This presentation is intended to provide background on the principles involved in geotechnical and infrastructure applications of Time Domain Reflectometry (TDR). TDR is basically radar in which a voltage pulse is launched along a coaxial cable. A reflection of the voltage pulse occurs at every location where the cable is...
Time Domain Reflectometry (TDR) is a versatile technology amenable to a variety of measurements and nondestructive monitoring of infrastructure conditions. It can be utilized to monitor deformation of soil/rock and structures, monitor changes in fluid levels, and monitor water content of soils. Furthermore, this monitoring can be automated using systems...
Two longwall coalmine panels were mined at a depth of approximately 156 m (510 ft) beneath I-70 east of Washington, Pennsylvania such that it crossed the width of one panel at two locations. The Pennsylvania Department of Transportation (PennDoT) assumed responsibility for real time monitoring of both ground deformation and...
This paper describes qualification of devices to measure sub micro-meter changes in crack width, which is the basis of autonomous crack monitoring for control of blasting vibrations. Performance of LVDT, eddy current and potentiometer sensors to monitor long-term and transient displacements will be described. Potentiometers are attractive for wireless measurement,...
Mining near the town of Blanford, Indiana for a number of years has led to an opportunity for Peabody Coal Company to study and compare environmental and blast effects. Such a comparison allows description of any blast effects relative to those caused by common environmental changes, which should be familiar...
Construction is omnipresent in modern-day America. It's the sound and vibration of a nation scrambling to keep up with its burgeoning population. In most states, allowable construction-induced ground motions range from 0.5 to 1.0 inches per second (in/sec) and under certain
conditions up to 2.0 in/sec.
However, ground motion as...
This appendix synthesizes micrometer changes in crack width in response to both long term (environmental) and transient (blast vibration) of four of the structures in the main body. The appendix begins with a description of the genesis of the study and instruments employed. Response of the distressed wood-framed structure in...
In this paper vibratory crack response is compared to that produced by volumetric changes in foundation soils induced by natural events. These natural phenomena include changes in the water table, changes in soil moisture, and formation of ice lenses to name a few. Previous papers have compared vibratory responses of...
Cosmetic and structural cracks are a large concern for homeowners. Although these cracks can develop from a variety of causes: differential foundation settlement, occupant activity, climatological effects, as well as dynamic events, people tend to look to dynamic events like blasting, construction, or traffic vibrations to be the culprit. This...
The notion of blasting, even in a controlled setting such as a limestone quarry, can be alarming to residents and business owners within earshot. Because humans are inherently sensitive to blast-induced vibrations, they perceive that the structures in which they live in are equally sensitive. The goal of this project...