The highway A143 is located near the city of Halle/Saale in Eastern Germany. 3 km of the southern section of this highway are located above abandoned and not properly backfilled room and pillar lignite mines as well as corresponding shafts and galleries. As a consequence of mining, cavities and loose zones are existing in the ground which lead to the occurrence of sinkholes.

Dynamic compaction by falling weights was carried out in the area of the new highway to destroy the existing cavities which on the short- or medium-term would have lead to sinkholes. Furthermore, the loose soil was planned to be compacted and homogenized down to greater depths.

The occurrence of sinkholes can however still not be outruled for the long-term. To prevent a sudden collapse of the pavement these sinkholes are planned to be bridged by a single-layer geosynthetic reinforcement, which was designed by geometrically non-linear 3D-FE-analyses.

One bridge and two pillars of an electricity line, which are also located in the area of potential sinkholes, were founded on bored piles. The piles were partly surrounded by a HDPE-membrane to reduce the negative skin friction which occurs in case of a sinkhole.

The northern section of the highway, which is currently under design is also partly located above abandoned mines. Because of the ground conditions and the greater depth of the old mines the ground in this section is planned to be improved by grouting.