WO2021042764A1 - 混凝土变截面预制方桩 - Google Patents

混凝土变截面预制方桩 Download PDF

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Publication number
WO2021042764A1
WO2021042764A1 PCT/CN2020/091175 CN2020091175W WO2021042764A1 WO 2021042764 A1 WO2021042764 A1 WO 2021042764A1 CN 2020091175 W CN2020091175 W CN 2020091175W WO 2021042764 A1 WO2021042764 A1 WO 2021042764A1
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WIPO (PCT)
Prior art keywords
section
pile
cross
variable cross
transition surface
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PCT/CN2020/091175
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English (en)
French (fr)
Inventor
周兆弟
Original Assignee
周兆弟
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Filing date
Publication date
Application filed by 周兆弟 filed Critical 周兆弟
Priority to BR112022003986A priority Critical patent/BR112022003986A2/pt
Priority to JP2022513600A priority patent/JP7223474B2/ja
Priority to AU2020341600A priority patent/AU2020341600B2/en
Priority to KR1020227010291A priority patent/KR102636911B1/ko
Priority to EP20860285.4A priority patent/EP4026950A4/en
Priority to US17/639,882 priority patent/US20220341117A1/en
Priority to CA3153609A priority patent/CA3153609A1/en
Publication of WO2021042764A1 publication Critical patent/WO2021042764A1/zh

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    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E04C5/06—Reinforcing elements of metal, e.g. with non-structural coatings of high bending resistance, i.e. of essentially three-dimensional extent, e.g. lattice girders
    • E04C5/0604—Prismatic or cylindrical reinforcement cages composed of longitudinal bars and open or closed stirrup rods
    • E04C5/0618—Closed cages with spiral- or coil-shaped stirrup rod
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22—Piles
    • E02D5/48—Piles varying in construction along their length, i.e. along the body between head and shoe, e.g. made of different materials along their length
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22—Piles
    • E02D5/24—Prefabricated piles
    • E02D5/30—Prefabricated piles made of concrete or reinforced concrete or made of steel and concrete
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22—Piles
    • E02D5/52—Piles composed of separable parts, e.g. telescopic tubes ; Piles composed of segments
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22—Piles
    • E02D5/52—Piles composed of separable parts, e.g. telescopic tubes ; Piles composed of segments
    • E02D5/523—Piles composed of separable parts, e.g. telescopic tubes ; Piles composed of segments composed of segments
    • E02D5/526—Connection means between pile segments
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E04C5/06—Reinforcing elements of metal, e.g. with non-structural coatings of high bending resistance, i.e. of essentially three-dimensional extent, e.g. lattice girders
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E04C5/06—Reinforcing elements of metal, e.g. with non-structural coatings of high bending resistance, i.e. of essentially three-dimensional extent, e.g. lattice girders
    • E04C5/0604—Prismatic or cylindrical reinforcement cages composed of longitudinal bars and open or closed stirrup rods
    • E04C5/0609—Closed cages composed of two or more coacting cage parts, e.g. transversally hinged or nested parts
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2200/00—Geometrical or physical properties
    • E02D2200/16—Shapes
    • E02D2200/1628—Shapes rectangular
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2300/00—Materials
    • E02D2300/0004—Synthetics
    • E02D2300/0018—Cement used as binder
    • E02D2300/002—Concrete

Definitions

  • the invention relates to the technical field of concrete prefabricated piles, in particular to concrete variable cross-section prefabricated square piles.
  • Concrete precast piles are prefabricated concrete components with steel cages inside prefabricated in the factory.
  • Prefabricated piles include straight piles and variable-section piles.
  • the cross-sectional shape and size of the vertical pile body in the length direction are the same, while the cross-sectional size and shape of the variable-section pile body will change along the length of the pile.
  • variable cross-section piles have better pull resistance and bearing performance, and are more and more favored by the construction industry.
  • CN 204738291 U discloses a precast concrete bamboo-jointed solid square pile, which includes a pile body with a square section of the pile body, and includes two large section sections located at the upper end of the pile body and the lower end of the pile body, and two The middle section between the large section segments; both ends of the middle section are provided with small section sections, and the section area of the large section section is larger than that of the small section section; the large section section and The transition between the small cross-section segments is through an inclined plane.
