Basic Soil Mechanics
What is Soil.
Soil is made up of mineral particles, water, and air. The mineral par-
ticles do not fit together perfectly, and the voids between them are
filled with water or air. The water or air in the voids is called
pore-water or pore-air.
A soil whose pores are filled entirely with water is called a
saturated soil. Most soils below the water table are saturated.
A soil whose pores are filled with both water and air is called an
unsaturated soil. The compacted fill material in embankments is an
unsaturated soil.
Pressure in the Soil
Soil is always under pressure. The combined pressure of the weight
of a soil and any applied load is called total stress. The pressure car-
ried by the soil particles in contact with each other is called
effective stress. The pressure of the water in the voids is called
pore-water pressure.
When pore-water pressure increases, effective stress is reduced.
When pore-water pressure decreases, effective stress is increased.
This principle can be expressed as:
Effective Stress = Total Stress – Pore-Water Pressure
or, in symbolic form,
ss
'=
– u
where:
s'
is effective stress,
s
is total stress, and
u is pore-water pressure.
Note The terms “stress” and “pressure” refer to force per unit area and
can generally be used interchangeably. Thus, “total stress” is the
same as “total pressure” and “effective stress” is the same as
“effective pressure.”
Rembco Geotechnical Contractors specializes in
slope stabilization,
soil nail wall,
foundation repair
and support,
grouting,
shoring,
micropile
construction,
rock drilling, and we remediate
sinkholes. We use a
problem-solving approach in the geotechnical portions of buildings, bridges, water plants, sewage plants, tunnels,
installing caisson bottom, and roads. We are experienced in these applications:
micro piles,
sinkhole repair,
permeation and
pressure
grouting,
soil nails,
cement grouting,
chemical grouting,
micropiles,
compaction grouting, and
rock anchors.
Rembco techniques apply when adding new structures: especially
rock anchor,
microfine cement,
soil nailing, and
micropile
installations for foundation support. Our specialties are
soil nails,
rock anchor,
chemical and
compaction grouting,
mini piles,
sinkhole repair,
micropiles, and
soil nailing.
