Table 2.

Experimental variables.

No.	Specimen Name	1st Con’c	2nd Con’c	Tamping Condition	Delay
1	NN-0	30	-	-	0
2	NN-15	30	30	×	15
3	NN-30	30	30	×	30
4	NN-60	30	30	×	60
5	TN-15	30	30	○	15
6	TN-30	30	30	○	30
7	TN-60	30	30	○	60
8	NU-0	180	-	-	0
9	NU-15	180	180	×	15
10	NU-30	180	180	×	30
11	NU-60	180	180	×	60
12	TU-15	180	180	○	15
13	TU-30	180	180	○	30
14	TU-60	180	180	○	60