Installation of soil thermal stabilizers using HDD. Examples of technologies used in the construction of the linear part of gas pipelines. Automatic refrigerant charging

Designed for cooling (freezing) soils in order to increase their bearing capacity, as well as to ensure stability and operational reliability of any type of foundation.

Scope of application

during the construction, operation and repair of oil and gas transportation systems;
development of oil and gas fields, as well as supports of overhead pipelines;
during the construction, operation and repair of transport construction facilities, power lines and lighting poles;
during the construction of railways and highways, permafrost curtains, water intakes, dams, ice islands, roads, crossings and other structures for industrial and civil purposes in cryolithozone conditions.

Soil thermal stabilizers are a hermetically welded metal pipe filled with refrigerant with a diameter of 32 to 57 mm, a length of 6 to 16 m or more. It consists of a condenser with fins (above-ground part with a length of 1-2.5 meters) and an evaporator (underground part with a length of 5 to 15 m or more).

The capacitor fin material is aluminum. The number of fins per 1 m/p is about 400 pieces, the fin pitch is 2.5 mm, the fin diameter is 64 and 70 mm, the fin height is up to 15 mm. The heat exchange area of 1 m/n fins is up to 2.2 m².

The work is carried out without external power sources, only due to the laws of physics - heat transfer due to the evaporation of the refrigerant in the evaporator and its rise to the condenser part, where the steam condenses, giving off heat, and then flows down along the inner walls of the pipe.

Thermal stabilizers are divided into two types: single-section and multi-section.

Thermal stabilization technology frozen soils bases and foundations, is an effective measure to protect frozen soils (FFS) from degradation. The use of thermal stabilization technology makes it possible to protect MMG from the effects of nearby fuel-generating objects, to create winter time crossings, roads and ice islands for drilling wells.

The choice of technology (methods) for active thermal stabilization of soils, as well as types and models of vehicles, is determined design features buildings, structures and technological features of their construction and operation. OS and TS are autonomous refrigeration devices, operating due to low atmospheric temperatures during the cold season and not requiring any costs during operation.

To work in Yamal conditions, it is planned to use special materials to strengthen soil surfaces - biomats. This is a complete artificial soil substitute for the period of its restoration.

The biomat is a multi-layer, completely biodegradable base, between the layers of which a reclamation mixture is laid, including seeds. perennial plants, nutrients (mineral and organic fertilizers, plant growth stimulants, soil-forming bacteria) and moisture-retaining components (in the form of synthetic polymers) that improve the soil’s ability to retain moisture.

The use of biomats is aimed at protecting and strengthening the surfaces of soil embankments and slopes, and pipeline embankments. The use of biomat is especially effective in difficult natural conditions in the regions of the Far North, where the natural environment is especially sensitive to external influences, and the ongoing complete or partial destruction of vegetation extremely sharply activates the processes of water and wind erosion and gully formation.

The use of biomats makes it possible to practically restore the soil-vegetative layer already during the first summer season without laying a fertile soil layer and subsequent reseeding of grass.

They are manufactured in industrial conditions and delivered to the site in full finished form. The builders will only have to secure them with the help of special rods at the site of the completed work.

Soil thermal stabilizers.

One of the most important areas reflecting the modern practice of northern construction is the preservation of the traditional state of permafrost soils in the human economic zone. Under this condition, the equilibrium state is maintained environment and the stability of structures erected on these soils.

An effective way to maintain or enhance the frozen state of the soil in the foundations of structures is to use low outside air temperatures using vapor-liquid thermosiphons called thermal stabilizers.

Thermal stabilizers are designed to cool and freeze permafrost soil in order to increase its bearing capacity.

The area of specific use of soil thermal stabilizers is very wide: stabilization of soil in the bases of foundations and structures, bridge supports, pipelines, power lines.

The design of the soil thermal stabilizer is a gravity-oriented heat pipe in which the evaporation-condensation process of heat transfer is carried out using vapors of a low-boiling refrigerant (freon, propane, ammonia, etc.). finned aboveground part is a condenser; the part of the thermostabilizer buried in the ground is an evaporator.

The thermal stabilizer for soil contains inside a sealed housing structural elements, ensuring its stable operation in both vertical and inclined positions.