  • This kind of square pile has multiple comprehensive properties including high vertical bearing capacity, strong horizontal shear resistance, good corrosion resistance, and strong pull resistance.
  • the purpose of the present invention is to provide a variable cross-section concrete precast square pile to reduce the easy damage of the middle section, reduce the damage rate of the variable cross-section precast square pile, and make the product quality of the variable cross-section precast square pile more stable and reliable, and thus better To meet the requirements of actual use.
  • the present invention provides a concrete variable cross-section precast pile, comprising a pile body with large and small sections alternately arranged in the longitudinal direction, the cross sections of the large section and the small section are generally rectangular; A lateral transition surface is formed between the side surfaces of the large cross-sectional section and the adjacent small cross-sectional section; at least a part of the lateral transition surfaces have front edges that deviate from the vertical in the lateral projection and/ Or the back edge, and the vertical projection of the intersection line of the lateral transition surface and the first horizontal plane is located outside the vertical projection of the intersection line of the lateral transition surface and the second horizontal plane; the first horizontal planes are any two A horizontal plane located above in the horizontal plane, the second horizontal plane is a horizontal plane located below in any two horizontal planes, one or two side surfaces of the small section section are perpendicular to the bottom surface of the small section section or from top to bottom The inner side of the pile is inclined to set the angle.
  • the front edge and/or the back edge of the lateral transition surface deviating from the vertical direction in the lateral projection are inclined edges or curved edges.
  • the front edge and the rear edge of the side surface of the large cross-section section located between the two ends are vertical edges, and the surface width thereof remains constant from top to bottom; or, the large cross-section located between the two ends.
  • the front edge and/or the back edge of the side surface of the segment deviate from the vertical direction in the lateral projection, and its surface width becomes larger or smaller from top to bottom.
  • the lateral transition surface includes a first transition surface located at the front of the small section section and a second transition surface located at the rear of the small section section, and the rear edge of the first transition surface is inclined forward from top to bottom Or curved; and/or, the front edge of the second transition surface is inclined or curved from top to bottom.
  • the lateral transition surface includes a first transition surface located at the front of the small section section and a second transition surface located at the rear of the small section section, and the front edge of the first transition surface is inclined forward from top to bottom Or curved; and/or, the rear edge of the second transition surface is inclined or curved from top to bottom.
  • the lateral transition surface is a flat surface, the front edge of which is parallel to the rear edge, and the surface width remains constant from top to bottom, or the lateral transition surface is a flat surface, and the front edge and the back edge of the surface are not parallel.
  • the width becomes larger or smaller from top to bottom; or,
  • the lateral transition surface is a curved surface, the front edge is parallel to the rear edge, and the surface width remains constant from top to bottom, or the lateral transition surface is a curved surface, and the front edge and the back edge are not parallel, and the surface width is from the top And the bottom becomes larger or smaller.
  • the lateral transition surface is a concave curved surface, a convex curved surface or a twisted surface.
  • the concave curved surface includes a concave curved surface or a concave tapered surface
  • the convex curved surface includes a convex curved surface or a convex tapered surface
  • the extension line of the vertical projection of the intersection line of the lateral transition surface and the first horizontal plane intersects the extension line of the vertical projection of the intersection line of the lateral transition surface and the second horizontal plane.
  • the pile body has a pile end surface, at least one pile end surface has a groove and a plurality of spaced connection holes, the groove is used to at least partially contain the storage block storing the viscous substance, and the groove depth is less than The initial height of the storage block, when the prefabricated square piles are butted, compressing the storage block can release the viscous material to eliminate and/or fill the gap between the pile end faces of the opposing prefabricated square piles.
  • the groove depth of the accommodating groove is greater than or equal to 1 mm
  • the groove width is greater than or equal to 1 mm
  • the accommodating groove is more than 0.5 cm from the connecting hole.
  • the groove depth of the containing groove is 2mm-20mm.
  • At least one of the grooves is circular or annular or rectangular or regular polygonal and is located at the center of the end face of the pile;
  • At least one of the grooves is ring-shaped and surrounds all connecting holes
  • At least one of the grooves is ring-shaped and surrounds part of the connecting hole
  • At least one of the grooves is ring-shaped and surrounds a single connecting hole.
