Perancangan Desain Timbunan Batubara dan Pengaruhnya terhadap Kestabilan Lereng di Sekitar Rom 4 Site DMP PT Cipta Kridatama

Abstract

The increase in coal production every month at PT Cipta Kridatama Dizamatra Powerindo (DMP) site results in the need for additional Run Of Mine (ROM) to be able to accommodate the coal production produced. ROM 4 as a new ROM has not yet known the bearing capacity of the ROM base soil, the maximum height of the embankment, and the slope stability analysis. Therefore, it is necessary to conduct a geotechnical study on the bearing capacity of the base soil and slope stability around ROM 4. This study aims to design a coal stockpile design, analyze the slope stability around ROM 4, and compare FK values before and after loading under static and dynamic conditions. The methods used in the slope stability analysis are Bishop, Janbu, Morgenstern-Price, and Spencer methods. The data used are coal volume weight, base CBR value, situation map, material properties, and seismic load constant. The results showed that the optimal design of ROM 4 coal embankment based on soil bearing capacity has a maximum height of 17 m, an embankment slope angle of 36°, and a capacity of 511,594.44 tons. The FK value of the slope around ROM 4 both before and after loading under static conditions is greater than 1,3 and dynamic conditions are greater than 1,1. The method that produces the smallest FK value is Janbu 1.174. Comparison of FK values from each LEM method, in static conditions is greater than dynamic conditions. This can occur because the constant seismic load can increase the driving force of the slope so that it can reduce the FK value. While the comparison of FK values before loading is greater than after loading. This can occur because the additional load of coal and increased pore water pressure can cause the shear strength and cohesion of the soil that makes up the slope to decrease. This condition can cause a decrease in FK on the slope. The FK value of the slope around ROM 4 is declared safe because it is in accordance with the standards set by the Decision of the Minister of Energy and Mineral Resources Number 1827/K/30/MEM/2018