Effect of size and unit weight of materials in bank protection

Abstract

A study to determine the suitability of a lighter material, such as 'burnt clay lump' which is can be made available localy, to replace stone in bank protection work was taken up. The effect of size and unit weight of materials in bank protection was studied in laboratory in a straight channel using cubical blocks made of sand-cement morter and brick. Saturated sand-cement bJ.ock had a specific gravity of 2.68 resembleming that of stone and brick blocks had a specific gravity of 2.18. Critical velocity at faiJ.ure of the blocks used as bank protective material was determined on four different side slopes. The volume of blocks was found to vary with the velocity at failure as the 6th and 7th power for sand-cement blocks and brick blocks respectively. The weight of blo.cks was found to vary with the velocity at failure as the 4.75th and 5.5th power for sand cement blocks and brick blocks respectively. It was observed that interlocking of the blocks and the waves in the channel are also major factors in the determination of proper size. of bank protective materials. It was also concluded that on a flatter side slope blocks of much less weight are required.