Academic literature on the topic 'MATERN 5/2 GPR'

A geophysical survey was carried out in 2012 to map the subsurface geology at a quarry and the village to determine if an alleged damage to houses could have been caused by blasting activity in the quarry. The survey included seismic refraction and reflection recorded with the same spread at source and receiver spacing of 2 m, 3 m, and 5 m. The signal source was a 28-lb. sledge hammer stacked 10 times to increase the S/N. Ground penetrating radar (GPR) was also recorded at a trace spacing of 0.3 m to provide detailed images of the subsurface near the damaged buildings using a 50 MHz unshielded antenna. The seismic refraction and reflection profiles show that the village is underlain by 0-4 m of loose sand, 4-10 m of fractured calcrete, and up to 50 m of fractured silcrete, with the groundwater table at 10-15 m. The GPR images show that the damaged houses sit on thick sand, which cushions them against severe ground vibration. The houses were found to have suffered more damage on the superstructure and this is possibly due to ground vibration amplification at low frequencies of 30-40 Hz.

Subways and other rapid transit systems are marked symbols of the modern metropolis. As a transdisciplinary service, accurately and safely positioning and tracking the metro trains helps the passengers to plan their travels and provides the operators with auxiliary information about the trains to enhance the metro system’s resilience. However, many general-purpose positioning technologies, such as Global Navigation Satellite Systems (GNSS) and Wi-Fi signals, do not apply to the situations of underground metro trains. In this paper, we propose a two-stage framework for automatic real-time tracking of metro cars implemented only with low-cost accelerometers, saving the expense for complicated infrastructures. In the off-line stage, reference maps are developed for station-to-station track sections using the onboard acceleration data. To handle the missing data and uncalibrated consumer-grade sensors, Gaussian process regression (GPR) is adopted to denoise and interpolate the online acceleration readings, followed by the application of the Kalman filter algorithm to track the cars in real-time with the help of the reference map. We tested the proposed system in Wuhan Metro Line 2, and the results showed that our system achieved an error below 5% in positioning.

Resilient modulus (MR) is a key factor in the Mechanistic Empirical Pavement Design Guide (MEPDG) which was adopted by INDOT in January 2009. The resilient modulus can be determined in new pavement projects from subgrade soil samples collected at the site. However, for a pavement rehabilitation project, it becomes difficult to obtain soil information, and coring for samples may not be feasible because of traffic. The literature is rich with correlations between the MR of the subgrade obtained in the laboratory with that estimated from FWD tests in the field. However, the review conducted shows