chimney）
The construction technology of chimney sliding mode and the construction measures of chimney
I. project overview and characteristics
This project for the valley of god biological technology group co., LTD. Power plant chimney project, the project, the chimney height of 120 meters, exit diameter of 3.5 meters, the cushion layer for the C10, basis for C30, drum as a C30, lining for refractory brick acid-proof daub masonry.
This project belongs to the high altitude, the difficulty is big, tall buildings construction and construction technology is complex, but my company has a group of experienced, theory and practice of battle-hardened chimney professional construction team, both in management and the construction technology need to be able to do this project.
Ii. Construction objectives
1. Target: the total calendar works for 120 days, completing the total amount of work.
2. Quality objectives: the acceptance rate of the subsection is 100%, the optimal rate is greater than 90%, and the engineering perception is greater than 85%.
3. Cost objective: ensure the quality and safety of the project, and plan to save 17% of the project cost by means of effective management.
4. Security objectives: adhere to the principle of \"safety first, prevention first\ensure that the general frequency of accidents is less than 1.5 ‰, and the rate of death rate is zero, and the major and major safety accidents are eliminated.
5. Environmental protection goal of civilized construction: strengthen the scientific management of construction site, meet environmental requirements, establish humanistic engineering image, and create municipal construction site.
6. Technical progress goal: the project is listed as a technical demonstration project of the enterprise, and the efficiency rate of scientific and technological progress reaches 1.5 ‰.
7. Service goal: to establish the owner to meet the construction process, and to track the quality of the project for three years.
Construction and deployment
1. Main construction techniques
1.1 the overall template construction is adopted by using the shaft frame.
1.2 construction of concrete pouring and construction of reinforced concrete tube with inner lining.
2. Construction process
Construction preparation - digging - cushion to equipment assembly, foundation of the whole board to backfill, concrete casting tube body and lining concrete casting pouring each paragraph (1.25 m) - thermal insulation masonry each paragraph (1.25 m) - shell concrete casting
Installation of the signal platform, installation of the climbing ladder, the installation of the lightning protection electrical installation, the application of the air sign painting, the removal of the equipment, the construction of the smoke barrier wall, the clearance.
Iv. Main construction technology plan
1. Installation of internal derrick, platform and lifting system
The overall construction process is as shown in figure 1.
1.1 construction of derrick installation
Internal vertical height of 1.25 m, the adoption steel pipe scaffold erection, standing pole level interval of 1.5 m, the level of rail vertical interval of 1.15 m, according to the diameter of chimney set-up, than the degree of its diameter reduced gradually along with the lining size (into the frame after checking see attachment 1). When setting up the steel pipe frame, insert the end of the steel tube into the lining brick
masonry, and place it on the brick masonry (see the figure below:). In the height direction, every 10 m bracket must be around four pole elongation, until both ends of the anchor into the wall concrete 50 mm, with reinforced concrete wall, guarantee and frame strength and stability, in extreme when installation package on isolated cement concrete, so as to avoid the future couldn't open the steel tube (see image below: detailed B).
Chimney construction shaft frame is increased with the chimney wall construction, installation height is beyond + / - 0.000 for the first time in 3 ~ 5 m, the bottom of the derrick bearing based on the concrete floor, foundation concrete surface of the steel plate should be related to cushion flat. When the cage is mounted on the derrick,
Place in a specified silo beforehand. All personnel must be equipped with safety belt and skid insulated shoes when setting up. When the pipe is up, it must be hoisting.
1.2 operation platform construction
The operating platform has two floors, the lower layer is the brickwork binding, the upper layer is the lifting plate, the supporting plate is set, the concrete is used. On the operating table spread 50 x 300 wooden board, wood board and derrick steel pipe with strong brown or 8 wire binding and firm, not a \"blind leap\plank with large gap between the steel tube with a narrow strip or a metal block. The operating table rises with the derrick, and the board is used to prepare three sets of turnover.
In the middle of the well frame, set apart the square hole of 0.9 x 0.0.9 m, and the loading port of the drum, and a 0.2 by 0.2 m hole in the center position, as the hole of the center line of the cylinder in the construction process. Make 1.2 m * 1.2 m sealing plate. After the bucket is up to the platform, it is used to seal the hole and place the wheelbarrow when unloading, and the normal personnel walk to ensure the safety.
There is no outer ring platform on the derrick, and the people who tighten the wire fly only tighten at the outside. When the die and the lifting template, each person is standing in the ring wall of the ring, not outside construction. If the surface quality problem of concrete is needed to be dealt with, the personnel on the external ladder will be processed.
