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Integrating shear-wave seismic and Cone Penetration Testing to derive...

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Title Integrating shear-wave seismic and Cone Penetration Testing to derive laterally varying geotechnical information
Period 01 / 2003 - 99 / 2007
Status Completed
URL http://www.stw.nl/Projecten/D/dar/dar5761.htm
Research number OND1311112
Data Supplier website Stichting Technische Wetenschappen STW

Abstract

The most popular method to date to derive the depth distribution of soil strenth is Cone Penetration Test or CPT. Though CPT provides valuable information of soil strength, the information is 1-dimensional, i.e. restricted to the CPT borehole location. The shallow subsoil is infamous for its sharp lateral variability. There is no technology available now to provide objectively information of the lateral variation of the strenth and other important parameters of soil, and this results in large risks and frequent accidents. To address this problem, we propose the idea of a scientifically rigorous integration of high-resolution, seismic shear-wave reflections with the CPT data, based on an understanding of the underlying physics. Seismic shear waves are particularly sensitive to the mechanical properties of the soil. Seismic reflections have been used in oil industry to map subsurface structures or layer boundaries, but to derive from the amplitude of the seismic reflections the physical properties of the soil layers, such as an indication of the soil strength is a completely new idea. The main scientific challenge lies in the fact that seismic reflections address the small-strain elastic stiffness of the medium, as opposed to the large-strain failure or strength properties as observed by CPT, and the physics of the relation between the two is not straight-forward. However on field data, we have clearly observed that there exists such a relation (Ghose et al., 1996; Ghose and Goudswaard, 2001). The proposed reserach will involve multi-angle multi-scale analysis of seismic reflection and CPT data, theory and modelling (cavity expansion approach), and field and laboratory tests. The research is aimed at defining the underlying physics of the relation between small-strain stiffness and large-strain strength of soil, and secondly based on this understanding, to develop a method to couple shear-wave reflection data to CPT to finally derive a laterally continuous geotechnical section of important soil properties, invaluable to the engineers.
Keywords: Cone Penetration Testing (CPT), Geotechnical investigation, Lateral variations, Monitoring, Seismiek, Shear wave, Site characterization, Soil, Soil stiffness, Soil strength, Subsoil properties.

Related organisations

Related people

Project leader Dr.ir. G.G. Drijkoningen

Classification

A65000 Geotechnical engineering
D14620 Engineering geology
D15100 Geochemistry, geophysics

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