There have been several recent reports of collapsed roads at the various locations throughout the Bangkok metropolitan area. Most of the problems are caused by improper construction of utility networks and poor rehabilitation work. Ground penetrating radar GPR technique was selected to investigate the potential presence of subsurface voids under the road surface. In geotechnical and structural applications, GPR is an excellent tool for being able to image steel reinforcing bars, voids and tendon ducts in concrete structures and, more relevantly to this study, voids beneath concrete roads. The objective of this study was to survey the area for potential voids that might exist under the road surface using ground penetrating radar technique. The GPR survey campaign was divided into two stages, which were the preliminary and detailed surveys.
What do holes and voids mean?
Void detection using GPR
Our non-intrusive GPR void detection surveys can detect voids beneath slabs. By scanning on a regular orthogonal grid, the void location and extent can be determined and plotted. Voiding can occur for a number of reasons. Natural voiding can be caused by settlement, washout e. Voids can also be man-made, examples being basements, culverts, underground tanks, tunnels, pipes, etc. Voiding in the sub-surface can cause failures of the overlying strata, particularly if the area is subjected to abnormally heavy loads. The collapse of a void under a carriageway is likely to cause structural damage and can result in accidents. Voids beneath a warehouse slab or loading bay can result in slab deterioration and ultimately a failure, particularly if trafficked by fork-lifts or lorries. The detection and location of voids are therefore highly desirable and enables repairs to be undertaken before structural problems occur, improving safety and saving money.
GeoModel, Inc. Professional Geologist will also observe geologic features in the area that may be related to any sinkhole activity or underground voids. To further investigate a sinkhole location or void location study, the GeoModel, Inc.
No matter what the problem is, GPR is great for sinkhole and void detection. What are the differences between sinkholes and voids? Sinkholes, while appearing to pop up suddenly and cause major damage, develop over a period of years as a result of many different processes. Sinkholes are caused by Karst processes. Karst processes happen when bedrock in the land is soluble. Soluble bedrock is typically made from limestone, dolomite, other carbonate rocks, gypsum, anhydrite, or other evaporitic rocks. Sinkholes can be incredibly tiny or incredibly massive in size.