阅读说明：本技术 一种钻孔灌注桩防腐保护层同步形成方法 (Synchronous forming method for anticorrosive protection layer of cast-in-situ bored pile ) 是由 贾富贵 黄杰 井浩 范奔奔 范颖颖 尹萍 于 2021-09-14 设计创作，主要内容包括：本发明属于建筑桩基技术领域,具体涉及一种钻孔灌注桩防腐保护层同步形成方法,解决了目前盐渍土等地区桩基无有效防腐措施的问题,包括以下步骤：进行常规的钻孔灌注桩成孔工作；准备防腐保护层浆材：在准备灌注水下混凝土时,配制好防腐保护层浆材；下放环形注浆器：在下放钢筋笼的同时,通过提升设备将环形注浆器下放至孔底；提升注浆阶段：在灌注水下混凝土灌注完成后,立即进行提升注浆,边振动提升,边注浆,直至灌注至桩顶,桩身混凝土及防腐保护层同期养生；桩身防腐保护层既有效的提高桩基的抗腐蚀性,又提高桩基承载力,提高混凝土的耐久性,延长桥梁使用寿命。本发明具有原理简单、高效快捷、防腐效果显著等优点。(The invention belongs to the technical field of building pile foundations, and particularly relates to a method for synchronously forming an anticorrosive protection layer of a cast-in-situ bored pile, which solves the problem that the pile foundation in the areas such as saline soil and the like at present has no effective anticorrosive measures and comprises the following steps: performing conventional hole-forming work of the cast-in-situ bored pile; preparing an anticorrosive protective layer slurry material: preparing an anticorrosive protective layer slurry material when underwater concrete is to be poured; and (3) lowering an annular grouting device: lowering the annular grouting device to the bottom of the hole through lifting equipment while lowering the reinforcement cage; and (3) lifting grouting stage: after the underwater concrete is poured, lifting and grouting are immediately carried out, vibration lifting and grouting are carried out simultaneously until the underwater concrete is poured to the pile top, and the pile body concrete and the anticorrosive protective layer are synchronously maintained; the pile body anticorrosion protective layer effectively improves the corrosion resistance of the pile foundation, improves the bearing capacity of the pile foundation, improves the durability of concrete and prolongs the service life of the bridge. The invention has the advantages of simple principle, high efficiency, rapidness, obvious anticorrosion effect and the like.)

1. A synchronous forming method of an anticorrosive protection layer of a cast-in-situ bored pile is characterized by comprising the following steps: the method comprises the following steps:

step 1, pore-forming work: forming a hole by using a cast-in-situ bored pile;

step 2, lowering the annular grouting device: after the hole is formed, an annular grouting device connected with a grouting pipe and a lifting rod is lowered to the bottom of the hole while a reinforcement cage is lowered;

step 3, pretreatment: pressing and injecting an anti-corrosion slurry material to the bottom of the hole through an annular grouting device, and sealing the bottom of the hole;

step 4, lifting grouting stage: after the underwater concrete pouring is finished, lifting and grouting are immediately carried out through lifting equipment and a lifting rod; the lifting process is realized by the aid of lifting equipment in a vibrating mode, grouting is carried out through the grouting pipe, and an annular anticorrosive protective layer is formed after grouting of the annular grouting device.

2. The method for synchronously forming the anticorrosive protection layer of the cast-in-situ bored pile according to claim 1, wherein: before the step 2 is carried out, checking whether the grouting channel is unobstructed by pre-pressing a grouting material into the annular grouting device, and if the grouting channel is blocked, replacing the blocked part.

3. The method for synchronously forming the cast-in-situ bored pile anticorrosion protective layer according to claim 1 or 2, characterized in that: in the step 3, the pressure injection height of the anticorrosive grout is 0.3-0.5 m.

4. The method for synchronously forming the anticorrosive protection layer of the cast-in-situ bored pile according to claim 3, wherein: in step 4, adding a retarder into the concrete to prolong the initial setting time of the concrete; and finishing the pressure injection work of the anti-corrosion protective layer before the pile body concrete does not reach initial setting.

5. The method for synchronously forming the cast-in-situ bored pile anticorrosion protective layer according to claim 1, 2 or 4, wherein: in step 4, the grouting pressure of the grouting pipe is 0.3MPa-0.6MPa, the lifting speed is 0.5mm/min-1.0m/min, and the grouting amount is 15000-30000 ml/min.

6. The method for synchronously forming the anticorrosive protection layer of the cast-in-situ bored pile according to claim 5, wherein: the anti-corrosion mortar material is polymer cement mortar.

