Experimental Research on Shear Strength of Remolded Debris Flow Structures

Abstract To investigate the strength characteristics of remolded debris flow structures and influencing factors, Jiangjia Gully debris flow deposits in the Yunnan province were chosen as the research object. Considering influencing factors such as gradation types, water contents, and vertical pressures, four gradation types were reconstituted and shear strength tests were carried out on the remolded samples. Based on the interaction between these factors, the influence mechanism of each factor on the strength of the remolded structure was explored, and the strength development mechanism of the remolded structure was analyzed on this basis. The results show that the shear strength of the remolded structure is mainly provided by fine particles and that the effect of water content on the remolded structure is not merely a single feedback mechanism but works together with the external load and inhibits the strength development of the structure in some cases; the degree of influence of each factor on the shear strength of the remolded structure is ranked as follows: vertical load > gradation type > water content > water content * gradation type > gradation type * vertical load > water content * vertical load. At the same water content and gradation, external vertical load has a positive effect on the enhancement of the shear strength of the remolded structure, but at the same vertical load, gradation and water content show an inhibitive effect; the content of fine particles in different gradation structures determines the structural type of the remolded structure, but the water content and vertical load, as external factors, exert a positive impact on the shear strength of the remolded structure via the rearrangement of particles in the structure and the regulation of pore water pressure, which in turn affects the shear strength of the remolded structure.