Abstract:To analyze the mechanical properties of remodeled Pisha-sandstone in southern Ordos city of Inner Mongolia Jungar Banner, the effect of freeze-thaw on mechanical properties of the remodeled Pisha-sandstone soil was studied by using the TSZ-6A full-automatic static triaxial apparatus, at room temperature for different freeze-thaw cycles of triaxial compression test. Under the condition of different freezing and thawing cycles(0-7 times)and different confining pressure(50-300 kPa), the changing laws of Pisha-sandstone shear strength, angle of internal friction and cohesion, and the modulus of elasticity were obtained. The results indicate that in the same freeze-thaw cycle index, with the increase of confining pressure, the peak of shear strength shows linear growth. In the same freeze-thaw cycle index, the effect of freezing and thawing cycle on the shear strength is mainly manifested in the cohesion of influence, for which the cohesion of Pisha-sandstone decreases with the increasing moisture content, and internal friction angle fluctuates with the increasing of moisture content. Before the saturated moisture content, the elastic modulus basically remains the same, so the moisture content and freeze-thaw on its plasticity need not be considered. After the saturated moisture content, the linear segment of partial stress-strain curve no longer exists, and Pisha-sandstone elasticity disappears, and fully enters the plastic stage. This study provides a basis for Ordos Pisha-sandstone damage mechanism and control of freeze-thaw erosion.
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