...Indeed, Allah will not change the condition of a people until they change what is in themselves... Surah Ar-Rad 13:11 The Holy Quraan
Mentioned below are the various factors of soils and ground conditions that would affect the depth of the foundation.
Generally, the foundation is penetrated down to a minimum depth of 0.5m when considered below the natural ground level. If the ground site is a filled-up type, the penetration must go beyond the depth of fill or other methods given that special precautions are taken. In cases, where we need to have the foundation at a higher level, we determine the difference between the base of the foundation and the level of the excavation, which is filled up by
Below mentioned are recommendations for foundation construction under different ground conditions and soil types.
While constructing the foundation on a ground with slope, the distance from the edge of the footing to the ground surface as shown in figure-1 below is taken as:
As shown in the figure below, a line drawn at an angle of 30 degrees with the footing base must be parallel to the slope of the ground i.e. these lines must not intersect with each other.
Fig.1: Foundation on sloping ground
When a new footing has to be constructed near to an old footing, the width of the wider footing (w) is taken. The distance maintained during the construction of new footing with the old one is this width ‘w’. Based on the severity of the project, analysis of the bearing capacities and the settlement can be performed.
The figure-2 below shows the construction of footing at different levels on granular soils. As shown in figure, while constructing the footing at different level, it is recommended that the line joining the lower adjacent edges of the footing must not have a slope that is steeper than ½ (1 vertical to 2 horizontal).
Fig.2: Foundation on granular soils
While constructing footing at different levels over clayey soil, the line drawn between the adjacent edges of the footing as shown in figure-3 below must not be steeper than ½ ( One vertical and 2 horizontal).
Fig.3: Foundation on clayey soils