Temporal changes of groundwater pressure in a natural slope of nonfissured clay

1984 ◽  
Vol 21 (1) ◽  
pp. 138-146 ◽  
Author(s):  
T. C. Kenney ◽  
K. C. Lau
Keyword(s):  
Safety Factor ◽  
Soft Clay ◽  
Ground Surface ◽  
Field Measurements ◽  
Test Site ◽  
Field Investigation ◽  
Direct Result ◽  
Natural Slope ◽  
Hydraulic Conditions

This paper presents results from a field investigation in which groundwater pressures were measured in a natural slope of soft clay over a 10 year period. Measurements of piezometric levels are reported together with calculated annual changes of safety factor of the slope.Using consolidation theory, predictions were made of changes of piezometric levels for the condition of zero infiltration based on the postulate that these changes were the direct result of changes of hydraulic conditions at the ground surface. The predictions were in agreement with the field measurements.A method is suggested for estimating the most severe groundwater pressures that a clay slope can be expected to experience. Using this method, estimates were made of the minimum expected value of safety factor of the slope at the test site. Keywords: natural slope, clay, pore pressures, field measurements, stability, long-term.

Analysis of radionuclide migration with consideration of spatial and temporal change of migration parameters due to uplift and denudation

2015 ◽  
Vol 1744 ◽  
pp. 229-234
Author(s):  
Taro Shimada ◽  
Seiji Takeda ◽  
Masayuki Mukai ◽  
Masahiro Munakata ◽  
Tadao Tanaka
Keyword(s):  
Ground Water ◽  
Flow Velocity ◽  
Safety Assessment ◽  
Ground Surface ◽  
Disposal Site ◽  
Radionuclide Migration ◽  
Water Flow Velocity ◽  
Term Change ◽  
Hydraulic Conditions

ABSTRACTIntegrated safety assessment methodology that analyzes radionuclide migration reflecting the spatial and temporal changes of disposal systems was developed for a geological disposal site with uplift and denudation, and then some case analyses for an assumed site were carried out. The combination of uniform uplift and denudation has the largest effect on the radionuclide migration because the ground water flow velocity increases with decreasing depth from the ground surface. In the case without denudation, tilted uplift has more effect than uniform uplift because flow velocity in tilted uplift increases with increasing hydraulic gradient. The long-term change of the geological structures including the uplift and denudation, the hydraulic conditions, and the recharge and outlet of the ground water around a candidate site should be carefully investigated to determine the appropriate the place, depth and layout of the repository.

Evaluation of Alluvial Channels Meandering Phenomenon (Case Study: Bahr Youssef)

2017 ◽  
Vol 17 (2) ◽  
pp. 206-219
Author(s):  
Mohamed A. Ashour ◽  
M. Sherif Saad ◽  
Mustafa M. Kotb
Keyword(s):  
Field Measurements ◽  
Direct Result ◽  
Accurate Estimation ◽  
Nile Valley ◽  
Alluvial Channels ◽  
The West ◽  
Easy Method ◽  
Hydraulic Conditions ◽  
Deposition Processes

AbstractBahr Youssef (B.Y) is a semi-natural branch canal connecting the River Nile with Fayoum depression, in the desert immediately to the west of the Nile Valley, about 92 kilometers southwest of Cairo, for irrigation purposes of El-Minya, El-Fayoum, Bani-Swif, and Giza governorates. The area served by Bahr Youssef reaches about 850.000 feds in the Middle Egypt, out of 1.650.000 feds served by the Ibrahimeya carrier canal, which branches from the River Nile's at Assiut barrage, and extends northward for 55 kilometers, until Dayrut city. In Dayrut; “Ibrahimeya” canal bifurcates into seven carrier canals, (Bahr Youssef is one of them,) through Dayrut Group of regulators. Bahr Youssef suffers from, meandering phenomenon, in many reaches, occurred with all its harmful and destructive effects. As meanders are the direct result of erosion-deposition processes occur in such flatty reaches with hydraulically unstable sections, our effort here is directed for studying the existing geometric, and hydraulic conditions of some representative reaches of Bahr Youssef, to evaluate the size of the problem through intensive field measurements, and to verify the available predicting techniques and theories by comparison with the obtained measured values. Introducing an acceptable, effective and easy method, which can be used for an accurate estimation of the meandering phenomenon, is the main objective of this study. This was achieved through reviewing and assessment of the available predicting techniques, and evaluating their liability, validity, and suitability through the comparison with the field collected measurements.

scholarly journals Sediment Transport and Water Flow Resistance in Alluvial River Channels: Modified Model of Transport of Non-Uniform Grain-Size Sediments

