Connecting structure of large-section waist beam and secant pile and construction method

Abstract

The invention discloses a connecting structure of a large-section waist beam and a secant pile and a construction method, the waist beam is fixed on the secant pile through the connecting structure, and the connecting structure comprises anti-falling steel bars, welding steel bars and embedded steel bars; one end of the anti-falling steel bar is welded to the pile body position, above the waist beam, of the secant pile, and the other end of the anti-falling steel bar is anchored downwards to the bottom of the waist beam from the upper end of the position, away from the secant pile, of the waist beam. The embedded steel bars are L-shaped, one ends of the embedded steel bars are anchored into the waist beams, and the other ends of the embedded steel bars are embedded into pile bodies, corresponding to the mounting positions of the secant piles and the waist beams, of the secant piles; one end of the welding steel bar is welded to a main bar of the secant pile, and the other end of the welding steel bar is anchored into the waist beam. According to the connecting structure, the problems that the waist beam is large in self weight and difficult to connect with the secant piles can be solved, a connecting system formed through the construction method can meet the stress requirement, and the safety of deep foundation pit supporting and the stability of a foundation pit are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit support engineering construction, and in particular to a connection structure and a construction method of a large-section waist beam and an interlocking pile. Background Art

[0002] In the semi-enclosed deep foundation pit support, the large-section waist beam needs to be fastened and connected with the bite pile under the premise of overcoming its own weight, which is a construction problem. The conventional connection method is extremely difficult to operate in practice, and the construction conditions are not available on site. One of the conventional practices is to embed the steel bar joint in the pile during the construction of the bite pile, and then chisel out the joint and connect it with the waist beam when the waist beam of the support structure is constructed; the second method is to use rebar planting or welding measures to connect the waist beam with the bite pile during the later waist beam construction. The disadvantage of the first method is that the elevation of the pile foundation steel cage is difficult to control during the construction of the bite pile foundation, and the pile foundation steel cage often sinks or floats during construction (especially when a full-rotation drilling rig is used for construction), which leads to inaccurate positioning of the embedded steel bars and cannot be accurately connected with the waist beam. The disadvantage of the second method is that when a single rebar planting or welding connection is used, due to the small exposed surface of the bite pile, the limited number of rebar planting or welding, the limited depth of rebar planting, and the huge cross-sectional size of the waist beam, the single connection method is difficult to bear the weight of the waist beam itself and does not meet the force requirements. Summary of the invention

[0003] The purpose of the present invention is to provide a connection structure and construction method between a large-section waist beam and an interlocking pile, which adopts a combined steel bar connection of embedded reinforcement + welding + anti-falling to solve the construction force problem, ensure the effective connection between the large-section waist beam and the interlocking pile, and achieve the foundation pit force requirements and safety.

[0004] To achieve the above purpose, the technical solution provided by the present invention is:

[0005] The first aspect of the present application provides a connection structure between a large-section waist beam and an interlocking pile, wherein the waist beam is fixed to the interlocking pile through the connection structure, and the connection structure includes anti-falling steel bars, welded steel bars and embedded steel bars;

[0006] One end of the anti-falling steel bar is welded to the engaging pile body above the waist beam, and the other end of the anti-falling steel bar is anchored downward from the upper end of the waist beam away from the engaging pile to the bottom of the waist beam;

[0007] The embedded reinforcement bar is L-shaped, one end of the embedded reinforcement bar is anchored into the waist beam, and the other end of the embedded reinforcement bar is embedded in the body of the bite pile corresponding to the installation position of the waist beam; the embedded reinforcement bar includes an upper embedded reinforcement bar and a lower embedded reinforcement bar, the L inner angle of the upper embedded reinforcement bar is set corresponding to the upper inner angle of the waist beam away from the bite pile, and the L inner angle of the lower embedded reinforcement bar is set corresponding to the lower inner angle of the waist beam away from the bite pile;

[0008] The welded steel bars are in a C shape. One end of the welded steel bars is welded to the main bars of the secant pile, and the other end of the welded steel bars is anchored into the lintel beam. The welded steel bars include upper welded steel bars arranged on the upper part of the lintel beam and lower welded steel bars arranged on the lower part of the lintel beam. The C-shaped opening of the upper welded steel bars faces downward, and the C-shaped opening of the lower welded steel bars faces upward.

