Confined flow into a tunnel during progressive drilling: an analytical solution.
A convolution integral is developed to evaluate transient, drilling speed-dependent discharge rates into a tunnel gradually excavated in a homogeneous infinite aquifer. Comparison with the classical instantaneous-drilling evaluation commonly used in practice reveals drastically reduced early-time discharge rates, higher maximum rates, and similar long-term rates. Dimensionless-type curves are provided to help assess total discharge sensitivity to drilling time and predict safer maximum flow rates.
Perrochet
Pierre
P
Centre of Hydrogeology, University of Neuchâtel, Switzerland. pierre.perrochet@unine.ch
D008962:Models, Theoretical; D014872:Water Movements; D014881:Water Supply