The Analysis of Seepage Characteristics and Stability of Carbonaceous Mudstone Embankment Slope in Rainfall Condition

2012 ◽  
Vol 446-449 ◽  
pp. 1864-1868 ◽  
Author(s):  
Ling Zeng ◽  
Hong Yuan Fu ◽  
Tao Li ◽  
Yan Qi Qin
Keyword(s):  
Moisture Content ◽  
Pore Water ◽  
Slope Failure ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Intensity Change ◽  
Safety Coefficient ◽  
Embankment Slope ◽  
Volumetric Moisture Content

Based on the actual rainfall data and saturated-unsaturated seepage theory, the change of pore water pressure and volumetric moisture content of carbonaceous mudstone embankment slope were studied under designed rainfall intensity. At the same time, the effect of rainfall intensity change on the slope failure mode and safety coefficient was analyzed. The results of the study show that: Continuous rainfall will make the surface layer negative pore water pressure of carbonaceous mudstone embankment slope loss, and in transient saturation zone the volumetric moisture content reaches the saturated moisture content. Safety coefficient of carbonaceous mudstone embankment slope gradually decreases with the rainfall continuing, potential sliding surface also have the tendency of extending into the embankment.

Analysis of Seepage Field and Stability of Clinosol Slope under Rainfall Infiltration

2013 ◽  
Vol 353-356 ◽  
pp. 307-311 ◽  
Author(s):  
Xi Yi Yang ◽  
Fang Guo
Keyword(s):  
Moisture Content ◽  
Pore Water ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Rainfall Infiltration ◽  
Seepage Field ◽  
Volumetric Moisture Content ◽  
Initial Stage

In order to research on slope seepage field and slop stability under rainfall infiltration, this paper combines finite element with limit equilibrium theory to study. The results show that under rainfall, pore water pressure of the slope crest and slope toe in slope wash is greatly influenced by rainfall; Change in the volume moisture content is more sensitive than pore water pressure, volumetric moisture content of each location is increasing quickly at the initial stage of rain, volumetric moisture content in the lower locations is the first to reach saturated due to the continued supply and gravity of the rain; The slope stability reduces with rainfall infiltration, the greater the rainfall intensity, the more obvious decline the slope safety factor.

Research of Slope Stability Analysis Considering Rainfall Infiltration

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.

Type of Slope Failure Identified from Pore Water Pressure and Moisture Content Measurements

2015 ◽  
Vol 744-746 ◽  
pp. 690-694
Author(s):  
Muhammad Rehan Hakro ◽  
Indra Sati Hamonangan Harahap
Keyword(s):  
Moisture Content ◽  
Pore Pressure ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Failure Process ◽  
Small Scale ◽  
Content Increase ◽  
Sudden Increase ◽  
Model Slope

Rainfall-induced landslides occur in many parts of the world and causing a lot of the damages. For effective prediction of rainfall-induced landslides the comprehensive understanding of the failure process is necessary. Under different soil and hydrological conditions experiments were conducted to investigate and clarify the mechanism of slope failure. The failure in model slope was induced by sprinkling the rainfall on slope composed of sandy soil in small flume. Series of tests were conducted in small scale flume to better understand the failure process in sandy slopes. The moisture content was measured with advanced Imko TDR (Time Domain Reflectrometry) moisture sensors in addition to measurements of pore pressure with piezometers. The moisture content increase rapidly to reach the maximum possible water content in case of higher intensity of rainfall, and higher intensity of the rainfall causes higher erosion as compared to smaller intensity of the rainfall. The controlling factor for rainfall-induced flowslides was density of the slope, rather than intensity of the rainfall and during the flowslide the sudden increase in pore pressure was observed. Higher pore pressure was observed at the toe of the slope as compared to upper part of the slope.

scholarly journals Seepage Analysis on the Surface Layer of Multistage Filled Slope with Rainfall Infiltration

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Bingxiang Yuan ◽  
Zengrui Cai ◽  
Mengmeng Lu ◽  
Jianbing Lv ◽  
Zhilei Su ◽  
...  
Keyword(s):  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Rainfall Infiltration ◽  
Feature Points ◽  
Saturation State ◽  
Seepage Analysis ◽  
Safety Coefficient ◽  
Infiltration Model ◽  
Saturation Region