Polymer lining profile (rail).

The polymer lining profile is designed to protect the outer surface of the pipeline when installing cast iron or reinforced concrete weights (weights), as well as to protect the insulating coating of pipelines from mechanical damage during the process of pulling the pipeline through the underwater passage casing in difficult terrain. Neftegaz profiles can also be used as lining mats under supporting elements and pipeline fittings.

The use of profiles significantly reduces lining time, ensures guaranteed safety of the pipeline insulation coating and extends the service life of the underwater passage. The profile materials are not subject to rotting, are suitable for use in aggressive environments, are environmentally friendly, do not harm the environment and can be used in reservoirs with fresh drinking water.

Geogrid.

The geogrid allows for optimal load stabilization and soil erosion resistance, which ensures a stable soil position.

Geogrid is used in the construction of gas pipelines to strengthen the coastal coastline.

Artificially created embankments that arise during construction or work on construction sites cannot be imagined without the use of proper fixation. In this case, the resistance of slopes can be increased with the help of a geogrid, which will increase the pace of construction of facilities.

The geogrid filler, consisting of a special layer passing between the geogrid and the soil, plays an important role in the reliability of the created structure.

The geogrid restrains the energy of water flows, prevents erosion, and reduces shear forces directed along the slope in the contact zone with the aggregate.

Polymer rock sheet for protecting the insulated surface of pipelines.

The rock sheet is designed to protect the insulated surface of pipelines with a diameter of up to 1420 mm, inclusive, when underground installation in rocky and permafrost soils with sharp fractions, as well as in mineral soils with inclusions of debris, pebbles, and individual stone blocks.

The rock sheet consists of a non-woven synthetic material with a special plastic and at the same time hard coating. SLP is a completely new environmentally friendly coating designed to protect the insulated surface of a pipeline of any diameter. DES can be used in any climatic conditions.

The design of the rock sheet satisfies such basic requirements as:

Ensuring ecological cleanliness of the environment;
Simplification of the pipeline lining process (installation process);
Simplification of the process of transportation and storage;
Does not interfere with cathodic protection.

Polymer container ballasting device is a modernized double design PKBU-MKS.

Polymer-container ballasting device - a modernized dual design PKBU-MKS - is a product that consists of two containers connected by four power strips, as well as metal spacer frames. Such containers are made of soft synthetic materials. For the production of ballasting devices, technical fabrics are used, which are highly durable and ensure long service life in ground conditions. They can be used for ballasting pipelines with a diameter of up to 1420 mm, as well as those structures that float in a flooded trench or are operated in swampy areas, provided that the depth of the trench exceeds the thickness of the peat deposits.

The main feature of PKBU-MKS is the absence of contact between the metal frame and the insulating coating of the pipeline. PKBU-MKS includes the container part of the KCh, represented by one bag, as well as four longitudinal and four transverse pipes - elements of the ERRZh stiffening spacer frames. If necessary, ballasting devices can be combined into groups using couplings. With a pipeline diameter of 1420 to 1620 mm, the group can consist of four devices, and with a diameter of 720–1220 mm - of two.

Thermal stabilization of soils

In recent decades, there has been an increase in the temperature of permafrost soils. This causes risks of the occurrence of beyond design stress-strain states in the soils of bases, foundations, buildings and structures erected on such soils.

This serious problem every year affects an increasing number of facilities operating on foundations composed of permafrost soils (uneven precipitation, foundation subsidence, destruction of structural elements, etc.).

The construction of buildings and structures on permafrost soils is carried out according to two principles:

The first principle is based on maintaining the permafrost state of the soil for the entire period of operation of the building or structure;

The second principle involves the use of soils as foundations in a thawed or thawing state (preliminary thawing is carried out to the calculated depth before construction begins or thawing is allowed during the operation period;

The choice of principle depends on the engineering and geocryological situation. It is necessary to take into account and compare the appropriateness of the principles. The first principle implies that it is more profitable to maintain soils in a frozen state than to strengthen thawed soils.

The second principle is more suitable when soil thawing leads to deformations of the foundation soils, which are within the range of permissible values for a particular building or structure. This principle is, for example, suitable for rocky and hard-frozen soils, the deformations of which are small in the thawed state.

