Experimental Study on Slope Stability with Soil Mixed Rocks under Rainfall

2012 ◽  
Vol 170-173 ◽  
pp. 506-510
Author(s):  
Fang Cai Zhu ◽  
Yue Yang ◽  
Chun Ming Chen
Keyword(s):  
Experimental Study ◽  
Slope Stability ◽  
Water Content ◽  
Slope Failure ◽  
Western China ◽  
Laboratory Model ◽  
Small Scale ◽  
Loss Of Life ◽  
Key Factor ◽  
Scale Failure

Rainfall is a key factor that triggers failure of slopes. Due to development of western China, there are more and more slopes with soils mixed rocks, with rainfall effect, some of them will fail, which will lead to loss of life and property. In this paper, a laboratory model was used to simulate to study slope failure of this type under rainfall. Along with rainfall, water infiltrated into the slope, and water content increased steadily and kept almost constant, settlement of inner zone increased with different magnitude and reached almost constant value, and cracks formed on the top, small scale failure occurred.

scholarly journals Dealing with deep uncertainties in landslide modelling for disaster risk reduction under climate change

2017 ◽  
Vol 17 (2) ◽  
pp. 225-241 ◽  
Author(s):  
Susana Almeida ◽  
Elizabeth Ann Holcombe ◽  
Francesca Pianosi ◽  
Thorsten Wagener
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Numerical Models ◽  
Landslide Risk ◽  
Residual Soils ◽  
Loss Of Life ◽  
Economic Changes ◽  
Critical Thresholds ◽  
Stability Model ◽  
Steep Slopes

Abstract. Landslides have large negative economic and societal impacts, including loss of life and damage to infrastructure. Slope stability assessment is a vital tool for landslide risk management, but high levels of uncertainty often challenge its usefulness. Uncertainties are associated with the numerical model used to assess slope stability and its parameters, with the data characterizing the geometric, geotechnic and hydrologic properties of the slope, and with hazard triggers (e.g. rainfall). Uncertainties associated with many of these factors are also likely to be exacerbated further by future climatic and socio-economic changes, such as increased urbanization and resultant land use change. In this study, we illustrate how numerical models can be used to explore the uncertain factors that influence potential future landslide hazard using a bottom-up strategy. Specifically, we link the Combined Hydrology And Stability Model (CHASM) with sensitivity analysis and Classification And Regression Trees (CART) to identify critical thresholds in slope properties and climatic (rainfall) drivers that lead to slope failure. We apply our approach to a slope in the Caribbean, an area that is naturally susceptible to landslides due to a combination of high rainfall rates, steep slopes, and highly weathered residual soils. For this particular slope, we find that uncertainties regarding some slope properties (namely thickness and effective cohesion of topsoil) are as important as the uncertainties related to future rainfall conditions. Furthermore, we show that 89 % of the expected behaviour of the studied slope can be characterized based on only two variables – the ratio of topsoil thickness to cohesion and the ratio of rainfall intensity to duration.

scholarly journals Dynamic and Static Combination Analysis Method of Slope Stability Analysis during Earthquake

2014 ◽  
Vol 2014 ◽  
pp. 1-13
Author(s):  
Liang Lu ◽  
Zongjian Wang ◽  
Xiaoyuan Huang ◽  
Bin Zheng ◽  
Katsuhiko Arai
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Slope Failure ◽  
Numerical Procedure ◽  
Critical Value ◽  
Model Tests ◽  
Laboratory Model ◽  
Response Analysis ◽  
Seismic Slope Stability ◽  
Plastic Displacement

The results of laboratory model tests for simulating the slope failure due to vibration, including unreinforced slope and the slope reinforced by using geotextile, show that the slope failure occurs when a cumulative plastic displacement exceeds a certain critical value. To overcome the defects of conventional stability analysis, which evaluates the slope characteristics only by its strength parameters, a numerical procedure considering the stiffness and deformation of materials and geosynthetics is proposed to evaluate the seismic slope stability. In the proposed procedure, the failure of slope is defined when the cumulative plastic displacement calculated by a dynamic response analysis using actual seismic wave exceeds the critical value of displacement estimated by a static stability analysis considering seismic coefficient. The proposed procedure is applied to the laboratory model tests and an actual failure of slope in earthquake. The case study shows the possibility that the proposed procedure gives the realistic evaluation of seismic slope stability.