7. The method for synchronously forming the anticorrosive protection layer of the cast-in-situ bored pile according to claim 6, wherein: the polymer cement slurry comprises the following components in percentage by weight: cement: water: polymer 0.5-2:0.2-0.5: 0.1-0.6.

8. The method for synchronously forming the anticorrosive protection layer of the cast-in-situ bored pile according to claim 1, wherein: the thickness of the anticorrosion protective layer formed after the annular slip casting device is used for slip casting is not less than 1 cm.

9. The utility model provides a synchronous former of drilling bored concrete pile anticorrosive protection layer which characterized in that: the method for synchronously forming the corrosion protection layer of the cast-in-situ bored pile according to any one of claims 1, 2, 4, 6, 7 and 8 comprises an annular grouting device, a lifting rod, a grouting pipe and a spray head; the upper end of the grouting pipe is connected with a grouting machine through a grout conveying pipe, and the lower end of the grouting pipe is fixedly connected with the annular grouting device and is communicated with an annular pipe arranged in the annular grouting device; a plurality of spray heads are arranged on the circumference of the bottom of the annular pipe, the spray heads are communicated with the inside of the annular pipe, and a slurry outlet is formed in the bottom of the annular slurry injector; the lifting rod is connected with the annular grouting device and used for lifting the annular grouting device.

10. The cast-in-situ bored pile anticorrosion protection layer synchronous forming equipment as claimed in claim 9, wherein: the lifting rod is connected with a lifting device with a vibration function, and the lifting device drives the lifting rod to vibrate while lifting.

11. The cast-in-situ bored pile anticorrosion protection layer synchronous forming equipment as claimed in claim 9, wherein: the inner diameter of the annular grouting device is larger than or equal to the designed diameter of the cast-in-place pile, and the outer diameter of the annular grouting device is smaller than or equal to the diameter of the drilled hole.

12. The cast-in-situ bored pile anticorrosion protection layer synchronous forming equipment as claimed in claim 9, wherein: annular baffles are arranged inside the annular grouting device in a staggered mode at intervals.

Technical Field

The invention belongs to the technical field of building pile foundations, and particularly relates to a synchronous forming method of an anticorrosive protection layer of a cast-in-situ bored pile.

Background

The cast-in-situ bored pile is a pile foundation made by mechanically drilling a pile hole in foundation soil, placing a reinforcement cage in the pile hole and pouring concrete, and is widely applied to building engineering, road and bridge engineering and municipal engineering. Along with the massive construction of high-grade roads in China, higher and higher requirements are put forward on the safety and durability of bridges. In regions with distribution of saline soil such as Qinghai, Liaoning and coastal areas, SO exists in water and soil₄ ^2-、Mg²⁺、Cl^-And the harmful particles can corrode the pile foundation concrete, and the service life of the bridge pile foundation is greatly influenced under the low-temperature climate and freeze-thaw action. Therefore, the improvement of the corrosion resistance of the pile foundation is an important guarantee for meeting the requirements of the safety and the durability of the bridge.

At present, the research on corrosion resistance of pile foundations at home and abroad mainly focuses on the research on corrosion resistance of pile body concrete, and the corrosion resistance of the pile foundations is improved mainly by adding additives. The method is mainly characterized in that the pile foundation is buried in the soil, and structures such as piers and the like which are exposed can not be coated with an anticorrosive layer on the surface, so that the process measures of pile foundation anticorrosion are difficult to realize, and the corrosion resistance and durability of the pile foundation are always the key points and difficulties in highway bridge research. The latest technology at present is that a cloth bag pile construction technology is used for pile foundation corrosion prevention, but the technology is complex, and a pile side cloth bag has great loss of pile side frictional resistance and great influence on pile foundation bearing capacity, so that the cloth bag pile construction technology is not applied in a large range after test.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provides a method for synchronously forming an anticorrosive protective layer of a cast-in-situ bored pile, and solves the problem that the pile foundation in the regions such as saline soil and the like has no effective anticorrosive measures at present.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a synchronous forming method of an anticorrosive protection layer of a cast-in-situ bored pile comprises the following steps:

step 1, pore-forming work: forming a hole by using a cast-in-situ bored pile;

step 2, lowering the annular grouting device: after the hole is formed, an annular grouting device connected with a grouting pipe and a lifting rod is lowered to the bottom of the hole while a reinforcement cage is lowered;

step 3, pretreatment: pressing and injecting an anti-corrosion slurry material to the bottom of the hole through an annular grouting device, and sealing the bottom of the hole;

step 4, lifting grouting stage: after the underwater concrete pouring is finished, lifting and grouting are immediately carried out through lifting equipment and a lifting rod; promote the in-process through the lifting means while vibration promotion, through slip casting pipe limit slip casting, the vibration is favorable to promoting annular slip casting ware, plays closely knit effect to pile body concrete simultaneously, form annular anticorrosive protective layer behind the annular slip casting ware slip casting. The pile body concrete and the anti-corrosion protective layer are maintained at the same time, the anti-corrosion performance of the pile foundation is effectively improved through the pile body anti-corrosion protective layer, the bearing capacity of the pile foundation is improved, the durability of the concrete is improved, and the service life of the bridge is prolonged.

