RU2299949C1 - Method for upstream structure construction in permafrost ground and upstream structure - Google Patents

Abstract

FIELD: hydraulic building, particularly barrages or weirs, layout, construction, methods of, or devices for making same, for instance in northern zones characterized by permafrost areas.

SUBSTANCE: method involves constructing drainage device, upstream structure and leakage water accumulation vessel, which collects water penetrated through upstream structure body and base; excavating freezing trench downstream of leakage water accumulation vessel on the path of underground leakage water flow filtered through the vessel; providing the trench with shed to protect thereof against atmospheric precipitations. Device for above method realization comprises draining means and leakage water accumulation vessel. Device also has at least one freezing trench located downstream of the leakage water accumulation vessel and arranged on the path of underground leakage water flow filtered through the vessel. Freezing trench is spaced a distance from leakage water accumulation vessel. The distance is enough to retain pillar between the vessel and the trench in natural condition over time period between winter seasons. In particular cases the trench is provided with removable protective covering, tube and cold air source or packed coolant, as well as with shed to protect thereof against atmospheric precipitations.

EFFECT: prevention of underground flow filtered through leakage water accumulation vessel diffusion and improved water-tightness of the structure.

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Description

The invention relates to hydraulic engineering and can be used in the operation of pressure head soil hydraulic structures in northern climatic conditions, characterized by the presence of permafrost soils.

The regions of the Far North are also characterized by the absence of natural soil antifiltration material, which gives specifics to construction work and increases their cost.

To reduce and prevent filtration losses through the body and the base of the pressure structure, various designs of pressure structures, including drainage devices and various anti-filter elements, are used, and various construction methods are used.

So, there is a method of erecting an anti-filtration element of a pressure structure in the form of a dam in harsh climatic conditions, in which frozen soil is loosened in a quarry and crushed. Then cooled chilled fine aggregate and Portland cement are introduced into it. The prepared mixture in the frozen state is placed in the body of the anti-filter element and rolled to the required (maximum) density. During thawing, excess clay soil moisture is spent on hydrolysis and hydration of cement, as well as on wetting and adsorption of fine-grained aggregate. Consolidated soil cement after thawing provides the necessary suffusion-filtration and deformation stability of the antifiltration element [AC SU 1518441. Bull. No. 40 10.30.89].

The disadvantage of this pressurized structure is that its constructive solution does not provide for the interception of an underground passage of water filtered through its base, which leads to adverse environmental consequences.

There is also known the northern method of erecting a soil dam, which provides for tiered filling of a soil antifiltration element from frozen cohesive soils, erection of an antifiltration element and the device of a feeding trench between antifiltration elements. When erecting thrust prisms from disconnected soils, water is supplied to the crest of each tier, while water is supplied to the contact zone of the thrust prism and the anti-filter element. Water is also supplied to the feeding trench and discharged. The antifiltration element is arranged by freezing the soil for a period of stabilization of the strength of the body of the structure. After that, the freezing system is turned off [AC SU No. 1476049. Bull. No. 16, 04/30/89].

The disadvantage of a hydraulic structure constructed by this method is the high cost of its construction and the possibility of an underground breakthrough of filtered water below the device for collecting filtration water.

A known method of erecting a soil dam, including the implementation of up to a predetermined intermediate level from a bound soil of an anti-filtration element and from unbound soil of side prisms, forming a layer of unbound soil of a given thickness above them and performing an anti-filtration element within the thickness of this layer by filling the trench developed by an earth moving machine with connected soil the entire thickness of the layer of incoherent soil, while in the incoherent soil part of the layer located above the anti-filter element By entent, immediately at the beginning of the frosty season, humidity is provided in an amount sufficient to homologize this soil during freezing, and the development of the trench and filling it with cohesive soil is carried out at the end of the frosty period and / or at the beginning of the frost-free period [Application RU No.2000108903, 04.10.00] .

Like the previous analogues, the pressure structure using this method solves the problem of increasing the anti-filtering efficiency only due to the design of the anti-filtering element and does not provide for intercepting the underground breakthrough of filtered water through a tank for collecting filtering water such as a drainage well.

Thus, the designs of pressure structures of the previous generation do not provide for the probability of defrosting the bottom and walls of the tank for collecting filtration water during operation and, accordingly, filtering water through them.

The objective of the invention is to develop a method of building a pressure structure in the northern climatic zone, characterized by permafrost, and the construction of a pressure structure that prevents the spread of underground filtering stream, filtered through a container for collecting filtering water.

Technical results that can be obtained using the invention are:

- the creation of a natural water seal between the tank for collecting filtration water and a freezing trench for the period between the winter seasons;

- preventing the spread of the filtration stream being filtered through a container for collecting filtration water;

- increase the antifiltration efficiency of a pressure structure.