Corresponding position, outside the chimney so we have set up a 3.8 m high external gym, can facilitate the relevant personnel security through the chimneys of the ladder, the ladder up to the platform in the plugin, for the construction and quality inspection. This is shown in the figure below.
Description:
1. The platform and the platform of the platform and the protection platform
4. Corner pulley 5
7. Place all kinds of power distribution boxes and tools in the tent, and cover with asbestos tiles to prevent rain, sun
protection, and
Set the lightning rod to connect with the steel tube frame lightning protection system to prevent lightning.
Operating platform and external ladder diagram
1.3 internal and external lifting system construction
The vertical lifting device in the chimney USES 5t hoist, with a diameter of phi 14 wire rope, through the bucket. The bucket is round, welded with 6mm thick steel plate, high 700mm, the bottom diameter of 650mm, the outer diameter of 750mm, the base plate is fixed with pin shaft, can turn up and down the sealing material or open the unloading material up and down. During the construction process, check the flatness of the base plate regularly, and put the steel bars, steel pipes and fastening pieces in light, so as to avoid the deformation of the base plate and the slurry leakage.
Due to the high difference between the existing ground and the plus or minus 0.000, a small steel tubular gantry frame will be set up at plus or minus 0.000, and the lifting equipment of the gantry frame will be equipped with a 3t hoist with a diameter of phi 14 wire rope. The vertical lifting equipment of the external gantry derrick adopts the 3t hoist, which can be used up and down.
By cart or artificial will be transported to the gantry steel, concrete, etc, on the stage of the gantry to flue platform, inside the safe passage of the flue platform and level transport
in the chimney derrick, level and vertical transformation. The steel bar, steel and concrete are hoisting to the upper part of the construction platform with the hoisting barrel in the derrick, and the opening of the letter is sealed with the platform. Remove the steel and steel pipe, and transfer it to the necessary part of the binding, remove the concrete into the wheelbarrow, and push it to the concrete pouring site and pouring.
Derrick and gantry with increased within days pulley installed on the top of the derrick pulley fixed on the shelf, pulley fixed with four to eight root diagonal reinforcement, bearing, at least eight fasteners on the slider moving load is: 2 x 1 t = 2.6 t, and the dynamic load in each fastener is: 2.6 8 = 0.325 t/t (3.25 KN), can satisfy completely the requirements of bearing capacity. Here is the diagram below.
Sky slide bar, floor plan
The lifting speed is 30-440m/min (round trip to 3-5min), or 60m/min (around 3min back and forth), at least 120m in volume and at least 250m in length. 3t hoist requirements: the lifting speed can be 30-440m/min (1 min back and forth).
The 3t winder USES Angle steel to hold the anchor pile, 5t winch with 13mm steel wire rope to anchor the beam, plate and column of flue, and remove the beam, plate reinforcement and welding anchor hoist frame.
1.4 construction of protective shed
Derrick inside the chimney, high set 5 m place a double protective casing, to prevent the upper construction objects falling, ensure the safety of construction personnel under the shaft frame work station under full load, and used for vertical transportation. A safe passage is set up on the flue platform and a double protective shed at the top of the channel. And the outer longgate lifting roof has a double protection shed. Double layer protection shed with two floor space of 500mm. See figure 1.
2. Concrete construction of chimney
It adopts round-the-clock operation, with 50 employees working in rebar, carpentry, welder, electrician, concrete work and machine operator every day to ensure the progress of the project.
Tube body construction quality requirements: in construction engineering, must ensure that the tube body center verticality deviation is not more than 60 mm, wall thickness error of less than 20 mm, tube body radius error on any section shall not be greater than 1% of the radius, and no more than 30 mm. Smoke crossing of centerline deviation shall not be greater than 15 mm, elevation deviation of flue within 20 mm, inside and outside wall and on the back of the local uneven, shall not exceed 1% of the cross section and not more than 30 mm, smoke crossing shall not be greater than 30 mm, height and width is not less than 20 mm.
2.1 construction of the shift template
2.1.1 the structure of the moving template
The outer mold of the barrel is made of 2mm thick, 1000 x 200 m of white sheet metal, each sheet metal processing is divided by the charge. Each set of templates set aside 1m on both sides. The scores were received twice, at a height of 1.25 metres. The outer surface of the chimney can be clean, beautiful and fast, and the body of the tube is the same.
