CN111962523A - A combined support structure of inclined pipe pile and vertical wedge pile and its construction method - Google Patents

Abstract

The invention discloses a combined support structure of inclined pipe piles and vertical wedge-shaped piles. The inner side is arranged, and a crown beam is arranged on the top of the pipe pile and the wedge-shaped pile; the axis of the wedge-shaped pile is perpendicular to the horizontal plane, and the area of its cross-section decreases from the top of the pile to the bottom of the pile; the The axis of the pipe pile is inclined to the horizontal plane and the lower part thereof is inclined to the foundation pit; the center line of the pile top of the pipe pile is parallel or coincident with the center line of the pile top of the wedge-shaped pile. The invention also discloses a construction method of the combined support structure of the inclined pipe pile and the vertical wedge pile. The invention can reduce the displacement of the pile top, increase the excavation depth, reduce the possibility of overturning and damage of the foundation pit, and can reduce the design strength of the supporting pile to reduce the construction cost.

Description

A combined support structure of inclined pipe pile and vertical wedge pile and its construction method

technical field

The invention relates to a foundation pit support structure and a construction method, in particular to a combined support structure of an inclined pipe pile and a vertical wedge pile and a construction method thereof.

Background technique

At present, with the advancement of the country's urbanization process, underground large-area and long-length foundation pits account for more than 80% of the total area of foundation pits in my country. However, the traditional support method has major deficiencies and defects: 1. For the cantilever foundation pit support structure, it can only be applied to the foundation pit engineering with shallow excavation depth and good soil conditions; Although the inner support structure can be used in deep foundation pits, the construction is complicated, the construction period is long, the environmental pollution is serious, and the cost is high. Therefore, the inclined pile support structure came into being. By inclining the vertical cantilever support piles to the foundation pit at a certain angle, the inclined support piles are formed, and the inclined support piles and the vertical support piles are alternately arranged to form the inclined support piles. Straight alternating support structure. The traditional inclined-straight alternate support piles all use pipe piles. In soft soil foundation engineering, the stress form of pipe piles is mostly friction foundation piles. The specific surface area of the pile body (the ratio of the unit concrete volume to the external surface area of the pile body) is small, so the force between the surface of the pipe pile and the soil is far less than the strength of the pile body, and the structural strength of the pile body cannot be fully exerted, resulting in This results in a great waste of the bearing capacity of the concrete pipe pile, and cannot give full play to the friction force of the pile body of the supporting structure. The overall supporting capacity of the supporting structure is mainly exerted by the pulling force given by the straight piles to the inclined piles, and the traditional pipe piles cannot fully exert this pulling force.

SUMMARY OF THE INVENTION

In order to solve the technical problems existing in the known technology, the present invention provides a combined support structure of inclined pipe piles and vertical wedge piles and a construction method thereof.

The technical scheme adopted by the present invention to solve the technical problems existing in the known technology is: a combined support structure of inclined pipe piles and vertical wedge piles, including a pile row support structure formed by alternately arranging pipe piles and wedge piles ; The pipe pile and the wedge-shaped pile are arranged along the inner side of the edge of the foundation pit, and a crown beam is arranged on the pile top of the pipe pile and the wedge-shaped pile; the axis of the wedge-shaped pile is perpendicular to the horizontal plane, and its cross section is The area of the pipe pile gradually decreases from the top of the pile to the bottom of the pile; the axis of the pipe pile is inclined to the horizontal plane and the lower part of the pipe pile is inclined to the foundation pit; the line connecting the center of the pile top of the pipe pile and the center of the pile top of the wedge-shaped pile parallel or coincident.

Further, the included angle between the axis of the pipe pile and the axis of the wedge-shaped pile is ≤30°.

Further, the depth of the pile bottom of the pipe pile or the wedge-shaped pile is 2-2.5 times the excavation depth of the foundation pit.

Further, the diameter of the pipe pile is 300-600 mm; the diameter of the top of the wedge-shaped pile is 600-1200 mm, and the wedge angle of the wedge-shaped pile is 5°-15°.

Further, the width direction edge of the crown beam exceeds the pile top edge of the pipe pile and the wedge-shaped pile, and the height of the crown beam is greater than or equal to 0.6 times the diameter of the pipe pile or 0.6 times the average pile diameter of the wedge-shaped pile. .

Further, the size of the width direction edge of the crown beam extending beyond the pipe pile and the pile top edge of the wedge pile on one side is: 1/2 the pile diameter of the pipe pile or 1/2 the average pile diameter of the wedge pile.

