Influence of reservoir water level variation on slope in lab. flume test

The Tenth International Symposium on Mitigation of Geo-disasters in Asia. Kyoto Symposium. Place: Uji Campus, Kyoto University. Date: 7 October 201

Experimental study to identify premonitory factors of landslide dam failures

Identifying premonitory factors before final failure for long-existing landslide dams is of high importance in disaster prevention and risk reduction. In this study, a series of large-scale (outdoor) experiments were designed and conducted to identify premonitory factors that may be used in failure prediction for actual landslide dams. Surface deformation, especially dam-crest settlement, dam seepage-water turbidity and self-potential across the dam crest were selected as the target parameters. Changes in these parameters showed apparent correlations between each other. Based on the monitoring data obtained and the observation performed during the tests, the deformation and failure sequence of the dam model can be separated into four time-sequential periods: 1) Emergence of seepage water and front wetting. In this period, the monitoring parameters did not show any obvious changes. However, wetting was observed in the downstream face. 2) Hyperconcentrated flow discharge. In this period, water flowed out of the drainage channel, and the vertical deformation of the dam body became obvious, while the turbidity of the seepage water increased. 3) Emergence and development of cracks on the dam crest. In this period, the dam-crest settlement also increased. 4) Sudden collapse and final failure. In this period, self-potential across the dam crest decreased rapidly, and the dam-crest settlement reached a peak value. Therefore, dam-crest settlement, seepage-water turbidity and self-potential changes can be regarded as premonitory factors of landslide dam failur

Investigation of shallow landslides triggered by heavy rainfall during typhoon Wipha (2013), Izu Oshima Island, Japan

金沢大学理工研究域地球社会基盤学系BackgroundTyphoon Wipha struck Izu Oshima Island on 16 October 2013, bringing heavy rainfall. It triggered widespread landslides on the western slopes of Izu Oshima Island, and caused significant loss of life and serious property damage. Authors have conducted both field investigations and laboratory experiments in an effort to understand the initiation mechanism of the shallow landslides triggered by heavy rainfall.ResultsPyroclastic-fall deposits on the slopes are well-graded fine sand with silt, and with high specific gravity and void ratio. These soil properties will affect the mechanical and hydraulic characteristics of soil. The results of consolidated-undrained triaxial tests show that the effective internal friction angle of soil is 38.7 degrees. The results of triaxial tests using pore-water pressure control show that static liquefaction can occur in porous pyroclastic-fall deposit layers due to rainfall infiltration.ConclusionsThe effective strength of pyroclastic-fall deposits on the upper slope is quite high. Even though the slope is very steep (over 30 degrees), it can remain stable while in an unsaturated condition. Due to heavy rainfall and the porosity of the pyroclastic-fall deposits, rainfall can quickly infiltrate into soil layer. Moreover, the interface above the underlying basalt will stop groundwater infiltration, acting as an impervious boundary. With increase of groundwater level, the effective strength of the porous soil will decrease. Finally, static liquefaction can be triggered, leading to the generation of shallow landslides on the upper slopes

Dynamic response charactertstics of long petroleum pipelines extending along mountain ridge under strong earthquake

There are many long petroleum pipelines extending along mountain ridges in the mountainous areas of western China.Dynamic responses of the pipelines under strong earthquake have significant effect on their safe service ability.It is necessary for the related investigations to provide guidance for practical construction of the pipeline projects.In terms of a typical section of this kind of oil pipelines at Longmacao village, Yusi, Yunnan, a pipeline-slope 3D numerical simulation model is established considering engineering geology conditions of the slope.Further, dynamic responses of the pipeline including its displacement, axial force, shear force and bending moment as well as overall stability of the pipeline-slope system are computed using FLAC3D program with inputting Wenchuan seismic wave, and the seismic responses at some typical moments such as the moment at peak value of the horizontal acceleration and after the earthquake are specifically obtained.The results show that internal forces of the pipeline reach their maximum values after the earthquake, and the axial force gets high level under strong earthquake but the shear force and bending moment are in small level with about 1% magnitude of the former.Besides, vertical seismic wave has little effect on internal forces of the pipeline, and the position of the maximum internal forces is near the intersection of the pipeline and fault.During strong earthquake, the pipelines appear mainly elastic and plastic deformation in the horizontal and vertical direction, respectively.The accumulated deformation is the major factor to influence internal forces of the pipelines, whose maximum occurs at the moment after the earthquake

City Green Economy Evaluation: Empirical Evidence from 15 Sub-Provincial Cities in China