Based on the theory of rainfall infiltration, the surface infiltration model of multilevel filled slope was established by using the SEEP/W module of GeoStudio. The changes of the volumetric water content (VWC) and pore water pressure (PWP) in the surface of the slope during the rainfall infiltration were analyzed, and the influence of the change of the rainfall conditions on the VWC and PWP was considered. The analysis showed that VWC and PWP increased when the rain fell, and the growth rate of the higher feature point was higher. The affected area was concentrated on the upper part of the surface about 0.75 m. With the increasing of rainfall intensity, the slope surface getting to transient saturation state was quick, and the time of the PWP increasing to 0 among the feature points of same elevation was shortened. Meanwhile, the PWP presented a positive value, and as the infiltration depth increased, the transient saturation region expanded. The safety coefficient of the multistage filled slope was continuously reduced; after the stop of rainfall, the VWC and the PWP decreased, and the decline rate of the higher feature points was higher. In addition, the PWP of the lower part increased, and the safety factor of the slope presented a trend of rebound.

Numerical Analysis of Characteristics of Moisture Migration in Soil Slope under Rainfall

2014 ◽  
Vol 501-504 ◽  
pp. 1927-1931
Author(s):  
Guang Ju Wen ◽  
Wen Jie Deng ◽  
Feng Wen
Keyword(s):  
Pore Water ◽  
Permeability Coefficient ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Soil Mechanics ◽  
Water Pressure ◽  
Point Of View ◽  
Moisture Migration ◽  
Unsaturated Soil Mechanics ◽  
Nonlinear Distribution

Based on the characteristics of slope failure induced by rainfall, from the point of view of moisture migration and combining unsaturated soil mechanics, the characteristics of moisture migration in slope under different rainfall intensities were analyzed by finite element method. The results reveal that under rainfall, the pore water pressure in slope is in layered distribution, and at the bottom of slope, the pore water pressure is the highest, the top is lower and the middle is the lowest. The volumetric water content is in nonlinear distribution and the degree of nonlinear in unsaturated area is higher than that of the saturated area. The permeability coefficient of soil rises with the increase of rainfall intensity, and when the soil is saturated, its permeability coefficient is saturate permeability coefficient.

scholarly journals Analysis of shallow failures triggered by the 14-16 November 2002 event in the Albaredo valley, Valtellina (Northern Italy)

2005 ◽  
Vol 2 ◽  
pp. 305-308 ◽  
Author(s):  
S. Dapporto ◽  
P. Aleotti ◽  
N. Casagli ◽  
G. Polloni
Keyword(s):  
Pore Water ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Coupled Analysis ◽  
Element Analysis ◽  
Seepage Analysis ◽  
The North ◽  
Pressure Distributions

Abstract. On 14-16 November 2002 the North Italy was affected by an intense rainfall event: in the Albaredo valley (Valtellina) more than 200 mm of rain fell triggering about 50 shallow landslides, mainly soil slips and soil slip-debris flows. Landslides occurred above the critical rainfall thresholds computed by Cancelli and Nova (1985) and Ceriani et al. (1994) for the Italian Central Alps: in fact the cumulative precipitation at the soil slips initiation time was 230 mm (in two days) with a peak intensity of 15 mm/h. A coupled analysis of seepage and instability mechanisms is performed in order to evaluate the potential for slope failure during the event. Changes in positive and negative pore water pressures during the event are modelled by a finite element analysis of water flow in transient conditions, using as boundary condition for the nodes along the slope surface the recorded rainfall rate. The slope stability analysis is conducted applying the limit equilibrium method, using pore water pressure distributions obtained in the different time steps by the seepage analysis as input data for the calculation of the factor of safety.

scholarly journals Laboratory Experiment and Numerical Analysis on the Precursory Hydraulic Process of Rainfall-Induced Slope Failure

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Joon-Young Park ◽  
Young-Suk Song
Keyword(s):  
Numerical Modeling ◽  
Laboratory Test ◽  
Water Content ◽  
Pore Water ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Volumetric Water Content ◽  
Wetting Front ◽  
Artificial Rainfall

