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UDC 628.241

Lobanov A. A., Gromov A. A., Zhuravlev A. E.

The experience of constructing the extension of the main sewer  in the northern part of St. Petersburg

Summary

The experience of constructing the extension of the main sewer in the northern part of Saint-Petersburg is presented. The works were carried out in a complex hydrological environment with the use of advanced tunneling machinery. Pressure-gravity drain siphon was chosen from the options considered. During the shaft construction both traditional methods (drilling freezing columns, shaft free­zing with formation of glacial soil massive, boring in glacial soil shield with installation of immediate support of reinforced concrete tubing, construction of reinforced concrete jacket and technological shaft equipping), and new ones (shaft shielding with piled walls followed by drilling and constructing reinforced concrete jacket, shaft boring with shaft sinking machine and installing immediate support of segment blocks and sinking the whole support structure with shaft sinking) were used. In the process of constructing the main siphon tunnels boring with mechanized complexes with simultaneous assembling the immediate support of the tunnel with reinforced concrete tubing was used. At wash-out site in the process of boring the second line of the siphon an advanced tunnel-boring complex with hydroweight and hydrohaulage with constructing immediate support of the tunnel of segment blocks was used. To provide for the nonsilting flow rate in the sewer under the conditions of wastewater flow decrease a flow regulation facility was built in the lowest sewer point. The use of the advanced tunneling complex provided for shortening the timeline to completion of the sewer construction, ensu­ring leaktightness of the constructions and operations safety eliminating workers access to the tunnel face. Commissioning the extension of the sewer in the northern part of Saint-Petersburg provided for increasing wastewater treatment to 98.4%.

Key words

wastewater , monitoring , sewer , gas corrosion , shaft , tunneling complex , microtunnel