大口径输油管道水平弯头热弯矩计算方法

目前对于大口径长距离输油管道弯头热弯矩计算还不完善,设计时热弯矩偏小,部分管道弯头在投产后胀裂。为了避免弯头发生胀裂,施工时在每个水平弯头两侧各安装锚固墩保护弯头。这样不仅增加施工时间,也增加了施工的难度和范围。通过理论分析并结合中俄原油管道中漠大线施工中提出的问题,认为可以通过建立的数学模型计算大口径水平弯头两端无锚固墩时的热弯矩,计算结果与实际情况相符,说明可以通过计算,检验弯头在无锚固状态下的安全程度。根据影响因素分析,认为选择大曲率半径和控制施工时温度可以代替铺设锚固墩保障弯头不被温差胀裂,该分析结果可为控制管道的施工进度、利润、安全性提供理论依据。

Method to Calculate the Thermal Bending Moment of Horizontal Elbow of Large Diameter Oil Pipeline

At present the calculation of the thermal bending moment of large diameter long distance oil pipeline elbow is not perfect.Bursting happens to some pipeline elbows when they are put to use.The anchor block is installed on both sides of every horizontal elbow to protect it so as to avoid bursting in construction.In this way the time and profit are wasted in the process of construction.Meanwhile,the difficulty and scope of construction are increased.Through theoretical analysis and referring to the problems in the construction of the Mohe-Daqing line of the Sino-Russian petroleum pipeline,it is suggested that the mathematic model established can be adopted to calculate the thermal bending moment of large diameter horizontal elbow when there is no anchor block on both of its ends.The calculation result is in agreement with the practical condition,which indicates that the safety of the elbow without anchor block can be tested through calculation.According to the analysis of the influencing factors,it is believed that selection of large curvature radius and control of the temperature in construction can replace the laying of anchor block to prevent the elbow from bursting due to temperature difference,which provides the theoretical basis for the constructing progress,profit and safety of control pipeline.