scholarly journals Slope Stability from a Hydrological Perspective: Taking Typical Soil Slope as an Example

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Yuelu Zhu ◽  
Yaoting Xiao
Keyword(s):  
Shear Strength ◽  
Soil Moisture ◽  
Moisture Content ◽  
Slope Stability ◽  
Soil Moisture Content ◽  
Stable State ◽  
Temporal Distribution ◽  
Stability Factor ◽  
Infiltration Capacity ◽  
Increasing Trend

In the traditional research of slope stability, it is difficult to continuously obtain the moisture content of soil in long time sequences. In combination with the precipitation, temperature, and vegetation cover data in the study area, the variable infiltration capacity hydrological model is used to estimate the daily variation of soil moisture content, which is used as a calculation condition for the analysis of slope stability. The results show that, from 1970 to 2010, the spatial-temporal distribution of soil moisture content in the Weihe River Basin showed an increasing trend. Moreover, the shear strength of soil decreased, but the range was stable at approximately 2%. The strength reduction method based on the M-C inscribed circle criterion (DP3) shows that the slope stability factor k had an increasing trend for over 40 y. The portion of the period with a k value higher than 1.2 is more than 85% of the entire period, that with a k value between 1 and 1.2 is approximately 9%, and that with a k value less than 1 is approximately 5.5%. The R/S analysis results show that the Hurst coefficients of the τ-t curve and the k-t curve are 0.5568 and 0.5888, respectively, and that the slope is in a state of no variation. Based on these factors, the present and future of the slope is in a stable state. This scheme is a method of studying slope stability based on hydrology, and it provides a modern alternative for soil shear strength calculation and geological hazard assessment.

scholarly journals Experimental Study on Shear Resistance of Carex-Root-Fibered Soil

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Feng-Chi Wang ◽  
Ming-Ze Zhao ◽  
Qi Sun
Keyword(s):  
Shear Strength ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Friction Angle ◽  
Fiber Content ◽  
Soil Consolidation ◽  
And Performance ◽  
The Relationship ◽  
Root Fiber

Carex shows strong vitality, adaptability, and performance with regard to soil consolidation and slope protection but is often disregarded as a weed. This study proposes to turn this so-called weed into treasure, using its characteristics to protect the slope. We studied the interaction between the carex roots and soil and compared it to other types of grass. To understand the interaction between the carex roots and soil, this study investigated the tensile properties of the carex root fibers. The effects of fiber content, humidity, distribution, and soil moisture content on the relationship between the shear strength and vertical pressure of the soil were analyzed using a direct shear test. Furthermore, the cohesion and internal friction angle were used to evaluate the shear strength of the root-fibered soil based on Mohr–Coulomb’s law. The results showed that the smaller the diameter, the shorter the length, and the greater the quantity and the lower the humidity of the root fibers, the higher the tensile strength of root fibers. In addition, the soil strength could be improved by the joint action of the roots and the soil. With an increase in the root fiber content and humidity, the soil moisture content decreased, whereas the shear strength of the carex-root-fibered soil increased. Here, four kinds of root fiber distributions, namely, “glyph,” “herringbone,” “eccentric,” and “vertical,” were chosen to study the shear strength of the root-fibered soil. The results showed that “glyph” root fiber distribution had the highest shear strength, while the shear strength decreased for the others.

Constitutive Model of Shallow Landslides Catastrophe Theory under the Heavy Rainfall

2012 ◽  
Vol 166-169 ◽  
pp. 2718-2721
Author(s):  
Sheng Guo Cheng ◽  
Hong Zheng
Keyword(s):  
Shear Strength ◽  
Soil Moisture ◽  
Moisture Content ◽  
Constitutive Model ◽  
Catastrophe Theory ◽  
Heavy Rainfall ◽  
Soil Moisture Content ◽  
Shallow Landslide ◽  
Landslide Stability ◽  
Function Relationship

Heavy rainfall has important implications to shallow landslide stability. In the paper, the relationship between the soil moisture content and soil shear strength and between surface displacements of landslide and rainfall were studied. Their statistical relationships were established. Relationship between soil moisture content and shear strength should be fitted using the logarithmic function. Relationship between soil slope and rainfall displacement should adopt the power function fit. Constitutive model of catastrophe theory of heavy rainfall landslides stability was known, which it is very important to provide a theoretical basis for prediction.

