The uniaxial compressive strength of a rock under static loading often decreases with an increasing temperature at which the rock has been heat-treated before strength testing. This conclusion is drawn from a great number of experiments [1,2,4,8,9,11,17–19]. The higher the temperature is, the lower the strength. Some results for uniaxial compressive strength σ c and tensile strength σ t
The uniaxial compressive strength (UCS) of rock is an important parameter required for design and analysis of rock structures, and rock mass classification. Uniaxial compression tests are a direct
01/01/2015· 1. Introduction. Unconfined compressive strength (UCS) determination of rocks plays a significant role in the analysis of geotechnical problems such as dam and tunnel design, drilling and mechanical rock excavation .The UCS of the rock is determined directly by testing the compressive behavior of the rock specimens under axial load in the laboratory.
Soft rock is a term that usually refers to a rock material with a uniaxial compressive strength (UCS) less than 20 MPa. This low strength range might be influenced by physical characteristics, such as size, saturation, weathering and mineral content. A number of uniaxial compression tests have been conducted onto soft rock samples. The results showed that the strength reduced significantly in
04/06/2015· Estimating compressive strength. General rock failure criterion can be reduced to a few parameters dependent on lithology (m) and the uniaxial compressive strength (C 0).Lithology is commonly derived during log analysis, so m may be estimated (Table 1).What is needed still is an initial measure of rock strength provided by C 0. C 0 can be estimated from porosity or sonic velocities,
It could be seen from the table that the uniaxial compressive strength and peak strain of the soft rock and hard rock are close to the aforementioned test results, which confirms the reliability of the simulation results and lays a foundation for the later triaxial compression simulation analysis. Thickness ratio (%) Uniaxial compressive strength (MPa) Peak strain (10 −2) Calculated value
THE UNIAXIAL COMPRESSIVE STRENGTH OF SOFT ROCK D. S. Agustawijaya Lecturer, Department of Civil Engineering, Faculty of Engineering, Mataram University, Mataram, Indonesia Email: [email protected] ABSTRACT Soft rock is a term that usually refers to a rock material with a uniaxial compressive strength (UCS) less than 20 MPa. This low strength range might be
1-F Rock Strength How We Measure Rock Strength Simple measurements (called “index ” tests) Uniaxial Compressive Strength (UCS), σ′3 = 0 Tensile strength (pure tension, hard for rocks!) Indirect tensile test (Brazilian test) Point-load, beam-bending, scratch
5.2 Method C, uniaxial compressive strength of rock is used in many design formulas and is sometimes used as an index property to select the appropriate excavation technique. Deformation and strength of rock are known to be functions of confining pressure. Method A, triaxial compression test, is commonly used to simulate the stress conditions under which most underground rock masses exist.
TESTING OF INTACT ROCK FOR STRENGTH 2.1 Uniaxial Compression 2.2 Point Load Testing 2.3 Uniaxial Tension 2.4 Indirect Tension Tests 2.5 Shear Tests 2.6 Confined Compression Tests (Triaxial Tests) 2.7 Biaxial and Multiaxial Tests 2.8 Other Tests 3. PARAMETERS AFFECTING ROCK STRENGTH 4. FAILURE CRITERIA FOR INTACT ROCKS AND ROCK MASSES 4.1 Mohr Criterion
The Stimson and Murray rocks are lithified fine sandstones and coarse silty mudstones, respectively, with varying compressive strengths. Thomson et al. (2013, 2014) illustrated that the energy per unit volume needed to break the bonds of a volume of rock correlates to uniaxial compressive strength
01/03/2007· The term soft rock is often referred to rock materials with a uniaxial compressive strength (UCS) lower than that of hard rocks and higher than that of soils. A rock material can be classified as a soft rock if it has a uniaxial compressive strength below 20 MPa, determined directly by uniaxial compression tests [1, 2, 3, 4].
Uniaxial compressive strength (UCS) is an important mechanical parameter for stability assessments in rock mass engineering. In practice, obtaining the UCS simply, accurately and economically has attracted substantial attention.
