Determination of the critical state line(CSL)is important to characterize engineering properties of granular soils.Grain size distribution(GSD)has a significant influence on the location of CSL.The influence of partic...Determination of the critical state line(CSL)is important to characterize engineering properties of granular soils.Grain size distribution(GSD)has a significant influence on the location of CSL.The influence of particle breakage on the CSL is mainly attributed to the change in GSD due to particle breakage.However,GSD has not been properly considered in modeling the CSL with influence of particle breakage.This study aims to propose a quantitative model to determine the CSL considering the effect of GSD.We hypothesize that the change of critical state void ratio with respect to GSD is caused by the same mechanism that influences of the change of minimum void ratio with respect to GSD.Consequently,the particle packing model for minimum void ratio proposed by Chang et al.(2017)is extended to predict critical state void ratio.The developed model is validated by experimental results of CSLs for several types of granular materials.Then the evolution of GSD due to particle breakage is incorporated into the model.The model is further evaluated using the experimental results on rockfill material,which illustrates the applicability of the model in predicting CSL for granular material with particle breakage.展开更多
Extensive oedometer tests and physical tests have been conducted on remolded and reconstituted marine soils with different initial water contents and liquid limits. The oedometer test data can be well fitted with a st...Extensive oedometer tests and physical tests have been conducted on remolded and reconstituted marine soils with different initial water contents and liquid limits. The oedometer test data can be well fitted with a straight line in the bilogarithmic ln(1+ e ) ～ lg p plot. The initial effective stress corresponding to the initial void ratio is determined by extrapolation of the bilogarithmic compression line. This new way of extrapolating oedometer test data to the initial void ratio overcomes the difficulty of measuring the residual effective stress of soils in the remolded state. The initial stable compression line of ocean floor deposits under different deposition environments corresponds to the compression line at the sensitivity equal to one. This initial stable compression line obtained in this study is consistent with the available compression line at the sensitivity equal to one which is proposed based on the experimental data of remolded undrained strength and the theoretical concept of Cam clay critical state line.展开更多
In this paper, numerical simulation of shock-induced chemical reactions of intermetallic mixtures is discussed. Specifically, the paper focuses on intermetallic mixture of nickel and aluminum. To initiate the chemical...In this paper, numerical simulation of shock-induced chemical reactions of intermetallic mixtures is discussed. Specifically, the paper focuses on intermetallic mixture of nickel and aluminum. To initiate the chemical reactions, the thermal input or the shockwave should supply the energy to take the reactants, mixture of nickel and aluminum, to the transition state. Thus, for any numerical simulation or analysis of the shock or thermally induced chemical reaction in a continuum scale or a meso scale, it is necessary to identify the transition state. The transition state for the intermetallic mixture of nickel and the aluminum is identified in this paper and a result of the numerical simulation of the shock-induced chemical reaction, in a continuum scale is presented. The numerical solutions clearly show the chemical reactions, release of heat energy, increase of the temperature and the formation of products, following the transition state and the resulting shock-induced chemical reaction of a binary intermetallic energetic mixture of nickel and aluminum. The studies also show that the collapse of porosity is a mechanism that takes the reactants to the transition state, in shock-induced chemical reactions of binary intermetallic mixtures.展开更多
