Michael E. Kalinski

Effect of Vibroseis Arrays on Ground Vibrations: A Numerical Study

Vibroseis trucks are commonly used for the acquisition of seismic reflection data for petroleum exploration because they produce low levels of ground vibration. When operating in an urban setting, vibrations are typically monitored using particle velocity meters at the ground surface, and vibration measurements are quantified in terms of peak particle velocity (PPV). Distance from the Vibroseis trucks is generally used as a parameter to identify potential points of high PPV. However, numerical modeling of PPV fields surrounding multiple-truck Vibroseis arrays reveals the presence of complex zones of constructive interference where PPV can double within as little as 3 m (10 ft). Vibroseis sweep direction and duration is shown to have little effect on PPV. The results presented herein are specific to a certain set of modeling parameters, but nevertheless demonstrate that it may be necessary to perform pre-survey numerical simulation of surface vibrations to identify points relative to the Vibroseis array that are susceptible to high vibration levels, and monitor vibrations at those points.

Estimating hydrocompression potential of mine spoils from a site in eastern Kentucky using dry unit weight and moisture content

Mine spoils created by mountaintop removal coal mining are placed in valleys to create large expanses of flat land. Mine spoils consisting of crushed fragments of mudstones, siltstones or sandstones are susceptible to significant volume change when wetted. This mechanism is referred to as hydrocompression, and has been attributed to extensive settlement. Herein, hydrocompression-induced volume change in mine spoils has been correlated to dry unit weight and moisture content. Mine spoils from eastern Kentucky were reconstituted into cylindrical specimens using different compaction efforts and moisture contents. The specimens were confined and wetted to observe changes in volume. The results indicate that hydrocompression potential depends upon the initial dry unit weight and moisture content prior to wetting, and that these parameters can be used as an indicator of settlement potential. These results are site-specific, but similar behaviour would be expected at other sites that consist of similar earth materials.

Numerical Simulation of Dynamic Behavior of Geofoam Embankment

Geofoam is gaining in popularity as a lightweight alternative to soil for construction of embankments. However, its properties are significantly different from those of soil, and the dynamic behavior of the embankment is affected by the presence of geofoam. Two-dimensional numerical modeling of a simple embankment was performed to quantify the effect of geofoam on the dynamic behavior of the embankment. The dynamic responses of three embankments—one constructed entirely of soil, one constructed entirely of geofoam, and one constructed of geofoam with a soil veneer—were simulated. Regarding surface shaking, accelerations on the surface of the geofoam embankments were higher than those on the surface of the soil embankment. Regarding liquefaction, cyclic stress ratios of subgrade soils beneath the geofoam embankment were higher than those beneath the soil embankment, primarily because of the reduced effective stress caused by the use of geofoam instead of soil. Finally, factors of safety against interblock ...

Existing technologies for deterring and defeating waterside attack of dams

Protecting dams from waterside attack is a necessary provision in the current security landscape. Nevertheless, dams remain largely unprotected. Breach of a dam would result in loss of life, property loss, and disruption of water supply and electricity sources. Waterside dam security requires technologies for detecting, deterring, and defeating attacks. Herein, the results of research to evaluate existing technologies to deter and defeat water-side attacks and mitigate the effects of attacks are presented. These technologies include physical barriers, bubble curtains, and directed energy systems. These technologies can be integrated with detection technologies such as radar and video surveillance to provide comprehensive security systems. The information presented herein is part of an ongoing study with the ultimate goal of developing and implementing effective waterside security systems that protect dams while conforming to the local social and legal environment.