Fine round gravel soil is widely employed in the subgrade of high and thawing. The lower the fines content in fine round gravel soil, but compaction difficulty increases. This study is to obtain the speed railways in ...Fine round gravel soil is widely employed in the subgrade of high and thawing. The lower the fines content in fine round gravel soil, but compaction difficulty increases. This study is to obtain the speed railways in cold regions to prevent frost heaving the smaller the quantities of frost heaving and thawing, optimum fines content and limited frost heaving and thawing. The fine round gravel soil filling （FRGSF） used in the Harbin-Qiqihaer Passenger Dedicated Line is taken as the study object. Influence of fines content on optimum water content, maximum dry density and frost heaving properties of FRGSF were studied by means of compaction and frost heaving tests. Results show that the maximum dry density of the FRGSF increases first and then decreases with an increase of fines content, namely there is an optimum fines content for easy compaction. The method of surface-vibratory instrument is fit for coarse-grained soils, and wet state of coarse-grained soil is in favor of compaction. Considering the relationship of fines content with maximum dry density and the frost heaving ratio of FRGSF, the fines content should be limited to within the range of 9%-10%, so that the frost heaving ratio is less than 1%, and the FRGSF is easily compacted. Water supply is proved to be an important factor influencing the amount of frost heaving of FRGSF. We also conclude that in the field, it is imperative to control waterproofing and drainage measures.展开更多
Frost heave is one of the major complications in highway construction in cold regions. Laboratory experiments are im- portant in the study frost heave behavior of soils, and one-dimensional frost heave experiments are...Frost heave is one of the major complications in highway construction in cold regions. Laboratory experiments are im- portant in the study frost heave behavior of soils, and one-dimensional frost heave experiments are the easiest way to evaluate the soil frost heave potential. In a one dimensional frost heave test, the deformation in axial direction is non-uniform because of the confining effect of the cutting ring＇s sidewall. If the effect of confining boundary on soil de- formation is ignored, the deformation will be over-estimated. In this paper, the effect of confining boundary on soil de- formation is theoretically studied and a volume correction method is developed and applied to the frost heave test of a sulfite saline soil. Test results demonstrate that the sulfite saline soil will expand to a loose, low-density state after several freezing-thawing cycles under the condition of zero axial stress.展开更多
Frost heave in seasonally frozen regions is a one-dimensional process that could severely damage infrastructure subgrades.Stress state,temperature and water migration are important factors for frost heave.This work in...Frost heave in seasonally frozen regions is a one-dimensional process that could severely damage infrastructure subgrades.Stress state,temperature and water migration are important factors for frost heave.This work investigated the effects of soil temperature and volumetric water content on the transient frost heave ratio during the freezing of saturated silty clay in an open system and analyzed the relationships between the transient frost heave ratio and freezing rate and between temperature gradient and frost heave rate.The results show that the frost heave ratio,frost heave rate,and freezing rate are positively correlated with the temperature gradient since the temperature gradient drives the water migration during freezing,indicating the transient temperature gradient could be used to evaluate the frost heave of saturated silty clay.The transient freezing rate and transient frost heave ratio are logarithmically related to the transient frost heave ratio and transient temperature gradient,respectively.The effects of transient temperature gradient on frost heave are the principal mechanism responsible for different frost heave characteristics and uneven frost heave along a subgrade of the same soil type.展开更多
After analysing the results of systematic experimental research on frost susceptibility tests, a new frost heave prediction model, including the heave ratio η and rate R, is first proposed in this paper. Six main fac...After analysing the results of systematic experimental research on frost susceptibility tests, a new frost heave prediction model, including the heave ratio η and rate R, is first proposed in this paper. Six main factors influencing frost heave are considered: initial water content W, initial dry unit weight γd, frost penetration rate Vf, groundwater level Hw, plasticity index Ip and ion content S. The model could be expressed by: η= B0WB1γBd2VB31·exp(B4Hw)exp(B5Ip)exp(B6S) and R = B’0WB’1γB’2dexp(B’3Hw)exp(B’4Ip)exp(B’5S) with a good reliability, where B0 to B6 and B’0 to B’5 are the characteristic constants of clayey soils. The effect of each factor on frost susceptibility of soils is discussed also.展开更多
