Upward movement of fines in sand under one-dimensional water pressure change

2017 ◽  
pp. 415-419
Author(s):  
Takashi Tsuchida ◽  
Suguru Yoshimuta ◽  
Ryoichi Asa-umi
Keyword(s):  
Water Pressure ◽  
Pressure Change ◽  
Upward Movement ◽  
One Dimensional

scholarly journals Influence of pore water pressure change on consolidation behavior of saturated poroelastic medium

2020 ◽  
Vol 382 ◽  
pp. 375-379
Author(s):  
Chao-Lung Yeh ◽  
Wei-Cheng Lo ◽  
Cheng-Wei Lin ◽  
Chung-Feng Ding
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Saturated Porous Medium ◽  
Water Pressure ◽  
Soil Layer ◽  
Pressure Change ◽  
Clay Layer ◽  
Poroelastic Medium ◽  
Total Settlement ◽  
Consolidation Behavior

Abstract. There are many factors causing land subsidence, and groundwater extraction is one of the most important causes of subsidence. A set of coupled partial differential equations are derived in this study by using the poro-elasticity theory and linear stress-strain constitutive relation to describe the one-dimensional consolidation in a saturated porous medium subjected to pore water pressure change due to groundwater table depression. Simultaneously, the closed-form analytical solutions for excess pore water pressure and total settlement are obtained. To illustrate the consolidation behavior of the poroelastic medium, the saturated layer of clay sandwiched between two sand layers is simulated, and the dimensionless pore water pressure changes with depths and the dimensionless total settlement as function of time in the clay layer are examined. The results show that the greater the water level change in the upper and lower sand layers, the greater the pore water pressure change and the total settlement of the clay layer, and the more time it takes to reach the steady state. If the amount of groundwater replenishment is increased, the soil layer will rebound.

One-dimensional consolidation of multilayered aquifer systems with viscoelastic properties induced by time-dependent groundwater drawdown

2021 ◽  
pp. qjegh2021-073
Author(s):  
Weitao Yang ◽  
Jin Xu
Keyword(s):  
Viscoelastic Properties ◽  
Numerical Solutions ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Time Dependent ◽  
Analytical Models ◽  
Consolidation Process ◽  
One Dimensional ◽  
Groundwater Drawdown ◽  
Aquifer Systems

Most analytical and semi-analytical models for pumping-induced land subsidence invoke the simplifying assumptions regarding characteristics of geomaterials, as well as the pattern of drawdown response to pumping. This paper presents an analytical solution for one-dimensional consolidation of the multilayered soil due to groundwater drawdown, in which viscoelastic property and time-dependent drawdown are taken into account. The presented solution is developed by using the boundary transformation techniques. The validity of the proposed solution is verified by comparing with a degenerated case for a single layer, as well as with the numerical solutions and experimental results for a two-layer system. The difference between the average consolidation degree Up defined by hydraulic head and that Us defined by total settlement is discussed. The detailed parametric studies are conducted to reveal the effects of viscoelastic properties and drawdown patterns on the consolidation process. It is revealed that while the effect of different drawdown response patterns is significant during the early-intermediate stages of consolidation, the viscoelastic properties may have a more dominant influence on long-term consolidation behavior, depending on the values of the material parameters, which are reflected in both the deformation process of soil layers and the dissipation of excess pore-water pressure.

scholarly journals The Uplift of Unteraargletscher at the Beginning of the Melt Season—A Consequence of Water Storage at the Bed?

1983 ◽  
Vol 29 (101) ◽  
pp. 28-47 ◽  
Author(s):  
A. Iken ◽  
H. Röthlisberger ◽  
A. Flotron ◽  
W. Haeberli
Keyword(s):  
Water Pressure ◽  
Storage System ◽  
Water Storage ◽  
High Water ◽  
Early Summer ◽  
Upward Movement ◽  
Drainage Channels ◽  
Summer Maximum ◽  
Cavity Development ◽  
The Times

Abstract Results of systematic movement studies carried out by means of an automatic camera on Unteraargletscher since 1969 are discussed together with supplementary theodolite measurements made at shorter intervals and over a longer section of the glacier. In addition to the typical spring/early summer maximum of velocity known from other glaciers, an upward movement of up to 0.6 m has been recorded at the beginning of the melt season. It was followed, after a few fluctuations of the vertical velocity, by an equal but slower downward movement which continued at an almost constant rate for about three months. Possible explanations of the uplift are discussed, the most satisfactory explanation being water storage at the bed. The observations then suggest that this storage system is efficiently connected with the main subglacial drainage channels only during times of very high water pressure in the channels. Detailed measurements showed that the times of maximum horizontal velocity coincided with the times of maximum upward velocity rather than with the times when the elevation of the surveyed poles had reached a maximum. On the basis of the hypothesis of water storage at the bed this finding means that the sliding velocity is influenced mainly by the subglacial water pressure and the actual, transient stage of cavity development, while the amount of stored water is of lesser influence.

