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Mechanical behaviours of bedded sandstone under hydromechanical coupling
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作者 Junwen Zhang Zhixiang Song +7 位作者 Lichao Zhang Shaokang Wu Shanyong Wang Yang Zhang Xukai Dong Jinxin Wang Yanbo Han Baohua Kan 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第4期1245-1261,共17页
The combination of the dipping effect and hydromechanical(H-M)coupling effect can easily lead to water inrush disasters in water-rich roadways with different dip angles in coal mines.Therefore,H-M coupling tests of be... The combination of the dipping effect and hydromechanical(H-M)coupling effect can easily lead to water inrush disasters in water-rich roadways with different dip angles in coal mines.Therefore,H-M coupling tests of bedded sandstones under identical osmotic pressure and various confining pressures were conducted.Then,the evolution curves of stress-strain,permeability and damage,macro-and mesoscopic failure characteristics were obtained.Subsequently,the mechanical behaviour was characterized,and finally the failure mechanism was revealed.The results showed that:(1)The failure of the sandstone with the bedding angle of 45°or 60°was the structure-dominant type,while that with the bedding angle of 0°,30°or 90°was the force-dominant type.(2)When the bedding angle was in the range of(0°,30°)or(45°,90°),the confining pressure played a dominant role in influencing the peak strength.However,withinβ∈(30°,45°),the bedding effect played a dominant role in the peak strength.(3)With the increase in bedding angle,the cohesion increased first,then decreased and finally increased,while the internal friction angle was the opposite.(4)When the bedding angle was 0°or 30°,the“water wedging”effect and the“bedding buckling”effect would lead to the forking or converging shear failure.When the bedding angle was 45°or 60°,the sliding friction effect would lead to the shear slipping failure.When the bedding angle was 90°,the combination of the“bedding buckling”effect and shear effect would lead to the mixed tension-shear failure.The above conclusions obtained are helpful for the prevention of water inrush disasters in water-rich roadways with different dips in coal mines. 展开更多
关键词 Hydromechanical coupling Bedded sandstones Mechanical behaviour Bedding effect Failure mechanism
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Dynamic tensile behaviour and crack propagation of coal under coupled static-dynamic loading 被引量:20
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作者 Xianjie Hao Weisheng Du +4 位作者 Yixin Zhao Zhuowen Sun Qian Zhang Shaohua Wang Haiqing Qiao 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2020年第5期659-668,共10页
The fracture behaviour and crack propagation features of coal under coupled static-dynamic loading conditions are important when evaluating the dynamic failure of coal.In this study,coupled static-dynamic loading test... The fracture behaviour and crack propagation features of coal under coupled static-dynamic loading conditions are important when evaluating the dynamic failure of coal.In this study,coupled static-dynamic loading tests are conducted on Brazilian disc(BD)coal specimens using a modified split Hopkinson pressure bar(SHPB).The effects of the static