Engineering Mechanical Properties Of Saline Soil And Rice Husk Ash Solidified Saline Soil Under Freeze-thaw Cycles

In recent years,the area and degree of saline soil in our country have been increasing.Especially in the northwest region,the degree of land salinization is even worse.The existence of saline soil not only hinders the development of agriculture,but also hinders the construction of infrastructure and the development of the construction industry.Therefore,it is very urgent to carry out research on the improvement of saline soil.Southeast Asian countries,which are large rice husk producers,use the rice husk ash produced by the burning of rice husks as roadbed fillers to enhance the bearing capacity of the soil.As a major rice-producing country,China has abundant rice husk resources,but its utilization rate is relatively low.Therefore,this topic chose to use rice husk ash to solidify and improve the saline soil,and to study the changes in the engineering properties of saline soil before and after solidification of rice husk ash.In this paper,the indoor artificially prepared chlorine saline soil is taken as the research object.First,the basic physical properties of the soil are measured,and then the changes of the physical and mechanical indexes and compression characteristics of the saline soil with the soil water content,salt content,and the number of freeze-thaw cycles are studied.Combining with the improvement of saline soil,the experimental scheme of using rice husk ash to strengthen saline soil is proposed.In the experiment,the mechanical properties and compression deformation characteristics of rice husk ash modified soil were analyzed with the rice husk ash content,curing age and the number of freeze-thaw cycles,and the mechanism of soil engineering properties was explained.In addition,referring to the research results of other scholars,the cohesion and compressive strength models of saline soil and improved soil were established.It provides a theoretical basis for further study on the engineering properties of saline soil and the application of rice husk ash in practical engineering.The main conclusions are as follows:(1)The optimal water content of saline soil gradually decreases with increase salt content,and the maximum dry density gradually increases with increase salt content;the optimal moisture content of the solidified soil of rice husk ash gradually increases with the increase of the rice husk ash content,and the maximum dry density gradually decreases with the increase of the rice husk ash content.(2)With the increase of water content and freezing and thawing times,the shear strength index and compressive strength of saline soil generally decreased to varying degrees,but the compressibility showed a trend of becoming larger.As the salt content increases,its shear strength index and compressive strength show a trend of decreasing first and then increasing,but overall,the fluctuation range is small.But its compression characteristics increase with the increase of salt content,the change trend is more obvious.(3)The mechanical index of rice husk ash improved saline soil increased with varying degrees of ash content and curing age.However,when the amount of ash added is higher than 15%,the range of its change becomes significantly weaker,and its compression characteristics become significantly weaker as the amount of ash added and the age of curing increase.As the number of freeze-thaw cycles increases,its mechanical index decreases to varying degrees.On the contrary,its compressibility increases significantly.