Research on the Permeability of Concrete under the High Water Pressure

2013 ◽  
Vol 838-841 ◽  
pp. 1797-1800
Author(s):  
Bing Hua Zhao ◽  
Shi Ping Zhang
Keyword(s):  
Water Pressure ◽  
Laboratory Data ◽  
Influence Factors ◽  
High Water ◽  
Software Simulation ◽  
Water Head ◽  
Concrete Permeability ◽  
Practical Engineering ◽  
Variable Water ◽  
Permeability Structure

Seepage is important influence factors of degradation and instability to the water or under water concrete structure, it is also the difficult point in geotechnical engineering research.Through the concrete seepage experiment，combined with the Seep/W module of GeoStudio software，simulation of unsteady seepage of concrete，it was obtained that the seepage field under the action of a variable water head in 24 hr,And the results were compared with laboratory data，For further research on concrete permeability structure in practical engineering, foundation stability and durability.

scholarly journals Short-term Variations in Strain and Surface Tilt on Storglaciären, Kebnekaise, Northern Sweden

1989 ◽  
Vol 35 (120) ◽  
pp. 201-208 ◽  
Author(s):  
Peter Jansson ◽  
Roger LeB. Hooke
Keyword(s):  
Water Pressure ◽  
High Water ◽  
Ice Thickness ◽  
Gradual Change ◽  
Short Term ◽  
Glacier Surface ◽  
Vertical Movements ◽  
Bed Topography ◽  
The Waves ◽  
Local Uplift

AbstractTiltmeters that can detect changes in slope of a glacier surface as small as 0.1 μ rad have been used on Storglaciären. The records obtained to date have been from the upper part of the ablation area, where the bed of the glacier is overdeepened. A total of 82 d of records has been obtained for various time periods between early June and early September.There is generally a gradual change in inclination of the glacier surface over periods of several days, but these changes do not appear to be systematic. In particular, they are not consistent with vertical movements of stakes located 2–3 ice thicknesses away from the tiltmeters. This suggests that the tiltmeters are sensing disturbances over areas with diameters comparable to the local ice thickness.Superimposed on these trends are diurnal signals suggesting rises and falls of the surface just up-glacier from the riegel that bounds the overdeepening on its down-glacier end. These may be due to waves of high water pressure originating in a crevassed area near the equilibrium line. If this interpretation is correct, the waves apparently move down-glacier at speeds of 20–60 m h−1and become sufficiently focused, either by the bed topography or by conduit constrictions, to result in local uplift of the surface. Also observed are abrupt tilts towards the glacier center line shortly after the beginning of heavy rainstorms. These appear to be due to longitudinal stretching as the part of the glacier below the riegel accelerates faster than that above. Water entering the glacier by way of a series of crevasses over the riegel is believed to be responsible for this differential acceleration. In June 1987, a dramatic event was registered, probably reflecting the initial summer acceleration of the glacier.

scholarly journals Cutting Resistance Laboratory Testing Methodology for Underwater Coal Mining

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 564
Author(s):  
Vladimir Čebašek ◽  
Veljko Rupar ◽  
Stevan Đenadić ◽  
Filip Miletić
Keyword(s):  
Coal Mining ◽  
Laboratory Testing ◽  
Water Pressure ◽  
Laboratory Data ◽  
Working Environment ◽  
Laboratory Research ◽  
Surrounding Water ◽  
Cutting Resistance ◽  
Testing Methodology

The bucket-wheel dredge “Kovin I” for underwater coal mining with bucket-wheel type UCW-450 has been in operation for over 20 years. Based on analyzing the bucket-wheel dredger performance, productivity, maintenance costs, and reliability, a rational decision was made: to rehabilitate the most essential parts of the dredge, including the bucket wheel and the gearbox. However, the selection and construction of the excavator parts were performed on the ground of available laboratory data for digging resistance. The data itself was determined by the testing methodology that did not include the influence of surrounding water pressure at a certain depth of mining. According to the previous findings, it was necessary to develop a specific research and testing program that would involve appropriate laboratory testing of the geomechanical parameters. These were to represent the influence of hydrostatic water pressure on the working environment—coal. Nevertheless, geomechanical laboratory research tests were initially modified to provide reliable data of cutting resistance, especially in the water under different hydrostatic pressures, fully simulating the “in situ” working conditions of mining, i.e., cutting.

scholarly journals The Influence of Climate and Land-Cover Scenarios on Dam Management Strategies in a High Water Pressure Catchment in Northeast Spain

