Geotech Inestigation · MCU22/0192

The samples hand collected and classified on site from BH 2 at a depth of 600 mm
and BH 4 at a depth of 600 mm below the existing surface level returned a linear
shrinkage result of 12.6%.

The expected surface movement (Ys), due to seasonal moisture changes in the soil
encountered, is as follows

 

Ys Value = 21 mm

 

 

 

 

 

 

 

 

 

 

 

 

 

Predicted Surface Movement Class
Ys= < 20mm S
Ys =>20-< 40 mm M
Ys => 40-< 60 Hl
Ys => 60 ~e 75 mm H2
Ys=>75 mm E
Problem sites P

 

Note: The proximity of trees and their effect on foundations should be considered when
determining specific engineering assessments, and for foundation/footing design.
Appendix B of AS 2870-2011 indicates that to reduce, but not eliminate, the possibility of
damage to the footings, trees should be restricted to the following distance from the
building (where rows or groups of trees are present the distance nominated below must
be increased, and similarly the Ys Value listed above may need to be increased) : 75% of
the mature tree height, for class “M” sites, 100% of the mature tree height, for class
“H 1” sites, and 150% of the mature tree height, for class “E” sites.

Note: This classification above has been derived from test work performed on the soil
profile encountered on the day of our fieldwork. Any further filling of the site or
excavation into the soil profile, may result in a different classification.

Temporary Excavations.

Where temporary excavations are performed for footing or services up to 600mm
deep, natural soils may have minor or no stability problems, however deeper
excavations have a possibility of collapse more readily and shoring of vertical
excavation may be required. Where an existing excavation has been filled with
uncontrolled fill, all locations above a line 30 degrees for sands and 45 degrees for
clays above the horizontal may be unstable and may not support any structure — see
attached critical depth line diagram.

 

Unearthed Geotechnical P/L. 4 Site Investigation Report 022-164