Liquefaction potential and piezocone response

Roger Anton Vreugdenhil ,R O Davis,J B Berrill

doi:10.5459/bnzsee.28.2.106-112

Roger Anton Vreugdenhil , R O Davis + Show 1 more

Open Access

https://doi.org/10.5459/bnzsee.28.2.106-112

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Abstract

    A simple approximate analysis is presented for interpretation of cone penetration results when the cone resistance is affected by layering of soils with different stiffnesses. It is argued that the cone resistance senses the presence of a nearby layer elastically, and an approximate elastic analysis is developed to quantify the effect. Good comparisons with calibration chamber experimental results are found. This has important implications for soil classification and for assessment of liquefaction potential from cone penetration results.   

Highlights

Often when comparisons are drawn between cone penetration tests (CPT) and standard penetration tests (SPT), an advantage is attributed to the CPT due to the continuous nature of the test results
In this paper a simple elastic analysis has been presented to explain how cone penetration resistance may be affected by the presence of nearby soil layers with different stiffness characteristics
It is suggested that the perceived penetration resistance may "sense" nearby layers

Summary

INTRODUCTION

Often when comparisons are drawn between cone penetration tests (CPT) and standard penetration tests (SPT), an advantage is attributed to the CPT due to the continuous nature of the test results. The CPT itself may not precisely define thin soil layers, even though a continuous measure of penetration resistance is obtained. As the cone approaches a stiffer layer for example, it will "sense" the presence of this layer some distance before actual penetration of the stiffer soil occurs. After the cone enters the stiffer layer, its response will continue to sense the softer soil above, and this will result in a lower resistance for some distance in the stiffer layer. These effects have been well documented in calibration chamber experiments (Canou [1], Foray and Pautre [2)). The penetration resistance may be greatly different from the value obtained in a homogeneous deposit of the same soil

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CONCLUSIONS