Slope Stability AG-220616-RPT-G-01_[Rev A]

 

 

‘Tree root

‘Trees and thar are allowed to grow in the vicinity of footings

can cause foundation soil movement in two ways:

© Roos that grow under footings may increase in cross-sectional
size, exerting upward pressure on footings.

* Roots in the vicinity of foocings will absorb much of the moisture
in the foundation soil, causing shrinkage or subsidence.

|Unevenness of Movement
‘The types of ground movement described above usually occur
unevenly theoughout the building's foundation soil, Settlement due

to construction tends to be unevei because of;

© Differing compaction of foundation soil price tn construction,

* Diffcring moisture consent of foundation soil prior to construction,
Movement duc to non-constraction causes is usually more uneven
still. Erosion can undermine a footing that traverses the flow or can
create the conditions for shear failure by eroding soil adjacent to a
footing that runs in the same digectian as the flow.

Saturation of day foundation soil may occar where subfloor walls
create a dam that makes water pond. It can aleo occur wherever there
isa source of water near footings in clay soil. This leads to a severe
reduction in che strength of the soil which may create local shear

Seasonal swelling and shri of clay soll affects the perimerer of
the first, then spreads to the interior, The swelling
process Da pee pda i oron

the weather ude where the land is flat, Swelling gradually reaches the

i from unde footings sending to create
subsidence of the part of the structure under which it occurs,
Brickwork walls wall resist the stress created by this removal of
poppet by Setting Dee So s until the bricks or the
mortar bedding fail masonry has tesistance. Evidence of
failure varies according to circumstances and sympeoms may include:
* Seep cracking in the mortar beds in the body of the wall or
sbore/below openings such as doors ot windows.

* Vertical ing, in the bricks (usually but nor necessarily in line
with the vertical beds or perpends).

po pany Loy hata a ea pr rnponcps "sae
sometimes rattling ornamenss etc.

Seasonal
foundation soll due w rainy periods first lifts the mest
extremities of system, then the remainder of the
seers 3 seer Siicrunkovest
to lift internal swelling firs sends to create a
dish effect, because the foonings are pushed higher than the
internal ones

the floor car be there visible:
Seago he por age tea es
As the moisnure completes its journey vo the
innermost areas of the the internal footings will rise. If the
spread of meisture is roughly even, it may be thar the will
spontly teappees, ber ic a mare eter don be
uneven. a difference rather in

In with timber by bearers

 

Doming and dishing are also affected by weather in ocher ways, In

Movement caused by tree

fn rooes will exert an preeure on footings,

whereas iat ts detiag Nocmees twee of shrub roots will vend

to remove support from footings by inducing shrinkage.
caused by the structure itself

ing where it can. It will attempt to
ded foundat pet

Jn the event of construction settlement, cracking will usually remain
unchanged after the process of settlement has ceased.

cracking will usually continue to develop
wewil the origi cuts bas buen wovetied, or ell dhe ssbeidonce

neutralised the affected portion of | and the

structure has stabilised on other footings thar remain

In the case of coer ee cee dani
return to its original position: i a however it
is more likely that the rotational effect will mot be exactly reversed,
and it is also uswal that brickwork will sectle im its y

r

the problem. This means always the case,

ree ofcneke hockeeed teen aaa eager oe
seriously.

Upheaval caused by