直埋压制三通疲劳极限合理性对比分析

Contrastive Analysis on Rationality of Fatigue Limit in Directly Buried Extruded Tees of Specification

通过对供热直埋管网事故近300份调查问卷的统计发现,在约30年的运行过程中,DN500及以下的预制保温直埋供热管道,由于三通破坏而引起供热事故的概率仅占5.55%,远远低于其他构件。通过对DN500及以下的小管径压制三通进行数值模拟,分析了压制三通在有无披肩加强情况下应力大小及应力分布规律。发现实际运行的三通最大当量应力值已超过现有规范规定的疲劳极限,但是仍能安全运行,所以应探究更加合理的疲劳极限。

According to the statistics of 300 questionnaires on the accidents of directly buried heating pipe network,in the operation process lasting for about 30 years,the accident probability of prefabricated directly buried insulating pipe of DN500 and below caused by tees destruction accounted for only 5.55%,far less than other valves and accessories.With numerical simulation made on extruded tees joint with small pipe diameter DN500 and below,the stress intensity and stress distribution law of extruded tees joint under the condition with/without cape strengthening was analyzed.The obtained results show that the maximum equivalent stress of the joint in actual operation has exceeded the fatigue limit specified by the existing specification,but it still operate safely;rational fatigue limit shall be explored.