EFFECT OF CYCLIC LOADING ON THE CHANGES OF LIMESTONE STRENGTH USING IMPACT TEST METHOD

• Main Author: Pamungkas, Lukas
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/76840
• Institution: Institut Teknologi Bandung

Mining activities carried out are considered to have an impact, one of which is the occurrence of rock fatigue. Rock fatigue occurs because the activity is carried out cyclic so that the load received by the rock will increase until it can finally cause collapse. Examples of repetitive loading are vibration due to blasting and the use of heavy equipment. To determine the effect of cyclic loading on rock strength, research was conducted using impact test method. The research started with physical properties test and ultrasonic wave propagation speed test, followed by uniaxial compressive strength test of the test samples. In this study, limestone test samples were used. The test sample was given an impact from a pressing iron dropped at a height of 0,2 m (19,72 MPa), 0,3 m (24,15 MPa), 0,4 m (27,89 MPa), 0,5 m (31,18 MPa), 0,75 m (38,19 MPa), 1 m (44,10 MPa), then calculated how many impacts were required until the test sample broke. In the second test, the test sample was impacted with a height of 0.5 m for 5, 10, and 15 times. Then, the test samples were subjected to uniaxial compressive strength test and the compressive strength, Young's Modulus, and Poisson's Ratio values were compared before and after the impact test to see the changes in the strength of the test samples. The result of the research is that the higher the pressing iron is dropped or the greater the dynamic stress applied, the fewer the number of collisions required to make the test sample break. Based on the phenomenon of test sample rupture, there are three stages of test sample rupture, namely the erosion of the test sample surface, the formation of fractures, and the rupture of the test sample. After the impact test, the compressive strength and Young's Modulus values decreased, while the Poisson's Ratio value was not affected by the impact test.