Rainfall Infiltration Process of a Rock Slope with Considering the Heterogeneity of Saturated Hydraulic Conductivity

In order to analyze the effects of rainfall events on the stability of an open-pit rock slope, with considering the spatial variability of saturated hydraulic conductivity, based on the unsaturated seepage theory and the random filed theory, modified functions of the unit saturation, the hydraulic conductivity (k), and the shear strength parameters are established for unsaturated slope, by using FISH and the non-intrusive stochastic method. A saturated-unsaturated seepage random field model is proposed. And then the impacts of the rainfall intensity, the rainfall duration, and the spatial variability of saturated hydraulic conductivity (ks) on the infiltration process and stability of the unsaturated rock slope are analyzed. The results show that the proposed model can estimate rainfall infiltration of rock slope accurately. Rainfall mainly affects the seepage field in the shallow layer of the slope, where a transient saturated zone can be formed. With the development of the rainfall duration, the weight of the rock mass increased, the matric suction reduced, the negative pore pressure, the degree of saturation, and the infiltration depth of the rock slope increased, and the water in the slope root connects with the initial water table gradually, the unsaturated zone shrinks, which causes the safety factor of the model decreases, but the trend of change slows down gradually. As the rainfall intensity strengthened, the infiltration depth increased and the safety factor of the slope reduced, while the changing rate increases first and then decreases. Increasing the correlation length of k can reduces the infiltration depth and safety factor of the slope. Increasing the variation coefficient of k will increase the infiltration depth, while the safety factor of the slope decreases. The infiltration depth and safety factor of the slope are most affected by rainfall duration, but its sensitivity to the variability coefficient of k will be strengthened when the rainfall intensity exceeds the infiltration capacity. This conclusion can provide reference significance for the risk estimation of slope geological hazards, which are induced by the rainfall infiltration.

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Research of Slope Stability Analysis Considering Rainfall Infiltration

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.487 ◽

2012 ◽

Vol 204-208 ◽

pp. 487-491

Author(s):

Jian Hua Liu ◽

Zhi Min Chen ◽

Wei He

Keyword(s):

Slope Stability ◽

Pore Water ◽

Rock Slope ◽

Rainfall Intensity ◽

Pore Water Pressure ◽

Water Pressure ◽

Rainfall Infiltration ◽

Safety Coefficient ◽

Rainfall Duration ◽

Unsaturated Seepage

Based on the saturated-unsaturated seepage theory and considering soil-hydraulic permeability coefficient characteristic curves of rock slope, the variation of suction in unsaturated region and transient saturated zone formation of rock slope were analyzed. Combined with engineering example, the strength reduction methods were adopted to analyzing the rock slope stability influence factors considering unsaturated seepage with different rainfall intensity and duration. The results show that the flow domain owing to rainfall infiltration mainly appears surface layer region of slope. The rainfall infiltration caused the groundwater level rise, the rising of transient pore water pressure and the fall of suction in unsaturated region caused the slope stability decrease. The rainfall intensity and duration have obvious influence on slope stability, and in the same rainfall duration condition, the safety coefficient of slope decreases with the accretion of rainfall intensity. With the rainfall duration increasing, the water in soil has more deep infiltration, the water content and pore water pressure was higher in the same high position, the decreasing of suction caused the safety coefficient of slope has more reduce.

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Influence of Spatial Variability of Saturated Hydraulic Conductivity on the Infiltration Process

Unsaturated Flow in Hydrologic Modeling ◽

10.1007/978-94-009-2352-2_17 ◽

1989 ◽

pp. 455-467 ◽

Cited By ~ 1

Author(s):

Paulo Matias ◽

Francisco Nunes Correia ◽

Luís Santos Pereira

Keyword(s):

Hydraulic Conductivity ◽

Spatial Variability ◽

Saturated Hydraulic Conductivity ◽

Infiltration Process

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Infinite Slope Stability under Transient Rainfall Infiltration Conditions

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.501-504.395 ◽

2014 ◽

Vol 501-504 ◽

pp. 395-398 ◽

Cited By ~ 1

Author(s):

Yu Fei Kong ◽

Jian Liu ◽

Hong Gang Shi ◽

Long Ying Zhang ◽

Heng Zhao ◽

...

Keyword(s):

Stability Analysis ◽

Slope Stability ◽

Safety Factor ◽

Underground Water ◽

Rainfall Infiltration ◽

Infiltration Process ◽

Infinite Slope ◽

Seepage Analysis ◽

Infiltration Model ◽

Two Stages

The infiltration process of infinite slopes was studied with modified Green-Ampt infiltration model. The process was divided into two stages, in which the depth of the wetting zone and underground water was calculated. Stability analysis considering different sliding patterns was conducted on the basis of seepage analysis. The safety factor of infinite slopes at different time stages has been derived. Equations in this paper could be used for predicting rain-induced landslides with limited parameters available.