Thermal stabilization of soils

Thermal stabilization of frozen soils is designed to ensure the possibility of constructing buildings and structures according to the second principle.

A number of measures are used to maintain soils in a frozen state. One of the effective and economically feasible methods is to lower the soil temperature using heat stabilizers.

Soil thermal stabilizer (TSG) is a vapor-liquid siphon. This is a seasonal cooling device charged with refrigerant to lower ground temperatures.

TSG is immersed in drilled wells near the foundation to lower the temperature of the soil mass, which is the base of the foundation. Part of the device is an evaporator, which takes heat from the soil, and a condenser, which releases heat into the surrounding atmosphere.

In the thermostabilizer, natural convection circulation of the refrigerant occurs, which passes from one state of aggregation to another: from gas to liquid and back.

The condensed refrigerant (liquefied ammonia or carbon dioxide) naturally, under the influence of temperature differences, falls to the lower part of the TSG to the soil. Afterwards, taking heat from them, it turns into steam and, evaporating, returns to the surface, where it again transfers heat to the surrounding air through the walls of the radiator-condenser and condenses. Then the cycle repeats again.

Refrigerant circulation can be natural, convection-gravitational or forced. This depends on the design of the thermal stabilizer.

The type, design and number of thermal stabilizers are selected based on individual calculations for each object.

Thermal stabilizers have shown their effectiveness - with their help it is possible to maintain soils in a permafrost state and ensure the strength and immutability of the ice-soil slab under the structure.

Convection circulation of the refrigerant is based on the temperature gradient of the soil and the outside air.

During the summer, like

only the temperature of the condenser - the upper part of the thermostabilizer located in the atmosphere,

becomes higher than the coolant temperature,

circulation stops and the process is suspended with partial inertial thawing of the top layer of soil until the next cold snap.

Installation diagrams by installation method and design:

Single borehole thermal stabilizer (OST)

The simplest device that allows installation work both for buildings and structures under construction and for existing ones. OST can be installed both vertically and at an angle of 45 degrees to the surface;

Horizontal thermal stabilizer system (HST) is a system of evaporator pipes located in one horizontal plane in the soil mass, which is the base of the foundation. The refrigerant from the evaporator pipes is transferred to the condenser located on the surface. The installation of a GTS is advisable for new construction, when it is possible to construct a pit;

Vertical system of thermal stabilizers (VST) combines horizontal system, to the evaporator pipes, to which vertical evaporator pipes are connected, going deep into the soil mass. This design allows soil to be frozen to a greater depth than under the GTS scheme. The installation of VST is advisable for new construction, when it is possible to construct a pit;

Thermal stabilizer system, installed at the base of an existing building or structure using directional drilling.

The latter method does not require the development of pits, trenches, or strengthening, and allows the natural structure of the soil to be preserved. It is permissible to install a soil thermal stabilization system in parallel with the construction of the building or structure itself, which speeds up the construction process.

Technical and economic indicators when using soil thermal stabilization

Thermal stabilization of soils using various TSG systems can reduce construction costs by up to 50% and reduce the construction time of facilities by almost 2 times.

"Thermal stabilization of soils" (download in PDF format)

Copying information from this site is permitted only with a link to http://site

The offers posted on this website do not constitute a public offer.

Soil thermal stabilizers are used in the construction of foundations in permafrost conditions, which reduces capital investments from 20% to 50% by increasing the bearing capacity, reduces construction time by up to 50% and construction area by up to 50%, and also guarantees the safety of any complex structure.

General description:

Soil thermal stabilizers are represented by four main types of seasonally operating cooling devices (SCU):

– horizontal natural tubular systems (HET),

– vertical natural tubular systems (VET),

– individual thermostabilizers,

– deep self-propelled guns.

Video:

Soil thermal stabilizers have the following advantages:

The use of these technologies in the construction of foundations allows:

– maintain the required design temperature foundation soils,

– reduce capital investments from 20% to 50% by increasing load-bearing capacity,

– reduce construction time by up to 50%,

– reduce construction area by up to 50%,

– guarantee the safety of any most complex structure,

– ammonia or carbon dioxide is used as a refrigerant,

– Opening hours: October to April.

