Biological Enzyme Modified Stress Strain Of High Liquid Limit Soil Relationship And Calculation Method Of Roadbed Deformation

With the acceleration of the pace of highway construction in China,the roadbed engineering should have sufficient strength and stability as the main project of the expressway.In recent years,there are different levels of high liquid limit soils in the construction of expressways,and the existence of this bad soil will affect the construction quality of the project.Therefore,the treatment of high liquid limit soil is particularly important,and the high liquid limit soil is modified by physical and chemical methods before use.In this paper,through the combination of laboratory test and theoretical analysis,the stress-strain relationship and the calculation method of subgrade deformation of modified high liquid limit soil of bio-enzyme soil curing agent were studied,and the engineering properties of improved high liquid limit soil were further explored.Based on the Science and Technology Project of Hunan Provincial Communications Department(No:200944)and the Key Discipline Construction Project of Hunan Province(2013ZDXK006),this paper studies the relevant literatures at home and abroad,and takes the high-liquid and high-liquid limit soil as the research object.Experimental research and theoretical analysis.The main research work carried out is as follows.1.Experimental research work(1)Basic physical and mechanical properties of high liquid limit soil:Basic soil tests were carried out to determine the basic physical and mechanical indexes of high liquid limit soil.(2)Triaxial test study of high liquid limit soil:The triaxial test was carried out on different kinds of biological enzyme modified soil by using the consolidated undrained module of the triaxial test system.(3)Isobaric consolidation test of high liquid limit soil:Through a triaxial test system,a series of isobaric consolidation tests were carried out on biologically modified soils with different dosages.2.Theoretical research work(1)Through the analysis of indoor geotechnical test results,the relationship between the boundary water content,the maximum dry density,the optimum water content and the amount of biological enzymes in the improved high liquid limit soil was explored.(2)According to the results of triaxial consolidation undrained test and isostatic consolidation test,the stress-strain relationship and strength variation of different enzyme-modified high liquid limit soils were discussed.(3)A modified Cambridge model of bio-enzyme modified high liquid limit soil was established,and the influence of biological enzyme content on the parameters related to the modified Cambridge model was determined.The functional relationship between the amount of biological enzyme and the relevant parameters of the model was obtained.formula.(4)Based on the modified Cambridge model theory,the calculation method of subgrade settlement is proposed and compared with the stratified summation method.3.Through the above analysis and summary,you can get:(1)With the increase of the amount of biological enzymes,the liquid limit is decreasing,and the plastic limit is increased.The biological enzymes with different dosages have little effect on the optimum water content,and the optimum water content is about 25%;Both the force and the internal friction angle show a relationship of increasing first and then decreasing.When the amount of biological enzyme reaches 6%,the change is most obvious.The shear strength of the modified high liquid limit soil increases and then decreases with the increase of biological enzyme.The change of compression characteristics is firstly decreased and then increased,and when the amount of biological enzyme is 6%,the compression effect is obvious.(2)The results of triaxial consolidation undrained test and isostatic consolidation test show that the stress-strain relationship is strain-hardening,and the biological enzyme can effectively improve the shear resistance and compression resistance of the soil,and in the biological enzyme.When the dosage is 6%,the compression performance is obvious.(3)By correcting the Cambridge model,using the Cambridge model method to calculate the settlement of the subgrade,compared with the settlement of the subgrade calculated by the stratified sum method,as the amount of bio-enzyme incorporation increases,the sedimentation decreases with the increase of the depth.Moreover,the deviation between the results calculated by the Cambridge model method and the stratified sum method is not more than 3%,and the sedimentation amount is minimized when the biological enzyme content is 6%.In summary,this paper studies the stress-strain relationship of modified high liquid limit soil and the calculation method of subgrade deformation by carrying out relevant experimental and theoretical research on improving high liquid limit soil,revealing the stress of improved high liquid limit soil sample.The strain relationship and the deformation law of the roadbed have laid a theoretical foundation for the study of the deformation of high liquid limit soil,and they have important guiding significance for the quality of the high liquid limit soil.