The solution of this problem and the achievement of the above results became possible

- for the method: due to the fact that in the known method of building a pressure structure in permafrost soils of a natural base, including the construction of a drainage device, a pressure structure and a container for collecting filter water filtered through the body and base of the pressure structure, they are torn off behind the container for collecting filter water a freezing trench along the path of the underground filtration stream, filtered through this tank, to maintain in a natural frozen the condition of the pillar between this tank and the freezing trench between the winter seasons and equip it with an anti-fall canopy,

- for the device: due to the fact that the pressure structure in permafrost soils, including a drainage device and a reservoir for collecting filtration water, allowing interception of filtered water through the body and base of this pressure apparatus, contains at least one freezing water behind the reservoir for collecting filtration water a trench located on the path of the underground filtration stream filtered through this tank, at a distance from the tank for collecting filter water, sufficient to maintain in the natural state of the pillar between this tank and the freezing trench between the winter seasons.

In particular examples of the pressure structure, the anti-fall canopy is made of reflective material, the freezing trench is additionally equipped with a removable protective coating, a source of cold air, a pipe for supplying cold air or packaged refrigerant.

The invention is illustrated by the following drawings.

Figure 1. A section of the inventive pressure structure, which shows a dam, a reservoir for collecting filtration water, a drainage pipe, a freezing trench.

Figure 2. A fragment of a pressure structure, which shows a freezing trench with an anti-fall canopy and a pillar.

Figure 3. Freezing trench with anti-fall canopy, removable protective coating and cold air pipe.

The inventive pressure structure of local materials in the northern climatic zone (Fig. 1) is made in the form of a dam 1 on a natural base 2 of permafrost soils and includes a drainage device (not shown) consisting of drainage (not shown) in the base 2 of dam 1, and a container for collecting filtration water 3 filtered through the body (not shown) and the base 2 of the dam 1. The drainage is made in the form of a trench 4, dug under the base 2 of the dam 1 perpendicular to its axis. A perforated pipe 5 is laid at the bottom of the trench 4, the end of which extends into the reservoir for collecting filtration water 3. Behind the reservoir for collecting filtration water 3, a freezing trench 6 is arranged along the passage of the underground filtration stream filtered through this reservoir, which is capable of creating a natural water seal by keeping the frozen pillar 7 in its natural state between the reservoir for collecting filtration water 3 and the freezing trench 6 during the period between the winter seasons, which allows wish to set up to prevent the spread of filtration through the container during operation. The freezing trench 6 is filled with cold air (not shown) and equipped with an anti-fall canopy 8, which ensures that the cavity (not shown) of this trench is kept dry. When the walls of the freezing trench 6 are thawed during operation, it is possible to construct another similar trench behind it.

In private examples of the pressure device, a reflective material can be used as a material for the anti-precipitation canopy 8, which further protects the air, which is filled with the freezing trench 6, from overheating under the action of the sun. To maintain a low temperature of cold air in the cavity, the freezing trench 6 can be equipped with a pipe 9 laid along the length of this trench (Fig. 2) and a cooling system (not shown) for forcing cold air through the pipe 9 or with packaged refrigerant (not shown) , which is used as an additional reserve during a period of sharp warming. In addition, the freezing trench 6 of the pressure structure can be additionally equipped with a removable protective coating 10 to prevent rapid thawing of the soil adjacent to its walls and rainfall.

The inventive method of building a pressure structure in the form of a dam 1 from local materials in the northern climatic zone, characterized by permafrost soils, is as follows. Remove the surface layer from under the base 2 of the dam and the tailings bowl (not shown), including organics to a depth of about 0.5 m.

Under the base 2 of the pressure structure in the form of dam 1, a drainage device is constructed, including drainage (not shown) and a reservoir for collecting filtration water 3. To perform drainage, break through perpendicular to the axis of dam 1 to a depth of about 2 m with a trench 4 about 1 m wide. At the bottom of the trench 4 lay a perforated drainage pipe 5, for example, asbestos-cement, the end of which is discharged into an open container for collecting filter water 3, which is filtered through the body (not shown) and the base 2 of dam 1. Trench 4 is filled with gravel and pebble soil and coated with geotextiles (not shown). Protect geotextiles with gravel from damage during further technological operations. Dam 1 is being erected using local materials. The compaction of soils sprinkled into the dam body is carried out using mechanisms used in construction.

Behind the reservoir for collecting filtration water 3, a freezing trench 6 is torn off, which is placed on the path of the underground filtration stream filtered through this reservoir. An anti-precipitation canopy 8 is constructed over the freezing trench 6, which prevents precipitation from entering the cavity of this trench and, accordingly, increasing the temperature of the air in it. The cold air in the freezing trench 6 maintains the pillar 7 in its natural frozen state between the winter seasons, which allows creating a natural water-stop on the path and preventing the spread of the filtration stream by freezing it.