axial pre-stress and loading rate on the dynamic tensile strength and crack propagation characteristics of BD coal specimens are studied.The average dynamic indirect tensile strength of coal specimens increases first and then decreases with the static axial pre-stress increasing.When no static axial pre-stress is applied,or the static axial pre-stress is 30%of the static tensile strength,the dynamic indirect tensile strength of coal specimens shows an increase trend as the loading rate increases.When the static axial pre-stress is 60%of the static tensile strength,the dynamic indirect tensile strength shows a fluctuant trend as the loading rate increases.According to the crack propagation process of coal specimens recorded by high-speed camera,the impact velocity influences the mode of crack propagation,while the static axial pre-stress influences the direction of crack propagation.The failure of coal specimens is a coupled tensile-shear failure under high impact velocity.When there is no static axial pre-stress,tensile cracks occur in the vertical loading direction.When the static axial pre-stress is applied,the number of cracks perpendicular to the loading direction decreases,and more cracks occur in the parallel loading direction. 展开更多
关键词 COAL coupled static-dynamic loading SHPB Dynamic fracture behaviour Crack propagation
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Quantum dynamic behaviour in a coupled cavities system 被引量:4
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作者 彭俊 邬云文 李小娟 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第6期26-32,共7页
The dynamic behaviour of the two-site coupled cavities model which is doped with ta wo-level system is investi-gated. The exact dynamic solutions in the general condition are obtained via Laplace transform. The simple... The dynamic behaviour of the two-site coupled cavities model which is doped with ta wo-level system is investi-gated. The exact dynamic solutions in the general condition are obtained via Laplace transform. The simple analytical solutions are obtained in several particular cases, which demonstrate the clear and simple physical picture for the quan-tum state transition of the system. In the large detuning or hoppling case, the quantum states transferring between qubits follow a slow periodic oscillation induced by the very weak excitation of the cavity mode. In the large coupling case, the system can be interpreted as two Jaynes-Cummings model subsystems which interact through photon hop between the two cavities. In the case of λ≈△〉〉 g, the quantum states transition of qubits is accompanied by the excitation of the cavity, and the cavity modes have the same dynamic behaviours and the amplitude of probability is equM to 0.25 which does not change with the variation of parameter. 展开更多
关键词 coupled cavities quantum dynamics behaviour DETUNING two-level system
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EFFECTS OF COUPLING AGENTS ON THE CRYSTALLIZATION BEHAVIOR OF PP/T-ZnOw COMPOSITES 被引量:2
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作者 Yong Wang Zheng-bao He Zuo-wan Zhou 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2007年第6期565-572,共8页
