摘 要: 管道回拖是水平定向穿越铺管工程的关键,而管道安全顺利回拖取决于管道在导向孔中的受力情况。轨迹参数是影响管道回拖力和管道力学特性的主要因素,为保证管道安全顺利回拖,首先通过理论分析得到出土弯曲段是管道回拖工程最危险的区域。进而以兰郑长管道穿越工程为原型,基于有限元方法建立了出土弯曲段管道回拖计算模型,通过分析计算得到穿越轨迹出土段弯曲曲率半径为1200d1~1500d2(d1为管道外径),孔/管比范围为1.3~1.5时,管道在回拖过程中最安全。
关键词:水平定向穿越;管道;回拖力;有限元分析
分类号: TU990.3
Analyzing the forces on the pipeline of the pulling process in the horizontal directional crossing project
Haifeng Ma1 Pengxu Xu1 Biwei Fu1 Yanqing Xi2
1(College of Mechanical Engineering, Southwest Petroleum University, Cheng du 610500)
2(Lukeqing Production Plant, Tuha Oilfield of China National Petroleum Corporation, Tuha 838200, China)
Abstract: The pulling process of pipeline is the critical to the success of the Horizontal directional crossing pipe-laying technology. The forces on the pipeline determine the success of the pulling process of pipeline. It is main factors that the trajectory parameters influence on the pull-back force of pipeline and the mechanics characteristics of pipeline. In order to ensure the success of the pulling process of pipeline, firstly, it is obtained that the unearthed bending section is the most dangerous region of the crossing track by the theoretical analysis. And then it is based on the finite element method that the computational model of the pull-back stage of pipeline is built, which refer to the pipeline crossing project of Lan Zheng Long. Through analyzing the computation results, it is obtained that the optimum range of curvature radius is from 1200D to 1500D (D is the pipe outside diameter) and the best range of the ratio of pore diameter and the pipe diameter is from 1.3 to 1.5. The pipeline can be secure pulled back when above conditions are satisfied.
Keywords: Horizontal directional crossing; Pipe; Drag force; Finite element analysis
1 引言
随着水平定向穿越铺管技术在我国长输油气管道工程中的广泛应用,管道安全铺设引起了广泛关注。特别当管道进入钻孔后,在弯曲段管道因运动方向改变产生绞盘力,适应穿越轨迹产生弯曲力,使管道应力和回拖力增大。如果穿越轨迹设计不当,管道可能在穿越弯曲段时,由于回拖载荷增量过大导致管道回拖工程失败,也可能管道应力超过自身的屈服极限而变形,由此造成重大的经济损失。因此分析穿越轨迹弯曲段参数对回拖力增量和管道应力的影响至关重要。
入土弯曲段与出土弯曲段相比更加危险,因为在出土弯曲段管道自身重力为阻力,而在入土弯曲段为动力,因此在曲率半径相同的情况下,管道若能从出土弯曲段安全回拖,即可保证管道安全[1-2]。
水平定向穿越回拖过程中管道的力学分析已有许多研究,例如,郭晓军采用数值模拟方法分析管道的弹性模量、径厚比和轴向拉力对HDPE管道变形损坏的影响,得到孔壁压力非均匀性和大的轴向拉力是管道变形的重要原因[3]。李文勇采用数值模拟方法分析不同穿越曲线下,管道回拖过程中的力学性能,得到穿越轨迹参数的优选值[4]。王祝生、廖珍标等基于工程问题分析了管道回拖过程中变形的原因,得到造成管道变形的原因是管道材料,管道壁厚和硬物挤压等[5-6]。综合前人的研究可知,很少有人模拟管道在导向孔中动态回拖过程的受力情况,因此本文结合兰郑长水平定向穿越工程的施工数据,基于较少假设的基础上,建立了出土段管道回拖计算模型,通过计算分析穿越轨迹参数对管道力学特性的影响,得到了管道应力与出土算穿越轨迹参数的关系以及穿越轨迹参数的优选范围。
作者:马海峰1 徐鹏旭1 付必伟1 席燕卿2