ABSTRACT
The
research deals with estimating some mechanical properties of rock from in-situ
rebound value in Oreke open pit quarry ,N-Type
Schmidt rebound hammer data were collected from Oreke open pit .the data
were collected with the view to ascertain the suitability of Schmidt hammer for
quick ,cheap and less cumber some estimation of the uniaxial compressive
strength of marble .The data collection was strictly carried out by ASTM and
suggested equation by different authors.Uniaxial
compressive strength,density, young modulus were determined using
value conversion graph.uniaxial
compressive strength for location 1 was 70MPa which mean the
rock is medium in classification and location 2 and 3 was 55MPa this implies
that is medium in term of strength , type is competent metamorphic rock.
TABLE OF CONTENTS
TITLE PAGE i
CERTIFICATIONÂ Â ii
DEDICATIONÂ Â iii
ACKNOWLEDGEMENTÂ iv
TABLE OF CONTENTSÂ vi
LIST OF TABLESÂ viii
LIST OF FIGURESÂ ix
CHAPTER ONEÂ Â 1
1.0Â Â Â Â Â Â Â Â Â Â INTRODUCTIONÂ Â 1
1.1Â Â Â Â Â Â Â Â Â Â AIM AND OBJECTIVES. 2
1.2Â Â Â Â Â Â Â Â Â Â STATEMENT OF THE PROBLEMÂ Â Â 2
1.3Â Â Â Â Â Â Â Â Â Â SCOPE OF THE PROJECTÂ 3
1.4Â Â Â Â Â Â Â Â Â Â JUSTIFICATION OF THE PROJECTÂ 3
1.5Â Â Â Â Â Â Â Â Â Â LOCATION OF THE STUDY AREAÂ Â 3
CHAPTER TWOÂ Â 4
2.0Â Â Â Â Â Â Â Â Â Â LITERATURE REVIEWÂ Â Â 4
2.1Â Â Â Â Â Â Â Â Â Â CONCEPT OF SCHMIDT REBOUND HAMMERÂ Â 4
2.2Â Â Â Â Â Â Â Â Â Â GEOLOGICAL FORMATION OF MARBLEÂ Â 8
2.3Â Â Â Â Â Â Â Â Â Â MECHANICAL PROPERTIES OF MARBLEÂ Â 11
CHAPTER THREEÂ Â 14
3.0Â Â Â Â Â Â Â Â Â Â RESEARCH METHODOLOGY (DESK WORK) 14
3.1Â Â Â Â Â Â Â Â Â Â DETERMINATION OF BULK DENSITYÂ Â 14
3.2Â Â Â Â Â Â Â Â Â Â PROCEDURE FOR COLLECTING REBOUND HAMMER VALUEÂ Â 15
3.3          CONVERTED FROM N – L TYPE DATA  16
3.4Â Â Â Â Â Â Â Â Â Â ESTIMATING UNIAXIAL COMPRESSIVE STRENGTH OF MARBLE (UCS) 16
3.5Â Â Â Â Â Â Â Â Â Â ESTIMATING OF DENSITYÂ Â 18
3.6          ESTIMATING OF YOUNG’S MODULUS 19
CHAPTER FOURÂ Â 21
4.0Â Â Â Â Â Â Â Â Â Â RESULT AND DISCUSSIONÂ Â 21
4.1Â Â Â Â Â Â Â Â Â Â RESULTSÂ 21
4.1.1Â Â Â Â Â Â DETERMINATION OF BULK DENSITYÂ Â 21
4.1.2Â Â Â Â Â Â PROCESSING PROCEDUREÂ Â 24
4.1.3Â Â Â Â Â Â CONVERTED FROM N-TYPE TO L-TYPE DATAÂ Â 25
4.1.4Â Â Â Â Â Â ESTIMATION UNIAXIAL COMPRESSIVE STRENGTHÂ Â 26
4.1.5Â Â Â Â Â Â ESTIMATED DENSITYÂ Â 28
4.2          ESTIMATED YOUNGʹS MODULUS 29
4.3Â Â Â Â Â Â Â Â Â Â DISCUSSIONÂ Â 31
CHAPTER FIVEÂ Â 32
5.0Â Â Â Â Â Â Â Â Â Â CONCLUSION AND RECOMMENDATIONÂ Â 32
5.1Â Â Â Â Â Â Â CONCLUSIONÂ Â 32
5.2Â Â Â Â Â Â Â RECOMMENDATIONÂ Â 32
             REFERENCES 33
LIST OF TABLES
TABLES TITLE PAGE
 4.1:            Determination of Bulk Density for Location 1; 22
4.2: Â Â Â Â Â Â Â Â Â Â Â Â Density Test Result for Location 2Â 22
 4.3:            Density Test Result for Location 3 23
 4.4:            Field Rebound Values 24
 4.5:            Standard Procedure of Bulk Density Determination 30
 4.6:            Standard for Uniaxial Compressive Strength (UCS) 31
LIST OF FIGURES
FIGURES TITLE PAGES
1: Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Details of an L type Schmidt hammer 7
2:                          Conversion Graph 27
CHAPTER ONE
1.0Â Â Â Â Â Â INTRODUCTION
Rock mechanics engineers design structures built in rock for various purposes, and therefore need to determine the properties and behavior of the rock. The UCS of rocks is one of the important input parameters used in rock engineering projects such as design of underground spaces, rock blasting, drilling, slope stability analysis, excavations and many other civil and mining operations. ISRM (1981) testing of this mechanical property in the laboratory is a simple procedure in theory but in practice, it is among the most expensive and time-consuming tests. This calls for transportation of the rock to the laboratory, sample preparation and testing based on the international standards. In order to carry out these standard tests, special samples, such as cylindrical core or cubical samples, need to be prepared. Preparing core samples is difficult, expensive and time-consuming. Moreover, the preparation of regular-shaped samples from weak or fractured rock masses is also difficult. Under these circumstances, the application of other simple and low-cost methods to carry out the above tasks with acceptable reliability and accuracy will be important. Therefore, indirect tests are often used to estimate the UCS, such as Schmidt hammer, point load index and sound velocity. Indirect tests are simpler, require less preparation and can be adapted more easily to field testing (Feneret al. 2005).
The Schmidt hammer rebound hardness test is a simple and non-destructive test originally developed in 1948 for a quick measurement of USC and later was extended to estimate the hardness and strength of rock. The mechanism of operation is simple: a hammer released by a spring, indirectly impacts against the rock surface through a plunger and the rebound distance of the hammer is then red directly from the numerical scale or electronic display ranging from 10 to 100. In other words, the rebound distance of the hammer mass that strikes the rock through the plunger and under the force of a spring, indicates the rebound hardness. Obviously, the harder the surface, the higher the rebound distances. (Torabiet al. 2010; Schmidt, 1951).