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固结比对饱和砂土液化的影响研究 被引量:10
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作者 王星华 周海林 《中国铁道科学》 EI CAS CSCD 北大核心 2001年第6期121-126,共6页
在影响砂土液化的众多因素中 ,固结比的作用已经引起了广大科研工作者的注意 ,研究表明这是影响饱和砂土液化的一个重要因素 ,本文通过动三轴实验 ,研究了在不同固结比下砂土的液化全过程 ,分析表明 ,固结比影响了砂土液化过程中的应力... 在影响砂土液化的众多因素中 ,固结比的作用已经引起了广大科研工作者的注意 ,研究表明这是影响饱和砂土液化的一个重要因素 ,本文通过动三轴实验 ,研究了在不同固结比下砂土的液化全过程 ,分析表明 ,固结比影响了砂土液化过程中的应力状态 ,从而造成在不同固结比情况下 ,砂土的应变、液化强度和孔隙水压力发展出现明显不同。固结比的不同会影响到砂土的液化应力状态 ,从而造成应变发展的不同 ,固结比为 1的实验受拉破坏先于受压破坏 ,对于其它的固结比 ,拉压破坏先后顺序与土的特性和孔隙水压力的发展有关。并且 ,由于固结比大的砂土在动荷载作用下易于达到剪胀 ,从而应力 应变曲线迅速向稳定形状过渡 ;随着固结比的增加 ,导致影响反向剪应力出现所需要的动应力也愈大 ,从而砂土液化强度会有所提高 ,但是 ,因固结比增加引起砂土强度的增加的趋势会受到动摩擦强度的限制 ;大固结比情况下的砂土进入剪胀较早 ,因而抑制了砂土残余孔隙压力的积累 ,影响了极限孔隙水压力的发展 ,研究表明 ,固结比愈大 。 展开更多
关键词 土力学 饱和砂土液化 固结比 孔隙水压力 影响分析 液化应变 液化强度 动三轴实验
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Numerical modelling rock deformation subject to nitrogen cooling to study permeability evolution 被引量:10
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作者 Chunhui Zhang Laigui Wang +1 位作者 Jianhua Du Yinghui Tian 《International Journal of Coal Science & Technology》 EI 2015年第4期293-298,共6页
How to model the permeability evolution of rock subjected to liquid nitrogen cooling is a key issue. This paper proposes a simple but practical method to study the permeability evolution of rocks subject to liquid nit... How to model the permeability evolution of rock subjected to liquid nitrogen cooling is a key issue. This paper proposes a simple but practical method to study the permeability evolution of rocks subject to liquid nitrogen cooling. FLAC with FISH function was employed to numerically model the rock behavior under cooling. The enhanced perme- ability of the volumetric strain was defined, and the permeability was directly evaluated based on element's volumetric strain. Detailed procedures for implementing the evolution model of permeability in this paper were presented. A case study was carried out to simulate a coal bed where liquid nitrogen was injected in the bore hole. And a semi-submerged test of liquid nitrogen was performed. The method to model the permeability evolution of rocks subject to liquid nitrogen shock in this paper was proved to be right by the test results. This simulation results are discussed with the hope to provide some insight into understanding the nitrogen cooling practice. 展开更多
关键词 Liquid nitrogen cooling Tension failure Temperature Permeability evolution Enhanced permeability
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Behaviour of large post-liquefaction deformation in saturated sand-gravel composites 被引量:3
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作者 潘华 陈国兴 +1 位作者 孙田 刘汉龙 《Journal of Central South University》 SCIE EI CAS 2012年第2期547-552,共6页
The laboratory tests on the post-liquefaction deformation of saturated sand-gravel composites were performed to investigate the characteristics of stress-strain relation and the dissipation of pore water pressure by t... The laboratory tests on the post-liquefaction deformation of saturated sand-gravel composites were performed to investigate the characteristics of stress-strain relation and the dissipation of pore water pressure by the hollow cylinder apparatus. It is found that the stress-strain response and the dissipation process of pore water pressure are composed of three stages, including the low intensive strength stage, the superlinear strength recovery stage and the sublinear strength recovery stage, and the demarcation points of the curve of pore water pressure are lag behind those of the stress-strain response. The comparison results of the behaviour of large post-liquefaction deformation between saturated sand-gravel composites and Nanjing fine sand show that the low intensive strength stage and the superlinear strength recovery stage of saturated sand-gravel composites are shorter while the sublinear strength recovery stage is longer. A stress-strain model and a dissipation model of excess pore water pressure of liquefied sand-gravel composites are established, in which the initial confining pressure and the relative density can be considered synthetically. And it is found that the predicted results by the two models are in good agreement with experimental data. 展开更多
