Alkalinity is an important determination to the water treatment plant operator because some of the coagulants used to clarify water and prepare it for filtration required sufficient alkalinity to insure a proper reaction. The alkalinity may be increased by adding lime or NA2CO3. Excessive alkalinity may be however interfere with coagulants.

The structure used to retain or support the material/soil is called retaining structure. e,g retaining walls, which may be of RCC, brick or stone masonry or sheet piling etc.

It is strong in compression and weak in tension so no tension should be allowed in any part of the retaining wall, especially the base of the supporting wall. Earth embankments/slopes are commonly required on railways, roads, earth dams etc. The stability of these slopes must therefore be thoroughly analysed as their failure may lead to loss of human life as well as economic

Infinite Slope: The type of slope extending infinitely, or upto an extent whose boundaries are not well defined. For this type of slope the soil properties for all identical depths below the surface are same. In the making of natural slopes, thier is no contribution from our side.

Using volumes is not very convenient in most calculations. An alternative measure that is used is the voids ratio, e. This is defined as the ratio of the volume of voids, Vv to the volume of solids, Vs, that is A related quantity is the porosity, n, which is defined as ratio of the volume of voids to the total volume. The degree of saturation, S, has an important influence on