City green economy plays an important role in the development of low-carbon economy and the achievement of sustainable development of economy, society and ecological environment. From the perspective of economy, society, environment and resources, the evaluation of the green economy in urban areas tends to offer us a new insight into the green economy of cities. This paper is about the creation of a novel urban green economy evaluation model and its application. First of all, we established a city green economy evaluation index system based on R cluster analysis and coefficient of variation. Secondly, based on the nonlinear weighted utilizing entropy weight method, a city green economy evaluation model is established based on inferior constraints. Thirdly, by comparing the differences between evaluation rankings under inferior constraints and non-inferior constraints, the advantageous factors and the disadvantageous ones in urban green economy development are obtained. The proposed model has been verified with the data on 15 sub-provincial cities in China. Empirical analysis results show that: (1) The proposed approach can accurately find out the advantageous and disadvantageous factors for each sub-provincial city; (2) In the evaluation of green economy development, the order of importance of the three criterion layers is X1 Economy development > X2 Social livelihood of the people > X3 Resources and environment; (3) Local governments should implement differential, reasonable policies in order to improve their green economy development. Moreover, our research is not only significant for developing green economy in China’s sub-provincial cities, but also serves as a reference for the development of green economy in other cities in the world

A Novel Approach for Reducing Attributes and Its Application to Small Enterprise Financing Ability Evaluation

Attribute reduction is viewed as a kind of preprocessing steps for reducing large dimensionality in data mining of all complex systems. A great deal of researchers have proposed various approaches to reduce attributes or select key features in multicriteria decision making evaluation. In practice, the existing approaches for attribute reduction focused on improving the classification accuracy or saving the cost of computational time, without considering the influence of the reduction results on the original data set. To help address this gap, we develop an advanced novel attribute reduction approach combining Pearson correlation analysis with F test significance discrimination for the screening and identification of key characteristics related to the original data set. The proposed model has been verified using the financing ability evaluation data of 713 small enterprises of a city commercial bank in China. And the experimental results show that the proposed reduction model is efficient and effective. Moreover, our experimental findings help to locate the qualified partners and alleviate the difficulties faced by enterprises when applying loan

Clarification on the Internal Structure of Landslide Dam by Microtremor array survey method

The Tenth International Symposium on Mitigation of Geo-disasters in Asia Matsue Symposium Place: Shimane Civil Center, Matsue Date: 8 October 201

Study on the influence of liquid nitrogen injection cooling in gob on the thermal physical characteristics of coal spontaneous combustion

In order to study the effect of liquid nitrogen injection cooling on spontaneous combustion of coal, coal samples from the second and third panel areas of Tingnan Coal Mine were selected for thermal and physical property experiments. First, the coal sample was pretreated by LFA457 laser flash analyzer, and then the thermophysical property parameters of the coal sample were measured in the range of 30-300 ℃, and the change law of the thermophysical property parameters of the coal sample with temperature was obtained after liquid nitrogen injection and cooling, and the factors affecting the thermophysical properties of the coal sample were compared and analyzed. The results show that the thermal diffusivity decreases with the increase of temperature, and the specific heat capacity and thermal conductivity increase with the increase of temperature; in the range of 30-200 ℃, the average change rate of thermal property parameters of coal samples after liquid nitrogen injection treatment is higher than that of raw coal samples, indicating that liquid nitrogen injection treatment will increase the sensitivity of coal samples to temperature; in addition, at the same temperature, the thermal physical property parameters of coal samples after liquid nitrogen injection treatment increased to different degrees compared with the original coal samples, and the average growth rate of thermal diffusion coefficient was the highest, indicating that the thermal diffusion ability of coal samples after liquid nitrogen injection treatment was enhanced during the oxidation and heating process

Resveratrol ameliorates triglyceride accumulation through FXR deacetylation in high glucose-treated HepG2 cells

Hepatic lipid accumulation promotes the development of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes mellitus (T2DM). However, the underlying mechanism remains unclear. Sirt1, an NAD+-dependent histone deacetylase, plays a crucial role in NAFLD pathogenesis by regulating glycolipid metabolism. This study aims to evaluate the hepatoprotective effects and underlying mechanisms of resveratrol in T2DM-induced hepatic lipid accumulation. In vitro analysis of Sirt1 expression was conducted in high glucose (HG) -cultured HepG2 cells. It was observed that resveratrol (20 μM) significantly counteracted the triglyceride deposition and lipid droplet accumulation induced by the silencing of Sirt1. Further mechanistic studies attributed this benefit to the inhibition of FXR acetylation through upregulation of Sirt1. Notably, this hepatoprotective effect was abrogated upon the silencing of FXR. Overall, resveratrol reduced HG-induced lipid deposition by regulating the Sirt1-mediated deacetylation of FXR. The findings support the clinical potential of resveratrol in managing or preventing T2DM-induced hepatic steatosis