Excavation as per drawing:
Excavation is the first step in the Foundation process. It involves digging 3.5 feet high x 1.5 feet wide trenches where the main walls of the house would come up. A 7 course foundation wall (including multiple layers of sand, cement, gelly & stones) is layed and that forms the foundation wall 3 Feet high and 18 inch wide. The topmost course forms the ground floor surface and is called the "Plinth" Level.
Challenges:
- The level of the South-West side of the plot turned out to be 1.5 Feet lower than the rest of the plot. Due to this the foundation wall on the S-W side was 1. 5 higher than the rest of the sides. This is done to avoid sloping foundation bed.
- Due to the slope on the South-West side we encounted severe water logging due to the rain water seepage underneath. Digging of foundation trenches in water-logged sites poses a great problem. There are varous methods of dealing with the situation which depend upon the depth of excavation, depth of water table and many other factors. In this case the engineer decided to follow a process called consilidation of soil. The method involves pumping out the water quickly and then converting the soft water-logged soil into a semi-solid mass by forcing silicates (sand) into the soil. This method is generally adopted in water-logged portions for small work.
