The Crimean Bridge. Improvement of the base soil at the approaches to the bridge.
The material is taken from the Construction Weekly Magazine, written by Bogdanov I. Chief Structural Engineer.
Construction sites like the Crimean Bridge are single, unique, and usually represent a complex of structures of different complexity.
At the design of bridge crossings (both road and rail), one of the problems for engineering companies was the instability of the soil in the bridge/shore zone (the base of the soil embankment). High seismicity of the area, waterlogging of the base soil, damage of the original soil structure during the extraction of salt, and medicinal clays on the Tuzla spit indicated the need to improve and drain these soils.
As a result of the assessment of technologies on the world market that are used to solve this type of problem, a new technology for the Russian market was chosen that is improving the Foundation on approaches to bridge by crushed stone piles, offered and implemented by GEOIZOL. It is based on the principle of simultaneous replacement and compaction of the existing foundation soil by adding inert construction materials, specifically crushed stone, to the drilled well, creating a column with a diameter of 1000 mm. This column (crushed stone pile) is a drain of excess water in the base and for soil consolidation. It also provides stability of the structure and compaction of the host soil (sand, compacted clays).
When making a crushed stone column, all product characteristics are recorded by the onboard equipment: the degree of compaction of crushed stone, the depth and diameter of the well at all intervals, the production time, the volume of inert materials used. This allows to constantly monitor the quality of work performed and compliance to design solution. Control of compaction of the host soil is performed by cone penetration tests before and after work.
Our work was estimated by many parameters, the main ones were time, quality, and cost. These criteria specifically are why modern technical solutions win over old ones. And such large-scale construction projects allow new solutions to be implemented, they just move these solutions forward. The Crimean Bridge also allowed applying new solutions that will later be implemented at other construction sites in Russia.