Solgeo -Model SOL-CH -Cross-Hole Survey Device
Cross-Hole survey consists in the direct measurements of horizontally travelling compression (P) and shear (S) seismic waves at test sites consisting primarily of soil materials. A borehole seismic source is used to generate a seismic wave train. One or more receivers are used to detect the arrival of the seismic wave train in offset borings; the distance between boreholes at the test depths is measured using a borehole deviation survey. Wave velocity is calculated from the measured distance and travel time for the respective wave train.
P WAVES
To generate P waves an automatic energy source, SOLGEO SPARKER™ is used; it can work at many different levels of power (from 100J to 350J) ensuring frequency contents from 100 Hz up to 6 kHz; it must be used in boreholes filled with water, up to 200 m depth. An hydrophone is used as receiver of P waves in a borehole filled with water.
S WAVES
SOLGEO GEOS-H™ is used to generate S waves; it has the possibility to work in boreholes up to 200 m of depth also filled of water.
The energy source substantially is composed by two parts: a central section, that contains the pneumatic clamping assembly and second part that contains the electrodynamics waves generator. The device allows to automatically produce both upwards and downwards signals/ in order to obtain an inversion of the shear waves polarization without P waves noise.
The Solgeo vertical geophone receiver, AVG (Amplified Vertical Geophone), contain vertical sensor with an electronics preamplifier. The clamping to the borehole casing is obtained with a pneumatic device allowing surveys in boreholes till to 200 m of depth.