Experimental Study On Resistivity And Strength Characteristics Of Cement-cured Soil Under Freeze-thaw Cycle

With the continuous development of the country,the resources of many cold regions are slowly developing,and a large number of engineering projects are also planned in cold regions.Therefore,we need more research on the frozen soil and its physical properties in cold regions.Deepen understanding and rational use.This paper adopts the representative seasonal frozen soil on the G318 national highway of Sichuan-Tibet line as the research object.On the basis of fully drawing on and drawing on the research results of the predecessors,the indoor geotechnical test,resistivity test,freeze-thaw cycle test,unconfined compressive strength test,direct shear test,etc.,systematically studied the unconfined compressive strength,shear strength index(cohesion,internal friction angle)and electrical resistivity of cement solidified soil under freeze-thaw cycles.The variation of the three factors including the amount of cement incorporation,the number of freeze-thaw cycles and the water content.At the same time,the relationship between the unconfined compressive strength,the shear strength index(cohesion,internal friction angle)and the resistivity of the solidified soil is discussed.The research content and conclusions obtained in this paper mainly include the following aspects:(1)The variation of the characteristics of unconfined compressive strength by three factors:freeze-thaw cycle number,cement admixture and water content.(1)When cement is added to the soil,the number of freeze-thaw cycles can increase the unconfined compressive strength of the soil.(2)When the water content is high,the freeze-thaw cycle causes the unconfined compressive strength loss of the plain soil to be relatively low and the water content is high.(3)When the water content is low,the freeze-thaw cycle causes the unconfined compressive strength of the cement soil to increase compared to the high water content.(2)The three factors of freeze-thaw cycle,cement admixture and water content resist the change of shear strength index characteristics.(1)When the amount of cement is low,the freeze-thaw cycle can increase the cohesive force of the solidified soil,and the internal friction angle decreases.The high cement admixture can reduce the cohesive force and freeze-thaw cycle.The more the cohesive force loss of the solidified soil under the action,the smaller the internal friction angle loss.(2)When the water content is high,the freeze-thaw cycle leads to a higher cohesion of the plain soil than the low water content,while the internal friction angle decreases.When the water content is moderate,the freeze-thaw cycle causes the cohesive force loss of the cement soil to be larger than that of the high water content or the low water content.When the water content is low,the freeze-thaw cycle causes the internal friction angle loss of the cement soil to be larger than that of the high water content.(3)With the increase of freeze-thaw cycles,the cohesive force of both plain soil and solidified soil increases gradually and then stabilizes,and the growth tendency of solidified soil is less than that of plain soil.(3)The variation of the characteristics of resistivity by the three factors of freezing and thawing cycles,cement incorporation and water content.(1)When the high cement blending amount,the resistivity of the cement solidified soil increases.(2)At different moisture contents,the resistivity of the plain soil is relatively high under unfrozen conditions.(3)When the number of freeze-thaw cycles is too high,the resistivity has a relatively stable state.When the number of freeze-thaw cycles is small,the resistivity is unstable.(4)In the unfrozen and fused state,the resistivity of the cemented soil with different content is nonlinearly correlated with the unconfined compressive strength,cohesive force and internal friction angle,linear correlation and nonlinear correlation.Under different freezing and thawing conditions,the resistivity of the cemented soil with different contents is linearly correlated with the unconfined compressive strength,cohesive force and internal friction angle,nonlinear correlation and linear correlation.