| The weathered red sandstone soil is characterized by water disintegration,strength weakening and gradation change.Under the double action of rainfall and evaporation,the weathered red sandstone soil in nature is often in the state of alternating between wet and dry,which easily leads to the decrease of soil strength and the increase of deformation,thus posing a threat to the long-term stability and security of natural slope and soil structure.Therefore,it is of great significance and engineering application value to carry out research in this field.Based on the weathered red sandstone soil in southern jiangxi province,the strength and consolidation deformation characteristics under the action of dry and wet cycling were experimentally studied.The main research contents and results are as follows:(1)Through laboratory tests,the natural moisture content,natural density,liquid plastic limit,maximum dry density,specific gravity and other basic physical indexes of the red sandstone weathered soil were obtained,which provided a basis for the design,preparation,analysis and calculation of the test soil samples.(2)The shear test of red sandstone weathered soil under dry and wet cycle conditions was carried out,and the shear strength under different initial moisture content,dry and wet cycle amplitude and vertical stress after 7 dry and wet cycles were obtained.The internal friction Angle and cohesion were obtained by fitting the morecoulomb formula.(3)Based on the results of the shear test,the influences of the number of dry and wet cycles and the amplitude of dry and wet cycles on the shear strength,cohesion and internal friction Angle of the weathered red sandstone soil were analyzed,and the reasons were obtained.The attenuation law of shear strength and the variation law of internal friction Angle and cohesion were obtained.(4)Be carried out by dry-wet cycle under the condition of red sandstone weathering soil consolidation compression test,the vertical stress,initial moisture content and different soil samples under the action of compress dry-wet cycle amplitude,through the compression quantity calculated after each cycle,cycle amplitude soils of different initial moisture content,void ratio,calculated the compression coefficient and compression index,compression modulus and deformation modulus of deformation characteristics of indicators,and the indicators are obtained along with the change rule of cycling times.(5)This paper analyzes the relationship between the compression amount generated by different vertical stresses,the compression amount when the compression deformation reaches stability and the number of cycles,probes into the reasons for the increase of the compression amount of soil samples caused by the dry and wet cycling,and obtains the rules of the compression amount and the number of cycles when the compression deformation of test soil samples reaches stability and the functional relations. |