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Improved calibration of the Green–Ampt infiltration module in the EROSION-2D/3D model using a rainfall-runoff experiment database

SOIL ◽

10.5194/soil-7-241-2021 ◽

2021 ◽

Vol 7 (1) ◽

pp. 241-253

Author(s):

Hana Beitlerová ◽

Jonas Lenz ◽

Jan Devátý ◽

Martin Mistr ◽

Jiří Kapička ◽

...

Keyword(s):

Soil Moisture ◽

Hydraulic Conductivity ◽

Soil Erosion ◽

3D Model ◽

Transfer Functions ◽

State Of The Art ◽

The State ◽

Saturated Hydraulic Conductivity ◽

Infiltration Process ◽

Calibration Parameter

Abstract. Soil infiltration is one of the key factors that has an influence on soil erosion caused by rainfall. Therefore, a well-represented infiltration process is a necessary precondition for successful soil erosion modelling. Complex natural conditions do not allow the full mathematical description of the infiltration process, and additional calibration parameters are required. The Green–Ampt-based infiltration module in the EROSION-2D/3D model introduces a calibration parameter “skinfactor” to adjust saturated hydraulic conductivity. Previous studies provide skinfactor values for several combinations of soil and vegetation conditions. However, their accuracies are questionable, and estimating the skinfactors for other than the measured conditions yields significant uncertainties in the model results. This study brings together an extensive database of rainfall simulation experiments, the state-of-the-art model parametrisation method and linear mixed-effect models to statistically analyse relationships between soil and vegetation conditions and the model calibration parameter skinfactor. New empirically based transfer functions for skinfactor estimation significantly improving the accuracy of the infiltration module and thus the overall EROSION-2D/3D model performance are provided in this study. Soil moisture and bulk density were identified as the most significant predictors explaining 82 % of the skinfactor variability, followed by the soil texture, vegetation cover and impact of previous rainfall events. The median absolute percentage error of the skinfactor prediction was improved from 71 % using the currently available method to 30 %–34 % using the presented transfer functions, which led to significant decrease in error propagation into the model results compared to the present method. The strong logarithmic relationship observed between the calibration parameter and soil moisture however indicates high overestimation of infiltration for dry soils by the algorithms implemented in EROSION-2D/3D and puts the state-of-the-art parametrisation method in question. An alternative parameter optimisation method including calibration of two Green–Ampt parameters' saturated hydraulic conductivity and water potential at the wetting front was tested and compared with the state-of-the-art method, which paves a new direction for future EROSION-2D/3D model parametrisation.

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The Unsaturated Hydromechanical Coupling Model of Rock Slope Considering Rainfall Infiltration Using DDA

Geofluids ◽

10.1155/2017/1513421 ◽

2017 ◽

Vol 2017 ◽

pp. 1-15 ◽

Cited By ~ 3

Author(s):

Xianshan Liu ◽

Ming Xu

Keyword(s):

Water Flow ◽

Rock Slope ◽

Rainfall Intensity ◽

Water Pressure ◽

Great Influence ◽

Coupling Model ◽

Rainfall Infiltration ◽

Discontinuous Deformation Analysis ◽

Reservoir Rock ◽

Hydromechanical Coupling

Water flow and hydromechanical coupling process in fractured rocks is more different from that in general porous media because of heterogeneous spatial fractures and possible fracture-dominated flow; a saturated-unsaturated hydromechanical coupling model using a discontinuous deformation analysis (DDA) similar to FEM and DEM was employed to analyze water movement in saturated-unsaturated deformed rocks, in which the Van-Genuchten model differently treated the rock and fractures permeable properties to describe the constitutive relationships. The calibrating results for the dam foundation indicated the validation and feasibility of the proposed model and are also in good agreement with the calculations based on DEM still demonstrating its superiority. And then, the rainfall infiltration in a reservoir rock slope was detailedly investigated to describe the water pressure on the fault surface and inside the rocks, displacement, and stress distribution under hydromechanical coupling conditions and uncoupling conditions. It was observed that greater rainfall intensity and longer rainfall time resulted in lower stability of the rock slope, and larger difference was very obvious between the hydromechanical coupling condition and uncoupling condition, demonstrating that rainfall intensity, rainfall time, and hydromechanical coupling effect had great influence on the saturated-unsaturated water flow behavior and mechanical response of the fractured rock slopes.

