CN112523222A

CN112523222A - Method for pouring concrete into pile hole of deep foundation pit of garbage bin of environment-friendly power plant

Info

Publication number: CN112523222A
Application number: CN202011437698.5A
Authority: CN
Inventors: 冯洪春; 徐敏
Original assignee: PowerChina Sichuan Engineering Corp Ltd
Current assignee: PowerChina Sichuan Engineering Corp Ltd
Priority date: 2020-12-07
Filing date: 2020-12-07
Publication date: 2021-03-19

Abstract

The invention provides a pile hole concrete pouring method for a deep foundation pit of a garbage bin of an environment-friendly power plant, which specifically comprises the following steps: step 1, planning underwater pouring concrete, after a pouring guide pipe is placed, secondarily cleaning holes, inserting air holes with 1m long pipes at the head into the guide pipe, enabling the minimum distance between the bottom of an air pipe and the bottom of the guide pipe to be 2m, spraying compressed air from the bottom of the air pipe, cleaning residues of pile holes with the depth of less than 10m by using an air suction pump, ensuring that the thickness of the residues at the bottom of the holes is less than or equal to 50mm, adopting C30 commercial concrete for the concrete, enabling the concrete slump to be 180-fold and 220mm, stirring and transporting at a concrete transportation position, and adopting an arm support pump for supporting piles to pour the concrete. The invention aims to effectively ensure that the concrete pouring quality meets the relevant requirements of the building construction standard by adopting an underwater concrete pouring mode due to the fact that the excavation depth of the foundation pit of the garbage bin is deep, the field of the project is also the lowest-lying area, the pile hole depth is deep, a large amount of accumulated water exists in the hole after the hole is formed by rotary digging, and the concrete pouring is carried out.

Description

Method for pouring concrete into pile hole of deep foundation pit of garbage bin of environment-friendly power plant

Technical Field

The invention belongs to the technical field of electric power engineering, and particularly relates to a method for pouring concrete into a pile hole of a deep foundation pit of a garbage bin of an environment-friendly power plant.

Background

At present, environmental pollution is more and more severe, and environmental protection departments are forced to increase the strength of controlling the total consumption of coal under the condition of haze weather of two-in-three and to support the development of matched environmental protection industries. The rapid development of economy also has an annoying consequence, namely that the amount of waste is also growing rapidly. As the commercial value of land is continuously increased along with the process of urbanization in China, cities are not enough to provide more land for landfill of garbage and how to change waste into valuable, so that secondary development of energy is realized, and the use of the garbage for power generation is a good solution, so that the urban domestic garbage is treated, and energy necessary for life of people is provided.

The waste incineration environmental protection power plant is a good scheme of effectively administering rubbish, but in the construction rubbish power plant in-process, because project rubbish storehouse foundation pit excavation depth is darker, this place of stage is also the lowest low-lying section in addition, and the stake hole depth is darker, digs the pore-forming back soon, has a large amount of ponding in the hole, and the concrete fills inconveniently.

Disclosure of Invention

The invention aims to solve the defects in the prior art and provides a method for pouring concrete into pile holes of deep foundation pits of garbage bins and slag bins of environment-friendly power plants.

The invention adopts the following technical scheme:

the method for pouring the pile hole concrete of the deep foundation pit of the garbage bin of the environmental protection power plant comprises the following steps:

the underwater concrete pouring is realized, after the guide pipe is poured, the air hole with the head part provided with the 1m long pipe is inserted into the guide pipe through secondary hole cleaning, the minimum distance between the bottom of the air pipe and the bottom of the guide pipe is 2m, compressed air is sprayed out from the bottom of the air pipe, and for the pile hole with the depth less than 10m, the slag is cleaned through an air suction pump, so that the thickness of the sediment at the bottom of the hole is ensured to be less than or equal to 50 mm.

The concrete adopts C30 commercial concrete, the concrete slump is 180-.

The filling conduit is checked for its roundness, verticality and connection tightness, and the conduit is periodically subjected to a water seal test.

The bottom of the conduit in the lower inlet was 300-500mm from the bottom of the well and recorded.