The invention also provides a method for constructing a combined support structure of inclined pipe piles and vertical wedge piles, the method comprising: prefabricating pipe piles and wedge piles; Pipe piles and wedge-shaped piles are alternately arranged to form a pile-row support structure; the axis of the wedge-shaped piles is perpendicular to the horizontal plane and the area of its cross-section decreases from the top of the pile to the bottom of the pile; the axis of the pipe piles is inclined to the horizontal plane and its lower part faces toward The foundation pit is inclined; the center line of the pile top of the pipe pile and the center line of the pile top of the wedge pile should be parallel or overlapped. Piles; prefabricated crown beams on the pile tops of pipe piles and wedge piles.

Further, the method for laying wedge-shaped piles on site comprises the following steps:

Step A-1, carry out the wedge-shaped pile hole forming operation on the target foundation, so that the digging hole diameter gradually becomes smaller from top to bottom;

Step A-2, after forming the hole, first lay a concrete cushion at the bottom of the hole;

Step A-3, after the wedge-shaped pile is hoisted and lowered, pour concrete into the hollow section, and vibrate and compact while pouring;

Step A-4, after the pouring is completed, excavate the foundation pit of the cap, and align the bolt holes and grouting holes of the cap cover with the fixing bolts and grouting guides of the top section of the wedge pile, so that the cap cover is aligned. Fit with the pile top of the wedge-shaped pile and the side wall of the cap foundation pit, backfill the cap foundation pit, and fill the edge tightly;

Step A-5, grouting the conduit with cement slurry until the soil layer on the side of the pile has cement slurry overflowing.

Further, set the length of the wedge-shaped pile to be L, and set the cement mixing pile water-proof curtain on the outside of the connection line of the pile top center of the wedge-shaped pile and 0.2L from the center connection line of the pile top of the wedge-shaped pile; the construction method of the cement mixing pile water-proof curtain; It includes the following steps:

Step B-1, bring the deep mixer to the designated pile position and center it;

Step B-2, after the cooling water circulation of the deep mixer is normal, start the deep mixer, so that the deep mixer stirs and cuts the soil along the guide frame and sinks;

Step B-3, when the deep mixer sinks to the set depth, stir the cement slurry and pour the cement slurry into the hopper;

Step B-4, when the deep mixer sinks to the design depth, turn on the cement slurry pump to press the cement slurry into the foundation, and rotate and stir while spraying, and at the same time lift the deep mixer according to the lifting speed determined by the design;

Step B-5, after the deep mixer is raised to the top surface elevation of the design depth, the deep mixer is sunk into the soil while rotating and stirring again, and the deep mixer is lifted out of the ground after reaching the design depth.

Further, the method of prefabricating the crown beam on the pile top of the pipe pile and the pile top of the wedge pile includes the following steps:

Step C-1, the crown beam earthwork is excavated by mechanical partitions. First, the first layer of earthwork is excavated to the pile top elevation of the wedge-shaped pile. After removing the remaining soil, the pile head floating slurry is removed to the design elevation. The concrete on the top surface of the pile core should be Chisel hair treatment to remove scum at the top of the pile. If the strength of the pile head concrete at the design elevation fails to meet the design requirements, continue to break until the quality of the concrete meets the design requirements;

Step C-2, the soil between the piles is leveled to the bottom elevation of the crown beam, and compacted by ramming;

In step C-3, steel bars are made according to the section reinforcement of the crown beam; the longitudinal bars are HRB335 grade or HRB400 grade steel bars, the stirrups are HPB300 grade steel bars; the tie bars are HRB335 grade steel bars;

In step C-4, the concrete pouring and curing are completed; the concrete strength grade is higher than or equal to C25, and the main reinforcement of the row pile is anchored into the crown beam larger than or equal to 35 times the diameter of the reinforcement pile.

