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The uniaxial compression test (see Test Method D 7012) is used to determine compressive strength of rock specimens. However, it is a time-consuming and expensive test that requires significant specimen preparation and the results may not be available for a long time after the samples are collected.
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impossible to determine through normalized testing [1, 2, 3]; however, it may be determined with a simple geologist hammer or with the Schmidt hammer, among others [3]. But for more approximate values it may be obtained via simple in situ or laboratory tests, like the Brazilian traction test or the Point Load Test (PLT).
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The GCTS PLT-2W Point Load Testing Device is an easy-to-use system made of light-weight, high-strength anodized aluminum that remains extremely accurate while being very portable. Due to the compact design, this test can be performed either in a laboratory or in the field. The PLT-2W is used to determine the rock strength index of a sample, which can be used to estimate the uniaxial ...
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such as the point load test can be used in the field to reduce the time and cost of compressive strength tests. 5.2 The point load strength test is used as an index test for strength classification of rock materials. The test results should not be used for design or analytical purposes. 5.3 This test method is performed to determine the point ...
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As the standard laboratory tests to determine UCS require machined specimens, indirect tests are often used to predict UCS. ''The possibility of using relatively unprepared specimens for a rock strength test has always been attractive, and for this the point load test seems poten- …
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uniaxial tension using the Instron Model 4505. The samples were dog-bone structures to localize the point of failure to the center of the samples during testing (Fig. 2.1). The initial sample dimensions (width and thickness) were measured, and then the samples were mounted into the fixed lower base of the Instron 4505 (Table 2.1, Fig. 2.2).
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The point load test has been reported as an indirect measure of the compressive or tensile strength of the rock. D'Andrea et al.[4] performed uniaxial compression and the point load tests on a variety of rocks. They found the following linear regression model to …
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the strength index test used a speed control Instron machine with a maximum load cell of 5 kN. Specimens were core samples with a diameter of 37.5 mm, and a thickness of 20 mm. Similar rocks with that for the uniaxial compression tests were tested in the point load tests. The degree of weathering was described according to
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Uniaxial Tension Testing Introduction Uniaxial tension is used, like cantilever beam bending, to determine the Young's Modulus of a material. Uniaxial tension testing is most effective when performed on a homogeneous material, such as steel or aluminum. Young's Modulus is the slope of the line created by stress-strain coordinate pairs (see
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Rusnak J, and Mark C (1999) Using the point load test to determine the uniaxial compressive strength of coal measure rock. Proceedings of 19th Int Conference on Ground Control in Mining: 362–371. Sarkar K, Vishal V, Singh T (2012) An empirical correlation of index geomechanical parameters with the compressional wave velocity.
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Figure 8-1: Point Load Test Apparatus. (Adopted from Roctest) 8 - 4 σu = Uniaxial Compression Test AASHTO ASTM -D 2938 Purpose To determine the uniaxial compressive strength of rock (qu = F u = F C). Procedure In this test, cylindrical rock specimens are tested in compression without lateral confinement. The test procedure is simila r to the ...
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Download Full PDF Package. ... The point load tests have been run on the ylinder The uncorrected point load strength, Is, is specimen with the diameter ranging from 70 to calculated as: 80 milimeters and different heights. ... The Point Load Tester. USING THE POINT LOAD TEST TO DETERMINE THE UNIAXIAL COMPRESSIVE STRENGTH OF COAL MEASURE ROCK ...
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1.5 This test method does not cover which type of specimen should be tested or whether anisotropic factors should be considered. The specifics of the point load test program need to be developed prior to testing and possibly even before sampling. Such specifics would be dependent on the intended use of the data, as well as possible budgetary constraints and possible other factors, which are ...
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1. Introduction. The determination of basic mechanical properties of rocks is crucial to a specific engineering project. Several mechanical properties, including uniaxial compressive strength (UCS), have become widely accepted parameters for rock design projects (Baskerville, 1987).From past to present, direct and indirect methods have been used to determine UCS of rocks in field and …
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Abstract and Figures. Point load testing is used to determine rock strength indexes in geotechnical practice. The point load test apparatus and procedure enables economical testing of core or lump ...
