Here in Kerala we have 3 to 4 types of soil. One is slime filled soil, sandy soil, then laterite etc. slime filled soil is more like a sponge with water content, when weight is applied, the water in the soil escapes resulting in the sinking of the building. That is why any building in slimy areas tend to sink. Next is the river side soil, where the tendency to sink exists but less compared to slimy soil. Then we have soil with greater percent of sand content, mainly found near sea or river side. On this, we can build a strong foundation, but the tendency to wash out during flushing of flood is strong. In certain other areas, we can see a mix of soils in various proportions. To understand the nature of the soil, a proper soil investigation is executed. Then we have laterite or rock soil, which enables to construct a strong foundation. We also have fertile soil, usually found in forest areas, which also has this sinking tendency.
Now let’s see how we can lay a big foundation economically. Whatever be the type of soil, for an economical viable foundation, we will have to reduce the weight of the building. Depending upon the nature of the soil, we will have to dig deep into the soil. For rocky or laterite, this can be avoided to a certain extend.
When does a building tilt?
This happens when the soil is a mix of 2 or more variants. In such cases the tendency of the building to tilt is higher. If a building has slimy soil in one area and sandy soil in another, possibility for that building to tilt is more. We do have technologies to rectify this. What all measures should be taken to avoid this? Soil investigation is the first and foremost thing to be done before heading for a foundation. This will enable us to understand about the type of soil under the foundation, and accordingly we can fix the strength of the foundation. Even RBI has prioritized soil investigation, before sanctioning loans for construction.
And so the first and the foremost step towards a strong building is soil investigation, which enables an economically feasible foundation