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Sunday, November 15, 2020 | History

2 edition of Strength and deformation tests on frozen peat found in the catalog.

Strength and deformation tests on frozen peat

Ivan C. MacFarlane

Strength and deformation tests on frozen peat

  • 267 Want to read
  • 28 Currently reading

Published by National Research Council of Canada in Ottawa .
Written in English

  • Frozen ground -- Testing.,
  • Peat -- Testing.

  • Edition Notes

    Statementby I.C. MacFarlane.
    SeriesResearch paper of the Division of Building Research, no. 433
    LC ClassificationsTA713 .M28
    The Physical Object
    Pagination143-149 p.
    Number of Pages149
    ID Numbers
    Open LibraryOL5387327M
    LC Control Number72562360

      The test results showed that frozen silt presents strain softening in shear process under low confining pressures, but strain softening phenomenon decreases with increase of confining pressures. In order to reproduce the instaneous deformation behavior of frozen silt, a disturbed state constitutive model is developed and verified. Advanced Laboratory Stress-Strain and Strength Testing of Geomaterials in Geotechnical Engineering Practice Behavior of Granular Materials Pallara, O., Froio, F., Rinolfi, A., and Lo Presti, D. Assessment of Strength and Deformation of Coarse Grained Soils by Means of Penetration Tests and Laboratory Tests on Undisturbed Samples Umetsu, K. Solid is one of the four fundamental states of matter (the others being liquid, gas and plasma).The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural rigidity and resistance to a force applied to the surface. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it.   Compared with unfrozen soils, the strength and deformation characteristics of frozen soils are more complex owing to the existence of ice, so these strength criteria are unreasonable for frozen soils. A series of studies [] on the strength and deformation characteristics of frozen soils were carried out.

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Strength and deformation tests on frozen peat by Ivan C. MacFarlane Download PDF EPUB FB2

Strength and deformation tests on frozen peat. By I. MacFarlane. Abstract. Very little information is available on the properties of peat in its frozen state. This is considerably more information on the compressive strength and physical properties of ice and of frozen soils in general.

Russian studies have shown that the stress-deformation Author: I. MacFarlane. It has been approximately 80 years since the first effective stress strength testing of peat was performed using triaxial apparatus.

In light of recent unexpected failures of embankments, dykes, foundations and slopes in peat deposits, it is timely to review current laboratory practice and also provoke discussion about the best way forward for understanding and determining the effective stress Cited by: The results of static creep tests and repeated loading compression tests on samples of frozen clayey silt, peat, and sand obtained from Cornwallis Island, Northwest Territories, Canada, are reported and compared.

Special oversized end platens were used to reduce end effects on the cylindrical test. Aiming at the problems of disease and adverse geological section of peat soil, the entity test project, the settlement deformation law of peat soil roadbed is analyzed, and the theoretical calculation results and the actual monitoring results of test section compares the total longitudinal settlement.

Due to changes in layer thickness, as peat soil, Author: Yumin Han, Xiaoxing Shi. McGraw-Hill Book Company, New York: – Strength and deformation tests on frozen peat.

where P is the maximum load and C is a constant depending on the strength of the frozen. The shear strength behaviour of peat soil are performed by testing three samples of original peat soil with different moisture content.

The one-dimensional consolidation test and the direct shear test by using small shear box was used in this study. Isotropically consolidated undrained (CIU) triaxial tests were carried out, and a new method of evaluating the shear strength of peat was implemented.

Numerical modeling that used the measured mechanical, hydraulic, and thermal properties simulated reasonably well the performance of road embankments constructed on seasonally frozen peat. A series of triaxial shear, creep and relaxation tests with different stress paths were conducted on frozen loess at a temperature of −6 °C in order to experimentally study the path-dependent strength and deformation behaviours of the loess.

In general, an excavated foundation places the surrounding soil in a state of unloading. By simulating the consolidating and freezing processes of a foundation and then carrying out shear tests under loading and unloading, this project compared changes of yield strength and failure strain under two stress paths and analyzed reasons for the frozen wall failure.

