Computers and Geotechnics最新文献_第10页

Multiscale mechanical behavior of hydrated expansive soil: Insights from experimental and MD study

IF 5.3 1区工程技术

Computers and Geotechnics Pub Date : 2025-02-06 DOI: 10.1016/j.compgeo.2025.107129

Weiwei Niu , Yuan-Yuan Zheng , Zhen-Yu Yin , Chi Yao , Pengchang Wei

{"title":"Multiscale mechanical behavior of hydrated expansive soil: Insights from experimental and MD study","authors":"Weiwei Niu , Yuan-Yuan Zheng , Zhen-Yu Yin , Chi Yao , Pengchang Wei","doi":"10.1016/j.compgeo.2025.107129","DOIUrl":"10.1016/j.compgeo.2025.107129","url":null,"abstract":"<div><div>The mechanical behavior of expansive soil in geotechnical engineering is significantly sensitive to loading rates, hydration, confining pressure, etc., where most engineering problems are attributed to the existence of montmorillonite in expansive soil. Here, the hydration, confining pressure, and loading rate effect on the mechanical behavior of montmorillonite were investigated through the triaxial tests and molecular dynamics (MD) simulation method, revealing their fundamental mechanism between the microscale and macroscale. The average basal spacing of hydrated montmorillonite system, the diffusion coefficient and density distribution of interlayer water molecules were calculated for the verification of MD model. The experimental results indicated that the stress–strain relationship of montmorillonite was the strain-hardening type. The failure stress did not increase monotonously with the increase in loading rate, and there were two obvious critical points. The failure stress of the soil sample increased with the increase of the confining pressure, and the decrease of the water content, where their fundamental mechanism between microscale and macroscale were adequately discussed. Furthermore, the stress–strain response, total energy evolution, deformation evolution of atomistic structure, and broken bonds evolution were analyzed to deeply understand the fundamental deformation mechanism at the microscale. The multi-scale studies could effectively examine the macroscopic mechanical behavior of expansive soil and elucidate its microscopic mechanisms.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"181 ","pages":"Article 107129"},"PeriodicalIF":5.3,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143325092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Comprehensive Investigation of Physics-Informed Learning in Forward and Inverse Analysis of Elastic and Elastoplastic Footing

IF 5.3 1区工程技术

Computers and Geotechnics Pub Date : 2025-02-05 DOI: 10.1016/j.compgeo.2025.107110

Xiao-Xuan Chen , Pin Zhang , Zhen-Yu Yin

{"title":"A Comprehensive Investigation of Physics-Informed Learning in Forward and Inverse Analysis of Elastic and Elastoplastic Footing","authors":"Xiao-Xuan Chen , Pin Zhang , Zhen-Yu Yin","doi":"10.1016/j.compgeo.2025.107110","DOIUrl":"10.1016/j.compgeo.2025.107110","url":null,"abstract":"<div><div>Physics-informed learning has emerged as a promising approach for solving forward and inverse partial differential equations in engineering practice, but selecting an optimal loss function remains unclear and parameter identification for inverse analysis lacks efficiency. Meanwhile, their values for engineering-scale elastoplastic problems have not been deeply investigated. In this research, a comprehensive comparison between the strong-form collocation point method (CPM) and the deep Ritz method (DRM) based loss functions for both forward and inverse analysis is conducted, and a novel exponential acceleration method is proposed to enlarge the search space of unknown parameters for inverse analysis. By applying these methods to linear elasticity and elastoplasticity footing cases, we found that physics-informed learning equipped with DRM-based loss functions shows more excellent accuracy in forwardly computing displacement but poor accuracy in predicting strain and stress. Physics-informed learning with CPM-based loss functions shows more excellent performance in inverse analysis than their forward-solving ability. The exponential acceleration method largely enhances the efficiency of inverse analysis without sacrificing accuracy. These new findings inspire the future application of physics-informed learning to engineering-scale elastoplastic problems.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"181 ","pages":"Article 107110"},"PeriodicalIF":5.3,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143324679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Homogenisation method for braced excavations stabilised with deep-mixed columns

IF 5.3 1区工程技术

Computers and Geotechnics Pub Date : 2025-02-05 DOI: 10.1016/j.compgeo.2025.107095

