Lined pipe has been widely used in gathering pipelines systems in highly corrosive gas fields because of its good economy and corrosion resistance. In this harsh environment, the accuracy of pipeline thermal expansion and stress analysis become extremely important. Specific practice for calculating the strength of lined composite pipe was not given in the pipeline stress analysis standards. The general method is to simplify lined pipe to consider only the outer pipe, while ignoring the pressure-bearing effect of the liner pipe. In this method, Outer pipe parameter is only checked as a design parameter in the calculation, which will easily lead to inaccurate result and increase construction cost. Therefore, an equivalent model of lined composite pipe is established in this paper. The geometric parameters and material characteristics such as outer diameter, wall thickness, elastic modulus, thermal expansion coefficient and density, are transformed into equivalent single-layer pipe. The calculation accuracy of this equivalent model has been discussed by theoretical solution and finite element solution. Finally, the equivalent pipe parameters are introduced into the software CAESARII to conduct forces analysis of a gas field lined composite pipe project in the South China Sea. The results show that equivalent pipe model is a simple and reliable stress analysis method for lined pipeline, and its calculation is also convenient and accurate in this paper, which provide a new idea for thermal expansion and stress analysis of lined composite pipeline.

衬里管具有良好的经济性和耐腐蚀性，已被广泛用于高腐蚀性气田的集输管道系统中。在这种恶劣的环境中，管道热膨胀和应力分析的准确性变得极为重要。管道应力分析标准中没有给出计算内衬复合管强度的具体实践。通常的方法是简化衬管，只考虑外管，而忽略衬管的承压效果。这种方法在计算中只检查外管参数作为设计参数，容易导致结果不准确，增加了施工成本。因此，本文建立了衬砌复合管的等效模型。将几何参数和材料特性（例如外径，壁厚，弹性模量，热膨胀系数和密度）转换为等效的单层管道。通过理论解和有限元解讨论了该等效模型的计算精度。最后，将等效管道参数引入软件CAESARII中，以进行南海气田衬砌复合管道项目的受力分析。结果表明，等效管道模型是衬砌管道应力分析的一种简单可靠的方法，计算简便，准确，为衬砌复合管道的热膨胀和应力分析提供了新思路。将热膨胀系数和密度，转化为等效的单层管道。通过理论解和有限元解讨论了该等效模型的计算精度。最后，将等效管道参数引入软件CAESARII中，以进行南海气田衬砌复合管道项目的受力分析。结果表明，等效管道模型是衬砌管道应力分析的一种简单可靠的方法，计算简便，准确，为衬砌复合管道的热膨胀和应力分析提供了新思路。将热膨胀系数和密度，转化为等效的单层管道。通过理论解和有限元解讨论了该等效模型的计算精度。最后，将等效管道参数引入软件CAESARII中，以进行南海气田衬砌复合管道项目的受力分析。结果表明，等效管道模型是衬砌管道应力分析的一种简单可靠的方法，计算简便，准确，为衬砌复合管道的热膨胀和应力分析提供了新思路。将等效的管道参数引入软件CAESARII中，以对南海气田衬砌复合管道项目进行力分析。结果表明，等效管道模型是衬砌管道应力分析的一种简单可靠的方法，计算简便，准确，为衬砌复合管道的热膨胀和应力分析提供了新思路。将等效的管道参数引入软件CAESARII中，以对南海气田衬砌复合管道项目进行力分析。结果表明，等效管道模型是衬砌管道应力分析的一种简单可靠的方法，计算简便，准确，为衬砌复合管道的热膨胀和应力分析提供了新思路。