The objectives of this paper are to understand the crystallization behavior of polypropylene (PP) composites with surface modified tetra-needle-shaped zinc oxide whisker (T-ZnOw). T-ZnOw was surface modified with ... The objectives of this paper are to understand the crystallization behavior of polypropylene (PP) composites with surface modified tetra-needle-shaped zinc oxide whisker (T-ZnOw). T-ZnOw was surface modified with different coupling agents, such as silane coupling agents (KH-550, KH-560) and titanate coupling agent (NDZ-105), in order to improve the compatibility between PP and T-ZnOw. DSC and POM were used to characterize the melt and crystallization behavior and the crystalline structures of the composites, respectively. The results show that the surface modified T-ZnOw acts as a nucleating agent of PP crystallization, depending on the coupling agent used for modification. KH-550 and KH-560 have more apparent role in improving the interfacial interaction than NDZ-105 and induce PP crystallization at higher temperature and with smaller spherulites size. The results also suggest that the crystallization behavior depends on not only the content of coupling agent, but also the content of the surface modified T-ZnOw used in the composites. 展开更多
关键词 PP/T-ZnOw Crystallization behaviour coupling agent.
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Material point method simulation of hydro-mechanical behaviour in twophase porous geomaterials: A state-of-the-art review 被引量:2
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作者 Xiangcou Zheng Shuying Wang +1 位作者 Feng Yang Junsheng Yang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第6期2341-2350,共10页
The material point method(MPM)has been gaining increasing popularity as an appropriate approach to the solution of coupled hydro-mechanical problems involving large deformation.In this paper,we survey the current stat... The material point method(MPM)has been gaining increasing popularity as an appropriate approach to the solution of coupled hydro-mechanical problems involving large deformation.In this paper,we survey the current state-of-the-art in the MPM simulation of hydro-mechanical behaviour in two-phase porous geomaterials.The review covers the recent advances and developments in the MPM and their extensions to capture the coupled hydro-mechanical problems involving large deformations.The focus of this review is aiming at providing a clear picture of what has or has not been developed or implemented for simulating two-phase coupled large deformation problems,which will provide some direct reference for both practitioners and researchers. 展开更多
关键词 coupled problems Hydro-mechanical behaviour Large deformation Material Point Method(MPM)
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The coupled hydro-mechanical behaviours of compacted crushed Callovo-Oxfordian argillite
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作者 Chaosheng Tang A. M. Tang +2 位作者 Y. J. Cui P. Delage Bin Shi 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2010年第1期86-90,共5页
