Ground-Penetrating Radar in many environmental and civil engineering projects. In its basic form, Ground-Penetrating Radar equipment consists of a portable antenna and control unit. The Antenna is pulled along the ground surface over an area of interest and radar is transmitted into and reflected out of the ground based upon the conductivity of the subsurface materials encountered.
Several different antennas can be utilized depending upon the application and required depth of penetration. In typical Long Island sand, a 400 megahertz antenna can penetrate to depths ranging from 1 foot to 10 feet – the range most underground storage tanks and utilities are found within. A 300 megahertz antenna can penetrate depths of 15 feet or more and is suitable for surveying zones where debris piles, landfills or bedrock surfaces may be located. A small 1,000 megahertz antenna can locate re-bar or utility voids in concrete floors.
ACT employees have been trained and certified to use Geophysical Survey Systems, Inc. (GSSI) equipment. ACT is one of the few consulting firms in the NYC Area who are certified to perform GPR.
Uses of Ground-Penetrating Radar and Utility Surveys
A Ground-Penetrating Radar survey can be utilized as a stand alone investigation or preliminary to a Phase II Environmental Site Assessment. In environmental applications, Ground-Penetrating Radar can verify the presence of suspected buried structures and delineate the boundaries of known underground storage tanks and drainage structures (ie. leachpools, cesspools or drywells).
Previously excavated and backfilled areas such as former tank pits, landfills or other waste disposal locations can also be readily identified. In civil engineering applications, Ground-Penetrating Radar can identify the density of materials at various depths and locate the presence of voids beneath buildings or road surfaces. Ground-Penetrating Radar has even been used in archeological investigations to locate ancient Indian burial grounds.