| Most of the land after reclamation and tidal flat reclamation is sludge soil.Sludge soil has the characteristics of high water content,low bearing capacity,large deformation under load and long consolidation time.If not treated,it is difficult to be directly applied as the foundation of construction(structure).In order to meet the requirements of large-scale mechanical construction,it is necessary to carry out advanced treatment of shallow foundation soil.The soil solidification method is a simple and efficient treatment method,and the use of industrial waste to prepare a curing agent can not only reduce the cost of the curing agent,but also obtain better curing effect in many occasions,and at the same time alleviate the difficulty of industrial waste disposal,land occupation and secondary pollution.Control sludge soil by industrial waste,which have great economic and environmental benefits.To this end,The following work were carried out in this thesis:(1)The characteristics of various kinds of soil curing agent,the influence of water and organic matter on the solidification of silty soil were analyzed in depth.Considering factors such as curing effect,curing cost,and the difficulty of material acquisition,industrial wastes such as fly ash,phosphogypsum and calcium carbide slag were selected as the components of curing agent.(2)The mixture design experiment was adopted,the dosage of fly ash,phosphogypsum and calcium carbide slag as the influence factors,and the unconfined compressive strength of the solidified soil was tested as the response value.The regression equations of 3 days,7 days,and 28 days were obtained.Through the single factor effect analysis and the analysis of the curing effect at each age,the formula of curing agent ZDJX18 was determined to be fly ash:phosphogypsum:calcium carbide slag=21.6:26.8:51.6.Then the curing mechanism was analyzed with electron microscopy tests.(3)The response surface method of the central composite design was adopted,the water content,organic matter content and curing agent dosage as the influence factors,and the unconfined compressive strength and water stability coefficient of solidified soil at 3,7 and 28 days were tested as the response value.Regression models of unconfined compressive strength and water stability at different ages were obtained.Then the curing effect of sludge soil was studied by anova analysis,single factor analysis and interaction analysis.(4)The cement and lime-fly ash were compared with ZDJX18 to investigate the curing effect and cost price of the three curing agents.The test results showed that ZDJX18 had the best economic applicability. |
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