scholarly journals An Investigation on performance of the cut off wall and numerical analysis of seepage and pore water pressure of Eyvashan earth dam

2021 ◽  
Author(s):  
Behrang Beiranvand ◽  
Mehdi Komasi
Keyword(s):  
Numerical Analysis ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Earth Dam ◽  
Coefficient Of Determination ◽  
Correct Operation ◽  
Seepage Rate ◽  
Reservoir Conditions ◽  
Good Agreement

AbstractOne of the most important issues in earth dams is the control rate of seepage from the foundation and dam bodies. Due to the site of the dams, to increase the creep length and reduce the seepage, there are several methods for sealing the reservoir of dams that construction of the cut-off wall under the clay core of the dams is one of the most effective methods. In this study, the seepage rate and pore water pressure of the Eyvashan earth dam, comparison of instrument results with the results of numerical analysis and, finally, the performance of the cut-off wall are investigated. According to the results of instrumental and numerical analysis, the maximum seepage rate in full reservoir conditions is equal to 831,604 m3/year. To fit the data of instrumentation and numerical analysis, multivariate regression was used and the coefficient of determination was used which R2 = 0.9892 and R2 = 0.9834, respectively, were obtained for seepage and pore water pressure. Very good agreement between the results of the observed data and the predicted data indicates the proper behavior of the dam in terms of pore water pressure. Also, due to the results of numerical simulation and instrumentation, the pore water pressure in the downstream part of the cut-off wall is suddenly dropped, which indicates the correct operation of the cut-off wall.

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 Elastic-Plastic Numerical Analysis of Tunnel Stability Based on the Closest Point Projection Method Considering the Effect of Water Pressure

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Zhan-ping Song ◽  
Ten-tian Yang ◽  
An-nan Jiang
Keyword(s):  
Rock Mass ◽  
Numerical Analysis ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Surrounding Rock ◽  
Tunnel Stability ◽  
Elastic Plastic ◽  
Closest Point Projection ◽  
Point Projection

To study the tunnel stability at various static water pressures and determine the mechanical properties and deformation behavior of surrounding rock, a modified effective stress formula was introduced into a numerical integration algorithm of elastic-plastic constitutive equation, that is, closest point projection method (CPPM). Taking the effects of water pressure and seepage into account, a CPPM-based formula was derived and a CPPM algorithm based on Drucker-Prager yield criterion considering the effect of pore water pressure was provided. On this basis, a CPPM-based elastic-plastic numerical analysis program considering pore water pressure was developed, which can be applied in the engineering of tunnels and other underground structures. The algorithm can accurately take the effects of groundwater on stability of surrounding rock mass into account and it can show the more pronounced effect of pore water pressure on stress, deformation, and the plastic zone in a tunnel. The stability of water flooding in Fusong tunnel was systematically analyzed using the developed program. The analysis results showed that the existence of groundwater seepage under tunnel construction will give rise to stress redistribution in the surrounding rock mass. Pore water pressure has a significant effect on the surrounding rock mass.

Representativeness of measurements in the interpretation of earth dam behaviour

2006 ◽  
Vol 43 (1) ◽  
pp. 87-99 ◽  
Author(s):  
Luca Pagano ◽  
Stefania Sica ◽  
Augusto Desideri
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Earth Dam ◽  
Measured Quantity ◽  
Pressure Measurements ◽  
Earth Dams ◽  
Pressure Monitoring ◽  
Spatial Continuity ◽  
Numerical Examples

The representativeness of measurements monitored in earth dams is analysed to investigate how a given measured quantity can be used to interpret the dam's mechanical behaviour. Representativeness is evaluated on the basis of spatial continuity of the measured quantity and the sensitivity of that quantity to natural mechanical nonhomogeneity. The discussion is supported by results from case studies and numerical examples. The study is mainly focused on pore-water pressure measurements. Spatial continuity of pore-water pressure is analysed with consideration of both saturation and drainage conditions. The paper discusses how pore-water pressure representativeness can vary over the lifetime of the dam.Key words: earth dam, pore-water pressure, monitoring.

Numerical Analysis on the Excess Pore Water Pressure of Pipe-Pile with Hole during the Static-Sinking Pile

2015 ◽  
Vol 744-746 ◽  
pp. 540-546
Author(s):  
Ke Lin Chen ◽  
Jin Bo Lei ◽  
Zhi Liu
Keyword(s):  
Numerical Analysis ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Effective Radius ◽  
Excess Pore Water Pressure ◽  
Pipe Pile ◽  
Time Space ◽  
Theory Research ◽  
Excess Pore

The time-space change rules of the environmental effects of the analysis of excess pore water pressure dissipation have also been studied during the static sinking-pile of the pipe-pile with hole. The results show: The excess pore water pressure will be dissipated with the time extending during the static sinking-pile of the 3 kinds of pipe-pole with hole. On the condition of the same effective radius, the depth of the observation dot is bigger, the excess pore water pressure will be bigger. On the contrast to the pipe-pole without hole, to some extent, the pipe-pole with hole can reduce the maximum of excess pore water pressure, and expedite the excess pore water pressure dissipation. This results can be provided the credible base for the theory research on the pipe-pole with hole and its application.

