Purpose of these boreholes shall be to determine the character, thickness and stratification of the
subsurface material, the relative density and permeability of granular materials, coring of rock and
such other data as may be required by the Engineer to determine the adequacy of the subsurface
material.

a. Depth of Boreholes

Depth of such boreholes and the depth at which core samples shall be taken shall be as directed by
the Engineer.

The  depth  of  the  boreholes  shall  be  determined  according  to  the  type  and  characteristics  of  the
subsurface  soil.  If  no  rock  is  encountered,  boreholes  shall  be  driven  to  a  depth  of  20  metres  in
predominantly gravelly-sandy-silty soils and to 30 metres in soft clay soils or soils with a low bearing
capacity where piling may be required, all in accordance with the directions and to the satisfaction
of  the  Engineer.  If  rock  is  encountered  before  reaching  the  above  depths,  the  borehole  shall
penetrate  at  least  10  metres  in  the  rock.  If  the  thickness  of  the  rock  is  less  than  10  metres,  the
borehole shall be continued as specified above and/or as directed by the Engineer.

b. Drilling of Boreholes

Boreholes or test borings shall be advanced between sampling intervals by driving a steel casing to
such depth below the ground surface. Casing diameter shall be as required to facilitate removal of
the soil sampling or rock coring that is required.

Boreholes  shall  be  augered  or  core  drilled  as  directed  by  the  Engineer.  Augered  boreholes  shall
comply with the requirements of ASTM D1452 and as specified herein. Core drilled boreholes shall
comply  with  ASTM  D2113  with  double  tube,  swivel-type,  M-design  core  barrels  and  as  specified
herein.  Casing at boreholes shall be NX size, with outside diameter of 89 mm and inside diameter
of 76.2 mm.

The boring shall be performed with continuous coring and the cores extracted shall be carefully kept
in proper core boxes so that the lithology can be recorded as accurately as possible. A preliminary
description of the core shall be made when it is extracted. Then these descriptions, together with
technical operational details shall be entered in the daily log which shall be available for inspection
by the Engineer at all times.

c. Borehole Equipment and Methods

Method and the equipment to be used for advancing the borehole shall be submitted by the
Contractor to the Engineer for approval. Casing shall be driven without the use of wash water unless
the Engineer specifically approves simultaneous washing and driving. Washing, spudding or drilling
ahead of the casing will not be permitted.

Between the depth intervals at which sampling is accomplished as hereinafter specified, loose
material within the casing shall be removed by the usual wash pipe method or other suitable means.
No downward directed jets will be permitted. Casing shall remain in the hole until the Engineer
authorizes its removal.

To prevent caving and mixing strata, casing or drilling mud material (bentonite) shall be used when
boring through any stratus which is not sufficiently cohesive to stand firmly without it.

Use of drilling mud to stabilize a borehole will be permitted only if the Engineer deems it is not
detrimental to pumping tests or groundwater observations.

d. In-Situ Testing and Sampling

Standard Penetration Tests (S.P.T.) is to be performed during the course of the boring at 1.0m
intervals or at every change of stratum.

Pocket penetrometer and/or vane test measurements shall be performed on all suitable cohesive
samples immediately after their sampling and before waxing.

Disturbed samples shall be taken from the top of each stratum from the material contained within
the standard penetration tool after the S.P.T. has been carried out, and from the cutting shoe of the

undisturbed sampler after the undisturbed samples have been taken. Each soil samples shall be
stores in a container of glass, plastic or other approved material, fitted with an airtight cover and
waxed immediately being taken from the boreholes. Each container shall be numbered and labelled
in such a way that the sample can be easily be identified with the boreholes, the soil stratum, the
depth from which it was taken and the date on which it was taken

Undisturbed samples should be taken in cohesive soils including mixed soils. Undisturbed samples
shall be taken from the most significant beds using appropriate means. The internal diameter of the
sampler shall be about 10cm and the useful length at least 50cm. The samplers shall be in good
condition and therefore shall be no signs of oxidation on the inner walls or damage to the base.

After the samples have been taken the ends shall be coated with wax, after having removed the
loose material. The containers shall then be sealed and clearly marked as specified for the disturbed
samples. A careful description shall be made of the undisturbed samples in the laboratory when
they are extracted from the container and before starting the required laboratory testing.

Samples and rock cores, immediately upon recovery, shall be placed in containers as approved by
the Engineer, identified as specified herein and delivered to the Site Laboratory included under
Section 1.19.7 of Chapter 1, General Requirement, of these Standard Specifications.