Sinem Bozkurt, Ayman Abed, Minna Karstunen

{"title":"Homogenisation method for braced excavations stabilised with deep-mixed columns","authors":"Sinem Bozkurt, Ayman Abed, Minna Karstunen","doi":"10.1016/j.compgeo.2025.107095","DOIUrl":"10.1016/j.compgeo.2025.107095","url":null,"abstract":"<div><div>The stabilisation of deep excavations using columnar inclusions introduces three-dimensional (3D) complexities into design calculations. Often the intricate nature of the wall-soil-column interaction is simulated using simplified averaging techniques based on elasticity theory. This paper introduces a numerical technique to accurately describe the nonlinear elastoplastic response of both stabilised and natural soft clay for the case of excavations stabilised with deep-mixed columns. The technique allows mapping the 3D problem into a plane-strain (2D) counterpart by replacing the composite material made of natural clay and a region of overlapping deep-mixed columns with an equivalent homogenised material. The stress–strain response of the homogenised continuum is computed with a volume averaging technique (VAT) based on the volume fraction of each component (i.e. clay and column). The technique is implemented into a 2D finite element code enabling an effective representation of the behaviour of each constituent represented by advanced elastoplastic material models. After presenting the theoretical background and implementation procedure, the proposed method was verified against the results from the 3D calculations. The technique emerges as an efficient tool for the numerical analysis of stabilised deep excavations since it allows for plane strain analysis to yield results akin to computationally expensive 3D analysis. Thus, the method can significantly reduce the computational costs and can facilitate the easier incorporation of sensitivity studies.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"181 ","pages":"Article 107095"},"PeriodicalIF":5.3,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Four-dimensional lattice spring method using a level set approach for contact problems in geomechanics

IF 5.3 1区工程技术

Computers and Geotechnics Pub Date : 2025-02-05 DOI: 10.1016/j.compgeo.2025.107124

Xin-Dong Wei, Gao-Feng Zhao

{"title":"Four-dimensional lattice spring method using a level set approach for contact problems in geomechanics","authors":"Xin-Dong Wei, Gao-Feng Zhao","doi":"10.1016/j.compgeo.2025.107124","DOIUrl":"10.1016/j.compgeo.2025.107124","url":null,"abstract":"<div><div>Lattice Spring Methods (LSM) have gained increasing attention in recent years due to their effectiveness in handling fracturing and nonlinear problems. However, their ability to address general contact issues in geomechanics remains limited. Directly handling contact using discrete geometry often results in local locking, a common challenge in particle-based methods like DEM and LSM. This work introduces a level set approach to overcome this limitation. Block and granular geometries are represented by a level set function, which is also employed to manage contact interactions between blocks and granules. A specialized contact algorithm is developed for the lattice model using a signed distance function (SDF) that accounts for lattice discretization. The new LS-4D-LSM demonstrates its capability to solve complex contact problems through various numerical examples, including both deformation and fracturing of blocks. Given that contact plays a key role in many geomechanics tests, incorporating realistic contact behavior into these analyses leads to a more accurate fit with experimentally observed data. This suggests that the digital twin concept could be a powerful tool for analyzing experimental data in geomechanics. The proposed method is also applicable to other numerical approaches, such as DEM, enhancing their ability to handle deformable and fragmentable blocks or granules.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"181 ","pages":"Article 107124"},"PeriodicalIF":5.3,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143357316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A fully Coupled thermal-hydrodynamic–chemical numerical model for simulating gas hydrate-bearing sediments dissociation based on peridynamic differential operator method

IF 5.3 1区工程技术

Computers and Geotechnics Pub Date : 2025-02-04 DOI: 10.1016/j.compgeo.2025.107099

Linfeng Zhang , Guorong Wang , Zhiyuan Li , Lin Zhong , Qiang Fu , Jiwei Wu , Mengdi Wu , Dongmei Liang , Yuhang Zheng

{"title":"A fully Coupled thermal-hydrodynamic–chemical numerical model for simulating gas hydrate-bearing sediments dissociation based on peridynamic differential operator method","authors":"Linfeng Zhang , Guorong Wang , Zhiyuan Li , Lin Zhong , Qiang Fu , Jiwei Wu , Mengdi Wu , Dongmei Liang , Yuhang Zheng","doi":"10.1016/j.compgeo.2025.107099","DOIUrl":"10.1016/j.compgeo.2025.107099","url":null,"abstract":"<div><div>During methane hydrate-bearing sediments (MHBS) extraction multiphase flow with heat transfer transitioning MHBS phase followed by pore dynamic evolution. Which involves a complex thermo-hydrodynamic (THC) coupled process. Effective theoretical and fully integrated numerical models are essential for evaluating the economic feasibility of gas hydrate production and comprehending the fundamental physical concepts. This study presents a novel approach to constructing a fully integrated THC numerical model by employing a peridynamic differential operator (PDDO). The dimensionless governing equations of Darcy’s law and the heat source approach are transformed into a non-local integral form. The Euler forward difference method is used for time integration. The accuracy and reliability of the newly developed PDDO THC model were tested by comparing it with experimental examples from other popular simulators, which provides an alternative to explicit modeling of the phase change process involving multiphase flow with heat transfer and may find comprehensive and useful applications to a variety of industrial and geophysical processes.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"180 ","pages":"Article 107099"},"PeriodicalIF":5.3,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143171743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A sparse-memory-encoding GPU-MPM framework for large-scale simulations of granular flows

