2D and 3D Discrete Element Modeling of an Underground Archaeological Site in Seismic Conditions

This paper is intended to study the stability of the underground water storage cavern at the Tel Beer Sheva archaeological site, excavated in a highly jointed chalk in the Negev Desert, in Israel. Archaeological researches showed that the roof of this cavern had collapsed during the time of construction and that a massive support pillar was erected in the centre of the cavity to support the remaining roof. The same cavern with the pillar in place has remained stable through the centuries notwithstanding a number of seismic events that did occur in the area. By using the distinct element method (DEM) and the UDEC and 3DEC codes, stability analyses of the cavern were performed in static and seismic conditions. Following a back analysis of the roof failure with the massive support pillar in the centre of the cavern, the analyses were carried out with attention paid to the present cavern configuration, where the seismic action was represented with the Nuweiba earthquake (Mw = 7.1) occurred on 22 November 1995. The models were discretized based on the detailed joint sets mapping available. Particular attention was devoted to the study of wave propagation across a discontinuous rock mass.