Experimental Study On Dynamic Constitutive Model Of Bio-enzyme Treated Silt

The dynamic stress-strain relationship of bio-enzyme treated silt have been analyzed.The effects of enzyme content,confining pressure and vibration frequency on the parameters of Hardin-Drnevich dynamic constitutive model and Martin-Darvidenkov dynamic constitutive model are studied,and the modified dynamic constitutive model of bio-enzyme treated silt is established.Firstly,through the basic physical and mechanical properties test of bio-enzyme treated silt,the effect of bio-enzyme content on the basic physical and mechanical indexes of silt is studied,and the best amount of biological enzyme is obtained.Then through a series of dynamic triaxial tests with different amount of biological enzyme,different confining pressure and different frequency,the influence of different factors on the dynamic backbone curves of bio-enzyme treated silt is studied.Based on the Hardin-Drnevich model and Martin-Darvidenkov model,the relationship between enzyme dosage and model parameters is established,and the modified Hardin-Drnevich model and modified Martin-Darvidenkov model based on enzyme dosage are obtained.Finally,the two dynamic constitutive models are verified and the applicability is compared.The main contents are as follows.(1)The basic physical and mechanical indexes of silt samples are obtained by soil particle screening test,liquid plastic limit test,standard compaction test and direct shear test.The standard compaction test and direct shear test are carried out for the improved silt with different amount of biological enzyme,and the effect of enzyme content on the basic physical and mechanical indexes is explored,and the optimal amount of biological enzyme is obtained.(2)The dynamic skeleton curves of silt under different enzyme content,confining pressure and frequency are obtained by triaxial test.It is found that it is strain hardening type.The effects of enzyme content,confining pressure and frequency on the dynamic skeleton curve are analyzed.(3)Based on Hardin drnevich dynamic constitutive model,the dynamic stress-strain relationship curve of the modified silt by biological enzyme is fitted.The relevant fitting parameters of the dynamic constitutive model are calculated,the influence rules of different factors on the model parameters are studied,the correlation between the amount of biological enzyme and the model parameters is explored,and the modified Hardin-Drnevich dynamic constitutive model based on the biological enzyme content is proposed.(4)The dynamic stress-strain relationship curve of bio-enzyme treated silt is fitted by Martin-Darvidenkov dynamic constitutive model.The parameters of the model are calculated,the influence of different factors on the three parameters is analyzed,the correlation between the amount of biological enzyme and the model parameters is explored,and the modified Martin-Darvidenkov dynamic constitutive model based on the biological enzyme content is proposed.(5)The fitting effect of the two dynamic constitutive models on the dynamic stress-strain curves of silt is compared and analyzed.Through the comparison between the test results and the fitting results,it is found that the fitting effect of Martin-Davidenkov dynamic constitutive model is better than Hardin-Drnevich dynamic constitutive model.To sum up,through the experimental research on the basic physical and mechanical properties of bio-enzyme terateded silt and some results obtained from the dynamic triaxial test research,it provides a reliable experimental basis and a new idea for the further study on the dynamic constitutive model of bio-enzyme terateded silt,and provides a certain reference for the practical application of silt improved by biological enzyme in the future.