American society for testing and materials reprinted from the. There is a plethora of correlations for estimating the ucs from the point load strength index, as summarized in table 1. Correlation between rqd and rock quality after deere, 1964. Digital point load tester, pointload strength test originally developed at imperial college, london, the apparatus comprises a twocolumn fixed crosshead frame and a hand operated hydraulic jack. Astm d573116 standard test method for determination of. Digital point load tester material testing equipment matest. The point load test has often been reported as an indirect measure of the compressive or tensile strength of rock 1,2,3,4. Pdf correlation between uniaxial strength and point load. The applied load is measured by a high precision electric load cell with a digital display unit range 056kn proving. These factors have been proposed by various researchers and are dependent upon rock type. The sizecorrected point load strength index, is50, of a rock specimen is defined as the value of is that would have been measured by a diametral test with d 50 mm. Pdf an index test for strength classification of rock materials is described. The test consists of squeezing pieces of rock diametrically between two hardened steel cones. I need to perform lab test on rock for which i need point load testtab.
The point load strength index i s50 is empirically correlated to the ucs. Aug 05, 2018 mine 323 point load strength index lab 1 duration. This is an index test and is intended to be used to classify rock strength. Prediction of the uniaxial compressive strength and. The test was conducted for rock cores at about 30 meters interval. In order to estimate uniaxial compressive strength, indextostrength conversion factors are used. Used to determine the strength values of a rock specimen, both in the field and in the laboratory.
Point load strength is as a measure for the determination of rock strength and for estimating uniaxial unconfined compressive strength ucs are described and both put together and used for rock strength classification of brittle and hard rocks. Table 2 from using the point load test to determine the. To calculate safe bearing capacity suitable factor of safety is applied. For a cylindrical rock specimen diameter d and the four point loading arrangement as shown in fig. Pdf using the point load test to determine the uniaxial. Point load index strength astm d 5731 purpose to determine strength classification of rock materials through an index test. The point load test plt is an accepted rock mechanics testing procedure used for the calculation of a rock strength index. Simple hammer and penknife tests can be used but this approach seldom. Point load test of halfcylinder core using the numerical model. So, plate load test is helpful for the selection and design the foundation. Point load testing of weak rocks with particular reference. These factors have been proposed by various researchers and are. When a precise rock classification is essential, the most reliable method of obtaining is50 is to conduct diametral tests at or close to d 50 mm. Isrm suggested methods are explanations of recommended procedures to follow in the various aspects of rock characterisation, testing and monitoring.
It is commonly used in practice due to the ease of testing, simplicity of specimen preparation and possible field application. Brinell hardness test description the point load test is performed on rock core specimens or irregular rock fragments to obtain the point load strength index and unconfined compressive strength of the rock. They consist of a load frame for applying loads, on which a manual hydraulic jack is mounted. Point load test application for estimating compressive. The point load test apparatus and procedure enables economical testing of core or lump rock samples in either a field or laboratory setting. Plate load test to calculate bearing capacity and settlement. Point load definition what does point load mean in. Three point load test configurations are used depending on the available rock specimens. Prediction of side resistance in poor quality rock. Cdc mining using the point load test to determine the. Aim to determine point load strength index of rock as per is8764 equipments point load strength test machine a 100 mm scale attached with the loading frame pressure gauge capacity 25 kn or 50 kn depending upon the size and shape of test specimen, the point load strength index can be conducted by four different. The failure load is used to calculate the point load strength index and to estimate the uniaxial compressive strength.
If the cores being tested have approximately 50mm diameter. Point load test on schistose rocks and its applicability in predicting uniaxial compressive strength. The point load strength test is based on the indirect tensile strength test or rock core by fracturing a specimen of rock using a machine equipped with conical platens and a load measuring system. Point load test set of 10 individual determinations on one rock core or rock stick sample astm isrm. Specimens in the form of core journal ofthe south african institute ofmining and metallurgy ex f f i 50 10 are. Broch and franklin 1972 proposed a testing method called the point load test. The point load test apparatus and procedure enables economical testing. Pdf standard test method for determination of the point. For these tests, rock pieces must have a length at least 1.
Furthermore, sampling of specimen on site can be provided. The advantages of using the point load test relate to a smaller cost per unit test when compared to compressive strength testing of concrete cores and to the speed with which the test can be performed. An established load force, located at a certain point on a supporting structure. Method of determination of point load strength index. Standard test method for determination of the point load. Apr 28, 2014 aim to determine point load strength index of rock as per is8764 equipments point load strength test machine a 100 mm scale attached with the loading frame pressure gauge capacity 25 kn or 50 kn depending upon the size and shape of test specimen, the point load strength index can be conducted by four different. Pointload strength is as a measure for the determination of rock strength and for estimating uniaxial unconfined compressive strength ucs are described and both put together and used for rock strength classification of brittle and hard rocks. Questa rock pile stability study sop 77v3 page 1 sop 77v3 10302008 standard operating procedure no. A look at loaddistributing and loadsharing anchor systems. The point load test measures the point load strength index is50 of rock specimens, and their strength anisotropy index ia50, which is the ratio of point load strengths in directions that give the greatest and least values.
