scholarly journals Fatigue Damage at the Root of the Gate Lip of the Water Gate under Variable Water Pressure due to Tide and Ocean Wave

2004 ◽  
Vol 2004 (196) ◽  
pp. 169-179
Author(s):  
Keitaro Konuma ◽  
Masahiro Toyosada ◽  
Koji Gotoh ◽  
Koji Kawai ◽  
Noboru Igarashi
Keyword(s):  
Fatigue Damage ◽  
Water Pressure ◽  
Ocean Wave ◽  
Water Gate ◽  
Variable Water

Fatigue Damage at the Root of the Gate Lip of the Water Gate Under Variable Water Pressure Due to Tide and Ocean Wave

2006 ◽  
Author(s):  
Keitaro Konuma ◽  
Masahiro Toyosada ◽  
Koji Gotoh
Keyword(s):  
Numerical Simulation ◽  
Fatigue Crack ◽  
Water Level ◽  
Crack Growth ◽  
Sea Water ◽  
Water Pressure ◽  
Ground Surface ◽  
Simulation Code ◽  
Water Gate ◽  
Variable Water

The steel water gate, which received variable water pressure due to gap of water level between sea and balancing reservoir, damaged in its gate lip by fatigue crack. In order to find the cause of this damage, various investigate programs, including observation with microscope and measurement of stress and water level, were performed. By the comprehensive analysis of the results of these investigation programs, it was concluded that this damage was caused by the cyclic loading on the gate lip from the ground surface, and found out the relation between sea water level and stress occur at damaged point. After then, the damaged part was replaced with new reinforced element. In addition, for checking the effect of this measure, the crack growth estimation was executed with FLARP, the numerical simulation code which was developed by the authors. As the result of the numerical simulation, the crack growth curve became visible quantitatively, and it was confirmed that the possibility of the reoccurrence of the fatigue crack was removed by the measures which we took, under the assumed loading condition.

scholarly journals WAVE MEASUREMENTS IN OPEN OCEAN

1976 ◽  
Vol 1 (15) ◽  
pp. 6
Author(s):  
Davidson T. Chen ◽  
Benjamin S. Yaplee ◽  
Donald L. Hammond ◽  
Paul Bey
Keyword(s):  
Water Pressure ◽  
Open Ocean ◽  
Ocean Wave ◽  
Naval Research ◽  
Wave Spectra ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Wave Measurements ◽  
Microwave Sensor ◽  
Low Pass

The ability to measure the wave spectra in the open ocean from a moving vessel has met with varying degrees of success. Each sensor to date has suffered in its performance due to environmental conditions or due to its physical placement aboard the vessel for measuring the unperturbed sea. This paper will discuss the utilization of a microwave sensor on a moving vessel for measuring the open ocean wave spectra. Employing microwaves, some of the limitations of other sensors are not experienced. Tucker [1] developed the Tuckermeter for measuring the wave spectra from a moving ship by sensing changes in water pressure due to surface wave conditions. The Tuckermeter is placed below the water line and thus requires calibration for each wave frequency, ship speed, and depth. Since the sensor operates on pressure, it performs as a low pass filter and will not sense the higher frequencies. A microwave shipboard wave height radar sensor for measuring the ocean wave spectra was developed by the Naval Research Laboratory (NRL) and was installed on the S.S. McLean in February 1975 and its performance, design, and analysis of data for one data run will be discussed.

scholarly journals Long-Term Strength of Porous Geomaterials by a Micromechanical Model considering Alternate Wetting and Drying Condition

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jin Zhang ◽  
Shirong Fu ◽  
Tao Ni ◽  
Bei Han ◽  
Chong Shi
Keyword(s):  
Water Pressure ◽  
Micromechanical Model ◽  
Boundary Surface ◽  
Solid Matrix ◽  
Term Strength ◽  
Wetting And Drying ◽  
Alternate Wetting And Drying ◽  
Drying Condition ◽  
Variable Water

This study is devoted to determining the long-term strength of porous geomaterials under alternate wetting and drying condition by statical shakedown analysis. In the framework of micromechanics of porous materials, Gurson’s hollow sphere model with Drucker-Prager solid matrix is adopted as the representative volume element. The effects of alternate wetting and drying are considered as variable water pressure imposed on the inner boundary surface of the unit cell. The cyclic responses are separated as a pure hydrostatic part under compressive/tensive loads and an additional deviatoric part to capture shear effects. The reduction of the long-term strength due to inner water pressure is observed by the illustration of obtained macroscopic criteria with respect to various load parameters. In addition, the accuracy of the analytical solution is also verified by comparing to the results of FEM-based step-by-step computations.

