scholarly journals A numerical analysis of how permeability affects the development of pore water pressure in early age cemented paste backfill in a backfilled stope

2014 ◽  
Author(s):  
Ryan Veenstra ◽  
Murray Grabinsky ◽  
William Bawden ◽  
Ben Thompson
Keyword(s):  
Numerical Analysis ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Early Age ◽  
Cemented Paste Backfill ◽  
Paste Backfill

Investigation of some controllable factors that impact the stress state in cemented paste backfill

2015 ◽  
Vol 52 (12) ◽  
pp. 1901-1912 ◽  
Author(s):  
James P. Doherty ◽  
Alsidqi Hasan ◽  
Gonzalo H. Suazo ◽  
Andy Fourie
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Cement Content ◽  
Water Pressure ◽  
Cemented Paste Backfill ◽  
Total Stress ◽  
Rest Periods ◽  
Rate Of Increase ◽  
Controllable Factors ◽  
Paste Backfill

This paper presents in-stope measurements of total stress and pore-water pressure at strategic locations within three underground stopes at the Raleigh mine site (Western Australia) that were filled with cemented paste backfill (CPB). The three stopes were very similar in shape. Key differences among the stopes were the filling and resting schedules, the barricade drainage systems used, and the cement content of the CPB. Data from the stopes are compared to determine which controllable factors most significantly influence barricade pressures during and after filling. The most significant factor was the scheduling of rest periods between filling, with even very short pauses in filling dramatically reducing the rate of increase of pore-water pressure and total stress with increasing height of fill.

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.

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.

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.

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.

TIME TO THE END OF PRIMARY CONSOLIDATION (EOP) OF SOFT CLAYEY SOILS: CONCERNING THE EFFECT OF ATTERBERG’S LIMIT AND CYCLIC LOADING HISTORY

2019 ◽  
Vol 128 (2B) ◽  
pp. 29-41
Author(s):  
Trần Thanh Nhàn
Keyword(s):  
Cyclic Loading ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Clayey Soils ◽  
Loading History ◽  
Cyclic Shear ◽  
Wide Range ◽  
Primary Consolidation ◽  
Time Required

In order to observe the end of primary consolidation (EOP) of cohesive soils with and without subjecting to cyclic loading, reconstituted specimens of clayey soils at various Atterberg’s limits were used for oedometer test at different loading increments and undrained cyclic shear test followed by drainage with various cyclic shear directions and a wide range of shear strain amplitudes. The pore water pressure and settlement of the soils were measured with time and the time to EOP was then determined by different methods. It is shown from observed results that the time to EOP determined by 3-t method agrees well with the time required for full dissipation of the pore water pressure and being considerably larger than those determined by Log Time method. These observations were then further evaluated in connection with effects of the Atterberg’s limit and the cyclic loading history.

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