  • the rigid skeleton includes: a main reinforcement skeleton arranged with a plurality of main reinforcements at intervals and surrounded by a reserved cavity, and a skeleton stirrup for tightening the main reinforcement skeleton;
  • the end of the main reinforcement skeleton is sheathed with a rigid mesh cover and/or rigid mesh to strengthen the structural strength of the precast pile, the end of the main reinforcement skeleton is fastened and fixed by auxiliary stirrups, and the winding spacing of the auxiliary stirrups is less than or equal to The winding spacing of the skeleton stirrups.
  • the auxiliary stirrups form a stirrup densification zone, the length of the stirrup densification zone is greater than the length of the end large cross-section section; the winding density of the stirrup densification zone is 1.5-3 times that of the non-densification zone.
  • the end face of the main rib skeleton is also provided with a number of C-shaped hoops with openings toward the middle of the reserved cavity.
  • a connecting nut is connected to the end of the main rib, and the auxiliary stirrup is connected to fix at least one of the connecting nuts.
  • the C-shaped hoop is arranged in the reserved cavity of the main reinforcement skeleton in a horizontal or longitudinal order; and/or, the C-shaped hoop is intersectedly arranged in the reserved cavity of the main reinforcement skeleton; the C-shaped The hoop is fixedly connected with the auxiliary stirrup or/and the rigid net cover.
  • the auxiliary stirrup and the rigid mesh cover are connected and fixed, and the rigid mesh cover is located inside the auxiliary stirrup;
  • the rigid mesh cover includes a plurality of ring ribs arranged at intervals along the length of the main rib skeleton and a plurality of axial ribs connecting and fixing the ring ribs, wherein the axial ribs are parallel to the main ribs;
  • the rigid mesh is arranged at the end of the main rib skeleton and arranged at intervals along the length direction of the reserved cavity.
  • the length of the large cross section at both ends of the pile is greater than the length of the large cross section of the middle part, and the length of the large cross section at both ends of the pile is about 2 to 6 times the length of the large cross section of the middle part;
  • the cross section area of the small section section is S1
  • the total cross section area of the steel rod is S2
  • the ratio of S2 to S1 is at least 0.5% to 0.15%.
  • the present invention adopts the above structural design, and enhances the strength of the top surface and lateral transition surface of the variable cross-section prefabricated square pile, so that the compressive strength of the top surface of the variable cross-section prefabricated square pile is increased while the bottom surface is lifted.
  • the tensile force is reduced, the effect of improving the bending performance of the variable cross-section precast square pile is realized, the occurrence of cracks during the lifting of the variable cross-section precast square pile is reduced, the quality of the pile body is improved, and the rejection rate of waste piles is reduced.
  • the front edge and/or the rear edge of the lateral transition surface deviate from the vertical direction in the lateral projection, the area of the lateral transition surface is increased, the side friction resistance coefficient is changed, and the variable cross-section prefabricated square pile is improved.
  • the side friction resistance and compression and pull resistance of the pile body can reduce the size of the precast pile under the same working conditions, improve the cost performance, and comply with the national energy saving and emission reduction policy.
  • variable cross-section prefabricated square piles can also improve the demoulding efficiency during the production of variable cross-section prefabricated square piles, and improve the quality of the pile body.
  • the pre-stressed tension can be released, which can effectively prevent the protruding part of the mold from being locked at the variable cross-section, can reduce the damage of the variable cross-section prefabricated square pile bamboo joint, and reduce the manual consumption of manual repairing damage.
  • the integrity of the pile body is good, and the pile body strength is high.
  • Figure 1 is a schematic structural diagram of a variable cross-section prefabricated square pile disclosed in the first embodiment of the present invention
  • Figure 2 is a schematic structural diagram of the variable cross-section prefabricated square pile shown in Figure 1 from another perspective;
  • Figure 3 is a top view of the variable cross-section prefabricated square pile shown in Figure 1;
  • Figure 4 is a partial enlarged view of part A in Figure 3;
  • Figure 5 is a top view of the variable cross-section prefabricated square pile disclosed in the second embodiment of the present invention.
