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Understanding the spatial heterogeneity of debris-flow-prone areas holds significant implications for regional risk management, particularly in seismically active regions with geological faults. Despite the significance of this knowledge, a comprehensive quantification of the influence of regional topographical and geological factors on the spatial heterogeneity of debris-flow-prone areas has been lacking. This study selected the Hengduan Mountains, an earthquake-prone region characterized by diverse surface conditions and complex landforms, as a representative study area. An improved units zoning and objective factors identification methodology was employed in earthquake and fault analysis to assess the impact of seismic activity and geological factors on spatial heterogeneity of debris-flow prone areas. Results showed that the application of GIS technology with hydrodynamic intensity and geographical units analysis can effectively analyze debris-flow prone areas. Meanwhile, earthquake and fault zones obviously increase the density of debris-flow prone catchments and make them unevenly distributed. The number of debris-flow prone areas shows a nonlinear variation with the gradual increase of geomorphic factor value. Specifically, the area with 1000 m–2500 m elevation difference, 25°–30° average slope, and 0.13–0.15 land use index is the most favorable conditions for debris-flow occurrence; The average annual rainfall from 600 to 1150 mm and landslides gradient from 16° to 35° are the main causal factors to trigger debris flow. Our study sheds light on the quantification of spatial heterogeneity in debris flow-prone areas in earthquake-prone regions, which can offer crucial support for post-debris flow risk management strategies. [ABSTRACT FROM AUTHOR]

Basalt fiber (BF) reinforced vegetation concrete (VC) technique has attracted the attention of researchers. In order to investigate the reinforcement properties of BF reinforced VC, the optimal BF length and content. Through the single BF pullout test and direct shear test, the properties of interfacial strength between BF/VC and the reliability of the formula for calculating the optimal BF reinforcement length are studied. It has been found that the designed equipment is an efficient method to obtain the interfacial peak shear strength and residual shear strength of BF/VC. Moreover, the direct shear test proves the feasibility of the formula, which is used as a basis for mixing BF length in engineering. The anchoring effect between the cement hydration product and the fiber in the VC changes the mechanical action between BF/VC and significantly improves the shear strength of the interface. Higher dry density effectively enhanced the peak tension of a single BF by 149.23%. The optimal BF length and content make the softening degree of vegetation concrete not evident, which improves the durability of VC engineering. The formula of optimum fiber reinforced length and empirical formula can be used as reference for mixing basalt fiber in practical engineering. [ABSTRACT FROM AUTHOR]

In view of the problem whereby the rock masses in water-level fluctuation zones of reservoir banks are susceptible to deterioration due to soaking-drying cycles, the sandstone of a typical landslide in the Three Gorges Reservoir area is selected as the test object to determine the ion concentration of an immersion solution and rock sample via periodic water-rock microscopic images, quantitative back analysis of the porosity changes caused by the dissolution of rock minerals under soaking-drying cycles, and evaluation of the sandstone porosity evolution. The results show that, 1) in the first two soaking-drying cycles, the generation rate of each ion is relatively high, and after 6 soaking-drying cycles, the ion generation rate tends to remain stable. 2) The volume reduction in calcite is the largest, followed by that in albite and potash feldspar. 3) Small porosity changes result in a considerable decrease in the compressive strength. 4) Sandstone porosity increase leads to an increase in rock pores, which is manifested as a deterioration of the macroscopic rock mechanical properties. Relevant research results could provide a reliable data basis for the study of large-scale reservoir bank slope protection and geological disaster evaluation and prediction. [ABSTRACT FROM AUTHOR]

Vegetation concrete is one of the most widely used substrates for slope ecological protection in China. However, there are still some imperfections that are disadvantageous for plant growth, such as high density, low porosity, insufficient nutrient retention ability and so on. In this paper, the effect of wood activated carbon and mineral activated carbon on the physicochemical properties of vegetation concrete is studied. The experimental results show that the activated carbon proportion in vegetation concrete is positively related to the porosity, permeability coefficient, water holding capacity, and nutrient content and retention ability, while it is negatively related to the dry density, water retention ability, cohesive force and internal friction angle. However, it should be noticed that when the proportion exceeds 2%, the average height, aboveground biomass and underground biomass of Cynodon dactylon decrease with increasing proportion of activated carbon. The effect of wood activated carbon is generally more remarkable than that of mineral activated carbon. In addition, according to the research results, the effect of activated carbon on vegetation concrete can last for at least half a year, although it does slowly deteriorate with increasing time. By comprehensive consideration of the current industry standard, previous research results and economical reasoning, the recommended type of activated carbon is wood, with a corresponding suitable proportion ranging between 1 and 2%. [ABSTRACT FROM AUTHOR]

TiO2/CeO2 composite catalysts were successfully prepared with hydrothermal and deposition-precipitation method. Acquired samples were characterized with diversiform analytical techniques and spectroscopy to ensure their structure, morphology, and light absorption properties. The results manifest that all the samples contain highly crystalline anatase phase. X-ray diffraction (XRD) and scanning electron microscope (SEM) show that the addition of CeO2 inhibited the grain growth without destroying the original appearance, and the inhibition effect of hydrothermal method is more obvious. Structure of the hole was explained combined with the mechanism of reaction. Experimental consequences such as Raman and photoluminescence (PL) spectrum peaks broadening and movement further indicate that CeO2 have been composite with the TiO2 and caused size effect. Compared to the pure TiO2, we can see from the UV-Vis spectrum that the band gap of TiO2/CeO2 is narrower, and the light absorption range is slightly expanded to visible light, which will be hopeful to enhance the photoconversion efficiency. [ABSTRACT FROM AUTHOR]