Standard Penetration Test

Standard Penetration Tests (SPT) were carried out to provide an indication of the density and/or

consistency of the ground and to obtain disturbed samples for visual inspection and laboratory testing and

classification. The results of the tests were given on the boring logs in Appendix A2 and were expressed

as an N value. The N value is defined as the blow-count for 12"(300 mm) penetration recorded after the

seating drive of 150 mm. In the case of premature refusal conditions, the number of blows for a recorded

penetration (including the seating drive) was noted.

During SPT test, the rope-and-pulley (R-P) method was used. This consisted of a hollow cylindrical mass

sliding over a steel rod. It is operated by lifting the mass with a rope over a cat head. At the instant the

mass reached the required height (760 mm), the mass is released automatically driving the split spoon into

the soil. Disturbed samples collected from the split-spoon sampler during Standard Penetration Test were

visually inspected before storing in a polyethylene zipper bag for laboratory testing. The test includes

dropping of hammer weighing 140 lbs (63.5kg) and falling freely over a constant height of 30” (76 cm)

along the drilled pipe in order to drive the sampler attached at the end of the same.