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2038
Author(s):  
Gennady Gladkov ◽  
Michał Habel ◽  
Zygmunt Babiński ◽  
Pakhom Belyakov
Keyword(s):  
Sediment Transport ◽  
Water Flow ◽  
Transport Model ◽  
Flow Characteristics ◽  
Field Measurements ◽  
Field Investigation ◽  
Empirical Modeling ◽  
River Channels ◽  
Channel Deformations ◽  
East European

The paper presents recommendations for using the results obtained in sediment transport simulation and modeling of channel deformations in rivers. This work relates to the issues of empirical modeling of the water flow characteristics in natural riverbeds with a movable bottom (alluvial channels) which are extremely complex. The study shows that in the simulation of sediment transport and calculation of channel deformations in the rivers, it is expedient to use the calculation dependences of Chézy’s coefficient for assessing the roughness of the bottom sediment mixture, or the dependences of the form based on the field investigation data. Three models are most commonly used and based on the original formulas of Meyer-Peter and Müller (1948), Einstein (1950) and van Rijn (1984). This work deals with assessing the hydraulic resistance of the channel and improving the river sediment transport model in a simulation of riverbed transformation on the basis of previous research to verify it based on 296 field measurements on the Central-East European lowland rivers. The performed test calculations show that the modified van Rijn formula gives the best results from all the considered variants.

scholarly journals Observations of Tidal Flat Sedimentation within a Native and an Exotic Spartina Species

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1566
Author(s):  
Barbara Proença ◽  
Florian Ganthy ◽  
Richard Michalet ◽  
Aldo Sottolichio
Keyword(s):  
Single Point ◽  
Field Measurements ◽  
Species Variation ◽  
Storm Events ◽  
Level Variation ◽  
Wave Forcing ◽  
Bed Elevation ◽  
Sediment Stabilization ◽  
Consistent Response

Field measurements of bed elevation and related wave events were performed within a tidal marsh, on two cordgrass species, Spartina anglica (exotic) and Spartina maritima (native), in the Bay of Arcachon (SW France). Bed- and water-level time series were used to infer on the sediment behavior patterns from short to long term. A consistent response was found between the bed-level variation and the wave forcing, with erosion occurring during storms and accretion during low energy periods. Such behavior was observed within the two species, but the magnitude of bed-level variation was higher within the native than the exotic Spartina. These differences, in the order of millimeters, were explained by the opposite allocation of biomass of the two species. On the long term, the sedimentation/erosion patterns were dominated by episodic storm events. A general sediment deficit was observed on the site, suggested by an overall bed-level decrease registered within both species. However, further verification of within species variation needs to be considered when drawing conclusions. Despite possible qualitative limitations of the experimental design, due to single point survey, this work provides original and considerable field data to the understanding the different species ability to influence bed sediment stabilization and their potential to build marsh from the mudflat pioneer stage. Such information is valuable for coastal management in the context of global change.

scholarly journals Field Investigation and Rapid Deterioration Analysis of Heavy Haul Corrugation

2021 ◽  
Vol 11 (14) ◽  
pp. 6317
Author(s):  
Feng Jin ◽  
Hong Xiao ◽  
Mahantesh M Nadakatti ◽  
Huiting Yue ◽  
Wanting Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Cracks ◽  
Field Measurements ◽  
Field Investigation ◽  
The Finite Element Method ◽  
Rail Corrugation ◽  
Rapid Deterioration ◽  
Heavy Haul

In this study, the rapid growth of corrugation caused by the bad quality of grinding works and their wavelength, depth, and evolution processes are captured through field measurements. The residual grinding marks left by poor grinding quality lead to further crack accumulation and corrugation deterioration by decreasing plastic resistance in rails. In this case, the average peak-to-peak values of corrugation grow extremely fast, reaching 1.4 μm per day. The finite element method (FEM) and fracture mechanics methodologies were used to analyze the development and trends in rail surface crack deterioration by considering rails with and without grinding marks. Crack propagation trends increase with residual grinding marks, and they are more severe in circular curve lines. To avoid the rapid deterioration of rail corrugation, intersections between grinding marks and fatigue cracks should be avoided.

scholarly journals Health and sustainability of glaciers in High Mountain Asia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Evan Miles ◽  
Michael McCarthy ◽  
Amaury Dehecq ◽  
Marin Kneib ◽  
Stefan Fugger ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Field Measurements ◽  
Tien Shan ◽  
High Mountain ◽  
Specific Mass ◽  
Ice Flow ◽  
Ice Volume ◽  
Mass Redistribution ◽  
Glacier Ablation