Uniaxial compressive strength ( c), E-modulus and the factor m i in the Hoek-Brown failure criterion for rock masses Average values from tests Tests of rocks world of intact rock samples -wide* Scandinavian rocks tested at SINTEF / NTNU *** Rating of the factor m i ** c E E c Number of tests c E E c Number ROCK MPa GPa MPa GPa of tests ure Dolomite 86 38 443 8 110 49 443 2 10.1 Limestone 107
1-F Rock Strength How We Measure Rock Strength Simple measurements (called “index ” tests) Uniaxial Compressive Strength (UCS), σ′3 = 0 Tensile strength (pure tension, hard for rocks!) Indirect tensile test (Brazilian test) Point-load, beam-bending, scratch
Rock engineers widely use the uniaxial compressive strength (UCS) of rocks in designing surface and underground structures. The procedure for measuring this rock strength has been standardized by both the International Society for Rock Mechanics [1] and American Society for Testing and Materials [2]. The method is time consuming and expensive. Indirect tests such as Point Load Index (Is(50
UNIAXIAL COMPRESSIVE STRENGTH OF ROCK MATERIALS 1. SCOPE This method of test is intended to measure the uni- axial compressive strength of a rock sample in the form of specimens of regular geometry. The test is mainly intended for strength classification and characterization of intact rock. 2. APPARATUS (a) A suitable machine shall be used for applying and measuring axial load to
For the uniaxial or unconfined compressive strength test a right circular cylinder of the material is compressed between the platens of a testing machine as illustrated in Fig. 8.1. The compressive strength is then defined as the maximum load applied to crush the specimen divided by the cross-sectional area. Rock strength has been found to be size dependent because of the cracks and
This test method specifies the apparatus, instrumentation, and procedures for determining unconfined compressive strength of intact rock core specimens. This procedure is identical to ASTM D 2938 except that the cores are tested after cutting without grinding, and neoprene caps are used on the specimen ends. Unconfined Compressive Strength Test Procedure Check the ability of the spherical
Rock engineers commonly use the unconfined compressive strength [UCS] of rocks for designing the underground structures. The standardized ASTM and ISRM are used to measure the rock strength generally [6-9]. Above method to determine the compressive strength (UCS) is time consuming and expensive. Field tests such as point load index [I 50] and indirect tension strength are used to predict
01/03/2007· The term soft rock is often referred to rock materials with a uniaxial compressive strength (UCS) lower than that of hard rocks and higher than that of soils. A rock material can be classified as a soft rock if it has a uniaxial compressive strength below 20 MPa, determined directly by uniaxial compression tests [1, 2, 3, 4].
Uniaxial compressive strength (UCS) of rock mass is very important parameter for the design of rock structures and can be measured directly and indirectly in laboratory. Key Terms in this Chapter Rock Material : A continium or polycrystalline solid between discontinuities consisting of an aggregate of minerals or grains.
Cryptocrystalline flint is an extremely hard siliceous rock that is found in chalk formations. The chalk is frequently a prefered rock type, which in recent decades is often used as a host for underground rock caverns and tunnels in Europe and North America. A reliable estimation of the uniaxial compressive strength (UCS) of the extremely strong flint, with an average UCS of about 600 MPa will
Tiryaki (2008) upon estimating the uniaxial compressive strength of intact rock material with the machine excavation of rocks. The input data comprised density, NCB cone indenter and Shore scleroscope hardness. The model was based on testing of 44 samples that had a wide range of strength, from very soft to very hard rocks. According to the available literature, the models based on
International Journal of Rock Mechanics & Mining Sciences 43 (2006) 554–561 Estimating the uniaxial compressive strength of a volcanic bimrock H. Sonmeza,, C. Gokceoglua, E.W. Medleyb, E. Tuncaya, H.A. Nefesliogluc aDepartment of Geological Engineering, Applied Geology Division, Hacettepe University, 06532 Beytepe, Ankara, Turkey bMedley GeoConsultants, 1554 Winding Way, Belmont,
This test method specifies the apparatus, instrumentation, and procedures for determining unconfined compressive strength of intact rock core specimens. This procedure is identical to ASTM D 2938 except that the cores are tested after cutting without grinding, and neoprene caps are used on the specimen ends. Unconfined Compressive Strength Test Procedure Check the ability of the spherical
i is the parameter for intact rock in the Hoek -Brown failure criterion for rock masses by Hoek et a l. (1998). Values in parenthesis have been estimated by Hoek et al (1992); values with question mark have been assumed 2) For clays the values of the uniaxial compressive strength is based on ISRM (1978), refer to Table 2.7.