The advantages and positive effects of the present invention are: a combined support structure of inclined pipe piles and vertical wedge-shaped piles of the present invention, the pipe piles and the wedge-shaped piles are alternately arranged to form an equal-height combined support structure, so that the axis of the wedge-shaped piles is vertical On the horizontal plane and its cross-sectional area decreases from the top of the pile to the bottom of the pile; the axis of the pipe pile is inclined to the horizontal plane and its lower part is inclined to the foundation pit; the wedge-shaped pile can increase the lateral friction resistance, so that the axial force can be fully exerted. Giving the pipe piles greater tensile force can greatly reduce the displacement of the pile top, greatly reduce the ground deformation after the pile is installed, and avoid damage to the surrounding environment. The invention can increase the excavation depth, and because the excavation surface is inclined, the bearing capacity of the wedge-shaped pile is high, and the settlement is small, the possibility of overturning damage of the foundation pit is greatly reduced, and the foundation pit engineering can be guaranteed. Pipe piles and wedge-shaped piles are alternately arranged to form an equal-height composite support structure, so that the foundation pit project that may need to use internal support or anchor support can only be supported by cantilever piles to meet the design requirements. requirements, so as to make the design and construction easier, and save materials, thereby reducing engineering costs.

To sum up, the present invention can reduce the displacement of the pile top, increase the excavation depth, reduce the possibility of overturning and damage of the foundation pit, and can reduce the design strength of the supporting pile to reduce the cost of foundation pit support engineering.

Description of drawings

FIG. 1 is a schematic diagram of a combined support structure of an inclined pipe pile and a vertical wedge pile according to the present invention.

In the picture: 1- crown beam; 2- foundation pit bottom; 3- foundation pit edge; 4- wedge-shaped pile; 5- pipe pile.

2 is a schematic cross-sectional view of a combined support structure of an inclined pipe pile and a vertical wedge pile according to the present invention.

In the figure: H ₁ - excavation depth of foundation pit; H ₂ - length of wedge pile; θ - inclination angle of pipe pile.

Detailed ways

In order to further understand the content of the invention, features and effects of the present invention, the following embodiments are listed herewith, and are described in detail as follows in conjunction with the accompanying drawings:

Please refer to FIGS. 1 to 2 , a combined support structure of inclined pipe piles and vertical wedge-shaped piles, including a pile-row support structure composed of pipe piles 5 and wedge-shaped piles 4 alternately arranged; The wedge-shaped pile 4 is arranged along the inner side of the edge 3 of the foundation pit, and a crown beam 1 is arranged on the pile top of the pipe pile 5 and the pile top of the wedge-shaped pile 4; the wedge-shaped pile 4, its axis is perpendicular to the horizontal plane, The area of its cross section becomes smaller from the top of the pile to the bottom of the pile; the axis of the pipe pile 5 is inclined to the horizontal plane and its lower part is inclined to the foundation pit; the center line of the pile top of the pipe pile 5 and the wedge-shaped pile 4 The lines connecting the center of the pile tops are parallel or coincident. The pile tops of the pipe piles 5 and the wedge-shaped piles 4 are located on the inner side of the edge 3 of the foundation pit, and the pipe piles 5 and the wedge-shaped piles 4 are connected by the crown beam 1 to form a whole.

The center line of the pile top of the pipe pile 5 can be located on the inner side of the center line of the pile top of the wedge-shaped pile 4; Or 2 to 4 times the average pile diameter of wedge piles.

The axis of the wedge-shaped pile is a straight line perpendicular to its top surface and intersecting the center of its top surface. The diameter of the wedge-shaped pile is the ratio of 4 times the area of the cross-section perpendicular to its axis to the perimeter; the area of the cross-section of the wedge-shaped pile is from The pile top to the pile bottom becomes smaller in turn; the corresponding pile diameter also becomes smaller from the pile top to the pile bottom.

The inclination angle of the axis of the pipe pile 5 relative to the axis of the wedge pile 4 may be greater than 0° and less than or equal to 30.5°, and the included angle between the axis of the pipe pile and the axis of the wedge pile is preferably ≤30°. As shown in FIG. 2 , the included angle between the axis of the pipe pile and the axis of the wedge-shaped pile can be referred to as the pipe pile inclination angle θ, and the pipe pile inclination angle θ can be ≤30°. The pipe pile inclination angle θ may preferably be 10°, 12°, 15°, 18°, 21°, 24°.

The depth of the pile bottom of the pipe pile 5 or the wedge pile 4 may be 2 to 2.5 times the excavation depth H ₁ of the foundation pit. That is, the height of the pile bottom end of the pipe pile 5 or the wedge pile 4 from the foundation pit bottom 2 is 2 to 2.5 times the foundation pit excavation depth H ₁ .

The diameter of the pipe pile may be 300-600 mm; the diameter of the pile top of the wedge-shaped pile may be 600-1200 mm, and the wedge angle of the wedge-shaped pile may be 5°-15°. The wedge angle of the wedge pile is preferably 7.5°, 9°, 12°.

