the uplift force will tend to be too small and the design of overhead transmission line foundation is not safe.In order to ensure the safety of overhead transmission line foundation,the foundation uplift force of this project is modified based on the foundation uplift force design value estimation formula of the freezing period in the standard middle cold season,and good results have been achieved,which can provide reference for line projects in similar areas.