[0009] To optimize the above technical solution, the specific measures taken also include:

[0010] The welding position of the anti-falling steel bars on the secant pile is on the side of the secant pile close to the lintel beam.

[0011] Further, the position where the anti-falling steel bars are anchored into the lintel beam is located outside the steel bars implanted in the lintel beam, and the welded steel bars are located inside the steel bars implanted in the lintel beam.

[0012] The lintel beam is provided with lintel beam steel bars located inside the peripheral wall of the lintel beam. The upper and lower sides and the end side far from the secant pile of the implanted steel bars and the welded steel bars are all located inside the lintel beam steel bars. The steel bar section of the anti-falling steel bars anchored from the upper end of the lintel beam to the bottom of the lintel beam is also located inside the lintel beam steel bars.

[0013] Further, two upper implanted steel bars and two lower implanted steel bars are provided for one lintel beam, four upper welded steel bars are provided, and two lower welded steel bars are provided.

[0014] The second aspect of the present application provides a construction method for a connection structure between a large-section lintel beam and a secant pile, including the following steps:

[0015] Determine the installation position of the lintel beam on the secant pile according to the design elevation, drill holes at the installation position of the lintel beam on the secant pile, and install implanted steel bars in the drilled holes;

[0016] After the installation of the implanted steel bars is completed, start installing the welded steel bars, and weld one end of the welded steel bars to the main bars of the secant pile;

[0017] After the installation of the welded steel bars is completed, start installing the lintel beam steel bars;

[0018] After the installation of the lintel beam steel bars is completed, start installing the anti-falling steel bars, weld one end of the anti-falling steel bars to the pile body position of the secant pile above the installation position of the lintel beam, and anchor the other end of the anti-falling steel bars into the lintel beam steel bars at the bottom;

[0019] Carry out formwork installation and concrete pouring to form a lintel beam structure connected to the secant pile.

[0020] Further, after determining the position of the lintel beam on the secant pile, roughen the pile body of the secant pile within the installation position range of the lintel beam, remove the main bar protection layer of the secant pile within this range, and clean its surface.

[0021] Furthermore, the installation position of the embedded reinforcement bars is determined according to the position of the waist beam reinforcement bars; when installing the embedded reinforcement bars, after drilling holes on the bite piles, glue is injected into the drilled holes, and then the embedded reinforcement bars are installed.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The connection structure between the large-section waist beam and the interlocking piles of the present invention is composed of three parts of connecting steel bars, namely welding, implanting and anti-falling, to form a connection system, which can solve the problem that the waist beam itself is heavy and difficult to connect with the interlocking piles. The connection system formed by adopting this construction method can meet the force requirements and ensure the safety of deep foundation pit support and the stability of the foundation pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 : A side structural schematic diagram of the connection structure between the large-section waist beam and the interlocking piles of the present invention.

[0025] Figure 2 : A schematic top view of the connection structure between the large-section waist beam and the interlocking piles of the present invention.

[0026] In the figure: 1. Interlocking pile; 2. Waist beam; 3. Anti-falling steel bars; 4. Welded steel bars; 5. Embedded steel bars; 6. Main bars of interlocking pile; 7. Waist beam steel bars; 8. Welding points of welded steel bars. DETAILED DESCRIPTION

[0027] The above contents of the present invention are further described in detail below in the form of embodiments, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the above contents of the present invention belong to the scope of the present invention.

[0028] The orientation or position relationship is based on the relationship shown in the drawings and is only for the convenience of describing the present invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0029] The present invention provides a connection structure between a large-section waist beam and an interlocking pile, wherein the waist beam 2 is fixed on the interlocking pile 1 through the connection structure, and the connection structure includes an anti-falling steel bar 3, a welded steel bar 4 and an embedded steel bar 5;

[0030] One end of the anti-falling steel bar 3 is welded to the occlusal pile body above the waist beam 2, and the other end of the anti-falling steel bar 3 is anchored downward from the upper end of the waist beam 2 away from the occlusal pile 1 to the bottom of the waist beam 2;

[0031] The post - installed reinforcement bar 5 is L - shaped. One end of the post - installed reinforcement bar 5 is anchored into the waist beam 2, and the other end of the post - installed reinforcement bar 5 is implanted into the overlapping pile body corresponding to the installation position of the waist beam 2. The post - installed reinforcement bar 5 includes an upper post - installed reinforcement bar and a lower post - installed reinforcement bar. The L - shaped inner angle of the upper post - installed reinforcement bar corresponds to the upper inner angle of the position of the waist beam 2 far from the overlapping pile 1, and the L - shaped inner angle of the lower post - installed reinforcement bar corresponds to the lower inner angle of the position of the waist beam 2 far from the overlapping pile 1.