  • Fig. 6 is a partial enlarged view of part B in Fig. 5;
  • Figure 7 is a partial enlarged view of the variable cross-section prefabricated square pile disclosed in the third embodiment of the present invention.
  • Figure 8 is a partial enlarged view of the variable cross-section prefabricated square pile disclosed in the fourth embodiment of the present invention.
  • FIG. 9 is a schematic structural diagram of a variable cross-section prefabricated square pile disclosed in the fifth embodiment of the present invention.
  • Figure 10 is a top view of the variable cross-section prefabricated square pile shown in Figure 9;
  • FIG. 11 is a schematic structural diagram of a variable cross-section prefabricated square pile disclosed in the sixth embodiment of the present invention.
  • FIG. 12 is a schematic structural diagram of a variable cross-section prefabricated square pile disclosed in the seventh embodiment of the present invention.
  • FIG. 13 is a schematic structural diagram of a variable cross-section prefabricated square pile disclosed in the eighth embodiment of the present invention.
  • Figure 14 is a partial enlarged view of Figure 13;
  • Figure 15 is a bottom view of Figure 14;
  • Figure 16 is a side view of the variable cross-section prefabricated square pile shown in Figure 13;
  • Figure 17 is a schematic diagram of the end of the variable cross-section prefabricated square pile shown in Figure 13 with a chamfered bottom edge;
  • Figure 18 is a partial structural schematic diagram of the bottom edge of the variable cross-section prefabricated square pile shown in Figure 13 with chamfers;
  • FIG. 19 is a schematic diagram of the end of the smooth transition of the top edge of the variable cross-section prefabricated square pile shown in FIG. 13;
  • Figure 20 is a partial structural schematic diagram of the smooth transition of the bottom edge of the variable cross-section prefabricated square pile shown in Figure 13;
  • Fig. 21 is a schematic diagram of the ends of the top and bottom edges of the variable cross-section prefabricated square pile shown in Fig. 13 with chamfered corners;
  • Figure 22 is a partial structural schematic diagram of the top and bottom edges of the variable cross-section prefabricated square pile shown in Figure 13 with chamfered corners;
  • Fig. 23 is a schematic diagram of the end of the variable cross-section prefabricated square pile shown in Fig. 13 with a chamfer at the top edge and a smooth transition at the bottom edge;
  • Fig. 24 is a partial structural diagram of the prefabricated square pile with variable cross-section shown in Fig. 13 with a chamfer at the top edge and a smooth transition at the bottom edge;
  • 25 is a schematic diagram of the structure of the variable cross-section prefabricated square pile disclosed in the ninth embodiment of the present invention.
  • Fig. 26 is a schematic structural diagram of a variable cross-section prefabricated square pile disclosed in the tenth embodiment of the present invention.
  • Figure 27 is a schematic structural diagram of a variable cross-section prefabricated square pile disclosed in the eleventh embodiment of the present invention.
  • Figure 28 is a side view of the variable cross-section prefabricated square pile shown in Figure 27;
  • Figure 29 is a bottom view of the variable cross-section prefabricated square pile shown in Figure 27;
  • Figure 30 is a partial enlarged view of part C in Figure 29;
  • Figure 31 is a schematic diagram of the concentrated display of the lateral transition surfaces of types (a) to (g) formed on the pile body;
  • Figure 32 is a schematic diagram of concentrated display of (h) ⁇ (n) type lateral transition surfaces formed on the pile body;
  • Figure 33 is a schematic diagram of concentrated display of (o) ⁇ (u) type lateral transition surfaces formed on the pile body;
  • Figure 34 is a schematic diagram of concentrated display of (v) ⁇ (w) types of lateral transition surfaces formed on the pile body;
  • Figure 35 is a partial structural diagram of the symmetrical front side transition surface and rear side transition surface of the same large cross-sectional section;
  • 36 is a schematic diagram of the installation structure of the variable cross-section prefabricated square pile disclosed in the twelfth embodiment of the present invention.
