An Investigation of In-Situ Ground Conditions Through the Application of Advanced Shaft Wall Monitoring Tools
Sven Bock, DMT GmbH & Co. KG; Juergen Franz, DMT GmbH & Co. KG; Martin Weber, DMT GmbH & Co. KG; Nikolai Hentrich, DMT GmbH & Co. KG; Diego Sancho Calderon, DMT Geosciences Ltd.
At the start of a new shaft project a specific number of ground investigations is performed. In most cases the investigations are based on the analysis of rock and soil probes obtained from boreholes. However, in practice such analysis performed on a single core often leads to the different results when conducted by various experts or companies. Such discrepancy in core analysis influences the further rock mass assessment and design assumptions. Furthermore, it is not uncommon that the ground conditions during shaft sinking may differ from the designed ones, which has a great impact on the estimated stress and strain state of the shaft lining. Therefore it is extremely important to use tools allowing minimization of such discrepancy and to include into the shaft design a sufficient monitoring system, allowing to control all important phenomena not only during shaft sinking, but also during lifetime of the shaft. The paper presents an overview of existing monitoring techniques and discuss required future work in order to further improve not only the underground works during shaft sinking, but also the shaft lining design methodology.
ground conditions, shaft sinking, shaft design, monitoring