[0032] The welded reinforcement bar 4 is U - shaped. One end of the welded reinforcement bar 4 is welded to the main reinforcement bar of the overlapping pile 1, and the other end of the welded reinforcement bar 4 is anchored into the waist beam 2. The welded reinforcement bar 4 includes an upper welded reinforcement bar arranged on the upper part of the waist beam 2 and a lower welded reinforcement bar arranged on the lower part of the waist beam 2. The U - shaped opening of the upper welded reinforcement bar faces downwards, and the U - shaped opening of the lower welded reinforcement bar faces upwards.

[0033] The welding position of the anti - falling reinforcement bar 3 on the overlapping pile 1 is on the side of the overlapping pile 1 close to the waist beam 2.

[0034] The position where the anti - falling reinforcement bar 3 is anchored into the waist beam 2 is located outside the post - installed reinforcement bar 5 in the waist beam 2, and the welded reinforcement bar 4 is located inside the post - installed reinforcement bar 5 in the waist beam 2.

[0035] There is a waist beam reinforcement bar 7 on the outer side inside the waist beam 2. The upper, lower sides and the end side far from the overlapping pile 1 of the post - installed reinforcement bar 5 and the welded reinforcement bar 4 are all located inside the waist beam reinforcement bar 7. The steel bar section of the anti - falling reinforcement bar 3 that is anchored from the upper end of the waist beam 2 down to the bottom of the waist beam 2 is also located inside the waist beam reinforcement bar 7.

[0036] This application also provides a construction method for the connection structure between the large - cross - section waist beam 2 and the overlapping pile 1, including the following steps:

[0037] Determine the installation position of the waist beam 2 on the overlapping pile 1 according to the design elevation, drill holes at the installation position of the waist beam 2 on the overlapping pile 1, and install the post - installed reinforcement bar 5 in the drilled holes.

[0038] After the installation of the post - installed reinforcement bar 5 is completed, start to install the welded reinforcement bar 4, and weld one end of the welded reinforcement bar 4 to the main reinforcement bar of the overlapping pile 1.

[0039] After the installation of the welded reinforcement bar 4 is completed, start to install the waist beam reinforcement bar 7.

[0040] After the installation of the waist beam reinforcement bar 7 is completed, start to install the anti - falling reinforcement bar 3, and weld one end of the anti - falling reinforcement bar 3 to the pile body position of the overlapping pile 1 above the installation position of the waist beam 2, and anchor the other end of the anti - falling reinforcement bar 3 into the bottom waist beam reinforcement bar 7.

[0041] Carry out formwork installation and concrete pouring to form the waist beam 2 structure connected to the overlapping pile 1.

[0042] After the position of the waist beam 2 is obtained on the occlusal pile 1, the pile body of the occlusal pile 1 within the installation position range of the waist beam 2 is roughened, the protective layer of the main reinforcement 6 of the occlusal pile within the range is removed, and the surface is cleaned.

[0043] The installation position of the embedded reinforcement bar 5 is determined according to the position of the waist beam reinforcement bar 7; after drilling holes on the occlusal pile 1, glue is applied in the drilled holes, and then the embedded reinforcement bar 5 is installed.

[0044] Among them, when starting to install the waist beam steel bars 7, before the waist beam steel bars are tied, the foundation pit is excavated to a position ten centimeters from the bottom of the waist beam, and then a cushion layer is poured so that the waist beam steel bars 7 can fall on the cushion layer, and then the steel bars are installed, the formwork is supported, and the waist beam concrete is poured. Finally, after the waist beam strength meets the design requirements, excavation continues downward from the bottom of the waist beam to form a "suspended" effect.

[0045] The present invention is further described in detail below in conjunction with specific embodiments:

[0046] The siphon well of a certain project also serves as the starting well of the shield tunnel. The main plane is a regular rectangle. The siphon well enclosure structure is in the form of interlocking piles on the east, south and west sides, and the north side is open. The foundation pit size is 36.4m×42.8m, the foundation pit depth is 19.9m, and the enclosure structure uses 1000@650 interlocking piles plus three internal supports. The first support is 800mm×1000mm concrete support, the second support is Φ800mm, t=20mm steel support + 1000mm×1200mm concrete support, and the third support is Φ800mm, t=20mm steel support. The second and third supports are connected to the interlocking piles through a large-section waist beam of 1400mm×1200mm.