  • Fig. 37 is a schematic diagram of the position and shape of the groove on the end face of the precast pile in Fig. 36;
  • Fig. 38 is another schematic diagram of the position and shape of the groove on the end face of the precast pile in Fig. 36;
  • Figure 39 is another schematic diagram of the position and shape of the groove on the end face of the precast pile in Figure 36;
  • Fig. 40 is another schematic diagram of the position and shape of the groove on the end face of the precast pile in Fig. 36;
  • 41 is a schematic diagram of the pile connection process of the variable cross-section prefabricated square pile disclosed in the thirteenth embodiment of the present invention.
  • Figure 42 is a schematic diagram of the completed state of connecting the variable cross-section prefabricated square piles in Figure 41;
  • 43 is a schematic diagram of the connecting structure of the variable cross-section prefabricated square pile disclosed in the fourteenth embodiment of the present invention.
  • Figure 44 is a schematic diagram of the completed state of connecting the variable cross-section prefabricated square piles in Figure 43;
  • Figure 45 is an enlarged view of the structure at D in Figure 43;
  • FIG. 46 is a schematic structural diagram of the rigid skeleton of the variable cross-section prefabricated square pile disclosed in the fifteenth embodiment of the present invention.
  • Figure 47 is an end view of the rigid frame shown in Figure 46;
  • Figure 49 is an end view of the rigid frame shown in Figure 48;
  • 50 is a schematic structural diagram of the rigid framework of the variable cross-section prefabricated square pile disclosed in the seventeenth embodiment of the present invention.
  • Figure 51 is an end view of the rigid frame shown in Figure 50;
  • variable cross-section prefabricated square pile disclosed in the eighteenth embodiment of the present invention.
  • Figure 53 is an end view of the rigid frame shown in Figure 52;
  • Figure 54 is a schematic diagram of the structure of a rigid mesh
  • Figure 55 is a schematic diagram of the structure of auxiliary stirrups
  • Figure 56 is a schematic diagram of the structure of the rigid net cover
  • Figure 57 is a schematic diagram of the structure of the C-type ferrule.
  • Pile body Small section section 2-1. Upper edge 2-2. Lower edge 3. Large section section 3-1. Upper edge 3-2. Lower edge 4. Lateral transition surface 4-1. First Transition surface 4-1-1. Front edge 4-1-2. Back edge 4-2. Second transition surface 4-2-1. Front edge 4-2-2. Back edge 4-2-3. Upper edge 4-2-4. Lower edge 5. Left protrusion 6. Right protrusion 7. Upper protrusion 8. Lower protrusion 9. Connection hole 10. Storage block 11. Groove 12. Sticky substance 13. Rebar 14. Mechanical connection 15. Seal ring 16. Concrete member 17. Pile end 18. Smooth transition 19. Pile end surface 21. Main reinforcement 22. Skeleton stirrup 23. Rigid mesh 23-1. Reinforcing bar 24. Auxiliary Stirrup 25. Connecting nut 26. Rigid mesh cover 26-1. Ring reinforcement 26-2. Axial reinforcement 27. C-type hoop
  • precast piles The construction procedures of precast piles are mainly divided into precasting, transportation, stacking, and pile sinking. In each construction procedure, it is difficult to avoid frequent lifting of precast piles.
  • the existing lifting method is to set a hook on the top of the pile body, and use the lifting equipment to lift the precast pile.
  • two hooks are set on the pile for two-point lifting.
  • the bottom surface and lateral transition surface of the pile body are very prone to cracks due to the high tensile strength. This is the cause of the pile.
  • the present invention further improves the structure of the variable cross-section prefabricated square pile to improve or eliminate the above-mentioned technical problems of the variable cross-section prefabricated square pile to a certain extent.
  • Figure 1 is a structural schematic diagram of the variable cross-section prefabricated square pile disclosed in the first embodiment of the present invention
  • Figure 2 is a structural schematic diagram of the variable cross-section prefabricated square pile shown in Figure 1 from another perspective
  • 3 is a top view of the variable cross-section prefabricated square pile shown in Fig. 1
  • Fig. 4 is a partial enlarged view of part A in Fig. 3.
  • variable cross-section concrete precast pile provided by the present invention has four small section sections 2 and three large section sections 3 arranged alternately along the front and rear direction of the pile body 1.
