1 scope
This technology is applicable to industrial
and civil buildings and structures of large Foundation pit (Groove), trench and
large area flat ground mechanical excavation.
2 construction preparation
2.1 the main tools:
2.1.1 excavation machinery: excavators,
bulldozers, scrapers, dump truck, etc.
2.1.2 General tools: shovel (pointed, flat
two), trolleys, small white lines or 20th, wire and steel tape and adjustable
triangle, and so on.
2.2 operating conditions:
2.2.1 prior to excavation, construction
should be based on programme requirements, underground, above ground
obstructions within the construction area cleared and closed.
2.2.2 location of the building or structure
or ground positioning control lines (piles), standard level, and gray line of
the slot size, must be inspected and through pre-screening procedures.
2.2.3 night-time construction, there should
be adequate lighting; in dangerous places should be set clearly marked,
excavation sequence and reasonable arrangements to prevent wrong to dig or
over.
2.2.4 when the excavation of Foundation pit
water level tank, trench, according to the local geological information, take
measures to reduce the water table. Generally fell to face following 0.5M
before the excavation.
2.2.5 construction machinery access to the
site through the roads, bridges and unloading facilities and so on, should be
checked in advance and, if necessary, to reinforce or expand and other
preparatory work.
2.2.6 selected for earth-moving machinery,
construction should be based on the topography of the area and operating
conditions, soil type and thickness, total quantity and duration into account,
to the level of play of construction machinery efficiency to determine, prepare
construction program.
2.2.7 layout of construction area running
routes, according to an area the size of the project, mechanical properties,
transport distance and terrain conditions to be determined.
2.2.8 in mechanical construction could not
work parts, cleaning and repair of slopes slope bottom, shall be equipped with
manually.
2.2.9 familiar with the drawings, technical
clarification.
3 operational processes
3.1 process:
Determine the order of excavation and slope
end of segment dug under the tiered average → → Bian Heqing
3.2 determination of slope:
3.2.1 in the natural humidity of the soil,
excavation of Foundation pit (slot), when the trench while digging depth does
not exceed the provisions of the following, do not slope without support.
3.2.1.1 dense, medium dense sand and gravel
soil (filled with sand) 1.0RN.
3.2.1.2 hard plastic, plastic, clayey silt
and silty clay 1.25m.
3.2.1.3 hard plastic, plastic clay and soil
detritus (filled with clay) -1.5M.
3.2.1.4 of hard clay in a 2.0M.
3.2.2 above provides depth in 5M when soil
with natural humidity, uniform structure, hydrological conditions, without
water, without support of Foundation pit (Groove) and pipe must slope. Steepest
gradient of the slope should comply with the provisions of l-3.
Table 1-3 of various types of soil slope
Slope (height: width)
Top top no load dead load top load
1 medium dense sands 1:1 1:1.5
2 medium dense soil detritus (filled with
sand) 1:0.75 1:1 1:1.25
3 hard plastic light loam 1:0.67 1:1
4 medium dense soil detritus (filled with
clay) 1:0.50 1:0.67 1:0.75
5 hard plastic clay, clay 1:0.33 1:0.67
6 old loess 1:0.10 1:0.33
7 soft (after it has been well-point
dewatering) 1:1.00--
Note: when there is a mature experience,
are not subject to the table limit.
3.2.3 use longer temporary slope gradient
should be based on engineering geology and slope height, combined with similar
stability of soil slope value. Such as geological conditions, soil (or rock)
more uniform quality, height in the 10m temporary slope gradient should be
determined according to table 1-4:
Table 1-4 of the various types of soil cut
slope
Categories of soil slope (height: width)
1 sand (not including sand and silty sand)
1:1.25~1:1.15
Hard 1:0.75~1:1.00
Hard plastic 1:1.0~1:1.25
Filling hard, hard plastic clay
1:0.5~1:1.00
Filling sand 1:1.00~1:1.50
Note: when there is a mature experience,
are not subject to the table limit.
3.2.4 cutting through different types of
soil (or rock) or depth of more than 10m, its slope can be made into a
broken-line or steps.
3.2.5 city cut due to limitations of nearby
buildings, and when the piles are used, you can slope, but piles of
construction programs.
3.3 excavation (Groove) or when a trench
should rationally determine the depth of excavation sequence, the route and
the.
3.3.1 large Foundation pit excavated by
bulldozers (Groove), generally from both sides or top (vertical) moving,
towards the middle or top soil, temporary accumulation and horizontal soil away
from the Foundation pit (Groove) on each side.
3.3.2 excavation of large Foundation pit
using scrapers (Groove), vertical branch, stratified according to the grade
line of shovels down, but each floor centerline location should be slightly
higher than the sides to prevent accumulation.
3.3.3 used backhoe, shovel excavator
excavation (Groove) or when the channel, there are two methods of its
construction;
3.3.3.1 end dig law: excavators from the
pit (Groove) or ends to back of the trench method of excavation. Configuration
on either side of excavators dump truck shipments.
3.3.3.2 lateral excavation methods:
excavation side along the pit (Groove) or the side of the trench, dump trucks
on the other side of the ship.
3.3.4 when excavators move along the cut
edge, machinery from the upper edge of the slope shall not be less than the
width of the Foundation pit (Groove) or trench depth of 1/2. As the digging
deeper than 5M, should be determined according to professional construction
programmes.