On the response of a poro-elastic bed to water waves

1978 ◽  
Vol 87 (1) ◽  
pp. 193-206 ◽  
Author(s):  
Tokuo Yamamoto ◽  
H. L. Koning ◽  
Hans Sellmeijer ◽  
Ep Van Hijum
Keyword(s):  
Porous Medium ◽  
Pore Water ◽  
Water Waves ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Dimensional ◽  
Fine Sand ◽  
Present Solution ◽  
Theoretical Results ◽  
Good Agreement

The problem of the response of a porous elastic bed to water waves is treated analytically on the basis of the three-dimensional consolidation theory of Biot (1941). Exact solutions for the pore-water pressure and the displacements of the porous medium are obtained in closed form for the case of waves propagating over the poro-elastic bed. The theoretical results indicate that the bed response to waves is strongly dependent on the permeabilitykand the stiffness ratioG/K’, whereGis the shear modulus of the porous medium andK’is the apparent bulk modulus of elasticity of the pore fluid. The earlier solutions for pore-water pressure by various authors are given as the limiting cases of the present solution. For the limitsG/K′→ 0 ork→ ∞, the present solution for pressure approaches the solution of the Laplace equation by Putnam (1949). For the limitG/K′→ ∞, the present solution approaches the solution of the heat conduction equation by Nakamuraet al.(1973) and Moshagen & Tørum (1975).The theoretical results are compared with wave tank experimental data on pore-water pressure in coarse and fine sand beds which contain small amounts of air. Good agreement between theory and experiment is obtained.

Determining Range of Saturated Ground around Leakage Pipeline Using Unsteady Seepage Numerical Analysis

2012 ◽  
Vol 204-208 ◽  
pp. 609-613
Author(s):  
Xing Gao Li ◽  
Chao Jie Duan
Keyword(s):  
Numerical Analysis ◽  
Hydraulic Conductivity ◽  
Water Content ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Injection Well ◽  
Exponential Relationship ◽  
Seepage Analysis ◽  
Conductivity Function

It is of great significance to estimate the range of saturated ground around leakage pipelines when tunneling near the pipelines. The range of saturated ground can be determined from the distributions of the water content and pore-water pressure in ground around the leakage pipelines. The leakage pipeline being modeled as an injection well, a series of unsteady seepage numerical analysis is performed to understand the effects of the internal water pressure of pipelines on the range of saturated ground surrounding the pipelines, and computation results show the exponential relationship between them. In the unsteady seepage analysis, the hydraulic conductivity function and the volumetric water content function must be determined beforehand to get reasonable results of the range of saturated ground.

scholarly journals An efficient workflow to accurately compute groundwater recharge for the study of rainfall-triggered deep-seated landslides, application to the Séchilienne unstable slope (western Alps)

2015 ◽  
Vol 19 (1) ◽  
pp. 427-449 ◽  
Author(s):  
A. Vallet ◽  
C. Bertrand ◽  
O. Fabbri ◽  
J. Mudry
Keyword(s):  
Groundwater Recharge ◽  
Pore Water ◽  
Spatial Data ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Western Alps ◽  
Aerial Photographs ◽  
Coefficient Of Determination ◽  
Recharge Area ◽  
Hydrodynamic Behaviour

Abstract. Pore water pressure build-up by recharge of underground hydrosystems is one of the main triggering factors of deep-seated landslides. In most deep-seated landslides, pore water pressure data are not available since piezometers, if any, have a very short lifespan because of slope movements. As a consequence, indirect parameters, such as the calculated recharge, are the only data which enable understanding landslide hydrodynamic behaviour. However, in landslide studies, methods and recharge-area parameters used to determine the groundwater recharge are rarely detailed. In this study, the groundwater recharge is estimated with a soil-water balance based on characterisation of evapotranspiration and parameters characterising the recharge area (soil available water capacity, runoff and vegetation coefficient). A workflow to compute daily groundwater recharge is developed. This workflow requires the records of precipitation, air temperature, relative humidity, solar radiation and wind speed within or close to the landslide area. The determination of the parameters of the recharge area is based on a spatial analysis requiring field observations and spatial data sets (digital elevation models, aerial photographs and geological maps). This study demonstrates that the performance of the correlation with landslide displacement velocity data is significantly improved using the recharge estimated with the proposed workflow. The coefficient of determination obtained with the recharge estimated with the proposed workflow is 78% higher on average than that obtained with precipitation, and is 38% higher on average than that obtained with recharge computed with a commonly used simplification in landslide studies (recharge = precipitation minus non-calibrated evapotranspiration method).

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