  • the large section section The cross-sections of 3 and small section section 2 are generally rectangular, the top, right side and bottom surface of the pile are flat, and the left side is concave and convex.
  • the left side of each large section section 3 is relative to the small section section 2.
  • Protruding outward, a lateral transition surface 4 is formed between each small section section 2 and the left protrusion 5.
  • the lateral transition surface 3 formed between the small section section 2 and the front large section section 3 is the first transition surface 4-1
  • the lateral transition surface formed between the rear large section section 3 is The second transition surface 4-2.
  • the first transition surface 4-1 is an inclined plane
  • the front edge 4-1-1 and the rear edge 4-1-2 are straight edges, and the two are parallel to each other, and the front edge 4-1-1 and the rear edge 4- 1-2 all deviate from the vertical direction in the lateral projection, and incline forward at a certain angle from top to bottom.
  • intersection line between any two horizontal planes and the first transition surface 4-1 is vertical projection
  • the vertical projection L1 of the intersection line between the first transition surface 4-1 and the first horizontal plane Located outside the vertical projection L2 of the line of intersection between the first transition surface 4-1 and the second horizontal plane, where the first horizontal plane 4-1 is the upper horizontal plane of any two horizontal planes, and the second horizontal plane is any two horizontal planes
  • the middle is located below the horizontal plane.
  • the second transition surface 4-2 is an oblique plane
  • the front edge 4-2-1 and the back edge 4-2-2 are straight edges, and the two are parallel to each other, and the front edge 4-2-1 and the back edge 4 -2-2 Maintain the vertical orientation on the side projection, and do not tilt forward or backward.
  • variable cross-section prefabricated square pile with this structure can enhance the strength of the top surface and the lateral transition surface 4, so that the compressive strength of the top surface of the variable cross-section prefabricated square pile during lifting is increased, while the pulling force on the bottom surface is reduced, which improves
  • the effect of the bending performance of the variable-section prefabricated square piles reduces the occurrence of cracks when the variable-section prefabricated square piles are lifted, improves the quality of the pile body, and reduces the rejection rate of the waste piles.
  • the front edge 4-1-1 and the rear edge 4-1-2 of the first transition surface 4-1 deviate from the vertical direction in the lateral projection, the area of the first transition surface 4-1 is increased, and the area of the first transition surface 4-1 is increased.
  • the side friction resistance coefficient is improved, thereby improving the side friction resistance and compressive and uplift performance of the variable cross-section prefabricated square pile. Under the same working conditions, the prefabricated pile specifications can be reduced, the cost performance can be improved, and the national energy saving and emission reduction requirements can be reduced. policy.
  • variable cross-section prefabricated square piles can also improve the demoulding efficiency during the production of variable cross-section prefabricated square piles and improve the quality of the pile body.
  • the pre-stressed tension can be released, which can effectively prevent the protruding part of the mold from being locked at the variable cross-section, can reduce the damage of the variable cross-section precast square pile bamboo joint, and reduce the manual consumption of manual repairing damage
  • the integrity of the pile body is good, and the pile body strength is high.
  • FIG. 5 is a top view of the variable cross-section prefabricated square pile disclosed in the second embodiment of the present invention
  • FIG. 6 is a partial enlarged view of part B in FIG. 5.
  • the left side surface and the right side surface of the small cross-section section 2 are not perpendicular to the bottom surface. Instead, they are inclined at a set angle from top to bottom toward the inside of the pile.
  • the large section section 3 The left and right surfaces of the slab are also not perpendicular to the bottom surface, instead, they are inclined to set an angle from top to bottom toward the inside of the pile.
  • the upper edge 2-1 and the lower edge 2-2 of the small section 2 no longer overlap, and the vertical projection of the lower edge 2-2 is located at the vertical projection of the upper edge 2-1
  • the upper edge 3-1 and the lower edge 3-2 of the large section section 3 no longer overlap, and the vertical projection of the lower edge 3-2 is located in the vertical direction of the upper edge 3-1 The inside of the projection.
  • two front-to-rear symmetrical lateral transition surfaces 4 can be formed on the same left protrusion 5, or on the same left protrusion 5 as the basis of the second embodiment.
  • the part 5 is formed with two symmetrical lateral transition surfaces 4 (see FIG. 8), thereby obtaining third, fourth and more embodiments.
