2:00 ull LTE O ( Sam TCVD3682 Soil Mechanics - Assi... Question 3 Soil Compaction a) What are the factors that influence compaction of soil? b) In order to solve the problems of traffic jam through Town P, an embankment of 5 m high and 2 km long is proposed to be constructed to provide the roadway in a low land area. The embankment has a slope of 1 horizontal to 2 vertical (1H: 2V) on both sides and must be 12 m wide on its crown to provide 4 lanes. During the construction of the embankment, the selected borrow soil fill material has to be compacted at its maximum dry unit weight. 12 m- 5 m Cross section of the embankment The results of standard proctor tests conducted on the fill material during the preliminary investigation are as follows: Bulk density (kg/m³) 1840 2050 2160 2190 2180 2150 Water content (%) 6.2 8.0 9.3 10.2 12.1 13.6 i. Plot the compaction curve of the soil material. ii. Obtain the maximum dry unit weight with its corresponding water content and degree of saturation given that the specific gravity of the soil, Gs is 2.67. iii. On the same graph, plot the curve for 0% air voids and 5% air voids. 2 Hint: Use the formula below for moisture contents from 8% - 16% with intervals of 2%. Formula; G,Yw 100G,m+1 A Ya=(1- A: air voids content, m: moisture content. iv. Determine the dry density for a 95% relative compaction and obtain the range of moisture contents required to achieve this level of compaction. c) The in-situ moisture content of a soil at a borrow area is 16% and its bulk unit weight is 17.3 kN/m³. The specific gravity of the soil is 2.72. The soil is to be excavated and transported to a construction site for use in a compacted fill. i. If the specifications require the soil to be compacted to a dry unit weight of 18.1 kN/m³ at the same moisture content of 16%, how many cubic meters of soil from the excavation is needed to produce 2000 m³ of compacted fill? ii. What are the void ratio and degree of saturation of the compacted soil? iii. If a dump truck can carry 20 tons of soil in a given trip, how many trips are required to transport the soil to the construction site? - END -