Offshore Geotechnical Investigation involves Land & Marine boring
through soil & rock. In-situ test and sampling of soil, water and
rock. Field supervision and Consultancy for large and important
geotechnical investigation. Soil tests for Road Projects.
Corrosively study of underground pipeline routes etc.
We Mars
Synergy Geotech Pvt. Ltd. under go the following test for Offshore
Geotechnical Investigation:
Field Tests for Geotechnical
Investigation
Boring and SPT Tests
Bore holes depths are varying from place to place, at locations
indicated in the drawings or as directed by the Engineer-in-Charge.
Boring shall be carried out with a 150 mm size diameter casing by
shell and auger, percussion boring shall be resorted to where a
difficult stratum is encountered. Bentonite slurry or mud
circulation process can also be used if permitted.
However, for those bore holes where water samples are to be
collected (if required) for chemical analysis or field permeability
tests are to be conducted, bentonite slurry or mud circulation
method will not be used. Generally we indicate equipment and method
is going to adopt for the bore holes.
If boring becomes difficult before the specified bore hole
termination depth, then chiseling shall be resorted to for the
eventuality of any local boulder being met with till the rate of
progress is less than 50mm penetration in 10 minutes and rock strata
is indicated.
Where rock strata are met with, drilling in rock shall be carried
out to a minimum depth of 3 meters in rock or to a depth where core
recovery is above 85%. Rotary rock drilling shall be carried out
with Tungsten Carbide / Diamond Core bits of NX size with the next
lower size used in case of difficulty in drilling further. From the
bore holes, undisturbed soil samples of 75mm diameter shall be taken
at every change of stratum or at an interval of around every three
meters from ground level to bore hole termination depth.
However, at least three Undisturbed samples will be taken within
the first five meters depth from ground level. Disturbed samples as
and where undisturbed samples are not possible are taken for tests.
Standard penetration test will be conducted as per IS: 2131 in the
bore holes at every change of stratum or at an interval of around
every 1.5 meters from ground level to termination depth. All
disturbed and undisturbed soil samples will be protected from the
atmosphere. Samples will be labeled and handled as per IS: 2132 and
transported to our laboratory.
All field tests will be carried out in the presence of the
Engineer-in-Charge or his authorized representative, daily field log
data duly signed by the Engineer-in-Charge's representative will be
submitted to the Engineer-in-Charge. The field log data sheet will
have each test location, colour and nature of soil in each strata of
a borehole and depth of water table from ground level (if
encountered while boring).
Laboratory Testing
All laboratory tests will be carried out in our well-equipped
laboratory under the supervision of our qualified and experienced
personnel.
After completion of field work but before commencement of
laboratory testing, we will submit a programme for laboratory tests
required for the various soil, rock and water samples. The tests
will be commenced only after approval of programme from the client
and the samples tested as per relevant IS Codes.
Density
Bulk (wet) density and dry density of various undisturbed soil
samples will be found out as per IS: 2720.
Moisture Content
Natural moisture content of the soil samples will be determined as
per IS: 2720 Part II.
Optimum Moisture Content (OMC)
Optimum Moisture Content to obtain maximum dry density will be
determined using Standard Proctor Test. A curve will be plotted
between penetration resistance and water content.
Particle Size Analysis
Particle size analysis of soil samples will be carried out by sieve
analysis and hydrometer analysis for classification and
identification of soil as per IS: 1498.
The porosity of soil and the uniformity co efficient will also be
determined.
Permeability
The co efficient of permeability of the soil samples will be
determined as per IS: 2720 (Part XVII).
Shear Test
Triaxial shear tests will be carried out in a standard triaxial
shear machine on undisturbed soil samples to determine the values of
cohesion and angle of internal friction of soil as per IS: 2720
(Part XI) and IS: 2720 (Part XII).
Direct shear will be carried out as per IS: 2720 (Part XIII):
1986 in a standard direct shear box on an undisturbed soil sample to
determine the strength parameters (C & ?) of the soil sample.
California Bearing Ratio (CBR) Test
California bearing Ratio (CBR) Test will be carried out as per IS:
2720 (Part - XVI) - 1979 on undisturbed and remolded soil samples
collected from field. The samples will be collected from a depth of
0.5m below natural ground level. Load - Penetration curve shall be
plotted with proper correction and test data shall be produced in
Proforma given in relevant IS Code.
Environmental Impact Assessment
Environmental impact assessment is highly essential in the present
scenario since the rapid urbanization and industrialization tends to
change the balancing factors of ecology.
