JKR/ MACKINTOSH PROBE

INTRODUCTION

JKR/ MACKINTOSH PROBE

•The Mackintosh Probe is a lightweight and portable penetrometer. It is a considerably faster and cheaper tool than boring equipment especially when the depth of exploration is moderate and the soils under investigation are soft or loose• Mackintosh Probe which has 30° cone penetrometer while JKR Probes has 60° cone penetrometer.

• Based on the principles stated by HUARSLEV (1948) for drive rods for soundings and sampling and recommended methods for static and dynamics soundings by Europeans groups and subcommittee (1968).

• The rods consist of 16mm diameter High Yield Steel each of length approximately 120cm. Then the rods are connected to each other by 25mm outer diameter couplings.

Coupling = provide the lateral supports to the rods to prevent buckling during driving the rods.

• Driving is performed with a small hammer of 5kg and falling vertically though a fixed height of 30cm along a guide a rod.

• The total numbers of blows required for the pointer to penetrate a distance of 30cm is recorded and used as a measure of the consistency of cohesive soil and the packing of granular soil.

AIMS

For every in-situ or laboratory test that had been carried out must have an aim or an objective. The objectives of the JKR/Machintosh Probe

Test are:

Collecting a disturbed soil sample for grain size analysis and soil classification.

Determine the sub-surface stratigraphy and identify materials present.

Evaluate soil density and in-situ stress condition.

Estimate geotechnical parameters.

ADVANTAGES

• Light and easy user.• Does not need skill worker.• Economical.• Provides a disturbed soil sample for moisture

content determination.• Faster and cheaper tools

DISADVANTAGES

• Contribute to human error. -wrong counting• Low impact energy. -only can penetrated in shallow soil (limited depth) • Unable to penetrated into medium strength

soil and gravelly ground.

PROCEDURE

1. Equipments for the test are assembled. The cone diameter is measured in SI unit.2. The boring rods and hammer are joint using the rod coupling. Grease is sweep up for an easy dissembles later.3. Distance of 0.3 m is measured and marked on the rod start from the tip of the cone.4. The equipment is set up on the ground.5. The hammer is pulled until it reached the maximum. The hammer is dropped freely to driven the cone into the soils.6. The sum of the number of blows for penetration of 0.3 m is recorded in the data sheet.

7. The hammer is taken off on the last 0.3 m of each rod and joined the existing rod with another rod and lastly the hammer. The blow is continued and stopped when:· The blow is more than 400 for 0.3 m penetration· The depth reached 15 m8. Pull the rods using lifting tools after the penetration reached the requirement.9. The equipment is dissembled and cleaned before storing.

FIGURES

FIGURES

• Presented by : Hilmi bin Awaludin – 2011985059Nur Suryana binti Mohd Sutarzi – 2011527513Mohd Amirul Haziq bin Ratuah – 2011387721