滑坡碎屑流纵向作用下埋地管道变形分布预测

Prediction of deformation distribution of buried pipeline under longitudinal action of landslide debris flow

摘要:

为保证滑坡碎屑流作用下埋地燃气管道安全运行，基于热-弹塑性理论，采用管-土耦合方法建立了管-土变形分析模型，模拟分析了埋地天然气管道的轴向应变分布规律。基于埋地天然气管道应变分布特征，通过非线性拟合方法，确定了管道轴向应变分布预测模型。研究结果表明: 滑坡碎屑流作用下土壤变形区域主要为碎屑流作用区及其附近区域，滑坡碎屑流前部区域土壤变形明显大于后部区域；管道主要为弯曲变形，管土之间变形并不同步，土壤变形明显大于管道变形；在各个路径上，管道既存在拉应变，又存在压应变，而滑坡碎屑流作用区域，在管道底部和顶部路径上分别取得轴向拉压应变极值；碎屑流宽度、厚度对管道应变分布范围影响有限，应变分布范围随着碎屑流长度增加显著扩张，其中碎屑流影响区域范围是碎屑流作用区长度的3倍左右；而管道应变分布预测模型仅与μ、σ、a₁参数相关，仅需3个位置的轴向拉压应变数据，即可确定该区域管段轴向拉压应变分布。上述研究成果将为管道滑坡灾害下管道应变分布的确定提供重要理论依据。

Abstract:

For the safe operation of buried gas pipeline under the action of landslide debris flow, a pipe-soil deformation analysis model was established based on the thermo-elastic-plastic theory and the pipe-soil coupling method. The axial strain distribution of buried gas pipeline was simulated and analyzed. On the basis of the strain distribution characteristics of buried natural gas pipeline, the prediction model of axial strain distribution of pipeline was determined by nonlinear fitting method. Results show that the soil deformation area under the action of landslide debris flow was mainly the area of debris flow and its vicinity, and the soil deformation in the front area of landslide debris flow was significantly greater than that in the rear area. The main deformation of the pipeline was bending, the deformation between the pipe and the soil was not synchronous, and the deformation of the soil was obviously greater than that of the pipeline. In each path, the pipeline was under both tensile strain and compressive strain. In the area of landslide debris flow action, the extreme values of axial tensile strain were obtained from the bottom and top paths of the pipeline respectively. The breadth and thickness of the debris flow had limited influence on the strain distribution range of the pipeline, and the strain distribution range significantly expanded with the increase in the length of the debris flow, in which the area affected by the debris flow was about 3 times the length of the debris flow action zone. The strain distribution prediction model was related to three parameters of μ, σ, a₁. The data of axial tension and compressive strain of only three positions were needed to determine the axial tension and compression strain distribution of the pipe segment in the region. The research results will provide important theoretical basis for the determination of pipeline strain distribution under pipeline landslide disaster.