The water-proof plug is a rubber ball matched with the caliber of the conduit. Ensuring enough initial irrigation quantity, ensuring the buried depth to be 0.8-1.5m, and ensuring the buried depth to be 2-6m during continuous irrigation, wherein the irrigation is continuously carried out.

A specially assigned person is sent to measure the embedding depth of the catheter and well records the embedding depth. In the process of pouring concrete, the rising height of the concrete surface needs to be frequently detected, and the depth of the buried pipe needs to be checked. When the concrete rises to the skeleton end opening more than 4m, promote the pipe again, make the pipe end opening be higher than steel reinforcement cage skeleton bottom more than 2m, can resume the speed of pouring, keep normal buried pipe degree of depth, when the filling is close to the pile bolck, will keep sufficient pipe height, adopt measures such as access short pipe, pile body concrete height of over pouring is no less than 1.0m, after chisel out the pile bolck and become slurry, the concrete strength value of guaranteeing pile bolck design elevation height reaches the design requirement.

If the accumulated water in the hole is deep, and when a stratum crack develops, the design elevation of the pile top at the high position of the pouring surface is also required to be determined by the design, the owner, the supervision and the construction field together so as to clear the laitance and ensure the quality of the concrete pile body. And measuring the elevation of the concrete surface before the guide pipe is detached so as to ensure that the poured concrete reaches the designed elevation.

The lifting of the guide pipe should be kept in the middle, the hanging and the collision of the guide pipe with the steel reinforcement cage are prevented, and the detached guide pipe is washed clean in time.

The filling coefficient is measured once every 4m of concrete is poured, the filling coefficient is not less than 1.15, the filling coefficient is not less than 1.18 when the concrete is poured into the whole pile, the concrete filling coefficient is determined according to the site test pile, and the excessive concrete engineering quantity is approved by the Party A and the proctoring visa.

When the funnel is close to the pile top, the height of the funnel is increased by applying a 25t truck crane because the height of concrete in the guide pipe is reduced and the pressure is reduced, so that the pouring is difficult.

When the concrete pouring is finished, the protective cylinder is pulled out at test time, and the opening is well protected, so that accidents are prevented.

When the underwater concrete is poured, the concrete test pieces are kept according to the design and standard requirements, and the 28d strength is measured.

And (3) concrete curing, watering and curing for 2-4 times per day according to weather conditions to keep the surface of the concrete moist, wherein the influence is not less than 14 days, and covering the pile top by using a straw mat.

The invention has the beneficial effects that:

(1) the underwater concrete pouring method can control the speed of concrete flowing out from the bottom end of the pipe, so that the concrete is slowly distributed to the periphery in an expanding way, and cannot be disturbed by the peripheral water flow, thereby ensuring the quality.

(2) And (3) underwater concrete pouring, after the guide pipe is poured, secondary hole cleaning is carried out, the air pipe with the head provided with the long pipe of 1m is inserted into the guide pipe, the minimum distance between the bottom of the air pipe and the bottom of the guide pipe is 2m, compressed air is sprayed out from the bottom of the air pipe, the bottom of the guide pipe can continuously move at the bottom of the pile hole, and sediments can be completely discharged.

(3) By checking the depth of the buried pipe, when the concrete pouring reaches a specified elevation, the pouring speed can be quickly recovered by lifting the height of the guide pipe through simple operation, and the construction period can be optimized.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention are described below clearly and completely, and it is obvious that the described embodiments are some, not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Examples

The comprehensive main power house of the project of the Chengdu's Xingxing environmental protection power plant (second phase) is a combined power house and is caused by a garbage receiving and storing power house, an incineration power house, a flue gas purification power house, a main control building, a waste heat power generation power house, a chimney and the like; the structural form is a reinforced concrete frame bent structure and a steel structure net rack form. The garbage bin is a part of a garbage receiving and storing factory building, and the slag bin is a part of an incineration factory building.

The width of the bottom plate of the garbage bin is 44.85m, the length of the bottom plate of the garbage bin is 146.10m, the top elevation of the bottom plate of the garbage bin is-7.80 m, the bottom elevation of the bottom plate is-9.30 m, the top elevation of the bottom plate of the percolate collecting pool is-9.50 m, the bottom elevation of the bottom plate is-11.00 m, and the thickness of the cushion layer is 100mm, so that the excavation depth of the foundation pit is-11.10 m and-9.40 m.