Callovo-Oxfordian (COx) argillite obtained from the excavation of high-level radioactive waste geological disposal has been evaluated as an alternative sealing/backfill material in France. This paper presents an exp... Callovo-Oxfordian (COx) argillite obtained from the excavation of high-level radioactive waste geological disposal has been evaluated as an alternative sealing/backfill material in France. This paper presents an experimental investigation into the hydro-mechanical behaviour of compacted crushed COx argillite. A series of oedorneter compressive tests including various loading-unloading cycles were conducted on COx argillite powders at different initial water contents. After reaching the desired dry density (2.0 Mg/m^3), the vertical stress was reduced to different levels (7.0 and 0.5 MPa) and the compacted sample was then flooded under constant volume conditions while measuring the changes in the vertical stress. It was found that the initial water content significantly affects the compressive behaviour. The measured saturated hydraulic conductivity is less than 1×10^-10m/s. 展开更多
关键词 compacted argillite compressive behaviour dry density water content hydro-mechanical coupling behaviours
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Risk behaviours associated with HIV and AIDS among couples in Rwamiko Sector, Gicumbi District, Rwanda
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作者 Jean Marie Vianney Tuyisenge Erigene Rutayisire 《Life Research》 2023年第3期59-65,共7页
Background:Risk behaviours have been linked to the spread of the Human Immunodeficiency Virus(HIV)epidemic in both urban and rural areas.Despite the progress made in the fight against HIV,it remains a public health co... Background:Risk behaviours have been linked to the spread of the Human Immunodeficiency Virus(HIV)epidemic in both urban and rural areas.Despite the progress made in the fight against HIV,it remains a public health concern worldwide.Risk behaviours such as not using condoms,having multiple sexual partners,and engaging in early sexual activity increase the risk of HIV infection.Therefore,it is important to assess these risk behaviours and understand the relationship between different factors and HIV,specifically among couples,in order to better understand the dynamics of the epidemic.The main objective of this study was to assess risk behaviours for HIV and AIDS among couples in Rwamiko sector,Gicumbi District,and suggest appropriate interventions for this group.Methods:This cross-sectional survey aimed to assess associated HIV and AIDS risk behaviours among couples in Rwamiko Sector,Gicumbi District,in order to determine the dynamics of the epidemic in this group and suggest appropriate interventions.Data was collected using a self-administered questionnaire and a multistage cluster random sampling technique.The collected data was then computed,analyzed,and presented in the form of tables and figures.Descriptive statistics were used to analyze all variables.Multivariate logistic regression was used to calculate odds ratios and 95%confidence intervals(CI)to investigate the relationship between the assessed factors,such as independent and dependent variables.The association between the studied factors was described using odds ratios with 95%CIs.Results:The majority of respondents were in the age group of 30-39 years.All respondents were married,and approximately 45%had completed primary education.The majority of respondents were unemployed.Respondents reported receiving HIV information from multiple sources,including radio,TV,films,school,church,health workers,parents,and friends.The findings of this study showed that some participants