Theoretical basis
Cone Penetration Test (CPT) or more
commonly referred sondir is one field surveys are useful for estimating the
location of the bedrock. This test is done on a layer of clay. From this test
cone penetration resistance values obtained. The cone penetration resistance
is the resistance of land against the conical tip that is expressed in force
per unit area. While the barrier is attached to the casing shear resistance
bikonus in force per unit length. Value cone penetration resistance and
adhesion barriers can be known from the readings on the manometer
Deifinisi sondir
Sondir
is a testing ground to determine the characteristics of the soil is done in the
field or at a location that will do the construction. Sondir there are two
kinds, the first is a mild sondir with a capacity of 0-250 kg / cm² and the
second is heavy with a capacity of 0-600 sondir
kg / cm². Disondir suitable soil types
with this tool is the land that does not contain a lot of stones.
The main components sondir
The main component is a conical sondir
inserted into the soil in a way suppressed. Pressure on the tip cone when the
cone moves downward due to pressure, read on manometer every depth of 20 cm.
Pressure from the top of the cone is channeled through a steel rod that is inside
the pipe sondir (which can move freely, not stuck pipe sondir). Similarly,
sustained pressure cone when pressed into the ground, passed through a steel
rod in the sondir pipe upwards, to a manometer.
Results of tests sondir is used for:
Determine what type or types of
foundation that will be used
Calculate the carrying capacity of the
native land
Determines how the foundation should be
laid later
Experiment destination
1.Mengetahui
cone penetration resistance.
2. Knowing
the barriers attached to the ground.
Advantages and Disadvantages Sondir
Tools
Advantage:
Quite economical.
If the boring soil samples can not be
taken (soft soil / sand).
Manentukan can be used with good soil
bearing capacity.
More reliable empirical correlation.
Can help determine the position or the
depth of the drilling.
In practice test is highly recommended
sondir accompanied by other test both field tests and laboratory tests, so that
sondir test results can be verified or compared with other tests.
Can quickly determine the adhesive layer
of hard soil.
Can be estimated difference layer
Can be used in layers of fine-grained
Both are used to determine the location
of the ground water level.
Losses:
If there are loose rocks used to give an
indication of the hard coating is wrong.
If the appliance is not straight and not
working properly then the results obtained
obtained could be detrimental.
Land can not be known directly
Tools and materials
Tools:
Machine sondir
A set complete with handlebar stem sondir
in length 1 meter
Manometer 2 pieces
- Capacity 0-50 kg / cm²
- Capacity 0-250 kg / cm²
One fruit and one patent Bikonus cone.
Square plates 2 sticks
One set (2) pieces of armature
Material :
Oil Hidrlolik
Ground
Pictures tool sondir
WORK STEPS
Determine the location of the flat
surface
Installing four anchor into the ground
by rotating armature player using the key (key T). then install the two square
plates in SAMING yng elongated armature. The distance between the armature and
the distance between the two plates adapted to the size sondir machine.
Sondir engine installed perpendicular
and equipment at the test site, which is reinforced with a short iron plate to
clamp the machine and reinforced with mor locking armature mounted into the
ground.
Installing Traker, press the handlebar.
At first the emphasis conical tip will move to the bottom depth of 4 cm, then
manometer reads stating resistance ends. In the subsequent suppression cone and
mantle moves
4cm. Value on manometer is read is the
value of pressure and resistance sticky end.
Pressing the outside to the depth of the
new handlebar, handlebar emphasis performed until any additional depth of 20
cm.
Doing the same with working steps above
until the manometer readings three times in a row shows the value ≥150 kg / cm2
and when the pressure has reached its maximum sondir machine or felt to have
reached a hard soil, then this test can be stopped.
Flowchart experimental procedure sondir
CALCULATION barriers attached
- Barriers Gluey (HL)
HL = (JP-PK) x A / B
Where :
JP = Total Resistance and Barriers Konus
Gluey (px2)
Penetration Resistance PK = Konus (PX1)
A reading of 20 cm = Interval
B = Factor Tool Konus = L / L piston =
10 cm
- Total Barriers Sticking
JHLi = Z HL
Where :
i = Depth Layers The Evaluated
Z = Zigma
Observations and Data Processing
At this sondir experiment, the formula
used is:
Local Friction
Decrease the formula:
→ σ = P / A, broad conical tip = 10 cm2
→ σ = P / 10
Reading → 1: 10 C = P
Reading 2: 10 (C
+ F) = P
→ friction = 10 (C + F) -10C
=
10F
→ area bikonus = 100 cm2
→ local friction (qs) = 10F / 100 = 0.1f
Where :
qs = local friction (kg / cm2)
C = cone resistantce, the first reading
(kg / cm2)
(C + F) = total resistance, the second
reading (kg / cm2)
Friction (barriers attached)
Because the barrier is observed every
depth of 20 cm, then
→ HL (F) = 0.1f x 20 = 2F = 20 qs
friction = 20 qs
Friction ratio
fr = qs / C x 100%
dimana:fr = friction ratio (%)
qs = local friction (%)
C = cone resistant (kg / cm2)