1525
Technical Committee 203 /
Comité technique 203
anchors on increases stability of a slope many. Sensors of
movements received values of horizontal and vertical
deformations of a board of a ditch. Soil movements in natural
state was much more movements of the slope fixed by soil
anchors.
1- Scale of compression of a spring; 2 - Basic castors; 3
Spring; 4-Temporary partition in the middle of the stand; 5 -
Transparent plexiglas; 6 - Directing rails.
Figure 2. The general view of an experimental tray.
4. APPLICATION OF THE RECEIVED RESULTS IN
PRACTICE
At construction of underground by an open way by primary
goal is to provide stability of walls of foundation ditches.
Constraint of conditions of a platform does not allow to provide
a corner of a natural slope for slopes of a foundation ditch.
Development of foundation ditches should be carried out under
condition of fastening walls from destruction. Supporting
design should provide reliable work of all adjoining buildings
and constructions.
Analyzing geological conditions to become obvious, that
the basic thickness of a fixed file is generated GL-4 and GL-5,
that is gravel of a ground. Results of researches show that the
parameters of durability determined by researches by a standard
technique do not reflect to the full a nature of resistibility gravel
of a ground. For GL-4 it is possible to recommend a corner of
friction of 48 degrees, for GL-5 up to 50 degrees.
By results of calculations with use of experimentally
established mechanical properties of soils and programs Lira 9.6
and PLAXIS the optimal variant of fastening of walls of a
foundation ditch (Figure 3) is chosen. The used settlement
programs are based on application of a method of final elements
for modeling earth geological conditions and the accepted
constructive decisions of fastening of boards of foundation
ditches. Settlement seismicity of a site made 9 points on scale
MSK-1964. Seismic loading is enclosed in calculations
kvazistatical by away. The three-storied circuit is accepted.
Height of circles are accordingly 9m, 9m and 6m. The basic
bearing elements of a protection are vertical racks as piles.
Diameter of piles is accepted 168 mm. The pile inside is
completely filled by concrete. Stability of racks is provided with
inclined earth anchors such as "Titan". For each circle the step
of arrangement of vertical racks both required quantity and
length of anchors are picked up, (M.I.Gorbunov-Posadov 1985,
L.N Ginzburg. 1979).
On the circuit (Figure 3), it is visible that for fastening the
top circle is required two lines of anchors, length of 12 and 10
meters. Section of anchors was as a pipe with external and
internal diameter 30 mm and 11mm accordingly. For fastening
the second circle it is required already three lines of such
anchors. Steady position of the third circle is provided only five
lines of anchors. The required section of anchors was increased
up to 40mmexternal and 20mminternal diameter.
Control check is executed with use of program PLAXIS
Figure 3. The Deformed circuit of the fixed slope in program PLAXIS
5. СONCLUSIONS
1 At excavation of deep ditches of the most optimum the
scheme of excavation and soil fixing by circles is. With a
height of circle more than 6 meters fixing of soil is an
indispensable condition, irrespective of a type of soil in which
they are constructed. Fixing in difficult geological conditions
and in seismically active areas is especially important.
2 Laboratory researches in a tray showed efficiency of
application of soil anchors for ensuring stability of a slope of a
ditch. Tests are carried out on a mix modeling properties of clay
soil in a natural not water-saturated state.
3 If ditches it is dug out in pebble soil, for fixing of boards of
ditches up to 9 meters high it is possible to use tube concrete or
ferroconcrete piles with a diameter from 150 mm. It is
expedient to pile to arrange in two ranks, having connected
them on top a ferroconcrete plate. Stability of vertical racks is
provided with soil anchors. Anchor length, and also length and
diameter of an anchor it is necessary to select only for
calculation.
4 In a case when ditches are arranged in weak clay or water-
saturated soil use for fastening of walls of a ditch of only soil
anchors insufficiently. From experience it is visible that reliable
work of fastening of a ditch requires application of struts and
other horizontal communications.
REFERENCES
SNIP RK 2.03-30-2006.
Construction in seismic areas
. - Astana.
L.A.Avakjan.
Questions of a technique of researches of
physicomechanical properties gravel soils on the basis of
experience
. Moscow, 1981, 28-33
V.I.Feodorov, V.V.Sergevnina.
Influence of a clay filler on durability
gravel - clay soils
. Magazine «Bases and foundation, the mechanics
soils №6». Moscow, 1973. pages 13-15
