Free-fall penetrometers (FFPs) are an attractive tool for the rapid characterization of sediments in the nearshore and coastal areas. To improve their measurement capabilities, modern FFPs can be equipped with pore pressure sensors. Pore pressure measurements are extensively used in traditional cone penetration testing, but their usage and interpretation is still limited for FFP testing. This thesis represents an effort to advance the interpretation of pore pressure measurements from FFP testing. Data was collected using the torpedo-shaped FFP BlueDrop during surveys at Herschel Island, YT, Yakutat, AK, Clay Bank, VA, and Yorktown, VA. Additionally, test deployments in the laboratory were performed in kaolin clay. Data analysis was focused on pore pressure measurements during these deployments. Two major advancements regarding current data analysis of FFP pore pressure measurements were explored: 1) a method based on fluid dynamic principles was proposed to correct the pressure recordings for the dynamic flow effects due to the high-velocity fall and impact. The results show that using Bernoulli’s theorem coupled with the concept of pressure coefficients results in good agreement between measured and hydrostatic pressures during the free-fall and initial penetration stage. 2) Pore pressure dissipation curves measured by the penetrometer at rest at maximum penetration depth were also studied. The mechanisms behind the non-standard dissipation curves were explored. The results suggest that non-standard dissipation curves can be interpreted by correcting according to Sully et al.’s (1999) extrapolation technique. The technique can also be used with data from an unsaturated or clogged filter. / Master of Science / An increasing use of nearshore and offshore areas for the development of infrastructure such as pipelines, cables, renewable energy harvesting devices, and measures against coastal erosion warrants the development of specialized methods for investigating the stability of the seabed. Portable free-fall penetrometers represent a cost-efficient approach to characterize shallow seabed sediments, but there are challenges associated with deriving geotechnical design parameters from these novel instruments. This study aims at developing a better understanding of the pore pressure (the pressure developed in the water in the soil’s voids) data obtained during free-fall penetration testing. The pore pressures developed during the penetration of the penetrometer is dependent on the soil type, and is often used to correlate to it. This study used data obtained from field surveys at Herschel Island, YT, Clay Bank, VA, Yakutat, AK, and Yorktown, VA. Additionally, controlled tests were performed in the laboratory in an instrumented seabed. This study resulted in a novel method to correct the pressure data from the penetrometer for dynamic fluid flow effects and validation of an interpretation technique for dissipation curves to obtain the time required for consolidation, based on initial results.

In underground construction and foundation engineering uncertainties associated with subsurface properties are inevitable to deal with. Site investigations are expensive to perform, but a limited understanding of the subsurface may result in major problems; which often lead to an unexpected increase in the overall cost of the construction project. This study aims to optimize the pre-investigation program to get as much correct information out from a limited input of resources, thus making it as cost effective as possible. To optimize site investigation using soil-rock sounding three different sampling techniques, a varying number of sample points and two different interpolation methods (Inverse distance weighting and point Kriging) were tested on four modeled reference surfaces. The accuracy of rock surface predictions was evaluated using a 3D gridding and modeling computer software (Surfer 8.02®). Samples with continuously distributed data, resembling profile lines from geophysical surveys were used to evaluate how this could improve the accuracy of the prediction compared to adding additional sampling points. The study explains the correlation between the number of sampling points and the accuracy of the prediction obtained using different interpolators. Most importantly it shows how continuous data significantly improves the accuracy of the rock surface predictions and therefore concludes that geophysical measurement should be used combined with traditional soil rock sounding to optimize the pre-investigation program.