The practical applicability of the claimed invention is shown by the following model examples.

Example 1

When constructing a pressure structure in the form of a dam from local materials in the conditions of permafrost soils for a tailing dump, in the experimental section, soils are developed from under the dam base and tailing bed to a depth of 0.5 m. Under the dam base, perpendicular to its axis, tear off to a depth of about 2 m a 1 m wide trench, a perforated asbestos-cement pipe is laid at the bottom of the trench, the end of which is discharged into a container for collecting filtration water. They fill the drainage trench with gravel and pebble soil, cover them with geotextiles and protect them with filter soil.

The dam is erected to a height of 4 m by compaction of the developed soils with the mechanisms used in construction.

The antifiltration element is carried out by laying the tailings of the concentration plant in the core of the dam in 0.5 m layers with their subsequent compaction by soaking in order to thaw the existing ice inclusions.

After the anti-filter element is installed, the uphill slope is loaded with soil.

A freezing trench is breached at a distance of 5 m behind the reservoir for collecting filtration water. The depth of the freezing trench is 5 m, width 2 m, length 20 m.

The average temperature of cold air in a freezing trench in the winter, degrees C. 35.0 The average temperature of cold air in the freezing trench in the summer, degrees C. 4,5 The average temperature of the rear sight in winter, degrees C 10 The average temperature in summer by the end of the season, city C. 3.0

Example 2

According to example 1.

As a pressure structure, a dam without an anti-filtration element was built.

The freezing trench is protected by an anti-fall canopy of reflective material. In summer, the freezing trench is covered with a removable protective coating to prevent the rapid thawing of soil adjacent to the walls of the trench.

The average temperature of cold air in a freezing trench in the winter, degrees C. 35.0 The average temperature of cold air in the freezing trench in the summer, degrees C. 5.5 The average temperature of the rear sight in winter, degrees C 10.0 The average temperature of the rear sight in summer to the end of the season, degrees C 4.0

Example 3

According to example 2.

A pipe connected to a source of cold air is laid along the bottom of the freezing trench

The average temperature of cold air in a freezing trench in the winter, degrees C. 35.0 The average temperature of cold air in the freezing trench in the summer, degrees C. 5.5 The average temperature of the rear sight in winter, degrees C 10.0 The average temperature of the rear sight in summer to the end of the season, degrees C 4.0

Example 4

According to example 2.

For the period of raising the air temperature above the average freezing trench is filled with packaged dry refrigerant.

The average temperature of cold air in a freezing trench in the winter, degrees C. 35.0 The average temperature of cold air in the freezing trench in the summer, degrees C. 5,0 The average temperature of the rear sight in winter, degrees C 10.0 The average temperature of the rear sight in summer to the end of the season, degrees C 5,0

As can be seen from the presented examples, the claimed combination of essential features of the claimed invention allows us to solve the problem and to ensure during the operational period to prevent the spread of the underground stream filtered through the filter water collection tank, by maintaining the frozen pillar in the natural state between the winter seasons with cold air filling the freezing trench additionally constructed on the way of this flow, i.e. to increase the antifiltration efficiency of a pressure structure.

The inventive step of the claimed technical solution is to prevent the spread of the underground stream, filtered through the reservoir for collecting filtration water, by freezing it year-round by maintaining the frozen pillar between the reservoir and the freezing trench in its natural state.

Claims (7)

1. A method of constructing a pressure structure in permafrost soils of a natural base, including the construction of a drainage device, a pressure structure and a container for collecting filtration water filtered through the body, and the base of this pressure structure, characterized in that a freezing trench is torn off behind the container for collecting filter water along the path of the underground filtration stream, filtered through this tank, to maintain the pillar in its natural frozen state between the container for collecting leakage water and freeze trench between the winter season, and it is equipped protivoosadkovym canopy. 2. Pressure structure in permafrost soils, including a drainage device and a reservoir for collecting filtration water, providing the ability to intercept the water filtered through the body and the base of this pressure reservoir, characterized in that it additionally contains at least one freezing water behind the reservoir for collecting filtration water a trench located on the path of the underground filtration stream, filtered through this tank, at a distance from the filter collection tank water sufficient to maintain the pillar in its natural state between this tank and the freezing trench between the winter seasons, and an anti-precipitation canopy over the freezing trench. 3. Pressure building according to claim 2, characterized in that the anti-fall canopy is made of reflective material. 4. Pressure building according to claim 2, characterized in that the freezing trench is additionally equipped with a removable protective coating. 5. Pressure structure according to claim 2, characterized in that the freezing trench is additionally equipped with a source of cold air. 6. Pressure building according to claim 2, characterized in that the freezing trench is additionally equipped with a pipe for cold air. 7. Pressure building according to claim 2, characterized in that the freezing trench is additionally equipped with packaged refrigerant.

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