1. INTRODUCTION
This method of testing covers the determination
in-situ of the density of natural or compacted fine and medium-grained soils in
which a 115mm diameter sand-pouring cylinder is used in conjunction with
replacement sand.
2. OBJECTIVE
The purpose of testing is to determine the
percentage (%) of compaction on every layer of filling. The test result will be
compared to the specification requirement, if the result is the same or more
than specification requirement, the related filling layer is accepted, and the
next layer shall proceed. If the result does not achieve the specification
requirement, the related layer needs to be rectified, and re-testing is needed
until the result is satisfactory.
2.1 Preparatory Works
This work shall be carried out accordance: -
a) Standard code of practice (refer to BS 1377 : Part 9 : 1990 : 2.1)
b) Before starting any work or testing, contractor to submit method statement of FDT and to be approved by consultant.
c) Contractor must follow any requirement from Client and Consultant.
d)
At any work, Contractor must follow instruction from Consultant or and
also By-Laws of Local Authorities approval and this approval must follow the
construction drawing.
3. SCOPE OF WORKS
Field density test will be carried out on every
layer of filling. The proposed method of field density test to the compacted
soil is by Sand Replacement Method or also known as Sand Cone Method. The
filling depth is approximately 500mm un-compacted per layer. Testing will be
carried out at 100m interval for road or as per Consultant Representative
Instruction according to the specification requirement.
4. REFERENCE
BS 1377 : Part 9 : 1990 : 2.1
5. SPECIFICATION REQUIREMENT
All layers of filling are to be compacted to 90%
compaction and 95% on final layer.
6. APPARATUS
a) 115mm internal diameter sand-pouring cylinder.
b) A metal tray about 280mm square and about 40mm deep with a 100mm diameter hole in the centre
c) Balance, readable to 0.01g
d) Material. The replacement sand shall be clean closely graded silica sand which provides a bulk density that is reasonably consistent. The grading of the sand shall be such that 100% passes a 600mm test sieve and 100% is retained on the 63mm test sieve.
e) Suitable tools for excavating holes in soils, e.g. chisel, bent spoon dibber and a scraper tool to make a level surface.
f) Tool kits – Hammer, chisel, iron nail, brush, measuring tape & plastic beg
g)
Apparatus for moisture content determination as specified is BS 1377 :
Part 2 : 1990
7. WORKING PROCEDURE
At Field:
a) Consultant to confirm the area of soil to be tested.
b) Once the location is confirmed, expose a flat area with approximately 450mm square of soil to be tested and trim it down to a level surface.
c) Brush away any loose extraneous material, preferably with the aid of the scraper tool. Lay the metal tray on the prepared surface. Use iron nail to fix the metal tray on the position in order to avoid any movement. Please refer Figure 1 for the illustration.
d) Use tool kits, e.g. chisel to excavate a round hole, approximately 100mm in diameter and 150mm deep.
e) Put the excavated soil sample into airtight plastic begs to prevent loss of moisture content.
f) The pouring cylinder will then be place in position over the excavated hole. Fill the pouring cylinder with 3000g Calibrated Sand. Open the shutter and allow sand to run out. Ensure that the cylinder and the surrounding area not vibrate. Please refer to Figure 2 for the illustration.
g) Close the shutter when no further movement of the sand. Remove the cylinder carefully and collect the sand.
h)
No FDT will be conducted if rain had occurred less than 48 hours.
However, special request will be considered as per site condition.
At Laboratory:
a) Information gathered shall be calculated to determine the percentage (%) of compaction.
b)
The value of ‘Un-compacted Bulk Density’ of Calibrated Sand to be used
in the calculation.
8
SAFETY AND ENVIRONMENTAL ISSUE
8.1 Safety
8.1.1. All workers shall provide with PPE (Personal Protective Equipment) and shall be worn every time they are entering the site. Safety Supervisor shall ensure all the workers wear all the safety equipment provided.
8.1.2. Safety Supervisor shall ensure that the activity shall ensure that activity shall carried out in a safe manner.
8.1.3. All workers shall fully support and actively participate in all safety related activities and comply with all practicable safety measures.
8.1.4. All workers shall be advised to report any accident or injury to supervisor and proper treatment to be obtained.
8.1.5.
The safety supervisor shall ensure that workers understand the safety
regulations and explain in detail in particular hazards, where the workers are
working and the precaution to be taken to ensure their safety.
8.2 Environmental
8.2.1 All workers shall ensure that all tools and equipment machinery are in good condition to avoid any oil leakage that could harm to environment (if any).
8.2.2 Water from particular construction area shall be diverted into proper drain which is eventually empties into silt trap.
8.2.3
Domestic and construction waste from construction area must be collected
into centralized garbage bin and disposed at the designated area.
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