CN111962520A - A combined support structure of inclined bamboo piles and vertical pipe piles and construction method thereof - Google Patents

Abstract

The invention discloses a combined support structure of inclined bamboo piles and vertical pipe piles, which comprises a row pile support structure composed of pipe piles and bamboo piles alternately arranged; The edge of the foundation pit is arranged on the inner side, and crown beams are arranged on the tops of the pipe piles and the bamboo-joint piles; the bamboo-joint piles have their axes inclined to the horizontal plane and their lower parts are inclined toward the foundation pit, and the outer surface of the pile body is There are several annular protrusions perpendicular to its axis, and annular reinforcing ribs are arranged in the annular protrusion; the axis of the pipe pile is perpendicular to the horizontal plane; the center line of the pile top of the pipe pile and the pile of the bamboo pile Top center lines are parallel or coincident. The invention also discloses a construction method of the combined support structure of the inclined bamboo pile and the vertical pipe 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 bamboo piles and vertical pipe piles and construction method thereof

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 bamboo pile and a vertical pipe 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 an inclined bamboo pile and a vertical pipe pile 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 bamboo piles and vertical pipe piles, including row pile supports formed by alternately arranging pipe piles and bamboo piles protective structure; the pipe piles and the bamboo piles are arranged along the inner side of the edge of the foundation pit, and a crown beam is provided on the tops of the pipe piles and the bamboo piles; the bamboo piles, whose axes are inclined to The horizontal plane and its lower part are inclined into the foundation pit, the outer surface of the pile body is provided with a number of annular protrusions perpendicular to its axis, and the annular protrusion is provided with annular reinforcing ribs; the axis of the pipe pile is perpendicular to the horizontal plane; the pipe pile The center line of the pile top is parallel or coincident with the center line of the pile top of the bamboo pile.

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

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

Further, the spacing of the annular protrusions of the bamboo stakes is gradually reduced along the axis direction.

Further, the diameter of the pipe pile is 300-600mm; the diameter of the bamboo-joint pile is 300-600mm, and the height of the annular protrusion of the bamboo-joint pile protruding from the surface of the pile body is 10% to 10% of the pile diameter. 30%.

Further, the width direction edge of the crown beam exceeds the pile top edge of the pipe pile and the bamboo 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 diameter of the bamboo pile. times.

Further, the size of the unilateral edge of the crown beam extending beyond the top edge of the pipe pile and the bamboo pile is: 1/2 the diameter of the pipe pile or 1/2 the diameter of the bamboo pile.

The invention also provides a method for constructing a combined support structure of an inclined bamboo pile and a vertical pipe pile, the method comprising: prefabricating the pipe pile and the bamboo pile; The annular protrusion of its axis is provided with annular reinforcing ribs; pipe piles and bamboo piles are arranged along the inner side of the edge of the foundation pit on the site, so that the pipe piles and bamboo piles are alternately arranged to form a row pile supporting structure; The axis of the section pile is inclined to the horizontal plane and its lower part is inclined to the foundation pit; the axis of the pipe pile is perpendicular to the horizontal plane; the center line of the pile top of the pipe pile is parallel or coincident with the center line of the bamboo pile. Bamboo piles are constructed by jumping piles, and the next prefabricated pile is pressed into the next prefabricated pile at intervals of 1 to 2; the crown beams are prefabricated on the pile tops of the pipe piles and the bamboo piles.

Further, set the length of the pipe 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 pipe pile and at 0.2L from the center connection line of the pile top of the pipe pile; the construction method of the cement mixing pile water-proof curtain It includes the following steps:

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

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

Step A-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 A-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 crown beams on the pile tops of the pipe piles and the bamboo joint piles comprises the following steps:

Step B-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 pipe pile. After removing the remaining soil, the pile head slurries are 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 B-2, the soil between the piles is leveled to the bottom elevation of the crown beam, and compacted by ramming;

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

The advantages and positive effects of the present invention are as follows: a combined support structure of an inclined bamboo stake and a vertical pipe pile of the present invention, the tubular piles and the bamboo stakes are alternately arranged to form an equal-height combined support structure, so that the The axis is perpendicular to the horizontal plane; the axis of the bamboo pile is inclined to the horizontal plane and its lower part is inclined to the foundation pit; the annular protrusion of the bamboo pile can increase the lateral friction resistance, so that the axial force can be fully exerted, giving the pipe pile a greater The diagonal bracing force can greatly reduce the displacement of the pile top, so that the ground deformation is reduced after the supporting piles are laid, so as to avoid damage to the surrounding environment, and at the same time, it can reduce the bending moment of the pile body and reduce the design strength of the pile body, thereby reducing the Engineering cost; the invention can increase the excavation depth, and because the excavation surface is inclined, the bamboo joint pile has high bearing capacity, and the settlement is small, the possibility of overturning damage of the foundation pit is greatly reduced, and the safety of the foundation pit project can be guaranteed; The combined support structure of the inclined bamboo piles and the vertical pipe piles of the present invention makes it possible to use only cantilever piles for support in foundation pit projects that may originally require internal support or anchor support. To meet the design 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 bamboo pile and a vertical pipe pile according to the present invention.