Crown beams 1 are arranged on wedge piles 4 and pipe piles 5 . The width of the crown beam 1 can be larger than the pile diameter of the pipe pile 5 and the wedge pile 4 connected to it, and the width direction edge of the crown beam 1 can exceed the pile top edge of the pipe pile 5 and the wedge pile 4, The height of the crown beam 1 may be greater than or equal to 0.6 times the diameter of the pipe pile 5 or 0.6 times the average diameter of the wedge pile 4 .

Further, the size of the width direction edge of the crown beam 1 beyond the pipe pile 5 and the pile top edge of the wedge pile 4 can be: 1/2 the pile diameter of the pipe pile 5 or 1/2 the wedge pile. 4 for the average pile diameter.

The length of the wedge-shaped pile can be set to be L, and the cement mixing pile water-proof curtain can be set at the outer side of the connection line of the pile top center of the wedge-shaped pile and 0.2L away from the connection line of the pile top center of the wedge-shaped pile.

The present invention also provides an embodiment of a method for constructing a combined support structure of inclined pipe piles and vertical wedge-shaped piles. The method includes: prefabricating pipe piles 5 and wedge-shaped piles 4; and wedge-shaped piles 4, so that the pipe piles 5 and wedge-shaped piles 4 are alternately arranged to form a pile-row supporting structure; the axis of the wedge-shaped piles 4 is perpendicular to the horizontal plane and the area of its cross-section decreases from the top of the pile to the bottom of the pile; The axis of 5 is inclined to the horizontal plane and its lower part is inclined to the foundation pit; the center line of the pile top of the pipe pile 5 and the center line of the pile top of the wedge-shaped pile 4 are parallel or coincident, and the pipe pile 5 and the wedge-shaped pile 4 are constructed by jumping piles. Method, 1-2 piles are pressed into the next prefabricated pile; the crown beam 1 is prefabricated on the pile top of the pipe pile 5 and the pile top of the wedge pile 4 . The center line of the pile top of the pipe pile 5 can be located on the inner side of the center line of the pile top of the wedge-shaped pile 4; Pile diameter or 2 to 4 times the average pile diameter of wedge-shaped piles.

Further, the method for laying the wedge-shaped piles 4 on site may include the following steps:

In step A-1, the wedge-shaped pile 4 is drilled on the target foundation, so that the digging hole diameter gradually becomes smaller from top to bottom.

Step A-2, after forming the hole, first lay a concrete cushion at the bottom of the hole.

In step A-3, after the wedge-shaped pile 4 is hoisted and lowered, concrete is poured into the hollow section, and it is vibrated and compacted while pouring.

Step A-4: After the pouring is completed, excavate the foundation pit of the cap, and align the bolt holes and grouting holes of the cap cover with the fixing bolts and grouting guides of the top section of the wedge pile 4 to make the cap cover. The plate is attached to the pile top of the wedge-shaped pile 4 and the side wall of the foundation pit of the cap, backfill the foundation pit of the cap, and fill the edge tightly.

Step A-5, grouting the conduit with cement slurry until the soil layer on the side of the pile has cement slurry overflowing.

Further, the length of the wedge-shaped pile 4 can be set to be L, and the cement mixing pile water-proof curtain can be set at the outer side of the connection line of the pile top center of the wedge-shaped pile 4 and at a distance of 0.2L from the center connection line of the pile top of the wedge-shaped pile 4; The construction method of the water curtain may include the following steps:

Step B-1, bring the deep mixer to the designated pile position and center it.

Step B-2, after the cooling water circulation of the deep mixer is normal, start the deep mixer, so that the deep mixer stirs and cuts the soil along the guide frame and sinks.

Step B-3, when the deep mixer sinks to the set depth, stir the cement slurry and pour the cement slurry into the hopper.

Step B-4, when the deep mixer sinks to the design depth, turn on the cement slurry pump to press the cement slurry into the foundation, and rotate and mix while spraying, and at the same time lift the deep mixer according to the lifting speed determined by the design.

Step B-5, after the deep mixer is raised to the top surface elevation of the design depth, the deep mixer is sunk into the soil while rotating and stirring again, and the deep mixer is lifted out of the ground after reaching the design depth.

