DETERMINATION OF MORAINE AND BEDROCK ROOF DEPTH

Shallow engineering seismic survey by reflected waves

The problem of determining the surface of bedrocks or dense moraine soils depth arises in assessing the penetration of foundation piles, determining the lower boundary of sandy or gravel soils in assessing the reserves of construction materials in quarries.
The roof of dense moraine soils or bedrocks is usually manifested in seismic sections of reflected waves as a clear, well-correlated reflecting horizon.
Seismic profiling is performed by the method of multiple overlaps with the accumulation of signals reflected from the common depth point on the boundary (CDP).

GPR low-frequency sounding

The structure of the array of loose soils, the configuration of the reflecting boundaries in their thickness, the form of contact with the underlying moraine loams or bedrocks are most detailed displayed on the sections of GPR sounding. The depth of research on dry sandy soils with low-frequency dipole antennas can reach 10-15 m.
In combination with the shallow-depth seismic survey by reflected waves, it is possible to significantly increase the depth of studies of the soil massif and rocks.

Seismic profiling by the method of refracted waves

One of the simplest and cheapest methods to study the structure of the bedrock surface is method of shallow-depth seismic exploration by refracted waves. The method usually does not allow to trace weak boundaries of the section in the thickness of loose soils, but gives a clear idea on the depth and configuration of a strong refractive boundary associated with the surface of the bedrocks.
In addition, the method provides information about the lateral variability of physical properties of both the loose soil layer and the weathered surface layer of the bedrock.