CN107023002A - Down-the-hole impacts churning composite pile pile making method - Google Patents

Abstract

Churning composite pile pile making method is impacted the invention provides a kind of down-the-hole, the down-the-hole impact churning composite pile pile making method comprises the following steps：Step A：First using downhole impacting high-pressure jet grouting pile construction technology formation soil cement stud；Step B:Then core stake is set in the soil cement stud, down-the-hole impact churning composite pile is formed；Wherein, the core stake is bored concrete pile, concrete precast pile or piling bar.The present invention is applied to the general stratum such as cohesive soil, silt, sand, is also applied for the bad grounds such as muck soil, cobble, gravel, erratic boulder, jackstone, artificial sea-filling region；It can be used as the compressive pile in pile foundation or uplift pile, it is also possible to make the support pile in the reinforcement or base pit engineering of composite foundation.

Description

Pile Forming Method of DTH Impact Rotary Grouting Composite Pile

The present invention requires the patent number: 201620969302.4, and the title of the invention is: down-the-hole impact rotary grouting composite pile, the priority of the Chinese patent.

technical field

The invention relates to the field of geotechnical engineering, in particular to a method for forming a down-the-hole impact rotary spraying composite pile.

Background technique

In the field of geotechnical engineering, according to the purpose, piles can be divided into several categories such as compression piles and uplift piles in foundation engineering, support piles and curtain piles in foundation pit support, and rigid reinforcements in composite foundations; According to the construction technology, it can be divided into two categories: cast-in-place piles and prefabricated piles, among which prefabricated piles include concrete prefabricated piles and steel piles. The two types of piles currently used most in the field of pile foundations are bored piles and prestressed concrete pipe piles; the former is applicable to a wide range of strata and has a large bearing capacity, while the latter has controllable quality and high construction efficiency. However, after many years of practical use, both of them have many problems, which are described as follows.

Bored cast-in-situ piles can generally be divided into two types: dry operation and mud retaining wall. The former is suitable for formations above the groundwater level and with good hole wall stability, and the latter is suitable for formations below the groundwater level and with poor hole wall stability. With the improvement of bearing capacity requirements, the depth of piles is continuously increased. Generally, it is necessary to pass through various strata to enter the bedrock, and the practice of mud retaining walls accounts for a large proportion. This hole-forming method can solve the problem of hole wall stability, but it has relatively high requirements on the specific gravity control of the mud material and construction technology. The bottom sediment is too thick and other problems that are not conducive to the quality control of the pile foundation. In order to solve this problem, the post-grouting technology of cast-in-place piles is derived to make up for the insufficient end resistance caused by the sediment at the pile end or to further increase the pile side frictional resistance. But the process is more complicated, the construction period increases accordingly, and the cost also increases greatly.

Concrete prefabricated piles and steel piles are close to the concept of prefabricated assembly. The finished piles prefabricated in the factory and with controllable quality are sunk into the ground through specific equipment on site. The process is simple and the construction is fast. However, this type of pile has higher requirements on the stratum, and the bending stiffness of the pile body is lower than that of cast-in-situ piles, so it is not suitable for areas with high seismic intensity.

Composite piles are a new solution, that is, constructing cement-soil external piles first, and then inserting core piles to form composite piles with external flexibility and internal rigidity. The construction method of the cement-soil external pile is generally the traditional high-pressure rotary spraying or cement mixing. After the pile is formed, the core pile is inserted by sinking, drilling or hammering according to different requirements to form a composite pile. However, due to the relatively limited adaptability of the traditional high-pressure rotary spraying process and cement mixing process to the stratum, it can generally be used in cohesive soil, silt, loose sand and other strata, and cannot be used in dense sand, pebbles, gravels, sandy soils, etc. The miscellaneous filling formations of rocks limit the further promotion and implementation of this kind of technology.

To sum up, the following problems exist in the prior art: the existing composite piles are applicable to a small stratum range, and have weak adaptability to core piles.

Contents of the invention

The invention provides a method for forming a down-the-hole impact rotary grouting composite pile to solve the problems that the existing composite pile is applicable to a small stratum range and has weak adaptability to core piles.

For this reason, the present invention proposes a kind of down-the-hole impact rotary grouting composite pile forming method, described down-the-hole impact rotary grouting composite pile forming method comprises the following steps:

Step A: first use the down-the-hole impact high-pressure rotary grouting pile construction technology to form the cement-soil outer pile;

Step B: then core piles are set in the cement-soil outer piles to form down-the-hole impact rotary grouting composite piles;

Wherein, the core pile is cast-in-place pile, concrete prefabricated pile or steel pile.

Further, the pile bodies of the cement-soil external piles have equal diameters or unequal diameters.

Further, the step A includes expanding the diameter or bottom of the cement-soil external pile.

