深海管线通常铺设于海床表面,在自重和铺管作业的影响下会嵌入海床,其嵌入深度w_(ini)显著影响海床对管线的侧向土阻力。现有研究多聚焦于嵌入深度较浅情况(w_(ini)=0.1D~0.5D,D为管径),而最新调查表明,部分管线嵌入深度已超过0.5D。为...深海管线通常铺设于海床表面,在自重和铺管作业的影响下会嵌入海床,其嵌入深度w_(ini)显著影响海床对管线的侧向土阻力。现有研究多聚焦于嵌入深度较浅情况(w_(ini)=0.1D~0.5D,D为管径),而最新调查表明,部分管线嵌入深度已超过0.5D。为揭示更大嵌入深度下管-土相互作用机制,采用径向基点插值法-网格重剖分和小应变插值技术(radial point interpolation method-remeshing and interpolation technique with small strain,简称RPIM-RITSS)数值方法,对嵌入深度为0.1D~1.0D的管线开展了管-土侧向相互作用大变形数值分析。通过与已有相关离心机试验及数值结果对比,验证了该数值方法的有效性。在此基础上,深入分析了管线嵌入深度和重量对其侧向屈曲模式和土阻力的影响,据此提出了适用于嵌入深度为0.6D~1.0D的残余侧向屈曲土阻力预测模型,以期为深海管线的侧向稳定性和安全评估提供参考。展开更多
Slopes are likely to fail in areas with frequent rainfall and earthquakes.The deformation characteristics of unsaturated slopes subjected to post-rainfall earthquakes are investigated using centrifuge model tests and ...Slopes are likely to fail in areas with frequent rainfall and earthquakes.The deformation characteristics of unsaturated slopes subjected to post-rainfall earthquakes are investigated using centrifuge model tests and finite element analyses.Three tests of the slope deformation under earthquake and post-rainfall earthquakes are first studied using image analysis techniques.Then,based on an elastoplastic constitutive model,numerical simulations are carried out using the finite element method and compared with the centrifuge test results.Finally,a parametric study is performed to clarify the effects of antecedent rainfall on earthquake-induced slope deformation.The results show that slope deformation caused by post-rainfall earthquakes differs from that caused by earthquakes without antecedent rainfall.The seepage flow and soil strength of the slope are affected by previous rainfall conditions,such as intensity and duration,which directly influence the slope deformation caused by the subsequent earthquake.Soil displacement and strain become greater and the slip surface is more noticeable during the post-rainfall earthquake of higher intensity.In addition,the time interval between the rainfall and the earthquake has a considerable impact on the detailed characteristics of the slope deformation,and the significant deformation occurs at the time of lowest soil strength when seepage flow reaches the lower part of the slope.Moreover,the repeated intermittent rainfall greatly affects the subsequent earthquake-induced slope deformation,the main characteristics of which are closely related to the changes in saturation and strength of the slope.However,with the prolonged time gap between each round of rainfall,the earthquake-induced slope deformation becomes insignificant.展开更多
文摘深海管线通常铺设于海床表面,在自重和铺管作业的影响下会嵌入海床,其嵌入深度w_(ini)显著影响海床对管线的侧向土阻力。现有研究多聚焦于嵌入深度较浅情况(w_(ini)=0.1D~0.5D,D为管径),而最新调查表明,部分管线嵌入深度已超过0.5D。为揭示更大嵌入深度下管-土相互作用机制,采用径向基点插值法-网格重剖分和小应变插值技术(radial point interpolation method-remeshing and interpolation technique with small strain,简称RPIM-RITSS)数值方法,对嵌入深度为0.1D~1.0D的管线开展了管-土侧向相互作用大变形数值分析。通过与已有相关离心机试验及数值结果对比,验证了该数值方法的有效性。在此基础上,深入分析了管线嵌入深度和重量对其侧向屈曲模式和土阻力的影响,据此提出了适用于嵌入深度为0.6D~1.0D的残余侧向屈曲土阻力预测模型,以期为深海管线的侧向稳定性和安全评估提供参考。
基金supported by the China Postdoctoral Science Foundation(CPSF)(Grant No.2024M762769)the Natural Science Basic Research Program of Shaanxi(Grant No.2024JC-YBQN-0333)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20232230).
文摘Slopes are likely to fail in areas with frequent rainfall and earthquakes.The deformation characteristics of unsaturated slopes subjected to post-rainfall earthquakes are investigated using centrifuge model tests and finite element analyses.Three tests of the slope deformation under earthquake and post-rainfall earthquakes are first studied using image analysis techniques.Then,based on an elastoplastic constitutive model,numerical simulations are carried out using the finite element method and compared with the centrifuge test results.Finally,a parametric study is performed to clarify the effects of antecedent rainfall on earthquake-induced slope deformation.The results show that slope deformation caused by post-rainfall earthquakes differs from that caused by earthquakes without antecedent rainfall.The seepage flow and soil strength of the slope are affected by previous rainfall conditions,such as intensity and duration,which directly influence the slope deformation caused by the subsequent earthquake.Soil displacement and strain become greater and the slip surface is more noticeable during the post-rainfall earthquake of higher intensity.In addition,the time interval between the rainfall and the earthquake has a considerable impact on the detailed characteristics of the slope deformation,and the significant deformation occurs at the time of lowest soil strength when seepage flow reaches the lower part of the slope.Moreover,the repeated intermittent rainfall greatly affects the subsequent earthquake-induced slope deformation,the main characteristics of which are closely related to the changes in saturation and strength of the slope.However,with the prolonged time gap between each round of rainfall,the earthquake-induced slope deformation becomes insignificant.
