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
Deformations in high fill foundations comprising soil–stone mixtures must be accurately predicted to ensure construction quality and long-term operational safety.However,existing computational and analytical methods ...Deformations in high fill foundations comprising soil–stone mixtures must be accurately predicted to ensure construction quality and long-term operational safety.However,existing computational and analytical methods inadequately capture their complex mechanical behavior.We conducted a series of triaxial tests on unsaturated soil samples collected from a high fill project site in northwestern China under three stress paths.The incremental nonlinear and elastoplastic constitutive models for unsaturated soils were modified,and a calculation method was developed for the vertical and lateral deformations of high fill foundations using the layered summation approach.The results indicate that for soil samples with the same mixing ratio(m)and compaction coefficient(n),the strength of the sample and its tendency to exhibit shear dilation increase with the net confining pressure or matric suction.Additionally,the stress–strain curve of the soil sample gradually changes from the strain-hardening type to the ideal elastoplastic type as the compaction coefficient increases.Moreover,the compaction coefficient is an important factor influencing the magnitude of yield stress and yield suction in soil samples,and the yield points of both are similar in shape to the loadingcollapse(LC)and suction increase(SI)yield lines obtained using the Barcelona model in the net mean stress-generalized shear stress(p-s)plane,respectively.The modified incremental nonlinear instantaneous model simultaneously considers the effects of the compaction coefficient,suction and mixing ratio,and the model parameter can be simplified to the tangential modulus expression in the Duncan-Chang model when the suction is zero.Furthermore,the modified elastoplastic constitutive model,which considers the effects of the net mean stress,suction and partial stress,can be simplified to the elastoplastic constitutive relationship of saturated soil when the suction is zero.The proposed deformation calculation method,based on the layered summation theory,is applicable to both elastic and elastoplastic foundation states,as confirmed through numerical simulations.Our work can be used as a reference for the calculation of foundation deformation in similar mixed material high fill projects.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funded by the National Natural Science Foundation of China(Grant Nos.52368049,52168051,and 42462028)Lanzhou Young Scientific and Technological Talents Innovation Project(Grant Nos.2023-QN-27 and 2023-QN-52)Major Project of the Joint Scientific Research Fund of Gansu Province(Grant No.25JRRL007)。
文摘Deformations in high fill foundations comprising soil–stone mixtures must be accurately predicted to ensure construction quality and long-term operational safety.However,existing computational and analytical methods inadequately capture their complex mechanical behavior.We conducted a series of triaxial tests on unsaturated soil samples collected from a high fill project site in northwestern China under three stress paths.The incremental nonlinear and elastoplastic constitutive models for unsaturated soils were modified,and a calculation method was developed for the vertical and lateral deformations of high fill foundations using the layered summation approach.The results indicate that for soil samples with the same mixing ratio(m)and compaction coefficient(n),the strength of the sample and its tendency to exhibit shear dilation increase with the net confining pressure or matric suction.Additionally,the stress–strain curve of the soil sample gradually changes from the strain-hardening type to the ideal elastoplastic type as the compaction coefficient increases.Moreover,the compaction coefficient is an important factor influencing the magnitude of yield stress and yield suction in soil samples,and the yield points of both are similar in shape to the loadingcollapse(LC)and suction increase(SI)yield lines obtained using the Barcelona model in the net mean stress-generalized shear stress(p-s)plane,respectively.The modified incremental nonlinear instantaneous model simultaneously considers the effects of the compaction coefficient,suction and mixing ratio,and the model parameter can be simplified to the tangential modulus expression in the Duncan-Chang model when the suction is zero.Furthermore,the modified elastoplastic constitutive model,which considers the effects of the net mean stress,suction and partial stress,can be simplified to the elastoplastic constitutive relationship of saturated soil when the suction is zero.The proposed deformation calculation method,based on the layered summation theory,is applicable to both elastic and elastoplastic foundation states,as confirmed through numerical simulations.Our work can be used as a reference for the calculation of foundation deformation in similar mixed material high fill projects.
