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There're site investigations for the line route, can you inform me the soil classifications / Types?

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Question added by Ahmed Farag , Transmission Engineering Specialist , Saudi Electricity Company
Date Posted: 2013/10/29
aftab aftab
by aftab aftab , Site Engineer , K.C. Power Infra Pvt. Ltd.

there are many type soil classified for line route.

1. Normal Dry type

2.Wet type

3. Partially submerged type.

4. fully submerged Type

5. wet black cotton type(WBC)

6. Submerged fissured rock type (SFR)

Karsten Clotz
by Karsten Clotz , Owner , Clotz

Hi

 

We use soil nominations as follows:-

 

 

      1. Hard Rock (bearing pressure ±2 000kPA)

        This is a category for hard, to very hard, solid or moderately fractured continuous rock. The Dynamic Cone Penetrometer (DCP) will have no penetration with a distinct sound that rock has been encountered. The sliding hammer will “bounce” on the anvil.

        An example of Hard Rock can be Granite, Yster Klip or Blue Rock.

         

      2. Soft Rock (bearing pressure ±800kPa)

        This is a category for weathered or decomposed very rock to continuous rock. The DCP will have a very low penetration rate with a DCP value of10 or more (or penetration of2 to10mm per blow). Do not penetrate for more than200mm as it may be very difficult to remove the DCP.

        An example of Soft Rock can be Ou Klip.

         

      3. Soil Type1 (bearing pressure300kPa)

        Consistency

        This is the category for competent soil with equal or better consistency (strength or toughness) than would be encountered in stiff cohesive or medium dense cohesionless soils above the water table.

         

        Firm of stiff cohesive soils:

 

  • Moulding of soil with fingers is difficult to impossible. Excavation with a spade is difficult and picking is required.

     

    Medium dense non-cohesive soils:

  • Considerable resistance to shovelling or penetration by hand bar.

     

    Texture

    Cohesive soils:

  • Very stiff clay, sandy clay, silty clay, sandy slits and silty sands.

     

    Cohesiveless soils:

  • Compact, well graded gravels, sands and gravel mixtures, permanently above all water table

     

    The DCP will have a low penetration rate with a DCP value of6 to10 (or10mm to17mm per blow)

     

 

      1. Soil Type2 (bearing pressure150kPa)

        Consistency (degree of density)

        A less competent soil than type1 with equal or better consistency than would be encountered in firm to stiff swelling cohesive soils or dry, poor graded loose to medium dense soils above the water table.

         

        Firm of stiff swelling cohesive soils:

 

  • Soil can be moulding with fingers with strong to very strong pressure. Freshly exposed surface shows faint heel marks when stood upon. Excavation with shovel is difficult.

     

    Medium dense to loose soils:

  • Having little to considerable resistance to shovelling or penetration with hand bar.

     

    Texture:

    Cohesive soils:

  • Firm to stiff clay, sandy, sandy slit and silty sands. Clayey soil will have a smooth texture and will tend to stick to the DCP rod when removed.

     

    Cohesiveless soils:

  • Poor to well graded sands, gravels and gravel-sand mix, permanently above all water tables. Dry sand will have a course texture.

     

    The DCP will have visible penetration rate a DCP value of4 to6 (or17mm to25mm per blow).

     

    The maximum bearing at foundation depth shall be150kPa

     

 

      1. Soil Type3 (bearing pressure100kPa)

        Consistency (degree of density)

        This is the category for dry loose cohesionless soil or very soft to soft cohesive soil.

         

        Soft to very soft cohesive soils:

 

  • Mouldable with ease to manageable with fingers. Forms faint to distinct heel marks on freshly exposed surface when stood upon.

     

    Very loose to loose cohesiveless soils:

  • Easily excavated with spade and penetrable with hand bar.

     

    Texture:

    Cohesive soils:

  • Soft to very soft clay, sandy clay, sandy silt and silty sands. Clay will stick to the DCP rod sand will provide a clean rod when removed after the test.

     

    Cohesiveless soils:

  • Poorly graded sands, gravels and gravel-sand mixtures, permanently above all water tables.

     

    The DCP will have visible penetration rate a DCP value of2 to4 (or25mm to50mm per blow).

     

    The maximum bearing at foundation depth shall be100kPa

     

     

 

      1. Soil Type4 (bearing pressure50kPa)

        Consistency (degree of density)

        This is the category for submerged cohesionless and cohesive soils. This includes all soil below the permanent water table, including soils below a re-occurring perched water table, or permeable soils in low-laying areas subjected to confirmed seasonal flooding.

         

        The DCP will have a very high penetration rate with a DCP value of1 to2 (or50mm to100mm per blow).

         

        The maximum bearing at foundation depth shall be50kPa

 

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