Vacuum and surcharge combined one-dimensional consolidation of clay soils

2002 ◽  
Vol 39 (5) ◽  
pp. 1126-1138 ◽  
Author(s):  
E Mohamedelhassan ◽  
J Q Shang
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Clay Soils ◽  
Soil Consolidation ◽  
Excess Pore Water Pressure ◽  
One Dimensional ◽  
Consolidation Model ◽  
The One ◽  
Excess Pore

In this study, a vacuum and surcharge combined one-dimensional consolidation model is developed. Terzaghi's consolidation theory is revisited by applying the initial and boundary conditions corresponding to combined vacuum and surcharge loading on a soil. A test apparatus is designed, manufactured, and assembled to verify the model. The apparatus has the capacity of applying designated vacuum and surcharge pressures to a soil specimen, and it allows for the measurement of the excess pore-water pressure, settlement, and volume change during the consolidation process. Two series of tests are performed using the apparatus on two reconstituted natural clay soils, namely, the Welland sediment at water contents close to its liquid limit and the Orleans clay, reconstituted and consolidated under an effective stress of 60 kPa. The former test series mimics the strengthening of a very soft soil, such as the hydraulic fill used in land reclamation. The latter test series is designed to study vacuum–surcharge combined strengthening of a consolidated soil. It is demonstrated from the experiments that the one-dimensional vacuum-surcharge consolidation model describes the consolidation behaviour of both soils well. The consolidation characteristics of the soils show no discrimination against the nature of the consolidation pressure, namely, whether they are consolidated under the vacuum pressure alone, under the surcharge pressure alone, or under a pressure generated by the combined application of vacuum and surcharge. The study concluded that the soil consolidation characteristics obtained from the conventional consolidation tests can be used in the design of vacuum preloading systems, provided that the one-dimensional loading condition prevails.Key words: consolidation, soil improvement, vacuum pressure, surcharge pressure, excess pore-water pressure, soil consolidation parameters.

Steady Compressible Flow through a Single Row of Radial Holes in the Wall of a Pipeline

1970 ◽  
Vol 12 (4) ◽  
pp. 248-258 ◽  
Author(s):  
G. H. Trengrouse
Keyword(s):  
Discharge Coefficient ◽  
Pressure Change ◽  
Single Row ◽  
One Dimensional ◽  
Discharge Coefficients ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Flow Through ◽  
Flow Theories ◽  
Good Agreement

Measured values of discharge coefficient for air flow through a single row of radial holes in the wall of a pipeline are reported, together with the values of pipe Mach numbers in the immediate vicinity of the holes. A wide range of pressure and area ratios are considered, the flow through the holes being either into or out of the pipe. It is shown that the effects on the measured values of both the pressure level at discharge from the holes and the air temperature are negligible. The agreement between the pressure change in the pipeline due to the holes, obtained experimentally, and that predicted by simple, one-dimensional flow theories is generally unsatisfactory. However, theoretical predictions of the jet efflux angles based on two-dimensional, incompressible, non-viscous flow arguments are in good agreement with those measured, but discrepancies do arise in the prediction of discharge coefficients.

Cutting Force Dynamics as a Tool for Surface Profile Monitoring in AWJ

1995 ◽  
Vol 117 (3) ◽  
pp. 340-350 ◽  
Author(s):  
R. Kovacevic ◽  
R. Mohan ◽  
Y. M. Zhang
Keyword(s):  
Normal Force ◽  
Moving Average ◽  
Water Pressure ◽  
Model Identification ◽  
Surface Profile ◽  
Pressure Change ◽  
Traverse Speed ◽  
Abrasive Waterjet ◽  
Dynamic Force ◽  
Distance Method

Abrasive waterjet cut surface is characterized using static and dynamic characterization techniques. A novel method of auto regressive moving average model identification called model distance method is utilized here for surface profile and dynamic force characterization. More information about the surface profile generating mechanism is derived through wavelength decomposition of the ARMA models. The dynamic workpiece normal force in abrasive waterjet is influenced by process parameters such as fluctuations in water pressure, change in abrasive flow rate, vibration of the positioning system, traverse speed, nozzle diameter, etc. An attempt has been made in this paper to link the dynamics of the process to the quality of the generated surface. The feasibility of using the dynamic workpiece normal force as a parameter for on-line monitoring of the surface profile generated by abrasive waterjet is also investigated.

