This paper describes new building construction methods that utilize soil thermal stabilization reghnes to compensate for negative environmental wanning and anthropogenic factors that impair fundament stability. Based ...This paper describes new building construction methods that utilize soil thermal stabilization reghnes to compensate for negative environmental wanning and anthropogenic factors that impair fundament stability. Based on long-standing research, the Funda- mentstroyarkos Company （FSA） of Tyumen, Russia has developed four primary seasonally active cooling devices （SCDs） that maintain soil in the frozen state, which are now extensively used on oil and gas facilities located in cold regions of Russia. This paper reports on the testing and validation of these SCDs in experimental conditions. On this basis, desigqls and technologies for building bases and foundations on permafrost with use of soil thermal stabilization systems, using carbon dioxide as the heat-transfer agent, were developed.展开更多
This paper aims to determine the optimal fines content of coarse-grained soil required to simultaneously achieve weaker frost susceptibility and better bearing capacity. We studied the frost susceptibility and strengt...This paper aims to determine the optimal fines content of coarse-grained soil required to simultaneously achieve weaker frost susceptibility and better bearing capacity. We studied the frost susceptibility and strength properties of coarse-grained soil by means of frost heaving tests and static triaxial tests, and the results are as follows： （1） the freezing temperature of coarse-grained soil decreased gradually and then leveled off with incremental increases in the percent content of fines; （2） the fines content proved to be an important factor influencing the frost heave susceptibility and strength properties of coarse-grained soil. With incremental increases in the percent content of fines, the frost heave ratio increased gradually and the cohesion function of fines effectively enhanced the shear strength of coarse-grained soil before freeze-thaw, but the frost susceptibility of fines weakened the shear strength of coarse-grained soil after freeze-thaw; （3） with increasing numbers of freeze-thaw cycles, the shear strength of coarse-grained soil decreased and then stabilized after the ninth freeze-thaw cycle, and therefore the mechanical indexes of the ninth freeze-thaw cycle are recommended for the engi- neering design values; and （4） considering frost susceptibility and strength properties as a whole, the optimal fines content of 5% is recommended for railway sub,fade coarse-~rained soil fillings in frozen re^ions.展开更多
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
文摘This paper describes new building construction methods that utilize soil thermal stabilization reghnes to compensate for negative environmental wanning and anthropogenic factors that impair fundament stability. Based on long-standing research, the Funda- mentstroyarkos Company （FSA） of Tyumen, Russia has developed four primary seasonally active cooling devices （SCDs） that maintain soil in the frozen state, which are now extensively used on oil and gas facilities located in cold regions of Russia. This paper reports on the testing and validation of these SCDs in experimental conditions. On this basis, desigqls and technologies for building bases and foundations on permafrost with use of soil thermal stabilization systems, using carbon dioxide as the heat-transfer agent, were developed.
基金supported by the National Key Technology Support Program of China (No.2012BAG05B00)the National Natural Science Foundation of China (Nos. 51208320 and 51178281)the Key Subject of China Railway Corporation (Nos. 2014G003-F and 2014G003-A)
文摘This paper aims to determine the optimal fines content of coarse-grained soil required to simultaneously achieve weaker frost susceptibility and better bearing capacity. We studied the frost susceptibility and strength properties of coarse-grained soil by means of frost heaving tests and static triaxial tests, and the results are as follows： （1） the freezing temperature of coarse-grained soil decreased gradually and then leveled off with incremental increases in the percent content of fines; （2） the fines content proved to be an important factor influencing the frost heave susceptibility and strength properties of coarse-grained soil. With incremental increases in the percent content of fines, the frost heave ratio increased gradually and the cohesion function of fines effectively enhanced the shear strength of coarse-grained soil before freeze-thaw, but the frost susceptibility of fines weakened the shear strength of coarse-grained soil after freeze-thaw; （3） with increasing numbers of freeze-thaw cycles, the shear strength of coarse-grained soil decreased and then stabilized after the ninth freeze-thaw cycle, and therefore the mechanical indexes of the ninth freeze-thaw cycle are recommended for the engi- neering design values; and （4） considering frost susceptibility and strength properties as a whole, the optimal fines content of 5% is recommended for railway sub,fade coarse-~rained soil fillings in frozen re^ions.
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.