关键词 saturated sand-gravel composites post-liquefaction deformation stress-strain relation dissipation model: pore water pressure
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镍基高温合金激光焊液化裂纹倾向性数值模拟研究
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作者 任闻杰 杨上陆 +2 位作者 孙军浩 陈双建 李铸国 《应用激光》 CSCD 北大核心 2024年第7期85-94,共10页
采用有限元计算方法对高温合金Inconel 617光纤激光焊和CO_(2)激光焊接热循环规律、热应力应变演变规律及其力学机制进行研究。结果表明,旋转体热源-旋转对数体热源-3D高斯热源模型构建的高温合金Inconel 617激光焊接热源模型准确性较好... 采用有限元计算方法对高温合金Inconel 617光纤激光焊和CO_(2)激光焊接热循环规律、热应力应变演变规律及其力学机制进行研究。结果表明,旋转体热源-旋转对数体热源-3D高斯热源模型构建的高温合金Inconel 617激光焊接热源模型准确性较好,热影响区的颈缩处冷却速率最低。当热影响区温度加热高于约1280℃,晶界和晶内开始发生组分液化。高温合金Inconel 617光纤激光焊和CO_(2)激光焊的Von miss应力均无大幅度的下降;光纤激光焊HAZ的第一主应变逐渐增加,而CO_(2)激光焊HAZ颈缩处附近的第一主应变增加明显。随着激光焊接热输入降低,HAZ液化裂纹敏感性应变速率逐渐增加。相对于激光焊接HAZ的von Mises应力和第一主应变,液化裂纹敏感性应变速率更适合解释Inconel 617高温合金激光焊接液化裂纹形成的主要因素。 展开更多
关键词 高温合金 激光焊接 应力应变 液化裂纹敏感性应变速率 液化裂纹
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Effects of Initial Static Shear Stress and Grain Shape on Liquefaction of Saturated Nanjing Sand
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作者 ZHUANG Haiyang PAN Shuxuan +1 位作者 LIU Qifei YU Xu 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第1期44-56,共13页
This paper mainly investigates the effects of initial static shear stress and grain shape on the liquefaction induced large deformation of saturated sand under torsional shear.Nanjing sand,mainly composed of platy gra... This paper mainly investigates the effects of initial static shear stress and grain shape on the liquefaction induced large deformation of saturated sand under torsional shear.Nanjing sand,mainly composed of platy grains,is tested with different initial static shear stress ratio(SSR)using a hollow column torsional shear apparatus.The tests find that the saturated Nanjing sand reaches full liquefaction under the superposition of initial static shear stress and cyclic stress for both stress reversal and non-reversal cases.However,it requires a large number of loading cycles to reach full liquefaction if stress reversal does not occur.With increasing the initial static stress,the large deformation of the Nanjing sand should mainly induced by the cyclic liquefaction firstly under a smaller initial shear stress,and then it should be induced by the residual deformation failure.The critical point occurs approximately when the initial shear stress is close to the amplitude of the cyclic shear stress.Meanwhile,it shows that grain angularity increases the liquefaction resistance when the initial static shear stress is zero.A small initial static shear stress causes the larger loss of liquefaction resistance for angular sand than rounded sand.At a high initial SSR,the angular sand is more resistant to the large residual deformation failure than the rounded sand. 展开更多
关键词 Nanjing sand LIQUEFACTION initial shear stress grain shape residual deformation failure
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Study and Application of New Polyamine Polymer Drilling Fluid
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作者 D. Ma L. Zhao +2 位作者 C. Ma M. Dong W.F. Yang 《Journal of Energy and Power Engineering》 2010年第10期23-28,共6页
