scholarly journals Effect of Rainfall, Runoff and Infiltration Processes on the Stability of Footslopes

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1229
Author(s):  
Hung-En Chen ◽  
Yen-Yu Chiu ◽  
Tung-Lin Tsai ◽  
Jinn-Chuang Yang

To analyze the effect of runoff on shallow landslides, a model coupling one-dimensional rainfall–runoff and two-dimensional infiltration was established to simulate rainfall, infiltration, and runoff processes. Based on Bishop’s limit equilibrium method, the slope failure of a hypothetical footslope was studied. First, conditions with and without inflow were compared. The results reveal a remarkable difference in factors of safety (FS) between the two conditions, suggesting that considering the effect of runoff is crucial for landslide modeling. In terms of a series of tests of the various magnitudes, durations, lag-time, and peak position of the hydrograph, analyses show that larger inflow leads to more accumulated infiltration and triggers landslides earlier. A long-term duration inflow decreases the stability more than short intensive inflow does. With subsequent surface inflow, slope failure may occur after rainfalls stop, owing to the inflow, and the shape of inflow hydrographs could slightly affect the variance in FS. Results also indicate the necessity of considering the surface runoff when using a numerical model to analyze landslide, particularly on a footslope.

2012 ◽  
Vol 152-154 ◽  
pp. 802-808
Author(s):  
Fei Zhang ◽  
Jing Cao ◽  
Ming Chen ◽  
Lei Peng

Combining the explicit Lagrangian difference method for the continuum body and strength reduction technology, this paper analyzed the stability of Xian Feng open-pit. The generalized shear strain and plastic strain interconnected within the weak structural plane of slope are used as criterion to identify slope failure state. Analysis of the example verifies that the criterion is rational. With the calculate model, it can predict the open-pit ultra-high slope stability after five years. Its results are similar to the traditional limit equilibrium method. Therefore, the method is reasonably practicable. So the result will be important significance to guide the post-construction of mine.


2012 ◽  
Vol 170-173 ◽  
pp. 1991-1995
Author(s):  
Lin Xiang Pang ◽  
Lan Qiao ◽  
Yuan Li

There are corresponding stability criterions for limit equilibrium method, which is simple to implement and has been used for long-term. But this method is only considered the equilibrium of system without considering deformation, compatibility conditions and material constitutive. To improve the method, which is used to analysis the stability of Lanna dam, was proposed to optimize the boundary conditions, consider the discontinuity between the media in junction and add additional stress to consider the effects of buoyancy and seepage. After completion, tests showed that this approach could overcome limit equilibrium method’s shortcoming and describe the discontinuous characteristics of media naturally, such as dislocation, opening, slip and so on. And the result is reliable.


2013 ◽  
Vol 671-674 ◽  
pp. 245-250
Author(s):  
Wen Hui Tan ◽  
Ya Liang Li ◽  
Cong Cong Li

At present, in-situ stress was not considered in Limit Equilibrium Method (LEM) of slopes, the influence of in-situ stress is very small on the stability of conventional slopes, but in deep-depressed open-pit mines, the influence should not be neglected. Formula for calculating the Factor of Safety (FOS) under the effect of horizontal in-situ stress was deduced using General Slice Method (GSM) of two-dimensional (2D) limit equilibrium method in this paper,a corresponding program SSLOPE was built, and the software was used in a deep- depressed open-pit iron mine. The results show that the FOS of the slope decreased by 20% when horizontal in-situ stress is considered, some reinforcements must be taken. Therefore, the influence of in-situ stress on slope stability should be taken into account in deep open –pit mines.


1983 ◽  
Vol 20 (4) ◽  
pp. 661-672 ◽  
Author(s):  
R. K. H. Ching ◽  
D. G. Fredlund

Several commonly encountered problems associated with the limit equilibrium methods of slices are discussed. These problems are primarily related to the assumptions used to render the inherently indeterminate analysis determinate. When these problems occur in the stability computations, unreasonable solutions are often obtained. It appears that problems occur mainly in situations where the assumption to render the analysis determinate seriously departs from realistic soil conditions. These problems should not, in general, discourage the use of the method of slices. Example problems are presented to illustrate these difficulties and suggestions are proposed to resolve these problems. Keywords: slope stability, limit equilibrium, method of slices, factor of safety, side force function.


2013 ◽  
Vol 405-408 ◽  
pp. 576-579
Author(s):  
Yong Hua Cao ◽  
Chuan Zhi Huang

The reliability theory based analysis is more advanced and reasonable compared with the traditional methods for slope stability analysis. Limit equilibrium method is usually used to evaluate the stability of a slope. In this paper, a new reliability analysis method is obtained based on JC method and multi sliding surface method which a new limit equilibrium method developed by Huang. Then, this new method is applied for a wharf slope. The sliding surface get from the safety factor is not the same as that from reliability index though they are close to each other. The safety factor or reliability index get from Fellenius method is smaller than that from other method. The safety factor or reliability index get from multi sliding surface method is close to that from Bishops method. The reliability index can be more reasonable after the standard deviation of the soil property index is deduced with random field theory.


