Civil Engineering Reference
In-Depth Information
Cut and fill is ideal if the fill is used to provide a flat area for a garden, as is the case
with our home in central Victoria. Many an engineer would disagree, but I would prefer
to risk developing my vegetable garden on the fill rather than my house. The veggie
garden will benefit from the looser soil and it will be easier to dig. I strongly suggest you
keep the fill area for the garden.
Retaining the soil at the face of a cutting
Having established the total area that needs to be flat, including the required solid area as
opposed to fill, you will need to decide on your method of retaining soil at the face of the
cutting. The method of retaining this soil will have a bearing on the area to be marked
out on the surface of the site to produce the appropriate flat area. If you are planning on
building a retaining wall to stabilise the cutting, the surface markings will need to be
increased to accommodate the installation of this wall plus the drainage and aggregate to
be used behind the wall. If the retaining wall is greater than 900 mm high you will need
to have an engineer design the retaining wall. This design forms part of you application
for a building permit. The other method of dealing with the face of the cutting is to do
what is known as 'batter back'. This method simply modifies the face of the cutting from
a vertical face to a 45-degree angle. With this method it will be necessary to increase the
dimensions of the surface marking by one metre back into the cutting, for every metre in
depth. This method is extremely popular in a rural setting where there are fewer
limitations on space. In a city environment it is often difficult to accommodate this
method, as the total land area available is much more restricted.
Disposal of the soil removed
It is important when deciding on the total area of the fill and excavation, to take into
consideration where the excavated soil is going to be put. If the excavated soil is to be
removed from the property it will not affect the job. However if the soil has to be
accommodated on the building site this needs to be kept in mind when designing the
cutting.
When soil is excavated it will double in volume, so allow for this in your calculation
for the disposal and/or relocation of this soil. If you are planning to remove the soil from
your land, it will save you a considerable amount of time and money if you can locate a
site as close as possible to your property to dump the soil. You might consider advertising
in the local paper for anyone that requires free clean fill.
The excavator may give you a quote for the work including disposal of excess soil but
it is more likely they will charge by the hour. To have a place to dump the soil in close
proximity to your property will affect any quote you are given. When it comes to
excavations time really is money. If you are unable to dispose of the soil free of charge
there will be additional cost for dumping the soil in land fill. This is a lesser issue in
smaller towns where you can sometimes negotiate a special rate for disposal of clean fill,
but the cost can get away from you in a city setting so don't make the assumption it will
take care of itself.