Further, the cast-in-situ piles include: cast-in-place piles with immersed tubes, internally rammed cast-in-place piles, auger-drilled cast-in-situ piles and threaded cast-in-place piles.

Further, the core pile is an auger drilled grouting pile, and the step B includes: using an auger drill to form a hole, and after reaching the design depth, pouring concrete in the center of the hole, and inserting a steel cage in reverse to form a pile.

Further, the core pile is a cast-in-situ pile, and the step B includes: forming a hole by hammering, vibrating and other sinking methods, preferably using a prefabricated pile tip, inserting a steel cage and pouring concrete to form a pile.

Further, the core pile is an internally rammed cast-in-place pile, and the step B includes: using an internally rammed drilling rig casing to follow up and impact to form a hole, while impacting to form a hole, the cement-soil outer pile is compacted, and the pile end The expansion head is internally rammed, the steel cage is lowered, the core pile concrete is poured, and the casing is lifted to form a pile.

Further, the core pile is a threaded cast-in-place pile, and the step B includes: using a threaded pile machine to form a hole, while forming a hole with a threaded drill rod, and relying on the extrusion of the thread to produce a compacting effect on the cement-soil outer pile.

Further, the core pile is a concrete prefabricated pile, and the concrete prefabricated pile includes: a concrete solid square pile, a prestressed concrete pipe pile, a prestressed concrete hollow square pile and a prefabricated threaded pile, and the step B includes: using a vibrating hammer Lower prestressed concrete pipe piles, prestressed concrete hollow square piles, or prefabricated threaded piles to the design depth by means of hanging, static pressure, hammering, and rotation.

Further, the core piles are steel piles, and the steel piles include: steel pipe piles, H-shaped steel piles or other special-shaped steel piles, and the step B includes: lifting by vibrating hammer, static pressure, hammering, and turning Lower steel pipe piles, H-shaped steel piles or other special-shaped steel piles to the design depth.

The invention adopts the construction technology and equipment of submerged hole impact high-pressure rotary grouting piles to form cement-soil outer piles, and then adopts different techniques to construct different types of core piles according to actual needs. Through the organic combination and interaction of the cement-soil outer pile and the core pile, the side friction resistance of the core pile and the end resistance of the pile end can be improved; at the same time, the cement-soil outer pile can also increase the ability of the pile to resist horizontal loads and improve the seismic resistance of the pile foundation performance. The pile is suitable for general formations such as cohesive soil, silt, sandy soil, etc., and also for complex formations such as muddy soil, pebbles, gravels, boulders, riprap, and artificial reclamation areas; it can be used as an anti-corrosion pile in pile foundations Pressure piles or uplift piles can also be used as reinforcements for composite foundations or support piles in foundation pit engineering.

Description of drawings

Fig. 1 is the schematic diagram of the working principle of the pile-forming method of the down-the-hole impact rotary grouting composite pile of the present invention, wherein, the core pile is an auger bored pressure-grown pile or a sinking-pipe cast-in-place pile or an internally rammed sinker-pipe cast-in-situ pile;

Fig. 2 is a schematic diagram of the working principle of the pile-forming method of the down-the-hole impact rotary grouting composite pile of the present invention, wherein the core pile is a prestressed concrete pipe pile or a concrete hollow square pile;

Fig. 3 is a schematic diagram of the working principle of the pile-forming method of the down-the-hole impact rotary grouting composite pile of the present invention, wherein the core pile is a threaded cast-in-place pile or a prefabricated screw pile;

Fig. 4 is a structural schematic diagram of expanding the diameter of cement-soil outer piles by the pile-forming method of submerged-hole impact rotary grouting composite piles of the present invention, wherein the core piles are auger-drilled grouting piles or sinking tube grouting piles or internally rammed sinking tube grouting piles ;

Fig. 5 is the structure schematic diagram of expanding the diameter of the cement-soil outer pile by the pile forming method of the down-the-hole impact rotary grouting composite pile of the present invention, wherein, the core pile is a prestressed concrete pipe pile or a concrete hollow square pile;

Fig. 6 is a structural schematic diagram of expanding the diameter of cement-soil outer piles by the pile-forming method of the down-the-hole impact rotary grouting composite pile of the present invention, wherein the core pile is a threaded cast-in-place pile or a prefabricated screw pile.

Explanation of reference numbers:

1-Cement-soil outer pile; 2-Core pile; 5-Cement-soil outer pile diameter expansion; 6-Cement-soil outer pile bottom expansion;

detailed description

In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the present invention will now be described with reference to the accompanying drawings.