A combined analysis involving a laboratory test and numerical modeling was performed to investigate the hydraulic processes leading to slope failure during rainfall. Through a laboratory landslide test in which artificial rainfall was applied to a homogeneous sandy slope, the timing and configurations of multiple slides were identified. In addition, volumetric water content was measured in real time through the use of monitoring sensors. The measured volumetric water content data were then used to validate the relevance of the numerical modeling results. The validated numerical modeling of the laboratory-scale slope failures provided insight into the hydraulic conditions that trigger landslides. According to the numerical modeling results, the miniaturized slope in the laboratory test was saturated in a manner so that the wetting front initially progresses downward and then the accumulated rainwater at the toe of the slope creates a water table that advances toward the crest. Furthermore, each of the five sequential failures that occurred during this experiment created slip surfaces where the pore-water pressure had achieved full saturation and an excessive pore-water pressure state. The findings of this study are expected to help understand the hydraulic prerequisites of landslide phenomena.

Slope Monitoring System at a Slope Behind an Important Cultural Asset

2011 ◽  
Vol 6 (1) ◽  
pp. 70-79 ◽  
Author(s):  
Kazunari Sako ◽  
◽  
Ryoichi Fukagawa ◽  
Tomoaki Satomi ◽  
◽  
...  
Keyword(s):  
Field Measurement ◽  
Slope Failure ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Numerical Models ◽  
Water Pressure ◽  
Measurement Data ◽  
Warning System ◽  
Set Up ◽  
Relationship Of

Rainfall-induced slope failure has been responsible for great death and destruction in Japan. This is thus a primary consideration in preserving Japan’s many cultural important temples, palaces, and similar structures, especially in the ancient capital of Kyoto, where many important cultural assets are located on hillsides and near mountains. Our objective is to construct a slope-disaster warning system using real-time field measurement data, in-situ and laboratory testing, and numerical models. We set up field monitoring on a slope behind an important cultural asset in July 2004 to measure pore-water pressure, temperature, and rainfall intensity [1]. We firstly introduce our slope-disaster warning concept and field measurement results for the slope behind the important cultural asset in Kyoto. And then we discuss the relationship of rainfall intensity, seepage behavior, and slope failure based on monitoring data and model test results using a soil box apparatus.

scholarly journals Characteristics of landslides in unwelded pyroclastic flow deposits, southern Kyushu, Japan

2015 ◽  
Vol 3 (10) ◽  
pp. 6351-6378 ◽  
Author(s):  
M. Yamao ◽  
R. C. Sidle ◽  
T. Gomi ◽  
F. Imaizumi
Keyword(s):  
Pyroclastic Flow ◽  
Slope Failure ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Antecedent Rainfall ◽  
Rainfall Characteristics ◽  
Antecedent Conditions ◽  
Duration Threshold ◽  
Different Types

Abstract. We investigated 184 landslides that occurred in unwelded pyroclastic flow deposits (Shirasu) on southern Kyushu Island, Japan, that included detailed data on the rainfall characteristics and the timing of slope failure. Localized rainfall intensity, antecedent rainfall, and topography affected the hydrologic processes that triggered landslides. Antecedent rainfall (adjusted for evapotranspiration losses) for large (> 200 mm) storms that triggered landslides was much lower than for smaller (≤ 200 mm) storms. Mean storm intensity and antecedent 7 day rainfall (API7) thresholds of > 5 mm h-1 and ≤ 30 mm (or API30 ≤ 60 mm), respectively, were useful to identify landslides triggered by rapid pore water pressure response, especially for shorter (< 20 h) duration events. During smaller storms with lower intensity, landslides are likely affected by a combined increase in soil weight and loss of suction when API30 ≥ 150 mm; simulations indicated that these weight and suction changes due to rainfall accumulation decreased factor of safety in steep Shirasu slopes, but did not necessarily trigger the landslides. All but two of the 21 landslides that plotted below a general rainfall intensity-duration threshold for landslide initiation had API30 values > 235 mm, indicating that they were highly influenced by the combined effects of the accumulated weight of rainfall and loss of suction. Our findings show that both event rainfall characteristics and antecedent conditions affect the hydrogeomorphic processes that trigger different types of landslides in Shirasu. This knowledge and the thresholds we have identified are useful for predicting the occurrence of different types of landslides in Shirasu deposits and improving sediment disaster prevention practices, including real-time warning systems.

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