IF 5.3 1区工程技术

Computers and Geotechnics Pub Date : 2025-02-04 DOI: 10.1016/j.compgeo.2025.107113

Hao Chen, Shiwei Zhao, Jidong Zhao

{"title":"A sparse-memory-encoding GPU-MPM framework for large-scale simulations of granular flows","authors":"Hao Chen, Shiwei Zhao, Jidong Zhao","doi":"10.1016/j.compgeo.2025.107113","DOIUrl":"10.1016/j.compgeo.2025.107113","url":null,"abstract":"<div><div>The Material Point Method (MPM) is increasingly recognized as an effective tool for simulating complex granular flows. While GPU computing has been widely used in MPM applications for large-scale problems, its heavy reliance on contiguous memory distribution can significantly hinder efficiency and limit simulation capabilities due to memory capacity constraints. This study presents a sparse-memory-encoding framework that incorporates advanced algorithms to address these limitations in large-scale simulations. We introduce a novel algorithm for atomic-free dual mapping between material points and nodes, in conjunction with warp-wise particle-to-grid mappings organized within a block-cell-material point hierarchy. Moreover, the framework features an efficient memory shift algorithm that optimizes memory usage for material properties. This optimization enables the seamless integration of commonly used material constitutive models, including elastic, elastoplastic, and hyper-plastic models, as well as various iteration schemes such as “update stress first”, “update stress last”, and “modified update stress last” within a cohesive framework. Furthermore, the framework accommodates incorporating diverse boundary conditions, such as Dirichlet, Neumann, and arbitrary-shaped rigid body contact, thus broadening its applicability to real-world engineering challenges, including landslides. The framework can effectively and efficiently handle large-scale, high-fidelity simulations of granular flows.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"180 ","pages":"Article 107113"},"PeriodicalIF":5.3,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143171740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental and numerical investigations of undrained stress relaxation behavior considering freeze-thaw-drying-wetting effects for saturated clay

IF 5.3 1区工程技术

Computers and Geotechnics Pub Date : 2025-02-01 DOI: 10.1016/j.compgeo.2025.107114

Weilie Zou , Qiuyang Pei , Xilin Xia , Zhong Han

{"title":"Experimental and numerical investigations of undrained stress relaxation behavior considering freeze-thaw-drying-wetting effects for saturated clay","authors":"Weilie Zou , Qiuyang Pei , Xilin Xia , Zhong Han","doi":"10.1016/j.compgeo.2025.107114","DOIUrl":"10.1016/j.compgeo.2025.107114","url":null,"abstract":"<div><div>The effects of freeze–thaw-drying-wetting cycles on undrained stress relaxation behavior are studied from the perspectives of physical experiments and numerical simulations using the proposed multi-set material point method (MPM) algorithm. The effectiveness of the established MPM model is validated by comparing the simulation results with experimental data. To gain insights into the microscopic characteristics of undrained stress relaxation, the evaluation focuses on the variations in elastic Green-Lagrangian strain, water pressure, water particle velocity, and solid particle space. The deviator stress relaxation and water pressure evolution are correlated with the decrease in elastic strain and spatial variation in water velocity, respectively. The stress relaxation process breaks the interparticle bonds and results in structural weakening. Freeze-thaw-drying-wetting cycles reduce the relaxed deviator stress within different relaxation stages and promote variation in water pressure, instability in water velocity field, and adjustment of solid particles.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"180 ","pages":"Article 107114"},"PeriodicalIF":5.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143171741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Phase field fracture modeling of cohesive-frictional materials like concrete and rock using the scaled boundary finite element method

IF 5.3 1区工程技术

Computers and Geotechnics Pub Date : 2025-02-01 DOI: 10.1016/j.compgeo.2025.107106

