Our services - Offshore Geotechnical Investigation
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
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).
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.
Bulk (wet) density and dry density of various undisturbed soil samples will be found out as per IS: 2720.
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.
The co efficient of permeability of the soil samples will be determined as per IS: 2720 (Part XVII).
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.