Open pit protection and foundation design – Aparthotel Žnjan
The construction of a new catering and tourism facility, the Aparthotel Žnjan, is planned in the southeastern part of the city of Split, in the seaside district of Žnjan. The new Aparthotel will cover 2,094 square meters and have 2 underground floors and 6 aboveground floors.
For the construction of the Aparthotel Žnjan, it is necessary to cut into the existing terrain using an open pit protection up to 25.0 m deep and to transfer the load to deeper and more favorable foundation soil layers in order to avoid differential settlements of the building.
We have carried out engineering-geological and geotechnical investigation and testing for the foundation design. These works included exploratory rotary drilling, engineering-geological mapping and determination of drilling cores, laboratory testing of samples from exploratory boreholes and processing data from previous investigation. The foundation of the building is planned by the execution of reinforced concrete drilled piles. Above the open pit, the execution of reinforced concrete retaining walls is planned for the purpose of forming the future plateau.
The open pit protection is divided into a total of 9 zones, where the boundaries of the zones are defined by the geotechnical characteristics of the location and the geometry of the Aparthotel.
A permanent vertical open pit protection on the part of the excavation within the flysch deposits consists of self-drilling anchors and shotcrete. On the part of the excavation inside the surface deposits consists of pile wall, geotechnical anchors and shotcrete.
For this project, the deep foundation of the building is planned with the construction of reinforced concrete drilled piles (D = 620.0 mm in diameter), which need to be built at a depth of at least 1.60 m within the rock mass.
During the excavation and the open pit protection, regular geotechnical supervision is necessary, as well as engineering geological mapping of the open pit and open pit movement monitoring.