Improvement Properties Of Fluid Solidified Soil And Its Engineering Application

Fluid solidified soil as a new type of building material,is a mixture with a certain overall strength by adding cementitious material to the loose soil,at the same time by controlling its fluidity by controlling the moisture content and other admixtures.This technology is widely used in road engineering,foundation engineering,municipal pipe gallery and other projects.For fluid solidified soil,the soil properties of different regions are quite different,so the selection of soil curing agent and water content must be based on local conditions,can not be generalized.In this thesis,two materials,cement and lime,were used as the main curing agent,and fly ash and polyvinyl alcohol were used as the auxiliary materials for the excavation of foundation soil in an ecological restoration project in a city.A comprehensive study was conducted on the strength characteristics,compression characteristics and fluidity of the fluid solidified soil with different proportions of curing agent,different total dosage of curing agent and different curing ages.The comparison between convective solidified soil construction method and traditional rammed solidified soil construction method provides theoretical and design basis for the selection of material ratio and construction technology in the project and field experiment.The research results of this thesis are of great significance to further study the theory of flow solidified soil.The main research contents are as follows:（1）Through orthogonal test,the effects of cement,fly ash and polyvinyl alcohol（quicklime,fly ash,polyvinyl alcohol）on the overall curing effect were analyzed.Through the orthogonal tables of L₉（3⁴）and SPSS software were used for range analysis and variance analysis to obtain the optimal ratio of each material in the two curing agents.（2）Through the flow test,the influence of different water content on soil flow under different pouring time is compared,and the time limit of pumping construction under different water content is analyzed.（3）Through the strength test,the strength growth law of cement flow solidified soil and quicklime flow solidified soil at different ages was compared,and the influence of cement group curing agent and lime group curing agent on the curing strength of soil was analyzed.The strength growth law of the soil reinforced by the fluid solidified soil construction method and the conventional compaction solidified soil construction method at different ages is compared,and the influence of two different construction methods on the solidified strength of the soil is analyzed.The empirical formula of the strength of the fluid solidified soil with the amount of curing agent and the curing age is proposed.（4）Through the consolidation compression test,the difference of compression characteristics between cement fluid solidified soil and lime fluid solidified soil is compared.The effects of different curing agent contents and different curing ages on the void ratio,compression coefficient and compression modulus of fluid solidified soil were investigated.（5）Combined with specific engineering cases,the advantages and disadvantages of the flow solidified soil construction method and the conventional compacted soil construction method are compared,and the flow solidified soil construction scheme suitable for most filling projects is proposed.