Detection and characterization of subsurface cavities,tunnels and abandoned mines

摘要

Despite decades of effort,detection and characterization of subsurface cavities,runnels and abandoned mines remains one of the most difficult classes of problems addressed by near-surface geophysics.As geophysical technology has advanced,so have the difficulties of the requirements.Three primary application areas are drivers for development of geophysical technology for cavity and tunnel detection: geotechnical and safety considerations;civilian criminal activities;military considerations.Natural cavities and abandoned mines are safety threats to man and his expanding utilization of land and natural resources,and pose significant design and construction problems for new engineered structures.Tunneling and utilization of existing cavities and mines have long been used for criminal activities such as smuggling,prison escape,robbery,and caches.With discovery of tunnels under international borders,used for human trafficking and contraband smuggling,new and challenging requirements for geophysical detection technology have emerged.In a military context,tunneling and utilization of existing cavities and tunnels have played important roles throughout history for logistics and storage,troop insertions behind enemy lines and across borders,intelligence operations,terrorism,accessing secure installations,and deeply buried facilities.The basic physics of detection haven't changed,and no dramatic technology breakthrough has occurred.However,significant advances in geophysical data acquisition,processing and interpretation capability have dramatically enhanced possibilities for cavity detection and characterization.Following a historical perspective and review of basic concepts,brief case histories illustrate approaches,continuing challenges,and rules of thumb for cavity,tunnel,and abandoned mine detection.