Question

Excavation may be classified by type of material- Earth excavation ________ excavation, rock excavation, muck excavation, unclassified excavation.

(a) bottom soil

(b) sub-soil

(c) topsoil

(d) surface soil

The question was posed to me in class test.

Question is taken from Earthwork, Concrete and R.C.C. work topic in section Rules and Methods of Measurement of Civil Engineering Drawing

Answer 1

Right answer is (c) topsoil

Explanation: Topsoil is the upper, outermost layer of soil, usually the top 2 inches (5.1 cm) to 8 inches (20 cm). It has the highest concentration of organic matter and microorganisms and is where most of the Earth’s biological soil activity occurs. Four elements constitute the composition of soil. Those elements are mineral particles, organic matter, water, and air. The volume of top soil consists of 50 to 80% of these particles which form the skeletal structure of most soils.