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.

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.

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.

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.

Response of Soil Suction to Heavy Rainfalls in a Tailings Dam

2011 ◽  
Vol 250-253 ◽  
pp. 1681-1685 ◽  
Author(s):  
Rui Chen ◽  
Ben Zhuo Zhang ◽  
Wei Dong Lei ◽  
Wen Bin Luo
Keyword(s):  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Shallow Landslide ◽  
Rainfall Infiltration ◽  
Tailings Dam ◽  
Wetting Front ◽  
Tailings Dams ◽  
The Impact ◽  
Heavy Rainfalls

Rainfall is a significant factor leading to failure of tailings dams. The impact of rainfall on the instability of dams is mainly reflected in the variation of negative pore-water pressure (i.e. matric suction) during rainfall infiltration. However, there is a lack of study on the effects of rainfall on suction in tailings dams. In this study, the response of suction to artificial heavy rainfalls in a tailings dam was investigated. The effects of rainfall intensity and surface vegetation conditions on the response of suction were studied. It is found that suctions at a certain depth in the tailing dam were kept constant until the wetting front reached this depth. Once suctions were altered, the values dropped rapidly. The magnitude of suction change generally decreased with depth. Rainfall infiltration mainly occurred above the depth of 40 to 80 cm when subjected to rainstorm and heavy rainstorms. Larger rainfall intensity leads to shorter response time and to larger depth affected by rainfall, implying that the tailings dam is more susceptible to shallow landslide failure under larger rainfall intensity. The existing vegetation increases infiltrability significantly and then produces an adverse effect on the stability of the tailings dam. On the other hand, it is observed that the presence of vegetation greatly prevented surface erodibility and then decreases the possibility of debris flow.

scholarly journals Analysis of Pore Water Pressure and Piping of Hydraulic Well

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 502
Author(s):  
Jinman Kim ◽  
Heuisoo Han ◽  
Yoonhwa Jin
Keyword(s):  
Numerical Analysis ◽  
Water Level ◽  
Pore Water ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Hydraulic Gradient ◽  
Water Levels ◽  
Seepage Velocity ◽  
Seepage Analysis

This paper shows the results of a field appliance study of the hydraulic well method to prevent embankment piping, which is proposed by the Japanese Matsuyama River National Highway Office. The large-scale embankment experiment and seepage analysis were conducted to examine the hydraulic well. The experimental procedure is focused on the pore water pressure. The water levels of the hydraulic well were compared with pore water pressure data, which were used to look over the seepage variations. Two different types of large-scale experiments were conducted according to the installation points of hydraulic wells. The seepage velocity results by the experiment were almost similar to those of the analyses. Further, the pore water pressure oriented from the water level variations in the hydraulic well showed similar patterns between the experiment and numerical analysis; however, deeper from the surface, the larger pore water pressure of the numerical analysis was calculated compared to the experimental values. In addition, the piping effect according to the water level and location of the hydraulic well was quantitatively examined for an embankment having a piping guide part. As a result of applying the hydraulic well to the point where piping occurred, the hydraulic well with a 1.0 m water level reduced the seepage velocity by up to 86%. This is because the difference in the water level between the riverside and the protected side is reduced, and it resulted in reducing the seepage pressure. As a result of the theoretical and numerical hydraulic gradient analysis according to the change in the water level of the hydraulic well, the hydraulic gradient decreased linearly according to the water level of the hydraulic well. From the results according to the location of the hydraulic well, installation of it at the point where piping occurred was found to be the most effective. A hydraulic well is a good device for preventing the piping of an embankment if it is installed at the piping point and the proper water level of the hydraulic well is applied.

scholarly journals Stability Improvement Method for Embankment Dam with Respect to Conduit Cracks

2022 ◽  
Vol 12 (2) ◽  
pp. 567
Author(s):  
Young-Hak Lee ◽  
Jung-Hyun Ryu ◽  
Joon Heo ◽  
Jae-Woong Shim ◽  
Dal-Won Lee
Keyword(s):  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Dimensional ◽  
Internal Erosion ◽  
Scale Model ◽  
Seepage Analysis ◽  
Large Scale Model ◽  
Proposed Model ◽  
Improvement Method

In recent years, as the number of reservoir embankments constructed has increased, embankment failures due to cracks in aging conduits have also increased. In this study, a crack in a conduit was modeled based on the current conduit design model, and the risk of internal erosion was analyzed using a large-scale model test and three-dimensional deformation–seepage analysis. The results show that when cracks existed in the conduit, soil erosion and cavitation occurred near the crack area, which made the conduit extremely vulnerable to internal erosion. Herein, a model is proposed that can reduce internal erosion by applying a layer of sand and geotextiles on the upper part of the conduit located close to the downstream slope. In the proposed model, only partial erosion occurred inside the conduit, and no cavitation appeared near the crack in the conduit. The results suggest that internal erosion can be suppressed when the water pressure acting intensively on the crack in the conduit is dispersed by the drainage layer. To validate these results, the pore water pressure, seepage line, and hydraulic gradient were investigated to confirm the erosion phenomenon and reinforcement effect.

scholarly journals Numerical Analysis to Assess the Vertical Drainage Within Flexible Pavement.

