Study On The Effect Of Seawater Mixing On The Reinforcement Performance Of Saline Soil

Taking the reinforcement of the soft soil foundation of a project in the coastal area of Huanghua Port in Cangzhou as the research background,in the previous experimental research,the cement ground fine slag composite curing agent was used to solve the problem of strengthening the saline soil foundation.At the same time,the existence of seawater was also found in the area Saline soil reinforcement has a certain effect.In order to explore the effect and mechanism of seawater mixing on the strength of saline soil,it is necessary to further study the difference between the tap water mixing and seawater mixing on the strength of saline soil.First,through laboratory experiments,the three main influencing factors of moisture content,type of curing agent and the ratio of cement to ground slag are determined.Secondly,different levels of factors were selected,and the effects of seawater mixing,saline soil content and cement-ground slag ratio on the strength of the reinforced soil were explored through multiple sets of comparative tests.Finally,the experimental method of combining macro and micro was used to test the performance of the reinforced soil:the fracture surface characteristics and SEM micro-morphology of the reinforced soil were observed.Loss on ignition and XRD diffraction patterns were studied and analyzed to explore the effect of different mixing water on the strength of the reinforced soil.The research results show that:1)When the saline soil content is 80%and the ratio of cement to slag is 1:1,the unconfined compressive strength of the seawater mixed reinforced soil is about 42%higher than that of the tap water mixed;and When the ratio of cement to slag is 1:3,the unconfined compressive strength of the reinforced soil mixed with tap water is about 23%higher than the reinforced soil mixed with seawater.2)No matter the seawater mixing or tap water mixing reinforced soil,there is no obvious difference in the composition of the formed solids.The well-formed minerals in the reinforced soil mainly include quartz,calcite and a newly generated zeolite?CaAl₂Si₂O₈·4H₂O?.The feldspar,albite and kaolin in the saline soil participated in the formation of zeolites?CaAl2Si2O8·4H2O?.3)The cementation of hydration products is the main factor affecting the strength of the reinforced soil.The amount of hydration products in the voids of each phase of the solidified soil determines the strength of the reinforced soil.When the amount of hydration products is not much different?about 1%?,the strength of the solidified soil is not determined by the single factor of the amount of hydration products,but by the compactness of the reinforced soil structure and the cementation of the hydration products.Decide.4)In the seawater environment,the hydration reaction of cement proceeds faster,but due to the large amount of free ions such as Cl^-and SO₄^2-in the seawater environment,their reaction with the hydration product Ca?OH?2 makes the reinforced soil alkaline Decline,resulting in insufficient slag excitation.5)The active metal cations in seawater have higher valence and higher concentration than the cations in tap water.Ion exchange can reduce the zeta potential of the soil colloidal particles,which further reduces the thickness of the electric double layer and makes the reinforced soil more crystalline Increased density.This subject explores the effect and mechanism of different mixing water?seawater,tap water?on the strength of reinforced soil,broadens the scope of application of coastal saline soil reinforcement methods,and reduces the construction cost of similar projects.It has a certain guiding role for similar research.