A 5 Excavating And Grading Practice Exam

A-5 EXCAVATING AND

GRADING PRACTICE

EXAM Question 1: A roadway subgrade is designed at elevation 102.40 ft. A grade stake at the same station reads 104.15 ft. How much cut is required to reach subgrade?

Choices:

1) 1.25 ft 2) 1.50 ft 3) 1.75 ft 4) 2.55 ft

Correct Answer: 1.75 ft

Explanation: Required cut equals existing elevation minus design elevation: 104.15 - 102.40 = 1.75 ft.Page 1

Question 2: Which soil condition generally produces the greatest risk of trench-wall collapse?

Choices:

1) Dense well-graded gravel above the water table 2) Previously disturbed soil with seepage 3) Cemented soil that can be excavated vertically 4) Sound stable rock

Correct Answer: Previously disturbed soil with seepage

Explanation: Previously disturbed soil with water seepage has reduced strength and is more prone to sloughing or collapse than dense undisturbed material or stable rock.Question 3: A compacted �ll area measures 120 ft by 80 ft and must be raised an average of 1.5 ft. Approximately how many compacted cubic yards of �ll are required?

Choices:

1) 400 cu yd 2) 480 cu yd 3) 533 cu yd 4) 720 cu yd

Correct Answer: 533 cu yd

Explanation: Volume is 120 x 80 x 1.5 = 14,400 cubic feet. Dividing by 27 gives about 533 cubic yards of compacted �ll.Page 2

Question 4: What is the primary purpose of moisture conditioning a soil before

compaction?

Choices:

1) To eliminate the need for density testing 2) To bring the soil near a moisture content at which speci�ed density can be achieved e�ciently 3) To increase the soil's organic content 4) To prevent any future settlement regardless of soil type Correct Answer: To bring the soil near a moisture content at which speci�ed density can be achieved e�ciently Explanation: Compaction is most e�cient when soil moisture is near the value associated with maximum dry density for the chosen compactive e�ort.Question 5: Which machine is generally most e�cient for pushing soil over relatively short haul distances on a grading project?

Choices:

1) Crawler dozer 2) Tower crane 3) Truck-mounted auger 4) Concrete pump

Correct Answer: Crawler dozer

Explanation: A crawler dozer is designed to cut, push, spread, and rough-grade earth e�ciently over short distances.Page 3