Further, the method for prefabricating the crown beam 1 on the pile top of the pipe pile 5 and the pile top of the wedge pile 4 may include the following steps:

In step C-1, the earthwork of the crown beam 1 is excavated by mechanical partitions. The first layer of earthwork is excavated to the pile top elevation of the wedge pile 4. After removing the remaining soil, the pile head laitance is removed to the design elevation. The concrete should be chiseled to remove the scum at the top of the pile. If the strength of the pile head concrete at the design elevation fails to meet the design requirements, continue to break until the quality of the concrete meets the design requirements.

In step C-2, the soil between the piles is leveled to the bottom elevation of the crown beam 1, and compacted by ramming.

Step C-3, according to the section of crown beam 1, the reinforcement is made. Longitudinal bars use HRB335 or HRB400 steel bars, stirrups use HPB300 steel bars, and tie bars use HRB335 steel bars.

Step C-4, complete the concrete pouring and curing; the concrete strength grade is higher than or equal to C25, and the main reinforcement of the row pile is anchored into the crown beam 1, which is greater than or equal to 35 times the diameter of the reinforcement pile.

The structure, construction method and working principle of the present invention are further described below with a preferred embodiment of the present invention:

Please refer to FIG. 1, a combined support structure of inclined pipe piles and vertical wedge piles, including several pipe piles 5 and several wedge piles 4, the pipe piles 5 and the wedge piles 4 are alternately arranged to form equal lengths Combined support structure; the axis of the wedge-shaped pile 4 is perpendicular to the horizontal plane, and the area of its cross-section decreases sequentially from the top of the pile to the bottom of the pile; the axis of the pipe pile 5 is inclined to the horizontal plane and its lower part is inclined to the foundation pit; The center line of the pile top of the pipe pile 5 is parallel to the center line of the pile top of the wedge-shaped pile 4 . The inner side of the center line of the pile top; a crown beam 1 is provided on the pile top of the pipe pile 5 and the pile top of the wedge-shaped pile 4 .

The wedge-shaped piles 4 are vertical support piles, the pipe piles 5 are inclination support piles, and the crown beam 1 connects all the wedge-shaped piles and all the pipe piles into one. A water-proof curtain is arranged on the outer side of the center line of the pile top of the wedge-shaped pile 4 .

The basic principle of the present invention is:

The tubular piles 5 and the wedge-shaped piles 4 are alternately arranged to form a combined support structure. When the vertical support piles are the wedge-shaped piles 4 and the inward-inclined support piles are the tubular piles 5, the tubular piles 5 and the wedge-shaped piles 4 are alternately arranged to form a combined support structure. The structure is also known as the inclined-straight alternate support structure. The pipe pile 5 and the wedge-shaped pile 4 form a whole through the connection of the pile top, crown beam 1, and are jointly stressed. Among them, the pipe pile 5 is under compression, and the wedge-shaped pile 4 is under tension. Through the crown beam 1 , the wedge-shaped pile 4 provides its own axial force to the pipe pile 5 , which can give a downward pulling force to the pipe pile 5 .

This tensile force can effectively reduce the deformation of the pile body, thereby reducing the deformation of the soil body of the foundation pit, protecting the surrounding buildings, increasing the excavation depth H ₁ of the foundation pit, and enhancing the stability of the foundation pit. When the vertical supporting pile adopts wedge-shaped pile 4 for foundation pit support, since the area of the cross-section of the pile body decreases from the top of the pile to the bottom of the pile, the contact between the wedge-shaped pile and the soil, especially the better soil layer at the bottom is increased. The area can effectively increase the side friction resistance, thereby increasing the wedge pile tension and further controlling the displacement of the foundation pit.

Compared with other supporting structures, the present invention can effectively exert the tensile force of the wedge-shaped piles 4, so the length _H2 of the wedge-shaped piles can be shortened, the pile spacing of the supporting piles can be increased, and the pile diameter of the supporting piles can be reduced. Before construction, it is necessary to determine the optimal inclination angle of the pipe pile according to the site conditions and calculation analysis, and design the pile length and the strength of the pile body of the wedge pile 4 and the pipe pile 5. The invention is suitable for the support mode of the cantilever pile. The present invention recommends that the inclination angle of the pipe pile 5 is greater than 0° and less than or equal to 30.5°; the depth of the pile bottom of the wedge-shaped pile 4 and the pipe pile 5 is 2 to 2.5 times the excavation depth H ₁ of the foundation pit; the adjacent wedge-shaped pile 4 and the pipe pile 5 The pile spacing is 2 to 2.5 times the pile diameter. The pile diameter of the pipe pile 5 is 300-600 mm, the pile head diameter of the wedge-shaped pile 4 is about 600-1200 mm, and the pile bottom pile diameter of the wedge-shaped pile 4 is 300-600 mm.

