RU2791119C1 - Method for construction of geotechnical structures in the water area of urban rivers and canals - Google Patents

Abstract

FIELD: underground structures construction.

SUBSTANCE: invention relates to the construction of underground structures in water areas and in the under-channel space of rivers and canals in large cities. Specifically, to the construction of enclosing and load-bearing walls of underground structures constructed using the technology of trench "walls in the ground", impervious curtains, supporting barrettes, etc. in the waters of urban rivers and canals. The method for erecting an underground structure in the water area includes the development of a trench through the foreshaft and the erection of a protective wall in the ground along the entire perimeter of the pit. Floating pontoons are sunk into the soil at the construction site, the equipment is placed on the decks of sunken pontoons, and the foreshaft is formed from the sides of the submerged pontoons arranged parallel to the gap in the water area, or the foreshaft is formed in the gap between the walls of the embankment and the side of the pontoon, or the foreshaft is formed in the gap between sheet pile wall and pontoon board.

EFFECT: increasing the efficiency of work on the development of the under-channel space of canals in cities without harming the ecology of the space, reducing the labor intensity of work.

2 cl, 4 dwg

Description

The present invention relates to the construction of underground structures in water areas and in the under-channel space of rivers and canals in large cities. Specifically, to the construction of enclosing and load-bearing walls of underground structures constructed using the technology of trench "walls in the ground", impervious curtains, supporting barrettes, etc. in the water areas of urban rivers and canals.

There is a known method of erecting an enclosing "wall in the ground" of an underground structure in the under-channel space (Patent No. 2686206, Published: 04/24/2019, Bull. No. 12 "Method of erecting underground structures along the riverbed and canals"). A method of erecting underground structures along a riverbed or canal, characterized by temporary blocking of the water flow of the river or canal by means of a dam, with the launch of the water flow along another existing or temporarily created bypass route, followed by excavation of a dried-up channel and the construction of a foundation on which structures with walls are built on top walls, a floor slab is erected, which is the base under the bed of the river or canal, then the water flow is again let in, characterized in that dams at the beginning and end block the entire water flow of a part of the river or canal in the zone of a bypass route for the flow of the water flow, or an artificial temporary route is created for the flow of the water flow, then this blocked area is drained, after which the bottom is excavated and the construction is carried out along the riverbed or canal, and they first dig a foundation pit and enclose it with walls, and put ceilings on top of the walls. The method involves lowering the groundwater level (GWL) around the projected excavation with subsequent production of work on the construction of the enclosing "wall in the ground" according to the known construction technology in dry conditions.

The disadvantage of this method is the need to strengthen the foundations of buildings and structures on a large area of the surrounding area, as well as the cost of maintaining a low water level for a long time the construction of an underground structure.

There is a known method of erecting an underground structure in the under-channel space without lowering the water level (Patent No. 2770187 Published: 14.04.2022 Bull. No. 11). A method of erecting underground structures in the under-channel space of a river or canal in the conditions of existing development, characterized by temporary blocking of the water flow by means of dams, with the launch of the water flow along a temporarily created route, drainage and dewatering in a selected section of the channel, the subsequent erection of enclosing walls with the placement of equipment at the bottom of the channel , excavation of a pit and the installation of a reinforced concrete foundation and frame, followed by the restoration of the water regime over the underground structure, characterized in that along the banks of the canal, temporary dams are washed or filled, on which technological equipment is placed for the construction of a "wall in the ground", and the construction of longitudinal enclosing walls underground structure is carried out without blocking the water flow, which is passed through the bypass pipes, then the transverse dams are dumped and the transverse walls of the complex are erected from them, then the water is pumped out of the fenced off part of the canal, then the excavation of soil in the pit and construction of the complex structures without lowering the level of groundwater in the surrounding area. The method involves the construction of a temporary or permanent enclosing "perfect" wall in the ground around the entire perimeter of the structure under construction with the passage of water flow through the bypass pipeline, and all work is carried out from the surface of temporary wall dams, and the mark of the top of the foreshafts exceeds the water level in the channel by at least one and a half meters for effective action of the bentonite mortar in the trench, maintaining the stability of the trench walls.

The disadvantages of the known method, taken as a prototype: backfilling or alluvium of temporary dams and their subsequent dismantling is quite expensive, lengthy and laborious operation, because. for the operation of heavy drilling equipment, it is necessary to perform the process of natural or artificial compaction of the soil of the dam. Alluvium inevitably causes water turbidity and worsens the ecological situation downstream.

The technical objective of the invention is to increase the efficiency of work on the development of the under-channel space of canals in cities without harming the ecology of the space.

The technical result is to reduce the labor intensity of work and the environmental burden on the natural environment and surrounding buildings during the construction of a structure such as an enclosing "wall in the ground" of an underground complex in the conditions of the current development of a modern metropolis, excluding alluvial dams for the construction of foreshafts, disruption of the normal functioning of adjacent enterprises and the comfort of residents, violation of environmental requirements for the regime of a water body.

