Building Construction
In the method of tube boring of soil investigation, the following is essential:

The tube is raised and lowered by 4 thick rope moving over a pulley suspended on a tripod stand
A flap valve at the bottom of tube is provided to extract the soil sample
A tube of about 2 meters length and 20 cm diameter with a cutting edge
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Building Construction
During percussion drilling

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Ground water observations are hindered due to entry of the slurry in the soil below the bottom of the hole
The soil to a considerable depth below the bottom of the hole gets disturbed
Caving or mixing of strata are caused in soft soils or cohesion-less soils

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