A construction method of a combined support structure of inclined pipe piles and vertical wedge piles:

Prefabricate pipe piles 5 and wedge piles 4 of equal length; lay pipe piles 5 and wedge piles 4 on site, so that pipe piles 5 and wedge piles 4 are alternately arranged; make the axis of wedge pile 4 perpendicular to the horizontal plane and the area of its cross section from The top of the pile to the bottom of the pile becomes smaller in turn; the axis of the pipe pile 5 is inclined to the horizontal plane and its lower part is inclined to the foundation pit; The pile 4 is arranged along the inner side of the edge 3 of the foundation pit, so that the pipe pile 5 is located on the inner side of the center line of the pile top of the wedge-shaped pile 4; Root prefabricated pile; prefabricated crown beam 1 on the pile top of the pipe pile 5 and the pile top of the wedge pile 4.

The construction method of the above-mentioned wedge pile 4 is as follows:

1) On the target foundation, wedge-shaped piles 4 are formed into holes, and holes with diameters gradually decreasing from top to bottom are dug.

2) After forming the hole, first lay a concrete cushion at the end of the pile.

3) After the wedge-shaped pile 4 is hoisted and lowered, concrete is poured into the hollow section, and it is vibrated and compacted while pouring.

4) Cap assembly: After the pouring is completed, excavate the cap foundation pit, and align the bolt holes and grouting holes of the cap plate with the fixing bolts and grouting conduits of the top section of the pile, so that the cap plate and the side walls can be assembled. Fit closely with the wedge-shaped pile 4, backfill the foundation pit of the cap, and fill the edge tightly.

5) Conduit grouting: After the installation is completed, use cement slurry to grouting the conduit until the soil layer on the side of the pile has cement grout.

When the pile center distance is less than or equal to 4 times the pile diameter, the piles are denser and should be driven symmetrically from the middle to both sides. In this way, the soil body is squeezed from all sides to both sides during pile driving to ensure the construction quality. When the number of piles is large, it can also be applied in sections. When the pile center distance is greater than or equal to 4 times the side length or the pile diameter, the piles are sparse, and the above application sequence or the method of applying one side to a single direction can be used.

Let the length of the wedge-shaped pile 4 be L, and set the cement mixing pile water-proof curtain on the outside of the connection line of the pile top center of the wedge-shaped pile 4 and at a distance of 0.2L from the connection line of the pile top center of the wedge-shaped pile 4; It is the same as the bottom elevation of the wedge pile 4.

The construction method of the above-mentioned cement mixing pile waterproof curtain:

1) Positioning: The deep mixer reaches the designated pile position and aligns.

2) Pre-mixing and sinking: After the cooling water circulation of the deep mixer is normal, start the motor of the mixer, loosen the sling of the mixer, and let the mixer stir and cut the soil along the guide frame and sink.

3) Preparation of cement slurry: When the deep mixer sinks to a certain depth, it starts to mix the cement slurry according to the mixing ratio determined by the design, and pours the cement slurry into the collecting hopper before grouting.

4) Lifting and mixing: After the deep mixer sinks to the design depth, turn on the mortar pump to press the cement slurry into the foundation, and rotate while spraying, and at the same time lift the deep mixer in strict accordance with the lifting speed determined by the design.

5) Repeat up and down mixing: When the deep mixer is lifted to the top elevation of the design depth, the cement slurry in the hopper should be just emptied. In order to mix the soft soil and the cement slurry evenly, the mixer can be sunk into the soil while rotating again, and the mixer can be lifted out of the ground after reaching the designed reinforcement depth.

6) Cleaning: Clean the remaining cement slurry in all pipelines, and clean the soft soil adhering to the mixing head.

7) Shift: Move the deep mixer to the next pile position and repeat the above steps.

The crown beam 1 is arranged on the top of the wedge pile 4 and the pipe pile 5 . It is recommended that the width of the crown beam 1 is greater than the diameter of the pipe pile 5 or the top pile diameter of the wedge pile 4. The height of the crown beam 1 can be greater than or equal to 0.6 times the diameter of the pipe pile 5 or 0.6 times the average pile diameter of the wedge pile 4. . The crown beam 1 is expanded by 1/2 of the pile diameter of the pipe pile 5 or 1/2 of the average pile diameter of the wedge-shaped pile 4 on both sides in the width direction.

