Conclusion

JKR Probe Mackintosh is can be used to determine the thickness of unsuitable material to be

removed and also for preliminary design of embankments, limited about 15m and must be record

no. of blows/ft. then correlates to established chart to determine bearing capacity of soil.

Mackintosh probe which has 30°cone penetrometer while JKR Probes has 60° cone

 penetrometer. This is a light dynamic test and the cone is driven directly into the soil by driving a

hammer 5kg. Weight dropping through a free height of 280mm. the probe I unable to penetrate

into medium strength soil and gravelly ground.

Discussion

One of the major problems associated with the foundation construction phase is rock excavation.

In general, rock excavation is much more expensive than soil excavation. Excavation of rock by

 blasting is not only expensive but may not be accepted if it is likely to induce adverse effect on

nearby structures or general environmental conditions such as water supply, noise, etc. Field

investigation for detecting the presence of rock in project site is necessary because of the

following possible reasons:

1. That the foundation rests directly on rock

2. Excavation of the rock is necessary during construction (i.e. the cost for rock

excavation may be many times that for ordinary soil)

3. The rock formation may be subject to weathering effects (e.g. disintegration,

expansion) during construction

4. Variations in the rock stratum (e.g. flaws or fractures, variation in characteristics and

formations, elevations)