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Physical Model Test Study of the Relationship Between Loess Landslide and Rainfall

The Open Civil Engineering Journal ◽

10.2174/1874149501509010968 ◽

2015 ◽

Vol 9 (1) ◽

pp. 968-973

Author(s):

Jiaming Han

Keyword(s):

Moisture Content ◽

Safety Factor ◽

Model Test ◽

Rainfall Intensity ◽

Unit Weight ◽

Loess Landslide ◽

Rainfall Duration ◽

Loess Slope ◽

Test Study ◽

The Relationship

Launching research has important theoretical and practical value on model test study of the relationship between loess landslide and rainfall. According to the monitoring data of model test of loess slope, formula expression of safety factor has been fitted on landslide. Firstly, the loess slope damage process was monitored at different rainfall intensity, rainfall duration through rainfall landslide model tests. Secondly, some parameters were determined by laboratory tests, such as loess unit weight, moisture content, shear strength. Thirdly, the relational expression was fitted between moisture and rainfall intensity, rainfall duration, cohesion, internal friction angle, unit weight. Finally, moisture content being an intermediate variable, the expression was got between landslide safety factor and rainfall intensity, rainfall duration.

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A Simulation of Salt Transport in NaCl-Laden Soil Barrier to Control Subterranean Termites in an Earth Embankment

Water ◽

10.3390/w13091204 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1204

Author(s):

Ying Li ◽

Dong-Zi Pan

Keyword(s):

Hydraulic Conductivity ◽

Saturated Hydraulic Conductivity ◽

Rainfall Infiltration ◽

Salt Transport ◽

Subterranean Termite ◽

Water Level Fluctuations ◽

Subterranean Termites ◽

Promising Alternative ◽

Earth Embankment

Subterranean termite activity can increase the hydraulic conductivity and water infiltration of filling soil, and therefore affects the stability of an earth embankment and subsequent safety. As a physical barrier for sustainable termite management, NaCl-laden soil barrier (NLSB) is a promising alternative for subterranean termite control in earth embankments. This novel technology can prevent tunneling and penetration of subterranean termites into the interior of an embankment and has been widely employed for more than 20 years in Zhejiang Province, China. The efficacy and longevity of NLSB depend on the long-term presence of NaCl concentration in soil barriers. The aim of this study is to develop an understanding of water flow and salt transport in NLSB based on the two-dimensional Richards’ equation and convection dispersion equation using the HYDRUS software package. Conceptual and numerical models of NLSB are modeled using scenario analysis according to water level fluctuations, saturated hydraulic conductivity, and rainfall infiltration conditions. Furthermore, the center and spread variance of a solute mass over a 100-year period are quantified using moment analysis. As flood frequency, saturated hydraulic conductivity, and rainfall infiltration flux increase, salt desalination in NLSB significantly increases. When the rainfall infiltration flux is 1% of the annual average rainfall, the total amount of salt transport and leaching can increase by 55%. Moreover, these results facilitate better long-term sustainable management of existing sites and optimal design of future NLSBs.

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A Simplified Falling-Head Technique for Rapid Determination of Field-Saturated Hydraulic Conductivity

Soil Science Society of America Journal ◽

10.2136/sssaj2004.0066 ◽

2004 ◽

Vol 68 (1) ◽

pp. 66 ◽

Cited By ~ 17

Author(s):

V. Bagarello ◽

M. Iovino ◽

D. Elrick

Keyword(s):

Hydraulic Conductivity ◽

Rapid Determination ◽

Saturated Hydraulic Conductivity

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Saturated Hydraulic Conductivity of Clayey Tills and the Role of Fractures

Hydrology Research ◽

10.2166/nh.1990.0009 ◽

1990 ◽

Vol 21 (2) ◽

pp. 119-132 ◽

Cited By ~ 48

Author(s):

Johnny Fredericia

Keyword(s):

Hydraulic Conductivity ◽

American Studies ◽

Field Measurements ◽

Present Knowledge ◽

Saturated Hydraulic Conductivity ◽

Field Observations ◽

Laboratory Measurements ◽

Vertical Hydraulic Conductivity ◽

Data Field

The background for the present knowledge about hydraulic conductivity of clayey till in Denmark is summarized. The data show a difference of 1-2 orders of magnitude in the vertical hydraulic conductivity between values from laboratory measurements and field measurements. This difference is discussed and based on new data, field observations and comparison with North American studies, it is concluded to be primarily due to fractures in the till.

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