Analysis of Video Images obtained during Cone Penetration Testing

Abstract

One of the ways to enhance the efficiency of the cone penetration testing process is to mount modules behind the cone. In this way the test will not only generate the standard Cone Penetration Testing (CPT) data (i.e., cone tip resistance, sleeve friction, and dynamic pore water pressure), but also the data obtained by the module pushed into the soil together with the cone. While for certain modules it is common practice to analyze the acquired data extensively (e.g., the seismic module) for other modules this is not necessarily the case. A good example of the latter is the video module, which has been available for several decades. When this module is deployed with visible light, the analysis is typically limited to viewing the recording and adding observation notes. During the recent TRIM4 research project the video module was deployed and subsequently attempts were made to identify the soil type through an automatic analysis of the video images and to characterize and to determine the grain size distribution using the video images. This approach is highly correlated with the soil behavior type index, commonly used in the analysis of CPT data, and at the same time mitigates the effect of the CPT data reflecting changes in soil strength behavior before a layer is actually penetrated by the cone. In this paper the authors will describe the use of the video cone in very general terms, but focus on this analysis methodology in detail

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