had knowledge about HIV transmission and prevention,while others did not.The proportion of respondents with a high level of HIV and AIDS knowledge was 30.61%(n=60),while moderate knowledge accounted for 53.57%(n=105).Furthermore,the proportion of respondents with a low level of knowledge on HIV and AIDS was 15.81%(n=31).The attitude towards HIV and AIDS was positive for 58.16%(n=114)of respondents,while 41.83%(n=82)had a negative attitude.None of the respondents reported using injection drugs.Significant associations were found between age(P-value=0.002,odds ratio(OR)=3.4,95%CI=1.59-7.67),gender(p=0.001,OR=2.6,95%CI=1.44-4.68),and alcohol consumption.There was also an association between age(P=0.001,OR=5.13,95%CI=2.04-12.91)and having multiple sexual partners.Conclusion:The majority of couples in Rwamiko Sector,Gicumbi District have a moderate level of knowledge and a positive attitude towards HIV and AIDS.However,the proportions of respondents with a low level of knowledge and a negative attitude should not be overlooked.The results of this study suggest the need to improve communication messages related to HIV,its transmission risks,and safer sexual behavior,particularly among couples in Rwamiko Sector,Gicumbi District. 展开更多
关键词 Risk behaviour couples Rwamiko Sector Gicumbi District
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Novel four-wing and eight-wing attractors using coupled chaotic Lorenz systems 被引量:2
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作者 Giuseppe Grassi 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第9期3247-3251,共5页
This paper presents the problem of generating four-wing (eight-wing) chaotic attractors. The adopted method consists in suitably coupling two (three) identical Lorenz systems. In analogy with the original Lorenz s... This paper presents the problem of generating four-wing (eight-wing) chaotic attractors. The adopted method consists in suitably coupling two (three) identical Lorenz systems. In analogy with the original Lorenz system, where the two wings of the butterfly attractor are located around the two equilibria with the unstable pair of complex-conjugate eigenvalues, this paper shows that the four wings (eight wings) of these novel attractors axe located around the four (eight) equilibria with two (three) pairs of unstable complex-conjugate eigenvalues. 展开更多
关键词 chaotic attractors multi-wing attractor coupled Lorenz systems dynamical behaviours
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The magnetization reversal behaviour for SmCo_(6.8)Zr_(0.2) and SmCo_(6.8)Zr_(0.2)/α-(Fe,Co) nanocrystalline magnets at low temperature
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作者 刘壮 陈仁杰 +1 位作者 李东 闫阿儒 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第6期528-533,共6页
This paper reports that the SmCo6.8Zr0.2 nanocrystalline permanent magnets and SmCo6.8Zr0.2/a-(Fe,Co) nanocomposite permanent magnets are successfully produced by mechanical alloying and subsequently annealing at 70... This paper reports that the SmCo6.8Zr0.2 nanocrystalline permanent magnets and SmCo6.8Zr0.2/a-(Fe,Co) nanocomposite permanent magnets are successfully produced by mechanical alloying and subsequently annealing at 700℃ for 10 minutes. The x-ray diffraction results show that the phase structure of SmCo6.8Zr0.2 nanocrystalline