The construction method of the above-mentioned crown beam 1 is:

1) The earthwork of crown beam 1 is excavated by mechanical partitions. The first layer of earthwork is excavated to the design pile top elevation of the supporting pile. After removing the remaining soil, the pile head floating slurry is removed to the design elevation. The concrete on the top surface of the pile core shall be chiseled. If the strength of the pile head concrete at the design elevation does not meet the design requirements, it must continue to be removed until the quality of the concrete meets the design requirements.

2) The soil between the piles is artificially leveled to the bottom elevation of the crown beam 1, and compacted by ramming.

3) After the pile head is broken, the reinforcement can be made according to the section 1 of the crown beam. Rebar cutting and binding errors ensure that the design and construction specifications are met.

4) Check the elevation of crown beam 1 and install the formwork. When the formwork is supported, it must be ensured that the formwork is stable and firm to prevent the formwork from being deformed when the concrete is poured.

5) Complete the reinforcement works. Longitudinal reinforcement is best to use HRB335 or HRB400 steel, stirrups and tie bars should use HPB300 and HRB335 steel.

6) Complete the concrete pouring and curing. The concrete strength grade should not be lower than C25, and the anchoring of the main reinforcement of the row piles into the crown beam 1 should not be less than 35d (d is the diameter of the reinforced pile).

The above-mentioned embodiments are only used to illustrate the technical idea and characteristics of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement them accordingly, and the present invention cannot be limited only by the present embodiment. The patent scope, that is, all equivalent changes or modifications made to the spirit disclosed in the present invention, still fall within the patent scope of the present invention.

Claims (10)

1. A combined supporting structure of an inclined pipe pile and a vertical wedge-shaped pile is characterized by comprising a row pile supporting structure formed by alternately arranging pipe piles and wedge-shaped piles; the tubular pile and the wedge-shaped pile are arranged along the inner side of the edge of the foundation pit, and a crown beam is arranged on the pile top of the tubular pile and the wedge-shaped pile; the axis of the wedge-shaped pile is vertical to the horizontal plane, and the area of the cross section of the wedge-shaped pile is sequentially reduced from the pile top to the pile bottom; the axis of the tubular pile is inclined to the horizontal plane, and the lower part of the tubular pile is inclined towards the inside of the foundation pit; and the pile top central connecting line of the tubular pile is parallel to or coincided with the pile top central connecting line of the wedge-shaped pile.

2. The combined supporting structure of an inclined pipe pile and a vertical wedge-shaped pile according to claim 1, wherein an included angle between an axis of the pipe pile and an axis of the wedge-shaped pile is not more than 30 degrees.

3. The combined supporting structure of the inclined tubular pile and the vertical wedge-shaped pile according to claim 1, wherein the depth of the pile bottom of the tubular pile or the wedge-shaped pile is 2-2.5 times of the excavation depth of a foundation pit.

4. The combined supporting structure of the inclined tubular pile and the vertical wedge-shaped pile according to claim 1, wherein the diameter of the tubular pile is 300-600 mm; the pile top diameter of the wedge-shaped pile is 600-1200 mm, and the wedge angle of the wedge-shaped pile is 5-15 degrees.

5. The combined supporting structure of an inclined tubular pile and a vertical wedge-shaped pile according to claim 1, wherein the width direction edge of the crown beam exceeds the tubular pile and the pile top edge of the wedge-shaped pile, and the height of the crown beam is greater than or equal to 0.6 time of the pile diameter of the tubular pile or 0.6 time of the average pile diameter of the wedge-shaped pile.

6. The combined supporting structure of an inclined pipe pile and a vertical wedge-shaped pile according to claim 5, wherein the dimension of the width direction edge of the crown beam beyond the pile top edges of the pipe pile and the wedge-shaped pile on one side is as follows: 1/2 pile diameter or 1/2 wedge pile average pile diameter.

