﻿ 深海管道轴向定向移动消减方案研究
 海洋科学  2020, Vol. 44 Issue (9): 112-120 PDF
http://dx.doi.org/10.11759/hykx20190320002

#### 文章信息

LIU Run, HAO Xin-tong, LI Cheng-feng, PENG Bi-yao. 2020.

Study on deep-sea pipeline walking mitigation

Marina Sciences, 44(9): 112-120.
http://dx.doi.org/10.11759/hykx20190320002

### 文章历史

Study on deep-sea pipeline walking mitigation
LIU Run, HAO Xin-tong, LI Cheng-feng, PENG Bi-yao
State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, China
Abstract: To address the axial walking of non-buried deep-sea pipelines under cyclic thermal-loading and internal-pressure conditions, this study, using a numerical method, first demonstrates the influence of the steel catenary riser (SCR) tension on the pipeline walking, which is greater than the influences of other mechanisms. Then, the effects of different walking mitigation methods are presented using a pipeline model connected to the SCR. Results show that axial walking can be effectively restrained using anchor piles. In addition, the anchor force and the effective axial force are smaller when the anchor is installed at the pipeline middle. Sliding foundations can minimize the accumulative stress on the pipeline by allowing free-end movements. The combination of the sliding foundation at the pipeline end and the anchor at the middle can further reduce the anchor force by 54% and the compressive effective axial force by 33%, which will optimize the anchor system and effectively reduce the axial walking.
Key words: subsea pipelines    axial walking    steel catenary riser (SCR) tension    anchor piles    sliding foundation

1 短管轴向移动诱因的敏感性分析

 图 1 敏感性分析模型 Fig. 1 Sensitivity analysis model

SCR张力以管道终端集中力的方式施加, 取SCR底部张力为FSCR=200 kN。PLET端采用非线性弹簧模拟, 力-位移关系曲线见图 2

 图 2 PLET力-位移曲线 Fig. 2 PLET force-displacement response

 图 3 升温曲线 Fig. 3 Heating curve

 图 4 工况a管道有效轴力分布 Fig. 4 Effective axial force profile of case a

 图 5 不同模型管道热端轴向移动量-循环曲线 Fig. 5 Hot end walking vs. cycle of different models

 图 6 SCR张力敏感性分析模型图 Fig. 6 Model for SCR tension sensitivity analysis

 图 7 FSCR=200 kN下管道有效轴力分布 Fig. 7 Effective axial force profile when FSCR = 200 kN

 图 8 不同SCR张力下管道热端轴向移动量-循环曲线 Fig. 8 Hot end walking vs. cycle under different SCR tensions

2 最佳锚固方式的确定 2.1 锚固方案

1) 常见锚链系统组成

 图 9 管道中部锚固示意图 Fig. 9 Anchor at the pipeline midpoint

2) 锚固计算方案

 方案 锚固方案示意图 方案1 PLET单向锚 方案2PLET双向锚 方案3 SCR单向锚 方案4 SCR双向锚 方案5 中部单向锚 方案6 中部双向锚
2.2 不同锚固方案计算结果

6种锚固方案下分别计算了un的关系, 计算结果如图 10所示。

 图 10 6种锚固方案管道轴向移动量-循环曲线 Fig. 10 Walking vs. cycle for six anchor cases a:冷端移动量-循环曲线; b:热端移动量-循环曲线

 图 11 方案1及方案2有效轴力分布 Fig. 11 Effective axial force profile of cases 1 and 2

 图 12 方案1卸载过程中有效轴力变化图 Fig. 12 Effective axial force during the unloading of case 1

 图 13 方案3及方案4有效轴力分布 Fig. 13 Effective axial force profile of cases 3 and 4

 图 14 方案5及方案6管道有效轴力分布 Fig. 14 Effective axial force profile of cases 5 and 6

2.3 推荐的锚固方案

 消减方案 最大移动量/m Fanc, max/kN Feff, max/kN leff/m PLET端 SCR端 PLET端单向锚 0.610 2.151 814 –333 1 476 PLET端双向锚 0 2.710 814 –559 1 476 SCR端单向锚 2.479 0.610 964 –763 2 000 SCR端双向锚 2.479 0 765 –765 2 000 管道中部单向锚 1.304 1.434 278 –457 1 475 管道中部双向锚 1.304 1.434 278 –457 1 475

3 锚固与滑动基础的耦合 3.1 端部锚固耦合滑动基础

 图 15 带滑动基础的PLET示意图 Fig. 15 Sketch of the PLET sliding foundation

 图 16 带滑动基础的管道有效轴力分布 Fig. 16 Effective axial force profile with the sliding foundation

 图 17 带滑动基础的管道两端轴向移动量-循环曲线 Fig. 17 Walking vs. cycle with the sliding foundation

3.2 中部锚固耦合滑动基础

 图 18 管道两端轴向移动量-循环曲线 Fig. 18 Walking vs. cycle

 图 19 管道有效轴力分布对比 Fig. 19 Comparison of the effective axial force

4 结论

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