考虑钢悬链线立管安装的管土非线性相互作用机理研究

Characters)：Steel Catenary Riser(SCR) is an important type of riser which link floating platform and subsea production system, is widely used in deepwater oil and gas development.Under the marine environment and the floating vessel motion, the long-term complex nonlinear interction between riser and soil in touch down zone, is an important factor of SCR shape control. Became the hot spot of various scholars' research. In SCR analysis, the linear elastic model is usually used for the seabed model. This will make the difference with the actual situation. This research will focus on the complex nonlinear pipe-soil interaction in TDP area considering installation, large deformation beam theory will used to simulate SCR, by using physical model test and numerical calculation method, study on the effects of riser velocity on the soil resistance and suction force, consider the change rules of soil characteristics under the cyclic loads, combine with the soil friction and the formation of trench, to establish more realistic prediction model, and provide guidance for the design of SCR installation analysis.

钢悬链线立管（SCR）作为连接浮式平台和水下生产系统的重要立管形式，被广泛应用于深水油气开发项目中。在海洋环境和安装船运动作用下，SCR触地区与海床土壤间复杂的非线性相互作用，是SCR形态控制的重要因素，成为各国学者的研究热点。但在SCR分析中多采用线弹性模型模拟海床作用，这与实际情况存在较大差异。本研究针对SCR安装过程中的管土相互作用问题，采用大变形梁理论模拟SCR，以物理模型试验和数值计算为手段，研究管土循环作用下土壤的特性变化规律，确定立管运动速度对海床土壤阻力和吸附力的影响，建立更符合实际的海床作用预测模型。为SCR安装设计提供有力的依据和指导。

本项目通过理论与实验的方法研究了钢悬链线立管（SCR）触地区与海床土壤间复杂的非线性相互作用特性。并针对海床土壤为软粘土条件下，考虑了SCR安装过程中运动速度因素对管-土相互作用的影响规律。基于对模型实验数据分析和耦合欧拉-拉格朗日（CEL）数值模拟方法，建立了考虑土壤特性、立管嵌入深度及立管运动速度因素的管土相互作用阻力模型和吸附力模型；基于大变形梁理论,建立了考虑非线性管-土相互作用的SCR安装力学模型；基于同伦分析法（HAM），获得了深水SCR安装力学模型的近似解析解。以上研究成果为深水SCR 安装设计提供了理论依据。