Year

2019

Degree Name

Master of Engineering (Civil)

Department

School of Civil, Mining and Environmental Engineering

Abstract

These days, safety in coal mining has become an important issue. Lots of accidents and casualties occur on a regular basis. To address this problem, all engineers and designers need to recognise that all workers and personnel, who work in the mining industry, have a safe place to work. Hence, there is a need for stabilisation of underground working areas, before and after excavations. The use of long tendon support elements (cable bolts) is now common practice in modern underground coal mines, hard rock mines, tunnels, and other underground structures. Because of characteristics of the cables’ material makeup, they contribute significantly to the overall ground reinforcement provided by any support system. Therefore, the behaviour of cable bolts in tension and shear plays a vital role in maintaining a safe underground environment. Numerous methods of testing and various apparatus have been employed through four decades to understand the behaviour of cable bolts in tension is a common method of evaluating the load transfer in shear and pull testing.

In this thesis study firstly, the behaviour of encapsulated cable bolts in the rock strata’s has been examined both in tension and in shear concerning load transfer capacity. In the past, there were methods of pull-out tests in the laboratory investigating the effect of various factors on the load transfer performance of cable bolts. The performance of different types of cable bolts with a variety of diameters of both plain and indented cables, tested in composite/concrete medium with different water to cement ratios. Minova Axially Split Embedment Apparatus (MASEA) and The Multi Diameter Laboratory Short Encapsulation Pull Test Apparatus (MDLSETA) were used in the study. This piece of work also included the shear testing of the same cable bolt types using the double shear apparatus. The various factors affecting the shear performance of cable bolts were examined along with the effects of the pretension load face property of cable bolts, the ultimate tensile capacity and the strength of the grout. The most important objective of this part of the study was to determine the ability of the MASEA for determining load transfer characteristics of cable bolts. In this case, although some recent studies have been undertaken by (Thomas, 2012) and (Hagan et al., 2015) to investigate the performance of cable bolts in pull testing, there are still some deficiencies in these methods. The weaknesses are the amount of concrete wasted, steel tubes and a sample of rocks. The very recent study by (Aziz et al., 2016a) overcomes these shortcomings. The use of steel as a means of confinement which is substituted for rock and comparing the results with previously published papers has helped to validate the capability of MASEA to supply precise results. Besides, the use of an anti-rotation steel box is effectively preventing cables from rotating during pull testing...

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.