Data have been reviewed from sites in Europe and North and South America as well as published data from South Africa. The review has concentrated on dissipation data from piezocone tests (CPTU) to compare predicted coefficient of consolidation and permeability values using published interpretation techniques with available reference values. The results of this review have shown that the theoretical solutions provide reasonable estimates of the in situ coefficient of consolidation. Results were evaluated for pore-pressure data from different locations on the piezocone, and the least scatter in results was obtained with the pore-pressure element location immediately above the cone tip. A new correlation has been proposed to estimate in situ horizontal coefficient of permeability (kh) from piezocone dissipation data. Key words : in situ, coefficient consolidation, cone penetration test, permeability.

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Downhole and cross hole shear wave velocity determinations are becoming a routine part of dynamic site evaluation studies. The in situ measurements are frequently performed in boreholes using a variety of techniques. A seismic cone system has been developed for determining both downhole and crosshole shear wave velocity. The system consists of a source and two receivers, all embodied in penetrometers. At any depth three different polarized sets of shear wave signals can be generated and are recorded by both receivers, located at different distances from the source. It has been suggested from laboratory tests in large chambers that the measured shear wave velocities can be used to evaluate the in situ stress conditions. Tests have been performed at research sites in Vancouver to evaluate the in situ stress dependence of the measured shear wave velocities. The results of this study suggest that variations in structural anisotropy are the predominant factors controlling the directional shear wave velocities, and almost mask the effect of stress-induced variations. Les mesures de vitesse des ondes transversales, le long et entre les trous, font partie intégrante de la routine des études dynamiques d'évaluation des sites. Les mesures in-situ sont trés souvent réalisées dans des trous de forages à l'aide de diverses techniques. Le système développé permet de mesurer la fois, à l'aide d'un cône sismique, les vitesses le long et entre les trous. Ce système est constitué d'une source et de deux récepteurs intégrés à des pénétromètres. Quelle que snit la profondeur, trois différents trains d'ondes polarisées peuvent être générés puis enregistrés par les deux récepteurs situés à une distance variable de la source. Les essais de laboratoire à grande échelle laissent à supposer que les vitesses mesurées permettent d'évaluer les conditions de contrainte in-situ. Des essais ont été réalisés dans des sites d'étude à Vancouver pour évaluer la relation de la vitesse des ondes transversales à la contrainte in-situ. II ressort de cette étude que cette vitesse est principalement fonction des variations de l'anisotropie structurale qui masquent de ce fait les effets dus aux variations de la contrainte in-situ.

Dissipation of excess pore pressures during piezocone testing in firm to stiff overconsolidated fine-grained soils provides data curves that cannot be interpreted using published theoretical solutions. Available solutions are based on either cavity-expansion or strain-path methods, which have been developed for soft, normally consolidated soils and do not adequately model the response in overconsolidated soils. During penetration in overconsolidated soils, large pore-pressure gradients and unloading can exist as the soil moves past the singularity at the cone tip shoulder; these gradients modify the initial pore-pressure distribution around the tip and along the friction sleeve and give rise to nonstandard dissipation curves. The different types of response resulting from the modified pore-pressure distribution are discussed and classified and a correction technique is proposed. In this way, the application of available theoretical models can be used to evaluate in situ flow characteristics. Examples of the different types of pore-pressure response are presented from various sites worldwide.Key words: cone penetration test, in situ, clay, overconsolidation ratio, pore pressure, dissipation, consolidation.

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