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1668 ◽  
Author(s):  
J. Zabalza-Martínez ◽  
S. Vicente-Serrano ◽  
J. López-Moreno ◽  
G. Borràs Calvo ◽  
R. Savé ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Management ◽  
Land Cover ◽  
Water Pressure ◽  
Management Strategies ◽  
High Water ◽  
Climate Change Scenarios ◽  
Dam Management ◽  
Dam Inflow ◽  
Similar Decrease

This paper evaluates the response of streamflow in a Mediterranean medium-scaled basin under land-use and climate change scenarios and its plausible implication on the management of Boadella–Darnius reservoir (NE Spain). Land cover and climate change scenarios supposed over the next several decades were used to simulate reservoir inflow using the Regional Hydro-Ecologic Simulation System (RHESsys) and to analyze the future impacts on water management (2021–2050). Results reveal a clear decrease in dam inflow (−34%) since the dam was operational from 1971 to 2013. The simulations obtained with RHESsys show a similar decrease (−31%) from 2021 to 2050. Considering the ecological minimum flow outlined by water authorities and the projected decrease in reservoir’s inflows, different water management strategies are needed to mitigate the effects of the expected climate change.

Effect of Saturation Degree on Concrete Deterioration due to Freeze-Thaw Action

2011 ◽  
Vol 477 ◽  
pp. 404-408 ◽  
Author(s):  
Wen Cui Yang ◽  
Yong Ge ◽  
Bao Sheng Zhang ◽  
Jie Yuan
Keyword(s):  
Frost Resistance ◽  
Water Pressure ◽  
High Water ◽  
Frost Damage ◽  
Critical Value ◽  
Cold Weather ◽  
Saturation Degree ◽  
Freeze Thaw ◽  
Air Content ◽  
The Difference

Freezing-thawing durability of cement concrete is extremely important in cold weather, to better understand mechanism of frost damage and air-entraining，saturation degree of pores in concrete and its relation with frost resistance were studied in this paper. Concrete specimens with different saturation degree from 0 to 100% were prepared used a sealed tin with a high water pressure pump. Then these specimens were subjected to six freezing-thawing cycles and the relative dynamic modulus of elasticity was examined. The results showed that critical saturation degree of concrete with water- binder ratio of 0.30 and 0.47, air content of 1%, 4% and 6% were from 0.60 to 0.80. When its saturation degree exceeded the critical value, concrete was deteriorated significantly after only six freeze-thaw cycles. The critical saturation degree was mainly related to the air content of concrete mixture, and it decreased with the increasing of air content. The difference between the saturation degree and the critical value can be used to evaluate potential frost resistance of concrete, and its result was consistent with the result of frost tests very well.

scholarly journals Structural modifications of lanthanum silicate oxyapatite exposed to high water pressure

2017 ◽  
Vol 37 (5) ◽  
pp. 2149-2158 ◽  
Author(s):  
Aénor Pons ◽  
Emilie Béchade ◽  
Jenny Jouin ◽  
Maggy Colas ◽  
Pierre-Marie Geffroy ◽  
...  
Keyword(s):  
Water Pressure ◽  
High Water ◽  
Structural Modifications ◽  
Lanthanum Silicate ◽  
High Water Pressure

scholarly journals Analisis Numerik Pengaruh Infiltrasi Hujan Terhadap Stabilitas Lereng Di Pangkalan, Sumatera Barat

2020 ◽  
Vol 11 (1) ◽  
pp. 25-36
Author(s):  
Rokhmat Hidayat
Keyword(s):  
Slope Stability ◽  
Hydrological Modeling ◽  
Water Pressure ◽  
Laboratory Data ◽  
Soil Layer ◽  
Infiltration Process ◽  
The Road ◽  
Horizontal Drain ◽  
Landslide Event ◽  
Rain Infiltration

The landslides event was triggered by rain infiltration is an annual occurrence in Indonesia, majority of landslide occur in rainy season. In this research, the case of landslide taken in Pangkalan Area, District of Limapuluh Kota, West Sumatera. The location of the case study is the main access of West Sumatra-Riau, so the landslide in the location is certainly causing close the road. Research phase is geology mapping, geotechnical analysis, and hydrological modeling. Hydrological modeling is done by numerical simulation using laboratory data. The modeling results show that the rain infiltration process resulted in the formation of positive water pressure zone at the foot of the slope, then spread towards the top of the slope.  One day after the rainfall, the soil layer had been saturated. The soil layer will saturate the water, so that the slope stability will decrease and the landslide event will occur. To improve the slope stability, it can be done by preventing water from entering the permeable layer with the installation of the shotcrete layer, and draining the water from the slopes by the installation of horizontal drain.

