【摘要】 深海管道在自身重量、水压以及铺设的作用下会嵌入到海床的一定深度处,其中管土垂向相互作用会对管道在海底的在位稳性造成影响,选择合适的数值计算方法来处理地基土壤网格有重要意义.文中基于Lagrangian、ALE、CEL法开展了管土相互作用的数值模拟对比分析,得到管道下沉位移—抗力载荷关系曲线,与现有理论研究成果进行了对比.研究了网格尺寸大小、管道贯入速度及管道与土壤接触表面的不同粗糙度等因素对管土相互作用模拟方法的影响,通过ALE、CEL法对无量纲化参数E_u/S_u、土壤容重γ′进行了参数敏感性分析.分析结果表明:ALE、CEL法均较Lagrangian法具有更高的准确性.其中ALE法更适合接触面粗糙的情况,CEL法更适合接触面光滑的情况,并且判断出网格尺寸敏感性和贯入速度影响程度的临界点通常出现在10%～20%管径深处;当E_u/S_u的取值在400～1 000,参数对荷载位移关系几乎没有影响;当管道的贯入深度为10%管径,是判断土壤容重参数敏感性的临界位移.更多还原

【Abstract】 Deep sea pipelines will be embedded into the seabed under the effect of self-gravity, water pressure and laying. In this case, the vertical pipe-soil interaction would have an influence on the stability of the pipeline at the bottom of the sea. It is important to choose a proper numerical method for the simulation. Three different grid algorithms of soil are implemented to investigate the vertical pipe-soil interaction in numerical simulation. The relationship of load and displacement in the process of pipeline sinking can be obtained and compared with the existing theoretical solution. In order to simulate the interaction between the pipe and soil more accurately, the effects of the soil’s grid size, pipeline penetration rate and the roughness of the contact surface between pipe and soil on the simulation results of ALE and CEL are studied in details. Then, the parameter sensitivity analysis was carried out for E_u/S_u and soil bulk density by using ALE method and CEL method. The results show that the methods of ALE and CEL have higher accuracy than Lagrangian method. The ALE method is more suitable for the rough contact surface, and the CEL method is more suitable for the smooth contact surface. Moreover, the critical points of grid size sensitivity and penetration rate influence are usually located at 0.1～0.2 times of the pipe′s diameter. When the value of E_u/S_u is in the range between 400 and 1000, the parameters have little effect on the load-displacement relationship. The critical displacement to judge the sensitivity of the soil bulk density parameter is that the penetration depth of the pipe is 0.1 times the pipe diameter.更多还原