Study On Experimental Transformation Of Landslide Into Debris Flow

Transformation of landslide into debris flow relates to landslide initiation, themotion form and debris flow initiation. It is an advanced and fundamental theoreticalissue in the current debris flow science. The study of the issue not only has great valueof scientific theory but huge applications.Analyze the fundamental theoretical issue base on the information of home andabroad research status. The mechanism and process of transformation of landslide intodebris flow has been studied with the laboratory experiments. Carrying out a systemiclaboratory physical and mechanical properties experiment of soil and conducting modeltest to monitor the variation of soil parameters during this process, we have studied thetransformation of landside into debris flow initiation and process in given rain, theresults obtained are as follows:(1) Based on the literature review of transformation of landslide into debris flow,Analyze the theoretical basis which is Mohr-shear strength theory, penetration theoryand the adsorption, expansion characteristics of clay minerals.(2) Selected soil samples outside, obtained its physical parameters by testingphysical properties of the soil samples in laboratory. Analyzed mineral composition ofthe soil samples by X-ray spectral analysis, the content of quartz was66.7%, the contentof clay mineral was31.2%. Soil structure was known through the particle size analysis.(3) The variation of mechanical parameters of the soil was analyzed throughsensitivity tests. The maximum dry density and optimum moisture content of soil withdifferent soil-rock ratios was obtained by soil compaction test. The soil osmoticcoefficient in different compactedness was tested by penetration test. The changingregularity of shear strength of soil with different moisture content and compactednesswas assayed by the direct shear experiment. These test results provided physicalreference for model experiments.(4) Set up the test parameters and combination of the indoor model test aftersumming up the past research work and analysis of indoor physical mechanics testresults. In this article, the transformation of landslide into debris flow process wasmainly studied, i.e. the landslide failure process. On the loose earth which overlies thebedrock of an angle of30degree, the soil-rock ratio was4:6，the thickness of slope body was60cm, the model experiment of landslide into debris flow was conductedthrough antecedent rainfall of120mm and short diachronic rainfall intensity of16.7mmper10min, which revealed that the mechanism of the transformation through theanalysis of the change of the water content, the pore water pressure and surfaceelevation with rainfall duration.