Taking the soil-structure interaction into account in assessing the loading of a structure in a mining subsidence area

Underground mining of raw materials is often the cause of ground movements at the surface. Whether planned or accidental, such movements can cause considerable damage to structures located within the area of influence of underground mining works. Examples are the recent subsidences that took place at the end of the 1990s in the Lorraine iron mining field. A better understanding is necessary of how ground surface movements can be imparted to the supported structure and damage it. Indeed, it is too often considered that damage depends only on ground strain and no account has been taken of soil-structure interaction phenomena, which may affect considerably the structural behaviour. The stiffness of a structure is quantified in comparison to that of the ground as regards the various movements of the ground surface. This investigation highlights situations in which ground movements are integrally imparted to a structure. When this is not the case, the resulting complex soil-structure interaction phenomena is analysed. For this purpose, a finite-element software is used to generate models incorporating the ground material and a supported rigid structure. The ground movements are broken down into two basic movements in order to highlight the impact and the relative importance of one of these movements: ground curvature and horizontal strain. Structural stresses are quantified for different mechanical properties of the ground and the structure, as well as for different amplitudes of ground movement. This investigation made it possible to devise a methodology for analyzing structures in mining subsidence areas in order to determine cases in which soil-structure interaction phenomena must be considered. The investigation made it possible to hierarchically organize the ground and structure parameters, the variability of which has a significant effect on the behaviour of the structure affected by mining subsidence. (C) 2002 Elsevier Science Ltd. All rights reserved.