scholarly journals Determination of permeability of overconsolidated clay from pressuremeter pressure hold tests

2018 ◽  
Vol 55 (4) ◽  
pp. 514-527
Author(s):  
Lang Liu ◽  
David Elwood ◽  
Derek Martin ◽  
Rick Chalaturnyk
Keyword(s):  
Regression Analysis ◽  
Numerical Analysis ◽  
Laboratory Testing ◽  
Constant Pressure ◽  
Creep Effect ◽  
In Situ Conditions ◽  
Sample Recovery ◽  
Horizontal Permeability

A method was developed to interpret the horizontal permeability (kh) from pressuremeter pressure hold tests (PHTs) of approximately 3 min duration. The method relies on a regression analysis of the numerical analysis simulating the consolidation of clay under a constant pressure boundary during undrained expansion. The method was applied to a series of PHTs performed in deep clay formations in the Seattle area. The interpreted permeabilities are thought to be more representative of in situ conditions than those determined by laboratory testing by virtue of reduced disturbance during sample recovery and preparation. Results could be improved with a further exclusion of the creep effect on PHTs.

scholarly journals Experimental determination of thermal conductivity of soil with a thermal response test

2012 ◽  
Vol 16 (4) ◽  
pp. 1117-1126 ◽  
Author(s):  
Milos Banjac ◽  
Maja Todorovic ◽  
Milan Ristanovic ◽  
Radoslav Galic
Keyword(s):  
Thermal Conductivity ◽  
Experimental Determination ◽  
Outer Part ◽  
Thermal Response ◽  
Heating System ◽  
Thermal Response Test ◽  
Response Test ◽  
In Situ Conditions

Optimal design of a borehole heat exchanger, as the outer part of a ground source heat pump heating system, requires information on the thermal properties of the soil. Those data, the effective thermal conductivity of the soil ?eff and the average temperature of the soil T0, enable us to determine the necessary number and depth of boreholes. The determination of thermal conductivity of the soil in laboratory experiments does not usually coincide with the data under in-situ conditions. Therefore, an in-situ method of experimental determination of these parameters, the so-called thermal response test, is presented in this paper. In addition to the description of the experimental procedure and installation overview, the paper describes methods based on theory and presents their basic limitations, through the presentation of experimental data.

scholarly journals The analysis on the correlation parameters of the embankment compaction under in situ conditions

2013 ◽  
Vol 12 (3) ◽  
pp. 097-104
Author(s):  
Maciej Kumor ◽  
Łukasz Kumor ◽  
Joanna Farmas
Keyword(s):  
Particle Size ◽  
In Situ Tests ◽  
Geotechnical Assessment ◽  
In Situ Conditions ◽  
Wide Range ◽  
Correlation Parameters ◽  
And Control

Geotechnical assessment of the implementation correctness of a road embankment wide range of issues, among which important selection and control of the quality of the earthworks are extremely significant. The article presents results of in situ tests determining correlations between the depending parameters defined by a static plate – VSS test – E1 and E2, and obtained from the study LFG Dynamic Load Plate. Studies indicate that the determination of the correlation between the parameters characterizing the particle size distribution (Cc, Cu, D10, D20, D30, D60), and the compaction parameters obtained by examining the compaction of sand embankment (Evd, E1, E2, I0) is physically complex and hence extremely difficult. 

scholarly journals Overconsolidation Ratio Determination of Cohesive Soil

2016 ◽  
Author(s):  
Donatas Urbaitis ◽  
Ieva Lekstutytė ◽  
Domas Gribulis
Keyword(s):  
Seismic Waves ◽  
Field Tests ◽  
Cohesive Soil ◽  
Strength Properties ◽  
Overconsolidation Ratio ◽  
In Situ Conditions ◽  
Ratio Determination ◽  
Penetration Data

