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 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 Studies on Three-Dimensional (3D) Modeling of UAV Oblique Imagery with the Aid of Loop-Shooting

2018 ◽  
Vol 7 (9) ◽  
pp. 356 ◽  
Author(s):  
Jia Li ◽  
Yongxiang Yao ◽  
Ping Duan ◽  
Yun Chen ◽  
Shuang Li ◽  
...  
Keyword(s):  
3D Modeling ◽  
Large Scale ◽  
3D Model ◽  
Three Dimensional ◽  
Scale Model ◽  
Scene Modeling ◽  
Standard Scale ◽  
Large Scale Model ◽  
City Construction ◽  
Key Steps

Oblique imagery obtained from an Unmanned Aerial Vehicle (UAV) has been widely applied to large-scale three-dimensional (3D) reconstruction; however, the problems of partially missing model details caused by such factors as occlusion, distortion, and airflow, are still not well resolved. In this paper, a loop-shooting-aided technology is used to solve the problem of details loss in the 3D model. The use of loop-shooting technology can effectively compensate for losses caused by occlusion, distortion, or airflow during UAV flight and enhance the 3D model details in large scene- modeling applications. Applying this technology involves two key steps. First, based on the 3D modeling construction process, the missing details of the modeling scene are found. Second, using loop-shooting image sets as the data source, incremental iterative fitting based on aerotriangulation theory is used to compensate for the missing details in the 3D model. The experimental data used in this paper were collected from Yunnan Normal University, Chenggong District, Kunming City, Yunnan Province, China. The experiments demonstrate that loop-shooting significantly improves the aerotriangulation accuracy and effectively compensates for defects during 3D large-scale model reconstruction. In standard-scale distance tests, the average relative accuracy of our modeling algorithm reached 99.87% and achieved good results. Therefore, this technique not only optimizes the model accuracy and ensures model integrity, but also simplifies the process of refining the 3D model. This study can be useful as a reference and as scientific guidance in large-scale stereo measurements, cultural heritage protection, and smart city construction.

A Large-Scale Model Developed for Predicting the Corroding Conditions of a Carrier Pipe in a Casing

2012 ◽  
Author(s):  
Fengmei Song ◽  
Andrew Nordquist
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Scale Model ◽  
Coating Quality ◽  
Metallic Contact ◽  
Internal Surfaces ◽  
Voltage Variation ◽  
Large Scale Model ◽  
Pipe Segment ◽  
Industry Needs

The corroding conditions of a cased carrier pipe segment are difficult to measure in the field. It is hard to know whether or how well the cased pipe segment is cathodically protected. The pipeline industry needs a tool that can predict the in-situ corrosion potential of the carrier pipe in the casing annulus in order to determine the level of cathodic protection (CP). This work reports on a large-scale, three-dimensional computer model developed to make such a prediction. The casing wall may be treated as bare or coated on both or either of the external and internal surfaces. The carrier pipe is coated, and the coating quality inside the annulus may or may not be the same as the outside of the casing segment. The casing annulus is full of electrolytes. The model is used to investigate the effect of several factors on the level of CP imposed on the carrier pipe in the annulus, including the coating quality on the carrier pipe, the casing wall native potentials (both external and internal), the presence of a coating on a casing wall surface, and a metallic contact (between the casing and the carrier pipe) with the contact resistance being a variable. The effect of the voltage variation inside the pipe metal wall is also investigated.

Reconciling Juno and past mission datasets to improve large-scale models of radiation-belt electron and radio emission distributions at Jupiter

2021 ◽  
Author(s):  
Daniel Santos-Costa ◽  
Frederic Allegrini ◽  
Rob Wilson ◽  
Peter Kollmann ◽  
George Clark ◽  
...  
Keyword(s):  
Radio Emission ◽  
Large Scale ◽  
Three Dimensional ◽  
Planck Equation ◽  
Radiation Belts ◽  
Scale Model ◽  
Data Sets ◽  
Electron Radiation ◽  
Large Scale Model ◽  
Electron Distributions

