The observations on compressibility of reconstituted clays show that the compression line with a higher initial water content lies above the compression line with a lower initial water content for a given clay. Hence ...The observations on compressibility of reconstituted clays show that the compression line with a higher initial water content lies above the compression line with a lower initial water content for a given clay. Hence there exists additional void ratio due to initial water contents among virgin compression lines（VCLs） of reconstituted clays. In this paper, the difference in void ratio caused by different initial water contents is investigated based on the empirical equation proposed by Liu and Carter（2000） for describing the differential void ratio at the same stress between natural and reconstituted clays. The mechanism of compressibility of reconstituted clays, when the stress level is larger than the remolded yield stress, is also discussed.展开更多
The tunnel-train-air interaction problem is investigated by using a numerical method able to provide relevant information about pressure fluctuations,aerodynamic drag characteristics and the“piston wind”effect.The m...The tunnel-train-air interaction problem is investigated by using a numerical method able to provide relevant information about pressure fluctuations,aerodynamic drag characteristics and the“piston wind”effect.The method relies on a RNG k-εtwo-equation turbulence model.It is shown that although reducing the oblique slope can alleviate the pressure gradient resulting from initial compression waves at the tunnel entrance,the pressure fluctuations in the tunnel are barely affected;however,a large reduction of micro-pressure wave amplitudes is found outside the tunnel.In comparison to the case where no tunnel hood is present,the amplitudes of micro-pressure waves at 40 m from the tunnel reach an acceptable range.The aerodynamic drag of the head and tail fluctuates greatly while that of the intermediate region undergoes only limited variations when the high-speed train passes through the double-hat oblique tunnel.It is shown that the effects of the oblique slope of the portal on the aerodynamic drag can almost be ignored while the train speed plays an important role.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41502263,41372309 and 41330641)the National Key Basic Research Program of China(973 Program,Grant No.2015CB057803)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20150819)the Fundamental Research Funds for the Central Universities of China in support of this study is also gratefully acknowledged
文摘The observations on compressibility of reconstituted clays show that the compression line with a higher initial water content lies above the compression line with a lower initial water content for a given clay. Hence there exists additional void ratio due to initial water contents among virgin compression lines（VCLs） of reconstituted clays. In this paper, the difference in void ratio caused by different initial water contents is investigated based on the empirical equation proposed by Liu and Carter（2000） for describing the differential void ratio at the same stress between natural and reconstituted clays. The mechanism of compressibility of reconstituted clays, when the stress level is larger than the remolded yield stress, is also discussed.
基金supported by the National Natural Science Foundation of China,China Grant(11972028),under the project“Analysis of Unsteady Aerodynamic Characteristics of High-Speed Train”。
文摘The tunnel-train-air interaction problem is investigated by using a numerical method able to provide relevant information about pressure fluctuations,aerodynamic drag characteristics and the“piston wind”effect.The method relies on a RNG k-εtwo-equation turbulence model.It is shown that although reducing the oblique slope can alleviate the pressure gradient resulting from initial compression waves at the tunnel entrance,the pressure fluctuations in the tunnel are barely affected;however,a large reduction of micro-pressure wave amplitudes is found outside the tunnel.In comparison to the case where no tunnel hood is present,the amplitudes of micro-pressure waves at 40 m from the tunnel reach an acceptable range.The aerodynamic drag of the head and tail fluctuates greatly while that of the intermediate region undergoes only limited variations when the high-speed train passes through the double-hat oblique tunnel.It is shown that the effects of the oblique slope of the portal on the aerodynamic drag can almost be ignored while the train speed plays an important role.