Impacts of soil moisture content and vegetation on shear strength of unsaturated soil

2005 ◽  
Vol 10 (4) ◽  
pp. 682-688 ◽  
Author(s):  
Yang Yong-hong ◽  
Zhang Jian-guo ◽  
Zhang Jian-hui ◽  
Liu Shu-zhen ◽  
Wang Cheng-hua ◽  
...  
Keyword(s):  
Shear Strength ◽  
Soil Moisture ◽  
Moisture Content ◽  
Unsaturated Soil ◽  
Soil Moisture Content

scholarly journals Effects of Vegetation Restoration on Regional Soil Moisture Content in the Humid Karst Areas—A Case Study of Southwest China

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 321
Author(s):  
Xiaocha Wei ◽  
Qiuwen Zhou ◽  
Mingyong Cai ◽  
Yujuan Wang
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Southwest China ◽  
Vegetation Restoration ◽  
Data Set ◽  
Karst Areas ◽  
Increasing Trend ◽  
Drying Trend

Soil moisture is one of the restricting factors in the humid karst areas, which feature strong spatial heterogeneity. However, current research about the effects of vegetation restoration on soil moisture content have mainly focused on plot scale and slope scale, while these effects still remain unclear at regional scale in this area. Taking Southwest China as a case study and based on the land parameter data record (LPDR) and enhanced vegetation index (EVI) data set during 2002–2018, this study analyzed the spatiotemporal variation characteristics of vegetation and soil moisture content, and evaluated the effects of vegetation restoration on regional soil moisture content dynamics in paired years with similar precipitation conditions. The results showed that the EVI generally increased at a rate of 0.035/10a during 2002–2018, while the soil moisture was dominated by a drying trend at a variation rate of −0.0006 (cm3/cm3)/10a. The increasing trend of EVI accounted for 90.90% across the study area, whereas the decreasing trend of soil moisture accounted for 51.66%, and the increasing trend of soil moisture accounted for 48.34%. In addition, the decreasing trend of soil moisture coupled with an increasing trend of EVI distributed in most of the study area, especially in the homogenous limestone area. Our results demonstrate that there were remarkable vegetation restoration efforts in a series of ecological restoration projects, which resulted in a drying trend of the regional soil moisture content in the humid karst areas. The results suggest that it is necessary to consider reasonable vegetation planting density and suitable revegetation types to balance the relationship between vegetation water consumption and soil moisture supplementation in vegetation restoration practice in the humid karst areas.

Analysis on Soil Moisture Content in the Middle Reaches of the Yellow River

2011 ◽  
Vol 28 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Run-chun LI ◽  
Xiu-zhi ZHANG ◽  
Li-hua WANG ◽  
Xin-yan LV ◽  
Yuan GAO
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Yellow River ◽  
The Yellow River

Distribution of soil moisture content and its effect on the potential growth of the over-story species in North-East Chalkidiki

2001 ◽  
Vol 66 ◽  
Author(s):  
M. Aslanidou ◽  
P. Smiris
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Depth ◽  
Moisture Distribution ◽  
Taxus Baccata ◽  
Mixed Stands ◽  
Potential Growth ◽  
North East ◽  
Soil Moisture Distribution

This  study deals with the soil moisture distribution and its effect on the  potential growth and    adaptation of the over-story species in north-east Chalkidiki. These  species are: Quercus    dalechampii Ten, Quercus  conferta Kit, Quercus  pubescens Willd, Castanea  sativa Mill, Fagus    moesiaca Maly-Domin and also Taxus baccata L. in mixed stands  with Fagus moesiaca.    Samples of soil, 1-2 kg per 20cm depth, were taken and the moisture content  of each sample    was measured in order to determine soil moisture distribution and its  contribution to the growth    of the forest species. The most important results are: i) available water  is influenced by the soil    depth. During the summer, at a soil depth of 10 cm a significant  restriction was observed. ii) the    large duration of the dry period in the deep soil layers has less adverse  effect on stands growth than in the case of the soil surface layers, due to the fact that the root system mainly spreads out    at a soil depth of 40 cm iii) in the beginning of the growing season, the  soil moisture content is    greater than 30 % at a soil depth of 60 cm, in beech and mixed beech-yew  stands, is 10-15 % in    the Q. pubescens  stands and it's more than 30 % at a soil depth of 60 cm in Q. dalechampii    stands.

