Trenching
by a Hydraulic Piston Splitter
A piston splitter can clear
hard rocks in trench lines efficiently
Trenching in rock site takes lots of time and manpower. With a rock drill and a hydraulic rock splitter and an excavator with shovels can clear 60 cube meter rocks per day.
Drill pattern:
A drill
pattern( plan ) is based on many factors such as kind of rock, tunnel size, work duration, the
place ( free surface or normal body rock)and the type of equipment you use.
. In case we make a trench as below photo 1 ( 2m W x 3meter
L ) in medium hard rock, the basic
spacing is 500mm distance. When the rock
is harder than this, you need to keep the space closer ( 500 à 450mm ), When the rock is softer, you can increase the spacing wider.
Photo 2 shows drill plans for 2
meter wide trench excavation. If the
trench starts from top to down ,the first line has 5 holes with the spacing S3,
S4,S5 side by side . It is roughly 50cm wide. The second line has 6 holes.
Boundary lines on the left and right side have spacing of close distance,i.e
25cm between top to down.
Photo 2 ---- Keep clearing for free face after splitting.
( Plan view of drill pattern- top) and (sectional view-bottom )
” Drilling
Angle for keeping “free face
1.
Boundary Line bores: Drill straight closely along the side lines.
2.
Intermediate bores: Drill slanted so that “free face is kept
continuously.
Photo 2 ---- Keep clearing for free face after splitting.
( Plan view of drill pattern- top) and (sectional view-bottom )
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( Diagram 3 ) Intermediate bores need slanted drilling to
keep free face
The free surface line of top round
boundary need be drilled closely with only 20~25㎝ space ( add one in the between normal holes). The free face along
the top border line is used for easy breaking of rocks during splitting..
Making free face in the center is
another important to keep for continuous splitting . In this case splitting is
done from the left to right .
Manual splitter size of 95㎜ diameter cylinders are recommended.
The number of pistons are between 7~9.
Shorter cylinder with 7 pistons are light and efficient. Longer cylinder with 9 pistons are rather
heavy for a manual worker. To assist the lifting splitter , lift is used .
Multi number of splitters are powered
by one power pack. Either 4 or 6 splitters are used as a set of machine. When the width is 2 meter wide, 6 splitters
are used in line.
Tips for
drilling.
An
important tip for drilling of trench is to drill to the targeted depth. In this
example, the depth is 3 meter deep.
Rock Splitter recommended,
A manual rock splitter of 95mm diameter ( HRD 9507, HRD9509 ) is recommended for trenching work. The number of splitters is considered in terms of width of the trench.
As explained before, splitting in a line covering the whole width saves lots of time.
When the spacing is made with 50cm distance, 2 meter width wll require at least 5 splitters.
Rock Splitter recommended,
A manual rock splitter of 95mm diameter ( HRD 9507, HRD9509 ) is recommended for trenching work. The number of splitters is considered in terms of width of the trench.
As explained before, splitting in a line covering the whole width saves lots of time.
When the spacing is made with 50cm distance, 2 meter width wll require at least 5 splitters.
As the
splitter length is either 590mm ( SR 9507) or 730mm ( SR9509), each splitter is
inserted 4~5 times for splitting. It is usual to see drilling time take more
than splitting. So it is recommended to use more powerful splitters than weak
ones.
Key Point in
Excavation
In
trenching work, a key point in excavation is to
(1) drill the whole depth (2) split the drilled line in one shot. If the ditch depth is 3 meter deep, you need
to drill 3 meter deep at a time. Then
splitting is done from the near line to
free face.
If the splitter length is short of the whole depth, you need to insert the cylinder twice or three times. After the splitting is done ,next line of splitting is tried.
If the splitter length is short of the whole depth, you need to insert the cylinder twice or three times. After the splitting is done ,next line of splitting is tried.
As
seen on above photos, mucking is done just after splitting . This serial work
should be arranged considering the each process time. In any case, drilling
takes the most of time, splitting time is less than drilling time. Mucking
takes the least time.
Performance of
hydraulic trenching
Spacing
of 50cm between holes. Drilling time for
3 meter deep hole: 3 minutes.
Based on above basic assumption, drilling time
for 20 holes takes one hour. Splitting
time for 20holes with 95mm splitters of
6 cylinders 600mm long takes 50 minutes.
So in one hour, 10 cube meter rocks can be drilled and
split. Assuming 20~25% waste time, 60
cube meter of rocks can be cleared in a day time of 8 hours by hydraulic rock splitting system.
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