  • FIG. 9 is a schematic diagram of the structure of the variable cross-section precast square pile disclosed in the fifth embodiment of the present invention
  • FIG. 10 is a top view of the variable cross-section precast square pile shown in FIG. 9.
  • the right side of the pile 1 is also provided with three right protrusions 6 protruding from the pile at intervals, and the protrusions 5 on the left side of the pile 1 and The protrusion 6 on the right side is mirror-symmetrical.
  • the left convex part 5 and the right convex part 6 are mirror-symmetrical, so that when the variable cross-section prefabricated square pile enters the soil, the force of the pile body can be more uniform, so that the pile body can enter the soil body in a vertical state.
  • FIG. 11 is a schematic structural diagram of a variable cross-section prefabricated square pile disclosed in a sixth embodiment of the present invention.
  • large cross-section sections 3 are formed at both ends of the pile body 1, and the cross-sections of the large cross-section sections 3 at both ends are basically the same as the cross-sections of the large cross-section section 3 in the middle.
  • This structural design can effectively improve the pile end bearing capacity of the pile body, and at the same time improve the pile end's anti-driving capacity, and can balance the pile end bearing capacity, pile pressure, and side friction resistance in an optimal situation.
  • this embodiment can not only receive uniform force during pile driving, ensure vertical entry into the soil, but also effectively improve the bearing capacity of the pile section.
  • FIG. 12 is a schematic structural diagram of a variable cross-section prefabricated square pile disclosed in a seventh embodiment of the present invention.
  • the top surface of the pile body 1 is provided with three upper protrusions 7 protruding from the pile body, and the bottom surface of the pile body 1 is provided with three lower protrusions protruding from the pile body. Protruding portion 8.
  • variable cross-section prefabricated square pile of this embodiment has an upper protrusion 7 and a lower protrusion 8, which further improves the bending strength of the pile body.
  • the contact area with the soil is further increased, and the side friction resistance is improved.
  • the left convex portion 5, the right convex portion 6 and the lower convex portion 8, the left convex portion 5 and the right convex portion are uniformly transitioned, which is easy to manufacture, has a compact structure and good mechanical properties.
  • each protrusion form a closed loop, which strengthens the integrity of the variable cross-section prefabricated square pile, and also achieves the optimal bending performance of the pile body, and the strength of the protrusion It has been strengthened to a certain extent, and the ability to resist crushing is further improved.
  • Figure 13 is a structural diagram of the variable cross-section prefabricated square pile disclosed in the eighth embodiment of the present invention.
  • Figure 14 is a partial enlarged view of Figure 13;
  • Figure 15 is a bottom view of Figure 14;
  • Figure 13 shows the side view of the variable cross-section prefabricated square pile.
  • large cross-section sections 3 are formed at both ends of the pile body 1, and the cross-sections of the large cross-section sections 3 at both ends are basically the same as the cross-sections of the large cross-section section 3 in the middle.
  • Relative to the small cross-section section 2 there are a left protrusion 5, a right protrusion 6, an upper protrusion 7 and a lower protrusion 8 in the circumferential direction.
  • This structural design can effectively increase the pile end bearing capacity of the pile body, and at the same time improve the pile end's anti-strike ability, and can balance the pile end bearing capacity, pile pressure, and side friction resistance in an optimal situation.
  • the length of the large section section 3 at both ends of the pile body 1 is greater than the length of the large section section 3 in the middle part.
  • the length of the large section section 3 at both ends of the pile is approximately 2 to 6 times the length of the large section section 3 in the middle part to increase the pile end. Structural strength and impact resistance.
  • this embodiment can not only receive uniform force during pile driving, ensure vertical entry into the soil, but also effectively improve the bearing capacity of the pile section.
  • more embodiments can be obtained by changing the shape of the upper and lower edges of the large cross-sectional section 3 of the pile body.
  • the bottom edge of the variable cross-section prefabricated square pile has a beveled chamfer (see Figure 17, Figure 18), or the top edge of the variable cross-section precast square pile has a smooth transition, that is, rounded corners (see Figure 19, Figure 20), or,
  • the top and bottom edges of the variable cross-section prefabricated square piles are both chamfered (see Figure 21, Figure 22), or, the top edge of the variable cross-section prefabricated square pile has beveled chamfers, and the bottom edge is smoothly transitioned (see Figure 23, Figure 22). twenty four).