AbstractGlaciers in High Mountain Asia generate meltwater that supports the water needs of 250 million people, but current knowledge of annual accumulation and ablation is limited to sparse field measurements biased in location and glacier size. Here, we present altitudinally-resolved specific mass balances (surface, internal, and basal combined) for 5527 glaciers in High Mountain Asia for 2000–2016, derived by correcting observed glacier thinning patterns for mass redistribution due to ice flow. We find that 41% of glaciers accumulated mass over less than 20% of their area, and only 60% ± 10% of regional annual ablation was compensated by accumulation. Even without 21st century warming, 21% ± 1% of ice volume will be lost by 2100 due to current climatic-geometric imbalance, representing a reduction in glacier ablation into rivers of 28% ± 1%. The ablation of glaciers in the Himalayas and Tien Shan was mostly unsustainable and ice volume in these regions will reduce by at least 30% by 2100. The most important and vulnerable glacier-fed river basins (Amu Darya, Indus, Syr Darya, Tarim Interior) were supplied with >50% sustainable glacier ablation but will see long-term reductions in ice mass and glacier meltwater supply regardless of the Karakoram Anomaly.

scholarly journals HGG-47. DECREASED GROWTH VELOCITY WITH LONG TERM USE OF BRAFV600e AND MEK INHIBITION IN A PATIENT WITH ANAPLASTIC GANGLIOGLIOMA

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii352-iii352
Author(s):  
Hung Tran ◽  
Robert Cooper
Keyword(s):  
Growth Velocity ◽  
Direct Result ◽  
Chromosomal Microarray ◽  
Mek Inhibition ◽  
Follow Up Study ◽  
The Family ◽  
The Relationship

Abstract PURPOSE To describe decreased growth velocity with long term use of BRAFV600e and MEK inhibition in a patient with anaplastic ganglioglioma. RESULTS 4-year-old patient was found to have a 6 x 4.6 x 5 cm mass in the hypothalamus. Pathology consistent with anaplastic ganglioglioma and chromosomal microarray revealed a BRAFV600e mutation. Patient started on dabrafenib and trametinib and tumor decreased 85% after 3 months. She is stable without significant toxicities 39 months on therapy, and is now 8 years old. Patient had been growing at the 25% for weight and 12% for height but is now 65% for weight and 0.5% for height. It is difficult to tease out the relationship between the tumor, the location of the tumor, and the BRAF and MEK inhibitors and their effect on growth. Discussions with the family and endocrinology are ongoing but being <1% for height will lead to decrease in quality of life. CONCLUSIONS Further follow-up study is needed to determine if this is truly a long-term toxicity, or if this may just be a direct result of the location of the tumor. Would supplementation with growth hormone in this patient lead to losing control of a high grade tumor, or would it simply replace a hormone that is not produced?

Contrôle de la stabilité des remblais par la mesure des déplacements horizontaux

1974 ◽  
Vol 11 (1) ◽  
pp. 182-201 ◽  
Author(s):  
René Marche ◽  
Robert Chapuis
Keyword(s):  
Factor Of Safety ◽  
Soft Clay ◽  
Ground Surface ◽  
Soft Layer ◽  
The Stability ◽  
Horizontal Displacements

The horizontal displacements measured at the toe of eight embankments are analyzed as a function of the factor of safety. The embankments are built on layers of soft clay. Only the undrained stage is studied.When the factor of safety of the embankments is higher than about 1.4, the horizontal displacements on the ground surface, at the toe of the embankment seem to follow an elastic law which is highly dependent on the ratio of the thickness of the soft layer to the width of the embankment. When the factor of safety is lower than about 1.4, the horizontal displacements do not follow an elastic law, they increase considerably. Consequently, it is suggested that the horizontal displacements be precisely measured at the toe of embankments during construction. These measurements are simple and sensitive to the approach of failure, they can be efficiently used to control the stability of embankments. This study also gives some information concerning the variation of horizontal displacements versus depth.

scholarly journals Performance of Norton Quantum Grinding Wheels

2016 ◽  
Vol 686 ◽  
pp. 125-130 ◽  
Author(s):  
Miroslav Neslušan ◽  
Jitka Baďurová ◽  
Anna Mičietová ◽  
Maria Čiliková
Keyword(s):  
Surface Roughness ◽  
Ground Surface ◽  
Bearing Steel ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Grinding Forces ◽  
Removal Rates ◽  
Surface Burn ◽  
Conventional Grinding

This paper deals with cutting ability of progressive Norton Quantum grinding wheel during grinding roll bearing steel 100Cr6 of hardness 61 HRC. Cutting ability of this wheel is compared with conventional grinding wheel and based on measurement of grinding forces as well as surface roughness. Results of experiments show that Norton Quantum grinding wheels are capable of long term grinding cycles at high removal rates without unacceptable occurrence of grinding chatter and surface burn whereas application of conventional wheel can produce excessive vibration and remarkable temper colouring of ground surface. Moreover, while Norton Quantum grinding wheel gives nearly constant grinding forces and surface roughness within ground length at higher removal rates, conventional grinding wheel (as that reported in this study) does not.

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