3.4 excavation should be staged
sequentially from top to bottom. Made in a slope at any time, in order to
facilitate emptying.
3.4.l in the excavation process, should
feel free to check out the Groove wall and slope of the State. The depth is
greater than 1.5M, according to the changes in soil conditions, we should do a
pit (Groove) or trench support preparation, to prevent collapse.
3.4.2 excavation (Groove) and the trench
shall not be dug to the design height of the following, if not exactly digging
base elevation is to design, persistence of elevation above a layer of soil is
not dug, to copy after ping, dug by hand.
Persistence layer: scrapers, bulldozers
dug, 20cm; backhoe used backhoe, shovel and shovel dug, 30cm.
3.4.3 in machinery construction dig into
Earth, mining should be manual at any time, and trolleys to transport Earth machinery
to dig the place, so as to use the machinery of cherry-picking.
3.5 repair help and clear bottom. From
trough bottom design elevation 50cm help, copy line, nailed a small wooden
stick, and interned with artificial layers of cherry-picking. While both ends
of axis (centerline) Latrun line (with a small wire or wire), check from the
slot size, determine the width of Groove standard, to repair slot. Finally
clear the bottom of Earth.
3.5.1 the bottom after repair level,
quality inspection and acceptance.
3.5.2 excavation (slots) for earth moving,
in field conditions when stacked, must have sufficient backfill need good soil;
excess earth should be removed to avoid second handling.
3.6 rain, winter:
3.6.1 excavation should not be conducted
during the rainy season, or work surfaces should not be too large, should be
done piecemeal, by staging.
3.6.2 rain during construction in the
excavation (Groove) or when the trench, should pay attention to slope
stability. If necessary, appropriate slow slope, or braces. While in the pits
(Groove) outside surrounded by Earthen berms or digging ditches, prevent
surface water from entering. Always check on the slope, support, an embankment
and found the problem to deal with.
3.6.3 excavation should not be in the
winter. If it is necessary at the time of construction in winter, its method of
construction should be carried out by winter programme.
3.6.4 to prevent freezing when excavation
and earth-moving, but before the freeze, covered with insulation material or
soil tilling raking, plowing depth should be determined according to local
temperature conditions. Not less than 30cm.
3.6.5 excavation (Groove) or when a trench,
you must prevent the Foundation of Foundation soils and cold. Should set aside
an appropriate thickness of basement elevation above the loose Earth. Or cover
it with other insulation materials. If the excavation Earth causes nearby
buildings or structure of ground and Foundation exposed, antifreezing measures
should be taken to prevent freezing damage.
4 quality criteria
4.1 project:
4.1.1 column base, pit, trench, trench and
soil soil of the site must comply with the design requirements and no
disturbances.
4.2 allowable deviation, as shown in table
l-5.
Earthworks excavation and site grading
allows deviation
Serial number item tolerance (mm) test
method
2
3 surface elevation
Length, width,
Slope on the steep +0-50
-0
Does not allow for level checking
Theodolite, cable and standard inspections
Observation or using a slope-scale
inspection
Table 1-5
5 finished product protection
5.1 positioning axis standard pile, pile,
standard and standard, Dragon door, dug Earth must not hit touch, nor may you
rest on the Dragon door. And should always measure and checking its position,
level elevation and slope meets the design requirements. Positioning standard
benchmarks and standards should also be regularly repeated and check that they
are correct.
5.2 when the excavation should be the
protection of neighbouring buildings or structures, roads, pipelines, such as
subsidence and deformation will occur. And design units or units should be
consulted when necessary, protective measures, and settlement and displacement
observation during construction.
5.3 If artifacts are found in the
construction or Tomb Raider, should be protected and should be reported to the
local authorities in a timely manner, to continue construction. If there are
any permanent target for the measure or established long-term geological and
seismic observation points, and so on, should be protected. Laying in the
ground or underground pipelines, cables, lots of earth-moving construction,
prior written consent of the relevant authorities, construction should take
measures to prevent damage to the pipeline, causing a serious accident.
6 quality problems to be noticed
6.l basement overbreak: excavation (Groove)
tunnel shall not exceed the base level. If the place when over, it should be
agreed by the design unit, not allowed to deal with.
6.2 base unprotected: pit (Groove)
excavated to minimize soil disturbance. Case basis not timely construction, can
be reserved in substrate elevation above 30cm soil is not dug, dug until you
can do basic.
6.3 construction order unreasonable should
be carried out strictly according to the construction plan set and construction
order Earth excavation, care should be taken first from the lower excavation,
subparagraph layering, in turn, form a certain slope to facilitate drainage.
6.4 sinking of construction machinery:
construction must be aware of soil and groundwater. Bulldozers, scrapers, takes
in the underground water level 0.5M push above shoveled Earth; backhoe digging
in the ground-water level above 0.8M is generally required, in case of
mechanical weight sinks. Shovel Excavators digging the step height shall not
exceed the maximum cutting height of 1.2 times.
Undersize 6.5 excavation, slope too steep:
pit (Groove) width of the excavation or trench bottom and slopes, in addition
to considering the size requirements should be based on the need to increase
the Width of the construction, such as drainage, support structures, such as
the width you want.
6.6 when rainy season, trench, pit should
be set aside at the end of 30cm soil, then you hit concrete pad to the design
height.
7 quality records
This standard shall meet the following
quality records:
Engineering geology investigation report of
7.1.
Engineering location measurement records.
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