| Slope collapse erosion is a special kind of erosion. Understanding the sedimentformation process of slope collapse erosion is the key to the research on themechanism of slope collapse erosion.In this thesis,three typical eroded slopes werechosen in Anxi county in Fujian province and the soil samples were collected fromeach of the three slopes from the bottom up.Various element contents of the soilsamples of different grain sizes were analyzed and the element contents which wereobviously different from each other were selected as the best fingerprintfactors;Meanwhile, the concentrations of various fingerprint factors in the sedimentforming after the rainfall erosion were analyzed as well and the contribution rates ofvarious soil layers to sediment were determined through the mltivariate discriminantmethod and the principal component analysis. Besides,the composite fingerprintidentification method which was suitable for the analysis on the sediment source ofthe slope collape erosion in the granite area in the south was determined; Thesediment source of every parts of the slope collape system was analyzed through thismethod and the results were as follows:1.Through analysis on the69kinds of the determined indices of the soil samplesof different grain diameters in the granite area in the south,it was showed that throughKruskal-Wallis H-test,the eroded slope A had36fingerprint factors under differentgrain sizes while the eroded slope B and C had22factors and31factors respectively.2.Through the stepwise discriminant analysis method,the fingerprint factorswhich were selected by Kruskal-Wallis H-test and different from each other arecombined to gain the best composite factors.The number of the best compositefingerprint factors of slope A,slope B and slope C was6,5and5respectively.3.Through monitoring and sampling toward the slope collapse in the researcharea and according to the multiplex mixed model,the contribution rate of the threesource regions to the sediment was obtained.As for slope collapse A,the relativecontribution rates of the red soil layer,the sandy soil layer and the fragment layer tothe sediment of the collapse heap were66.24%,16.06%and17.7%respectively and the relative average error was2.70%;the relative contribution rates of the red soillayer,the sandy soil layer and the fragment layer to the sediment of the alluvial fanwere10.25%,38.99%and50.76%respectively and the relative average error was3.29%.As for slope collapse B,the relative contribution rates of the red soil layer,thesandy soil layer and the fragment layer to the sediment of the collapse heap were25%,42.08%and32.92%respectively and the relative average error was5.32%;therelative contribution rates of the red soil layer,the sandy soil layer and the fragmentlayer to the sediment of the alluvial fan were30.08%,42.31%and27.67%respectively and the relative average error was6.37%.As for slope collapse C,therelative contribution rates of the red soil layer,the sandy soil layer and the fragmentlayer to the sediment of the collapse heap were31.38%,50.31%and18.32%respectively and the relative average error was7.64%;the relative contribution rates ofthe red soil layer,the sandy soil layer and the fragment layer to the sediment of thealluvial fan were29.13%,40.54%and30.33%respectively and the relative averageerror was9.82%.4.According to the computing result,the GOF values of the collapse heap and thealluvial fan of the slope collapse A obtained by this experiment were0.86and0.90;theGOF values of the collapse heap and the alluvial fan of the slope collapse B were0.82and0.91;the GOF values of the collapse heap and the alluvial fan of the slope collapseC were0.92and0.88;it was showed that all the GOF values were more than0.8,which again proved that the result obtained by this mixed model was acceptable. |