permanent magnets is composed of SmCo7 phase and SmCo6.8Zr0.2/a-(Fe,Co) nanocomposite permanent magnets is composed of SmCo7 and a-(Fe,Co) phases. The mechanism of magnetization reversal is mainly controlled by inhomogeneous domain wall pinning in SmCo6.8Zr0.2 and SmCo6.8Zr0.2/a-(Fe,Co) magnets. The inter-grain exchange interaction at low temperature is investigated, which shows that the inter-grain exchange interaction of SmCo6.8Zr0.2/a-(Fe,Co) magnets increases greatly by the decrease of the measured temperature. According to Amirr-H/Hcj, Amrev-H/Hcj and Xirr-H/Hcj curves at room temperature and 100 K, the changes of irreversible and reversible magnetization behaviours of SmCo6.8Zr0.2 and SmCo6.8Zr0.2/a-(Fe,Co) magnets with the decreasing temperature are analysed in detail. The magnetic viscosity and the activation volume of SmCo6.8Zr0.2 and SmCo6.8Zr0.2/a-(Fe,Co) magnets at different temperatures are also studied. 展开更多
关键词 nanocrystalline magnets coercivity mechanism inter-grain exchange coupling magne- tization reversal behaviour
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Isotropic Elastoplasticity Fully Coupled with Non-Local Damage
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作者 M. Almansba K. Saanouni N. E. Hannachi 《Engineering(科研)》 2010年第6期420-431,共12页
This paper presents a simple damage-gradient based elastoplastic model with non linear isotropic hardening in order to regularize the associated initial and boundary value problem (IBVP). Using the total energy equiva... This paper presents a simple damage-gradient based elastoplastic model with non linear isotropic hardening in order to regularize the associated initial and boundary value problem (IBVP). Using the total energy equivalence hypothesis, fully coupled constitutive equations are used to describe the non local damage induced softening leading to a mesh independent solution. An additional partial differential equation governing the evolution of the non local isotropic damage is added to the classical equilibrium equations and associated weak forms derived. This leads to discretized IBVP governed by two algebric systems. The first one, associated with equilibrium equations, is highly non linear and can be solved by an iterative Newton Raphson method. The second one, related to the non local damage, is a linear algebric system and can be solved directly to compute the non local damage variable at each load increment. Two fields, linear interpolation triangular element with additional degree of freedom is terms of the non local damage variable is constructed. The non local damage variable is then transferred from mesh nodes to the quadrature (or Gauss) points to affect strongly the elastoplastic behavior. Two simple 2D examples are worked out in order to investigate the ability of proposed approach to deliver a mesh independent solution in the softening stage. 展开更多
关键词 ELASTOPLASTIC DAMAGE behaviour coupling ISOTROPIC HARDENING DAMAGE GRADIENT Finis
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温度与荷载联合作用下能源锚杆的热力响应特性数值模拟研究
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作者 李伟强 孔纲强 +2 位作者 孙广超 陈玉 许晓亮 《三峡大学学报(自然科学版)》 CAS 北大核心 2024年第3期57-63,共7页
