Thaw–Consolidation Tests on Undisturbed Fine-grained Permafrost

1974 ◽  
Vol 11 (1) ◽  
pp. 202-214 ◽  
Author(s):  
J. F. Nixon ◽  
N. R. Morgenstern
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Surface Temperature ◽  
Pore Water ◽  
Excellent Agreement ◽  
Test Results ◽  
Fine Grained ◽  
Arctic Soils ◽  
Thaw Consolidation ◽  
Pore Water Pressures

A series of thaw–consolidation tests on undisturbed frozen samples of Arctic soils is described. The tests were carried out in a special oedometer, and thawing was induced by the application of a sudden constant increase in surface temperature. Settlements, pore water pressures, and rates of thaw are measured, and interpreted in the light of current theories of heat transfer and thaw–consolidation. Excellent agreement is obtained between predicted and observed thaw rates, using published thermal properties. The observed pore pressures and settlements also are consistent with predicted behavior.These test results on a variety of undisturbed permafrost samples increase the level of confidence when applying the theory of consolidation for thawing soils to natural permafrost deposits.

Thermal Aspects of Grinding: The Effect of the Wheel Bond on Heat Transfer to an Abrasive Grain

1991 ◽  
Vol 113 (4) ◽  
pp. 395-401 ◽  
Author(s):  
M. W. Harris ◽  
A. S. Lavine
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Heat Conduction ◽  
Beneficial Effect ◽  
Surface Temperature ◽  
Thermal Damage ◽  
High Thermal Conductivity ◽  
Abrasive Grain ◽  
Grain Surface

Heat generated during grinding can cause thermal damage to the workpiece and wheel. It is therefore important to understand the thermal aspects of grinding. This paper addresses heat conduction into the wheel, by considering a single abrasive grain in contact with the workpiece. In particular, the effect of the bond material on conduction into the grain is investigated. The results for the grain surface temperature are given in terms of parameters describing the geometry and thermal properties of the grain and bond. The beneficial effect of a high thermal conductivity for both the grain and the bond is clearly demonstrated.

Physical and numerical modelling of drainage and consolidation of tailings near a vertical waste rock inclusion

2020 ◽  
Author(s):  
Faustin Saleh-Mbemba ◽  
Michel Aubertin
Keyword(s):  
Pore Water ◽  
Fine Particles ◽  
Numerical Models ◽  
Physical Modelling ◽  
Waste Rock ◽  
Coupled Processes ◽  
Water Drainage ◽  
Fine Grained ◽  
Pore Water Pressures ◽  
Tailings Impoundments

The use of waste rock inclusions in tailings impoundments is a recent technique that offers many advantages, but it also raises a few technical issues that must be addressed to optimize their design. A laboratory physical modelling study was conducted to assess the effect of waste rock inclusion on the behavior of initially saturated tailings in terms of drainage and consolidation. The evolution of pore water pressures and settlements after hydraulic deposition of the fine-grained tailings (slurry), with and without a drainage inclusion, has been monitored and analyzed. This investigation also focused on the evolution of the tailings void ratio and volumetric water content, the amount of water transferred to the waste rock, and the movement of fine particles at the interface between the two materials. The experimental results are used to demonstrate how such waste rock inclusion can affect tailings consolidation by reducing pore water pressures with accelerated water drainage, for various imposed conditions. The experimental data are also analysed with numerical models to better understand the coupled processes involved. A discussion follows on practical implications of the use of waste rock inclusions in tailings impoundments.

scholarly journals Cylindrical Piezometer Responses in a Humified Fen Peat

1994 ◽  
Vol 25 (3) ◽  
pp. 167-182 ◽  
Author(s):  
Andrew J. Baird ◽  
Simon W. Gaffney
Keyword(s):  
Hydraulic Conductivity ◽  
Response Time ◽  
Pore Water ◽  
Test Data ◽  
Test Results ◽  
Recovery Test ◽  
Pore Water Pressures ◽  
Compressible Soil ◽  
Time Theory

Most studies of peat hydrology have concentrated on processes below the watertable where pore water pressures and hydraulic conductivity are measured using piezometers. While piezometer head recovery tests in poorly humified bog peats give responses similar to those expected from rigid soils, a number of studies have suggested that matrix compressibility might be important in affecting head recovery test results in well humified bog peats. Until now no data have been available for humified fen peats. We apply the response time theory of Brand and Premchitt (1982) for compressible soils, and Hvorslev (1951) for rigid soils, to head recovery test data obtained from open cylindrical piezometers installed in a humified fen peat in Somerset, England. To the best of our knowledge this is also the first quantitative application of compressible soil theory for piezometers to any peat. Our results show that compression and swelling of the peat matrix do affect the course of head recovery in the piezometers used in the study. We comment on the significance of this finding for the calculation of hydraulic conductivities and pore water pressures in this peat type.

Thaw–Consolidation of Some Layered Systems

1973 ◽  
Vol 10 (4) ◽  
pp. 617-631 ◽  
Author(s):  
John F. Nixon
Keyword(s):  
Predictive Power ◽  
Considerable Time ◽  
Layered Systems ◽  
Fine Grained ◽  
Arctic Soils ◽  
Thaw Consolidation ◽  
Fine Grained Soil ◽  
The Stability ◽  
Excess Pore Pressures ◽  
Excess Pore

In order to assess the stability and deformation qualities of thawing arctic soils, a theory of thaw–consolidation must be established to predict the dissipation of excess pore fluids. The predictive power of current mathematical models is considerably enhanced by consideration of some common departures from homogeneity. In the first instance a permafrost profile of two different soil types is analyzed numerically, each layer having different thermal and geotechnical properties. The presence of a surficial layer, although minor in extent, may influence for a considerable time the behavior of the underlying layer. Secondly, the excess pore pressures in a fine-grained soil overlying an ice layer are treated theoretically, and the results suggest that foundation conditions over a thawing ice layer may not be as critical as sometimes is supposed.