Template used in brick lining and wedge, the combination of steel template: masonry chimney lining first, between the lining and steel bar, put inside steel template, reoccupy deformation fir processed into the same wedge batten with air thermal insulation layer thickness, material measures, in between steel and brick masonry, the formation of air thermal insulation layer. The wedge-shaped wood is made of 3cm thick wood in the woodworking planer. Since the air insulation layer is 100mm and 50mm, the wedge is divided into two kinds, one is 75mm and 25mm, the other is 30mm and 20mm. In the construction, bricklaying in 6 ~ 3 hours, there is a certain time to prepare for internal model, therefore, the time interval for bricklaying and internal model is in commonly 4 to 7 hours, and pouring concrete extremely slowly,
The strength of mortar can withstand the construction load of internal mold and concrete.
Template according to our company for many years practical experience, the use of 2 mm thick tin according to the outer wall of the chimney dividing divide into four groups, each group of all points on both sides to set aside the template, according
to the distance between 2 m in the upper portion of the plate in each group, namely every other piece of board welding ascension template with phi 14 steel hook. The two iron sheets are drilled with electric drill, and anchored by anchoring screw. The anchor screw is made out of the inner surface to make the inside of the metal surface flush with the metal surface, and the connection is welded by welding spot. In each sheet metal, connect 250mm to the seam, welding two lines of wire rope connector, in order to wear the steel wire rope in the fastening formwork, tighten the external mold when casting concrete. Will 18 to 28 lifter stents form a complete set of 18 to 28 lifter (1 t) installed on the vertical reinforced with the operating table, with concrete to form removal strength after 1.2 n/m ㎡, with uniform outside the lifter will die one day.
The inside and outside templates are bound or welded to the steel bar of the cylinder wall with a steel bar of 12, to ensure the net spacing of the internal and external modes and the thickness of the inner and outer coatings. The length of the steel bar and the thickness of the cylinder wall. Place the spacing along the circumference of the circle at @250mm.
Weld with phi 25 steel bars as shown in FIG. 2, and tie the steel wire with three - four - four - to - four - wire to the vertical steel bar. The load on each lifter is (considering the dynamic load coefficient 1.4) :
1.4 x (41 * 1.35 * 0.00127 * 0.00127 * 103 + 18 * 36 * 18/100) 28
638.03/28 = 1.4 x = 31.9 x 10-2 kn
This force is relatively small, the 1t lift and the lifting frame with phi 25 steel welding can be completely bearable.
2.1.2 installation of the shift template
Internal template installation: before installing the inner mould, masonry the brick masonry lining of the chimney, and determine the center line and the radius, so as to control the installation radius of the internal template and the fixed template. After putting in the inner steel plate, a wooden wedge is added between the lining and the steel mould (a set of wood wedge thickness is consistent with the thickness of the air insulation layer), and the steel mould is supported with wood support. The wooden wedge is placed in a circle in the direction of 100mm in the direction of the circle. The wooden support is set up and down according to the position of the inner die sheet. When concrete is cast, then remove it.
Mould installation: external mold installation calibration after reaching the size of the requirements, use temporary brace design wall thickness control template net distance, both inside and outside and outside mode and the main mode of protective layer spacing, tie every one put a tin, when the concrete pouring to temporary brace, gradually to be dismantled. After the external mould is installed, the outer ring shall be fastened with 18 6.5 mm wire rope and the wire rope. The outer template should be tightly packed, and the gap should be tightly closed to prevent the opening and leaking. The inner template shall be supported firmly. Prevent deformation.
The lifting of the template has 18 ~ 25 hoisting frames to improve the lifting gear.
The center of the displacement type template for chimney geometric center of the bit error rate not more than 5 mm, edge of the template with concrete lap is about 100 mm, the template contact concrete side after each removed, cleared of slurry ash on the surface of the template, and brushing release agent.
Should determine the center position of tube body inspection, mainly USES the laser alignment instrument, will and review on the use of the apparatus, the center of the total station to put on after the leveling, open the laser beam, a draw of laser on the top frame plate, again according to the laser spot center,
Pull gauge to check radius. The vertical degree of the chimney is reviewed for the vertical scale of the chimney with a weight of 20kg. The vertical ball is mounted on the frame of the frame and the vertical ball is hoisted up and lowered.
2.2 reinforcement construction
The vertical reinforcing bars and circular reinforcing bars are attached with the tie, the length is 45d, and the wire is in the middle and the two ends of the joint. Any horizontal ring with a diameter of more than 12 mm shall be made into an arc in the shape of the tube in the radian of its position. The steel bars of 12 mm are only curved at both ends. The arc can bend at the binding. When binding the reinforcing bar, tie up the bar and bind the band.
A hooped on each cylinder body is the most should be the first position, will be subject to have the edge of the casting concrete template, press the up close degree, at the same time considering the thickness of the protective layer to locate, thread hammer hanging position, bound and fixed, and then to ring ribs for the standard tie the following ring ribs.
