Hauenstein road Trimbach / Hauenstein-Ifenthal: protective structures and rock protection

Rock stabilisation measures are currently being carried out along the Hauensteinstrasse in the municipalities of Trimbach and Hauenstein-Ifenthal (SO). The work is being carried out on behalf of the Canton of Solothurn, represented by the Office of Transport and Civil Engineering. In the project area, an above-average number of rockfalls were detected in a section of about 300 m above the "Rankbrünneli". In this section, the rock faces on the slope side come relatively close to the road and the slope flanks are very steep. 
In the course of a hazard analysis and risk assessment, the existing rock bands and slopes were evaluated by Louis Ingenieurgeologie Gmbh and, based on this, structural measures were planned and are now being implemented. The project aims to significantly reduce the risk for road users compared to the current situation and to achieve a reasonable availability of the transport mode. 
The embankment measures planned by IUB Engineering AG, which have been under construction since June 2023, are being carried out in impassable and correspondingly exposed terrain. In order to ensure work and traffic safety, preliminary rock cleaning work and temporary safety measures were carried out. In the first phase of the rock stabilisation sub-project, the danger to the road and road users was permanently eliminated by removing a fissured rock head. In addition, a rock slab that is in danger of tipping over and a rock wedge that is in danger of falling will be secured with individual anchors. Possible falls from the rock slab in the immediate vicinity of the road are prevented by an anchored ground net. 
In a second phase, two rockfall protection structures (250 kJ) and the protection of a rock section by means of a ground net will be constructed in the protection structures sub-project. The entire construction work will be carried out by the company Gasser Felstechnik AG until the targeted end of construction in September 2023.