Groundwater has the potential to result in significant geotechnical issues for development of infrastructure projects such as:
The presence of water within a rock, engineered or residual soil excavation batter can have a detrimental effect on the stability of that structure. This is principally due to the action that increased or elevated pore water pressure can have on the strength of the rock or soil. Groundwater occurs within pores spaces, fractures, bedding plains and other discontinuities within the rock or soil where these features are below the saturated groundwater surface or water table.
The implications of increased pore water pressures in a batter slope can result in slope failure. In an open cut or underground mine operation, excavation, tailings dam embankment or waste dump, this can impact on geotechnical performance, having a financial impact on the project and more importantly create a safety threat for mine workers and the general public.
Hydrogeological studies are therefore intrinsic for addressing geotechnical issues relating to slope stability. A hydrogeological assessment must define the existing groundwater conditions, describe how groundwater can be managed to enable design to minimise slope stability issues, and provide a safe working environment.
Recognising the significance of groundwater in slope stability, investigative techniques applied to an open cut mining situation can include, but are not limited to;
How the results from these investigation methods allow for design of appropriate management systems are presented, showing how dewatering for slope depressurisation options can achieve acceptable outcomes for protecting the asset as well as the environment, and particularly human safety.