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=ASIA6AP2G7AKLJOKGJCJ%2F20260222%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260222T020921Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEO7%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDGV1LWNlbnRyYWwtMSJHMEUCICeI9JC4gcnZ6iWz3tH8A%2ByAKQ7BTabzCljAMZIGEIDIAiEAtFLKKVUUcUxMP%2BFqWRbl2185zjgLz%2FKFKXLmsgJ7DTIqxgUIt%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARACGgw5NjMxMzQyODk5NDAiDOvYeHKDCezhLliHjiqaBdWMP2nNbH5xtHXojzyPX7113hXw2CypHDASe6S3TgxSjArGZF1VEigzF4bkWzkvjC6eRXxGoP1xdtv2j32pQgpPPr03Er7Hlt4N%2BBGuLAa9ZyqN3msuvLeRx%2BIaw%2BkE8r9205Hw2ghrCoWASdruNdT%2BFVwEg185W6WWsOAfiF19VR2BNRfmKlpds0oRVN5A%2BlPFj%2FcQQCrLBJjF4pUcYtRMMfP5DWOSbzrnREfUVW2TnuJkMmMJ0kFFQBQiHKWaNvaOyWoyt3e73bD%2FgEPPSGlrnThNiP1%2B7uWnhYGfiuQcj0oYFuBPUVgriT0OyO8g7gMngQJK0Th3kuK4Mdhm%2FvMelxTVPQMzO6ShyClHX0vSuLpkQnblRkVPszcOPHfA59XvZWI6T%2BRZfjBEfPKu7X0cHLcbHGcjxtlCu3y1VY3mzP9zTyjOHbvfVC9SyCwZqbK%2Fc6td%2FM6pXULBYfappqq694HULwxsfDqpNj2ldC4IzLLYx0AdNad2AHRnSEtOaUW%2BFslpR0oXGfLUlFYSJ3xUbUdD%2Bv2I%2FW9YByDbxdzot0rf2YOZPQ7nJsW5AUoRT6ORFdfkoYlUB720hpsIdcri5kxfEU7yjpFWZ7W3QAkf6EYQbWPb%2BPqMkejh44z7E%2Fxzeg%2F5wr1UyJ5PqfuIxZXku%2FODpGbpqfy5EAGLj2zbUBjJvw%2BBHDAj1kLxsqu0nb%2BEwxJIIvtnjIt%2FvpUVRHmxFrmlwa67eLa9kvpwLshtWDHuCF9EKRRpXdDSHzG7aUwKe0jBSIBtuDye2ZXmXVIbP8uluJWbSosMeGg77mHfPUrOTmjW52r4ewgHJu4130PbrHq6TbvtgpdWnZPy0ZB%2B4Oy0yEBGZE5VHVeX0sP0cLrgNDs7nj6PBTDgyejMBjqxASsGKVx6mmM9cr6FHSwDOsVk90bpW0cOmI2IJ8%2BRpH9CWgbvuoO%2FXyL9h11Q9b4PxT5sE5k%2BnXD7Q6mU2R9BkJZEpxdoaulGlpYhkat4rS3GJtOEzMnyQqJ%2BiefBFnXNmKmU6Kv5mLbAH5yTVy%2F%2FdHx%2FTLAI0NYYRxW7%2BByMbrqagnHOOt9eZN%2BrObzO2XIxpvCjuBK6pI%2FmqJImpoBamqPjNzAKe1VSpyo35YEWxLAFIQ%3D%3D&X-Amz-Signature=e905265ccefcf1c19c2814db34d3889ee4313a38d56d09f1f20883761e9ef5f5&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=ASIA6AP2G7AKLJOKGJCJ%2F20260222%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260222T020921Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEO7%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDGV1LWNlbnRyYWwtMSJHMEUCICeI9JC4gcnZ6iWz3tH8A%2ByAKQ7BTabzCljAMZIGEIDIAiEAtFLKKVUUcUxMP%2BFqWRbl2185zjgLz%2FKFKXLmsgJ7DTIqxgUIt%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARACGgw5NjMxMzQyODk5NDAiDOvYeHKDCezhLliHjiqaBdWMP2nNbH5xtHXojzyPX7113hXw2CypHDASe6S3TgxSjArGZF1VEigzF4bkWzkvjC6eRXxGoP1xdtv2j32pQgpPPr03Er7Hlt4N%2BBGuLAa9ZyqN3msuvLeRx%2BIaw%2BkE8r9205Hw2ghrCoWASdruNdT%2BFVwEg185W6WWsOAfiF19VR2BNRfmKlpds0oRVN5A%2BlPFj%2FcQQCrLBJjF4pUcYtRMMfP5DWOSbzrnREfUVW2TnuJkMmMJ0kFFQBQiHKWaNvaOyWoyt3e73bD%2FgEPPSGlrnThNiP1%2B7uWnhYGfiuQcj0oYFuBPUVgriT0OyO8g7gMngQJK0Th3kuK4Mdhm%2FvMelxTVPQMzO6ShyClHX0vSuLpkQnblRkVPszcOPHfA59XvZWI6T%2BRZfjBEfPKu7X0cHLcbHGcjxtlCu3y1VY3mzP9zTyjOHbvfVC9SyCwZqbK%2Fc6td%2FM6pXULBYfappqq694HULwxsfDqpNj2ldC4IzLLYx0AdNad2AHRnSEtOaUW%2BFslpR0oXGfLUlFYSJ3xUbUdD%2Bv2I%2FW9YByDbxdzot0rf2YOZPQ7nJsW5AUoRT6ORFdfkoYlUB720hpsIdcri5kxfEU7yjpFWZ7W3QAkf6EYQbWPb%2BPqMkejh44z7E%2Fxzeg%2F5wr1UyJ5PqfuIxZXku%2FODpGbpqfy5EAGLj2zbUBjJvw%2BBHDAj1kLxsqu0nb%2BEwxJIIvtnjIt%2FvpUVRHmxFrmlwa67eLa9kvpwLshtWDHuCF9EKRRpXdDSHzG7aUwKe0jBSIBtuDye2ZXmXVIbP8uluJWbSosMeGg77mHfPUrOTmjW52r4ewgHJu4130PbrHq6TbvtgpdWnZPy0ZB%2B4Oy0yEBGZE5VHVeX0sP0cLrgNDs7nj6PBTDgyejMBjqxASsGKVx6mmM9cr6FHSwDOsVk90bpW0cOmI2IJ8%2BRpH9CWgbvuoO%2FXyL9h11Q9b4PxT5sE5k%2BnXD7Q6mU2R9BkJZEpxdoaulGlpYhkat4rS3GJtOEzMnyQqJ%2BiefBFnXNmKmU6Kv5mLbAH5yTVy%2F%2FdHx%2FTLAI0NYYRxW7%2BByMbrqagnHOOt9eZN%2BrObzO2XIxpvCjuBK6pI%2FmqJImpoBamqPjNzAKe1VSpyo35YEWxLAFIQ%3D%3D&X-Amz-Signature=ac6413e3900b9e8b37327520672f1fda06de58b4e59d3d883c86a2b069975342&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=ASIA6AP2G7AKLJOKGJCJ%2F20260222%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260222T020921Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEO7%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDGV1LWNlbnRyYWwtMSJHMEUCICeI9JC4gcnZ6iWz3tH8A%2ByAKQ7BTabzCljAMZIGEIDIAiEAtFLKKVUUcUxMP%2BFqWRbl2185zjgLz%2FKFKXLmsgJ7DTIqxgUIt%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARACGgw5NjMxMzQyODk5NDAiDOvYeHKDCezhLliHjiqaBdWMP2nNbH5xtHXojzyPX7113hXw2CypHDASe6S3TgxSjArGZF1VEigzF4bkWzkvjC6eRXxGoP1xdtv2j32pQgpPPr03Er7Hlt4N%2BBGuLAa9ZyqN3msuvLeRx%2BIaw%2BkE8r9205Hw2ghrCoWASdruNdT%2BFVwEg185W6WWsOAfiF19VR2BNRfmKlpds0oRVN5A%2BlPFj%2FcQQCrLBJjF4pUcYtRMMfP5DWOSbzrnREfUVW2TnuJkMmMJ0kFFQBQiHKWaNvaOyWoyt3e73bD%2FgEPPSGlrnThNiP1%2B7uWnhYGfiuQcj0oYFuBPUVgriT0OyO8g7gMngQJK0Th3kuK4Mdhm%2FvMelxTVPQMzO6ShyClHX0vSuLpkQnblRkVPszcOPHfA59XvZWI6T%2BRZfjBEfPKu7X0cHLcbHGcjxtlCu3y1VY3mzP9zTyjOHbvfVC9SyCwZqbK%2Fc6td%2FM6pXULBYfappqq694HULwxsfDqpNj2ldC4IzLLYx0AdNad2AHRnSEtOaUW%2BFslpR0oXGfLUlFYSJ3xUbUdD%2Bv2I%2FW9YByDbxdzot0rf2YOZPQ7nJsW5AUoRT6ORFdfkoYlUB720hpsIdcri5kxfEU7yjpFWZ7W3QAkf6EYQbWPb%2BPqMkejh44z7E%2Fxzeg%2F5wr1UyJ5PqfuIxZXku%2FODpGbpqfy5EAGLj2zbUBjJvw%2BBHDAj1kLxsqu0nb%2BEwxJIIvtnjIt%2FvpUVRHmxFrmlwa67eLa9kvpwLshtWDHuCF9EKRRpXdDSHzG7aUwKe0jBSIBtuDye2ZXmXVIbP8uluJWbSosMeGg77mHfPUrOTmjW52r4ewgHJu4130PbrHq6TbvtgpdWnZPy0ZB%2B4Oy0yEBGZE5VHVeX0sP0cLrgNDs7nj6PBTDgyejMBjqxASsGKVx6mmM9cr6FHSwDOsVk90bpW0cOmI2IJ8%2BRpH9CWgbvuoO%2FXyL9h11Q9b4PxT5sE5k%2BnXD7Q6mU2R9BkJZEpxdoaulGlpYhkat4rS3GJtOEzMnyQqJ%2BiefBFnXNmKmU6Kv5mLbAH5yTVy%2F%2FdHx%2FTLAI0NYYRxW7%2BByMbrqagnHOOt9eZN%2BrObzO2XIxpvCjuBK6pI%2FmqJImpoBamqPjNzAKe1VSpyo35YEWxLAFIQ%3D%3D&X-Amz-Signature=f94293932a118a47fd8ab0265737dcb6163c667ef89b8a156ba80b2aff598b11&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=ASIA6AP2G7AKLJOKGJCJ%2F20260222%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260222T020921Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEO7%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDGV1LWNlbnRyYWwtMSJHMEUCICeI9JC4gcnZ6iWz3tH8A%2ByAKQ7BTabzCljAMZIGEIDIAiEAtFLKKVUUcUxMP%2BFqWRbl2185zjgLz%2FKFKXLmsgJ7DTIqxgUIt%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARACGgw5NjMxMzQyODk5NDAiDOvYeHKDCezhLliHjiqaBdWMP2nNbH5xtHXojzyPX7113hXw2CypHDASe6S3TgxSjArGZF1VEigzF4bkWzkvjC6eRXxGoP1xdtv2j32pQgpPPr03Er7Hlt4N%2BBGuLAa9ZyqN3msuvLeRx%2BIaw%2BkE8r9205Hw2ghrCoWASdruNdT%2BFVwEg185W6WWsOAfiF19VR2BNRfmKlpds0oRVN5A%2BlPFj%2FcQQCrLBJjF4pUcYtRMMfP5DWOSbzrnREfUVW2TnuJkMmMJ0kFFQBQiHKWaNvaOyWoyt3e73bD%2FgEPPSGlrnThNiP1%2B7uWnhYGfiuQcj0oYFuBPUVgriT0OyO8g7gMngQJK0Th3kuK4Mdhm%2FvMelxTVPQMzO6ShyClHX0vSuLpkQnblRkVPszcOPHfA59XvZWI6T%2BRZfjBEfPKu7X0cHLcbHGcjxtlCu3y1VY3mzP9zTyjOHbvfVC9SyCwZqbK%2Fc6td%2FM6pXULBYfappqq694HULwxsfDqpNj2ldC4IzLLYx0AdNad2AHRnSEtOaUW%2BFslpR0oXGfLUlFYSJ3xUbUdD%2Bv2I%2FW9YByDbxdzot0rf2YOZPQ7nJsW5AUoRT6ORFdfkoYlUB720hpsIdcri5kxfEU7yjpFWZ7W3QAkf6EYQbWPb%2BPqMkejh44z7E%2Fxzeg%2F5wr1UyJ5PqfuIxZXku%2FODpGbpqfy5EAGLj2zbUBjJvw%2BBHDAj1kLxsqu0nb%2BEwxJIIvtnjIt%2FvpUVRHmxFrmlwa67eLa9kvpwLshtWDHuCF9EKRRpXdDSHzG7aUwKe0jBSIBtuDye2ZXmXVIbP8uluJWbSosMeGg77mHfPUrOTmjW52r4ewgHJu4130PbrHq6TbvtgpdWnZPy0ZB%2B4Oy0yEBGZE5VHVeX0sP0cLrgNDs7