Figure 1
![Roberson soil behaviour type classification chart[7]](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647378f34e662f30ba53f813/j_sgem-2020-0002_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251020%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251020T112510Z&X-Amz-Expires=3600&X-Amz-Signature=ba8f6e3a0e8c33aebf3e1cc0b353b2f9581b50cccc142f4e3256adadf26c9769&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 2
![Roberson's soil behaviour type classification chart[11]](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647378f34e662f30ba53f813/j_sgem-2020-0002_fig_002.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251020%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251020T112510Z&X-Amz-Expires=3600&X-Amz-Signature=2bba2c2af4650587b8f44560a258287e7e4d73fe16df967d03b7bda48f3495bd&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 3
![The Ic thresholds showed on Roberson's soil behaviour type classification chart[8]](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647378f34e662f30ba53f813/j_sgem-2020-0002_fig_003.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251020%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251020T112510Z&X-Amz-Expires=3600&X-Amz-Signature=6140a56dc1f90da13c2ebc0effa27e65d941cfb9de3e1bc861d0af45e5183a2b&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 4
![Illustration of failure mechanism and impact zone for pile[13]](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647378f34e662f30ba53f813/j_sgem-2020-0002_fig_004.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251020%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251020T112510Z&X-Amz-Expires=3600&X-Amz-Signature=802fb3cf79624990de53f0667431d236a5dc68c669af0759fb943a8103ac2bf2&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 5
![The schema of the effect of thin layer and transition zone[2]](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647378f34e662f30ba53f813/j_sgem-2020-0002_fig_005.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251020%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251020T112510Z&X-Amz-Expires=3600&X-Amz-Signature=e3386ccc72c3574ef48f2dc7c6630f52aa3b43b6ed5f97e213a8ef243ae3ffab&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 6

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Figure 11

Numbers of subdivisions and corresponding Soil Behaviour Types[11]
SBT | Soil behaviour type |
---|---|
1 | Sensitive, fine grained |
2 | Organic soils: peats |
3 | Clays: silty clay to clay |
4 | Silt mixtures: clayey silt to silty clay |
5 | Sand mixtures: silty sand to sandy silt |
6 | Sand: clean sand to silty sand |
7 | Gravelly sand to dense sand |
8 | Very stiff sand to clayey sand |
9 | Very stiff, fine grained |
SBT index classification proposed by Robertson and Wride[8]
Classification | Soil behaviour type | Soil behaviour type index Ic |
---|---|---|
SBT2 | Organic soils: peats | Ic > 3.60 |
SBT3 | Clays: silty clay to clay | 2.95 ≤ Ic < 3.60 |
SBT4 | Silt mixtures: clayey silt to silty clay | 2.60 ≤ Ic < 2.95 |
SBT5 | Sand mixtures: silty sand to sandy silt | 2.05 ≤ Ic < =2.60 |
SBT6 | Sand: clean sand to silty sand | 1.31 ≤ Ic < =2.05 |
SBT7 | Gravelly sand to dense sand | Ic < 1.31 |
Numbers of subdivisions and corresponding Soil Behaviour Types[7]
SBT | Soil Behaviour Type |
---|---|
1 | Sensitive fine grained |
2 | Organic material |
3 | Clay |
4 | Silty clay to clay |
5 | Clayey silt to silty clay |
6 | Sandy silt to clayey silt |
7 | Silty sand to sandy silt |
8 | Sand to silty sand |
9 | Sand |
10 | Gravelly sand to sand |
11 | Very stiff fine grained |
12 | Sand to clayey sand |