In order to evaluate overconsolidation ratio (OCR) of soil, the necessity to restore them as much as possible to in situ conditions appears, because sometimes when it is not taken into account, mistakes could be made while interpreting mechanical – strength properties of the soil. According to the work purpose, overconsolidation ratio of the investigated soil was set by performing odometer test and the obtained values were compared with the OCR calculated from cone and seismic penetration data. When the tests were performed and data analysed, it was found that OCR values depends on soil occurance depth, strength characteristics and stress conditions. The OCR values decreases with the declination of the depth. As many authors noted in the literature – the upper part of the soil is consolidated abnormally, thereby we can see that in our work. When results are evaluate, we can conclude that all of the analysed soils was overconsolidation. That was demonstrated by calculations according static penetration, oedometer test and seismic waves results. OCR values differences between the laboratory and field tests can show low quality of soil sampling, also due to correlations which was applied.

On the Buckley-Leverett Equation With Constant-Pressure Boundary Conditions

SPE Journal ◽  
2016 ◽  
Vol 21 (06) ◽  
pp. 2301-2307 ◽  
Author(s):  
Thormod E. Johansen ◽  
Lesley A. James ◽  
Xiaolong Liu
Keyword(s):  
Analytical Solution ◽  
Flow Rate ◽  
Constant Pressure ◽  
Analytical Determination ◽  
Constant Flow Rate ◽  
Displacement Front ◽  
Constant Rate ◽  
Volumetric Flux

Summary The classical Buckley-Leverett theory applies to 1D linear flow of two immiscible phases under the fundamental assumption that the flow rate (or total volumetric flux) is constant as a function of time. One phase is injected into the medium at a constant rate, thereby displacing the other phase. If the displacing phase is instead injected at constant pressure and the outlet pressure is also constant, the problem is still well-defined; however, the classical Buckley-Leverett theory does not apply. This is because the injected phase and the in-situ phase have different properties such as viscosities. If the boundary pressures are kept constant, the flow rate will, therefore, vary over time. The main result of this paper is to show that the solution of the displacement problem can be obtained from the constant-rate solution through an analytical determination of the flow rate as a function of time, given constant-pressure boundaries. The theory developed in this paper also provides an analytical solution for the location of the displacement front at any given time, the time for frontal breakthrough at the outlet end, and the pressure distribution as a function of time inside the medium. It is demonstrated through computed examples that the constant-flow-rate solution, in general, cannot be used to approximate the corresponding solution for constant-pressure boundaries because the variation in the flow rate is very significant. A standard numerical method has also been applied and compared with the analytical solutions, demonstrating that fine numerical-simulation grids are required for acceptable comparison with the analytical solution.

scholarly journals ENGINEERING GEOLOGICAL CONDITIONS OF THESSALONIKI BASIN FOR UNDERGROUND WORKS

2017 ◽  
Vol 50 (2) ◽  
pp. 760
Author(s):  
A. Kokkala ◽  
V. Marinos
Keyword(s):  
Laboratory Testing ◽  
Field Tests ◽  
Mechanical Parameters ◽  
Geotechnical Data ◽  
In Situ Conditions ◽  
Geological Conditions ◽  
Geological Information ◽  
Geological Situation ◽  
Longitudinal Profiles

The design and construction of underground works in an urban environment, face several geological challenges. The construction of a well-structured database, able to store, manage, analyse and correlate a large amount of geological and geotechnical data, is a powerful tool towards the geological hazard assessment and the geotechnical characterisation of the formations along a tunnel. The data processed by the database are based on borehole geological information, laboratory testing, geotechnical characterisation and in situ field tests, mainly executed in the quaternary and neogene soil formations that are met along the studied area. The processing and assessment of the information, leads to the identification of useful value ranges for several physical and mechanical parameters. The study also focuses in specific areas within the basin of Thessaloniki, highlighting the in situ conditions, by the construction of longitudinal profiles. The purpose of that process, besides incorporating new data, is to provide a tool for turning data into useful information in order to estimate the geological situation and geotechnical behavior of formations in underground works.

