KARST SINKHOLES STABILITY ASSESSMENT IN CHERIA AREA, NE ALGERIA

Abstract

This research work deals with the problem of karst sinkhole collapse occurring in the last few years in Cheria area. This newly revealed phenomenon is of a major constrain in land use planning and urbanization, it has become necessary to assess the stability of these underground features before any planning operation. Laboratory testing and field work were undertaken in order to determine both intact rock and rock mass properties. All the rock mechanics testing and measurement were undertaken according to the ISRM recommendations.

It has been found that under imposed loading, the stability of the karst cavities depends on the geo-mechanical parameters (Rock Masse Rating; RMR, Geological Strength Index; GSI, and Young Modulus; E) of the host rock as well as the depth and dimensions of the gallery. It increases with RMR, GSI, E and depth and decreases as the cavity becomes wider. Furthermore, the calculation results show that a ratio (roof thickness to gallery width) of 0.3 and more indicate, a stable conditions. 

The results obtained in this work allow identifying and assessing the stability of underground karst cavities. The methodology followed in this paper can be taken as a road map in the establishment of a hazard map related to the studied phenomenon. This map will be a useful tool for the future urban extension planning in Cherea area.