The results from the use of the dilatometer (Marchetti 1975, 1980) at 4 sites in British Columbia are presented. Comparisons are drawn between the dilatometer and other insitu test devices, including the piezo-friction cone, self-boring and Menard pressuremeters and field vane. Soils tested included saturated deltaic deposits, a sensitive plastic clay and a saturated, hydraulically placed fill. Overall the dilatometer proved to be an extremely effective device. It had a low capital cost, required a minimum of support equipment and was simple to use. The data was repeatable and easily reduced using a computer programme. Computer output, both graphical and tabular, is easily amenable to interpretation to an engineer in the field. For the most part the results in this thesis support Marchetti's empirical correlations with the following exceptions: ( i) determination of K0 in sands, ( ii) determination of a deformation modulus in clay, and (iii) in overconsolidated silts where it is believed that abnormal pore pressures caused the empirical correlations to breakdown. The dilatometer is an insitu, total stress, penetration device which cannot be analysed in a fundamental manner. Elastic theory is inapplicable because of plastic straining during blade penetration and probably during membrane expansion. To more critically evaluate the dilatometer, the author designed an electronic research device with exactly the same external dimensions as Marchetti's dilatometer. The aim of the electronic dilatometer is to greatly improve understanding of the simple Marchetti dilatometer by allowing: ( i) a better understanding of the operational characteristics of Marchetti's dilatometer, ( ii) direct measurement of stress on, and deformation of, the membrane, (iii) measurement of pore water pressure before and after halting penetration and during membrane expansion, and ( iv) measurement of the pushing force on the blade. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Thesis (M. Phil.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 102-106).

published_or_final_version / Civil and Structural Engineering / Master / Master of Philosophy

No description available.

No description available.

Thesis (Ph. D.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 89-98).

No description available.

The flat dilatometer (DMT) and piezocone penetration (CPTU) tests are likely to be among the most widely used in situ testing methods for soil characterization and indirect determination of geotechnical design parameters such as: strength, stiffness, permeability and compressibility. The flat dilatometer has proved to be a reliable, robust and adaptable tool, and the data obtained with this instrument is very repeatable, and easy to reduce and process. Furthermore, the addition of a seismic module to the standard flat dilatometer (SDMT) to measure the shear wave velocity (Vs) significantly complements the set of data typically obtained with a standard DMT test. Nonetheless, the experience in interpreting the combination between Vs and DMT data is fairly limited due to the recent introduction of the SDMT for commercial applications. Additionally, the estimation of the coefficient of earth pressure at rest (K₀) has been the most important application of the DMT since its introduction. However, a potential weakness of the DMT is that the derivation of K₀ is based upon empirical correlations developed some time ago and neither improvement work nor upgrade of these approaches has been performed in the last 10 years. Throughout the years several additional sensors have been developed in order to supplement the data collected with the CPTU test. Among the wide variety of sensor developed, the lateral stress module mounted behind a piezocone represents a promising tool for estimation of in situ lateral stress conditions from the interpretation of lateral stress penetration data. However, the popularity of the so called lateral stress cone has declined over the years due to constraints in both the instrumentation and the interpretation of measured data. Also, the application of this instrument remains limited to specific soils conditions and specific projects. However, the valuable experience gained throughout the years in the development and application of several lateral stress cones in combination with developments in electronics and understanding of soil behaviour allow the improvement of this type of technology. This thesis presents the results of a comprehensive laboratory and field testing programs performed by the author at several research sites located in the Lower Mainland of BC, undertaken in order to assess the performance of the seismic flat dilatometer and lateral stress seismic piezocone (LSSCPTU), built and develop at UBC. Firstly, the analysis of field measurements with the SDMT collected at several sites have demonstrated the potential for an improved soil characterization through the combination of DMT parameters and the small strain shear modulus (G₀). Additionally the usefulness of the DMT-C closing pressure for soil identification is shown. On the basis of several relationships identified from this data, a new soil type behaviour system based upon SDMT measurements is proposed. Furthermore, empirical correlations based upon fairly large and updated databases have been developed to estimate K₀ and Vs values from DMT parameters.

A new mineralogical approach is introduced to predict aggregate and concrete coefficient of thermal expansion (CoTE). Basically, a modeling approach is suggested based on the assumption that the CoTE of aggregate and concrete can be predicted from the CoTE of their constituent components. Volume percentage, CoTE and elastic modulus of each constituent mineral phase are considered as input for the aggregate CoTE model, whereas the same properties for coarse aggregate and mortar are considered for the concrete CoTE model. Methods have been formulated to calculate the mineral volume percentage from bulk chemical analysis for different type of rocks commonly used as aggregates in Texas. The dilatometer testing method has been established to measure the CoTE of aggregate, pure minerals, and concrete. Calculated aggregate CoTE, based on the determined CoTE of pure minerals and their respective calculated volume percentages, shows a good resemblance with the measured aggregate CoTE by dilatometer. Similarly, predicted concrete CoTE, based on the calculated CoTE of aggregate and mortar and their respective volume percentages compares well with the measured concrete CoTE by dilatometer. Such a favorable comparison between predicted and measured CoTE provided a basis to establish the composite model to predict aggregate and concrete CoTE. Composite modeling will be useful to serve as a check of aggregate source variability in terms of quality control measures and improved design and quality control measures of concrete.

published_or_final_version / abstract / toc / Civil Engineering / Doctoral / Doctor of Philosophy