能源锚杆是一种由地源热泵技术与支护锚杆相结合的建筑节能减碳新技术.然而,目前针对温度影响下锚杆的热力响应机理尚不清楚.基于多场耦合数值模拟方法,探讨温度、锚杆线膨胀系数、锚杆直径、土体导热系数及荷载等因素对能源锚杆热-力... 能源锚杆是一种由地源热泵技术与支护锚杆相结合的建筑节能减碳新技术.然而,目前针对温度影响下锚杆的热力响应机理尚不清楚.基于多场耦合数值模拟方法,探讨温度、锚杆线膨胀系数、锚杆直径、土体导热系数及荷载等因素对能源锚杆热-力特性的影响.研究结果表明:常温锚杆受拉时,锚头位移随荷载的增大而增加;温度下降15℃时,锚头平均位移较常温锚杆降低-1.34 mm(约为锚杆直径的1.0%);温度上升15℃时,锚头平均位移较常温锚杆增加0.89mm(约为锚杆直径的0.68%);换热过程中,锚杆温度的升高会引起杆体轴力的减小;在同一加热温度和荷载条件下,锚头位移随着锚杆的线膨胀系数增大而增大,锚杆轴力随着锚杆的线膨胀系数增大而减小;锚杆直径的增大会导致锚头位移的减小.试验结果对能源锚杆的设计和施工提供了一定的参考和依据. 展开更多
关键词 能源锚杆 热力响应 数值模拟 多场耦合
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钢管混凝土加劲混合结构轴心受压工作机理及可靠性分析
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作者 马丹阳 杨志程 《土木工程学报》 EI CSCD 北大核心 2024年第3期16-29,80,共15页
钢管混凝土加劲混合结构是由内置钢管混凝土部分和外包钢筋混凝土部分混合而成的结构,由于其在承载力、刚度和延性上的优势,已在工程结构中得到应用。国家标准《钢管混凝土混合结构技术标准》(GB/T 51446—2021)给出其轴压承载力和刚度... 钢管混凝土加劲混合结构是由内置钢管混凝土部分和外包钢筋混凝土部分混合而成的结构,由于其在承载力、刚度和延性上的优势,已在工程结构中得到应用。国家标准《钢管混凝土混合结构技术标准》(GB/T 51446—2021)给出其轴压承载力和刚度计算方法。但以往研究主要针对单一参数,尚缺少多参数耦合作用下受力机理研究;且亟需验证承载力计算方法的可靠性,为各行业下的安全性设计提供依据。该文首先建立了轴心受压试验数据库,分析了影响该类结构轴压性能的关键参数;之后,运用验证后的精细化有限元模型开展多参数耦合作用分析,明晰多参数耦合作用对结构刚度、承载力的影响规律,弥补试验研究的局限性,并进一步揭示结构在短期、长期荷载下的内力分布规律,为长期服役下安全性分析提供依据。在参数分析的基础上,开展可靠性分析,确定该类结构在房屋建筑、铁路桥涵、公路桥涵和港口工程中的可靠度指标,验证国家标准中轴压承载力设计方法的可靠性。 展开更多
关键词 钢管混凝土加劲混合结构 轴心受压性能 参数化建模 多参数耦合作用 可靠性分析
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U型管埋地换热器长期性能的实验研究与灰色预测 被引量:15
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作者 赵军 王华军 +2 位作者 宋著坤 陈志豪 李新国 《太阳能学报》 EI CAS CSCD 北大核心 2006年第11期1137-1141,共5页
对实际运行的U型埋地换热器长期性能进行了实验研究。根据灰色理论,建立了换热量和传热系数等参数的GM(1,1)预测模型,预测结果与实际测试具有较好的吻合性。管埋地换热器在长期运行过程中,由于冬夏负荷之间的不平衡问题,夏季工... 对实际运行的U型埋地换热器长期性能进行了实验研究。根据灰色理论,建立了换热量和传热系数等参数的GM(1,1)预测模型,预测结果与实际测试具有较好的吻合性。管埋地换热器在长期运行过程中,由于冬夏负荷之间的不平衡问题,夏季工况很可能会出现恶化现象,其工况可分为过渡区、稳定区和衰减区3个阶段。引入无量纲运行时间τ来表征平均传热系数的长期运行特性,即K=aτb,并初步确定了夏季工况的时间域:过渡区τ=0~25%,稳定区τ=25%~80%,衰减区τ=80%~100%。灰色预测能够为系统的稳定运行、性能评价以及进一步优化提供定量化参考依据。 展开更多
关键词 地源热泵 埋地换热器 长期性能 灰色预测
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压缩过程中非饱和膨胀土体变特征与持水特性的水力耦合效应 被引量:8
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作者 周葆春 孔令伟 +2 位作者 梁维云 马全国 张斌 《岩土工程学报》 EI CAS CSCD 北大核心 2015年第4期629-640,共12页
土体压缩是岩土工程领域的基本问题。压缩过程中非饱和土的力学与水力学行为是同时发生且相互影响的,有必要统一考察体变特征与持水特性的水力耦合效应。为此,以荆门弱膨胀土为研究对象,开展土中水密度试验、饱和与控制吸力下的非饱和... 土体压缩是岩土工程领域的基本问题。压缩过程中非饱和土的力学与水力学行为是同时发生且相互影响的,有必要统一考察体变特征与持水特性的水力耦合效应。为此,以荆门弱膨胀土为研究对象,开展土中水密度试验、饱和与控制吸力下的非饱和一维压缩试验,准确测量了压缩与卸荷回弹过程中孔隙比–重力含水率–吸力–竖向净应力关系,探讨了水力耦合状况下非饱和膨胀土的体变特征与持水特性规律,并建立相应本构描述。结论如下:1加载段,非饱和压缩曲线均发生明显转折,体现出屈服行为;随吸力增大,压缩曲线依次发生"穿越"现象;卸载段大体呈线性,其斜率随吸力增大而降低。提出能够描述干缩、压缩、卸荷体胀、屈服、压缩性与卸荷回弹性随吸力变化等行为的非饱和土体变方程,可直接用于分层总和法计算。2不同吸力下重力含水率变化存在较大差异;压缩至2941.8 k Pa时,不同吸力下含水率非常接近。吸力与竖向净应力对含水率变化的耦合影响可用3参数Logistic函数描述。3压缩过程中饱和度随竖向净应力增大而增大,卸荷过程中随竖向净应力降低亦增大。采用饱和度或重力含水率,对压缩过程中的水力路径会出现"湿化"与"脱湿"的不同判断,即水力耦合状况下土体表现出复杂的持水状态变化特征。 展开更多
关键词 非饱和土 压实膨胀土 体变特征 持水特性 吸力 水力耦合 饱和度 土中水密度
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热-水-力耦合作用下非饱和土变形特性的弹塑性模拟 被引量:7
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作者 蔡国庆 郭艳鑫 +2 位作者 李舰 张雪东 赵成刚 《岩土力学》 EI CAS CSCD 北大核心 2017年第4期1060-1068,共9页
在已有的非饱和土水-力耦合模型基础上,耦合考虑温度影响,建立了一个热-水-力耦合作用下非饱和土弹塑性本构模型。该模型以土骨架平均应力、修正吸力和温度为应力状态变量,以土骨架应变、饱和度和熵为应变状态变量。通过引入与温度相关... 在已有的非饱和土水-力耦合模型基础上,耦合考虑温度影响,建立了一个热-水-力耦合作用下非饱和土弹塑性本构模型。该模型以土骨架平均应力、修正吸力和温度为应力状态变量,以土骨架应变、饱和度和熵为应变状态变量。通过引入与温度相关的屈服面(LY、TY)以及相应的硬化规律来考虑温度对土体变形的影响。利用建立的模型,对文献中不同吸力和温度条件下的等向压缩和三轴排水剪切试验进行预测,预测结果表明,该模型能够较好地定量描述热-水-力耦合作用下非饱和土的变形特性。 展开更多
关键词 非饱和土 热-水-力耦合 弹塑性本构模型 变形特性
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大分子偶联剂对PVC/CaCO_3复合体系性能的作用 被引量:3
