Advanced Topics in Tunnel Drainage Research.
Expert-defined terms from the Advanced Certificate in Tunnel Drainage Engineering course at London School of Business and Administration. Free to read, free to share, paired with a globally recognised certification pathway.
Advanced Topics in Tunnel Drainage Research #
a series of specialized subjects focused on the study and management of water flow in tunnels and underground structures. This glossary provides essential terms, concepts, and acronyms related to this field.
Advection #
the process of transporting a substance (like water or heat) through a fluid (like air or water) due to the fluid's motion. In tunnel drainage, advection plays a crucial role in the movement of groundwater and contaminants.
Aquifer #
a geological formation that contains and transmits significant quantities of water. Aquifers can be confined (under pressure) or unconfined (exposed to atmospheric pressure). They are essential for tunnel drainage, as they can affect water inflow rates and groundwater levels.
Base drain #
a system of pipes, channels, or ditches designed to collect and remove water from the base of a tunnel. Proper base drain design is crucial for maintaining structural stability and preventing water damage.
Bedrock #
the solid rock that lies beneath soil, sediment, or other loose material. Bedrock properties, such as permeability and fractures, can significantly impact tunnel drainage.
Capillarity #
the ability of water to rise or be drawn into small spaces, like the pores between soil particles. Capillarity can affect groundwater flow and water inflow rates in tunnels.
Confining layer #
a geological layer with low permeability that overlies or underlies an aquifer, restricting the flow of water in or out of the aquifer. Confining layers can impact groundwater levels and water inflow in tunnels.
Deformation modulus #
a measure of a material's (such as rock or soil) resistance to deformation under an applied load. This value is essential for estimating tunnel stability and water inflow.
Darcy's law #
an equation that describes the flow rate of a fluid through a porous medium in terms of the hydraulic gradient and permeability. Darcy's law is widely used in tunnel drainage to estimate water flow and groundwater levels.
Drainage adit #
a horizontal or nearly horizontal tunnel that intercepts and drains groundwater from the surrounding rock, reducing water inflow into the main tunnel.
Effective stress #
the stress experienced by a soil or rock particle due to the weight of overlying materials, minus the pore pressure exerted by any interstitial fluids. Effective stress is essential for understanding tunnel stability and water inflow.
Epicenter #
the point on the Earth's surface directly above the focus (hypocenter) of an earthquake. Earthquakes can cause ground movement, potentially affecting tunnel drainage and stability.
Filter cake #
a layer of fine particles that accumulates on the surface of a filter medium during a filtration process. In tunnel drainage, filter cakes can form in drainage systems and affect water flow.
Fluid mechanics #
the study of how fluids (liquids and gases) behave under various conditions, including their motion, interaction with surfaces, and transfer of energy. Fluid mechanics is crucial for understanding water flow in tunnel drainage systems.
Gauge pressure #
the pressure exerted by a fluid relative to the ambient atmospheric pressure. Gauge pressure is used to quantify the pressure in tunnel drainage systems.
Geological mapping #
the process of creating detailed maps of geological formations, including the identification of rock types, structures, and hydrogeological features. Geological mapping is essential for predicting and managing tunnel drainage issues.
Geophysical survey #
a non-invasive method for investigating the subsurface using various physical principles, such as seismic, electrical, or electromagnetic measurements. Geophysical surveys can help identify groundwater flow patterns, bedrock structures, and potential drainage issues in tunnel construction.
Groundwater level #
the height of the water table or the potentiometric surface in an aquifer. Changes in groundwater levels can affect water inflow rates in tunnels.
Groundwater recharge #
the process by which water from precipitation, surface water bodies, or irrigation infiltrates into the ground and becomes part of the groundwater system. Groundwater recharge is an essential factor in tunnel drainage, as it can affect groundwater levels and water inflow.
Head (hydraulic) #
the height to which water will rise in a vertical tube due to the pressure exerted by the water. Hydraulic head is used in Darcy's law to calculate water flow rates in porous media.
Hydraulic conductivity #
a measure of a porous medium's ability to transmit water under a hydraulic gradient. Hydraulic conductivity is a key parameter in Darcy's law and is used to estimate water flow and groundwater levels in tunnel drainage systems.
Hydraulic gradient #
the difference in hydraulic head (pressure) between two points in a fluid, divided by the distance between those points. Hydraulic gradient is a fundamental concept in fluid mechanics and is used to calculate water flow rates in tunnel drainage systems.
Hydrogeology #
the study of the distribution, movement, and properties of groundwater in geological formations. Hydrogeology is an essential discipline in tunnel drainage research and engineering.
Hydrostatic pressure #
the pressure exerted by a column of water due to gravity. Hydrostatic pressure is a key factor in tunnel drainage, as it can affect water inflow rates and groundwater levels.
Inflow rate #
the volume of water entering a tunnel or drainage system per unit time. Inflow rate is an essential parameter in tunnel drainage design and management.
In #
situ testing: the process of evaluating the properties of soils or rocks in their natural (in-situ) state, rather than in a laboratory setting. In-situ testing is crucial for obtaining accurate data on tunnel drainage-related factors such as permeability, deformation modulus, and effective stress.
Instrumentation #
the use of sensors, data loggers, and other monitoring devices to measure various parameters (like water pressure, movement, or strain) in tunnel drainage systems. Instrumentation is essential for understanding and managing tunnel drainage issues.
Interstitial water #
the water present in the pore spaces between soil or rock particles. Interstitial water is an important factor in tunnel drainage, as it can affect water inflow rates and groundwater levels.
Karst system #
a geological formation characterized by dissolution of soluble rocks, such as limestone or dolomite, leading to features like caves, sinkholes, and underground streams. Karst systems can pose significant challenges for tunnel drainage due to their complex hydrogeology and potential for rapid water flow.
Lugeon test #
an in-situ test used to measure the hydraulic conductivity (permeability) of rock formations by injecting water under pressure into a borehole and measuring the resulting water flow. Lugeon tests are commonly used in tunnel drainage to assess water inflow potential.
Percussion drilling #
a drilling method that uses repeated blows from a drill bit (or hammer) to break rock or soil, allowing for the removal of drill cuttings. Percussion drilling is often used in tunnel drainage to investigate subsurface conditions and install monitoring instruments.
Permeability #
a measure of a porous medium's ability to transmit fluids. Permeability is a fundamental parameter in tunnel drainage, as it affects water inflow rates and groundwater levels.
Piezometer #
a device used to measure the pressure or level of groundwater in an aquifer. Piezometers are essential instruments in tunnel drainage research and management.
Pore pressure #
the pressure exerted by water in the pore spaces between soil or rock particles. Pore pressure is an essential factor in understanding effective stress and tunnel drainage.
Poroelasticity #
the study of the deformation and stresses that occur in porous materials (like soils and rocks) when subjected to changes in fluid pressure or pore fluid content. Poroelasticity is an essential