This paper analyzes the observing results of vacuum degree in the the Jialichen bridge-head experimental site .The cause of vacuum degree developing below groundwater table is pointed out. The influence of vacuum degr...This paper analyzes the observing results of vacuum degree in the the Jialichen bridge-head experimental site .The cause of vacuum degree developing below groundwater table is pointed out. The influence of vacuum degree above the ground water table on pore water pressure is discussed. The results show that vacuum degree decreases along the depth because resistance. The resistance in the PVDS is lowest, in the silt is highest. Vacuum degree below groundwater table is produced mainly by dewatering or by escaping of sealed air from the end of flexible pipe. Vacuum degree above the ground water table in the sand drains makes great effect on pore water pressure. In the silt the pore water pressure does not change with the variation of vacuum degree under membrane in a short time.展开更多
The stability of railway subgrade in permafrost regions is crucial to the safety of railway operation. In thispaper, we firstanalyze the main factors influencing the stabilityof frozen subgrade. Then, we build an expe...The stability of railway subgrade in permafrost regions is crucial to the safety of railway operation. In thispaper, we firstanalyze the main factors influencing the stabilityof frozen subgrade. Then, we build an experimental equipment in which regulation-tubes are arranged axiallyin subgrade and arranged slantwaysat the foot of slopes,and make the model experiments on maintaining the stability of frozen subgrade by collecting-controlling cold energy.The experiments includetwo groups. One is maintaining the stability by collecting-controllingnatural cold energyin winter, and another is maintaining the stability by collecting-controllingnatural cold energyin winter and artificial cold energyin summer.Finally, we obtain the behavior of temperature fields in the subgrade during the experiments, which establishes basis for further study on the subgrade stability and on the feasibility of rushing to deal with freezing damageof frozen subgrade.展开更多
文摘This paper analyzes the observing results of vacuum degree in the the Jialichen bridge-head experimental site .The cause of vacuum degree developing below groundwater table is pointed out. The influence of vacuum degree above the ground water table on pore water pressure is discussed. The results show that vacuum degree decreases along the depth because resistance. The resistance in the PVDS is lowest, in the silt is highest. Vacuum degree below groundwater table is produced mainly by dewatering or by escaping of sealed air from the end of flexible pipe. Vacuum degree above the ground water table in the sand drains makes great effect on pore water pressure. In the silt the pore water pressure does not change with the variation of vacuum degree under membrane in a short time.
文摘The stability of railway subgrade in permafrost regions is crucial to the safety of railway operation. In thispaper, we firstanalyze the main factors influencing the stabilityof frozen subgrade. Then, we build an experimental equipment in which regulation-tubes are arranged axiallyin subgrade and arranged slantwaysat the foot of slopes,and make the model experiments on maintaining the stability of frozen subgrade by collecting-controlling cold energy.The experiments includetwo groups. One is maintaining the stability by collecting-controllingnatural cold energyin winter, and another is maintaining the stability by collecting-controllingnatural cold energyin winter and artificial cold energyin summer.Finally, we obtain the behavior of temperature fields in the subgrade during the experiments, which establishes basis for further study on the subgrade stability and on the feasibility of rushing to deal with freezing damageof frozen subgrade.
