Monitoring and Assessment of Remedial Measures in Closed Open Cast Mine

The excavated open cast mine Chabarovice, particularly the part of it with local name Rabenov, has been investigated and monitored by the Czech Technical University since 1998 because of problems connected with different types of instabilities. Complicated geotechnical conditions, extreme heterogeneity and artesian ground water of the origin site together with the conditions modified by open cast mining were the main reasons of land sliding. Stability analyses made by the Department of Geotechnics were focused on final slopes of the mine together with the supporting waste dump and they were based on analyses of 3-D deformation monitoring in instrumented boreholes and pore water pressure sensing. The Department has contributed to development of several types of remedial measures as drainage works, re-shaping, stabilizing embankment assessment, discontinuous anchored pile wall. The group of experts of the Department was asked to provide risk analysis of the final version of the design of the measures of the last but not stable Rabenov part of the mine. The results of the monitoring with results of analyses will be presented in the paper. Development of displacements on the site demonstrated partly different behavior than expected at the design stage and it approved concerns stated in our risk analysis. These events are described and discussed in the paper. There were successfully tested different applications of fiber optics deformation monitoring developed in before research and development projects, there. Continuous high resolution fiber optic monitoring system was modified for a new research focused on a group of churches in eastern Bohemia.