The invention discloses a pile-forming method of a submerged-hole impact rotary-grouting composite pile, which comprises the following steps:

Step A: first use the down-the-hole impact high-pressure rotary grouting pile construction technology to form the cement-soil outer pile 1; Spraying, that is, horizontal high-pressure spraying above the bottom of the down-the-hole impactor. While drilling, provide high-pressure water (slurry) with a pressure of not less than 15MPa to the injector to cut and soften the soil to ensure the radial aperture during drilling; In addition to the construction of rotary grouting piles in cohesive soil, silt and loose sand, large diameter rotary grouting piles can also be formed in dense sand layers, pebbles, gravels, and miscellaneous fill formations containing riprap; and the verticality of piles is deviated The control value is less than 1%; the specific construction technology of down-the-hole impact high-pressure rotary grouting pile can refer to the existing mature technology;

Step B: set core pile 2 in described cement-soil outer pile then, form down-the-hole impact rotary grouting compound pile; After described cement-soil outer pile construction is finished, can choose different time to carry out core according to the difference of core pile type Pile construction; the core pile 2 can be cast-in-situ pile, concrete prefabricated pile, steel pile or any other type of pile.

Further, as shown in Fig. 1, Fig. 2 and Fig. 3, the pile bodies of the cement-soil outer pile 1 are equal in diameter, forming a larger and more uniform cement-soil outer pile; as shown in Fig. 4, Fig. 5 and As shown in Fig. 6, the pile bodies of the cement-soil outer pile 1 are unequal diameters, and can also be expanded in diameter or bottom according to design requirements, forming the expanded diameter 5 of the cement-soil outer pile and the enlarged bottom 6 of the cement-soil outer pile.

Further, the cast-in-situ piles include: cast-in-place piles with immersed tubes, internally rammed cast-in-place piles, auger-drilled cast-in-situ piles and threaded cast-in-place piles.

Further, as shown in Figures 1 and 4, the core pile 2 is an auger-drilled grouting pile, and the step B includes: using an auger drill to form a hole, and after the designed depth is reached, concrete is poured in the center of the hole, and then Insert reinforcement cages into piles.

Further, as shown in Fig. 1 and Fig. 4, the core pile 2 is a pipe sinking cast-in-situ pile, and the step B includes: using hammering, vibration and other sinking methods to form holes, preferably using prefabricated pile tips, inserting steel bars Concrete is poured after the cage to form a pile.

Further, as shown in Fig. 1 and Fig. 4, the core pile 2 is an internally rammed cast-in-situ pile, and the step B includes: using an internally rammed drilling rig casing to follow up and impact the hole, and impact the cement while forming the hole. The pile outside the soil produces a compaction effect, the pile end is internally rammed to expand the head, the steel cage is lowered, the core pile concrete is poured, and the casing is lifted to form a pile.

Further, as shown in Fig. 3 and Fig. 6, the core pile 2 is a threaded cast-in-situ pile, and the step B includes: using a threaded pile driver to form a hole, and while the threaded drill rod is forming a hole, relying on the extrusion of the thread, the The cement-soil external pile produces compaction.

Further, as shown in Figure 2 and Figure 5, the core pile 2 is a concrete prefabricated pile, and the concrete prefabricated pile includes: a concrete solid square pile, a prestressed concrete pipe pile, a prestressed concrete hollow square pile and a prefabricated threaded pile , the step B includes: lowering the prestressed concrete pipe pile, the prestressed concrete hollow square pile, or the prefabricated threaded pile to the design depth by means of vibrating hammer lifting, static pressure, hammering, and rotation.

Further, the core piles are steel piles, and the steel piles include: steel pipe piles, H-shaped steel piles or other special-shaped steel piles, and the step B includes: lifting by vibrating hammer, static pressure, hammering, and turning Lower steel pipe piles, H-shaped steel piles or other special-shaped steel piles to the design depth. The construction is carried out after the submerged hole impacts the high-pressure rotary grouting pile to form the cement-soil outer pile; when it is used for the support pile of the foundation pit project or the support curtain integrated pile, the core pile can be pulled out for recycling.

Concrete operating process of the present invention is for example:

(1) Pile position measurement and placement: According to the designed pile position, traditional measuring instruments or high-precision automatic positioning measurement technology are used to measure and locate the pile position.

(2) External pile operation: After the submersible impact rotary jet mixing pile machine is in place, the impactor starts to work. While drilling, provide high-pressure water (slurry) with a pressure of not less than 15MPa to the injector to cut and soften the soil. After the hole is formed to the designed depth, high-pressure cement slurry is sprayed, and the drill bit is lifted and lowered according to the construction needs for repeated rotary spraying to form a larger diameter and more uniform cement-soil external pile.

(3) Core pile operation:

① When the core pile adopts long auger drilling and grouting piles, within a certain period of time after the cement-soil outer pile is formed, the long auger drilling machine is used to form the hole. After the design depth is reached, the concrete is poured in the center, and the steel cage is inserted reversely to form the pile .

