Research On The Strength Characteristics Of Expansive Soil Freeze-thaw Cycles In Daqing Area, Heilongjiang Province

The expansive soil in the northern tendering project of Daqing area in Heilongjiang Province is a special soil in the seasonal frozen soil area.The high hydrophilicity of this type of expansive soil is extremely destructive in the freeze-thaw cycle of the frozen soil area in the northeast.The frost heaving caused by the seasonal changes in the year will have various destructive effects on public transportation facilities and buildings such as highway tumbling and bridge culvert corrosion.The seasonal temperature of seasonal frozen soil area changes periodically.The surface of the cold area can reach more than 100 times within one year.The internal mechanism affecting the expansion and contraction of expansive soil is mineral composition and microstructure.It is the effect of water on expansive soil.Therefore,when studying the mechanism of freeze-thaw cycles,the shear strength parameters of expansive soils are the basis for the study of expansive soils.In this paper,the expansive soil of the Tengnan project was taken as the research object.Through a series of laboratory tests,the experimental study on the response characteristics of soil under different freezing and thawing temperatures,freeze-thaw cycles and water content in remolded soil was carried out.The specific effects of various factors in the cyclical action on the strength characteristics of expansive soils in this area,the corresponding problems of the fitting function analysis of multiple linear regression analysis models were established,and the strength characteristics of the expansive soils in the region under the influence factors of freeze-thaw cycles were obtained.The regular conclusions provide guidance for the subsequent engineering design and construction of expansive soils in the area to improve people's awareness of the strength characteristics of expansive soils in the area and reduce safety hazards.The main research contents include:(1)Through on-site sampling,the main physical and chemical properties of soil samples were examined,and the research results of previous scholars were consulted to understand the distribution law,distribution characteristics and major engineering hazards of expansive soils.(2)Through the basic physical and chemical properties test,the basic soil indexes such as the particle size composition,water content,density,bulk density,gravity and liquid-plastic limit water content of the sampling point soil are obtained.(3)Through the single factor freeze-thaw test,the frost heave property of soil under different influencing factors was analyzed,and the changes of shear strength parameters of soil under the influence of freezing and thawing temperature range,number of freeze-thaw cycles and water content were obtained.law.(4)Comprehensive experimental data,based on SPSS software and MLP multilayer perceptron(neural network),establish multiple linear regression equations and analyze,establish the shear strength parameter index under different temperature,freeze-thaw cycles and water content The shear strength prediction model analyzes the importance of each influencing factor and tests the degree to which the model fits the actual situation.