The uniaxial compressive strength for the rock mass, σc, rockmass,can be expressed by setting σ3 = 0 in Equation 2.1 thus obtaining σc, rockmass =σc s . (2.2) The uniaxial tensile strength of the rockmass, σt, rockmass,can be found by setting σ1 = 0 in Equation 2.1, thus yielding c (m m s) t 4 2 2, rockmass = − + σ σ . (2.3)
Rock engineers commonly use the unconfined compressive strength [UCS] of rocks for designing the underground structures. The standardized ASTM and ISRM are used to measure the rock strength generally [6-9]. Above method to determine the compressive strength (UCS) is time consuming and expensive. Field tests such as point load index [I 50] and indirect tension strength are used to predict
1.12.1952 rock sample Uniaxial compressive strength 72 2277 6597 2,89 Uniaxial tensile strength 12 249 316 1,27 Triaxial strength 13 261t 964 3,69 Modulus ofelasticityt 54 607 3072 5,06 Poisson's ratio:j: 53 565 2882 5,10 I TOTAL (first three I properties) 97 2787 7877 2,83 TABLE II SUMMARY OFTHE CSIR ROCK TESTING SERVICES. TOTHE MINING INDUSTRY DURING PAST 20YEARS NOTES:
01/03/2007· The term soft rock is often referred to rock materials with a uniaxial compressive strength (UCS) lower than that of hard rocks and higher than that of soils. A rock material can be classified as a soft rock if it has a uniaxial compressive strength below 20 MPa, determined directly by uniaxial compression tests [1, 2, 3, 4].
Soft rock is a term that usually refers to a rock material with a uniaxial compressive strength (UCS) less than 20 MPa. This low strength range might be influenced by physical characteristics, such as size, saturation, weathering and mineral content. A number of uniaxial compression tests have been conducted onto soft rock samples. The results showed that the strength reduced significantly in
Cryptocrystalline flint is an extremely hard siliceous rock that is found in chalk formations. The chalk is frequently a prefered rock type, which in recent decades is often used as a host for underground rock caverns and tunnels in Europe and North America. A reliable estimation of the uniaxial compressive strength (UCS) of the extremely strong flint, with an average UCS of about 600 MPa will
Uniaxial Compressive Strength of Rock inc sample prep 54-165mm diameter cores ISRM Suggested Method for determining uniaxial compressive strength : 54.60: per test: 12.06a : Uniaxial Compressive Strength of Rock Materials with sample preparation for 170-250mm Diameter Cores. ISRM Suggested Method for determining uniaxial compressive strength : 60.90: per test: Testing
Although there is a high correlation between the surface hardness and the uniaxial compressive strength (UCS) of intact rocks, the SRH provides only a crude estimate for the UCS of rocks. SRH numbers reflect the outer surface of rocks and a depth of 30–50 mm. It is not sensitive to the intrinsic properties of the rocks such as texture, saturation, porosity and micro-fractures controlling the
i is the parameter for intact rock in the Hoek -Brown failure criterion for rock masses by Hoek et a l. (1998). Values in parenthesis have been estimated by Hoek et al (1992); values with question mark have been assumed 2) For clays the values of the uniaxial compressive strength is based on ISRM (1978), refer to Table 2.7.
Rock engineers commonly use the unconfined compressive strength [UCS] of rocks for designing the underground structures. The standardized ASTM and ISRM are used to measure the rock strength generally [6-9]. Above method to determine the compressive strength (UCS) is time consuming and expensive. Field tests such as point load index [I 50] and indirect tension strength are used to predict
The uniaxial compressive strength for the rock mass, σc, rockmass,can be expressed by setting σ3 = 0 in Equation 2.1 thus obtaining σc, rockmass =σc s . (2.2) The uniaxial tensile strength of the rockmass, σt, rockmass,can be found by setting σ1 = 0 in Equation 2.1, thus yielding c (m m s) t 4 2 2, rockmass = − + σ σ . (2.3)
1.12.1952 rock sample Uniaxial compressive strength 72 2277 6597 2,89 Uniaxial tensile strength 12 249 316 1,27 Triaxial strength 13 261t 964 3,69 Modulus ofelasticityt 54 607 3072 5,06 Poisson's ratio:j: 53 565 2882 5,10 I TOTAL (first three I properties) 97 2787 7877 2,83 TABLE II SUMMARY OFTHE CSIR ROCK TESTING SERVICES. TOTHE MINING INDUSTRY DURING PAST 20YEARS NOTES:
28/04/2014· Uniaxial compressive strength of rock may be predicted from the following equation. q c = 22*I s50 Mpa. Report. The corrected mean value of the point load strength index I s50 is reported in Mpa. 3. Block or Irregular Lump Test Block or Irregular lump Test Procedure. This method of test is conducted on rock block or irregular samples. Minimum of 10 test specimens are required to find out