Study On High-strength Steel Fiber Reinforced Concrete With Inner Steel Plate In Frozen Shaft

With the depletion of shallow coal resources,in order to ensure the sustainable development of the national economy,we must develop alluvial deep coal resources and build wellbore.When the freezing method is used,the wellbore support becomes a major technical problem.At the same time,when the Freezing method is used to repair the wellbore in the alluvium,the thickness of the casing wall should be as thin as possible,also need to use high-strength wall structure.Based on this,in order to solve the problem of support and repair of frozen shaft,the paper puts forward the structure of the concrete wall of the high-strength steel fiber reinforced concrete with inner steel plate.The deformation,stress and strength characteristics of the new wellbore structure are studied by theoretical analysis,model experiment and numerical calculation.Firstly,according to the elastic-plastic mechanics,the stress and deformation of the shaft section are analyzed theoretically,and the calculation formula of the ultimate bearing capacity of the borehole wall is deduced.Then,in the experiment of model,the material and mixing ratio of CF80 and CF90 were obtained by the experiment of high strength steel fiber concrete.According to the similarity theory,the similarity criterion of the borehole wall model test is deduced,and the model parameters are determined.Through the model experiment of this wall structure,the stress and ultimate bearing capacity are obtained.The experimental results show that the inner steel plate and the steel fiber have the effect of restraint and toughening respectively,and the brittleness of the new type of borehole wall structure is lower than that of the ordinary high-strength concrete wall structure,which shows more excellent toughness,more safe and reliable in conclusion.In the numerical calculation,ANSYS software was used to simulate the ultimate bearing capacity of the steel fiber reinforced concrete core wall of the inner steel plate,and the stress and ultimate bearing capacity are obtained.Compared with the experimental results,the two are close.