scholarly journals Experimental Study of Site-Specific Soil Water Content and Rainfall Inducing Shallow Landslides: Case of Gakenke District, Rwanda

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Martin Kuradusenge ◽  
Santhi Kumaran ◽  
Marco Zennaro ◽  
Albert Niyonzima
Keyword(s):  
Experimental Study ◽  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Early Warning ◽  
Slope Failure ◽  
Shallow Landslides ◽  
Specific Site

Shallow landslides are among the natural threats causing death and damage. They are mostly triggered by rainfall in mountainous areas where precipitation used to be abundant. The amount of rainfall inducing this natural threat differs from one site to another based on the geographical characteristics of that area. In addition to the rainfall depth, the determination of soil water content in a specific zone has a major contribution to the landslide prediction and early warning systems. Rwanda being a country with hilly terrains, some areas are susceptible to both rainfall and soil water content inducing landslides. But an analytical study of the physical threshold determination of both rainfall and soil water content inducing landslides is lacking. Therefore, this experimental study is conducted to determine the rainfall and soil water content threshold that can be fed in to the landslide early warning system (LEWS) for alert messages using the Internet of Things (IoT) technology. Various experiments have been conducted for the real-time monitoring of slope failure using the toolset composed of a rain gauge, soil moisture sensors, and a rainfall simulating tool. The results obtained show that the threshold for landslide occurrence does not solely correlate with the total rainfall amount (or intensity) or soil moisture, but also influenced by internal (geological, morphological) and environmental factors. Among the sampled sites, the sites covered by forest indicated no sign of slope failure, whereas sites with crops could slip. The experiments revealed that for a specific site, the minimum duration to induce slope failure was 8 hours, 41 minutes with the rainfall intensity of 8 mm/hour, and the soil moisture was above 90% for deeper sensors. These values are used as thresholds for LEWS for that specific site to improve predictions.

scholarly journals Laboratory and 3-D distinct element analysis of the failure mechanism of a slope under external surcharge

2015 ◽  
Vol 15 (1) ◽  
pp. 35-43 ◽  
Author(s):  
N. Li ◽  
Y. M. Cheng
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Slip Surface ◽  
Distinct Element ◽  
Failure Mechanisms ◽  
Laboratory Model ◽  
Element Analysis ◽  
Additional Information ◽  
Major Disaster ◽  
Failure Conditions

Abstract. Landslide is a major disaster resulting in considerable loss of human lives and property damages in hilly terrain in Hong Kong, China and many other countries. The factor of safety and the critical slip surface for slope stabilization are the main considerations for slope stability analysis in the past, while the detailed post-failure conditions of the slopes have not been considered in sufficient detail. There is however increasing interest in the consequences after the initiation of failure that includes the development and propagation of the failure surfaces, the amount of failed mass and runoff and the affected region. To assess the development of slope failure in more detail and to consider the potential danger of slopes after failure has initiated, the slope stability problem under external surcharge is analyzed by the distinct element method (DEM) and a laboratory model test in the present research. A more refined study about the development of failure, microcosmic failure mechanisms and the post-failure mechanisms of slopes will be carried out. The numerical modeling method and the various findings from the present work can provide an alternate method of analysis of slope failure, which can give additional information not available from the classical methods of analysis.

Slope Stability Assessment Based on Fuzzy Matter-Element Extension Model

2012 ◽  
Vol 170-173 ◽  
pp. 366-370
Author(s):  
Jin Feng Liu ◽  
Guo Qiang Ou ◽  
Yong You
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Stability Result ◽  
Field Investigation ◽  
Western China ◽  
Stability Assessment ◽  
Extension Model ◽  
Elevation Difference ◽  
Mitigation Design ◽  
Total Study Area

The slope stability assessment is performed to assess the safe and mitigation design of slopes and the equilibrium conditions. This paper selected Duke River located in Rangtang County, Sichuan Province, Western China as study area to delimit the areas liable to slope failure hazards. The fuzzy matter-element extension theory was used to analyze the slope stability of the study area. Six factors including slope, slope type, lithology, rainfall, elevation difference and land use were selected and classfied for assessing the slope stability. Result indicated that the unstable region was 1186 km2, which occupies 69.32% of the total study area. 16 slope failure hazards and 29 debris flow gullies sited through field investigation were used to test the assessing results. And the testing data indicated that the assessing result of the study area was reasonable.

