CONE PENETRATION TEST

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)