In the picture: 1- Crown beam; 2- Foundation pit bottom; 3- Foundation pit edge; 4- Bamboo pile; 5- Pipe pile; 6- Ring-shaped protrusion.

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

In the figure: H ₁ - excavation depth of foundation pit; H ₂ - length of pipe pile; θ - inclination angle of bamboo 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 bamboo piles and vertical pipe piles, including a pile row support structure composed of pipe piles 5 and bamboo piles 4 alternately arranged; the pipe piles 5 and described bamboo stake 4 along the inner side of foundation pit edge 3, and crown beam 1 is provided on the top of described pipe pile 5 and described bamboo stake 4; the outer surface of the pile body of described bamboo stake 4 There are several annular protrusions 6 perpendicular to the axis of the bamboo stake 4, and annular reinforcing ribs are provided in the annular protrusion 6 of the bamboo stake 4; the axis of the bamboo stake 4 is inclined to the horizontal plane and the lower part thereof The pit is inclined; the axis of the pipe pile 5 is perpendicular to the horizontal plane; 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 bamboo pile. The tops of the pipe piles 5 and the bamboo piles 4 are located on the inner side of the edge 3 of the foundation pit, and the pipe piles 5 and the bamboo piles 4 are connected by the crown beam 1 to form a whole. The annular reinforcing rib may include several radially distributed radial reinforcing bars and several concentric annular reinforcing bars connected with the radial reinforcing bars to form a spider web-shaped annular reinforcing rib. The annular reinforcing rib can also be an annular reinforcing rib of other structures.

The bamboo pile may include a tubular pile body, and a plurality of concrete reinforcing rings are distributed at intervals along the axial direction on the outer surface of the tubular pile body. The pile body is formed into a concave and convex shape, hence the name bamboo pile. It is a special type of prestressed pipe pile. Due to the unevenness of the pile body, the lateral friction increases after the pile is driven, and the bearing capacity of the end-bearing friction pile and the friction pile is improved, usually by 10%-15%. Can be used for both compression and pull-out. Bamboo piles are mechanically connected, and the pile connection is relatively simple. Before the pile is driven, a special wrench shall be used to screw the connecting nut into the thread reserved at the pile end. When connecting the pile, the butt end of the pile shall be smeared with epoxy (sealing effect), and then the connecting nut of the upper pile shall be aligned and snapped into place. The pile connection is completed in the circlip reserved for the lower pile.

The distance between the annular protrusions 6 of the bamboo stake can be equidistant or unequal along the axis direction. When the distance is unequal, the distance between the annular protrusions 6 of the bamboo stake gradually decreases along the axis direction.

The center line of the top of the bamboo pile 4 can be located on the inner side of the center line of the top of the pipe pile 5; The diameter of the pile or 2 to 4 times the diameter of the bamboo pile.

The inclination angle of the axis of the pipe pile 5 relative to the axis of the bamboo pile 4 is greater than 0°, and within the range of 0° to 30.5°, the angle between the axis of the pipe pile and the axis of the bamboo pile is preferably ≤30°. As shown in FIG. 2 , the included angle between the axis of the pipe pile and the axis of the bamboo pile can be referred to as the bamboo pile inclination angle θ, and the bamboo pile inclination angle θ can be ≤30°. The inclination angle θ of the bamboo stake can be preferably 10°, 12°, 15°, 18°, 21°, 24°.

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

The diameter of the pipe pile can be 300-600mm; the diameter of the bamboo pile can be 300-600mm, and the height of the annular protrusion 6 of the bamboo pile protruding from the surface of the pile body can be 10% of the pile diameter ~30%.

Crown beams 1 are arranged on bamboo 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 bamboo pile 4 connected with it, and the width direction edge of the crown beam 1 can exceed the pile top of the pipe pile 5 and the bamboo pile 4 Edge, 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 diameter of the bamboo pile 4 .

Further, the size of the unilateral edge of the width direction edge of the crown beam 1 beyond the pile top edge of the pipe pile 5 and the bamboo pile 4 can be: 1/2 the diameter of the pipe pile 5 or 1/2 bamboo Pile diameter of section pile 4.

