Geophysical methods promulgate dam safety:
A dam is the foundation structure of a country that provides controlled and systematic flow of water for electricity production, to different channels of irrigation and useful resource utilization with many other factors to support life and its creatures.
Constructing a dam takes years to materialize since it is a very gargantuan process and needs high safety reviews during the construction but more so, ensuring dam’s safety is not child’s play. Dam Safety Geophysics come into force to keep the huge dam system running without stress or strength loss.
To guarantee dam’s safety, the complex understanding of filtration flow of underground and seeping water development is warranted.
Why we need to require Dam Safety Geophysics?
Several non-invasive and NDT methods are performed to facilitate detection of water seepage, cracks, piping leaks, erosion or corrosion of equipment in dams.
Overtime, the It is the foundation of voids within a soil causes removal of material by seepage. This is called internal erosion and it is being one of the foremost causes of failure of earthfill dams worldwide. Internal erosion can endanger embankments and damages resulting from such can lead to very expensive outcomes.
It is efficacious to consider Geophysical analysis to initiate dam safety surveillance which is usually done by visual inspections and with limited instrumentation. But these methods are a passé and can aggravate the internal erosion if the method is not followed religiously without care. Hence, the use of non-intrusive geophysical techniques has become unavoidable because it facilitates early detection of anomalous seepage, piping, and internal erosion.
Review of these methods needs to be done under expert supervision through Parsan’s Dam Safety Geophysical Services because such gargantuan problems need only professional service providers with years of experience and knowledge in damconstruction and maintenance.
There are a host of geophysical methods to detect seepage in dams which Parsan undertakes according to situation necessity. These can include:
• Temperature measurement to measure seasonal temperature variations to locate areas of preferential seepage.
• Self-potential technique to check electrical potentials generated by water flowing through soil pores. It emanates SP signals that are of primary interest in dam seepage studies.
• Direct current resistivity. The method uses pairs of electrodes to inject current into the ground and measure the resulting electrical potential distribution to monitor temporal variations in electrical resistivity when soil condition is influenced by internal erosion.
• Seismic methods like refraction, reflectionand cross-hole methods checks the time required for seismic energy to flow from its source to a receiver. The length of the travel path is calculated for seismic activity of low seismic velocity.
Although there have been many geophysical methods to investigate seepage in dams but it can produce mixed results so to have geotechnical feasibility and clarity on dam safety geophysics, only reliable geophysical services must be accepted.