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.

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 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 Experimental insights into consolidation rates during one-dimensional loading with special reference to excess pore water pressure

2020 ◽  
Vol 15 (12) ◽  
pp. 3571-3591
Author(s):  
Bartłomiej Szczepan Olek
Keyword(s):  
Pore Water ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Small Scale ◽  
Coefficient Of Consolidation ◽  
Consolidation Process ◽  
Factors Affecting ◽  
Fine Grained ◽  
Fine Grained Soil

AbstractConsolidation rate has significant influence on the settlement of structures founded on soft fine-grained soil. This paper presents the results of a series of small-scale and large-scale Rowe cell consolidation tests with pore water pressure measurements to investigate the factors affecting the consolidation process. Permeability and creep/resistance structure factors were considered as the governing factors. Intact and reconstituted marine clay from the Polish Carpathian Foredeep basin as well as clay–sand mixtures was examined in the present study. The fundamental relationship correlating consolidation degrees based on compression and pore water pressure was assessed to indicate the nonlinear soil behaviour. It was observed that the instantaneous consolidation parameters vary as the process progresses. The instantaneous coefficient of consolidation first drastically increases or decreases with increase in the degree of consolidation and stabilises in the middle stage of the consolidation; it then decreases significantly due to viscoplastic effects occurring in the soil structure. Based on the characteristics of the relationship between coefficient of consolidation and degree of dissipation at the base, the consolidation range that complies with theoretical assumptions was established. Furthermore, the influence of coarser fraction in clay–sand mixtures in controlling the consolidation rates is discussed.

Physical environment of drumlin formation

1995 ◽  
Vol 41 (137) ◽  
pp. 30-38 ◽  
Author(s):  
Carrie J. Patterson ◽  
Roger LeB. Hooke
Keyword(s):  
Pore Water ◽  
Physical Environment ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Transverse Strain ◽  
Strain Rates

AbstractReview of published descriptions of drumlin fields suggests that the following conditions are important to drumlin growth: (1) compressive longitudinal and possibly extending transverse strain rates in the ice, (2) thin ice such as occurs near the glacier margin, and (3) high pore-water pressure in the subglacial sediments. Most drumlin fields display all of these, and no fields of well-developed drumlins were found that did not. On the oilier hand, the lithology of drumlin-forming sediment appears not to be important in promoting drumlin growth, since it varied widely, nor are the lithology and large-scale topography of the bed.

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.

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.

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.

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