The length of the pipe pile 5 can be set to be L, and the cement mixing pile water-proof curtain can be set on the outside of the connection line of the pile top center of the pipe pile 5 and 0.2L away from the connection line of the pile top center of the pipe pile 5 .

The present invention also provides an embodiment of a method for constructing a combined support structure of an inclined bamboo pile and a vertical pipe pile. The method includes: prefabricating a pipe pile 5 and a bamboo pile 4; There are several annular protrusions 6 perpendicular to the axis of the bamboo piles, the spacing of the annular protrusions 6 is equal or unequal spacing, and annular reinforcing ribs are provided in the annular protrusion 6; and bamboo pile 4, make the pipe pile 5 and the bamboo pile 4 alternately arranged to form a pile row support structure; make the axis of the pipe pile 5 perpendicular to the horizontal plane; make the axis of the bamboo pile 4 inclined to the horizontal plane and its lower part is in the foundation pit Tilt; make the center line of the top of the pipe pile 5 and the center line of the top of the bamboo pile 4 parallel or coincident, the pipe pile 5 and the bamboo pile 4 all adopt the construction method of jumping piles, and the interval is 1 to 2 piles to be pressed into The next prefabricated pile; the crown beam 1 is prefabricated on the top of the pipe pile 5 and the top of the bamboo pile 4. The center line of the top of the bamboo pile 4 can be located on the inner side of the center line of the top of the pipe pile 5; The pile diameter of the pile or 2 to 4 times the pile diameter of the bamboo pile.

Further, the construction sequence of laying pipe piles 5 and bamboo piles 4 along the inner side of the foundation pit on the site: when the pile center distance is less than or equal to 4 times the pile diameter, the piles are denser and should be applied symmetrically from the middle to both sides, so that , When piling, the soil is squeezed from all sides to both sides to ensure the construction quality. When the number of piles is large, it can also be applied in sections. When the distance between the centers of the piles is greater than 4 times the pile diameter, the piles are relatively sparse.

Further, the length of the pipe pile 5 can be set to be L, and the cement mixing pile water-proof curtain can be set at the outer side of the center line of the pile top of the pipe pile 5 and 0.2L away from the center line of the pile top of the pipe pile 5 . The construction method of the water-proof curtain for cement mixing piles may include the following steps:

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

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

Step A-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 A-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 top of the pipe pile 5 and the top of the bamboo pile 4 may include the following steps:

In step B-1, the earthwork of the crown beam 1 is excavated by mechanical partitions. First, the first layer of earthwork is excavated to the pile top elevation of the pipe pile 5. After removing the remaining soil, the pile head floating slurry 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 B-2, the soil between the piles is leveled to the bottom elevation of the crown beam 1, and compacted by ramming.

Step B-3, according to the section of crown beam 1, the reinforcement is made. The longitudinal reinforcement adopts HRB335 grade or HRB400 grade steel bar, and the stirrup adopts HPB300 grade steel bar. The tie bars are made of HRB335 steel bars.

Step B-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 or more than 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 kind of combined support structure of inclined bamboo stakes and vertical pipe piles, consisting of tubular stakes 5 and bamboo stakes 4 alternately arranged to form a pile support structure; the tubular stakes 5 and the bamboo stakes The pile 4 is arranged along the inner side of the edge 3 of the foundation pit, and the crown beam 1 is arranged on the top of the pipe pile 5 and the bamboo pile 4; the outer surface of the pile body of the bamboo pile 4 is provided with several The annular protrusion 6, the annular protrusion 6 of the bamboo stake 4 is provided with an annular reinforcing rib; the axis of the bamboo stake 4 is inclined to the horizontal plane and the lower part thereof is inclined to the foundation pit; the axis of the pipe pile 5 is vertical In the horizontal plane, the center line of the pile top of the pipe pile 5 is parallel or coincident with the center line of the pile top of the bamboo pile 4 . The annular reinforcing bar is composed of radial radial reinforcing bars and several annular reinforcing bars connected with the radial reinforcing bars.

The pipe piles 5 are vertical support piles, the bamboo joint piles 4 are inwardly inclined support piles, and the crown beam 1 connects all the bamboo joint piles and all the pipe piles into one. A water-proof curtain is arranged on the outer side of the center line connecting the pile tops of the pipe piles 5 . The bottom elevation of the stirring pile of the water-proof curtain is the same as the bottom elevation of the combined oblique-straight alternating support pile.

