Question: Depth of Freezing and geotechnical investigation 1

[GeoGrouting]

I am designing the founadation for a monument.

1. What is the depth of freezing for foundation design in Hope, BC.

2. The soil is expected to be silt and fine sand. I know my foundation width is 1.4 m. Does it meen that I should study the ground 2.8 m below the foundation bottom line or investigation (by test pit) 1.2 m below the foundation would suffice.

3. For dead-man anchor, what is the suggested depth of geotechnical study in the above soil?

Thank you

 

[PEinc]

From your three questions, it sounds to me like you need more help than this forum can or should provide. Sounds like you need an experienced engineer.

1. The frost depth requirement should be in the local building code.
2. How can we tell you how deep to investigate if we don't know your loads, the ground conditions, or what type of foundation you think is needed?
3. What is the deadman anchor for?

http://www.PeirceEngineering.com

 

[GabionGuy]

If you are working in Canada, i suugest you review the Canadian Foundation Engineering Manual. This should answer most of you questions.

 

[16adams]

I typically calculate settlement from the soils information gained to a depth of at least 2 times the width of the proposed footing. I typically have a boring that is several meters deeper than this to ensure that there isn't something terrible below. The frost depth is independent of this. The codes and local experience will come in to play for this answer. In Illinois, the frost depth is between 0.6 meters to 1.2 meters. I am afraid I have no idea as to the depth of frost in Hope, B.C.

Hope this helps

 

[VAD]

Be careful of silt and fine sand and a high water table that may be within the depth of 1.4 m below the foundation level. Frost heaving forces in these soils can be large. The weight of your monument may not be sufficient to counteract heave force hence the reason perhaps for your deadman anchors. Helical piles may be your answer below the base of the monument. You should go 5 to 6 m with your investigation. I realize that you do not want to spend money drilling any holes. Testpit may be an alternative but is destructive and not good at location of installation of monument and is not recommended. Drill hole is better in this instance. Testpit okay if you place outside of the location of the monument.

Some insulation below monument can assist in resolving frost heave issues if you are worried about this aspect.

Remember whether the structure is large or small the ground conditions and applied loads along with environmental load factors generally dictate the solution.