Method of surveying and determining thicknesses and properties of subsurface ground layers without excavation

摘要

A non-excavating method for surveying individual subsurface layer thicknesses and properties of a ground, such as a road or other sites, by obtaining propagation velocities of vibration energy of predetermined frequencies which propagates through the subsurface layers ranging from the top surface to at least a subgrade section. The thicknesses of individual subsurface layers covering the depths from the ground surface to the subgrade are determined from the differences of the propagation velocities of the vibration energy and identifying each of the propagation velocities with the average propagation velocitiy of the corresponding wave propagated through the subsurface ground having the depth equal to one half of the corresponding wavelength. The properties of the individual subsurface layers are also determined by utilizing the correlation between property values, such as bearing strength ratios, of the constituent materials of the layers and the propagation velocities of the vibration energy.