Water inflow into a pit limited by a bulkhead

Abstract

In the practice of hydraulic engineering, one often encounters the following case of water inflow into a pit limited by a cofferdam. The pit is arranged in loose, practically homogeneous rocks, characterized by a constant filtration coefficient. Its bottom coincides with the aquiclude, the slope is determined by a certain slope coefficient m = ctg φ, constant along the entire height. The pit is limited by a cofferdam, composed of rocks, the filtration coefficient of which is very small compared to the filtration coefficient of the soils underlying the cofferdam. The cofferdam maintains a certain level in the upper pool. Water from the pool moves under the cofferdam and comes out onto the pit slope. In this case, in practice, the most common case is when, upon reaching the slope at point M, the underground flow is characterized as unconfined. At the same time, in the initial section of its movement under the cofferdam, the underground flow, limited from above by the base of the cofferdam and from below by the aquiclude, is under pressure.