The recent development and deployment of HYACINTH and IODP PCS pressure cores on the JOIDES Resolution during Expedition 1 of the Indian National Gas Hydrate Program (NGHP-1) has provided some of the first “undisturbed” samples of gas hydrate in fine grained marine sediments. Some samples, once recovered from the seafloor, were subject to rapid depressurization and subsequent immersion in liquid nitrogen, at approximately -196oC, for use in subsequent laboratory test programs. This paper describes the techniques used at Southampton University, the difficulties encountered, and the results obtained from geotechnical testing of these samples. The original intention had been to pressurize and unfreeze the material before testing it in the Gas Hydrate Resonant Column (GHRC) Apparatus. Initial CT scanning of the samples showed that the sample quality might be too poor for such testing, and this proved to be the case. Instead a suite of geotechnical testing was carried out, the results of which are reported and interpreted in this paper.

Abstract This thesis has shown that the development of the instrumentation necessary to provide in-situ thermal imaging for the determination of homogeneity of concrete is theoretically sound. Drilled shafts are large diameter underground cast-in-place columns that necessarily rely on sound integrity to properly withstand imposed loadings. As a by-product of the most common construction techniques, the entire process is often completely blind whereby the excavation and concreting processes are conducted beneath the surface of the water table (or slurry level). This results in an inability to inspect the final product and in many cases allows anomalous inclusions (soil cave-ins, slurry pockets, etc) to go undetected especially when they are formed outside the steel reinforcing cage. In an effort to gain verification of the as-built, below ground structure, numerous non-destructive test methods have been devised. Each of these methods have merits and drawbacks with regards to the full extent of the tested concrete volume. To further this cause, a new methodology was developed that uses the energy from hydrating concrete to assess the presence or absence of an intact concrete. Therein, the temperature generated by the curing concrete can be measured and correlated to the probable dimensions of the drilled shaft. This thesis outlines the development of the instrumentation capable of making in-situ temperature measurement of drilled shafts to assure the homogeneity of concrete is acceptable. To that end, several configurations of instrumentation approach were tested on varying scales from small lab specimens to full-size field constructed drilled shafts. The bulk of this work was conducted several years before the completion of the thesis and has the benefit of noting later developments. For instance, this study was used to seed future research and led to subsequent FDOT and WSDOT (Washington State DOT) funded research for the express purpose of identifying capabilities of thermal testing in those states. Likewise, present day practice and use of the approach has also been documented.