(1) And (4) according to the geological survey report, the construction range of the project garbage bin foundation pit supporting pile does not show that underground water flows out, so that a hole is formed by rotary drilling in a dry operation mode.

(2) Before construction, pilot drilling is carried out according to a construction scheme to form holes, and a large number of drilling and digging can be started after pilot drilling is successful.

(3) When the drilling machine is in place, the drill rod is required to be kept vertical and stable and accurate in position, and the adjustment and calibration are required to be checked at any time during construction, so that the pile diameter is prevented from being enlarged due to shaking of the drill rod.

(4) After the drilling machine is in place, drill bits with the same size are selected according to the designed pile diameter, a barrel drill is selected for drilling during drilling, the drill bits need to be replaced by tooth drills for drilling when entering a harder rock stratum, and when the drill bits enter middle weathered mudstone or sandstone, the tooth drill with the size smaller than the pile diameter is adopted to drill and dig the rock in the middle of the hole firstly and then drill and dig the rock with the barrel drill with the same diameter.

(5) And (4) constructing according to the parameters determined by the trial hole forming, and setting a full-time recorder to record all parameters of the hole forming process, wherein the record is timely, accurate, complete and real.

(6) The drilling speed is controlled according to the geological condition in the drilling process.

(7) The distance between the two adjacent piles for forming the hole is less than or equal to 3m, a jump digging mode is adopted, the minimum distance between the slag poured out by the drill bit and the pile hole opening is more than 6m, the slag is timely removed for outward transportation, and an excavator is adopted for matching.

(8) In the drilling process, accumulated soil at an orifice is cleaned at any time, and when the abnormal conditions such as underground water, hole collapse, shrinkage and the like happen and the deviation of a geological survey report is large, the geological survey, the design, the construction, the supervision and the like are notified in time to negotiate and determine the treatment.

(9) And (4) checking the position of the pile foundation bearing stratum according to a geological survey report before final hole, and timely clearing holes when the design depth is reached and the pile end bearing stratum and the rock entry depth are satisfied for hr. During hole cleaning, a tooth drill bit which is one type smaller than the pile diameter is adopted for positive and negative circulation cleaning, sediment is cleaned in the drill bit, and the drill bit is lifted to pour out sediment soil.

(10) After the hole is formed to the designed depth, the hole opening is protected and the record is made; the easy-to-collapse hole is provided with a steel casing, the embedding depth is determined according to geological conditions and is generally 2-4 m, and the height is 0.3m higher than the ground.

(11) The allowable deviation of the rotary digging cast-in-place pile hole forming construction should meet the relevant regulations of 'construction foundation and foundation engineering construction quality acceptance standard' GB 50202-2018.

(12) The deviation of the pile diameter is not less than the designed pile diameter, the length of the pile body is not less than the designed pile body length, the allowable deviation of the verticality is 1%, and the allowable deviation of the pile position is less than or equal to 100 mm.

The project garbage bin foundation pit supporting pile adopts a dry operation pore-forming guide pipe underwater concrete pouring method, after a steel reinforcement cage is installed, pile bottom sediment is measured again by a measuring rope, if the sediment thickness exceeds the standard, the steel reinforcement cage is hoisted out, holes are cleaned again by machinery, and whether the pile hole forming quality meets the design and standard requirements is detected again. When this construction work is performed, all the construction machines in the construction site must stop the construction work. And after hole cleaning, the sediment at the bottom of the hole is not more than 50 mm.

(1) Before the steel bar is lofted, the drawing and the specification are familiar carefully, and the steel bar anchoring mode and the length of the node are clarified. The processing and manufacturing size of the steel bar meets the requirement.

(2) The variety, steel number and size specification of the steel bar meet the design requirements, and the manufacturing deviation meets the relevant regulations.