Tube body of the vertical steel bar from the center of the tube body, after the steel quantity according to the requirements of the drawings standard radius uniform distribution, the vertical reinforcement by the head of staggered distribution within each level section, not greater than the total number of reinforced 25%, welded joint number should not be more than 50% of the total steel, transform the diameter of the longitudinal reinforcement or root number, should be concluded within the full circumference of uniform cloth on. The cylinder ring shall be arranged on the outside of the longitudinal steel bar, and the allowable deviation of the spacing shall be 20mm. All rebar intersections are tied with the 22 wire.
Reinforced protective layer made from wood pull the son, from the center line of the quasi radius with Mr. Silk tie is good, keep the template perimeter in per meter length of not less than 0.5, and compared.in ring to reinforced concrete protective layer thickness of 30 mm, tube body protection layer of deviation shall not exceed + 10 mm and 5 mm.
The longitudinal reinforcement of the above template shall be fixed temporarily by the two ring bars. After each layer of concrete has been cast, at least one of the binding rings should
be kept in it.
2.3 concrete construction
2.3.1 concrete materials
The concrete mixture ratio test must be done in the entry of the concrete mixture ratio test with the standard 42.5 ordinary Portland cement, which must have the variety label, the material origin, the factory date and other quality documents. The coarse aggregate can be used to use the treasure spring 5 ~ 31.5 mm igneous rock gravel, cannot use the weathering, the largest
The particle size should not be larger than 40mm, the content of mud content should be less than 1%, and the aggregate will use the sand (fine modulus MX = 1.21), and the mud content should be less than 3%. Water is used in the factory. Concrete water cement ratio is not greater than 0.5. In order to ensure the quality of the project and speed up the construction progress, ensure the safety of construction, the sf-2 high efficiency and early strength of the peak of 0.6 % of concrete are added.
2.3.2 concrete casting
Before pouring concrete, must review the size of the template, check the elevation, position and quantity of various embedded parts, and make sure that the concrete can be cast in the rear.
At the scene set a 500 l forced mixer, concrete mixing, transporting by cart to external longmen derrick, ascending to
flue platforms, then push to the mast, casting by derrick in ascension to the platform. Concrete should be started at about two little running evenly stratified concrete circular section, two way after meet, then reverse pouring, layered ceaselessly so, each layer with 50 type vibrator concrete vibratory compaction. Concrete layered casting,
The height of each layer is about 250-300mm. When pouring concrete, the casting direction should be changed
symmetrically to prevent the plate from tilting and twisting in one direction. When vibrating concrete, it shall not touch the steel bar and the template. The insertion depth of the vibrating rod should not exceed 50 mm in the previous layer of concrete. When lifting the template, the concrete shall not be tamped. For the treatment of the construction joints, remove the loose stones first, rinse clean, and then spread the cement mortar layer of 20-30 mm thick and then continue pouring the concrete. The concrete and steel bars should be cleaned when they are stained with oil.
The tube shall be placed at 5m height each, and a set of concrete test blocks shall be made to indicate the date of sampling to test the strength of concrete at the age of 28. During the first pouring, several groups of test pieces are made to test the strength of one day, two days and three days respectively for reference. The special person shall be responsible for the production, maintenance and inspection of concrete test blocks. The surface of the concrete and the joints must be smooth and smooth. No honeycomb surface and obvious construction joints can be found.
2.3.3 curing and dismantling
The removal of the outer template of the tube shall be carried out in the strength of the concrete to withstand the load of the upper load without deformation, and the strength of the concrete shall not be less than 0.8mpa. The bearing template of the pipe shall be removed after the concrete strength reaches 70% of the design mark. After the removal of the template, the surface should be repaired in time, and the water should be watered and maintained. It should be kept wet, and its duration should not be less than seven days and nights. The wall concrete can also be maintained by thin film curing agent. Curing water, because the water pressure is not high, so the need to install a pressure pump, with phi 50-60 pipe water to the top of the derrick, and with the increasing of derrick and the high, since the hose down water diversion to the circumference of tube be located outside hanging ladder phi around 25 mm rubber hydraulic pipe, water spray on drill spacing between 120-120 - mm phi 3-5 mm blowhole, wet curing.
