KONSERVASI EKSITU DI TAMAN NASIONAL WASUR DAN PELESTARIAN INSITU DI TAMAN NASIONAL UJUNG KULON SERTA DEPLISI
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INTRODUCTION
In-situ tests mean any testing that is done in field with direct result which difficult to obtain undisturbed of sample, additionally to determine parameters at real condition such as bearing capacity of soil, water table, setting depth and many more. One of the most common Geotechnical in-situ is JKR Probe Test. JKR Probe test is light dynamic penetrometer used to in preliminary site investigation to find the undrained shear strength (indirectly through correlations) and consistency of the subsoil. This method is also effective identifying localized soft or weak material or slip plane. However, the major limitation of the method is shallow depth. The JKR probe is a lightweight and portable penetrometer. Mackintosh probe which is has 30◦ while JKR probe has 60◦ cone penetration. This is a light dynamic test and the cone is driven directly into the soil by driving hammer by free hand. It is considerably faster and cheaper tool that boring equipment especially when depth of exploration is moderate and the soil under investigate are soft and loose.
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OBJECTIVE 1) 2) 3) 4) 5)
To determine soil classification. To determine physical properties of soil. Learn how to handle in-situ probe mackintosh test. Collect data the number of hammer drop per 30 cm of depth. Sketch the graph to determine classification of soil.
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TESTING LOCATION LAYOUT PLAN
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APPARATUS NO 1.
PICTURE A series of 1.2m steel bar / rod
2.
A hammer which attached to bar head
3.
Measuring tape
NAME OF APPARATUS
4
4.
Marking chalk
5.
Wire brush
6.
Oil grease spray
PROCEDURE 5
NO 1.
PROCEDURE Select the location and site clearing work:
2.
DETAIL WORK
Study the work area first to known the type of soil before select the location. (it could be clay or sandy) Clear the top of grass by using hoe with square per area (0.5m x 0.5m)
Installation the equipment.
Take the equipment. Every rod is clear by wire brush. The rod and hammer was joined
using the rod coupling. Spray the oil grease at each coupling road for an easy
dissembles latter. Every rod is marked by chalk every 0.30 m.
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3.
Hammer work:
4.
The equipment was set up vertically on the ground. Attached the hammer in the bar head. Start applying hammer drop, by raises the hammer until the top hammer touching the guard steel. The hammer was dropped freely to driven the cone into the soils. Count the hammer drop until the bar penetrate 0.30m as marked in the probe rod. As the penetration rod reach 1.2m, the second rod should be attached to pervious bar. The blow will stop when the blow count is more than 400 blows for 0.3m penetration. After the 3rd rod was successfully driven into soil, the rod was pulled out using the lifting tool. The equipment was dissembled and cleaned before storing.
Collect data:
The sum of the number of blows for each penetration of 0.30m
was recorded in data sheet. Plot the blow hammer in every 0.30 against depth of penetration.
No of Blow / 0.3m 146 181 152 120 95 36 20 23 25 15
Prepared by:
Verified by:
Name:
Name:
1) MUHAMMAD REDZUAN BIN
1) PUAN ZAHARAH BIN MAMAT
ABDUL RAHMAN. 2) MUHAMMAD ZAHRIN BIN KASIM @ KASSIM. 3) MOHAMMAD ZAKI IBRAHIM BIN SANUSI. Date :
Date :
DISCUSSION 8
JKR PROBE MACKINTOSH TEST: In our observation this test is carried out in preliminary site investigation before construction project is initial to get determination of shallow bedrock profile. In additional, the advantages of this testing is the small size and lightweight device that causes the work easily to handle and quick to get direct result at any places. The disadvantages is low impact energy because only penetrated in shallow soil (limited depth). Human errors are also prone in this method such as wrong counting, non-consistent drop height and exerting force to the drop hammer giving misleading results. This error is due because the human force is difference each other’s. From our recommendation, we must use one-person human force to get consistent hammer drop. When using of light dynamic penetrometer (JKR or Mackintosh) some precautionary measures to prevent errors in testing. Firstly, drop the hammer should be a free fall and consistent drop hammer. Secondly, components and apparatus properly washed and oiled to easily assembled.
CONCLUSION 9
From the JKR probe result data form we are plot the graph the number of blow / 0.3m against the depth. We are concluding the graph is divide into 3 stages of soil of type category according the properties of soil. Firstly, is hard soil layer category. The soil colour is red. This is preliminary soil when penetrate the rod into soil ground. From the graph we known the depth of hard layer is between from 0.3 m to 0.6 m. The number is blow is increase from 146 to 181 because its contain rock and boulder that need more human force and longer time to penetrate the into soil. The low moisture contains also influence the number of blow at this layer because this soil layer is dry. The consistency soil second layer is very stiff. Finger pressure barely dents soil but cracks under significant pressure. From the graph the depth is between from 0.6 m to 1.5 m and the blow is decrease from 181 to 95. From the rod probe we can see the soil colour is yellowish and more easy to penetrate than hard layer because contain sand and gravel. The consistency soil third layer is very soft that soil flows between fingers when fist is closed. This layer is take less time to penetrate because this layer is overall containing clay type soil that more easily to penetrate. From our observation we can see the brown dark colour at rod and cone penetrometer.
REFERENCE 10
1. Site Investigation (DCC 3013), Edition 2016, Kolej Kemahiran Tinggi Mara Sri Gading.
