The type of soil determines the strength and stability of trench walls. In most Canadian Provinces, soil types fall into four categories.
Canadian Soil Classifications |
|
| Type | Description |
| Type 1 | This type of soil is so hard that it is close to rock. |
| Type 2 | Easily excavated with backhoe, remains intact for short time only – i.e. silty clay |
| Type 3 | Previously excavated, flows through fingers – i.e. sand |
| Type 4 | High moisture content, sensitive to vibration – i.e. quicksand, clay |
In the U.S. there are also four types of soil, but the naming convention is different.
U.S. Soil Classifications |
|
| Type | Description |
| Stable Rock | Natural solid mineral matter that can be excavated with vertical sides and remain intact while exposed. |
| Type A | Cohesive soils. i.e. clay, silty clay, sandy clay, clay loam |
| Type B | Cohesive soils but less than Type A – i.e. angular gravel; silt/silt loam; previously excavated |
| Type C | Cohesive soils but less than Type A/B – i.e. gravel, sand and loamy sand, submerged soil, soil w/ freely seeping water, unstable submerged rock |
Soil.Types.Canada Soil Types United States