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 Optimization of group borehole drainage of a mine above a high pressure, low permeability aquifer

2020 ◽  
Vol 15 (3) ◽  
pp. 660-672
Author(s):  
Haifeng Lu ◽  
Yuan Zhang ◽  
Manman Zhang ◽  
Guifang Zhang
Keyword(s):  
High Pressure ◽  
Water Pressure ◽  
Control Point ◽  
Mining Area ◽  
Low Permeability ◽  
Level Control ◽  
Effective Measure ◽  
Water Abundance ◽  
Variable Water ◽  
Good Drainage

Abstract Drainage to lower water pressure is an effective measure for preventing and controlling water ingress when mining above a confined aquifer. The deep limestone aquifer in the Huaibei mining area, China, generally has high pressure, low permeability and variable water abundance, so it is difficult to meet single-borehole drainage requirements. In order to achieve good drainage, and take into account engineering and environmental protection requirements, a multi-objective optimization model of group borehole drainage was established. The model takes the minimization of single-hole flow and borehole numbers as the objective functions, and the drawdown in drainage boreholes and the water level control point as the constraint conditions. The particle swarm optimization algorithm was used to solve the model. The results indicate that, for a low permeability aquifer, measures such as using partially penetrating wells, increasing the number of drainage boreholes appropriately and reducing individual borehole yield have good drainage effects. The extent of drilling and amount of drainage are also relatively small. This is all to the good for the drainage. When the optimization results were applied to coal-face drainage in Huaibei the outcome was good.

Fatigue damage property of permeable friction courses under the water-temperature-load coupling action

2021 ◽  
pp. 1-13
Author(s):  
Xingmei Zhang ◽  
Datian Yang ◽  
Guoxiong Wu
Keyword(s):  
Water Temperature ◽  
Fatigue Damage ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Testing System ◽  
Damage Analysis ◽  
Seismic Properties ◽  
Temperature Load ◽  
Fatigue Damage Analysis ◽  
Design Construction

In order to investigate the fatigue damage property of permeable friction courses (PFC) under the coupling action of water, temperature and load, the PFC with length of 2.93 m, width of 1.10 m and thickness of 0.04 m was prepare in the laboratory and tested by the accelerated loading testing system MMLS3. The profilometer and the portable seismic properties analyzer (PSPA) was utilized to measured the rutting depth and modulus of the whole asphalt pavement, respectively. It is found that the PFC is compaction-type rutting. In the position 200 mm, the modulus first increases and then decreases. The excess pore water pressure is not measured in pavement. The results can provide beneficial references for the design, construction and fatigue damage analysis of PFC.

Centrifuge Model Study of SCR Motion in Touchdown Zone

2009 ◽  
Author(s):  
Her Jia Eddie Hu ◽  
Chun Fai Leung ◽  
Yean Khow Chow ◽  
Andrew Clennel Palmer
Keyword(s):  
Fatigue Damage ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Strength ◽  
Load Cycle ◽  
Model Tests ◽  
Stiffness Degradation ◽  
Centrifuge Model ◽  
Cyclic Motion

Steel catenary risers (SCRs) connect seabed pipelines and flow lines to floating structures used for oil and gas production in deep water. Waves and currents induce motions of the structure and the risers. Repeated horizontal and vertical interactions of SCR at the touchdown zone would induce loads on the seabed soil, and would eventually cause fatigue damage to the risers as the number of load cycle increases. The analysis of SCR fatigue damage is heavily dependent on the soil model. Soil behaviour at touchdown zone such as soil remolding, stiffness degradation and deformation of the seabed at the touchdown zone further complicate the accurate assessment of SCR fatigue damage, which is not appropriately quantified in existing design methods. This paper presents model tests simulating the repeated vertical movement of a length of riser on a geotechnical beam centrifuge at the National University of Singapore. During the tests, the pipe was subject to cyclic motion over fixed vertical displacement amplitude from an invert embedment of 0.5 pipe diameter to 3 pipe diameters into the soil. The results from centrifuge model tests show a significant progressive degradation of soil strength and diminution of excess pore water pressure as the number of load cycle increases. The increased soil strength degradation and diminishing excess negative pore water pressure during cyclic motion of the SCR reduce fatigue damage. In view of different types of environment loadings experienced by the floating platform, test results obtained from parametric studies on the effect of cyclic displacement amplitude on soil stiffness degradation will also be presented in this paper. Lastly, a simple upper bound plasticity solution will be presented and compared with the experimental result.

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

Life of the ocean wave

Nature ◽  
2002 ◽  
Author(s):  
Philip Ball
Keyword(s):  
Ocean Wave
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