Proba Mackintuihhh

1.0 INTRODUCTION

A thorough soil investigation is required before a construction project begins. This is important to assure the safety of the construction, the residence and the surroundings. The main reason for a soil investigation is to identify the type of soil for each soil layer underneath the foundation of the construction to be built, soil strength and moisture content of the soil. There are various types of soil investigation methods that are conducted on construction sites or in the civil engineering laboratories. There are determination of soil bearing capacity and moisture content. Soil bearing capacity is the ability of soil to support weight from the foundation of a structure is known as the bearing capacity of soil. The test used to determine bearing capacity of soil is Mackintosh Probe Test.

2.0 THEORY

The main purpose of the test is to provide an indication of the relative density of granular deposits, such as sands and gravels from which it is virtually impossible to obtain undisturbed samples. The great merit of the test, and the main reason for its widespread use is that it is simple and inexpensive. The soil strength parameters which can be inferred are approximate, but may give a useful guide in ground conditions where it may not be possible to obtain borehole samples of adequate quality like gravels, sands, silts, clay containing sand or gravel and weak rock. The usefulness of SPT results depends on the soil type, with fine grained sands giving the most useful results, with coarser sands and silty sands giving reasonably useful results, and clays and gravelly soils yielding results which may be very poorly representative of the true soil conditions. This test method provides a disturbed soil sample for

moisture content

determination, for identification and classification purposes, and for laboratory tests appropriate for soil obtained from a sampler that will produce large shear strain disturbance in the sample. Soil deposits containing gravels, cobbles, or boulders typically result in penetration refusal and damage to the equipment. This test method is used extensively in a great variety of geotechnical exploration projects. Many local correlations and widely published correlations which relate blow count, or N-value, and the engineering behavior of earthworks and foundations are available. Formula Cone resistance (qc)

friction resistance(fs)

Blow x Weight of hammer

Blow x Weight of hammer

Area of cone

Area of friction

Friction ratio (Fr) Fs x 100% qc

3.0 OBJECTIVES The end of laboratory test, students will capable to : 1. 2. 3. 4.

Collecting a disturbed soil sample for grain- size analysis and soil classification. Determine sub-surface stratigraphy and identify materials present Evaluate soil density and in-situ stress conditions Estimate geotechnical parameters.

4.0 APPARATUS AND SUPPLIES

Boring rod

Penetration cone

Road couplings

Lifting tool

Hammer

Brush

Pail

Ruler

Liquid paper( for marking)

5.0 PROCEDURE

1. Prepare and set up the apparatus used for probe mackintosh test such as, boring rod, coupling, penetration cone, hammer, lifting tool, wrench, and ruler/measuring tape. 2. Joint the penetration cone with the boring rod. Before that, make sure that the rod be cleaned from any tiny substances with brush. 3. Measure a 0.3m, then 0.6m, 0.9 and so on rod start from the tip of cone by using ruler and marked it with liquid paper. 4. Apply the rod coupling to the boring rod to join the rod with 5kg hammer. 5. Then, pulled the hammer until reach the maximum level so that cone will be driven into soil together with the boring rod by falling the hammer freely. 6. Record the sum of the number of blow for each penetration for every 0.3m in the data sheet.(0.3m then 0.6m,0.9m and so on.) 7. On the last 0.3m of each boring rod, take off the hammer and joint existing rod with another boring rod. Then joint the hammer again. 8. Continued the blow and stop when blows increased 400 for a 0.3m penetration and the depth of soil penetration reach 15metre. 9. Finally, after the last six boring rod penetrate into the soil, pulled the entire boring rod using the lifting tool. Make sure that you do not turn around the rod. 10. Clean all the apparatus used and kept or stored in proper place.

6.0 RESULT

7.0 CONCLUSION

When we do this experiment, we managed to completed in 2 hour. When the experiment is conducted, we learn how the probe mackintosh is conduct when the penetration of the boring rod penetrate to the ground. There were 6 boring rod used in this experiment. This experiment is conducted similar to piling work at construction site. We get the data and tabulate it into form. From that we learn how to calculate the cone resistance, friction resistance and friction area. After the calculation is done, we plotted the graph from the calculation. The result is this soil for initial 0.3 m are 34 blows where this blows determined that this soil cover moist fine sand, or sand with large amount of clay varying from soft to firm consistency. After that, at 0.6m to 7.2 m, the number of blows range between 67 to 180 where this shoe the soil are moist sand and sandy clay varying from firm to vary hard consistency.

8.0 DISCUSSION

1. What is the difference between Standard Penetration Test (SPT) and Cone Penetration Test (CPT). Cone penetration test (CPT)

Standard penetration test (SPT)

Determine the property of bearing

Provide an indication of the relative

capacity

density of granular deposits, such as sands and gravels from which it is virtually impossible to obtain undisturbed samples.

One of the most used and accepted in

Simple and inexpensive

situ test methods for soil investigations worldwide. Consists of pushing an intrumented

The soil strength parameters which can

cone, with the tip facing down, into the

be inferred are approximately.

ground at the controlled rate 2cm/s

2. List out the advantage and disadvantage of cone penetration test (CPT) Advantage

Disadvantage

Easy to handle

Expensive

Automatic

Using to much machine

Fast method

3. State out the different between Probe Mackintosh and Probe JKR Probe mackintosh

Probe JKR