scholarly journals ANALYSIS OF UNSATURATED SOIL PARAMETERS AS SLOPE STABILITY MITIGATION

2017 ◽  
Vol 79 (7-2) ◽  
Author(s):  
Heriansyah Putra ◽  
Ahmad Rifa`i ◽  
Joko Sujono ◽  
Alfira Silarukmi
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Safety Factor ◽  
Unsaturated Soil ◽  
Critical Condition ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Parameters ◽  
Shear Strength Parameters ◽  
Strength Parameters

The pore water pressure is the essential factor and plays a key role in the unsaturated soil parameters. Experimental works and numerical analysis were conducted to determine the critical condition of the slope stability due to the evolution of shear strength parameters. The effect of infiltration on the pore water pressure was evaluated. The filter paper method was conducted to obtain the matric suction in various degrees of saturation. The mechanical properties of the undisturbed samples were examined through triaxial and permeability test, respectively. WRPLOT ViewTM was adopted to assess the intensity and duration of the actual rainfall. The applicability of the psycho-empirical method in SOILVISION Database to fit Soil Water Characteristic Curve (SWCC) was studied. GEO-SLOPE was used to assess the evolution of the pore water pressure and its effect on the safety factor of the slope. The evolution of pore water pressure induced the infiltration influenced the shear strength parameters and reduced the safety factor. The reduction 20% of cohesion was obtained and hence, the safety factor decrease to 1.0. The infiltration at the beginning of the wet season is the most critical condition that increases the soil moisture significantly.

scholarly journals Unsaturated seepage and stability of double-layer slope under rainfall infiltration

2021 ◽  
Vol 248 ◽  
pp. 03024
Author(s):  
Yuan Zhang ◽  
Haifeng Lu
Keyword(s):  
Slope Stability ◽  
Pore Water ◽  
Safety Factor ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Parameters ◽  
Lag Period ◽  
Rainfall Patterns ◽  
Continuous Rainfall ◽  
Slope Safety

Taking a homogeneous double-layer soil slope as an example, the SEEP/W module and SLOPE/W module in the finite element analysis software GeoStudio were used in this paper. Then, the changes of pore water pressure and stability under different rainfall patterns and soil parameters were studied. Finally, the variation curves of pore water pressure and slope safety factor with rainfall time were obtained. The results show that: Soil parameters a and m are directly proportional to the slope safety factor, while n is inversely proportional to the slope safety factor. Under the condition of continuous rainfall, the decreasing rate of slope safety factor is directly proportional to the rainfall intensity.Under different rainfall patterns, the continuous rainfall in the advanced and normal rainfall patterns will cause the slope stability to decline and then gradually recover, while delayed and averaged rainfall patterns rainfall will cause the slope stability to decline continuously.In addition, there is a lag period in the change of slope safety factor, and the whole lag period lasts about 6 hours. During the lag period, the pore water pressure inside the soil began to decrease, while the slope safety factor continued to decrease. The safety factor starts to recover after the lag period ends.

scholarly journals Model testing on rainfall-induced landslide of loose soil in Wenchuan earthquake region

2012 ◽  
Vol 12 (3) ◽  
pp. 527-533 ◽  
Author(s):  
H. Fang ◽  
P. Cui ◽  
L. Z. Pei ◽  
X. J. Zhou
Keyword(s):  
Shear Strength ◽  
Wenchuan Earthquake ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Experimental Investigations ◽  
Soil Parameters ◽  
Artificial Rainfall ◽  
Loose Soil ◽  
Porosity Ratio

Abstract. This study investigates the formation process of rainfall-induced landslide for slopes composed of loose soil in the Wenchuan earthquake region. Experimental investigations have been performed on the landslide's formation and the variation of the controlling soil parameters under various artificial rainfall conditions. The landslide triggering mechanisms can be described in the following way. Firstly, the large porosity of the loose soil facilitated the infiltration of water, which increased the pore water pressure and reduced the shear strength of the soil significantly. In addition, the rainfalls probably caused the concentration of finer particles at a certain depth of the valley slopes. This concentration within the soil increased the pore water pressure significantly, and consequently reduced both the porosity ratio and permeability. Therefore, when the pore water pressure reached a critical state, the effective shear strength of the soil diminished, inducing the landslide's formation.

scholarly journals The meaning of effective soil parameters for determining of the bearing capacity of cohesive soils

2014 ◽  
Vol 13 (2) ◽  
pp. 057-064
Author(s):  
Krzysztof Wilk
Keyword(s):  
Bearing Capacity ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Parameters ◽  
Physical Parameters ◽  
Cohesive Soils ◽  
Strength Parameters ◽  
Triaxial Apparatus ◽  
Soil Skeleton

The paper presents the analysis of the bearing capacity of cohesive soils, which was calculated based on the PN-EN-1997-1 methodology. This computations take into account the effect of pore water pressure on the soil strength parameters. The parameters for calculating the strength of the soil can be determined by direct tests (triaxial apparatus) or by indirect methods. Used in the previous norm PN-81/B-03020 correlations of physical parameters and strength parameters relate to the total stress. They do not include, what part of the stress is carried by an increase the pore water pressure, and what part acts on the soil skeleton. The problem of dispersion efficiency of excessive the pore water pressure during load relates in particular the soils with the fine particle sizes - cohesive soils. There is no defined dependencies, which can be used in indirect determining the bearing capacity of cohesive substrate according to PN-EN-1997-1.

