Experimental Study On Durability Of Cement Soil In Plateau Lakes Facing Peat Soil

In the plateau lacustrine peat(soil),the soil contains a large amount of humic acid.Humic acids cause corrosion and deterioration of underground structures and structures,leading to the destruction of the original structure and the decrease of strength,which eventually endanger the entire(structure)building life and safety of the study on the plateau lacustrine peat(soil)contained in the soil humic acid substances on the underground structures and components of the corrosive degradation,not only has a strong theoretical value,the actual engineering also has a wide range of guiding significanc e.In this paper,alluvial cohesive soil cement-soil composite is taken as the research object.Through the strength test and humic acid(fulvic acid)corrosion-impregnation test on cement-soil composite,the confining pressure the relationship between strengt h and cement incorporation ratio and age and the interaction mechanism between humic acid(fulvic acid)and alluvial clay soil-cement composite.The main research done the following:(1)The unconfined compressive strength of the alluvial-cohesive clay-soil-soil complex can reach 2 MPa or more;the sensitivity of the strength to the cement-incorporation ratio decreases with the increase of the incorporation ratio,and the cement-soil complex is finally obtained,the empirical formula of the final(90d)intensity was predicted from the previous(7d)intensity.(2)In this paper,the "corrosion softening depth" is used as the index to determine the degree of influence of the fulvic acid solution on the corrosion and degradation of the cement-soil composite sample,and this index can be a good description of the degree of corrosion degradation of the cement-soil composite with the fulvic acid solution;The depth of softness test equipment in the existing test equipment after the comparison,after the study confirmed that t he use of SYD-2801 E penetration tester,and the original equipment for a simple transformation,accuracy:0.01 mm.(3)The fulvic acid solution has a corrosive effect on the erosion and alluvial clay soil-cement complex;the corrosion-softening depth of the cement-soil complex increases with the acidity and the soaking time of the fulvic acid solution,and is increased by acid consumption and corrosion.According to the growth trend of the depth over time,the effect of corrosion degradation can be divided into two phases.The first phase is the rapid corrosion phase and the second phase is the relatively stable corrosion phase.(4)The long-term corrosion immersion test process of cement-soil composites by fulvic acid solution concluded that the empirical formula is e stablished by the law of the change of the corrosion softening depth with the growth of the corrosion immersion time,which can be used in long-term humic acid environments.The cement-soil building structure is predicted by the reduction of structural volum e and bearing capacity caused by the influence of corrosion.For example,the joint prediction formula given in c hapter 5 of this paper can predict the reduction of the vertical compressive bearing capacity of a composite foundation flexible pile caused by the reduction of the cross-sectional area of the composite f oundation affected by corrosion.The reduction of the cross-sectional area of the foundation leads to a joint prediction formula for the reduction of the vertical compressive bearing capacity of a flexible foundation with composite foundations;thus,it can provide some reference for the early prediction of the degradation of underground structures affected by the long-term corrosion of humic acid,in order to ensure the safety of the entire building structure.