Paper No. 8
Presentation Time: 10:00 AM

STABILITY ANALYSIS OF DISCONTINUOUS ROCK SLOPES FOR THE LH OPEN PIT LIMESTONE MINE IN KOREA


CHUNG, So-Keul1, PARK, Eui-Seob2, JUNG, Yong-Bok2, SUNWOO, Choon2, PARK, Chan2, LEE, Byung-Joo3, KIM, Hyun-Woo2, KANG, Sang-Soo1 and KANG, Jung-Seok1, (1)Exploration Geophysics and Mining Engineering Department, Korea Institute of Geoscience and Mineral Resources, 124, Gwahang-no, Yuseong-gu, Daejeon, 305-350, South Korea, (2)Underground Space Research Team, Korea Institute of Geoscience and Mineral Resources, 124, Gwahang-no, Yuseong-gu, Daejeon, 305-350, South Korea, (3)Geologic Hazards Department, Korea Institute of Geoscience and Mineral Resources, 124, Gwahang-no, Yuseong-gu, Daejeon, 305-350, South Korea, skchung@kigam.re.kr

This paper deals with a stability analysis of large scale rock slopes in the LH open pit limestone mine in Korea. The slope stability conditions at the LH open pit mine are governed mainly by the orientations of very continuous joints and faults. As a result of unfavorable combinations of directions of major joints and faults, local stability problems have occurred at several places on the slope walls.

A series of extensive geological surveys were carried out to investigate the geological features including joints and faults, by using the surface geological mapping and 3D laser scanning. Based on the stereographic projection technique it has been found that the orientation of main joints was divided into four sets in the area. When these joints are oriented approximately parallel to the slope wall, and have a dip angle steeper than that of the slope, sliding tends to occur unless the necessary stabilizing measures are taken in time. So, stability problems due to wedge and plane failure can occur locally in the slope wall.

The failure mechanisms of the slopes were studied by means of a graphical method and numerical modeling. Two- and three-dimensional numerical analyses based on the strength reduction method were conducted to investigate failure mechanisms in more detail and to explore the general characteristics of slope failure. From the numerical results, the overall stability of slopes was estimated by the criteria of the minimum value of safety factors and possibility of failure.

As the rock mass class of the slope is greatly affected by the quality of blasting, a controlled perimeter blasting is a prerequisite for the stability of slopes and also for ensuring safe working conditions at lower levels of the mine.

As an early detection and remedy for unstable conditions is very important for economy and safety of the open pit mining, various monitoring techniques can be suggested for detecting unstable conditions of rock slopes and taking the necessary stabilizing measures in time.

Handouts
  • GSA_T75_No106-8(skchung)_rev01.pptx (34.0 MB)