The purpose of dam foundation drain

The purpose of dam foundation drainage is to reduce the seepage pressure of dam foundation surface by removing seepage.Drainage scope of dam foundation: a row of main drainage holes is generally set for foundation drainage. For the foundation with good geological conditions, the drainage effect shall be fully utilized, and 1-2 rows of auxiliary drainage holes can be set on the middle dam.Location and direction of drainage hole: the main drainage hole is set at the downstream of the anti-seepage curtain, and the auxiliary drainage hole can be set in the longitudinal drainage gallery of the foundation. On the surface of the dam foundation, the distance between the main drainage hole and the curtain grouting hole is 2m. The direction of the main drain hole inclines to the downstream, and the included angle of the valence is 15 °.The depth of the main drain hole is the depth of the curtain tank slurry Zero point five Times, i.e. 15m, the depth of auxiliary drain hole is 8m.Spacing of drainage holes: the spacing of main drainage holes is 3M, and the spacing of auxiliary drainage holes is 5m. Set a row along the dam axis.Hole diameter of drain hole: 130mm for main drain hole and 70mm for auxiliary drain hole.