<p>We present our latest model of electron radiation belts developed for a large region of Jupiter's magnetosphere (1-50 Rj). For the region inward of Io, electron distributions are computed from a computational code that solves the governing three-dimensional Fokker-Planck equation. This physics-based model accounts for different mechanisms to discuss the energy and spatial distributions of electrons for L values between 1 and 5. The model for the innermost magnetospheric region is expanded to the middle magnetosphere using an empirical approach. In this paper, we first show how our large-scale model of Jupiter's electron radiation belts agrees with data sets from past missions (Pioneer 10 and 11 GTT, Galileo EPD and EPI measurements). We then focus on our effort to combine Juno (JEDI, JADE Electron Ambient Background Counts) and Galileo EPD (> 1.5, 11.5 MeV) datasets to improve our model for both the region beyond Io and the inner edge of the Jovian electron radiation belts. Finally, simulations of Jupiter's synchrotron emission are presented to gauge the contribution of ultra-energetic electrons trapped beyond L ~ 3 at different latitudes to radio emission observed by Juno MWR.</p>

Experimental study of three-dimensional separation on a large-scale model

AIAA Journal ◽  
1995 ◽  
Vol 33 (11) ◽  
pp. 2107-2113 ◽  
Author(s):  
D. Barberis ◽  
P. Molton
Keyword(s):  
Experimental Study ◽  
Large Scale ◽  
Three Dimensional ◽  
Scale Model ◽  
Large Scale Model

Mechanism Analysis and Experimental Study of Soil-Compacting by Silent Piling

2012 ◽  
Vol 170-173 ◽  
pp. 457-460
Author(s):  
Fu Rong Li ◽  
Hou Chao Sun ◽  
Zhao Yu Wang
Keyword(s):  
Pore Water ◽  
Soil Compaction ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Radial Distance ◽  
Scale Model ◽  
Single Pile ◽  
Mechanism Analysis

The mechanism of soil-compacting effect by silent piling is analyzed, and based on large-scale model box test, using soft clay of typical sites in Yancheng District, taking the single pile as the study objects respectively, and studying the soil compaction effects with the process of sinking into the single pile, analyzing the variation law of the soil deformation and pore water pressure while sinking into the single pile. The results shows that the greater the radial distance, the smaller of soil compaction effect, the influence scope of soil compaction effects on the displacement and pore water pressure reaches 0.6 times and 0.5 times the pile length sinking the single pile, which is accord to the actual engineering. The results could guide the pile foundation construction on soft soil.

RANCANG BANGUN PERANGKAT EKSPERIMENTASI PROSES PIROLISIS BIOMASA GELOMBANG MIKRO

2013 ◽  
Vol 14 (2) ◽  
Author(s):  
Noor Fachrizal
Keyword(s):  
Large Scale ◽  
Continuous Model ◽  
Biomass Energy ◽  
Scale Model ◽  
Small Scale ◽  
Laboratory Apparatus ◽  
Liquid Form ◽  
Large Scale Model ◽  
Bio Oil ◽  
Pyrolysis Of Biomass

Biomass such as agriculture waste and urban waste are enormous potency as energy resources instead of enviromental problem. organic waste can be converted into energy in the form of liquid fuel, solid, and syngas by using of pyrolysis technique. Pyrolysis process can yield higher liquid form when the process can be drifted into fast and flash response. It can be solved by using microwave heating method. This research is started from developing an experimentation laboratory apparatus of microwave-assisted pyrolysis of biomass energy conversion system, and conducting preliminary experiments for gaining the proof that this method can be established for driving the process properly and safely. Modifying commercial oven into laboratory apparatus has been done, it works safely, and initial experiments have been carried out, process yields bio-oil and charcoal shortly, several parameters are achieved. Some further experiments are still needed for more detail parameters. Theresults may be used to design small-scale continuous model of productionsystem, which then can be developed into large-scale model that applicable for comercial use.

scholarly journals The Hydromechanical Interplay in the Simplified Three-Dimensional Limit Equilibrium Analyses of Unsaturated Slope Stability

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 73
Author(s):  
Panagiotis Sitarenios ◽  
Francesca Casini
Keyword(s):  
Analytical Solution ◽  
Slope Stability ◽  
Slope Failure ◽  
Failure Modes ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Three Dimensional ◽  
Stability Limit ◽  
Smooth Transition

This paper presents a three-dimensional slope stability limit equilibrium solution for translational planar failure modes. The proposed solution uses Bishop’s average skeleton stress combined with the Mohr–Coulomb failure criterion to describe soil strength evolution under unsaturated conditions while its formulation ensures a natural and smooth transition from the unsaturated to the saturated regime and vice versa. The proposed analytical solution is evaluated by comparing its predictions with the results of the Ruedlingen slope failure experiment. The comparison suggests that, despite its relative simplicity, the analytical solution can capture the experimentally observed behaviour well and highlights the importance of considering lateral resistance together with a realistic interplay between mechanical parameters (cohesion) and hydraulic (pore water pressure) conditions.

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