2018 ◽  
Vol 7 (4.20) ◽  
pp. 95
Author(s):  
Aqeel Al-Adili ◽  
Rasha H. Abdul-Amir ◽  
Osamah Hassan Chfat
Keyword(s):  
Cross Section ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Flux ◽  
Flexible Pavement ◽  
Laboratory Model ◽  
Typical Structure ◽  
Rainy Period ◽  
Vertical Drainage

In this research the work methodology include the software program SEEP/W routine of the GEOSLOPE 2012; which was used to simulate and analyze the vertical drainage of the pavement cross section using steady-state and transient analysis. A laboratory model consisting of typical structure layers of flexible pavement was considered in this research with a 2% slope with the influence of three different rain intensities (30mm/min, 60mm/min and 90mm/min); in which each one has a duration differs from the other. The results indicated that the value of the pore-water pressure in the surface layer resulting from 90 mm/min rainfall intensity is 83.65% greater than the pressure generated by the 60mm/min intensity of rain and 91.076% greater than the pressure produced from 30mm/min intensity. The average of accumulation water produced by the 30mm/min rainfall intensity in the pavement structure is 44.73 % greater than the average of accumulation of water from the 60mm/min intensity and 77.85% higher than the 90mm/min intensity of rain. The water flux through the pavement cross section during the rainy period of 30 mm/min was 8.42% higher than the water flux of 60 mm/min and 49.82% of the water flux of 90 mm/min intensity of rain.  

scholarly journals Slope Stability Analysis of Unsaturated Soil Slopes Based on the Site-Specific Characteristics: A Case Study of Hwangryeong Mountain, Busan, Korea

2020 ◽  
Vol 12 (7) ◽  
pp. 2839
Author(s):  
Sinhang Kang ◽  
Seung-Rae Lee ◽  
Sung-Eun Cho
Keyword(s):  
Relative Permeability ◽  
Rainy Season ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Air Flow ◽  
Influential Factors ◽  
Rainfall Infiltration ◽  
Site Specific ◽  
Hourly Rainfall

Shallow slope failures occur almost every year during the rainy season. Continuous observation of the meteorological parameters and hydrological characteristics is required to more clearly understand the triggering mechanisms of shallow slope failure. In addition, influential factors, such as type of relative permeability models, air flow, and variation of hydraulic conductivity associated with stress–strain behavior of soil, have significant effects on the actual mechanism of rainfall infiltration. Real-time data including hourly rainfall and pore water pressure in response to rainfall was recorded by devices; then, the change in pore pressure from the devices was compared to the results from the infiltration analysis with applications of three relative permeability models, air flow, and the coupled hydro-mechanical analysis to examine an appropriate site-specific approach to a rainfall infiltration analysis. The infiltration and stability analyses based on the site-specific hydrologic characteristics were utilized to create maps of safety factors that depend on the cumulative rainfall. In regions vulnerable to landslides, rainfall forecast information and safety factor maps built by applying various rainfall scenarios can be useful in preparing countermeasures against disasters during the rainy season.

Unsaturated Seepage and Fluid-Solid Coupling Analysis of Rainfall Infiltration of Slope

2011 ◽  
Vol 255-260 ◽  
pp. 3488-3492
Author(s):  
Bao Lin Xiong ◽  
Jing Song Tang ◽  
Chun Jiao Lu
Keyword(s):  
Pore Water ◽  
Unsaturated Flow ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Rainfall Infiltration ◽  
Medium Permeability ◽  
Stability Of Slope ◽  
Transient Seepage ◽  
The Stability ◽  
Unsaturated Seepage

Rainfall is one of the main factors that influence the stability of slope. Rainfall infiltration will cause soil saturation changing and further influence pore water pressure and medium permeability coefficient. Based on porous media saturation-unsaturated flow theory, the slope transient seepage field is simulated under the conditions of rainfall infiltration. It is shown that change of pore water pressure in slope soil lag behind relative changes in rainfall conditions. As the rainfall infiltrate, unsaturated zone in top half of slope become diminution, the soil suction and shear strength reduce, so stabilization of soil slope is reduced.

Study on Slope Instability Disciplinarian on the Condition of Rainfall

2013 ◽  
Vol 353-356 ◽  
pp. 654-658
Author(s):  
Nan Tong Zhang ◽  
Xiao Chun Zhang ◽  
Hua Rong Wang ◽  
Chen Yan
Keyword(s):  
Slope Stability ◽  
Tensile Stress ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Road Construction ◽  
Slope Instability ◽  
Slope Surface ◽  
Large Area ◽  
Break Zone

Slope stability is one of the problems of road construction which should be faced with and solve. Rainfall can reduce the shear strength of slope soil and raise the underground water level which can lead to increase slope soil pore water pressure. The influence of rainfall infiltration on slop is mainly to change the slope seepage field, increase dynamic and hydrostatic water load on the slope soil and decrease of soil shear parameters. More abundant rainfall of typhoon area could make the road slope stability more fragile. Based on Matoushan Mountain along 104 state roads in Taizhou city, Zhejiang province, slope instability disciplinarian on the condition of rainfall is studied using the method of numerical simulation in this paper. As the results, when the rainfall intensity was 0.006 m/h and continuous rain was in 24 hours, the slope surface compressive stress tends to zero which began to appear tensile stress area on the condition of self-weight. And when the rainfall intensity was 0.01 m/h and continuous rain was in 24 hours, the large area of the slope surface was tensile stress area which means to appear break zone in slope surface and likely to landslide at the same time.

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