Evaluation of the Grouting Effect of the Change of Grout Hole Spacing in Splitting Grouting for Dams

2012 ◽  
Vol 151 ◽  
pp. 295-299
Author(s):  
Ke Wu ◽  
Ming Yue Ma
Keyword(s):  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Stress And Strain ◽  
Dam Construction ◽  
Construction Process ◽  
Distribution Law ◽  
Technological Standard ◽  
The Stability

The technique of splitting grouting for dams is one of the important technical approaches to improve the inner quality of dam construction. However, the construction cost is too high with the current technological standard, which restricts the further promotion of this technology. Based on the assumption that the other conditions of construction process remained unchanged and by obeying the law of interaction between the placement of grout-hole spacing and the actual anti-seepage effect during splitting grouting, Mohr-Coulomb Hardening constitutive model was adopted in this paper on the basis of large-scale finite element numerical algorithm. Through the fluid-solid coupling computation of grout holes of different spacing, the distribution law of various factors during splitting grouting, such as the pore water pressure generated by seriflux and the stress and strain of dam, was studied first. Next, the mechanism of reinforcement and seepage of splitting grouting seriflux in soil body was revealed, and the influence of this mechanism on the stability of dam body was also investigated. Finally, the effect of splitting grouting was evaluated.

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 Integrated Simulation Modeling Approach for Investigating Pore Water Pressure Induced Landslides

2022 ◽  
Author(s):  
Sahila Beegum ◽  
P J Jainet ◽  
Dawn Emil ◽  
K P Sudheer ◽  
Saurav Das
Keyword(s):  
Pore Water ◽  
Factor Of Safety ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Simulation Models ◽  
Integrated Simulation ◽  
Hill Slope ◽  
Slope Factor ◽  
The Stability ◽  
The Hill

Abstract Soil pore water pressure analysis is crucial for understanding landslide initiation and prediction. However, field-scale transient pore water pressure measurements are complex. This study investigates the integrated application of simulation models (HYDRUS-2D/3D and GeoStudio–Slope/W) to analyze pore water pressure-induced landslides. The proposed methodology is illustrated and validated using a case study (landslide in India, 2018). Model simulated pore water pressure was correlated with the stability of hillslope, and simulation results were found to be co-aligned with the actual landslide that occurred in 2018. Simulations were carried out for natural and modified hill slope geometry in the study area. The volume of water in the hill slope, temporal and spatial evolution of pore water pressure, and factor of safety were analysed. Results indicated higher stability in natural hillslope (factor of safety of 1.243) compared to modified hill slope (factor of safety of 0.946) despite a higher pore water pressure in the natural hillslope. The study demonstrates the integrated applicability of the physics-based models in analyzing the stability of hill slopes under varying pore water pressure and hill slope geometry and its accuracy in predicting future landslides.

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 Environmental impact of intensive farming in sloping areas

2018 ◽  
Vol 174 ◽  
pp. 01001
Author(s):  
Giovanni Bosco ◽  
Lucia Simeoni
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Sprinkler Irrigation ◽  
High Yield ◽  
Qualitative And Quantitative ◽  
Intensive Farming ◽  
Yield Production ◽  
Large Water ◽  
The Stability ◽  
Irrigation Runoff

The increased demand for food causes intensive farming with high yield production and large water consumption to extend significantly. Depending on soil properties, seasonal rainfall, surface drainage and water resources, hence the consumption-infiltration balance, the ground water table might be raised or depleted; soils could be saturated or remain partly saturated with negative pore pressures. As a result sloping grounds may become prone to shallow slides, as mudflows, or deep seated movements, involving large volumes of soil, especially after rupture of major watering lines or after long uncontrolled irrigations. Within this framework the paper investigates the possible effects of replacing grassland with intensive apple farming on the stability conditions of slopes. Apples require frequent watering, especially during spring and summer to meet qualitative and quantitative productive standards. Also, sprinkler irrigation is often used to protect against hail. From the precipitation, irrigation, runoff, evaporation and plant transpiration balance, the evolution of the pore water pressure distribution within an average year is calculated. Then the modified shear strength of the unsaturated-saturated soils is determined and the factor of safety against sliding is calculated.

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.

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.

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.

Hard Clay as Host Medium Thermo-Mechanical Experiments and Model

1985 ◽  
Vol 50 ◽  
Author(s):  
G. Baldi ◽  
M. Borsetto ◽  
T. Hueckel ◽  
A. Peano ◽  
E. Tassoni
Keyword(s):  
Dissipation Rate ◽  
Pore Water Pressure ◽  
Essential Feature ◽  
Water Pressure ◽  
Pressure Rise ◽  
Computer Code ◽  
Host Medium ◽  
Clay Formation ◽  
The Mathematical Model

AbstractClay's impermeability is an essential feature for the quality of a possible repository. However it results in a substantial pore water pressure rise induced by heating whose magnitude and dissipation rate depend on the clay's deformational response to heating. Experiments on thermal strains and effective stress are reported and the mathematical model implemented in a computer code is described. It allows study of a repository performance due to waste heating in both continental and subseabed clay formation.

scholarly journals New technique for predicting the pore water pressure and evaluating the stability of rock-fill dam during impounding

2007 ◽  
Vol 49 (1) ◽  
pp. 3-15
Author(s):  
Yasuo YANAKA ◽  
Akira TAKAHASHI ◽  
Yoshinobu HOS H INO ◽  
Tomokazu SUZUKI ◽  
Makoto NISHIGAKI ◽  
...  
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
New Technique ◽  
Rock Fill ◽  
The Stability

Construction Analysis of the Chimney of Solar Thermal Power Station

2013 ◽  
Vol 283 ◽  
pp. 41-46
Author(s):  
Shao Wen Fang ◽  
Xing Fei Yuan
Keyword(s):  
Large Scale ◽  
Thermal Power ◽  
Load Condition ◽  
Initial Imperfection ◽  
Internal Force ◽  
Construction Process ◽  
Buckling Mode ◽  
A Value ◽  
Gravity Load ◽  
The Stability

A 100MW solar chimney is high as one thousand meters, belonging to ultra-high-rise structure. Considering the complicated load condition, the large scale and long period of construction process, construction analysis is important to the structure. Using element birth and death technology in ANSYS, the whole construction process is simulated in this paper. Numerical results indicate that the deformation and internal force of the structure change a lot during the construction process. Great differences exist in property and magnitude between construction status and design status. To investigate the stability of the structure under wind and gravity load, the first eigen buckling mode with a value of L/300 and construction deformation are considered as initial imperfection respectively. The results show the ultimate bearing capacity of the structure considering construction deformation is lower than that considering the first-order initial imperfection.

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