General Peat is a living mass and many factors affect its performance. The consolidation and settlement due to new and existing roads can usually be predicted but other effects, e.g.

adjacent drainage work, an unusual dry summer, a change in the water table in the peat, etc can also occur over which the engineer Continue reading 2. Behaviour of peat →. Construction of road embankments or other infrastructures on soft peat is a challenge. The main problems are high compressibility and rather low undrained shear strength of peat.

Mass stabilization provides a solution to improve the properties of a peaty subgrade. Mass stabilization is a ground improvement method, where hardened soil mass is created by adding binder into soil and by. A series of triaxial shear, creep, and stress relaxation tests were performed at a temperature of −6 °C in order to investigate the strength and deformation behaviours of frozen loess under different stress paths.

PDF | On Jun 1,Matthew J. Baldwin published Book review: Manual of Soil Laboratory Testing. Volume II: Permeability, Shear Strength and Compressibility Tests | Find, read and cite all the.

The last release of PEAT was June 2, Note: On December 1,FSBPT made available to schools an academic version of PEAT at the PT and PTA levels. Academic PEAT contains different exams than the PEAT available for individuals.

PEAT is an online product only. When you purchase PEAT you will have sixty days access to the online product. After the freeze-thaw tests, the frozen samples were removed at − 20 °C (limit ambient temperature) to experiment on the shear strength. The axial loading was 15 kg, and the strength test should be conducted for at least six times on the same soil sample.

Instantaneous strength and long-term strength. Vane strength profiles were obtained in a 7 m thick deposit consisting of sphagnum peat (0–4 m), sphagnum carex peat (4–6 m), and carex sphagnum peat (6–7 m). Vane tests were also carried out in the sphagnum peat under anchored Plexiglas sheets to observe the mode of deformation and failure and to measure the movement of markers inserted.

Attraction is defined as cohesion, c, divided by tan0': Table 1Typical values of attraction (a) and friction (tanθ') Effective stress shear strength parameters a, kPa tan^' Silt, soft Silt, medium Silt, stiff Undrained shear strength (s,) The cone factor, NK X = (qt -a^l% was. Peat Strength [17] At the end of the study period, we measured peat strength at each of the 18 subsites using a penetrometer.

The penetrometer was made of a m long, 10 mm diameter iron rod and covered with electrical tape to make it slide easier in the peat. In the past it was found that the isotropic time-dependent Soft Soil Creep model could be successfully used to determine deformation and strength of embankments on peat, and an elaborate procedure.

Uniaxial unconfined compression tests were carried out on frozen saturated Ottawa sand containing about 20% by weight of water, at temperatures between −2 and − 15°C, and at strain rates varying between 10 −7 and 10 −2 s − compressive strength and the initial tangent modulus increased with increasing strain rate and with decreasing temperature.

Former tests on non-cohesive frozen soil material, performed at CDM's frozen soils lab in Bochum, Germany, indicated a major impact on the frozen strength and deformation behavior at a salt concentration of S = %, whereas other tests on soil samples with a higher content of fines and nearly the same salinity showed a minor impact of the.

The horizontal stiffness of Shelby specimens was found to be to times their vertical stiffness. The shear strength of intact peat is made up of interparticle friction as well as tension in the peat fibres.

A novel procedure for estimating the interparticle frictional strength of fibrous peat from CU triaxial test results is proposed. Water saturated materials exhibit a zone of partially frozen soil at the frozen-unfrozen soil interface.

To define the critical failure surface and governing shear strength in this zone, the effects of partial freezing on the mechanical behaviour as a freezing front advances, must be well understood.

This paper presents the results of a study carried out into the behavior of an Irish peat when stabilized with different binders. Performance of different binders is discussed. Particular attention is given to the understanding of the behavior of stabilized peat with regards to the engineering properties (deformation and shear strength.

Determination of Strength parameters The shear strength parameters cohesion (c) and friction angle (Φ) can be determined by different laboratory tests for different types of soils. Direct shear test: The soil sample is tested in a confined metal box of square cross-section.

The box has two halves horizontally and a small clearance is. The results of the evaluation of shear strength and deformation parameters of organic subsoil by in situ tests were also interpreted.

The results of the investigations confirmed the necessity to use different correction factors for estimation of constrained modulus from CPTU and DMT tests. The seasonally frozen ground has been focused on as research topics such as the frost heaving under the asphalt road rather than the permafrost ground due to the latitudinal location of Korea.

