Geosynthetics August/September 2021 - 28

Construction of roads in underground mines with 3D geocells
structure due to mechanical loads from
heavy equipment.
The basic principle of operation of
FIGURE 2 Initial condition of the road: Rocky
base with irregularities and high water inflow
The patented production
technology includes
the use of ultra-strong
reinforcing threads
in the polyethylene
tape, which prevents
plastic deformation of
the cells. Thanks to the
reinforcement of the
tape, these geocells
are stronger and more
reliable than standard
3D geocells.
geonets (Renken et al. 2005). In 2011,
3D polymer geocells were used to construct
roads in underground mines for
the first time in Russia. At the same
time, the disadvantages of traditional 3D
polymer geocells became clear: the high
elasticity of polyethylene under load
caused deformations in the road structure
due to cyclic loads and, in turn, led
to forced repairs.
The specialists of Russia-based geosynthetics
manufacturer PRESTORUS
LLC found a solution to this problem
and developed a new generation of 3D
geocells, GEOCORD (Figure 1 on pages
26-27). The patented production technology
includes the use of ultra-strong
reinforcing threads in the polyethylene
tape, which prevents plastic deformation
of the cells. Thanks to the reinforcement
of the tape, these geocells are stronger
and more reliable than standard 3D geocells
and have an extended service life
of up to 100 years. Thus, the reinforced
geocell does not stretch under constant
loads and elevated temperatures,
and it maintains its geometric dimensions
and shape-particularly useful in
underground mining roads, which are
often subject to rapid destruction of the
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Geosynthetics | August September 2021
the reinforced geocell in the construction
of pavement is to redistribute the
vertical load onto adjacent cells, which
can significantly reduce the load on the
underlying foundation. To put it simply,
reinforced geocells do not allow the
crushed stone to creep, since the filling
material is placed in separate cells, and
each cell individually takes on the load.
As a result, the roadbed does not deform
and does not loosen up, and its strength
and evenness increase. Structures with
the reinforced 3D geocell can maintain
a given bearing capacity for many years,
increasing the service life of the underground
mining road.
The reinforced geocell was first
applied to construct roads in underground
mines in 2018 at two pilot sites
in the northwestern Murmansk Area
of Russia near the Finnish border. The
two sites, the Rasvumchorr and Kirov
mines, are owned by the Kirov branch of
Apatit JSC. For these tests, the geosynthetics
manufacturer designed a road that
included the reinforced geocell.
The purpose of the tests was to determine
the operability and efficiency of
geocells in the conditions of underground
mines.
For testing, a 246-foot (75-m) road
section was selected with an inclination
angle of about 8°-9° and two turns.
Before the tests, there was no road surface
as such (Figure 2); the base was rocky
with irregularities of up to 4-inches (10cm)
deep and the water flow was randomly
distributed over the entire surface
of the site (its intensity was medium to
high). Traffic intensity on the section was
high; at the time of testing, two to four
dump trucks loaded with rock mass (total
weight of about 50 tons) per hour were
moving in the " up " direction (the same
number of empty dump trucks in the
Geosynthetics August/September 2021

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