The technology of investigation of soil-cement fences by acoustic raying is intended for control of the integrity of soil-cement fences made by the method of jet cementation, before driving and construction.

The main diagnostic characteristic of the integrity of soil-cement fences is the speed of longitudinal elastic waves in soil-cement. In 2001–2006 in St Petersburg, integrity monitoring of soil-cement fences was executed at shafts 4 (Grazhdansky prospekt) and 1 (Kushelevka) of the relief sewer in the Ploshchad Muzhestva area, the ring road tunnel at the junction of Toksovskaya street (Murino), cells of sections 1 and 2 of the construction of the second stage of the Mariinsky Theatre, the tunnel part of the T-4C complex of the St Petersburg protective structures against inundations, and others. On the basis of data from acoustic raying of shaft 4 (Grazhdansky prospekt), a decision was made to conduct additional injection, which provided closing of the zone of discontinuity flow and, finally, accident-free shaft sinking.

Soil-cement piles of road foundations

The technology of investigation of soil-cement piles of road foundations by acoustic raying and logging is intended for monitoring of bearing properties: soil-concrete integrity, length, diameter and strength. The essence of the method is excitement of an impulse of acoustic waves, which passes through the soil-concrete, and assessment of the bearing state by comparing the acoustic wave impulse with the table of diagnostic properties of bearing states. Soil-concrete strength monitoring is executed on the basis of the dependence between acoustic waves and strength in linear compression. In 2004–2006 the technology was widely used in the construction of the ring road around St Petersburg, in sections LOT1 and LOT6.