Adding the polyamine inhibitor into drilling fluid can effectively strengthen the rejection capability and improve the rheological behavior of drilling fluid system. According to the analysis of the comparison of the ... Adding the polyamine inhibitor into drilling fluid can effectively strengthen the rejection capability and improve the rheological behavior of drilling fluid system. According to the analysis of the comparison of the physiochemical properties of the polyamine inhibitor, a polyamine polymer drilling fluid system was established by means of adding UAE polyamine into traditional polymer drilling fluid. Conventional properties and environmental influence of this system have been evaluated in this paper. The result indicates that the polymer drilling fluid system optimized by polyamine shows a high-performance, such as excellent rejection performance, better rheological and filtration properties, better environmental protection functions. Thus it can be used in high water-sensitive, high temperature, high pressure or vulnerable formation drilling operations. 展开更多
关键词 Polyamine polymer drilling fluid rejection capability anti-pollution capability rheological property environmental protection function.
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Theoretical solution for displacement and stress in strain-softening surrounding rock under hydraulic-mechanical coupling 被引量:12
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作者 ZOU JinFeng LI ShuaiShuai 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第8期1401-1413,共13页
This study focuses on the stress and displacement of a circular opening that is excavated in a strain-softening rock mass under hydraulic-mechanical coupling.It follows the generalized Hoek-Brown(H-B) failure criterio... This study focuses on the stress and displacement of a circular opening that is excavated in a strain-softening rock mass under hydraulic-mechanical coupling.It follows the generalized Hoek-Brown(H-B) failure criterion.Moreover,an improved numerical method and stepwise procedure are proposed.This method considers the deterioration of the strength,deformation,and dilation angle.It also incorporates the hydraulic-mechanical coupling and the variation of elastic strain in the plastic region.Several examples are conducted to demonstrate the validity and accuracy of the proposed solution through MATLAB programming and FLAC software.Parametric studies are also conducted to highlight the influence of hydraulic–mechanical coupling on stress and displacement.Results show that in this case,stress confinement is lower and tunnel convergences are higher than the corresponding stresses and displacements obtained when those factors are not considered.The displacement and plastic radius are also larger than those obtained when hydraulic-mechanical coupling is not considered. 展开更多
关键词 strain softening hydraulic-mechanical coupling numerical stepwise procedure circular opening
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The change in thickness of the solidified liquid layer rather than the immobilized mass determines the frequency response of a quartz crystal microbalance 被引量:1
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作者 HE JianAN LU YuDong +1 位作者 FANG Jing MA HongWei 《Science China Chemistry》 SCIE EI CAS 2012年第1期175-181,共7页
The "solidified liquid layer" model has been examined using a quartz crystal microbalance(QCM) with a polymeric matrix.The model is shown to give a reasonable explanation for the following experimental obser... The "solidified liquid layer" model has been examined using a quartz crystal microbalance(QCM) with a polymeric matrix.The model is shown to give a reasonable explanation for the following experimental observations:(i) The opposite response of the QCM and surface plasmon resonance(SPR) for the activation process;(ii) the marked difference in the responses for IgG/anti-IgG interaction between QCM and SPR.Theoretical analysis and experimental results indicated that QCM is sensitive to the thickness change of the "solidified liquid layer" but not the mass of captured biomolecules(i.e.,the immobilized mass),implying caution must be taken in interpreting QCM results. 展开更多
关键词 quartz crystal microbalance solidified liquid layer matrix BIOSENSOR
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