Further, in the step 1, the hole forming work of the cast-in-situ bored pile adopts a conventional technology.

Further, before step 2, through to the annular slip casting ware in the pre-compaction thick liquid material check slip casting passageway unobstructed, if there is the jam, removable has the part that blocks up, used thick liquid material can check whether unobstructed of slip casting passageway can.

Further, in the step 3, the injection height of the anti-corrosion slurry is 0.3m-0.5 m.

Further, in step 4, a retarder is added into the concrete to prolong the initial setting time of the concrete; and (3) completing the pressure grouting work of the anti-corrosion protective layer before the pile body concrete has not reached initial setting, and grouting according to certain grouting pressure, grouting amount and lifting speed until the pile top to form a complete pile body protective layer. Preferably, the grouting pressure of the grouting pipe is 0.3MPa-0.6MPa, the lifting speed is 0.5mm/min-1.0m/min, the grouting amount is 15000-30000ml/min, and the grouting pressure, the grouting amount and the lifting speed can be adjusted according to the length and the diameter of the pile.

Further, selecting a proper annular grouting device according to the design diameter of the cast-in-place pile, wherein the inner diameter of the annular grouting device is larger than or equal to the design diameter of the cast-in-place pile, and the outer diameter of the annular grouting device is smaller than or equal to the diameter of the drilled hole; and the thickness of the anticorrosive protective layer formed after the annular slip casting device 5 performs slip casting is not less than 1 cm.

Further, the anti-corrosion mortar material is polymer cement paste, and preferably, the polymer cement paste comprises the following components in percentage by weight: cement: water: polymer 0.5-2:0.2-0.5: 0.1-0.6. Preferably, the polymer is an acrylate emulsion.

Further, the preparation of the anti-corrosion slurry material adopts a slurry material stirring machine to carry out on-site stirring, and the stirring process is as follows: pre-stirring for 2 minutes, standing for 2 minutes, and stirring for 2 minutes again so as to fully stir and ensure that the stirring is more uniform; the stirring amount is determined according to the grouting speed, and the stirred slurry needs to be used up within 1 hour. During construction, proper amount of water may be added depending on the environmental temperature, wind power and other factors, and the mixture is mixed in standard proportion to obtain the required consistency (the standard proportion refers to the ratio of water to cement being 1: 0.35).

Furthermore, the lifting rod is connected with a lifting device with a vibration function, under the driving of the lifting device, the lifting and the vibration compaction are facilitated, and a continuous and seamless annular anti-corrosion protective layer can be formed after the annular grouting device is grouted.

Compared with the prior art, the invention has the following advantages: the invention has the advantages of simple principle, high efficiency, rapidness, obvious anticorrosion effect and the like, provides a concept of synchronous formation of an anticorrosion protective layer of the cast-in-place pile, opens up a new path of a pile foundation anticorrosion technology, breaks through on the process, and solves two defects of high construction difficulty and influence on bearing capacity in the prior art. The invention can form a complete and reliable anti-corrosion protective layer around the pile of the cast-in-situ bored pile, the anti-corrosion protective layer and the pile body concrete are synchronously applied, and the anti-corrosion protective layer can be well bonded with the pile body and the pile side soil, so that the bearing capacity of the pile foundation is well improved while the anti-corrosion effect is achieved. Because of the vibration effect during the annular grouting, the compactness of the pile body concrete is improved, and the corrosion resistance of the pile body concrete is further improved. The technology is suitable for cast-in-place pile engineering of highway and railway bridges, cast-in-place pile engineering of port engineering, cast-in-place pile engineering of airport engineering, cast-in-place pile engineering of hydraulic engineering, cast-in-place pile engineering of civil engineering and the like in salinized soil areas or under corrosive environments such as seawater and the like, and has wide application and strong adaptability.

Drawings

FIG. 1 is a schematic diagram of the overall structure of the present invention;

FIG. 2 is a transverse cross-sectional view of the annular grouting device of the invention;

FIG. 3 is a longitudinal cross-sectional view of the annular grouter of the present invention.

