The test pit should be at least five times wider than the test plate. The test plate is made to rest in a depression in the center of the pit equal to the size of the test plate and the bottom of which will correspond to the actual foundation level. The depth of the hole shall be such that the ratio of the depth to the width of the filled space is equal to the actual foundation. The thickness of the test plate is 2.5 cm and their sizes for different soils are as follows.
- Clayey soils, sandy and silty soils – size, 60 cm square
- Gravelly and dense sandy soils – size, 30 cm square
Larger sizes up to 75 cm square can be used depending upon practical
considerations.
The test plate should be machined on the sides and edges. The sides of the pit are lined with wooden sheeting if the soil is soft. The test plate shall be bedded to the soil by plaster of paris, aluminous cement slurry or fine sand. At the start of the test, the platform will be preloaded with a load of 0.7 kg/cm2 and released.
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