Estimating Deformation Modulus and Bearing Capacity of Deep Soils from Dynamic Penetration Test

Table 8

Correction factors for DPT blow counts (N₁₂₀) in the Chinese Code (GB50021-2001).

Rod length, L (m)	Measured blow count, N120
	1	3	5	7	9	10	15	20	25	30	35	40
1	1	1	1	1	1	1	1	1	1	1	1	1
2	0.96	0.92	0.91	0.9	0.9	0.9	0.9	0.89	0.89	0.88	0.88	0.88
3	0.94	0.88	0.86	0.85	0.84	0.84	0.84	0.83	0.82	0.82	0.81	0.81
5	0.92	0.82	0.79	0.78	0.77	0.77	0.76	0.75	0.74	0.73	0.72	0.72
7	0.9	0.78	0.75	0.74	0.73	0.72	0.71	0.7	0.68	0.68	0.67	0.66
9	0.88	0.75	0.72	0.7	0.69	0.68	0.67	0.66	0.64	0.63	0.62	0.62
11	0.87	0.73	0.69	0.67	0.66	0.66	0.64	0.62	0.61	0.6	0.59	0.58
13	0.86	0.71	0.67	0.65	0.64	0.63	0.61	0.6	0.58	0.57	0.56	0.55
15	0.86	0.69	0.65	0.63	0.62	0.61	0.59	0.58	0.56	0.55	0.54	0.53
17	0.85	0.68	0.63	0.61	0.6	0.6	0.57	0.56	0.54	0.53	0.52	0.5
19	0.84	0.66	0.62	0.6	0.58	0.58	0.56	0.54	0.52	0.51	0.5	0.48