Activity : Deep Dynamic Compaction

A construction site is a landfill area consists of thin top layer of fine grained soil underlain by a thick layer of clayey silt

with varying thickness between $5$ to $8$ m $.$ The total site area is about $25$ m by $60$ m $.$ The fill has a moderate to high

degree of saturation. The standard penetration tests were carried out prior to ground improvement work which

indicates the site ha SPT N$-$value at various chosen locations range between $6$ to $18$ with an average value of $9.$ If

dynamic compaction is used as a ground improvement technique, provide a preliminary design. To minimize the

generation of excess pore water pressure multiple pass construction maybe used. Use a tamper weight of $20$ tons with

both tamper diameter and height as $1\mathrm{.}5$ m $.$ Also check for suitability of the method based on the allowable vibration

$($PPV$)$ when one side of the site exists a residential area at a distance of $20$ m and other side a commercial area at a

distance of $10$ m $.$