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作者 张邦华 古巨明 +3 位作者 周庆业 宋谋道 郝广杰 张莹 《塑料工业》 CAS CSCD 北大核心 1995年第2期31-34,25,共5页
通过钛酸四异丙酯(TPT)与甲基丙烯酸甲酯-丙烯酸丁酯-丙烯酸(MMA-BA-AA)共聚物和第三组分焦磷酸二异辛酯(或硬脂酸)合成出新型大分子钛酸酯偶联剂(MTCA),处理CaCO_3填充聚氯乙烯(PVC).对PVC/CaCO_3复合体系的形态,动态力学行为(?)热稳... 通过钛酸四异丙酯(TPT)与甲基丙烯酸甲酯-丙烯酸丁酯-丙烯酸(MMA-BA-AA)共聚物和第三组分焦磷酸二异辛酯(或硬脂酸)合成出新型大分子钛酸酯偶联剂(MTCA),处理CaCO_3填充聚氯乙烯(PVC).对PVC/CaCO_3复合体系的形态,动态力学行为(?)热稳定性进行了研究.结果表明,MTCA可增加PVC与CaCO_3之间的相互作用,改善了体系的相态结构,提高了体系的热稳定性和PVC的玻璃化转变温度. 展开更多
关键词 偶联剂 复合体系 热稳定性 聚氯乙烯 碳酸钙
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膨胀性非饱和土的双尺度毛细–弹塑性变形耦合模型 被引量:12
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作者 李舰 赵成刚 黄启迪 《岩土工程学报》 EI CAS CSCD 北大核心 2012年第11期2127-2133,共7页
从宏观和微观角度,在已有的膨胀性非饱和土的双尺度本构模型BExM和湿陷性非饱和土的毛细–弹塑性变形耦合模型的基础上,发展和建立了一个可预测膨胀性非饱和土的毛细滞回和力学行为耦合的双尺度本构模型。模型考虑了土体微观结构的体变... 从宏观和微观角度,在已有的膨胀性非饱和土的双尺度本构模型BExM和湿陷性非饱和土的毛细–弹塑性变形耦合模型的基础上,发展和建立了一个可预测膨胀性非饱和土的毛细滞回和力学行为耦合的双尺度本构模型。模型考虑了土体微观结构的体变及其对宏观结构行为的影响,以及毛细和力学行为之间的耦合作用。对已有的膨胀性非饱和土的常净应力下吸力循环试验进行预测,预测结果表明该模型能够定量地描述膨胀性非饱和土的毛细和力学行为。 展开更多
关键词 非饱和膨胀土 弹塑性本构模型 毛细–弹塑性变形耦合模型 双尺度
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非饱和土的水力和力学特性及其弹塑性描述 被引量:42
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作者 孙德安 《岩土力学》 EI CAS CSCD 北大核心 2009年第11期3217-3231,共15页
简单回顾了非饱和土本构模型研究的发展历程,总结了近几年非饱和土弹塑性本构模型最新研究成果,重点介绍了能统一模拟非饱和土水力性状和力学性状耦合的弹塑性本构模型。通过对建立模型过程中的几个核心问题讨论,较详细地说明该类模型... 简单回顾了非饱和土本构模型研究的发展历程,总结了近几年非饱和土弹塑性本构模型最新研究成果,重点介绍了能统一模拟非饱和土水力性状和力学性状耦合的弹塑性本构模型。通过对建立模型过程中的几个核心问题讨论,较详细地说明该类模型的结构、性能以及相关问题。非饱和土水力性状的滞回性用假定存在饱和度弹性区间的弹塑性过程来模拟;该类耦合模型不仅考虑了吸力对非饱和土水力性状和力学性状的影响,还考虑了饱和度对应力-应变关系和强度的影响以及土体变形对土-水特征曲线的影响。用同一套模型参数,耦合模型可统一预测在吸力控制或含水率控制下沿各种应力路径下非饱和土的水力-力学特性,并简单介绍了膨胀性非饱和土的弹塑性本构模型以及耦合模型在有限元数值计算中的应用。 展开更多
关键词 非饱和土 弹塑性模型 应力-应变关系 水力特性 耦合
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环境土工基本理论及工程应用 被引量:112
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作者 陈云敏 《岩土工程学报》 EI CAS CSCD 北大核心 2014年第1期1-46,共46页
随着工业化和城市化的快速发展,各类固体废弃物产量迅速增大,地下水土污染不断加剧,人类赖以生存的环境日益恶化。岩土工程研究者力图利用岩土工程的原理和方法来研究和解决这样的环境问题,并逐步形成了岩土工程学科的一个新兴分支——... 随着工业化和城市化的快速发展,各类固体废弃物产量迅速增大,地下水土污染不断加剧,人类赖以生存的环境日益恶化。岩土工程研究者力图利用岩土工程的原理和方法来研究和解决这样的环境问题,并逐步形成了岩土工程学科的一个新兴分支——环境土工。环境土工问题伴随着生化反应、物理变化和机械运动等过程,目前国内外尚未建立统一的基本理论体系。该文论述了土体的生化反应、骨架变形、孔隙水运移、溶质迁移和孔隙气运移机理,并建立了考虑生化反应–骨架变形–水气运移–溶质迁移耦合作用的模型及其控制方程,界定并明确了模型参数及测试方法;揭示了高厨余城市固体废弃物填埋场存在严重的生化降解酸化抑制、骨架弱化和液气传导相互阻滞现象,以及城市固体废弃物压缩变形和液气产生及运移、污染物迁移与土体固结相互作用、污染物击穿防污屏障及覆盖屏障防水闭气的内在机理;结合笔者研究团队近二十年的环境土工研究和工程实践积累,总结了所提出的填埋场固废降解程度、渗滤液产量、填埋气收集率、填埋体沉降与填埋场容量、填埋场边坡稳定、防污屏障服役寿命评价方法以及所研发的填埋场液气立体导排、新型防污屏障和TDR污染土勘察技术的合理性和可靠性,并给出了工程应用实例。 展开更多
关键词 环境土工 生化反应 骨架变形 水气运移 溶质迁移 耦合作用
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常法向刚度条件下岩石节理剪切-渗流特性试验研究 被引量:17
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作者 夏才初 喻强锋 +2 位作者 钱鑫 桂洋 庄小清 《岩土力学》 EI CAS CSCD 北大核心 2020年第1期57-66,77,共11页
为研究常刚度(CNS)边界条件下节理的剪切-渗流耦合特性,针对3种不同节理粗糙度的复制节理试样进行了3种不同刚度、3种不同渗透水压力条件下的剪切-渗流试验,全面系统地分析了法向刚度、渗透水压和节理粗糙度等因素对节理剪切过程中力学... 为研究常刚度(CNS)边界条件下节理的剪切-渗流耦合特性,针对3种不同节理粗糙度的复制节理试样进行了3种不同刚度、3种不同渗透水压力条件下的剪切-渗流试验,全面系统地分析了法向刚度、渗透水压和节理粗糙度等因素对节理剪切过程中力学特性和渗流特性的影响。试验结果表明:节理峰值剪切强度随法向刚度的增加而增加,流量、等效水力开度和透过率随法向刚度的增加而减小;节理峰值剪切强度和法向位移均随渗透水压的增大而减小,流量、等效水力开度和透过率随法向刚度的增加而增加;通过节理面的流量随节理粗糙度的增加而减小。剪切过程中流量、等效水力开度和透过率均呈现类似于节理剪胀的三阶段变化规律:快速增长阶段、增速变缓阶段和稳定阶段;稳定阶段流量随法向刚度和渗透水压的变化近似呈线性关系,随着渗透水压的增加,粗糙程度较高的节理流速较慢。 展开更多
关键词 节理 剪切-渗流耦合特性 法向刚度 渗透水压 节理粗糙度
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