(3) Reinforcement cage welding requirements

1) The steel reinforcement cage of segmentation preparation, the steel bar is lengthened and is adopted single lap welding, and the welding seam is long 10d, and the closure hoop adopts unilateral lap welding with the stirrup of putting more energy into, and the welding seam is long 10d, and the joint should stagger when the main muscle welds, and the steel bar joint number in same cross-section is less than 50% of the total number of main muscle, and the spiral stirrup is with the main muscle spot welding, increases the intensity of steel reinforcement cage. The distance between two adjacent joints is more than 35d and not less than 500 mm.

2) When the connector is welded, the upper main rib and the lower main rib are aligned, and the upper axis and the lower axis of the reinforcement cage are kept consistent.

(4) Arrangement number and mode of sounding pipes

1) And the integrity of the pile body is detected by adopting an ultrasonic transmission method to carry out total detection.

2) 3 acoustic pipes (phi 57 multiplied by 1.5 steel pipes) are pre-buried in each pile to be tested and are uniformly arranged along the inner side of the steel reinforcement cage. Two ends are plugged, the elevation is 200mm higher than the pile top, and the middle is connected by clamping pressure.

(5) Transportation and positioning of reinforcement cage

1) The reinforcement cage adopts the flatbed to carry out horizontal transportation.

2) When the length of the steel reinforcement cage is larger than 12m, the pile hole position is adopted for lengthening, and after the whole steel reinforcement cage is manufactured and accepted, a 25t truck crane is adopted for hoisting in place.

(6) Reinforcement cage protective layer requirements

1) Before the steel reinforcement cage enters the hole, soil and sundries on the steel reinforcement cage are removed, deformed or displaced stirrups are repaired, welded spots which are welded are rewelded or bound, and dirt on the surface of the welded parts is removed in advance.

2) Before the steel reinforcement cage enters the hole, the hole cleaning is completed, the actual hole depth is measured, the actual length of the steel reinforcement cage is determined according to the hole depth and the pile top elevation, and the length of the steel reinforcement cage cannot be smaller than the designed length.

3) When the reinforcement cage is inserted into the hole, the reinforcement cage is lightly placed in the hole and slowly inserted into the hole, and the reinforcement cage is slowly placed after being inserted into the hole, cannot rotate left and right, and is strictly forbidden to be forcibly placed by high-lift and violent falling.

4) After the steel reinforcement cage is lowered and is downthehole to meet the requirements, can with the main reinforcement spot welding on the drill way protects a section of thick bamboo or firmly ligature in the drill way with the iron wire to make the steel reinforcement cage location and prevent the drunkenness.

Because project rubbish storehouse foundation pit excavation depth is darker, and this place of stage is also the lowest-lying section at present moreover, and the stake hole depth is darker, digs the pore-forming back soon, has a large amount of ponding in the hole, and the concrete is filled and then is adopted the concrete filling mode under water, guarantees the concrete filling quality.

The method specifically comprises the following steps:

before the conduit is filled, watertight, pressure-bearing and joint tensile tests are carried out, so that the conduit is straight, airtight and watertight and has sufficient strength and rigidity, and the diameter of the conduit is 300 mm. Short steel bar inclined struts are welded between the pipe wall of the guide pipe and the flanges, so that the steel bar cage is prevented from being pulled up due to the fact that the guide pipe clamps the steel bar cage. And (4) detecting the thickness of the sediment at the bottom of the hole again before pouring, and if the sediment does not meet the design requirement, cleaning the bottom by using high-pressure water so as to ensure that the sediment meets the design requirement. The distance between the lower opening of the guide pipe and the bottom of the hole is kept about 0.25-0.4 m.

The underwater concrete is poured by a conduit method. The concrete slowly flows out from the bottom end of the pipe and is distributed to the periphery in an expanding way, so that the concrete is not disturbed by the surrounding water flow, and the quality is ensured. When the method is adopted, the concrete has good workability, the sand content is between 40 and 50 percent, pebbles with the thickness of not more than 3.8cm are preferably used as coarse aggregates, the water-cement ratio is controlled to be about 0.44, and additives such as retarding, plasticizing and the like can be mixed into the concrete.