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BS 5930 (1981) provides no help for engineers wishing to take advantage of the quick, cheap rock strength assessment provided by the point load test introduced in 1972. The paper discusses the correlation factors obtained as a result of testing the same material from the Corallian strata at Weymouth by point load and uniaxial compression. The considerable advantage obtained using the …
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Rock Mech. Rock Engng. (2006) 39 (5), 483–490 DOI 10.1007/s00603-006-0082-y Technical Note Predicting Uniaxial Compressive Strength by Point Load Test: Significance of Cone Penetration By A. Basu and A. Aydin Department of Earth Sciences, The University of Hong Kong, Hong Kong SAR, China Received July 15, 2005; accepted January 3, 2006 Published online March 30, …
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To determine dimensions for a safe design for normal stress in a uniform member, we must locate the place were the normal internal reaction is the greatest, perhaps by the method of sectioning or by drawing a load diagram. There are times when the area is not uniform, or dimensions change, but those scenarios will be covered under stress ...
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View cdc_9302_DS1.pdf from ECONOMICS 234 at Harvard University. USING THE POINT LOAD TEST TO DETERMINE THE UNIAXIAL COMPRESSIVE STRENGTH OF COAL MEASURE ROCK John Rusnak, Director of Geology Peabody
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Indirect methods such as the point load test have been proposed to determine the unconfined compressive strength of shales and other soft rocks. It is current practice to use 24 as the conversion factor between the point load strength, I s, and the unconfined compressive strength, s f (s f .= 24 I s ).
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Predicting Uniaxial Compressive Strength by Point Load Test: Significance of Cone Penetration Download PDF. ... Point-load testing of brittle materials to determine tensile strength and relative brittleness. In: Proc., ... Point load test, cone penetration, uniaxial compressive strength, weathering grade, granite. Download PDF.
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2.2 Point Load Testing In order to overcome many of the problems associated with the unconfined compression test, Broch and Franklin (1972) proposed a testing method called the Point Load Test. The test consists of squeezing pieces of rock diametrically between two hardened steel cones. The test set-up is shown in Figure 1.
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represented by point D. Total elongation, which includes both elastic and plastic deformation, is the amount of uniaxial strain at fracture and is depicted as strain at point Z. Percent elongation at break is determined by removing the fractured specimen from the grips; fitting the broken ends together and measuring the distance between gage marks.
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Point load testing is used to determine rock strength indexes in geotechnical practice. The point load test apparatus and procedure enables economical testing of core or lump rock samples in either a field or laboratory setting. In order to estimate uniaxial compressive strength, index-to-strength conversion factors are used.
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tensile test. In this test, a load is applied along the longitudinal axis of a circular test ... a bar subjected to uniaxial extension. The slope of the straight-line portion of the stress-strain diagram is called the Modulus ... point in the body. A homogeneous material may or may not be isotropic.
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The triaxial test is one of the most versatile and widely performed geotechnical laboratory tests, allowing the shear strength and stiffness of soil and rock to be determined for use in geotechnical design. Advantages over simpler procedures, such as the direct shear …
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separation between the platens, the point load strength index (I s) is defined as IS = P/D 2 (8.4) Corrections are applied to I S to allow for specimen size and shape to yield the size corrected point load strength index (I S50) which is defined as the value of I S for a diametral test with D equal to 50mm.
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Gao-Feng Zhao. The point load test (PLT) has been considered a flexible approach to estimate the uniaxial compressive strength (UCS) of rocks. Previously, empirical equations were obtained by ...
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H. Salah et al. 299 ing Equation (1) is used to determine the UCS, Where (P u) is the ultimate load and (d) is the sample's diameter: (0.785 2)UCS P d= u (1) 4. Point Load Test The ASTM-D5731-08 [8] code gave a clear justification for the use of the point load test.
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Use the figure to calculate a best-fit n value for each material and compare this with the uniform strain calculated in Problem 2. Why are they different, in view of Eq. 1.16? 5. For each of the explicit hardening laws presented in Problem 2, plot the engineering stress-strain curves and determine the maximum load point graphically.
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Point Load test is an alternate method that can be used to adequately predict the uniaxial compressive strength of a rock material using a portable and simpler equipment. Schmidt Hammer Rebound test is also a technique used for this purpose but, it is admitted that its results are far more variable and affected by testing methods.
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The Point Load Tester. USING THE POINT LOAD TEST TO DETERMINE THE UNIAXIAL COMPRESSIVE STRENGTH OF COAL MEASURE ROCK John Rusnak, Director of Geology Peabody Group St. Louis, MO Christopher Mark, Rock Mechanics Team Leader National Institute for Occupational Safety and Health Pittsburgh, PA ABSTRACT Point load testing is used to determine rock ...
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