Ground improvement methods for the construction of the federal road B 176 on a new elevated dump in the brown coal region of MIBRAG

摘要

The MIBRAG Company operates two surface mines in the region south of Leipzig in Germany. This is the reason why the existing B176 road needed to be relocated up to 1 km on a length of more than 5 km. This move will place the new road on almost 60 m recently placed landfill area. Different ground improvement techniques such as Controlled Modulus Columns (CMC), Dynamic compaction and Dynamic Replacement were used for the foundation of the bridge and the road depending on the soil conditions and settlement tolerance of the structure. Because of significant stability problems, 15 m deep "floating" stone columns are installed in the landfill. The design and the settlements were significantly optimized by the combination of the different soil improvement techniques. The settlement forecast based on DIN EN 4094-5 Menard pressuremeter results and finite elements calculations are validated with the results of inclinometer measurements under the largest 15-m-high and 70-m-wide embankment.