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MACKINTOSH PROBE TEST

Mackintosh Probe is usually used in preliminary soil investigation to acquire the untrained shear strength (directly through correlations) and consistency of the subsoil layering for very soft soils, sew et. Al (2000). Therefore, the application of this tool is very important to the construction world as it affects the whole construction of the structure.

 There are many shapes and models of the Mackintosh Probe but this research will be using the same model as Fakher et. Al (2005) that consists of a 27.94 mm diameter cone with a 30o –apex angle; 12.7 mm diameter solid rods and a 4.5kg dead weight with a standard drop height of 300mm as illustrated in Figure 49.

The usage of the Mackintosh Probe is very easy and the tools themselves are light in weight but it is also a boring tool to be used. As quoted by Fakher et al. (2006), it is a tool that is much faster and cheaper but boring, especially when the depth of exploration is moderate and below ground is a soft or loose investigation. From a human nature perspective, the user tends to make an error along the procesof the investigation because of the tireless feeling.



Figure: Mackintosh Probe


Figure: Mackintosh Probe in site

 

The procedure of the old Mackintosh Probe is as follows:

o  Equipment for the test is assembled. The cone diameter is measured in the SI unit.

o  The boring rods and hammer are joint using rod coupling. Grease is swept up for easy dissembles later.

o  Distance of 0.3 m is measured and marked on the rod starting from the tip of the cone.

o  The equipment is set up on the ground.

o  The hammer is pulled up until it reached the maximum. The hammer is dropped freely to drive the cone into the soil.

o  The sum of the number of blows for each 0.3m penetration is recorded in the data sheet.

o  The rod will continuously joint until :

§  The blow is more than 400 for 0.3m penetration.

§  The depth reached 15m

o Pull the rods using lifting tools after the penetration reached the requirement.

The equipment is dissembled and cleaned before storing


Figure: Mackintosh Probe test

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