Mechanical Behavior Of Gravelly Soil And Analysis Initiation Of Debris-flows In Jiangjia Ravine

There are gravelly soil distributed grain diameter widely in Jiangjia Ravine, the mechanical behavior of gravelly soil is important for initiation of debris-flows. This thesis researches on gravelly soil distributed in Jiangjia Ravine, base on information selected, site investigation, a series of experimental study on the gravelly soil used the large scale direct-shear equipment and triaxial test apparatus, analysis the mechanical behavior based on the critical soil mechanics and static-liquefaction theory, compare the mechanical behavior with the phenomenon in initiation of debris-flows. The research work involves several aspects as follows:1. Summarize and discuss three conditions and two factors of occurrence for debris-flows in Jiangjia Ravine, illuminate the circumstance of debris-flows in Jiangjia Ravine, such as geological, climate, geographic and landform characters of circumstance.2. The large scale direct-shear equipment developed by Institute of Rock and Soil Mechanics, CAS, is used to test the direct-shear strength behavior of original samples with different coarse content(>5mm) ,water content and dry density. Found the relationship between direct-shear strength and coarse-content, characteristic index of grain distributed curve, wate-content and dry-density.3. The samples were treated integrative similitude of grain diameter before triaxial test. Based on the result of different density under undrained condition, analysis the character of stress-strain, pore-water pressure and stress path, research the critical-state, strength of steady-state, pore-water coefficient and static liquescence of saturated loose sample, found the differentia of different density under different confining pressure.4. The mechanical behavior of gravelly soil in Jiangjia Ravine and the critical phenomenon in process of debris-flows initiation are analyzed relatively, and analyze the actions in the initiation of debris-flows, in order to explain the mechanism of failure and transformation of debris-flows under different action.