Application:

– linearly extended objects: oil product pipelines, gas pipelines, technological pipelines, roads, railways, supports of bridges and aqueducts, power transmission line supports, supports of technological pipelines, water pipelines,

– engineering structures: tank farms, gas wellheads, oil wellheads, open flares, sludge pits, solid waste landfills, chemical reagent parks, technical racks,

– buildings: oil pumping stations, gas compressor stations, field support bases, residential complexes, industrial buildings, public and civil buildings,

– hydraulic structures: slope sections of oil and gas pipelines, bank protection, dams, waterworks, dikes, impervious, permafrost curtains.

Horizontal natural tubular (HET) systems:

The HET system is a hermetically sealed heat transfer device that operates automatically in winter due to gravity and the positive temperature difference between the ground and the outside air.

The HET system consists of two main elements: 1) cooling pipes (evaporation part), 2) capacitor block. Cooling pipes located at the base of the structure. They serve to circulate the refrigerant and freeze the soil. The condenser unit is located above the ground surface and is connected to the evaporative part. The capacitor unit can be removed from the object up to 100 m.

The GET system works without electricity in automatic natural mode. In winter, heat is transferred from the ground to the refrigerant in the cooling pipes. The refrigerant changes from the liquid phase to the vapor phase. The steam moves towards the condenser unit, where it again enters the liquid phase, releasing heat through the fins into the atmosphere. The cooled and condensed refrigerant flows back into the evaporator system and repeats the movement cycle. The condensing unit is charged at the factory with the required amount of refrigerant sufficient to fill the entire system. Working pressure in systems is no more than 4 atm.

Vertical natural tubular (VET) systems:

The VET system is an analogue of the GET system, reinforced with vertical pipes. Vertical pipes are placed at the required design points and connected to the condenser unit.

A special feature of the VET and GET systems is the ability to carry out deep freezing of soils in the most inaccessible places or those places where the placement of above-ground elements is undesirable/impossible. All cooling elements are located below the ground surface.

BET and GET systems are designed to effectively maintain a given temperature regime permafrost soils under the foundations of various structures: tanks up to 100,000 m3, automobile and railways, buildings up to 120 m wide.

Individual soil thermal stabilizers:

The individual thermal stabilizer is made as a sealed one-piece welded structure of complete factory readiness, charged with refrigerant, with an underground evaporator part and an above-ground condenser part.

The heat stabilizer is installed vertically or obliquely at an angle of up to 45 degrees to the vertical, in close proximity from the lower end of the piles in the foundations. The evaporative part of the thermostabilizer is located in the ground and has a protective zinc coating.

Designed for cooling thawed and plastically frozen soils under buildings with and without a ventilated underground, under overpasses pipelines and for other structures in order to increase their load-bearing capacity. They are also used to prevent pile buckling.

The total length of the individual thermostabilizer is 6-21 m, the depth of the underground part is up to 20 m, the height of the above-ground condenser part is from aluminum fins - up to 3 m.

Deep seasonal cooling devices:

A deep seasonal cooling device (SDU) is a sealed one-piece welded structure charged with refrigerant.

Carbon dioxide is used as a coolant for deep gas control systems. It fills the entire frozen height of the SOU. Intensive circulation is ensured by the use of special internal devices.

The depth of the underground part, depending on the object to be frozen, can reach 100 m. The height of the above-ground condenser part is up to 5 m.

Deep SOUs are designed for freezing and temperature stabilization of soils of dams and wellheads in order to ensure their operational reliability, highways, freezing of local thawed zones.

Note: © Photo https://www.pexels.com, https://pixabay.com, http://www.npo-fsa.ru. Video https://www.youtube.com/channel/UCc1o05Hz9mZQJ-VFl6YleIg. Photo and video provided by NPO Fundamentstroyarkos LLC, http://www.npo-fsa.ru.

installation of soil thermal stabilizers near thermal chambers of the heating network
soil thermal stabilizers in permafrost conditions installation price buy tsg diagram production of soldering iron sou tk32 operating principle of pvc do it yourself production latest patents

Demand factor 1 546