2012 ◽  
Vol 166-169 ◽  
pp. 2535-2538
Author(s):  
Ke Wang ◽  
Chang Ming Wang ◽  
Fang Qi ◽  
Cen Cen Niu

The traditional limit equilibrium method in the analysis of slope stability not only exists some subjective empirical hypothesis that can not meet the equilibrium of force and moment, but also ignores the effects of internal stress and strain on the slope stability. Furthermore, in the stability of the slope evaluation, limit equilibrium method relies too much on experience when hypothesizing the slope slip surface. So that it makes deviation on slope analysis and stability evaluation. This paper is based on simplified Bishop method used to establish the model of slope stability analysis. And it used genetic algorithms to solve the minimum safety factor and the most dangerous slip surface of slope. It was the arithmetic which simulates organisms genetic evolutionary process and it avoided the traditional methods falling into the local extreme value point easily and error propagation leading to convergence. The algorithm had advantages of higher accuracy, quick convergence and applicability. It showed that the genetic algorithm is accurate and reliable in the analysis of slope stability.


2021 ◽  
Author(s):  
Tesfay Kiros Mebrahtu ◽  
Thomas Heinze ◽  
Stefan Wohnlich

<p>Landslides and ground failures are among the common geo-environmental hazards in many of the tectonically active hilly and mountainous terrains of Ethiopia, such as in the western margin of the Main Ethiopian Rift in Debre Sina area. Besides the geological preconditioning, bi-modal monsoon and seismic events in the tectonically highly active region are usually suspected triggers. In order to minimize the damage caused by the slope failure events, a detailed investigation of landslide-prone areas using numerical modelling plays a crucial role. The aim of this study is to assess the stability of slopes, to understand the relevant failure mechanisms, and to evaluate and compare safety factors calculated by the different available numerical methods. The stability was assessed for slopes of complex geometry and heterogeneous material using the limit equilibrium method and the shear strength reduction method based on finite elements. Furthermore, numerical analysis was done under static and pseudo-static loading using the horizontal seismic coefficient to model their stability during a seismic event. The slope stability analysis indicates that the studied slopes are unstable, and any small scale disturbance will further reduce the factor of safety and probably causing failure. The critical strength reduction factors from the finite element method are significantly lower than the factor of safety from the limit equilibrium method in all studied scenarios, such as Bishop, Janbu Simplified, Spencer and Morgenstern-Price. The difference is especially evident for heterogeneous slopes with joints, which often are initiation points for the failure planes. The simulations show that slope stability of landslide prone hills in the study area strongly depends on the saturation conditions and the seismic load. The studied slopes are initially close to failure and increased pore-pressure or seismic load are very likely triggers.</p>


2013 ◽  
Vol 671-674 ◽  
pp. 180-185
Author(s):  
Qing Wang ◽  
Lei Hua Yao ◽  
Ning Zhang

Xiufengsi Landslide is an ancient landslide in Wushan County, Chongqing, China. Under natural condition, this landslide is stable. Due to the Three Gorges Reservoir, however, the water level in this region fluctuates within the range of [145 m, 175 m], periodically. Furthermore, an increasing number of residential quarters have been built on this landslide that also increase the possibility of occurrences of the landslide. Motivated by the government’s desire to take measures in control the landslide, we use two approaches to study the stability of this landslide. Under different computational conditions, the safety factors of the landslide are calculated by using limit equilibrium method and finite element method, respectively. Based on the comparison of the results, the stability of the landslide is analyzed more objectively and comprehensively. This work also lends insight into the landslide forecast.


2018 ◽  
Vol 386 ◽  
pp. 75-79
Author(s):  
Nikolay G. Galkin ◽  
Dmitrii Tkhyarbonovich Yan ◽  
Konstantin N. Galkin ◽  
Evgeniy Anatolievich Chusovitin ◽  
Mikhail Victorovich Bozhenko

In the process of comparative studies of immersing layers of porous silicon (PS) in aqueous solutions of LiBr and Fe (NO3)3 with subsequent long-term storage up to 150 days, it is established that there exists: (1) the range of concentrations of LiBr (S/2 - S/4) and Fe (NO3)3 (0.2 M), which provide the maximum increase in the intensity of PL; (2) at low concentrations of both salts, a blue shift of the PL peaks and an increase in their intensity are observed during the long-term storage, which is associated with a decrease in the size of the NC in the PS and the influence of silicon bonds with lithium or iron ions; (3) full protection of the PS layer is observed in case of immersion in Fe (NO3)3 with a concentration of 0.7M - 0.8M.


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