CCI Foundation & Soil Analysis 2

Question 1

A soil sample has a liquid limit of 45 and a plastic limit of 20. What is the plasticity index?

Accepted Answer

25

Answer

Plasticity index (PI) = Liquid Limit − Plastic Limit = 45 − 20 = 25.

Question 2

Which field test is commonly used to estimate the in-situ undrained shear strength of cohesive soils?

Accepted Answer

Vane shear test

Answer

The field vane shear test directly measures undrained shear strength in soft to medium cohesive soils.

Question 3

A mat (raft) foundation is most appropriate when:

Accepted Answer

Individual footings would cover more than half the building area

Answer

When individual footings would overlap or cover more than 50% of the plan area, a mat foundation is more economical and effective.

Question 4

Which soil classification group under USCS is described as 'poorly graded gravel with little or no fines'?

Accepted Answer

GP

Answer

GP (Poorly Graded Gravel) has a wide range of particle sizes missing, resulting in a poor gradation curve.

Question 5

During pile driving, a 'set' refers to:

Accepted Answer

Penetration per blow at final driving

Answer

Set is the permanent penetration of a pile per blow measured at final driving, used in pile driving formulas to estimate capacity.

(CCI) Certified Construction Inspector Practice Test