有研究结果表明,孔隙比是影响土–水特征曲线(SWCC)的直接因素,而应力状态是通过孔隙比影响SWCC的间接因素。然而相关文献中关于孔隙比对SWCC影响的试验研究,一般只控制了试样的初始孔隙比相同或者不同,而在SWCC试验过程中对试样的孔隙...有研究结果表明,孔隙比是影响土–水特征曲线(SWCC)的直接因素,而应力状态是通过孔隙比影响SWCC的间接因素。然而相关文献中关于孔隙比对SWCC影响的试验研究,一般只控制了试样的初始孔隙比相同或者不同,而在SWCC试验过程中对试样的孔隙比并没有加以控制。为了深化对孔隙比和应力状态对SWCC影响的认识,以山东东营黏土为研究对象,采用应力相关土水特征曲线仪,对试样沿预定路径进行单向压缩或单向压缩–回弹以后,控制竖向应力或孔隙比在脱—吸湿SWCC试验过程中保持不变。结果表明:在本次吸力范围内(未超过400 k Pa)的脱湿—吸湿过程中,即使竖向应力相同(等应力状态),只要孔隙比不同,则SWCC就不同;但只要保持试验过程中试样孔隙比不变(等孔隙比状态),则竖向应力的变化对SWCC几乎没有影响。等孔隙比状态下,即使竖向应力不同,但试样的进气值相近,脱/吸湿速率也几乎保持一致;等应力状态下,进气值随着孔隙比的增大而减小,脱—吸湿SWCC的滞回度和滞回圈面积随孔隙比增加而增大。研究结果对于建立SWCC模型时,如何选取模型参数具有理论指导意义。展开更多
基金supported by the National Science Foundation of the United States under a research grant (CMMI-1917238)
文摘Determination of the critical state line(CSL)is important to characterize engineering properties of granular soils.Grain size distribution(GSD)has a significant influence on the location of CSL.The influence of particle breakage on the CSL is mainly attributed to the change in GSD due to particle breakage.However,GSD has not been properly considered in modeling the CSL with influence of particle breakage.This study aims to propose a quantitative model to determine the CSL considering the effect of GSD.We hypothesize that the change of critical state void ratio with respect to GSD is caused by the same mechanism that influences of the change of minimum void ratio with respect to GSD.Consequently,the particle packing model for minimum void ratio proposed by Chang et al.(2017)is extended to predict critical state void ratio.The developed model is validated by experimental results of CSLs for several types of granular materials.Then the evolution of GSD due to particle breakage is incorporated into the model.The model is further evaluated using the experimental results on rockfill material,which illustrates the applicability of the model in predicting CSL for granular material with particle breakage.
文摘Extensive oedometer tests and physical tests have been conducted on remolded and reconstituted marine soils with different initial water contents and liquid limits. The oedometer test data can be well fitted with a straight line in the bilogarithmic ln(1+ e ) ～ lg p plot. The initial effective stress corresponding to the initial void ratio is determined by extrapolation of the bilogarithmic compression line. This new way of extrapolating oedometer test data to the initial void ratio overcomes the difficulty of measuring the residual effective stress of soils in the remolded state. The initial stable compression line of ocean floor deposits under different deposition environments corresponds to the compression line at the sensitivity equal to one. This initial stable compression line obtained in this study is consistent with the available compression line at the sensitivity equal to one which is proposed based on the experimental data of remolded undrained strength and the theoretical concept of Cam clay critical state line.
文摘In this paper, numerical simulation of shock-induced chemical reactions of intermetallic mixtures is discussed. Specifically, the paper focuses on intermetallic mixture of nickel and aluminum. To initiate the chemical reactions, the thermal input or the shockwave should supply the energy to take the reactants, mixture of nickel and aluminum, to the transition state. Thus, for any numerical simulation or analysis of the shock or thermally induced chemical reaction in a continuum scale or a meso scale, it is necessary to identify the transition state. The transition state for the intermetallic mixture of nickel and the aluminum is identified in this paper and a result of the numerical simulation of the shock-induced chemical reaction, in a continuum scale is presented. The numerical solutions clearly show the chemical reactions, release of heat energy, increase of the temperature and the formation of products, following the transition state and the resulting shock-induced chemical reaction of a binary intermetallic energetic mixture of nickel and aluminum. The studies also show that the collapse of porosity is a mechanism that takes the reactants to the transition state, in shock-induced chemical reactions of binary intermetallic mixtures.
文摘有研究结果表明,孔隙比是影响土–水特征曲线(SWCC)的直接因素,而应力状态是通过孔隙比影响SWCC的间接因素。然而相关文献中关于孔隙比对SWCC影响的试验研究,一般只控制了试样的初始孔隙比相同或者不同,而在SWCC试验过程中对试样的孔隙比并没有加以控制。为了深化对孔隙比和应力状态对SWCC影响的认识,以山东东营黏土为研究对象,采用应力相关土水特征曲线仪,对试样沿预定路径进行单向压缩或单向压缩–回弹以后,控制竖向应力或孔隙比在脱—吸湿SWCC试验过程中保持不变。结果表明:在本次吸力范围内(未超过400 k Pa)的脱湿—吸湿过程中,即使竖向应力相同(等应力状态),只要孔隙比不同,则SWCC就不同;但只要保持试验过程中试样孔隙比不变(等孔隙比状态),则竖向应力的变化对SWCC几乎没有影响。等孔隙比状态下,即使竖向应力不同,但试样的进气值相近,脱/吸湿速率也几乎保持一致;等应力状态下,进气值随着孔隙比的增大而减小,脱—吸湿SWCC的滞回度和滞回圈面积随孔隙比增加而增大。研究结果对于建立SWCC模型时,如何选取模型参数具有理论指导意义。
