连续沉降过程中管土相互作用规律

1.中国石油大学(华东)储运与建筑工程学院·山东省油气储运安全重点实验室;2.中国石油海洋工程有限公司;3.中国石油天然气股份有限公司

埋地钢管;连续沉降;力学分析;实验研究;数值模拟

Pipe-soil interaction during continuous settlement
LIU Peng1,ZHANG Yu2,LI Yuxing1,FAN Jialin1,WANG Wuchang1,HU Qihui1,HUANG Weihe3

1.College of Pipeline and Civil Engineering, China University of Petroleum (East China)//Shandong Key Laboratory of Oil & Gas Storage and Transportation Safety; 2.CNPC Offshore Engineering Company Limited; 3.PetroChina Company Limited

buried steel pipeline, continuous settlement, mechanical analysis, experimental study, numerical simulation

DOI: 10.6047/j.issn.1000-8241.2024.03.010

备注

【目的】沉降是埋地管道周边常见的地质灾害,严重时可导致管道失效及破坏。研究连续沉降过程中的管土相互作用规律对于保障沉降灾害下埋地管道的安全具有重要意义。【方法】利用自主设计的连续沉降实验系统开展埋地钢管连续沉降实验,探究不同地层土体沉降范围和沉降量下的管土相互作用规律,采用数值模拟方法详细分析了连续沉降过程中的管土相互作用演化过程,并通过非线性多元拟合方法,充分考虑沉降、管道、土体等各项参数,对数值模拟结果进行多元拟合。【结果】随着地层土体沉降量的增加,钢管与周围土体逐渐由协同沉降向非协同沉降演变,管道的力学响应经历了增加、卸载、波动、稳定4个阶段。随着地层土体沉降范围增大,管道与其下方土体完全分离所需的地层沉降量增大。当沉降速度较小时,管道最大应力与沉降量随沉降速度的增加而显著增加;沉降速度超过2×10-5m/s后,管道最大应力与沉降量基本保持不变,但相应的地层沉降量明显增加。此外,拟合得到连续沉降条件下埋地钢管最大VonMises应力预测模型,其计算误差多在10%以内。【结论】不同沉降阶段下的管道力学响应明显不同,并且沉降过程中的地层土体沉降量、沉降范围、沉降速度变化对于管道的力学响应也具有重要影响。此外,研究得到的连续沉降下埋地钢管最大VonMises应力预测模型具有较好的预测效果,能够为连续沉降灾害下的埋地管道安全提供重要判定依据。(图 19表4,参[24]
[Objective] Settlement is a common geological hazard encountered around buried pipelines. Such hazards have the potential to cause pipeline failure and damage, particularly in severe cases. Hence, studying pipe-soil interactions during continuous settlement is crucial to ensure the safety of buried pipelines facing settlement hazards. [Methods] This study explored the law governing pipe-soil interactions within different stratum settlement ranges and amounts, by conducting a continuous settlement experiment on a buried steel pipeline, using a specifically designed experimental system. The evolution process of pipe-soil interactions in the continuous settlement process was meticulously analyzed through numerical simulation. Furthermore, the numerical simulation results were subjected to a multivariate nonlinear fitting process, taking into account various parameters such as settlement, pipeline characteristics, and soil properties. [Results] As the stratum settlement increased, the steel pipeline and surrounding soil progressed from simultaneous settlement to separate settlement. The pipeline exhibited mechanical response in four stages: increase, unloading, fluctuation, and stabilization. As the stratum settlement range expanded, a greater amount of settlement took place before the pipeline was fully separated from the soil beneath it. With low settlement rates, the pipeline experienced significant increases in both maximum stress and settlement as the settlement rate grew. However, once the settlement rate surpassed 2×10-5 m/s, the maximum stress and settlement of the pipeline remained nearly unchanged, while the corresponding stratum settlement exhibited notable increases. Moreover, the fitting process yielded a maximum Von Mises stress prediction model for buried steel pipelines exposed to continuous settlement, achieving a calculation error dominantly within 10%. [Conclusion] The mechanical response of pipelines exhibits distinct variations across different settlement stages. Furthermore, any alterations in stratum settlement, settlement range, and settlement rate during the settlement process significantly influence the mechanical response of pipelines. In addition, the prediction model for the maximum Von Mises stress in buried steel pipelines exposed to continuous settlement is demonstrated effective. This model serves as a crucial basis for assessing the safety of buried pipelines under continuous settlement-induced disasters. (19 Figures, 4 Tables, 24 References)
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