The Taihang Mountains area is an area in North China where serious mudflow hazards take place frequently. The hazards often obstrust traffic and make it difficult to carry out conventional ground investigations of the...The Taihang Mountains area is an area in North China where serious mudflow hazards take place frequently. The hazards often obstrust traffic and make it difficult to carry out conventional ground investigations of the mudflow hazards. This paper introduces the feasibility study of mudflow hazards by using Landsat-5TM data. The study has achieved a great success through adopting both the faint spectral enhancement technique for mudflow fans (or other depositional areas) and comprehensive study of the environmental background of pregnant mudflows. Thus, remote sensing as a fast, convenient, low-cost and effective technical method can be used to recognise the situation of mudflow hazards so that effective rescue can be provided.展开更多
The structure of loess is loose,and the shear strength of loess drops sharply after contact with water.Therefore,loess mudflows have become a common geological disaster on the Chinese Loess Plateau.In order to study t...The structure of loess is loose,and the shear strength of loess drops sharply after contact with water.Therefore,loess mudflows have become a common geological disaster on the Chinese Loess Plateau.In order to study the initiation mode and mechanism of loess mudflows,in this study,seven sets of flume experiments were designed by controlling the slope angle and rainfall intensity.The results show that(1)when the slope angle is between 10°and 20°,there are two initiation mechanisms of loess mudflows:mudflow(large scale)and retrogressive toe sliding,and mudflow(small-scale)and retrogressive toe sliding.(2)The main method by which water infiltrates into the soil accumulation is mainly vertical infiltration,which is not affected by the slope angle and the seepage direction of the accumulation soil.(3)The liquefaction of loess is the root cause of loess mudflows.Water infiltrates into the area with an uneven density and a large amount of water accumulates in this area.Thus,the water content of the loess increases and the pore water pressure increases quickly and cannot dissipate in time,so the loess liquefies and the liquefacted area continues to spread and become larger.Thus,loess mudflows(large scale)occur.The increase in pore water pressure was captured in the seven sets of experiments.However,the order of the rising positions in the accumulation were different.This requires us to carry out tracking of the particle displacement inside the soil and the spatial changes in the internal structure of the soil in future research.展开更多
The paper presents the results of the field and laboratory research carried out in the Chokheltkhevi river basin, according to which the sediment-forming solid mass accumulated in the bed of the Chokhelthkhevi river w...The paper presents the results of the field and laboratory research carried out in the Chokheltkhevi river basin, according to which the sediment-forming solid mass accumulated in the bed of the Chokhelthkhevi river was recorded and its granulometric and chemical composition, as well as physical-mechanical characteristics, were studied. Based on the results of the research, it can be said that in the debrisflow channel of the Chokheltkhevi River, coarse and sandy-clay soils are mainly accumulated, which represent an unstable mass for the expected debrisflow in the gorge, which, together with other geological, hydrological and climatic factors, helps to increase the scale of the expected ecological danger. According to the results of the laboratory research, it can be concluded that the soil accumulated in the drainage channel is low in ion concentration, and the humus content in it is minimal, which indicates the possibility of easy displacement of the solid mass accumulated in the drainage channel and, accordingly, the risk of a catastrophic debrisflow.展开更多
文摘The Taihang Mountains area is an area in North China where serious mudflow hazards take place frequently. The hazards often obstrust traffic and make it difficult to carry out conventional ground investigations of the mudflow hazards. This paper introduces the feasibility study of mudflow hazards by using Landsat-5TM data. The study has achieved a great success through adopting both the faint spectral enhancement technique for mudflow fans (or other depositional areas) and comprehensive study of the environmental background of pregnant mudflows. Thus, remote sensing as a fast, convenient, low-cost and effective technical method can be used to recognise the situation of mudflow hazards so that effective rescue can be provided.
基金financially supported by the Program of National Natural Science Foundation of China(Nos.42090053,42041006,4210071970)Central University Fundamental Research Fund(No.300102262907)。
文摘The structure of loess is loose,and the shear strength of loess drops sharply after contact with water.Therefore,loess mudflows have become a common geological disaster on the Chinese Loess Plateau.In order to study the initiation mode and mechanism of loess mudflows,in this study,seven sets of flume experiments were designed by controlling the slope angle and rainfall intensity.The results show that(1)when the slope angle is between 10°and 20°,there are two initiation mechanisms of loess mudflows:mudflow(large scale)and retrogressive toe sliding,and mudflow(small-scale)and retrogressive toe sliding.(2)The main method by which water infiltrates into the soil accumulation is mainly vertical infiltration,which is not affected by the slope angle and the seepage direction of the accumulation soil.(3)The liquefaction of loess is the root cause of loess mudflows.Water infiltrates into the area with an uneven density and a large amount of water accumulates in this area.Thus,the water content of the loess increases and the pore water pressure increases quickly and cannot dissipate in time,so the loess liquefies and the liquefacted area continues to spread and become larger.Thus,loess mudflows(large scale)occur.The increase in pore water pressure was captured in the seven sets of experiments.However,the order of the rising positions in the accumulation were different.This requires us to carry out tracking of the particle displacement inside the soil and the spatial changes in the internal structure of the soil in future research.
文摘The paper presents the results of the field and laboratory research carried out in the Chokheltkhevi river basin, according to which the sediment-forming solid mass accumulated in the bed of the Chokhelthkhevi river was recorded and its granulometric and chemical composition, as well as physical-mechanical characteristics, were studied. Based on the results of the research, it can be said that in the debrisflow channel of the Chokheltkhevi River, coarse and sandy-clay soils are mainly accumulated, which represent an unstable mass for the expected debrisflow in the gorge, which, together with other geological, hydrological and climatic factors, helps to increase the scale of the expected ecological danger. According to the results of the laboratory research, it can be concluded that the soil accumulated in the drainage channel is low in ion concentration, and the humus content in it is minimal, which indicates the possibility of easy displacement of the solid mass accumulated in the drainage channel and, accordingly, the risk of a catastrophic debrisflow.
