“…Greater ovality means the cross-section of PSP becoming flatter, and ovalization of pipe being more serious. 32 As it is shown in Figure 10(c), since the stress concentration mainly occurs in zone 1 and zone 2, which belong to the area between the settlement section and the transition section of PSP. So this area is taken as the research object of ovality.Figure 17.Related dimensions of deformation of cross-section of PSP.…”
A polyethylene pipe reinforced by winding steel wires (PSP) consists of steel wires and high- density Polyethylene (HDPE). Due to its unique structure and combination of material, the PSP possesses excellent mechanical properties, and it has been widely used in many fields as a buried pipe. Foundation settlement is an evitable loading, and strength failure of buried PSP sometimes occurs due to the foundation settlement. In this paper, numerical investigation of failure behavior of buried PSP was conducted. Firstly, groups of uniaxial tensile tests were carried out to acquire the rate-dependent constitutive equation of the HDPE. Secondly, finite element model of PSP embedded in soil subject to foundation settlement was established. Steel wires are represented by truss elements, and HDPE pipes were modeled with solid elements. The steel wires are built in a spiral structure similar to the real steel-wire mesh of PSP. The effect of the nonlinear material property of components were considered in the model, as the tensile curves were input into the model. The PSP was buried in soil, and foundation settlement was applied on a part of the soil’s top surface as the displacement boundary condition. Due to the great ductility of HDPE, the steel wires broke prior to the HDPE, so the maximum stress of steel wires was used as the failure criterion of PSP. Once the maximum stress of steel wires exceeds the ultimate strength, PSP was considered to have failed. Based on this model, the stress distribution along PSP was investigated with various internal pressure and settlement displacement. The combined influence of the internal pressure and foundation settlement on PSP failure behavior was analyzed, and the location where failure most possibly occurred was determined under different loading conditions. Furthermore, the influence of different structural parameters of PSP and soil was discussed.
“…Greater ovality means the cross-section of PSP becoming flatter, and ovalization of pipe being more serious. 32 As it is shown in Figure 10(c), since the stress concentration mainly occurs in zone 1 and zone 2, which belong to the area between the settlement section and the transition section of PSP. So this area is taken as the research object of ovality.Figure 17.Related dimensions of deformation of cross-section of PSP.…”
A polyethylene pipe reinforced by winding steel wires (PSP) consists of steel wires and high- density Polyethylene (HDPE). Due to its unique structure and combination of material, the PSP possesses excellent mechanical properties, and it has been widely used in many fields as a buried pipe. Foundation settlement is an evitable loading, and strength failure of buried PSP sometimes occurs due to the foundation settlement. In this paper, numerical investigation of failure behavior of buried PSP was conducted. Firstly, groups of uniaxial tensile tests were carried out to acquire the rate-dependent constitutive equation of the HDPE. Secondly, finite element model of PSP embedded in soil subject to foundation settlement was established. Steel wires are represented by truss elements, and HDPE pipes were modeled with solid elements. The steel wires are built in a spiral structure similar to the real steel-wire mesh of PSP. The effect of the nonlinear material property of components were considered in the model, as the tensile curves were input into the model. The PSP was buried in soil, and foundation settlement was applied on a part of the soil’s top surface as the displacement boundary condition. Due to the great ductility of HDPE, the steel wires broke prior to the HDPE, so the maximum stress of steel wires was used as the failure criterion of PSP. Once the maximum stress of steel wires exceeds the ultimate strength, PSP was considered to have failed. Based on this model, the stress distribution along PSP was investigated with various internal pressure and settlement displacement. The combined influence of the internal pressure and foundation settlement on PSP failure behavior was analyzed, and the location where failure most possibly occurred was determined under different loading conditions. Furthermore, the influence of different structural parameters of PSP and soil was discussed.
“…The origins of land subsidence can be traced back to ancient times, but its issues have become more apparent and intricate with the advent of modern industrialization and urbanization. Land subsidence can occur due to a variety of factors, such as the extraction of groundwater and minerals, seismic activity, and surface loads (Larson et al, 2001;Kumar et al, 2022;Wu et al, 2020;Yu et al, 2020). Land sinking has been detected in prominent urban areas, such as Beijing and Shanghai (Gu et al, 2014;He et al, 2018), throughout the past few years.…”
Land subsidence has been a significant focus of geoscience studies, and researching the factors contributing to it and predicting future incidents is essential. However, current research requires a systematic and coherent strategy to identify symptoms of land sinking with scientific rigor. This study employs neural networks and SHAP values to forecast land subsidence. We utilized SHAP values as a substitute for the usual random forest (RF) technique to evaluate the attributes of land subsidence. In addition, we employed neural networks to predict the prospective areas where land subsidence may occur in Chongqing and Chengdu in the future, considering a diverse set of conceivable situations. The results indicate that using neural networks for land subsidence prediction improves the model's accuracy by 16% compared to the traditional approach. The performance is enhanced by approximately 22% after optimizing the input characteristics. The feature optimization strategy proposed in this study, which relies on SHAP values, is particularly advantageous for predicting land subsidence. Moreover, the determinants of land sinking, ascertained by data analysis considering intricate topography, correspond with the conclusions of previous research. Utilizing this feature optimization method can improve the selection of input variables for the land subsidence prediction model, increasing accuracy and providing a solid theoretical foundation for preventing urban land subsidence.
“…In recent years, with the rapid development of oil and gas pipelines, more and more oil and gas pipelines cross the ground subsidence area, such as the China-Myanmar pipeline and West-East Gas Pipeline. Oil and gas pipelines are affected by the external load of ground subsidence, resulting in pipeline deformation, suspension, local deformation, or stress concentration, which leads to large displacement, buckling or creep, and even pipeline fracture cand failure, which poses a serious threat to the safe operation of pipelines [2][3][4][5][6][7]. For example, in July 2011, the Qingdao natural gas pipeline was continuously exposed due to ground subsidence, and it lost fulcrum and leaked.…”
Ground collapse is one of the main geological disasters affecting the safe operation of oil and gas pipelines. Studying the stress-strain characteristics of pipe-soil interaction under ground collapse has an important guiding role for the prevention of ground collapse and the safety protection of pipelines. The current results are mostly concentrated in a single theory or the stress of the pipeline itself, which cannot fully consider the pipe-soil interaction. In this paper, ABAQUS is used to establish the finite element geometric model. Considering the pipeline and the surrounding geological environment conditions, the study is carried out from five aspects: the length of the collapse area, the thickness of the cover layer, the buried depth of the pipeline, the diameter of the pipeline, and the thickness of the pipeline. The displacement of the pipeline soil, the deformation of the pipeline, and the characteristics of the pipeline stress are analyzed, and the variation law is determined through the development trend of the pipeline stress and strain. At the same time, by fitting and analyzing the relationship between the span of different subsidence areas, the thickness of the cover layer, the buried depth of the pipeline, the diameter of the pipeline, the thickness of the pipeline, and the maximum deformation of the pipeline, the reference value of the maximum subsidence displacement of the pipeline under the action of ground collapse is proposed. The work has practical application value for pipeline monitoring, early warning, and disaster management.
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