In Situ Testing and Analysis of Thermal Properties of the Ground Formation in Jiangsu, China

2014 ◽  
Vol 933 ◽  
pp. 477-481
Author(s):  
Shuai Chen
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Resistance ◽  
Thermal Response ◽  
Geological Structure ◽  
Ground Source ◽  
In Situ Conditions ◽  
Thermal Conductivity Λ

Ground source heat pump (GSHP) systems exchange heat with the ground, often through a closed-loop, vertical, borehole heat exchanger (BHE). The performance of the BHE depends on the thermal properties of the ground formation, as well as soil or backfill in the borehole. The design and economic probability of GSHP systems need the thermal conductivity of geological structure and thermal resistance of BHE. Thermal response test (TRT) method allows the in-situ determination of the thermal conductivity (λ) of the ground formation in the vicinity of a BHE, as well as the effective thermal resistance (Rb) of this latter. Thermal properties measured in laboratory experiments do not comply with data of in-situ conditions. The present article describes the results of thermal properties of the BHE whose depth is 100m in Yancheng City, Jiangsu Province, China. As shown in these results, λ and Rb of borehole are determined as 1.84(W·m-1·K-1) and 0.121 (m·K·W-1) respectively.

scholarly journals Principles of positron porosimetry

Nukleonika ◽  
2015 ◽  
Vol 60 (4) ◽  
pp. 795-800 ◽  
Author(s):  
Radosław Zaleski
Keyword(s):  
Numerical Analysis ◽  
Pore Size ◽  
Pore Volume ◽  
Unique Feature ◽  
Positron Lifetime ◽  
Review Article ◽  
Empirical Parameter ◽  
Positron Annihilation Lifetime

Abstract The paper deals with positron porosimetry (PP), which is based on positron annihilation lifetime spectroscopy (PALS). The numerical analysis of positron lifetime spectra for PP is more demanding than in most of other applications of PALS. The resulting intensity distributions of ortho-positronium (o-Ps) lifetimes are interpreted in terms of the extended Tao-Eldrup (ETE) model, which provides the dependence between the o-Ps lifetime and pore size. Additionally, the relation between the intensity of an o-Ps component and the pore volume allows obtaining pore size distribution (PSD). The value of the empirical parameter Δ, which is dependent on material, can be estimated from the temperature dependence of an o-Ps lifetime. The most unique feature of PP among other techniques that allow determination of PSDs is its ability to perform measurements in almost any conditions. This makes this method suitable for various in situ studies. In this review article, both the capabilities and the limitations of PP are discussed. The methods to overcome some of the limitations are presented.

scholarly journals ANALYSIS OF FACTORS INFLUENCING UPON THE PRECISION OF PREDICTION OF TECHNOLOGICAL PARAMETERS OF THE WEST SIBERIA CENOMANIAN DEPOSITS DEVELOPMENT

2015 ◽  
pp. 68-72
Author(s):  
A. O. Lysov ◽  
S. L. Golofast ◽  
A. V. Krasovskiy
Keyword(s):  
West Siberia ◽  
Production Data ◽  
Quality Level ◽  
Technological Parameters ◽  
Experimental Conditions ◽  
Number Of Factors ◽  
In Situ Conditions ◽  
Reservoir Conditions

This paper describes the errors in determining the permeability and porosity of Cenomanian gas deposits. First of all, the authors emphasize the importance of reproducing the reservoir conditions as close as possible in the process of core analysis. According to the authors, if the experimental conditions do not closely imitate the in-situ conditions, then the applicable conversation factors or functions should be used. Using this approach in constructing the petrophysical relation-ships and at other stages of reserves estimation will reduce the uncertainty in determination of the gas reserves value. It is also noticed in the article that a number of factors forming the value of error in reservoir parameters in the areas of wells is inevitable. To improve the quality level of the development design it is necessary to take into account a degree of reliability of initial geological and production data.

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