scholarly journals The 22 February 2018 landslide mechanism in Pasir Panjang Village, Brebes Regency, Central Java, Indonesia

2019 ◽  
Vol 4 (2) ◽  
pp. 92
Author(s):  
Wahyu Wilopo ◽  
Adam Raka Ekasara ◽  
Hendy Setiawan ◽  
Dwikorita Karnawati
Keyword(s):  
Shear Strength ◽  
Slip Surface ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Back Analysis ◽  
Silty Sand ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Central Java

On 22 February 2018 landslide occurred in Pasir Panjang Village, Salem District, Brebes Regency of Central Java Province, Indonesia. About 8 people were died, 4 people were injured and several infrastructures were damaged due to this landslide. This research is carried out to understand geological-geotechnical condition and to study the initiation mechanism of the landslide. Field investigation and UAV mapping are carried out to detect slip surface and define slope geometry. The rainfall-induced pore-water pressure is estimated by using the Slope Infiltration Distributed Equilibrium (SLIDE) model. Then, limit equilibrium method is used to estimate the safety factor of the slope, while the shear strength parameters are determined by applying back analysis approach that compared with data from laboratory tests. The results show that landslide occurred in permeable layer of silty sand overlaid above impermeable andesitic breccia. Results from back analysis indicate that the shear strength parameters and rainfall intensity are strongly influence the stability of slope against landslide.

scholarly journals Effect of water infiltration on the mechanical behaviour of unsaturated soil

2019 ◽  
Vol 92 ◽  
pp. 07002
Author(s):  
Ali Murtaza Rasool ◽  
Jiro Kuwano
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Unsaturated Soil ◽  
Mechanical Behaviour ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Infiltration ◽  
Confining Stress ◽  
Effect Of Water ◽  
The Stability

Natural slopes and embankments are generally unsaturated in nature with negative pore water pressure adding to the shear strength and hence the stability of the slopes. During the event of rainfall, pore water pressure becomes less negative or even positive as a result the shear strength of soil decreases and failure occur. Therefore, the strength and deformation characteristics for unsaturated soil become important when analysing the stability of these types of slopes. In this study, a triaxial test apparatus was used to study the effect of water infiltration on the mechanical behaviour of unsaturated soil. The test results show that water infiltration decreased with increase in net confining stress and the stress paths were independent of the matric suction, the net confining stress and the shearing conditions for the present experimental study.

Conjectures, Hypotheses, and Theories of Drumlin Formation (In memory of Stanislaw Baranowski)

1981 ◽  
Vol 27 (97) ◽  
pp. 503-505 ◽  
Author(s):  
Ian J. Smalley
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Stress Level ◽  
Critical Stress ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Glacial Till ◽  
Forming Process ◽  
Stress Levels

AbstractRecent investigations have shown that various factors may affect the shear strength of glacial till and that these factors may be involved in the drumlin-forming process. The presence of frozen till in the deforming zone, variation in pore-water pressure in the till, and the occurrence of random patches of dense stony-till texture have been considered. The occurrence of dense stony till may relate to the dilatancy hypothesis and can be considered a likely drumlin-forming factor within the region of critical stress levels. The up-glacier stress level now appears to be the more important, and to provide a sharper division between drumlin-forming and non-drumlin-forming conditions.

The Research of Pore Water Pressure Effect on the Slope Safety Factor Based on Flac

2012 ◽  
Vol 166-169 ◽  
pp. 1433-1436 ◽  
Author(s):  
Hai Bo Liu ◽  
Li Hua Zhang ◽  
Da Hao Lin
Keyword(s):  
Pore Water ◽  
Safety Factor ◽  
Pressure Effect ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Slope Safety

On the basis of the Australian Computer Society(ACADS)`s typical questions1(a),first, regardless of the slope in the case of pore water pressure, used FLAC procedure calculate the safety factor, the result was very close to the reference answer given by ACADS, we can see the accuracy of FLAC. Then, applied to the slope of different pore water pressure, obtained safety factor under corresponding conditions, then, we found that the pore water pressure had effect on the slope safety factor, but the influence are not same, when the pore water pressure less than a certain value, the influence are very small, but, when the pore water pressure exceeded this value, the influence became very large.

Security Control Method of Loading for Surcharge Preloading Based on the Stress Path

2011 ◽  
Vol 368-373 ◽  
pp. 2795-2803
Author(s):  
Heng Hu ◽  
Yan Li ◽  
Zhi Liang Dong ◽  
Yan Luo ◽  
Gong Xin Zhang
Keyword(s):  
Pore Water ◽  
Safety Factor ◽  
Control Method ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Stress Path ◽  
Excess Pore Water Pressure ◽  
Surcharge Preloading ◽  
Security Control ◽  
Excess Pore

All the time, security control method of loading is an important research part in the surcharge preloading, which is directly related to safety of the construction process. Starting from the stress path, discussing the variation of excess pore water pressure and relationship between stress path and security, and bringing forward the control method with a safety factor Fs based on the stress path. By measuring the change of excess pore water pressure, the control method with a safety factor Fs can reflect quantitatively the security status of soil and achieve the purpose of the process control, finally the security control method including the safety factor of loading and speed control is put forward to monitor construction safety. The safety factor of loading Fs is verified and back analyzed with the finite-element software, getting the correction factor from 0.90 to 1.20.

Sign in / Sign up

Export Citation Format

Share Document