Local roads in Poland, built for the most part in the previous economic system, are mostly unsuited to the ever-increasing traffic load, often built on a low-load organic substrate and need to be renovated. Linear objects are most often characterized by a significant variability in groundwater conditions in their area. The economical and safe design of the rebuild of a road structure often entails the need to implement ground improvement design of the low-bearing soil substrate, but areas of improvement should be adapted to the occurrence zones of low-bearing soil. The article presents a case study of the district road, for which ground and water conditions were recognized and organic soil were found. In addition to the rebuilding of the road structure to fulfill the requirements of the current traffic load and repairing the culverts, the reconstruction also included the ground improvement. The authors reviewed the types of road categories according to the admissible traffic loads (KR), the most important and commonly used methods of ground improvement, discussed the characteristics of the Benkelmann beam deflection method, proposed a design solution adapted to the existing conditions in the substrate and, after implementing it, presented the results of the deflection of the road before and after the reconstruction and soil improvement.

The landslide is located in Wronki. It covers the southern side on the bank of the Warta River and occupy an area of 500 m in length. The landslide was once again activated on August 22-23, 2018, causing numerous failures. The Warta River slope in the area of mass movements is built by non-construction embankments, under which the Poznan Miocene–Pliocene of quasi-layered structure lie. There are horizontal interlayers of sandy silts in these clays. The Warta drains water from a large area, and the runoff takes place mainly on the roof of clays. The slide surface of the landslide was precisely the roof of the Poznan clays. Bearing in mind the properties of the Poznan clays, such as relaxation, block disintegration, expansiveness features, the following were considered the direct causes of the failure: heavy rainfall that occurred after a drought, loading of the slope with indiscriminate cubature buildings, construction of a linear sewage system and periodically repeated vibrations caused by the implementation of neighboring investments. In order to identify the area, test boreholes were made, samples were taken for laboratory tests, and geodetic measurements were taken. Based on the obtained results, slope stability calculations were made and a measurement network was developed for systematic monitoring of geodetic displacements of control points. It was recommended to perform drainage to drain the slope and side of the Warta River, plant bushes, and make changes to the land development plan in order to prohibit further development of the area in the endangered zone.