The field tests were carried out to examine the reinforcement effect of a geogrid on various conditions of embankment height,the number of passages of vibratory roller,the number of reinforced layer of geogrid,and soi...The field tests were carried out to examine the reinforcement effect of a geogrid on various conditions of embankment height,the number of passages of vibratory roller,the number of reinforced layer of geogrid,and soil properties.The test results of the dynamic earth pressure indicate that the soil reinforced by geogrid is very effective to increase the stiffness of soil,especially in soft soil.The dynamic earth pressure ratio,which is defined as the ratio of dynamic earth pressure to self weight of soils,exponentially decreases as the embankment height increases.The dynamic earth pressure ratio increases up to 80% for soft soils reinforced by both one layer of geogrid in place of no reinforced soils and two layers in place of a single layer of geogrid.展开更多
An experimental study and theoretical analysis were carried out to explore the ground-borne vibration generated by elevated high-speed railway in rock strata.Taking a typical rail line constructed on rock area in Chin...An experimental study and theoretical analysis were carried out to explore the ground-borne vibration generated by elevated high-speed railway in rock strata.Taking a typical rail line constructed on rock area in China as the research object,a set of field tests was performed on Rizhao-Lankao High-Speed Railway,the bridge and ground vibrations were measured as trains passed at 330−340 km/h,then the transferring law and spatial distribution under individual frequencies were investigated.The experiment results indicate that the bridge frequency spectrum exhibited relatively high-frequency vibration peaks caused by short-wavelength irregularity;ground vibration farther than 30 m away can be amplified with a higher frequency and numerous components.Furthermore,the wave propagation equation of a stratified rock strata was established based on direct-stiffness method to explore the vibration attenuation rules via frequency-domain analysis.It is found that the rock area has a weaker correlation between vibration transmissibility and frequency,thicker and harder rock strata loss their vibration attenuation capacity.It can be concluded that the high-speed railways induced vibration on rock strata shows a wide frequency band and large amplitude,the design of reducing vibration aimed at specific frequency is important according to next more detailed numerical study.展开更多
文摘The field tests were carried out to examine the reinforcement effect of a geogrid on various conditions of embankment height,the number of passages of vibratory roller,the number of reinforced layer of geogrid,and soil properties.The test results of the dynamic earth pressure indicate that the soil reinforced by geogrid is very effective to increase the stiffness of soil,especially in soft soil.The dynamic earth pressure ratio,which is defined as the ratio of dynamic earth pressure to self weight of soils,exponentially decreases as the embankment height increases.The dynamic earth pressure ratio increases up to 80% for soft soils reinforced by both one layer of geogrid in place of no reinforced soils and two layers in place of a single layer of geogrid.
基金Project(2016YFE0205200)supported by the National Key Research and Development Program of ChinaProjects(U1734207,51978585)supported by the National Natural Science Foundation of China。
文摘An experimental study and theoretical analysis were carried out to explore the ground-borne vibration generated by elevated high-speed railway in rock strata.Taking a typical rail line constructed on rock area in China as the research object,a set of field tests was performed on Rizhao-Lankao High-Speed Railway,the bridge and ground vibrations were measured as trains passed at 330−340 km/h,then the transferring law and spatial distribution under individual frequencies were investigated.The experiment results indicate that the bridge frequency spectrum exhibited relatively high-frequency vibration peaks caused by short-wavelength irregularity;ground vibration farther than 30 m away can be amplified with a higher frequency and numerous components.Furthermore,the wave propagation equation of a stratified rock strata was established based on direct-stiffness method to explore the vibration attenuation rules via frequency-domain analysis.It is found that the rock area has a weaker correlation between vibration transmissibility and frequency,thicker and harder rock strata loss their vibration attenuation capacity.It can be concluded that the high-speed railways induced vibration on rock strata shows a wide frequency band and large amplitude,the design of reducing vibration aimed at specific frequency is important according to next more detailed numerical study.