The basic principle of the present invention is:

The pipe piles 5 and the bamboo piles 4 are alternately arranged to form a combined support structure. When the pipe piles 5 are vertical support piles and the bamboo piles 4 are inclination support piles, the bamboo piles 4 and the pipe piles 5 are arranged alternately. The combined support structure is also called the inclined-straight alternate support structure. The pipe pile 5 and the bamboo pile 4 are connected to form a whole through the pile top, crown beam 1, and are jointly stressed. Among them, the inwardly inclined supporting piles are in compression, and the vertical supporting piles are in tension. Through the crown beam 1, the inwardly inclined support piles provide their own axial force to the vertical support piles, which can give the vertical support piles an oblique upward supporting force. related.

This oblique upward supporting 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 of the foundation pit, and enhancing the stability of the foundation pit. When the bamboo-joint piles 4 are used for foundation pit support for the inwardly inclined support piles, the annular protrusion 6 of the bamboo-joint piles 4 increases the contact area between the bamboo-joint piles 4 and the soil, especially the better soil layer at the bottom, which can effectively Increasing the side friction resistance increases the contact area between the support structure and the soil, especially the better soil layer at the bottom, which can effectively increase the side friction resistance, thereby increasing the support force in the oblique upward direction and further controlling the displacement of the foundation pit.

The present invention can effectively exert the diagonal bracing force, so it can reduce the inclination angle of the inwardly inclined support piles, shorten the pile length of each support pile, for example, can reduce the pile length _H2 of the pipe pile and the pile length of the bamboo pile 4, and increase the length of the piles. The pile spacing of large supporting piles is reduced, and the pile diameter of supporting piles is reduced. Before construction, it is necessary to determine the optimal inclined-straight alternate support structure and the inclination angle of the inclination support pile relative to the vertical support pile according to the site conditions and calculation analysis, and design the length of the pile and the strength of the pile body. The present invention is only applicable to the support mode of the cantilever pile. The present invention recommends that the inclination angle of the inclination support pile, that is, the bamboo-joint pile 4, is greater than 0° and less than or equal to 30.5°; the depth of the pile bottom of the bamboo-joint pile 4 and the pipe pile 5 is 2 to 2.5 times the excavation depth H ₁ of the foundation pit; The distance between the adjacent bamboo piles 4 and the pipe piles 5 is 2 to 2.5 times the diameter of the piles. The diameter of the pipe pile 5 may be 300-600 mm, and the diameter of the bottom of the bamboo pile 4 may be 300-600 mm. The height of the annular protrusion 6 of the bamboo stake protruding from the surface of the pile body may be 15% to 20% of the diameter of the pile.

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

Prefabricated pipe piles 5 and bamboo stakes 4 of equal length; make the outer surface of the pile body of the bamboo stakes provided with some annular projections 6 perpendicular to the axis of the bamboo stakes, the annular projections 6 are equidistant, and the annular projections 6 There is a ring-shaped reinforcing rib in it; pipe piles 5 and bamboo piles 4 are arranged on site, so that the pipe piles 5 and bamboo piles 4 are arranged alternately; the axis of the pipe pile 5 is perpendicular to the horizontal plane; the axis of the bamboo pile 4 is inclined to The horizontal plane and its lower part are inclined in the foundation pit; the center connection line of the pile top of the pipe pile 5 is parallel to the center connection line of the pile top of the bamboo pile 4, and the bamboo pile 4 is arranged along the inner side of the edge 3 of the foundation pit, so that the pipe pile 5 is located at the inner side of the foundation pit edge 3. The inner side of the center connection line of the pile top of the bamboo pile 4; the pipe pile 5 and the bamboo pile 4 both adopt the construction method of jumping piles, and the next prefabricated pile is pressed into the next prefabricated pile at intervals of 1 to 2; The crown beam 1 is prefabricated on the top of the section pile 4 .

The construction method of above-mentioned bamboo stake 4 is as follows:

1) After the pile tip is installed on the small nut end of the bottom pile, start piling. Pile into the soil about 50 cm to adjust the verticality. When the first section of piles are inserted into the ground, the deviation of verticality shall not exceed 0.3%. When the bottom pile is buried more than 1/3 of the pile, the pile driver shall not be forcibly moved again to adjust the verticality. When the pile body is inclined, the cause should be identified before construction. To avoid the pile body being forcibly adjusted and broken or injured.

2) After adjusting the verticality, start the pile driving. When driving the pile, pay attention to the position of the clamp. The clamp should be clamped at the protruding position of the bamboo pile. It is forbidden to clamp it at the concave part and the position above 20 cm from the end of the bamboo pile. These two parts are the most vulnerable parts of the bamboo pile. s position.

3) When the distance between the top of the first section of the pile and the cantilever of the pile driver is 40 cm, stop the pile pressing. Pour the mixture of epoxy resin and curing agent on the large nut end of the pile, and pour it on the pile head with a circle inside and outside.