3. Construction of chimney accessories
The pre-buried parts of the concrete chimney of reinforced concrete chimney and the signal station should be put in front of the concrete, and the steel reinforcement shall be used to bind and weld the two kinds of reinforcement in the outer reinforcing bar. The location of the ladder is allowed to be 20mm and the deviation of the signal station is allowed to be 10mm. The thread of the embedded part should be properly protected and not defiled, and the thread of the embedded part should be covered with butter so as to avoid the concrete slurry
entering. When the metal parts are installed, the exposed part should be coated with anti-rust agent before installation. After installation, the external parts should be connected, and then the rust inhibitor will be applied again. The bolts of the chimney accessories should be tightened and must not be omitted. Up and down the ladder and fences to is, attached when installation, the strength of the concrete must be at least 1.2 N/m ㎡. The parts of the chimney arrester should be welded firmly, and its grounding pole should be buried in the backfill of the foundation pit. After the arrester installation is completed, check the grounding resistance and its value shall not exceed the design requirements of 10 ohms.
4. Lining construction
It is necessary to ensure the quality of lining masonry and the location of the insulation layer. The upper surface of the ring cantilever with inner lining is applied to the surface of cement mortar and the horizontal deviation shall not be greater than 20mm. The lining layer shall not be allowed to remain straight, and the mortar in the masonry must be full. The full measure of horizontal ash seam: ordinary clay bricks shall not be less than 80%; Clay and refractory bricks must not be less than 90%. Vertical grey seams should be used for pulping and grouting.
Plump up the mortar.
The thickness of the inner cement is allowed to increase the value and the quantity of the crack is allowed
Type grey seam thickness of the lining
(mm) the thickness of the ash seam
The increase value (mm) is 10 on the surface of 5
To increase the number of ash joints (place).
1 common clay brick and diatomite brick 8 + 4 7
2 clay refractory brick and acid-proof brick 4 + 2 5
When the thickness of the inner lining is 1/2 brick, the brick will be made of brick masonry, and the brick will be interleaved with brick. The seam of the inner lining should be flat, the inner lining should not be more than 1% of the inner radius in a week, and the maximum should not exceed 50mm. The thickness of the insulating layer between lining and barrel is 100mm and 50mm respectively. To maintain the stability of lining, every square metre inside lining to pick out the two top brick wall direction, set aside 10 mm between roof tiles and wall temperature, at the same time outside the lining surface by the longitudinal spacing of 2.0 m set a circle anti-settling belt, anti-settling band and compared.in leaves 10 mm between the temperature of the seam. When building masonry, it is necessary to pay attention to mortar consumption, and avoid slurry falling into the air heat insulation layer.
5. Chimney decoration construction
Chimney section 95 m - 120 - m concrete surface brush red, white and white flag ring, design for durability of coating or paint,
logo ring 5 m wide, brush red elevation above 115 m steel platform, ornamental design groove tube body blush white, by construction professionals, out on the cantilever beam suspension besmear to brush. When brushing, should wait for the concrete surface to dry, in the 20mm depth of moisture content is not more than 6%, the surface of the surface of the ash and grease and so on clean. The preparation and construction of anticorrosive coatings shall be carried out in accordance with the relevant regulations of the state.
6. Demolition construction of shaft stand
Should have professional personnel to command, demolish by skilled personnel to demolish. Top-down removed one by one, step by step down in the rise of the order of construction, first under the upper platform will be transferred to the lower platform, and shop is good, and then removed the pipe rack, keep day slider frame, material barrel down the dismantling of pipe fittings, when the demolition of a part, should prevent other parts fall, railing ladders should cooperate with the whole demolition, shall not dismantle bearing first column, beams, to wait for it to dismantle rear can dismantle all structure. The pipe fittings that have been anchored into the concrete, such as the ones that cannot be removed, are cut off, and the steel pipe holes are sealed with fine stone concrete. To be able to draw out, then the C35 fine stone concrete sealing hole. Block the edge of the brick hole left by brick and M7.5 mortar.
7. Settlement observation construction
Settlement observation point, buried in the wall lateral
elevation 0.44 meters, set in the line of the two perpendicular four view observation point, concrete intensity reached 1.2 N/m ㎡, may begin to open mold, installation of settlement observation point. After the installation is completed, the observations are made and detailed records are made. After completion of the project, the project is filed for inspection and continued observation.
Special climate construction
8.1 rainy construction
In order to ensure the construction progress of the project, it is not very important to carry out the construction on rainy days, and all personnel wear raincoats and waterproof shoes. Cover all electrical equipment with plastic cover and protect the rain. On the construction platform, set up temporary shelter from rain. As shown in the previous figure. 8.
2 lightning weather
This area is a strong lightning measure and must be feasible. , derrick Peng rack installed lightning rod at the top of the slider, downlead underground ground from chimneys. The lightning rod is set up in the rainproof shed. It is connected with the lightning protection system of the inner well frame. Once the lightning weather is encountered, all the construction personnel are in the shelter to avoid it, and the construction can be put out after the weather is stable.
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