The problem is solved due to the fact that, unlike the known method, which includes alluvial dams, the construction of ground foreshafts in the body of dams, the development of trenches and the concreting of the "wall in the ground" using equipment placed on the surface of dams, in the proposed method, instead of surface concrete foreshafts submersible metal foreshafts are used on the surface of dams.

Moreover, the sides of floating pontoons can be used as the walls of the foreshafts, which are sunk in the place of work and rest with their bottom on the bottom of the channel. At the same time, the elevation of the pontoon deck, where the technological equipment is located, must be at least 1.6 m higher than the water level. or between the sheet pile wall and the side of the pontoon.

The content of the invention is illustrated in figures 1-4. Figure 1 shows a section of the construction site "wall in the ground" on the shore with a pontoon, figure 2 - section along the foreshaft from the sides of two pontoons, figure 3 - section along the foreshaft from the sheet pile wall and the side of the pontoon, figure 4 - plan in Fig.2.

1 - channel or branch of the river

2 - embankment walls

3 - "wall in the ground"

4 - underground Complex

5 - foreshaft

6 - pontoon

7 - soil at the bottom of the channel

8 - deck

9 - water level in the channel

10 - technological equipment

11 - trench

12 - sheet pile wall

13 - reinforcing cage

14 - concrete pipe

15 - end walls of the foreshaft

The peculiarity of the proposed method is to prevent contamination of water in the channel with drilling fluid, such as bentonite clay, while ensuring the stability of the walls of the trench 11 due to the excessive hydrostatic pressure of the drilling mud column with a height of at least 1.6 m above the water level in the channel or WSL. The method is implemented in the following technological sequence. Pontoon 6 is transported by water to the place where the "wall in the ground" is erected, then its hold is filled with water and the pontoon is sunk onto the ground at the bottom of the channel. Foreshaft 5 is formed from the sides of twin pontoons and inventory end walls and will be filled with drilling fluid. Then the soil is developed in a trench through the foreshaft.

An example of the implementation of the method of erecting an underground complex up to 15 m deep in the underflow space of the channel

Canal 1, or branch of the river, is located in the center of a large city. The banks of the canal are limited by concrete walls of 2 embankments. The surrounding buildings are objects of historical development. The depth of the canal is within 2-3 m. It is planned to build an underground Complex 4 in the form of a monolithic reinforced concrete three-level structure below the canal bottom. Requirements of the city authorities: not to place production and household premises on the embankments; prevent lowering of the groundwater level; do not pollute the waters of rivers and canals; perform all work without leaving the water area.

In the water area along the bank of the canal, flooring is arranged on inventory screw piles and household and auxiliary premises are placed. The entire space of the designed underground structure is fenced with a perfect "wall in the ground" 3, buried in the aquiclude layer, to ensure that the WLL does not decrease during the excavation of the foundation pit for the construction of the under-channel Complex. Due to the tightness of the territory, the boundaries of the Complex 4 may not coincide with the boundaries of the canal 1, so the “wall in the ground” 3 in some places can run along the land, embankments, and in some places along the water of the canal. "Wall in the ground" - trench, performed using foreshaft 5. According to the proposed method, the technology of work, equipment and wall design are the same as the prototype, pontoons 6 and foreshafts 5 are special. can be filled with water and immerse the pontoon on the ground 7 at the bottom of the channel in the calculated location of the water area, while the upper part of the deck 8 remains above the water level 9 for ease of placement and operation of drilling and other technological equipment 10. In some places where the "wall in the ground" is constructed in a dry space, the equipment is placed on a pontoon, and the foreshafts 5 are built in the ground in a known way (STO Nostroy 2.5.74-2012 "wall in the ground" device), if by water - using the proposed method. Depending on the place where the topmast is erected in the ground, variants of the method are offered.

A variant of the method: the foreshaft is formed from the side of the pontoon and the wall of the embankment - in the gap - "the side of the pontoon - the wall of the embankment".

A variant of the method: the foreshaft is formed from the sides of two pontoons.

Variant of the method: the wall is erected through the foreshaft in the gap - "sheet pile wall-pontoon board"

Literature

1. Patent No. 2686206 (RU), Method for erecting underground structures along rivers and canals.

2. Patent No. 2770187 (RU), Method for erecting a structure in the under-channel space of rivers and canals in urban areas.

3. A.S. No. 369240 Flooding pontoon for drilling rig E21 7/12, 1973.

4. STO Nostroy 2.5.74-2012 Installation of a "wall in the ground".

Claims (2)

1. A method of erecting an underground structure in the water area, including the development of a trench through the foreshaft and the construction of a protecting wall in the ground around the entire perimeter of the excavation, characterized in that the floating pontoons are sunk at the construction site of the wall in the ground, the equipment is placed on the decks of the sunken pontoons, and the foreshaft is formed from boards of submerged pontoons spaced parallel to the gap in the water area, or the foreshaft is formed in the gap between the walls of the embankment and the side of the pontoon, or the foreshaft is formed in the gap between the sheet pile wall and the side of the pontoon. 2. The method according to claim 1, characterized in that the equipment is placed on a pontoon in the water area.

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