4) The upper and lower section piles are connected by a snap-on mechanical connection.

The length of the pipe pile 5 is set to be L, and the cement mixing pile water-proof curtain is set on the outside of the connection line of the pile top center of the pipe pile 5 and 0.2L away from the connection line of the pile top center of the pipe pile 5; It is the same as the pile bottom elevation of the pipe pile 5 .

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.

A crown beam 1 is arranged on the bamboo piles 4 and the pipe piles 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 bamboo 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 the diameter of the bamboo pile 4. 0.6 times. The crown beam 1 is expanded by 1/2 of the pile diameter of the pipe pile 5 or 1/2 of the pile diameter of the bamboo 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 inclined bamboo joint piles and vertical tubular piles is characterized by comprising a row pile supporting structure formed by alternately arranging tubular piles and bamboo joint piles; the tubular pile and the bamboo joint pile are arranged along the inner side of the edge of the foundation pit, and the pile tops of the tubular pile and the bamboo joint pile are provided with crown beams; the axis of the bamboo joint pile is inclined to the horizontal plane, the lower part of the bamboo joint pile is inclined to the interior of the foundation pit, a plurality of annular bulges vertical to the axis of the bamboo joint pile are arranged on the outer surface of the pile body of the bamboo joint pile, and annular reinforcing ribs are arranged in the annular bulges; the axis of the tubular pile is vertical to the horizontal plane; the pile top center connecting line of the tubular pile is parallel to or coincided with the pile top center connecting line of the bamboo joint pile.

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

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

4. The combined supporting structure of the inclined bamboo joint piles and the vertical pipe piles according to claim 1, wherein the distance between the annular protrusions of the bamboo joint piles is gradually reduced along the axial direction.

5. The combined supporting structure of the inclined bamboo joint piles and the vertical tubular piles according to claim 1, wherein the pile diameter of the tubular pile is 300-600 mm; the pile diameter of the bamboo joint pile is 300-600 mm, and the height of the annular bulge of the bamboo joint pile, which protrudes out of the surface of the pile body, is 10% -30% of the pile diameter.

6. The combined supporting structure of the inclined bamboo-joint pile and the vertical tubular 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 bamboo-joint 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 pile diameter of the bamboo-joint pile.

7. The combined supporting structure of the inclined bamboo-joint pile and the vertical pipe pile according to claim 6, wherein the dimension of the width-direction edge of the crown beam beyond the top edges of the pipe pile and the bamboo-joint pile is as follows: 1/2 pile diameter of tubular pile or 1/2 bamboo joint pile diameter.

8. A construction method of a combined supporting structure of an inclined bamboo joint pile and a vertical pipe pile is characterized by comprising the following steps: prefabricating a tubular pile and a bamboo joint pile; the outer surface of the pile body of the bamboo joint pile is provided with a plurality of annular bulges vertical to the axial line of the pile body, and annular reinforcing ribs are arranged in the annular bulges; arranging pipe piles and bamboo joint piles along the inner side of the edge of the foundation pit on site, and enabling the pipe piles and the bamboo joint piles to be alternately arranged to form a pile arrangement supporting structure; the axis of the bamboo joint pile is inclined to the horizontal plane, and the lower part of the bamboo joint pile is inclined towards the inside of the foundation pit; making the axis of the pipe pile vertical to the horizontal plane; enabling a pile top central connecting line of the tubular pile and a pile top central connecting line of the bamboo joint pile to be parallel or coincident, adopting a pile jumping construction method for the tubular pile and the bamboo joint pile, and pressing the tubular pile and the bamboo joint pile into the 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 bamboo-joint pile.

9. The method for constructing a combined supporting structure of an inclined bamboo joint pile and a vertical tubular pile according to claim 8, wherein the length of the tubular pile is set to be L, and a cement mixing pile waterproof curtain is arranged outside a pile top center connecting line of the tubular pile and at a distance of 0.2L from the pile top center connecting line of the tubular pile; the construction method of the waterproof curtain of the cement mixing pile comprises the following steps:

a-1, enabling a deep layer stirrer to reach a specified pile position and centering;

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

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

and step A-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 bamboo joint pile and a vertical pipe pile according to claim 8, wherein the method for prefabricating the crown beam on the pile top of the pipe pile and the pile top of the bamboo joint pile comprises the following steps:

b-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 tubular pile, removing residual soil, then beginning to remove pile head floating slurry to 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 concrete until the concrete quality reaches the design requirement if the strength of the pile head concrete at the designed elevation does not reach the design requirement;

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

b-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;

b-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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