Temperature Effect On Dynamic Characteristics Of Saline Soil Under Bidirectional Cyclic Loading

Bayannur is an important transportation hub in the northwest region of China.Its strategic position in the development of the western region is extremely important.There will be dense railway lines in the near future.According to the distribution of sulphate soil in China,the area belongs to arid and semi-saline saline soil areas in the upper and middle reaches of the Yellow River.This paper aims at this special soil quality and studies the dynamic characteristics of the sulfated soil foundation under the bidirectional excitation load generated by high-speed train operation.Based on the engineering background of a high-speed rail line being built in the area,the article first investigated the basic physical and mechanical properties of geological soil in Bayan Nur area.Secondly,the effects of temperature,salinity and radial load on the strain of sulfated soil under biaxial excitation were studied.Finally,the effect of salinity and radial load at room temperature on the hysteretic curve,dynamic shear modulus and damping ratio of sulfated soil samples under biaxial excitation are studied.The study found:(1)There is a poor grading of silt over large areas in BayanNur area which is classified as a strong sulphate soil according to its salinity grade.The salt swelling and subsidence characteristics of foundation soil will have a great impact on local buildings and roads.(2)Saline soil samples produce greater deformation when the temperature is higher,Under bidirectional excitation load.When the salt content of the sample is 0-6%,the higher the salt content,the greater the axial deformation of the sample.The radial load has an inhibitory effect on the axial compression of the specimen.The larger the magnitude of the radial cyclic load is,the more obvious the inhibition is.(3)The sample hysteresis curve is fuller the dynamic shear modulus and damping ratio are smaller When the sample salt content is larger at room temperature.(4)are smaller When the sample the amplitude of radial cyclic load is smaller at Room temperature.