Behaviour of clay with double porosity with respect to high waste tips

Extensive opencast mining of brown coal has caused significant changes in landscape by forming deep voids and high waste tips. The tips are well known to have problems of stability and large differential settlements due to the behaviour of stockpiled clayey soil. Investigation of stockpiled clay was based on laboratory testing on typical material from opencast mines. The clay was crushed and sorted to obtain different collections of particles. The particle sets were tested to measure 1-D and 3-D compression, volume changes, shear strength by triaxial tests under relevant stress states and arbitrary conditions of saturation. Selected results from the tests are presented and discussed in the article. An example of deformation development and stability evaluation of a waste tip is presented from the point view of relevant input data and requirements for monitoring in order to contrast engineering and scientific approaches.

• 1 INTRODUCTION

• 2 LABORATORY INVESTIGATION

• 3 RESULTS OF LABORATORY TESTS

• 4 APPLICATION OF RESULTS

• 5 ACKNOWLEDGEMENTS

• 6 REFERENCES