In the figure, a spray head 1, an annular pipe 2, an outer wall 3, a lifting rod 4, an annular grouting device 5, an inner wall 6, a grouting pipe 7, a grouting machine 8, a slurry conveying pipe 9, a lifting device 10, a slurry outlet 11 and an annular partition plate 12.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings of the specification.

Example 1:

the method for synchronously forming the anticorrosive protection layer of the cast-in-situ bored pile comprises the following steps of:

a. and (3) hole forming work: and carrying out conventional hole-forming work of the cast-in-situ bored pile.

b. Determining the specification of the annular grouting device 5: the annular grouting device 5 with a proper size is selected according to the designed diameter of the cast-in-place pile, the inner diameter of the annular grouting device 5 is required to be larger than or equal to the designed diameter of the cast-in-place pile, the outer diameter of the annular grouting device 5 is required to be smaller than or equal to the diameter of a drilled hole, and the thickness of an anti-corrosion protection layer formed after the annular grouting device 5 is grouted is required to be not smaller than 1 cm.

c. Checking whether the component connection and the grouting channel are unobstructed: checking whether the grouting machine 8 is tightly connected with the grouting pipe 7, the grouting pipe 7 is tightly connected with the annular grouting device 5, and the lifting rod 4 is tightly connected with the annular grouting device 5; whether the grouting channel is unobstructed is checked by prepressing a certain amount of grouting materials, and if the grouting channel is blocked, the blocked part can be replaced.

d. Preparing an anticorrosive protective layer slurry material: when underwater concrete is to be poured, the slurry material of the anticorrosion protective layer is prepared, the stirring needs to be carried out on-site stirring by a slurry material stirrer, the stirring time is prolonged by 2-3 minutes compared with that of the common slurry material, the pre-stirring is carried out for 2 minutes, the standing is carried out for 2 minutes, and the secondary stirring is carried out for 2 minutes so as to be fully and uniformly stirred. The stirring is avoided too much at one time, the stirring is carried out according to the grouting speed, and the stirred slurry materials are used up within 1 hour; in the construction, proper amount of water can be added due to the influence of factors such as environmental temperature, wind power and the like, and the thickness of the mixture is based on the thickness of the mixture mixed in a standard proportion.

e. And (3) lowering an annular grouting device 5: after hole forming, lowering the annular grouting device 5, and lowering the annular grouting device 5 to the bottom of the hole through the lifting equipment 10 while lowering the reinforcement cage; before pouring underwater concrete, firstly pressing and pouring a certain amount of anti-corrosion slurry to seal the bottom of the hole; the lifting device 10 has a vibration function, which is helpful for lifting and vibrating compaction; the annular slip casting device 5 can form a continuous and seamless annular anticorrosion protective layer after slip casting; the annular slip casting device 5 is connected with a slip casting pipe 7 and a lifting rod 4.

f. And (3) lifting grouting stage: after the underwater concrete pouring is finished, lifting and grouting are immediately carried out; the concrete to be poured must be added with a retarder to prolong the initial setting time of the concrete; completing the pressure injection work of the anti-corrosion protective layer before the pile body concrete has not reached initial setting, and injecting slurry according to certain grouting pressure, grouting amount and lifting speed until the pile top to form a complete pile body protective layer; the annular grouting device 5 is lifted by vibration while grouting, and the vibration is beneficial to the lifting of the annular grouting device and simultaneously plays a role in compacting the concrete of the pile body; the pile body concrete and the anti-corrosion protective layer are maintained at the same time, the anti-corrosion performance of the pile foundation is effectively improved through the pile body anti-corrosion protective layer, the bearing capacity of the pile foundation is improved, the durability of the concrete is improved, and the service life of the bridge is prolonged.

In this embodiment, the anti-corrosion mortar material is polymer cement slurry, and preferably, the polymer cement slurry comprises the following components in parts by weight: cement: water: polymer (acrylate emulsion) ═ 1:0.35: 0.3.

In this embodiment, the grouting pressure of the grouting pipe is 0.3MPa-0.6MPa, the lifting speed is 0.5mm/min-1.0m/min, and the grouting amount is 15000-. The synergistic cooperation of grouting pressure, lifting speed and grouting amount can increase and pile body bonding, better guarantee to form continuous, seamless annular anticorrosive protection layer after the slip casting, change any one of them condition and all can influence with pile body adhesion degree and annular anticorrosive protection layer's continuity.