The concrete adopts C30 commercial concrete, the concrete slump is 180-.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The method for pouring the pile hole concrete of the deep foundation pit of the garbage bin of the environmental protection power plant comprises the following steps:

step 1, planning underwater pouring concrete, after a pouring guide pipe is placed, secondarily cleaning holes, inserting air holes with 1m long pipes at the head into the guide pipe, enabling the minimum distance between the bottom of an air pipe and the bottom of the guide pipe to be 2m, spraying compressed air from the bottom of the air pipe, cleaning residues of pile holes with the depth of less than 10m by using an air suction pump, ensuring that the thickness of the residues at the bottom of the holes is less than or equal to 50mm, adopting C30 commercial concrete for the concrete, enabling the concrete slump to be 180-fold and 220mm, and performing concrete pouring on support piles by using an arm support pump;

step 2, in the process of pouring concrete, frequently detecting the rising height of the surface of the concrete, checking the depth of a buried pipe, lifting a guide pipe when the concrete rises to a bottom opening of a framework by more than 4m, enabling the bottom opening of the guide pipe to be higher than the bottom of the reinforcement cage by more than 2m, recovering the pouring speed, keeping the normal depth of the buried pipe, keeping enough height of the guide pipe when the concrete is close to the top of a pile, adopting a measure of connecting a short guide pipe, ensuring that the concrete over-pouring height of a pile body is not less than 1.0m, and ensuring that the concrete strength value at the designed height of the top of the pile reaches the design requirement after the pile top is dug out to be grouted;

if the accumulated water in the hole is deep, and the stratum fracture develops, the elevation of the concrete surface is measured before the guide pipe is detached so as to ensure that the poured concrete reaches the designed elevation;

step 3, when approaching the pile top, because the height of the concrete in the guide pipe is reduced, the pressure is reduced, and the pouring is difficult, the height of the funnel is increased by applying a 25t truck crane;

and 4, when the concrete pouring is finished, pulling out the protective cylinder at the test time, and well protecting the orifice to prevent accidents.

2. The method for pouring the concrete into the pile hole of the deep foundation pit of the garbage bin of the environmental protection power plant as claimed in claim 1, wherein in the step 1, the filled conduit is checked for roundness, verticality and connection sealing performance, and a water seal test is performed on the conduit according to time.

3. The method for pouring the concrete into the pile hole of the deep foundation pit of the garbage bin of the environmental protection power plant as claimed in claim 1, wherein in the step 1, the bottom of the conduit in the lower hole is 300-500mm away from the bottom of the hole, and the record is made.

4. The method for pouring the concrete into the pile hole of the deep foundation pit of the garbage bin of the environmental protection power plant according to the claim 1, wherein the step 1 further comprises a rubber ball which is used as a water-proof plug and has the same caliber with the guide pipe, so that the enough initial pouring amount is ensured, the burial depth is 0.8-1.5m, the burial depth is 2-6m during continuous pouring, and the pouring is continuously carried out.

5. The method for pouring the concrete into the pile hole of the deep foundation pit of the garbage bin of the environmental protection power plant according to the claim 1, wherein in the step 2, a specially assigned person is needed to measure the embedding depth of the guide pipe and record the embedding depth.

6. The method for pouring the concrete into the pile hole of the deep foundation pit of the garbage bin of the environmental protection power plant as claimed in claim 1, wherein in the step 2, the lifting of the guide pipe is kept in the middle to prevent the hanging from hitting the reinforcement cage, and the detached guide pipe is washed clean in time.

7. The method for pouring the concrete into the pile hole of the deep foundation pit of the garbage bin of the environmental-friendly power plant according to claim 1, wherein in the step 2, 4m of concrete is poured each time, the filling coefficient is measured, the filling coefficient is not less than 1.15, and the filling coefficient is not less than 1.18 when the concrete is poured into the whole pile.

8. The method for pouring the concrete in the pile hole of the deep foundation pit of the garbage bin of the environmental protection power plant according to the claim 1, wherein after the step 4, when pouring the underwater concrete, the concrete samples are left according to the design and specification required quantity, and the 28d strength is measured.

9. The method for pouring concrete into the pile hole of the deep foundation pit of the garbage bin of the environmental protection power plant as claimed in claim 1, wherein after the step 4, the concrete is cured, and the concrete is watered and cured 2-4 times per day according to weather conditions, so as to keep the surface of the concrete wet, wherein the influence is not less than 14 days, and the pile top is covered by a straw mat.