Each sample or rock core shall be identified and include the following information:

1. Location of borehole.

2. Date when sample was taken.

3. Boring number.

4. Surface elevation.

5. Name of driller.

6. Description and length of casing, if any.

7. Depth of bottom of boring.

8. Depth from which the sample or rock core was taken.

Testing of all samples and rock cores will be performed by the Engineer in the Site Laboratories.
Contractor shall furnish the Engineer with all pertinent data as may be required relative to the sample
so as to aid the Engineer in his testing program.

e. Water Levels

All water levels encountered in the boreholes shall be recorded and a check shall be made of the
static level after boring has been completed.

f. Borehole Logs

Boreholes logs shall be supplied to the Engineer as soon as possible after the borings have been
completed. They shall be in such a form as to indicate the location relative to any of the reference
points,  the  description  and  thickness  of  each  type  of  soil,  the  level  of  the  lower  contact  of  each
stratum  relative  to  the  said  level,  the  level  of  the  water  table  if  any,  and  the  position  and  record
number of every sample taken. The records are to be written in English and the descriptions of the
layers have to be in accordance with the International Standards. Furthermore, the records shall
include the results of standard penetration tests and of pocket penetrometer and/or vane tests and
rock core descriptions (total core recovery, solid core recovery and rock quality designation).

The site investigation works shall not be regarded as complete until all boreholes logs have been
submitted to the Engineer and approved by him.

g. Laboratory Tests

As a minimum, the following laboratory tests are to be carried out:

For disturbed samples:

•

Grading and Atterberg Limits (LL and PL) on representative samples from each

borehole as requested by the Engineer.

ii.

For undisturbed samples:

•

Grading by sieves and or by sedimentation, Atterberg Limits (LL and PL), Natural

Moisture Content and Bulk Density on all samples.

•

Consolidated undrained triaxial test (3 tests at different confining pressures on three

1-1/2" diameter specimens from each sample) on samples selected by the Engineer.

•

Oedometer consolidation tests on samples selected by the Engineer.

iii.

Unconfined compression tests on rock samples.

iv.

Corrosion effect on concrete of water and soils.

The results of the tests shall be given to the Engineer on approved forms. All measurements shall
be expressed in the decimal system.

The above laboratory tests provide a general guideline. Additional testing or elimination of some
tests may be requested by the Engineer

h. Final Reports

On completion of all laboratory testing a final report in triplicate shall be submitted to the Engineer.

This final report shall include a generalized subsoil profile and all borehole logs, soil identification,
in-situ and laboratory testing, observations and recommendations on the type of foundation and on
safe bearing capacity of the foundation soils and where piles are advised recommendations on their
safe bearing capacity.

2.2

Clearing and Grubbing

2.2.1

Description

This section describes clearing of the site, grubbing, and removal of topsoil necessary for
construction of the work covered by the Contract, in accordance with these specifications.

2.2.2

Construction Requirements

No clearing and grubbing shall be performed unless approved by the Engineer. Contractor shall take
all necessary precautions to prevent damage to structures and other private or public property.

Any unauthorised damage to, or interference with, private or public property, including trees, shall
be repaired to the satisfaction of the Engineer and the owner, at the Contractor’s sole expense.

2.2.2.1

Areas to be Cleared, Grubbed, and Removed of Topsoil

Areas to be cleared, grubbed, and removed of topsoil shall be in accordance with the particular
specifications and Contract plans, or as directed by the Engineer. In general, clearing and grubbing
shall be performed to 3 m outside the top of the fill slope and 3 m outside the top of the cut slope, to
include the following areas:

1. To be excavated, including areas staked for slope treatment

2. Where utility, drainage, and subdrainage trenches shall be dug, unsuitable material

removed, or structures built

3. Upon which embankments shall be placed

4. Wherever road, parking, and pedestrian pavement is to be placed

No trees that fall between the worksite and the limits of clearing and grubbing shall be removed or
damaged without the written authorisation of the concerned authority. Contractor shall submit shop
drawings, depicting the existing trees within the limits of the woks, clearly indicating those to be
removed and those to be retained, for the Engineer’s approval and as per the tree removal
management plan as may be contained in the Contract Documents. Individual trees designated by
the Engineer shall be left standing and uninjured.

Content .. 1 2 ..

///////////////////////////////////////