Piles Installed With an 18-Degree Inclination

Dismantling the conductor guide

In the Rostov Region, Stroytransgaz Group builds the Bagaevsky Hydroelectric Complex, an important facility for the entire country. This project will ensure safe navigation on the Lower Don, a part of the navigation system of the single deep-water system in Russia.

A lock, upper and lower approach channels with berthing guide structures, spillway and earth dams, a fish bypass and spawning channel, a settlement for operators and other facilities will be built as part of the Hydroelectric Complex.

Piles installed with an 18-degree inclination 

Today we will talk about mooring and approach channels and their layout. The dimensions and outlines of the two-way approach channels shall ensure safe separation of ships entering and leaving the lock and safe parking conditions for those awaiting the lock. The approach walls represented by walls rounded at the edges (radial part) of mooring and approach channels are built for smooth entrance of vessels into the lock chamber.

The mooring and approach channels of the shipping lock are special vertical structures in the form of double walls with anchors on both sides of the channel. Today, the front wall made of Larssen sheet piles (5-UM) is installed.

Driving of the anchor pile (used to protect the conductor guide from axial displacement)

Andrey Vinokhodov, HM and Auxiliary System Installation Section Manager, spoke about special aspects of Larssen sheet piling, "When a Larssen sheet pile is driven, a fanning is formed, i.e. the sheet piling is stretched under the weight of the plunger and becomes wider at the top than at the bottom. It is especially evident when diving into hard rock. The deviation is usually small, about 1mm per total length of the pile. But after a certain number of sheet piles is driven, a fanning is formed. To level and drive them vertically again, a wedge pile is made. Its top is narrower than the bottom. We make it ourselves at the facility, prepare all required documents and perform welding quality control procedures. Only after that it is delivered to the construction site."

To date, we have approached the radial part of the Larssen sheet piling on the right wall. To align the horizontal part when turning, a wedge pile will be used. And to drive the radial part of the Larssen sheet pile itself, the builders and surveyors developed a two-level radial conductor guide.

The same conductor guide was used when driving the radial part of the left wall. The installation of anchor plates has now commenced there. The conductor guide was modified for 20 m long inclined piles with the diameter of 720 mm. The pile is driven at an inclination of 18 degrees to the design mark of minus 18.5 meters.

"Since the anchor rods are crossed, i.e. they are installed on two levels, one at the elevation of +300 and another at the elevation of +2,000, the piles are driven at an inclination. When driven strictly vertically, the piles will not perform their functions," explained Andrey Vinokhodov.

Today, anchor plates are also being installed as a kind of anchor for the channel walls. The anchor wall is installed at two stages. At the first stage, the soil is sampled up to the zero mark of the Baltic elevation system, then the gravel bed is poured and compacted, the formwork is installed and the concrete blinding is poured. Dam concrete B7.5 is used. The next step is to concrete the vertical anchor wall, which will also be cast with special dam concrete B25F150W6. The anchor wall serves as an anchor for the front sheet pile wall. The next stage is the installation of anchor rods, the connecting element of the two walls of the approach wall.

*Larssen sheet pile is a metal shape representing a groove with rounded edges of side walls or with locks.

Project background:
The Bagayevsky Hydroelectric Complex is the most important infrastructure project not only for the Rostov region, but also for the whole country. The hydroelectric complex under construction will be composed of a shipping lock with a central control room, upper and lower approach channels with mooring-guiding structures, a spillway and earth fill dam, a meandering fish bypass and spawning channel and a fish passage lock, industrial, service, engineering and auxiliary facilities, and housing for operating personnel. To ensure the navigation safety, channel-regulating dams are being constructed, as well as shore protection dams that will prevent the development of bank erosion processes (washout and collapse), protect from the impact of ship waves and reduce the negative impact of waters on the population living in these areas. In order to ensure guaranteed waterway dimensions (depth – 4 m, width – 80 m, bending radius – 500 m) in the section from the Kochetovsky Hydroelectric Complex site at km 3004.5 of the waterway of the Integrated Deep Water System (IDWS) to the Bagaevsky Hydroelectric Complex site at km 3089 of the IDWS waterway, dredging and river cut-off are envisaged.