[0047] like Figure 1 , Figure 2 As shown, the connection structure between the waist beam 2 and the interlocking pile 1 is composed of welded steel bars 4, anti-falling steel bars 3, and embedded steel bars 5; during construction, the waist beam steel bars 7 are placed side by side with the interlocking pile 1 as a whole, and then the waist beam steel bars 7 and the interlocking pile 1 are connected in three forms of embedded steel bars 5, welded steel bars 4, and anti-falling steel bars 3, and finally the concrete is poured as a whole to achieve the overall effect; that is, the waist beam steel bars 7 are fixed on the interlocking pile as a whole by using embedded steel bars 5, welded steel bars 4, anti-falling steel bars 3 and waist beam steel bars 7 for mutual anchoring, and then the waist beam steel bars 7 are anchored and connected at the top and bottom respectively, and then the overall steel bars are installed with templates and concrete is poured.

[0048] Embedded steel bar 5 HRB400 grade steel bars are bent into an "L" shape, with two bars on the top and bottom. One end of the embedded steel bar 5 is embedded in the bite pile, the embedding depth is not less than 300mm, and one end is anchored into the waist beam. HRB400 grade steel bars are bent into Type, four on top and two on the bottom, one end of the welded steel bar 4 is welded to the main reinforcement of the bite pile, and the other end is anchored into the waist beam. HRB400 grade steel bars, one end of the anti-fall steel bar 3 is welded to the bite pile at the top of the waist beam, and the other end is anchored into the bottom of the waist beam. The specific method is as follows:

[0049] 1. According to the design elevation, place the waist beam 2 on the on-site bite pile 1, then roughen the bite pile 1 within the waist beam 2, remove the protective layer of the bite pile main reinforcement 6, and clean its surface;

[0050] 2. Place the installation position of the embedded steel bar 5 within the range of the waist beam 2 according to the position of the waist beam steel bar 7, then drill holes, and finally glue the holes to install the embedded steel bar 5;

[0051] 3. After the implanted steel bars 5 are installed, the welding steel bars 4 are started. After all the welded steel bars 4 are welded, the waist beam steel bars 7 are installed;

[0052] 4. After the installation of the waist beam reinforcement 7 is completed, start installing the anti-fall reinforcement 3. Anchor the anti-fall reinforcement 3 into the bottom waist beam reinforcement 7, and weld the top to the main reinforcement 6 of the bite pile. After all the reinforcement installation and acceptance are completed, install the template and pour concrete.

[0053] The welding quality between the above-mentioned steel bars must meet the welding requirements, including weld length, weld height, etc. The weld length used is not less than 10d for single-sided welding and not less than 5d for double-sided welding; where d refers to the diameter of the welded steel bar, such as 5d refers to 5 times the diameter of the welded steel bar.

[0054] The positioning, layout, verticality and elevation of all steel bars meet the design requirements.

[0055] The embedding depth, amount of embedding glue, drilling diameter and hole cleaning of the embedded steel bar 5 all meet the embedding requirements.

[0056] The length of the ends of the embedded steel bars 5, welded steel bars 4 and anti-falling steel bars 3 anchored in the waist beam 2 is set according to the different steel bar diameters of the anti-falling steel bars used. The larger the steel bar diameter, the longer the anchoring length.

[0057] When welding the main reinforcement 6 of the occlusal pile, the surface stirrups of the occlusal pile 1 need to be divided, and the stirrups need to be restored after the welding is completed, and the auxiliary bar welding is used for the restoration.

[0058] The connection combination method is an important factor in determining whether the foundation pit support structure is safe and reliable. The connection combination method adopted in this application can fundamentally solve this problem. It is suitable for semi-enclosed deep foundation pit excavation and support projects with complex surrounding environments and limited sites. It is also suitable for some large-section waist beams and surrounding structure connection projects. It can effectively improve the connection strength between the waist beams and the bite piles, reduce the number of steel supports, reduce the difficulty of internal support construction, and shorten the construction period.

[0059] The structural system of the present application is simple to construct, flexible and convenient to use, simple to operate, saves time and effort, and has high practicability for the construction of foundation pit support structures.