Simplified Computation of 1D Consolidation for Unsaturated Soil when Air Phase Neglected

2010 ◽  
Vol 168-170 ◽  
pp. 298-302
Author(s):  
Hao Feng Xu ◽  
Kang he Xie
Keyword(s):  
Unsaturated Soils ◽  
Laboratory Tests ◽  
Continuity Equation ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Mass ◽  
Excess Pore Water Pressure ◽  
One Dimensional ◽  
Consolidation Model ◽  
Consolidation Analysis

It is a complicated problem for consolidation analysis of unsaturated soils. Nowadays’ theories are very theoretical, and the parameters in them are so many that it is difficult to solve the equations, i.e., they are not excellently fit for application in engineering. So it is significant to get a simplified theory for consolidation analysis of unsaturated soils. In this paper, according to the phenomena observed in consolidation’s experiments for unsaturated soils, it is assumed that pore-air pressure undergoes an instantaneous dissipation and the consolidation of unsaturated soils can be described as the process of dissipation of excess pore-water pressure. Then a simplified consolidation model is put forward. And based on the principle of the whole soil mass conversation, the continuity equation is founded. Subsequently one- dimensional consolidation equation is derived, which is similar to Terzaghi’s equation for consolidation of saturated soils. Finally, the numerical results from the derived equation are compared with the experimental results from laboratory tests reported in the literature, and the agreement is good. It can be concluded that the hypothesis is rational and the simplified computation is practical in engineering.

ENGINEERING MODEL FOR THE CONSOLIDATION OF OIL SEED MATERIAL DURING VISCOPLASTIC DEFORMATION

2020 ◽  
Author(s):  
А.В. Гукасян ◽  
Д.А. Шилько
Keyword(s):  
Equations Of State ◽  
Liquid Mixture ◽  
Pressure Change ◽  
Viscoplastic Deformation ◽  
Displacement Gradient ◽  
One Dimensional ◽  
Velocity Gradients ◽  
Calculation Process ◽  
Dimensional Version ◽  
Solid Liquid

Cоставлено модельное уравнение консолидации масличного материала, учитывающее процесс его вязкопластичной деформации для неньютоновской твердожидкой смеси. Использованы параллельные соединения моделей Ньютона с вязкостью ηН и Сен-Венана с пределом текучести σ0. Обе формулы представлены в виде конститутивных реологических уравнений состояния. В процессе расчета использовано прямое и обратное преобразования Лапласа. Рассмотрен одномерный вариант пластической деформации масличного материала. Выведены градиенты смещения и скорости. Полученное уравнение распределения давления по высоте слоя материала позволяет определить изменение давления по толщине прессуемого материала с учетом его вязкопластичной деформации. The aim of the study was to compile a model equation for the consolidation of oilseeds, taking into account the process of its viscoplastic deformation for a non-Newtonian solid/liquid mixture. To compile the equation, we used in parallel a combination of Newton models with viscosity ηН and Saint-Venant with yield strength σ0. Both formulas are constitutive rheological equations of state. In the calculation process, the direct and inverse Laplace transforms were used, and a one-dimensional version of the plastic deformation of the oil material was considered, due to which the displacement gradient and velocity gradients were derived. As a result, the obtained equation of pressure distribution over the height of the material layer allows one to determine the pressure change over the thickness of the pressed material, taking into account its viscoplastic deformation.

Analysis of One-Dimensional Consolidation of Non-Homogeneous Layer with Exponential Flow Law

2014 ◽  
Vol 638-640 ◽  
pp. 374-379 ◽  
Author(s):  
Feng Xi Zhou ◽  
Yi Ming He ◽  
Ying Xin
Keyword(s):  
Numerical Solution ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Decisive Role ◽  
Homogeneous Layer ◽  
One Dimensional ◽  
Governing Differential Equation ◽  
Degree Of Consolidation ◽  
Flow Law ◽  
The One

Based on exponential flow law, the analytical solution to the one-dimension consolidation governing differential equation was deduced when the laws of permeability and compressibility coefficients with depth can be expressed as exponential function. By finite difference method, the numerical solution of excess pore water pressure and degree of consolidation was obtained, then the reliability of numerical solution is verified by comparing numerical results with analytical results, and consolidation behavior of non-homogeneous layer with exponential flow law under various parameters is analyzed. The results showed that under the condition of the two-sided drainage, the heterogeneity of foundation consolidation of index of seepage speed depends on the index of the size and the size of the non-uniform parameters. That is when the index m is bigger, increase the permeability coefficient, reduce the compression coefficient, the consolidation is faster, but the inhomogeneous parameters are still play a decisive role.

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