nj6PBTDgyejMBjqxASsGKVx6mmM9cr6FHSwDOsVk90bpW0cOmI2IJ8%2BRpH9CWgbvuoO%2FXyL9h11Q9b4PxT5sE5k%2BnXD7Q6mU2R9BkJZEpxdoaulGlpYhkat4rS3GJtOEzMnyQqJ%2BiefBFnXNmKmU6Kv5mLbAH5yTVy%2F%2FdHx%2FTLAI0NYYRxW7%2BByMbrqagnHOOt9eZN%2BrObzO2XIxpvCjuBK6pI%2FmqJImpoBamqPjNzAKe1VSpyo35YEWxLAFIQ%3D%3D&X-Amz-Signature=b70925d2bf70b7fe64227c9e58a3b3196687831251f9a7ac47dc197428e71864&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=ASIA6AP2G7AKLJOKGJCJ%2F20260222%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260222T020921Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEO7%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDGV1LWNlbnRyYWwtMSJHMEUCICeI9JC4gcnZ6iWz3tH8A%2ByAKQ7BTabzCljAMZIGEIDIAiEAtFLKKVUUcUxMP%2BFqWRbl2185zjgLz%2FKFKXLmsgJ7DTIqxgUIt%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARACGgw5NjMxMzQyODk5NDAiDOvYeHKDCezhLliHjiqaBdWMP2nNbH5xtHXojzyPX7113hXw2CypHDASe6S3TgxSjArGZF1VEigzF4bkWzkvjC6eRXxGoP1xdtv2j32pQgpPPr03Er7Hlt4N%2BBGuLAa9ZyqN3msuvLeRx%2BIaw%2BkE8r9205Hw2ghrCoWASdruNdT%2BFVwEg185W6WWsOAfiF19VR2BNRfmKlpds0oRVN5A%2BlPFj%2FcQQCrLBJjF4pUcYtRMMfP5DWOSbzrnREfUVW2TnuJkMmMJ0kFFQBQiHKWaNvaOyWoyt3e73bD%2FgEPPSGlrnThNiP1%2B7uWnhYGfiuQcj0oYFuBPUVgriT0OyO8g7gMngQJK0Th3kuK4Mdhm%2FvMelxTVPQMzO6ShyClHX0vSuLpkQnblRkVPszcOPHfA59XvZWI6T%2BRZfjBEfPKu7X0cHLcbHGcjxtlCu3y1VY3mzP9zTyjOHbvfVC9SyCwZqbK%2Fc6td%2FM6pXULBYfappqq694HULwxsfDqpNj2ldC4IzLLYx0AdNad2AHRnSEtOaUW%2BFslpR0oXGfLUlFYSJ3xUbUdD%2Bv2I%2FW9YByDbxdzot0rf2YOZPQ7nJsW5AUoRT6ORFdfkoYlUB720hpsIdcri5kxfEU7yjpFWZ7W3QAkf6EYQbWPb%2BPqMkejh44z7E%2Fxzeg%2F5wr1UyJ5PqfuIxZXku%2FODpGbpqfy5EAGLj2zbUBjJvw%2BBHDAj1kLxsqu0nb%2BEwxJIIvtnjIt%2FvpUVRHmxFrmlwa67eLa9kvpwLshtWDHuCF9EKRRpXdDSHzG7aUwKe0jBSIBtuDye2ZXmXVIbP8uluJWbSosMeGg77mHfPUrOTmjW52r4ewgHJu4130PbrHq6TbvtgpdWnZPy0ZB%2B4Oy0yEBGZE5VHVeX0sP0cLrgNDs7nj6PBTDgyejMBjqxASsGKVx6mmM9cr6FHSwDOsVk90bpW0cOmI2IJ8%2BRpH9CWgbvuoO%2FXyL9h11Q9b4PxT5sE5k%2BnXD7Q6mU2R9BkJZEpxdoaulGlpYhkat4rS3GJtOEzMnyQqJ%2BiefBFnXNmKmU6Kv5mLbAH5yTVy%2F%2FdHx%2FTLAI0NYYRxW7%2BByMbrqagnHOOt9eZN%2BrObzO2XIxpvCjuBK6pI%2FmqJImpoBamqPjNzAKe1VSpyo35YEWxLAFIQ%3D%3D&X-Amz-Signature=cb6ddddce36c271cef3d45612179a38caec6c028169d2e42ab713db54b3b981e&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

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 |