[0060] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any technician familiar with the profession, without departing from the scope of the technical solution of the present invention and based on the technical essence of the present invention, may make any simple modifications, equivalent substitutions and improvements to the above embodiments, which are still within the protection scope of the technical solution of the present invention.

Claims

1. A connection structure between a large-section waist beam and an interlocking pile, characterized in that: The waist beam is fixed on the secant pile through a connecting structure, and the connecting structure includes anti-falling steel bars, welded steel bars and post-inserted steel bars; One end of the anti-falling steel bar is welded to the pile body of the secant pile above the waist beam, and the other end of the anti-falling steel bar is anchored from the upper end of the position where the waist beam is away from the secant pile down to the bottom of the waist beam; The post-inserted steel bar is L-shaped. One end of the post-inserted steel bar is anchored into the waist beam, and the other end of the post-inserted steel bar is implanted into the pile body of the secant pile corresponding to the installation position of the waist beam; The post-inserted steel bar includes an upper post-inserted steel bar and a lower post-inserted steel bar. The inner angle of the L shape of the upper post-inserted steel bar corresponds to the upper inner angle of the position where the waist beam is away from the secant pile, and the inner angle of the L shape of the lower post-inserted steel bar corresponds to the lower inner angle of the position where the waist beam is away from the secant pile; The welded steel bar is C-shaped. One end of the welded steel bar is welded to the main reinforcement of the secant pile, and the other end of the welded steel bar is anchored into the waist beam; The welded steel bar includes an upper welded steel bar arranged on the upper part of the waist beam and a lower welded steel bar arranged on the lower part of the waist beam. The opening of the C shape of the upper welded steel bar faces downwards, and the opening of the C shape of the lower welded steel bar faces upwards.

2. The connection structure of the large-section waist beam and the bite pile according to claim 1 is characterized in that: The welding position of the anti-falling steel bar on the secant pile is on the side of the secant pile close to the waist beam.

3. The connection structure of the large-section waist beam and the bite pile according to claim 1 is characterized in that: The position where the anti-falling steel bar is anchored into the waist beam is located outside the post-inserted steel bar in the waist beam, and the welded steel bar is located inside the post-inserted steel bar in the waist beam.

4. The connection structure of the large-section waist beam and the bite pile according to claim 1 is characterized in that: There are waist beam steel bars located inside the circumferential wall of the waist beam in the waist beam. The upper, lower sides and the end side away from the secant pile of the post-inserted steel bar and the welded steel bar are all located inside the waist beam steel bars; The steel bar section of the anti-falling steel bar anchored from the upper end of the waist beam down to the bottom of the waist beam is also located inside the waist beam steel bars.

5. The connection structure of the large-section waist beam and the bite pile according to claim 1 is characterized in that: For each upper post-inserted steel bar and lower post-inserted steel bar corresponding to one waist beam, two are set. Four upper welded steel bars are set and two lower welded steel bars are set.

6. The construction method of the connection structure of the large-section waist beam and the occlusal pile according to any one of claims 1 to 5, characterized in that: Including the following steps: Determine the installation position of the waist beam on the secant pile according to the design elevation, drill holes at the installation position of the waist beam on the secant pile, and install post-inserted steel bars in the drilled holes; After the installation of the post-inserted steel bars is completed, install the welded steel bars so that one end of the welded steel bars is welded to the main reinforcement of the secant pile; After the installation of the welded steel bars is completed, install the waist beam steel bars; After the installation of the waist beam steel bars is completed, install the anti-falling steel bars so that one end of the anti-falling steel bars is welded to the pile body position of the secant pile above the installation position of the waist beam, and the other end of the anti-falling steel bars is anchored into the waist beam steel bars at the bottom; Carry out formwork installation and concrete pouring to form a waist beam structure connected to the secant pile.

7. The connection structure of the large-section waist beam and the bite pile according to claim 6, characterized in that: After determining the waist beam position on the secant pile, roughen the pile body of the secant pile within the range of the waist beam installation position, remove the main reinforcement protection layer of the secant pile within this range, and clean its surface.

8. The connection structure of the large-section waist beam and the bite pile according to claim 6, characterized in that: Determine the installation position of the post-inserted steel bars according to the position of the waist beam steel bars.

9. The connection structure of the large-section waist beam and the bite pile according to claim 6, characterized in that: When installing the post-inserted steel bars, after drilling holes on the secant pile, apply glue in the drilled holes, and then install the post-inserted steel bars.

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