Tunnel Drainage Management

Diverse deposits (calcium carbonate precipitates, iron ochre, bacterial biomass) from critical groundwater and water interacting with the tunnel structure (contact with concrete/building materials) pose a challenge to the smooth operation and maintenance of railway and road tunnels. The mineral and organic deposits (various calcium carbonates, iron [hydr]oxides, biofilms) block various and sometimes inaccessible components of the drainage system and thus prevent continuous tunnel drainage. Building materials can also be adversely affected by locally occurring physicochemical gradients and processes (material alteration, concrete attack, corrosion). The expertise covers the planning, construction, and operational phases of the infrastructure equally.

Customized solutions

The objective of Tunnel Drainage Management (TDM) is to develop a specific understanding of the processes involved in each tunnel and to devise customized solution strategies. This is based primarily on data-driven evaluation and optimization of the tunnel drainage system and its maintenance.

Each tunnel is characterized by its individual and interacting natural and technical conditions. These include geology and hydrology, water chemistry and air exchange, construction variants, building materials and flow geometries, local microbiology, and scaling potential. The variable conditions affect existing materials and emerging deposits.

TDM concerns both design and operational measures and is structured in modules that can be activated as needed to the extent required. The approach can be integrated into geotechnical planning and execution, into the process of geological tunnel documentation, or into the repair of a tunnel structure.

In particular, TDM also includes new monitoring concepts for hydrochemistry (drainage water, active substances) and solids (deposits, building materials) in combination with hydrogeochemical modeling (quantification). Various types of hardness stabilization measures can be specifically implemented at defined key points in the drainage system, i.e., optimization in terms of effectiveness, environmental compatibility, cleaning requirements, and expenses. For example, hardness stabilizers against deposits (ecologically harmless active substances – “green inhibitors”) are measured and optimized in terms of their active substance concentration and distribution in drainage water (e.g. using mobile fluorescence measurement).

TDM is carried out in cooperation with the Institute of Applied Geosciences at Graz University of Technology and the Geotechnical Engineering (Tunnel Planning) department at GC and is based largely on GEOCONSULT's interdisciplinary range of services and broad expertise.