Research On Deformation Characteristics And Crack Propagation Law Of Phosphogypsum Stabilized Soil

Aiming at the problems of large amount of industrial waste phosphogypsum piled up in the open air and poor engineering properties of red clay,this paper proposes to use cement and phosphogypsum to improve red clay.Taking phosphogypsum stabilized soil(phosphogypsum+cement+red clay)as the research object,the physical and mechanical properties,water stability,water stability and stability of phosphogypsum stabilized soil are systematically studied by using indoor test analysis method and fracture image recognition analysis technology(PCAS),The main research results are as follows:(1)The addition of cement phosphogypsum can significantly improve the 7d unconfined compressive strength and CBR value of red clay.The results show that the ratio of phosphogypsum to red clay is 1?1,and the CBR value is the highest;CBR value increases with the increase of cement content and compactness.(2)The water stability coefficient first increases and then decreases with the increase of water glass content,and decreases with the increase of water glass ratio.When the dosage of sodium silicate is 2%,the ratio of phosphogypsum to red clay is1?1,and the water stability coefficient is the highest.(3)The liquid plastic limit and plasticity index of phosphogypsum stabilized soil gradually decrease with the increase of phosphogypsum content.When the phosphogypsum content exceeds 10%,it can be directly used as embankment filling.(4)The absolute expansion rate of phosphogypsum stabilized soil decreases with the decrease of ratio,the linear shrinkage rate and horizontal shrinkage rate first increase and then decrease with the decrease of ratio,and the compression coefficient a_v1-2first decreases and then increases with the decrease of ratio.(5)After five cycles of drying and wetting,no cracks were found on the surface of phosphogypsum stabilized soil;The fracture ratio is smaller than that of plain red clay,which increases with the increase of temperature and decreases with the decrease of mixture ratio,The ratio of phosphogypsum to red clay is 1?1,and the fracture rate is the lowest.Considering the road performance of phosphogypsum stabilized soil and the content of cement phosphogypsum,it is suggested that 5%cement and phosphogypsum?red clay=1?1,the road performance and economy of the mixture is the best.The research results can provide scientific basis for the utilization of phosphogypsum and the improvement of red clay,and have important academic significance and engineering application value.