Study on Damage Properties and Constitutive Model of Phosphogypsum Cementation Body with Different Fiber Content
In order to improve the strength and toughness of phosphogypsum cementation body,the experiment of adding fiber to improve the mechanical strength characteristics of phosphogypsum cementation body was carried out.The damage law of phosphogypsum-based composite cement with polypropylene fiber content of 0,0.5％,0.75％,1％and 1.25％was studied.The results are as follows.Frstly,with the increase of polypropylene fiber content,the peak strain and compressive strength of phosphogypsum cementation body increase to a certain extent,and the compressive strength and elastic modulus increase first and then decrease.The optimal fiber incorporation amount is 0.75％.Secondly,the stress-strain curves of cement specimens with different fiber contents have similar shapes,and the differences between the stress-strain curves of fiber-doped cements and ordinary phosphogypsum cements show that the incorporation of fibers can improve the post-peak residual strength and toughness of the cements,and obviously improve the compressive strength of the phosphogypsum cements.Thirdly,based on the strain equivalence theory and statistical damage theory,five kinds of damage correction coefficients were introduced,and the uniaxial compression damage constitutive model of fiber-doped phosphogypsum cementation body was derived.The uniaxial compression damage constitutive equation and damage evolution equation of phosphogypsum cementation body with different fiber content were established.Finally,comparing the theoretical curve with the experimental curve,it is found that each curve has a similar shape and the two are in good agreement at the peak,indicating that the established theoretical constitutive model has certain reference value for the analysis and research of phosphogypsum cementation body with different fiber contents.The research results can provide some theoretical support for the application of phosphogypsum-based composite materials in the field of solid waste cemented filling.
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维普