Penghao Zhang, Yunxuan Cui, Kurt Douglas, Chongmin Song, Adrian R. Russell

{"title":"Phase field fracture modeling of cohesive-frictional materials like concrete and rock using the scaled boundary finite element method","authors":"Penghao Zhang, Yunxuan Cui, Kurt Douglas, Chongmin Song, Adrian R. Russell","doi":"10.1016/j.compgeo.2025.107106","DOIUrl":"10.1016/j.compgeo.2025.107106","url":null,"abstract":"<div><div>Understanding and predicting the mechanisms and behaviors of crack propagations in engineering structures made of rock and concrete is important when producing reliable designs. This study proposes a phase field crack model suitable for cohesive-frictional materials such as rock and concrete. Novelty lies in introducing and coupling the multiaxial strength criterion for cohesive-frictional materials and the micro-damage evolution law within the fracture process zone within the basic phase field method. Another novel feature is the decomposition of volumetric and deviatoric components of the stiffness matrices in the precomputation phase of the scaled boundary finite element method. The combination of this numerical technique with the proposed constitutive model enables the effective and efficient simulation of compression-shear cracks. Novelty also lies in integrating the proposed model with scaling theory. This keeps the computational cost for large-scale problems within an acceptable range. The technique we adopt to achieve this advancement involves making the simulation results insensitive to the characteristic length. This improvement allows the characteristic length for large-scale problems to be uniquely determined and larger than the value used at the laboratory scale. This enables the use of coarser meshes, reducing the computational resources needed for simulating large-scale problems.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"180 ","pages":"Article 107106"},"PeriodicalIF":5.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Interaction between piles and layered fractional viscoelastic soils considering groundwater level

IF 5.3 1区工程技术

Computers and Geotechnics Pub Date : 2025-01-31 DOI: 10.1016/j.compgeo.2025.107119

Zhi Yong Ai, He Wei Kuang, Zi Kun Ye, Qing Song Lu

{"title":"Interaction between piles and layered fractional viscoelastic soils considering groundwater level","authors":"Zhi Yong Ai, He Wei Kuang, Zi Kun Ye, Qing Song Lu","doi":"10.1016/j.compgeo.2025.107119","DOIUrl":"10.1016/j.compgeo.2025.107119","url":null,"abstract":"<div><div>Based on the time-varying solution of layered fractional viscoelastic soils considering groundwater level, the interaction between soils and piles is studied by a finite element–boundary element coupling method. The single pile is regarded as a one-dimensional compressible bar to establish its stiffness matrix equation by the finite element method. Then, the fundamental solutions of layered fractional viscoelastic soils considering groundwater level are used as kernel functions in the boundary element method. According to the displacement continuity condition on the pile-soil interface, the interaction between single pile and soils is solved. Furthermore, by incorporating the pile-pile interaction as well as the balance and coordination conditions of the rigid cap, the solution of the single pile is extended to the pile group. Finally, the correctness of the presented method and program is validated, and several examples are designed to explore the effects of groundwater level, soil properties, pile parameters, and soil stratification on the pile-soil interaction. The analysis results show that, as the groundwater level declines, the displacement of the pile at the initial moment increases, and the reaction forces of center and side piles increase. Moreover, the increase of fractional order can accelerate the rate of pile displacement, reduce the axial force on the upper pile body, and decrease the reaction force at the top of the center and side piles.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"180 ","pages":"Article 107119"},"PeriodicalIF":5.3,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143171744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Wave propagation in an ocean site considering fractional viscoelastic constitution of porous seabed

IF 5.3 1区工程技术

Computers and Geotechnics Pub Date : 2025-01-31 DOI: 10.1016/j.compgeo.2025.107098

Sen Zheng , Weihua Li , Yexin Wan , Zhe Yang , Sainan Zhu

{"title":"Wave propagation in an ocean site considering fractional viscoelastic constitution of porous seabed","authors":"Sen Zheng , Weihua Li , Yexin Wan , Zhe Yang , Sainan Zhu","doi":"10.1016/j.compgeo.2025.107098","DOIUrl":"10.1016/j.compgeo.2025.107098","url":null,"abstract":"<div><div>Wave propagation in an ocean site is an essential research topic in various scientific fields, such as offshore geotechnical engineering, ocean seismology, and underwater acoustics. Previous studies have considered the seabed soil as elastic or poroelastic, ignoring the viscoelastic characteristics of its solid skeleton. Based on the fractional-derivative viscoelastic theory and the modified Biot theory, considering the flow-independent viscosity related to solid skeleton, this paper proposes a generalized viscoelastic wave equation for a fluid-saturated porous medium. The equation has a flexible mathematical form to describe soil rheological properties more accurately through fractional order. On this basis, the total wave field equation of an ocean site, modeled as the fluid–poroviscoelastic–solid media, is established. Then an analytical solution for wave propagation in an ocean site subjected to obliquely incident P and SV waves is obtained, and its degeneration and extension are studied. The proposed method is comprehensively validated through experiment, analytical, and numerical methods. Finally, a parameter analysis is performed to investigate the effects of water depth, seabed properties (including viscoelastic parameters, fractional order and permeability), and incident angle on the seismic response of a poroviscoelastic seabed.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"180 ","pages":"Article 107098"},"PeriodicalIF":5.3,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0