On the use of 1g physical models for ground movements and soil-structure interaction problems

The paper focusses on the use of physical modelling in ground movements(induced by underground cavity collapse or mining/tunnelling)and associated soil-structure interaction issues.The paper presents first an overview of using 1 g physical models to solve geotechnical problems and soil-structure interactions related to vertical ground movements.Then the lg physical modelling application is illustrated to study the development of damage in masonry structure due to subsidence and cavity collapse.A largescale 1 g physical model with a 6 m^3 container and 15 electric jacks is presented with the use of a threedimensional(3D)image correlation technique.The influence of structure position on the subsidence trough is analysed in terms of crack density and damage level.The obtained results can improve the methodology and practice for evaluation of damage in masonry structures.Nevertheless,ideal physical model is difficult to achieve.Thus,future improvement of physical models(analogue materials and instrumentation)could provide new opportunities for using 1 g physical models in geotechnical and soilstructure applications and research projects.

Numerical and Geophysical Tools Applied for the Prediction of Mine Induced Seismicity in French Coalmines

The determination of the influence of mining works and the induced seismicity is essentially obtained, separately from in-situ observations and seismic analysis, field measurements (particularly surface survey) as well as from numerical investigations. The paper presents a methodology applied for the analysis of induced seismicity due to underground coalmines based on combining numerical modelling and seismic analysis. The methodology is based on the comparing between the observations, the seismic activity and the numerical modelling for establishing a close correlation between the location of seismic activity and the induced stresses. The paper presents two case studies using seismic and geotechnical investigations, the first one concerns a fatal accident affected Lorraine coalmine (East France). The second case concerns the application of the methodology on Provence coalmines (South France). The application of the methodology shows such a coupling can be an efficient way for detecting areas subjected to rockburst hazard. This is also a powerful tool for assisting the planning of underground workings in complex geological and mining conditions. The coupling of geotechnical investigations (numerical modelling, in-situ stress measurements) and seismic analysis are strongly recommended.