Study On Mechanical Properties Of Red Beds Soft Rock Filling Material And Long-term Characteristics Of Embankment Under Dry And Wet Cycle

The red beds is widely distributed in China,the red beds soft rock filling material are mostly used as embankment filling material in red beds area.The characteristic that the red beds filling material disintegrating easily can cause many road damages,so special means of disposal are needed.At present,the measures adopted in the construction project have achieved certain results,but the reasons for the deformation and damage of the red beds embankment under the long-term dry-wet cycle have not been ascertained,and there is a lack of treating measures.In this paper,the triaxial test of dry-wet cycle is carried out to study the evolution of mechanical properties of red beds soft rock filling material under dry-wet cycle.Then,based on the experimental results,the long-term deformation and stability characteristics of red beds embankment are analyzed,and the following work is completed:Firstly,the CD triaxial test of the scaled compacted red beds soft rock filling material after 0⁸ time of dry and wet cycles was designed and completed,and the stress-strain relationship curve and Mohr-Coulomb strength index of 0⁸ time of dry and wet cycle samples were obtained.In the analysis of the evolution of peak strength,it is found that the peak strength of the red beds soft rock filling material decreases first and then increases with the increase of the number of dry and wet cycles,which is different from the general geotechnical materials.Then the mechanism of the evolution in strength of the red beds soft rock filling material under the dry-wet cycle is studied in depth.Based on the analysis of the relationship between the change of the solid volume and the evolution in strength under different dry-wet cycles,the mechanism of strength evolution is surmised,then the rock block lateral disintegration test is designed to verify the conjecture.It is founded that the strength of the rock block in the red beds soft rock filling material under the dry and wet cycle does not disintegrate which is the reason for the characteristics of special strength evolution.Finally,based on the experimental data,the Modified Cambridge model was used to calculate the parameters of he red beds soft rock filling material with different dry and wet cycles.The variation of the material parameters of the he red beds soft rock filling material was analyzed.On this basis,Flac^2d was used to calculate the deformation and safety factor of the red beds embankment under different wet and dry cycles,and the deformation and stability characteristics of the red beds embankment under long-term conditions were ascertained.