scholarly journals Mapping barrier island soil moisture using a radiative transfer model of hyperspectral imagery from an unmanned aerial system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rehman S. Eon ◽  
Charles M. Bachmann
Keyword(s):  
Soil Moisture ◽  
Radiative Transfer ◽  
Moisture Content ◽  
Layer Thickness ◽  
Soil Moisture Content ◽  
Hyperspectral Imagery ◽  
Barrier Island ◽  
Water Layer ◽  
Radiative Transfer Model ◽  
Transfer Model

AbstractThe advent of remote sensing from unmanned aerial systems (UAS) has opened the door to more affordable and effective methods of imaging and mapping of surface geophysical properties with many important applications in areas such as coastal zone management, ecology, agriculture, and defense. We describe a study to validate and improve soil moisture content retrieval and mapping from hyperspectral imagery collected by a UAS system. Our approach uses a recently developed model known as the multilayer radiative transfer model of soil reflectance (MARMIT). MARMIT partitions contributions due to water and the sediment surface into equivalent but separate layers and describes these layers using an equivalent slab model formalism. The model water layer thickness along with the fraction of wet surface become parameters that must be optimized in a calibration step, with extinction due to water absorption being applied in the model based on equivalent water layer thickness, while transmission and reflection coefficients follow the Fresnel formalism. In this work, we evaluate the model in both field settings, using UAS hyperspectral imagery, and laboratory settings, using hyperspectral spectra obtained with a goniometer. Sediment samples obtained from four different field sites representing disparate environmental settings comprised the laboratory analysis while field validation used hyperspectral UAS imagery and coordinated ground truth obtained on a barrier island shore during field campaigns in 2018 and 2019. Analysis of the most significant wavelengths for retrieval indicate a number of different wavelengths in the short-wave infra-red (SWIR) that provide accurate fits to measured soil moisture content in the laboratory with normalized root mean square error (NRMSE)< 0.145, while independent evaluation from sequestered test data from the hyperspectral UAS imagery obtained during the field campaign obtained an average NRMSE = 0.169 and median NRMSE = 0.152 in a bootstrap analysis.

scholarly journals Estimating Agricultural Soil Moisture Content through UAV-Based Hyperspectral Images in the Arid Region

2021 ◽  
Vol 13 (8) ◽  
pp. 1562
Author(s):  
Xiangyu Ge ◽  
Jianli Ding ◽  
Xiuliang Jin ◽  
Jingzhe Wang ◽  
Xiangyue Chen ◽  
...  
Keyword(s):  
Data Mining ◽  
Soil Moisture ◽  
Moisture Content ◽  
Hyperspectral Imaging ◽  
Fractional Order ◽  
Arid Regions ◽  
Soil Moisture Content ◽  
Order Derivative ◽  
Imaging Data ◽  
Strategy I

Unmanned aerial vehicle (UAV)-based hyperspectral remote sensing is an important monitoring technology for the soil moisture content (SMC) of agroecological systems in arid regions. This technology develops precision farming and agricultural informatization. However, hyperspectral data are generally used in data mining. In this study, UAV-based hyperspectral imaging data with a resolution o 4 cm and totaling 70 soil samples (0–10 cm) were collected from farmland (2.5 × 104 m2) near Fukang City, Xinjiang Uygur Autonomous Region, China. Four estimation strategies were tested: the original image (strategy I), first- and second-order derivative methods (strategy II), the fractional-order derivative (FOD) technique (strategy III), and the optimal fractional order combined with the optimal multiband indices (strategy IV). These strategies were based on the eXtreme Gradient Boost (XGBoost) algorithm, with the aim of building the best estimation model for agricultural SMC in arid regions. The results demonstrated that FOD technology could effectively mine information (with an absolute maximum correlation coefficient of 0.768). By comparison, strategy IV yielded the best estimates out of the methods tested (R2val = 0.921, RMSEP = 1.943, and RPD = 2.736) for the SMC. The model derived from the order of 0.4 within strategy IV worked relatively well among the different derivative methods (strategy I, II, and III). In conclusion, the combination of FOD technology and the optimal multiband indices generated a highly accurate model within the XGBoost algorithm for SMC estimation. This research provided a promising data mining approach for UAV-based hyperspectral imaging data.

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