A complete list of all suggested methods is provided here. Civil and environmental engineering, school of mining and petroleum engineering recommended for you 5. Specimens in the form of either rock core the diametral and axial tests or irregular lumps the irregular lump test are broken by application of a concentrated load using a pair of conical platens. Point load strength index test of rock is8764 civilblog. Geological strength index for jointed rock marinos and hoek, 2000 rqd % rock quality 90 to 100 excellent 75 to 90 good 50 to 75 fair 25 to 50 poor 0 to 25 very poor table 1.
This test does not require costly specimen preparation and is a quick, simple test. Correlation between the point load index is50 and the. Procedure rock specimens in the form of core dia metral and axial, cut blocks or irregular lumps are broken by application of concentrated lo ad. The point load test apparatus and procedure enables economical testing of core or lump rock samples in.
The focus of this paper is to present the data analysis used to correlate the point load test index is50 with the uniaxial compressive strength ucs. At olkiluoto the point load test was performed on rock cores during the site investigation coredrillings. Please guide me to find point load test and other rock test in gint. The bottom of a column presents a point load on a structure. The estimated point load strength values of specimens of varying sizes and also the values corrected to a standard thickness of 50 mm, and the. This index can be used to estimate other rock strength parameters. This standard is issued under the fixed designation d 5731. Point load testing is used to determine rock strength indexes in geotechnical practice. In rock mechanics and engineering geology, the point load test is regarded as a valuable field test to give an estimate of the unconfined. Laboratory testing and interpretation of rock properties. Jul 28, 2017 mine 323 point load strength index lab 1 duration. This paper investigates the value of k for chalk and other weak rocks using published and unpublished data sets and concludes that k is not. This paper investigates the value of k for chalk and other weak rocks using published and unpublished data sets and concludes.
Rock mechanics ced 48 designator of legally binding document. A point load strength index is50 is obtained and may be used to classify rocks by strength. The test results should not be used for design or analytical purposes. A block wall represents a uniform load along a supporting structure. The isrm suggested methods downloaded are for the personal use of isrm members. Pdf the point load test for the tensile strength of rock.
The point load test is performed on rock core specimens or irregular rock fragments to obtain the point load strength index and unconfined compressive strength of the rock. The point load test for the tensile strength of rock article pdf available in geotechnical testing journal 32 june 1980 with 1,109 reads how we measure reads. The use of point load test for dubai weak calcareous sandstones. Plate load test is done at site to determine the ultimate bearing capacity of soil and settlement of foundation under the loads for clayey and sandy soils. Pressure applied by the jack extends the piston carrying the lower conical point. Procedure rock specimens in the form of core dia metral and axial, cut blocks or irregular lumps are broken by application of concentrated lo ad through a pair of spherically truncated, conical platens. Laboratory testing of intactlaboratory testing of intact rocks. The digital point load tester consists of a load frame for applying loads up to 55kn, on which a manual hydraulic jack is mounted. The estimated pointload strength values of specimens of varying sizes and also the values corrected to a standard thickness of 50 mm, and the. Point load testing of weak rocks with particular reference to. Specimen the base support is fitted to the columns of the point load test frame through the holes at its both ends and then it is attached to the ram of the frame by means. This is opposite a uniform load, which is a force evenly distributed along a supportive structure. Astmd5731 standard test method for determination of the.
Legally binding document step out from the old to the newjawaharlal nehru invent a new india. Ele international digital pointload test apparatus. Point load testing was performed in both axial and diametral orientations with unconfined compression tests performed for correlation. The point load test plt was developed as an index test to predict the uniaxial compressive strength ucs of core too broken for ucs testing. Apr 01, 2007 specimens in the form of either rock core the diametral and axial tests or irregular lumps the irregular lump test are broken by application of a concentrated load using a pair of conical platens. A look at loaddistributing and loadsharing anchor systems presented by. The point load strength index obtained from a point load test is correlated with the uniaxial compressive strength of the rock tested. Point load test results from olkiluoto area borehole cores.
Richardson 1989 conducted a point load tests of cast specimens with various diameters as 50. Point load strength index test strength of materials. Civil and environmental engineering, school of mining and petroleum engineering 2,143 views. Point load index quick evaluation for uniaxial strength field or lab setupfield or lab setup astm d 5731 procedures little sample preparation cores, pieces measure force p to crunch intact rock specimen point load index. The most common field test on rock samples is the point load test. The point load test provides a fast and economic method for evaluating the ucs of rock specimens. Smaller forces are needed, and a small and portable testing machine canbeused.
A commercially available point load test apparatus was purchased and used in a testing program on nx cores from the major types of sedimentary rock found in missouri. International society for rock mechanics the complete. Used to determine the strength values of a rock specimen both in the field and in the laboratory. Digital point load tester, point load strength test originally developed at imperial college, london, the apparatus comprises a twocolumn fixed crosshead frame and a hand operated hydraulic jack. Plate load test for calculation of bearing capacity and. Strength mpa point load index mpa field estimate of strength examples r6 extremely strong 250 10 specimen can only be chipped with a geological hammer fresh basalt, chert, diabase, gneiss, granite, quartzite r5 very strong.