SCOPE
OF WORK
The
scope of Soil investigation should be such as to clarify the soil conditions in
order that satisfactory and economical foundations can be designed and proposed
recommendations for suitable types of foundation and establishing the reliable
soil parameter based on the analysis of the geotechnical data.
These
investigations should be performed immediately after the Contract Award. The
Contractor should submit the investigations program to the Owner for approval.
The program approval does not relieve the Contractor from his obligation to
undertake additional investigations of the soil based on the Owner’s request,
and that may be the result of the soil investigation first report evaluation.
Investigation
and elaboration of reports on investigation results and structures foundations
conditions should be entrusted to an institution specialized for soil mechanics
and foundation. Such an institution and the Report should be approved of by the
Owner.
The
work shall include but not limited to the mobilization and demobilization,
transports and furnishing of all machines, equipment and installations
necessary to perform the works specified hereafter, such as drilling rigs,
rods, bits, casings, CPT, power generators, compressors, pumps, vehicles, cisterns
and all other matters deemed necessary by the Contractor to perform the
foreseen investigations as indicated in Book II, "Summary of Work"
and Book IIIA refers to "Civil and Architectural Requirements".
CODES
AND STANDARDS
The
Contractor shall comply with the requirements of Book II, "Codes and
Standards".
The
Codes and standards of the following organizations extracted from Book II,
"Codes and Standards" are specifically applicable to the design,
manufacture and testing of the work included in this specification.
ASTM
American Society for Testing and Materials
BS
British Standard
AASHTO
American Association of State Highway and Transportation Officials.
WORKS
EXECUTION
SCOPE
OF INVESTIGATION
The
following minimum of the investigations program is compulsory:
a.
22 bore‑holes on new site with total depth of 880 m
b.
15 static cone penetrations test on shore to the depth of 30 m in average.
c.
In each of the bore‑holes, undisturbed samples of soil shall be taken in 5.00 m
interval and minimum 1 (one) at each different layer, vane test and SPT test
shall be performed in 1.00 m interval.
d.
Testing laboratory for undisturbed and disturbed samples of soil properties.
CORE
DRILLING
PROCEDURE
Core
drilling will be carried out by rotational method with clear water flush or on
the request of the Owner without any flush at all.
Core
recovery is required on the entire length of all drillings. A minimum core
recovery of 90% is requested. Only material not altered or damaged by the
drilling process will be considered as “core“. Zones where SPT, vane tests or
undisturbed sampling performed are considered as zones with recovered core.
Cores
have to be handled carefully in order to prevent deformation or breaking.
DEPTH
Drilling
equipment must be able to perform bore holes to a depth of 50 m.
The
final depth of the bore hole, as well as the depth achieved with every core run
will be measured with the drill rods in accuracy of 5 cm.
If
a boring does not reach the required depth, an additional hole has to be
drilled and no compensation will be given for the abandoned hole.
The
Owner is entitled to change the length of borings based on geological features.
DIAMETERS
The
initial diameter shall have to be chosen by the Contractor. The final core
diameter should not be less than 54 mm.
In
order to allow proper telescoping, core barrels, bits and casing for several
diameters should be on the site.
OTHER
OBLIGATIONS TO THE CONTRACTOR
The
Contractor shall assist the Owner during core logging and for all other works
related to the preparation and supervision of the Contractor's work.
The
Contractor shall take colored picture of all cores. Two copies 9 x 13 cm and
the negative shall be handed over to the Owner.
Each
finished bore hole shall be marked by a concrete block cast in place, with a
minimum base dimension of 40 x 40 cm and a minimum height above ground surface
of 10 cm. The number of the bore holes has to be engraved in the concrete.
EQUIPMENT
Rigs
shall meet the following specifications :
-
Hydraulic or mechanical feed
‑
Transmission gear to adjust spindle speed (e.g. 60 to 300 rpm).
The
core barrels shall be in perfect, which guarantee the request core recovery.
The use of single ‑ tube core barrels is not allowed.
Diamond
bits and hardened steel bits in perfect condition from a well‑known manufacture
shall be used.
The
Contractor shall supply all necessary flush water for the execution of boring
and pertinent tests. Facilities for sedimentation and water reservoir of
adequate capacity may be necessary. Only clear water shall be used.The
Contractor shall establish the sequence of drilling and testing based on the
frequent requirements for the different bore hole tests to guarantee testing
and sampling in natural soil conditions and to allow for a reasonable drilling
progress. The sequence shall be approved by the Owner.
Core
boxes should be made of good and durable material and covered by a lid with
hinges.
The
inner length of a core box shall be 1 m and for each meter of bore hole one
meter of core box shall be foreseen. The end of each core, as well as other
pertinent information (e.g. core loss, extracted sample, etc) has to be made
immediately in the core boxes with indication of actual depth.
