DESIGN OF IMPERVIOUS FLOOR OF THE WEIR FOR SUB-SURFACE FLOW

  • Khanki weir failed in 1895. An expert’s committee under the Chairmanship of Lt. Col.
  • Caliborn, then Principal of Thomson College, Roorkee was set up to investigate the causes of failure of this weir, which was founded on sandy soil.
  • The committee confirmed Darcy’s law of seepage through sandy soils for low heads.
  • Heads are generally low in the case of weirs.
  • Later Mr. W.G. Bligh put forward

Fig. 15.4. Creep length by Bligh’s theory.

  • his own theory know by his name “Bligh’s creep theory” for sub-surface flows.
  • Later on Mr. Lane put forward is own theory in 1932 after having analyse a large number of dams.
  • This theory is know ‘Lane’s weight creep theory’.
  • A most elaborate scientific study base on facts was later carried out in 1936 by Pavlovsky and A.N. Khosla.
  • This theory is know “Khosla theory of Mr. Khosla carrie out most of his investigations in Punjab.
  • He publish the results of his analysis in Publication No. 12 of Central Board of Irrigation and Power, New Delhi.
  • Bligh’s creep theory, Lane’s weighted creep theory, and Khosla’s creep theories, are being explained in details one after the other.