The invention has the following advantages:

1. the prior technical defect that the corrosion resistance of a pile foundation is improved only by adding an additive into pile body concrete is as follows: the strength of concrete is seriously affected by too large mixing amount of the additive, and the concrete cannot be effectively prevented from corrosion by too small mixing amount of the additive. Compared with the prior art, the invention can form an annular protective layer which is made of high-performance anticorrosive materials, can effectively prevent the corrosion of the pile foundation and does not influence the strength of the pile body concrete.

2. The prior cloth bag pile has the technical defects that: construction difficulty seriously affects pile foundation bearing capacity. Compared with the method, the annular protective layer and the pile body concrete are synchronously applied, the strength is formed, the construction is convenient, and the bearing capacity of the pile foundation is not influenced.

3. The prior art pretreats the mud skin of the pile hole wall, has high realization difficulty and has great influence on the hole wall stability. The invention synchronously forms the annular protective layer on the outer side of the pile body concrete, does not influence the stability of the hole wall, is easy to realize and has good anticorrosion effect.

Example 2:

the equipment for synchronously forming the anticorrosive protection layer of the cast-in-situ bored pile for implementing the method in embodiment 1 comprises an annular grouting device 5, a lifting rod 4, a grouting pipe 7 and a nozzle 1; the upper end of the grouting pipe 7 is connected with a grouting machine 8 through a grout conveying pipe 9, and the lower end of the grouting pipe is fixedly connected with the annular grouting device 5 and is communicated with an annular pipe 2 arranged in the annular grouting device 5; a plurality of spray heads 1 are arranged on the circumference of the bottom of the annular pipe 2, the spray heads 1 are communicated with the interior of the annular pipe 2, a slurry outlet 11 is formed in the bottom of the annular grouting device 5, and anticorrosive slurry materials are injected into the grouting pipe 7 through a grouting machine 8 and then enter the annular grouting device 5, and the anticorrosive slurry materials are injected into the hole through the spray heads 1; the lifting rod 4 is connected with the annular grouting device 5 and used for lifting the annular grouting device 5.

Preferably, lifting rod 4 is connected with the lifting means 10 that has the vibration function, and at anticorrosive thick liquids filling process, lifting means 10 drives lifting rod 4 and promotes the limit vibration, drives 5 limit slip casting of annular slip casting ware and promotes the limit vibration from this, is favorable to promoting annular slip casting ware 5 on the one hand, and on the other hand can play closely knit effect to pile body concrete, and then has improved the corrosion resistance of pile body concrete. The lifting device 10 with the vibration function adopts the prior art, and the structure of the lifting device 10 is not described in detail in the invention as long as the lifting device 10 capable of realizing the lifting function while vibrating is adopted.

Preferably, the inner diameter of the annular grouting device 5 is larger than or equal to the design diameter of the cast-in-place pile, and the outer diameter of the annular grouting device 5 is smaller than or equal to the diameter of the drilled hole.

Preferably, the thickness of the anticorrosion protective layer formed after the annular slip casting device 5 is used for casting is not less than 1 cm.

As a possible embodiment, the annular grouting device 5 comprises an inner wall 6 and an outer wall 3 which are coaxially arranged, and the grouting pipe 7 or/and the lifting rod 4 connect the inner wall 6 and the outer wall 3 together.

As a possible other implementation mode, the annular grouting device 5 comprises an inner wall 6 and an outer wall 3 which are coaxially arranged, the tops of the inner wall 6 and the outer wall 3 are connected through a cover plate, the cover plate is integrally connected or welded or detachably connected (bolted) with the inner wall 6 and the outer wall 3, and when the cover plate is detachably connected with the inner wall 6 and the outer wall 3, the joint of the cover plate and the inner wall 6 is sealed, so that the anti-corrosion grout is prevented from overflowing from the top. The grouting pipe 7 penetrates through the cover plate and is fixedly connected with the cover plate, and the bottom of the grouting pipe is communicated with the annular pipe 2 and is fixedly connected with the annular pipe; the lifting rod 4 penetrates through the cover plate and is fixedly connected with the cover plate, and the bottom of the lifting rod is fixedly connected with the annular pipe 2. The two embodiments can realize the connection between the annular pipe 2 and the inner wall 6 and the outer wall 3 without adding other connecting pieces, and are favorable for saving materials and cost.

Annular separators 12 are arranged inside the annular grouting device 5 in a staggered mode at intervals, so that the injection time of the anti-corrosion grout material can be prolonged, and the annular grouting device is better matched with poured concrete.

The above embodiments are only specific examples of the present invention, and the protection scope of the present invention includes but is not limited to the product forms and styles of the above embodiments, and any suitable changes or modifications made by those skilled in the art according to the claims of the present invention shall fall within the protection scope of the present invention.