Pore-Water Pressures in Freezing and Thawing Fine-Grained Soils

1996 ◽  
Vol 10 (2) ◽  
pp. 77-92 ◽  
Author(s):  
K. Dieter Eigenbrod ◽  
Sven Knutsson ◽  
Daichao Sheng
Keyword(s):  
Pore Water ◽  
Freezing And Thawing ◽  
Fine Grained ◽  
Pore Water Pressures

Conduction of heat in a solid with a power law of heat transfer at its surface

1950 ◽  
Vol 46 (4) ◽  
pp. 634-641 ◽  
Author(s):  
J. C. Jaeger
Keyword(s):  
Heat Transfer ◽  
Differential Equation ◽  
Thermal Properties ◽  
Boundary Conditions ◽  
Surface Temperature ◽  
Linear Theory ◽  
Power Law ◽  
The Body ◽  
Reasonable Accuracy ◽  
Technical Problems

In many technical problems on conduction of heat involving convection, radiation, or evaporation at the surface of a body, the flux of heat at the surface is known empirically as a function of the surface temperature with reasonable accuracy. The thermal properties of the body also vary with the temperature, but in many cases the nature of this variation is completely unknown, and in others it is slight over the range of temperature involved. Thus it seems worth while studying problems on conduction of heat in a medium with constant thermal properties and with heat transfer at its surface a given function of the surface temperature. Mathematically such problems occupy an interesting position between the classical linear theory and the general case in which both the differential equation and the boundary conditions are non-linear.

scholarly journals Pore pressures induced by piezocone penetration

2016 ◽  
Vol 53 (3) ◽  
pp. 540-550 ◽  
Author(s):  
Jin-chun Chai ◽  
Md. Julfikar Hossain ◽  
Da-Jun Yuan ◽  
Shui-long Shen ◽  
John P. Carter
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Initial Distribution ◽  
Laboratory Model ◽  
Two Dimensional ◽  
Test Results ◽  
Cone Penetration ◽  
Coefficient Of Consolidation ◽  
Pore Water Pressures

The excess pore-water pressures (u) induced by piezocone penetration and their dissipation around the cone have been investigated by laboratory model tests and theoretical–numerical analyses. Based on the test results, a method for predicting cone penetration–induced distribution of u has been proposed. By numerical analysis using the predicted initial distribution of u it has been demonstrated that dissipation of the pore-water pressure measured at the shoulder of the cone (u2-type cone) is a two-dimensional (horizontal radial and vertical) process. A back-fitted coefficient of consolidation in the horizontal direction (ch) can be obtained by comparing the simulated and laboratory-measured two-dimensional dissipation curves. It has also been shown that a published method for estimating ch from measured nonstandard dissipation curves (in which u2 increases initially and then decreases) results in values of ch that agree well with values of ch deduced from the two-dimensional analysis.

Effect of soil suction on slope stability at Notch Hill

1989 ◽  
Vol 26 (2) ◽  
pp. 269-278 ◽  
Author(s):  
J. Krahn ◽  
D. G. Fredlund ◽  
M. J. Klassen
Keyword(s):  
Slope Stability ◽  
Pore Water ◽  
Friction Angle ◽  
Soil Suction ◽  
Test Results ◽  
Surface Slope ◽  
Near Surface ◽  
Frictional Strength ◽  
Pore Water Pressures ◽  
Flat Ground

The side slopes of a railway embankment in central British Columbia, constructed with local lacustrine silt, on relatively flat ground, began to fail several years after construction. Shallow instability ultimately developed on both sides of the embankment over a distance of several kilometres. Initially, the soil had a significant apparent cohesive strength. With time, the strength appeared to diminish owing to the dissipation of negative pore-water pressures. The remaining frictional strength was not sufficient to maintain stability, since the slopes were constructed at angles close to the peak effective friction angle of the soil. This case history, together with the laboratory saturated and unsaturated strength test results and field suction measurements, demonstrates the dramatic effect of negative pore-water pressures on near-surface slope stability. Key words: soil suction, slope stability, nonsaturated soils, shear resistance, tensiometers.

Pulsed Thermal Imaging Measurement of Thermal Properties for Thermal Barrier Coatings Based on a Multilayer Heat Transfer Model

2014 ◽  
Vol 136 (8) ◽  
Author(s):  
J. G. Sun
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Surface Temperature ◽  
Thermal Barrier Coatings ◽  
Thermal Imaging ◽  
Temperature Response ◽  
Heat Transfer Model ◽  
Thermal Barrier ◽  
Transfer Model ◽  
Barrier Coatings

Thermal properties of thermal barrier coatings (TBCs) are important parameters for the safe and efficient operation of advanced turbine engines. This paper presents a new method, the pulsed thermal imaging–multilayer analysis (PTI–MLA) method, which can measure the coating thermal conductivity and heat capacity distributions over an entire engine component surface. This method utilizes a multilayer heat transfer model to analyze the surface temperature response acquired from a one-sided pulsed thermal imaging experiment. It was identified that several experimental system parameters and TBC material parameters may affect the coating surface temperature response. All of these parameters were evaluated and incorporated as necessary into the formulations. The PTI–MLA method was demonstrated by analyzing three TBC samples, and the experimental results were compared with those obtained from other methods.

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