scholarly journals Laboratory and 3-D-distinct element analysis of failure mechanism of slope under external surcharge

2014 ◽  
Vol 2 (9) ◽  
pp. 5937-5970 ◽  
Author(s):  
N. Li ◽  
Y. M. Cheng
Keyword(s):  
Slope Stability ◽  
Failure Mechanism ◽  
Slope Failure ◽  
Slip Surface ◽  
Distinct Element ◽  
Laboratory Model ◽  
Element Analysis ◽  
Additional Information ◽  
Major Disaster ◽  
Failure Conditions

Abstract. Landslide is a major disaster resulting in considerable loss of human lives and property damages in hilly terrain in Hong Kong, China and many other countries. The factor of safety and the critical slip surface for slope stabilization are the main considerations for slope stability analysis in the past, while the detailed post-failure conditions of the slopes have not been considered in sufficient details. There are however increasing interest on the consequences after the initiation of failure which includes the development and propagation of the failure surfaces, the amount of failed mass and runoff and the affected region. To assess the development of slope failure in more details and to consider the potential danger of slopes after failure has initiated, the slope stability problem under external surcharge is analyzed by the distinct element method (DEM) and laboratory model test in the present research. A more refined study about the development of failure, microcosmic failure mechanism and the post-failure mechanism of slope will be carried out. The numerical modeling method and the various findings from the present work can provide an alternate method of analysis of slope failure which can give additional information not available from the classical methods of analysis.

scholarly journals The Hydromechanical Interplay in the Simplified Three-Dimensional Limit Equilibrium Analyses of Unsaturated Slope Stability

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 73
Author(s):  
Panagiotis Sitarenios ◽  
Francesca Casini
Keyword(s):  
Analytical Solution ◽  
Slope Stability ◽  
Slope Failure ◽  
Failure Modes ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Three Dimensional ◽  
Stability Limit ◽  
Smooth Transition

This paper presents a three-dimensional slope stability limit equilibrium solution for translational planar failure modes. The proposed solution uses Bishop’s average skeleton stress combined with the Mohr–Coulomb failure criterion to describe soil strength evolution under unsaturated conditions while its formulation ensures a natural and smooth transition from the unsaturated to the saturated regime and vice versa. The proposed analytical solution is evaluated by comparing its predictions with the results of the Ruedlingen slope failure experiment. The comparison suggests that, despite its relative simplicity, the analytical solution can capture the experimentally observed behaviour well and highlights the importance of considering lateral resistance together with a realistic interplay between mechanical parameters (cohesion) and hydraulic (pore water pressure) conditions.

scholarly journals Solid Form and Phase Transformation Properties of Fexofenadine Hydrochloride during Wet Granulation Process

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 802
Author(s):  
Suye Li ◽  
Hengqian Wu ◽  
Yanna Zhao ◽  
Ruiyan Zhang ◽  
Zhengping Wang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Transformation ◽  
Water Content ◽  
Scale Up ◽  
Small Scale ◽  
Dissolution Behavior ◽  
Wet Granulation ◽  
Water Addition ◽  
Granulation Process ◽  
And Performance

The quality control of drug products during manufacturing processes is important, particularly the presence of different polymorphic forms in active pharmaceutical ingredients (APIs) during production, which could affect the performance of the formulated products. The objective of this study was to investigate the phase transformation of fexofenadine hydrochloride (FXD) and its influence on the quality and performance of the drug. Water addition was key controlling factor for the polymorphic conversion from Form I to Form II (hydrate) during the wet granulation process of FXD. Water-induced phase transformation of FXD was studied and quantified with XRD and thermal analysis. When FXD was mixed with water, it rapidly converted to Form II, while the conversion is retarded when FXD is formulated with excipients. In addition, the conversion was totally inhibited when the water content was <15% w/w. The relationship between phase transformation and water content was studied at the small scale, and it was also applicable for the scale-up during wet granulation. The effect of phase transition on the FXD tablet performance was investigated by evaluating granule characterization and dissolution behavior. It was shown that, during the transition, the dissolved FXD acted as a binder to improve the properties of granules, such as density and flowability. However, if the water was over added, it can lead to the incomplete release of the FXD during dissolution. In order to balance the quality attributes and the dissolution of granules, the phase transition of FXD and the water amount added should be controlled during wet granulation.

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