Results of geophysical method is reliable in geotechnical site characterization only when you calibrate it with  data of borehole from near by area

I agree with the answer, wells are the most accurate dotted data,so it is necessary to correlate the results of the geophysical surveys with the wells. Performing geophysical measurements is economically acceptable. These methods are classified as non-destructive or minimally destructive methods. They are often used for investigation and determination of soil properties, for prediction of the mechanical behavior under certain conditions and for controlling the performance of construction work. In the framework of geotechnical investigation works, geophysical seismic measurements are often performed. From the results of geophysical seismic surveys are possible to determine: modul of soil deformation, density and porosity of the soil (assuming a specific density of the soil), a parameter of deformation under dynamic loads, the determination of the boundaries between different types of soil. Also, they are often used in the analysis of the state of the slope of the soil, for prediction of foundation soil subsidence of the ground, for testing the integrity of the piles, for investigation of the route of the tunnel, for the definition of the potential of liquefaction (SASW method) etc.

Dear Marija Podbojec ,

Thanks for your response.

Will you please share some literature where geophysical methods are being utilized for soil mechanical properties determination ?

'a parameter of deformation under dynamic loads, the determination of the boundaries between different types of soil' please provide some references...

Thanks 

Dear Yawar  Hussain,

   I fully agree with the earlier answers provided.  Some salient features of the 'geophysical methods' frequently used, are its non-invasive nature and the  optimization of the time required for these studies being undertaken in ambient field conditions with reasonably good precision and hence robust interpretation.  Hopefully I would be able to share some relevant literature as desired.

Dear Yawar Hussain,

Here is some literature:

1) Luna, R. and H. Jadi, "Determination of Dynamic Soil Properties Using Geophysical Methods," Proceedings of the First International Conference on the Application of Geophysical and NDT Methodologies to Transportation Facilities and Infrastructure, St. Louis, MO, December 2000

2) RIVAS - Railway Induced Vibration Abatement Solutions Collaborative project

"TEST PROCEDURES FOR THE DETERMINATION OF THE DYNAMIC SOIL CHARACTERISTICS"  November 2011

3) Massarsch K. R., "Deformation Properties of Stabilized Soil Columns", Proceedings, Intern. Conf. on Deep Mixing, Stockholm, May 2005

4) HSAI- YANG FANG, "Foundation Engineering Handbook" (Second Edition), New York, 1991, ISNB 978-1-4757-5271-7(eBook)

Thanks

Geophysical techniques only provide clues on desired engineering properties of geomaterials for geotechnical engineering. However, geophysical investigations require some forms of ground-truth in the form of test holes or wells for validation of its results.

Dear Yawar, some of the answers that I gave for questions with geophisical methods are also valid for geotechnical characterization with geophiscs.Namely, the geophisics is very useful but indirect methodology which can help in an indirect way, but it must be used parallel with some direct investigation methods to insure data for correlation.All previous answers are in this direction.

Dear Yawar,

It depends on the type of information you seek, depth to bedrock, elastic parameters, water content? As many have pointed out above, the method is indirect (expect for logging which is closer to groundtruth) so that the results will be dependant on the site conditions, survey design, resolution etc...

There are several paper which you can find related to the topic.

Kind regards,

Thanks all 

Especially useful to define the depth of soil (overburden) cover and finding the weakness / fault zones.

Actually the best practice is to narrow down  from geophysical investigation to geotecnical investigation, it always covers wide area in short time and less expensive but the accuracy and consistency  depends on experience of geophysicist 

Destructive methods like cross hole tests are more accurate, and non-destructive tests,as long as disturbance at site is low, those tests do give appropriate results. However I suggest atleast one cross hole test is essential to cross check the ndt tests such as SASW or MASW test. However passive tests...are not recommendable for design purpose, they are only meant for understanding the basic nature of shallow layers of the soil.

Precision varies based on method and application.  Some techniques such as ground penetrating radar (GPR) can be very precise based on scale, calibration, and target properties.  For instance, mapping rebar in concrete can be to within a couple cm or less. Scaling up to estimating depth to bedrock in areas with very little overburden (