② When the core piles are cast-in-place piles, within a certain period of time after the cement-soil outer piles are piled, pipe sinking methods such as hammering and vibration are used to form holes. pile.

③ When the core pile is an internally rammed sinking pipe pouring pile, within a certain period of time after the cement-soil outer pile is formed, the casing of the internal ramming drilling rig is used to follow up and impact the hole. Compacting effect, internally ramming and expanding the pile end, lowering the reinforcement cage, pouring concrete for the core pile, and lifting the casing to form a pile.

④ When the core pile is a threaded cast-in-situ pile, within a certain period of time after the cement soil pile is formed, a threaded pile machine is used to form a hole. While the threaded drill pipe is forming a hole, relying on the extrusion of the thread, the cement soil outer pile is compacted To enhance the pile body strength of the outer pile and the integrity of the core pile and the outer pile.

⑤ When the core pile is a prefabricated pile, the prestressed concrete pipe pile, precast concrete hollow square pile, precast concrete hollow square pile, The prefabricated threaded piles are lowered to the design depth.

⑥When the core pile is a steel pile, within a certain period of time after the cement-soil outer pile is formed, the steel pipe pile, H-shaped steel pile or other special-shaped The steel piles are lowered to the design depth.

The above descriptions are only illustrative specific implementations of the present invention, and are not intended to limit the scope of the present invention. Because the various components of the present invention can be combined with each other under the condition of no conflict, any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall belong to the protection of the present invention. range.

Claims (10)

1. a kind of down-the-hole impacts churning composite pile pile making method, it is characterised in that the down-the-hole impact churning composite pile pile side Method comprises the following steps：

Step A：First using downhole impacting high-pressure jet grouting pile construction technology formation soil cement stud；

Step B:Then core stake is set in the soil cement stud, down-the-hole impact churning composite pile is formed；

Wherein, the core stake is bored concrete pile, concrete precast pile or piling bar.

2. down-the-hole as claimed in claim 1 impacts churning composite pile pile making method, it is characterised in that the soil cement stud Pile body is equal diameter or non-equal diameter.

3. down-the-hole as claimed in claim 1 impacts churning composite pile pile making method, it is characterised in that the step A includes pair Soil cement stud carries out expanding or base expanding and base expanding.

4. down-the-hole as claimed in claim 1 impacts churning composite pile pile making method, it is characterised in that the bored concrete pile includes： Driven cast-in-place pile, interior rammer driven cast-in-place pile, auger boring guncreting pile and screw cast-in-place pile.

5. down-the-hole as claimed in claim 1 impacts churning composite pile pile making method, it is characterised in that the core stake is auger Hole guncreting pile, the step B includes：Using twist bit pore-forming, reach after projected depth, in hole center guncreting, instead Insert steel reinforcement cage pile.

6. down-the-hole as claimed in claim 1 impacts churning composite pile pile making method, it is characterised in that the core stake fills for immersed tube Stake is noted, the step B includes：Pore-forming is carried out using immersed tunnelling methods such as hammering, vibrations, preferably using precast pile tip, after insertion steel reinforcement cage Concrete perfusion pile.

7. down-the-hole as claimed in claim 1 impacts churning composite pile pile making method, it is characterised in that the core stake rams heavy to be interior Pipe perfusion pile, the step B includes：Using interior rammer rig sleeve pipe follow-up impact holing, while impact holing to soil cement outside Stake, which is produced, rams enlarged footing in crowd in-out effects, stake end, transfer steel reinforcement cage, pour core pile concrete, promote sleeve pipe pile.

8. down-the-hole as claimed in claim 1 impacts churning composite pile pile making method, it is characterised in that the core stake fills for screw thread Stake is noted, the step B includes：Using screw-thread pile machine pore-forming, while threaded drillpipe pore-forming, by the extruding of screw thread, to cement Native stud produces crowd in-out effects.

9. down-the-hole as claimed in claim 1 impacts churning composite pile pile making method, it is characterised in that the core stake is concrete Prefabricated pile, the concrete precast pile includes：Concrete solid square pile, prestressed concrete pipe pile, pre-stressed concrete hollow Square pile and pre-threaded stake, the step B include：Hung using vibration hammer, static pressure, hammering, revolution mode is by prestressed concrete Pile tube, pre-stressed concrete hollow square stake or pre-threaded stake are transferred to projected depth.

10. down-the-hole impact churning composite pile pile making method as claimed in claim 1, it is characterised in that the core stake is piling bar, The piling bar includes：Steel-pipe pile, H profile steel stake or other special-shaped piling bars, the step B include：Hung using vibration hammer, static pressure, hammer Hit, revolution mode transfers steel-pipe pile, H profile steel stake or other special-shaped piling bars to projected depth.