However, the recent construction of the second Korean Antarctic research station, the Jangbogo station and the participation on the development of the natural gas pipeline in Russia arouse the research.

A large direct simple shear device has been developed for the testing of peat at low normal stress. The large size allows adequate representation of the often coarse structure of peat, increases the accuracy with which small loads can be applied and diminishes device resistances to acceptably small proportions.

The deformation process is the coupling of volume variation of organic matter, gas bubbles and water drainage. The proposed model is used to simulate a series of peat laboratory oedometer tests, and the model can well capture the test results with reasonable model parameters.

Effects of model parameters on deformation of peat are also analyzed. The strength increases with preloading and decrease in moisture content. Rule of thumb if you don't know the strength well is to fill in stages of 6 feet with about a month between stages and be sure to not disturb the upper mat.

In the zone beneath the mat you can use a vane to determine the shear strength of the peat. Therefore, the design and maintenance of these engineering projects require a developed understanding of the strength and deformation characteristics of frozen soils under different stress paths.

Direct-tension tests (Rowe et al., ) and tension box apparatus (e.g. see Figure 20) allow investigation of the tensile strength of fibrous peat. Beam tests (Helenelund, ) also allow investigations of its flexural strength and deformability.

However, the focus of this discussion is tension box devices, which consist of two half-boxes. However, a strong correlation was found between normalized V s (by water content, w) and s u (derived from direct simple shear tests).

A single operator can collect a continuous profile of V s and w simultaneously and therefore derive a one-dimensional (1D) s u profile for the full peat thickness. Some limitations in the use of the derived.

11 hours ago  Shear Strength of Soil zUnconfined compression test zTriaxial test zCompression zExtension Unconfined Compression Test Soil Specimen.

01 g 1 x Electronic top pan balance x 1 g 1 x Aluminium Scoop, large. 5% compared with seawater alone at the 90 th day., unit weight, water content at failure, porosity, degree of saturation, and soil pH. Review of peat strength, peat characterisation 71 limitations of the vane test and reports that the test tends to overestimate the shear strength of peat.

However he suggested that it remains a useful simple rapid method of evaluating features such as variability with depth and hard and soft layers.

D Standard Practice of Sampling Processed Peat Materials. D Standard Test Method for Total Nitrogen in Peat Materials. D Standard Test Methods for Moisture, Ash, and Organic Matter of Peat and Other Organic Soils. D Standard Test Method for pH of Peat Materials.

D Standard Test Method for Direct Tensile Strength of Intact Rock Core Specimens. De2 Standard Test Method for Density of Soil in Place by the Drive-Cylinder Method. D Standard Practice of Sampling Processed Peat Materials. D Standard Test Method for Total Nitrogen in Peat Materials.

The strength behavior of frozen soils, as with any other soil, is dependent on a number of factors, including soil type, temperature, confining stress, relative density, and strain rate. Frozen soils exhibit higher strength than unfrozen soils.

In general, frozen soil strength increases as temperature decreases and confining stress increases. The test results show that the stress-strain curves of frozen silt mainly includes three parts: the linear elastic deformation part, the damage evolution part, and the post-peak strain softening.

The book covers topics such as the properties and classification of soils such as tills and other kinds of soils related to cold climates, tropical soils, and organic soils such as peat. The text also includes the engineering behavior and properties, classification and description, discontinuities, and weathering of rocks and rock masses.

Ray Peat Forum Portal Forums > Resources, Diet, Testimonials, Logs > Ray Peat Resources & Quotes > SALE EXTENDED: Thanksgiving Sale 12% Off @ & Till December 7th With Coupon Code: ThanksStandard Test Method for Direct Tensile Strength of Intact Rock Core Specimens: D - Standard Test Method for Splitting Tensile Strength of Intact Rock Core Specimens: D - Standard Test Method for Determining In Situ Modulus of Deformation of Rock Mass Using Rigid Plate Loading Method: D - D Test Method for Determining the In Situ Modulus of Deformation of Rock Mass Using a Radial Jacking Test D Test Method for Hydraulic Conductivity of Essentially Saturated Peat D Test Method for Permeability of Rocks by Flowing Air.