7. A construction method of a combined supporting structure of an inclined pipe pile and a vertical wedge-shaped pile is characterized by comprising the following steps: prefabricating a tubular pile and a wedge-shaped pile; arranging tubular piles and wedge-shaped piles along the inner side of the edge of the foundation pit on site, and enabling the tubular piles and the wedge-shaped piles to be alternately arranged to form a pile arrangement supporting structure; the axis of the wedge-shaped pile is vertical to the horizontal plane, and the area of the cross section of the wedge-shaped pile is reduced from the pile top to the pile bottom in sequence; the axis of the tubular pile is inclined to the horizontal plane, and the lower part of the tubular pile is inclined to the inside of the foundation pit; enabling a pile top central connecting line of the tubular pile and a pile top central connecting line of the wedge-shaped pile to be parallel or coincident, adopting a pile jumping construction method for the tubular pile and the wedge-shaped pile, and pressing a next precast pile at intervals of 1-2 piles; and (4) prefabricating a crown beam on the pile top of the tubular pile and the pile top of the wedge-shaped pile.

8. The construction method of a combined supporting structure of an inclined pipe pile and a vertical wedge-shaped pile according to claim 7, wherein the method for laying the wedge-shaped pile in the field comprises the following steps:

step A-1, performing wedge pile hole forming operation on a target foundation to ensure that the hole diameter of the excavated hole is gradually reduced from top to bottom;

step A-2, after hole forming, paving a concrete cushion layer at the hole bottom;

step A-3, after the wedge-shaped pile is lifted and sunk, pouring concrete into the hollow section, and vibrating and compacting while pouring;

step A-4, after pouring, excavating a bearing platform foundation pit, aligning a bolt hole and a grouting hole of a bearing platform cover plate with a fixing bolt and a grouting guide pipe of a wedge-shaped pile top section correspondingly, attaching the bearing platform cover plate to the pile top of the wedge-shaped pile and the side wall of the bearing platform foundation pit, backfilling the bearing platform foundation pit, and filling the edge tightly;

and step A-5, grouting the guide pipe by adopting cement paste until cement paste is spread out from the soil layer on the side of the pile.

9. The construction method of a combined supporting structure of an inclined tubular pile and a vertical wedge-shaped pile according to claim 7, characterized in that the length of the wedge-shaped pile is set to be L, and a cement mixing pile waterproof curtain is arranged at the position which is outside the center connecting line of the pile tops of the wedge-shaped piles and is 0.2L away from the center connecting line of the pile tops of the wedge-shaped piles; the construction method of the waterproof curtain of the cement mixing pile comprises the following steps:

b-1, enabling the deep layer stirrer to reach the designated pile position and centering;

b-2, after the cooling water circulation of the deep layer stirrer is normal, starting the deep layer stirrer to enable the deep layer stirrer to stir along the guide frame, cut soil and sink;

step B-3, when the deep layer stirrer sinks to a set depth, stirring cement paste and pouring the cement paste into a collecting hopper;

step B-4, after the deep layer stirrer sinks to the designed depth, starting a cement slurry pump to press cement slurry into the foundation, spraying the cement slurry and rotating and stirring the cement slurry, and simultaneously lifting the deep layer stirrer according to the lifting speed determined by the design;

and step B-5, after the deep layer stirring machine is lifted to the top surface elevation of the designed depth, the deep layer stirring machine is sunk into the soil while rotating and stirring, and the deep layer stirring machine is lifted out of the ground after the design depth.

10. The construction method of a combined supporting structure of an inclined pipe pile and a vertical wedge-shaped pile according to claim 7, wherein the method of prefabricating a crown beam on the pile top of the pipe pile and the pile top of the wedge-shaped pile comprises the steps of:

c-1, excavating the earthwork of the crown beam in a mechanical partition mode, excavating a first layer of earthwork to reach the pile top elevation of the wedge-shaped pile, removing residual soil, then beginning to remove pile head floating slurry to reach the designed elevation, chiseling the concrete on the top surface of the pile core, removing the pile top floating slurry, and continuing to remove the pile head floating slurry until the concrete quality reaches the designed requirement if the pile head concrete strength at the designed elevation does not reach the designed requirement;

c-2, leveling the soil between the piles to the elevation of the bottom of the crown beam, and compacting by tamping;

c-3, manufacturing steel bars according to the cross section reinforcements of the crown beam; the longitudinal bars adopt HRB335 grade or HRB400 grade steel bars, and the stirrups adopt HPB300 grade steel bars; the tie bars are HRB 335-grade steel bars;

c-4, completing concrete pouring and curing; the concrete strength grade is higher than or equal to C25, and the main reinforcement of the row pile is anchored into the crown beam and is more than or equal to 35 times of the diameter of the reinforced pile.

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