Inscriptions
on the boxes have to be punched into aluminum or plastic straps.
The
boxes must show the following indications on the inside of the lid :
-
Job site
-
Number of bore hole
-
Date of finishing the bore hole
-
Number of the box
-
Depth interval
The
boxes must show the following indications on the outer small side :
-
Job site
-
Number of bore holes
-
Number of the boxes
Core
boxes have to be stored in such a way that they are protected against rain and
sun.
STANDARD
PENETRATION TEST (SPT)
The
test shall be made according to the following standards :
ASTM
Designation D 1586 or BS 1377, Test 19.
The
extracted sample shall be packed and sealed in a plastic bag and placed in the
core box. It shall be labeled for identification with date, bore hole number,
depth and number of blows.
With
the sampler resting on the bottom of the hole, drive the sampler with blows
from the 140 pound hammer falling 75 cm until either 45 cm have been penetrated
or refusal (defined as 100 blows per 15 cm or less of penetration) has been
reached.
Standard
reporting shall give the number of blows for the first, second and third
penetration of 15 cm. If the number of blows for the first 15 cm would exceed
20, the penetration depth for the first, second and third 20 blows shall be
reported. Further more it shall be reported if the hammer is free chopping or
fixed by a rope‑
VANE
TEST
The
test shall be done according to the standard ASTM D 2573, AASHTO T223, BS
1377,T18 or another standard approved by the Owner.
To
allow for calibration it shall be performed just below the location of a SPT
test.
The
test shall be performed in such a way that the rods are isolated from the soil,
i.e. that no friction occurs between the rods and the soil.
The
maximum and residual value of torque and corresponding shear strength shall be
reported.
PERMEABILITY
TEST
If
there were any sandy layers of the subsoil, the permeability shall be measured
with the falling head test method.
The
test shall be performed where such a layer is encountered or as directed by the
Owner.
In
general, not more than 2 tests shall be performed in one sand layer and no test
shall be closer than 3 m to the next one.
Before
perform the test, the bottom of the bore hole shall be cleaned and the water
within the casing shall be clear. The ground‑water level at the time of the
test shall be registered.
For
the test, the casing shall be filled with clear water and the falling of the
head in function of time shall be measured. Registration time may be up to 20
minutes.
After
the test, the depth of the bore holes has to be controlled.
If
the casing is telescoped, special measures are needed to avoid water loss at
the level of diameter change.
The
record of tests shall include:
‑
depth of boring
-
depth of ground‑water level
-
duration of test
‑
diameter of casing at depth of casing and water level measurements
‑
array of data with time and fall of water level during test.
The
Contractor shall interpret the data and give the permeability of the measured
soil layer.
Data
and interpretation shall be handed over to the Owner on approved forms within
48 hours.
The
compensation for test is independent of the diameter of the depth below surface
where the tests were performed.
The
supply of the required water volume for flushing the hole and testing is
understood to be part of the test and the Contractor is not entitled to any
additional payment irrespective of the volume of water lost in preparation and
performance of the test.
SAMPLING
In
the course of the field investigations, 3 types of samples shall distinguish:
‑
Undisturbed soil samples
‑
Disturbed samples
‑
SPT‑samples
All
samples are taken from the drillings. Within counting the SPT‑ samples, one
sample shall be taken every in 1 m interval.
Undisturbed
soil samples are extracted from bore holes with a special instrument, as
defined in ASTM D 1587, in fine‑grained or cohesive soils.
The
instrument is subject to the Owner's approval.
Undisturbed
soil samples shall be taken in appropriate soils every 5 m interval or at
regular intervals, as directed by the Owner.
Disturbed
samples shall be of soil, taken from cores and packed and sealed in plastic
bags or plastic tubes. Number, type and size of these samples are directed by
the Owner.
All
samples shall be labeled. The label shall indicate the project, site, bore
hole, depth and date of extraction.
On
the site, the samples shall be stored in a special place sheltered from sun and
rain.
CONE
PENETRATION TEST (CPT)
CPT
equipment and testing procedure shall be in accordance with the recommended
standard, established by the subcommittee on Standardization of Penetration
Testing in Europe published i.e. in the Conference Papers of ICSMFE. Tokyo
1977, vol.3, pg.95 ff.
Deviations
from that standard shall be indicated in the test report and need to be
approved by the Owner.
Based
on the actual geological knowledge depth are envisaged for testing: 30 m.
The
test results shall be presented in a plot of cone resistance and‑total side
friction versus depth.