scholarly journals Finite volume simulation of unsteady water pipe flow

2014 ◽  
Vol 7 (2) ◽  
pp. 83-92 ◽  
Author(s):  
J. Fernández-Pato ◽  
P. García-Navarro
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Finite Volume ◽  
Water Pressure ◽  
Laboratory Data ◽  
Network Models ◽  
Finite Volume Methods ◽  
Analytic Solutions ◽  
Surface Flow ◽  
Pipe Networks

Abstract. The most commonly used hydraulic network models used in the drinking water community exclusively consider fully filled pipes. However, water flow numerical simulation in urban pipe systems may require to model transitions between surface flow and pressurized flow in steady and transient situations. The governing equations for both flow types are different and this must be taken into account in order to get a complete numerical model for solving dynamically transients. In this work, a numerical simulation tool is developed, capable of simulating pipe networks mainly unpressurized, with isolated points of pressurization. For this purpose, the mathematical model is reformulated by means of the Preissmann slot method. This technique provides a reasonable estimation of the water pressure in cases of pressurization. The numerical model is based on the first order Roe's scheme, in the frame of finite volume methods. The novelty of the method is that it is adapted to abrupt transient situations, with subcritical and supercritical flows. The validation has been done by means of several cases with analytic solutions or empirical laboratory data. It has also been applied to some more complex and realistic cases, like junctions or pipe networks.

scholarly journals Combined measurements of Subglacial Water Pressure and Surface Velocity of Findelengletscher, Switzerland: Conclusions about Drainage System and Sliding Mechanism

1986 ◽  
Vol 32 (110) ◽  
pp. 101-119 ◽  
Author(s):  
Almut Iken ◽  
Robert A. Bindschadler
Keyword(s):  
Functional Relationship ◽  
Water Pressure ◽  
Drainage System ◽  
High Water ◽  
Water Levels ◽  
Surface Velocity ◽  
Glacier Surface ◽  
Measured Velocity ◽  
Sliding Mechanism ◽  
Velocity Variations

AbstractDuring the snow-melt season of 1982, basal water pressure was recorded in 11 bore holes communicating with the subglacial drainage system. In most of these holes the water levels were at approximately the same depth (around 70 m below surface). The large variations of water pressure, such as diurnal variations, were usually similar at different locations and in phase. In two instances of exceptionally high water pressure, however, systematic phase shifts were observed; a wave of high pressure travelled down-glacier with a velocity of approximately 100 m/h.The glacier-surface velocity was measured at four lines of stakes several times daily. The velocity variations correlated with variations in subglacial water pressure. The functional relationship of water pressure and velocity suggests that fluctuating bed separation was responsible for the velocity variations. The empirical functional relationship is compared to that of sliding over a perfectly lubricated sinusoidal bed. On the basis of the measured velocity-pressure relationship, this model predicts a reasonable value of bed roughness but too high a sliding velocity and unstable sliding at too low a water pressure. The main reason for this disagreement is probably the neglect of friction from debris in the sliding model.The measured water pressure was considerably higher than that predicted by the theory of steady flow through straight cylindrical channels near the glacier bed. Possible reasons are considered. The very large disagreement between measured and predicted pressure suggests that no straight cylindrical channels may have existed.

Practical Constitutive Model in the Application of Arch Dam Shape Design Calculation

2011 ◽  
Vol 105-107 ◽  
pp. 857-861
Author(s):  
Hong Wang ◽  
Chong Jin ◽  
Xiao Zhou Xia ◽  
Hong Yuan
Keyword(s):  
Constitutive Model ◽  
Mechanical Performance ◽  
Water Pressure ◽  
Safety Margin ◽  
Least Square Method ◽  
High Water ◽  
Arch Dam ◽  
Least Square ◽  
Design Calculation ◽  
High Arch Dam

A fitting curve of stress-strain relation given is applied in numerical analyzing based on Legendre orthogonal polynomial and least square method. The nonlinear constitutive model is employed to examine the shape of an arch dam. For the asymmetries and high water pressure, the safety of High Arch Dam is one of key issues in the design and construction of High Arch Dam. The simulation results show that the basic mechanical performance index is symmetrical distribution. The dam mainly bears pressure and no obvious tensile stress exists in the dam when water level is normal. Material yields in dam heel when 1.4 times overloading is considered. It can be concluded that the dam is reliable and the safety margin is satisfactory.

Sign in / Sign up

Export Citation Format

Share Document