Yes / In the discussions that have taken place over the past six years since the establishment by the Third Review Conference1 in 1991 of the Ad Hoc Group of Governmental Experts,known as VEREX, to identify and examine potential verification measures from a scientific and technical viewpoint, there has been an increasing debate about the role of non-challenge visits in a regime for a strengthened Biological and Toxin Weapons Convention (BTWC). The arguments as to why on-site investigations are an essential and central element to such a strengthened regime were addressed in the Briefing Paper issued2 in July 1997. In this Briefing Paper, the necessity for non-challenge visits is addressed drawing upon the previous VEREX, Ad Hoc Group (AHG), Chemical Weapons Convention (CWC) and United Nations Special Commission (UNSCOM) experience. The advantages and disadvantages of a regime containing non-challenge visits are considered and the conclusion is reached that the advantages far outweigh the disadvantages and that non-challenge visits are an important element which could contribute significantly to the effectiveness of a future legally binding instrument to strengthen the BTWC.

Deep excavations have been used worldwide for underground construction, but they also alter the ground conditions and induce ground movements which might cause risks to adjacent infrastructure. Field measurements are normally carried out during excavations to ensure their safety, and also provide valuable data to calibrate the results from the numerical analysis which is an effective way to investigate the performance of deep excavations. This thesis is concerned with evaluating the capability of advanced finite element analysis in reproducing various aspects of observed deep excavation behaviour in the field through back analysis of case histories. The finite element model developed considers both geotechnical and structural aspects such as (i) detailed geometry of the excavation and retaining structures, (ii) realistic material models for the soil, structures and the soil-structure interface, and (iii) correct construction sequences. Parametric studies are conducted first based on a simplified square excavation to understand the effect of several important aspects, e.g. (i) the merit of shell or solid elements to model the retaining wall, (ii) the effect of construction joints in the retaining wall, (iii) the effect of the operational stiffness of concrete structural components due to cracks, (iv) the thermal effect of concrete beams and floor slabs during curing process and due to variation of ambient temperature, (v) the effect of soil-structure interface behaviour, and (vi) the effect of stiffness and strength properties of the soil. Two more complex case histories are then investigated through fully 3D analyses to explore the influence of various factors such as (i) neglecting the small-strain stiffness nonlinearity in the soil model, (ii) the selected K_0 value to represent the initial stress state in the ground, (iii) the appropriate anisotropic wall properties to consider the joints in the diaphragm wall, (iv) the parameters governing the settlements of adjacent buildings and buried pipelines, (v) the effectiveness of ground improvement on reducing the building settlement, (vi) the variation of construction sequences, (vii) the effectiveness of earth berms, and (viii) ignoring the openings in the floor slabs. This research has strong practical implications, but cautions should also be taken in applications, e.g. element types and parameter selection.

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / Arizona's continued growth and development depends upon sound management of water resources, especially melted snow which is the primary source of water for the 1.1. Million residents of Maricopa county. The method for snowpack information gathering practiced by watershed specialists of the Salt River project in Arizona is described. The method is outlined, describing aircraft reconnaissance, direct enroute mapping of extent and depth of snowpack, and techniques for identifying ice and/or melt conditions. Under optimal conditions, this technique is considered more than acceptable for determining snowpack levels. Limitations of the technique result from the observer's tolerance of vertigo which can arise under flying conditions; cloud cover, which can reduce contrast and shadows thereby reducing accuracy of observation; and vegetation zones where density of plant matter screens much of the snow.

From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / As a part of the ongoing Phoenix Urban Study, Federal legislation mandates that land treatment of wastewater be seriously considered as a treatment option. Land treatment is a particularly viable alternative in the Phoenix area because in this arid desert climate, all water is a scarce and valuable resource and land treatment offers a positive opportunity for the conservation of this resource. In addition, land treatment systems are generally less expensive and have lower energy requirements than other conventional treatment processes while resulting in comparable treatment. The analysis of wastewater treatment systems for populated urban areas necessitates the preliminary investigation and comparison of a large number of alternatives to allow for a realistic engineering and economic evaluation. The site specific nature of land application adds additional variables that must be considered. A preliminary systems approach indicated that to minimize the effect of a human judgement factor between sites and yet maximize the depth of the initial analysis, computer techniques should be utilized for analysis and data storage. A summary of this analysis with appropriate cost, power usage, land requirements and other pertinent factors will be presented.