Additionally,
but not alternatively the Contractor may offer the measurement of the pore
water pressure versus depth. In this case the Contractor shall submit a
description of this equipment and indicate the price for such readings per
linear meter as an over item to the price of CPT.
The
test records shall be handed over to the Owner within 48 hours after test
performance.
They
shall also be integrated in the Final Report.
Such
payment includes also the set up of the test equipment at each location.
LABORATORY
TESTING
The
samples taken in the field shall be transported to the laboratory at least
every fortnight.
The
Contractor is then responsible for adequate storage, extraction, description
and preparation of each sample. All this work shall be included in the unit
prices of tests and no extra compensation is given for such work.
The
Contractor will receive, from the Owner, a test list indicating the tests to be
performed for each sample. If, for any reason, this test program can not be
followed, the Contractor shall immediately inform the Owner and furnish
reasons.
The
number of each test given is the minimum requirement.
Variations
from the given quantities may be directed by the Owner.
For
each test, the Contractor shall indicate the standard he will follow.
Deviations
from any standard or the use of other standards than the ones specified
hereafter need the written approval of the Owner.
The
following tests for soil properties shall be performed in accordance with ASTM
and/or AASHTO and/or BS standards. Test and data recording shall include:
§
Particle‑size analysis of soil, ASTM D422 or AASHTO T88 or BS1377.
§
Liquid limit of soil, ASTM D423 or AASHTO T89 or BS 1377.
§
Natural water content, ASTM D2216 or BS 1377.
§
Natural (moist) unit weight, BS 1377.
§
Specific gravity, ASTM D854 or AASHTO T100 or BS 1377.
§
Organic matter, ASTM C40 or ASTM T21 or BS 1377.
§
Permeability, ASTM D2434
§
Unconfined compression strength, ASTM D2166 or AASHTO T208 or BS 1377.
§
Consolidation, ASTM D2435 or AASHTO T216 or BS 1377
§
Triaxial shear strength, AASHTO T266 or BS 1377
§
Direct shear strength, AASHTO T236
REPORTS
DAILY
REPORTS ON FIELD WORK
The
driller will daily carry out a report, containing:
‑
Diameter and type of bit
‑
Diameter and depth of casing
‑
Rotation velocity
‑
Drilling pressure
‑
Total water losses
‑
Pressure of clear‑water flush, color of flush
‑
Depth and time interval of core runs
‑
Types of soil
‑
Water level in hole at beginning and at end of shift, intermediate measurements
‑
Any other pertinent information
The
form of the daily report is subject to the Owner's approval.
There
is no extra compensation for the daily reports.
FINAL
REPORT ON FIELD WORK
The
Final Report will obtain the following items:
Activity
time schedule of investigation program (table)
Layout
of the area where PLTU Kalimantan Selatan (2 x 65 MW) is to be constructed,
with structures locations indicated, and the positions of investigations shall
be carried out.
Drilling
equipment used by the Contractor on site (list)
Comments
on the performed work.
Drawings
of the bore logs.
Complete
data and interpretation for all field tests as SPT and permeability.
List
of all extracted samples (SPT, disturbed and undisturbed )
Logs
of CPT.
DRAFT
REPORT.
A
draft of the Final Report is subject to the Owner's approval. It shall be.
delivered not later than 1 week after termination of the field work.
PROGRESS
REPORT OF LABORATORY WORK.
Every
two weeks, the Contractor shall prepare and forward to the Owner one report
with the following features :
‑
Samples received
‑
Tests performed
-
Deviation from the test program
-
Comments on the test program and on the test result
-
An annex containing all test results of the given period
No
extra compensation is foreseen for the Progress Reports.
TEST
RECORD
All
forms for the test readings and interpretations shall be approved in advance by
the Owner. The Owner may also require additional forms or different plots.
FINAL
REPORT ON LABORATORY WORK
The
final report shall contain the following items:
a
sample list
a
list of performed tests
Summaries
of test results, arranged according to technical, geological or geotechnical
features all test results, readings, plots and interpretations.
The
Contractor shall first prepare a draft issue of the Final Report and submit it
to the Owner for approval. It shall be delivered not later than 4 weeks after
termination of the field works.
All
forms and reports shall be in English.
The
Contractor shall hand over 5 copies of the Final Reports to the Owner.
Furthermore shall provide to the Owner, the original of all text and data
sheets and a transparent copy of all drawings.
The
lump sums for reporting shall include all data collections, typing, copying,
interpretation, calculation, designing, drawings, reproducing, posting, as well
as all paper and other material and work necessary, to provide the required and
approved reports.
The
contract work is regarded to be terminated after the Owner has accepted in
writing, the draft of the Final Reports and after the Contractor has delivered
all originals and copies of the Final Reports in correspondence with the
accepted Draft Reports, as specified above.