基金funded by the National Key Technology Support Program of China under Grant No. 2012BAG05B00the National Natural Science Foundation (NSFC) of China under Grant No. 51208320 and No. 51171281
文摘Fine round gravel soil is widely employed in the subgrade of high and thawing. The lower the fines content in fine round gravel soil, but compaction difficulty increases. This study is to obtain the speed railways in cold regions to prevent frost heaving the smaller the quantities of frost heaving and thawing, optimum fines content and limited frost heaving and thawing. The fine round gravel soil filling （FRGSF） used in the Harbin-Qiqihaer Passenger Dedicated Line is taken as the study object. Influence of fines content on optimum water content, maximum dry density and frost heaving properties of FRGSF were studied by means of compaction and frost heaving tests. Results show that the maximum dry density of the FRGSF increases first and then decreases with an increase of fines content, namely there is an optimum fines content for easy compaction. The method of surface-vibratory instrument is fit for coarse-grained soils, and wet state of coarse-grained soil is in favor of compaction. Considering the relationship of fines content with maximum dry density and the frost heaving ratio of FRGSF, the fines content should be limited to within the range of 9%-10%, so that the frost heaving ratio is less than 1%, and the FRGSF is easily compacted. Water supply is proved to be an important factor influencing the amount of frost heaving of FRGSF. We also conclude that in the field, it is imperative to control waterproofing and drainage measures.
基金supported by the State Key Development Program of Basic Research of China (Project No.2012CB026104)a Chinese National Key Technology R&D Program of the Ministry of Science and Technology Project(2012BAH10B01)an open fund sponsored by Qinghai Research and Observation Base, Key Laboratory of Highway Construction & Maintenance Technologyin Permafrost Regions, Ministry of Transport
文摘Frost heave is one of the major complications in highway construction in cold regions. Laboratory experiments are im- portant in the study frost heave behavior of soils, and one-dimensional frost heave experiments are the easiest way to evaluate the soil frost heave potential. In a one dimensional frost heave test, the deformation in axial direction is non-uniform because of the confining effect of the cutting ring＇s sidewall. If the effect of confining boundary on soil de- formation is ignored, the deformation will be over-estimated. In this paper, the effect of confining boundary on soil de- formation is theoretically studied and a volume correction method is developed and applied to the frost heave test of a sulfite saline soil. Test results demonstrate that the sulfite saline soil will expand to a loose, low-density state after several freezing-thawing cycles under the condition of zero axial stress.
基金supported by the National Natural Science Foundation of China(No.51808128)the Natural Science Foundation of Fujian Province(No.2022J01091)。
文摘Frost heave in seasonally frozen regions is a one-dimensional process that could severely damage infrastructure subgrades.Stress state,temperature and water migration are important factors for frost heave.This work investigated the effects of soil temperature and volumetric water content on the transient frost heave ratio during the freezing of saturated silty clay in an open system and analyzed the relationships between the transient frost heave ratio and freezing rate and between temperature gradient and frost heave rate.The results show that the frost heave ratio,frost heave rate,and freezing rate are positively correlated with the temperature gradient since the temperature gradient drives the water migration during freezing,indicating the transient temperature gradient could be used to evaluate the frost heave of saturated silty clay.The transient freezing rate and transient frost heave ratio are logarithmically related to the transient frost heave ratio and transient temperature gradient,respectively.The effects of transient temperature gradient on frost heave are the principal mechanism responsible for different frost heave characteristics and uneven frost heave along a subgrade of the same soil type.
基金Project supported by the National Natural Science Foundation of China.
文摘After analysing the results of systematic experimental research on frost susceptibility tests, a new frost heave prediction model, including the heave ratio η and rate R, is first proposed in this paper. Six main factors influencing frost heave are considered: initial water content W, initial dry unit weight γd, frost penetration rate Vf, groundwater level Hw, plasticity index Ip and ion content S. The model could be expressed by: η= B0WB1γBd2VB31·exp(B4Hw)exp(B5Ip)exp(B6S) and R = B’0WB’1γB’2dexp(B’3Hw)exp(B’4Ip)exp(B’5S) with a good reliability, where B0 to B6 and B’0 to B’5 are the characteristic constants of clayey soils. The effect of each factor on frost susceptibility of soils is discussed also.