  • the large cross-section section 3 in the middle part is omitted, and only the large cross-section section 3 at the two ends is retained, and the length of the pile body is shortened at the same time, the following can be obtained:
  • the embodiment shown in FIG. 25, or only one large cross-section section 3 in the middle part is retained, so as to obtain the embodiment shown in FIG. 26, and on the basis of FIGS. 25 and 26, the large cross-section section 3
  • Other embodiments are obtained by adding the upper protrusion 7 and the lower protrusion 8.
  • the length of the pile body 1 in these embodiments is relatively short, it can be connected to each other to form a longer-sized precast pile by butting a plurality of pile bodies 1, thereby achieving basically the same use effect as the other embodiments described above.
  • Figure 27 is a schematic structural diagram of the variable cross-section prefabricated square pile disclosed in the eleventh embodiment of the present invention
  • Figure 28 is a side view of the variable cross-section prefabricated square pile shown in Figure 27
  • Figure 29 is Figure 27 The bottom view of the variable cross-section prefabricated square pile is shown
  • FIG. 30 is a partial enlarged view of part C in FIG. 29.
  • the lateral transition surfaces 4 of the two small cross-section sections 2 are symmetrical in the front-to-rear direction.
  • the transition surface 4 will be described.
  • This small section 2 has a first transition surface 4-1 at the front and a second transition surface 4-2 at the rear, wherein the front edge 4-1-1 and the rear edge of the first transition surface 4-1 4-1-2 is parallel and inclined from top to bottom forward; the front edge of the second transition surface 4-2 4-2-1 slopes from top to bottom, and the rear edge of the second transition surface 4-2 4-2-2 Tilt forward from top to bottom, the two are not parallel, and the lateral projection of the two forms a trapezoid waistline with a large upper and a smaller one.
  • the vertical projection of the upper edge 4-2-3 of the second transition surface 4-2 is located outside the vertical projection of the lower edge 4-2-4 of the second transition surface 4-2. If the intersection line between any two horizontal planes and the second transition surface 4-2 is vertically projected, the vertical projection of the intersection line between the second transition surface 4-2 and the first horizontal plane will be located on the second transition surface 4- 2 The outside of the vertical projection of the line of intersection with the second horizontal plane, where the first horizontal plane is the horizontal plane above any two horizontal planes, the second horizontal plane is the horizontal plane below any two horizontal planes, and the second transition The extension line of the vertical projection of the intersection line of the surface 4-2 and the first horizontal plane and the extension line of the vertical projection of the intersection line of the second transition surface 4-2 and the second horizontal plane intersect at a point.
  • FIG. 31 is a schematic diagram of a concentrated display of the lateral transition surfaces of types (a) to (g) formed on the pile body.
  • the lateral transition surface 4 of the small section 2 can also have various forms.
  • the first transition surface 4-1 of the lateral transition surface 4 of type (a) shown in the figure is a flat surface, and its front edge 4-1-1 and rear edge 4-1-2 are parallel, when viewed from the side , The width between the front edge 4-1-1 and the rear edge 4-1-2 remains constant, which has been described in the previous embodiment.
  • the first transition surface 4-1 of the lateral transition surface 4 of type (b) shown in the figure is a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined forward from top to bottom, and the rear edge The lateral projection of 4-1-2 is inclined from top to bottom to back. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually increases from top to bottom.
  • the first transition surface 4-1 of the lateral transition surface 4 of type (c) shown in the figure is a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined forward from top to bottom, and the rear edge The lateral projection of 4-1-2 remains vertical. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually increases from top to bottom.
  • the first transition surface 4-1 of the lateral transition surface 4 of type (d) shown in the figure is a twisted surface, and the lateral projection of its front edge 4-1-1 remains vertical, and the rear edge 4-1-1 The lateral projection of 2 is inclined from top to bottom to back. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually increases from top to bottom.
  • the first transition surface 4-1 of the lateral transition surface 4 of type (e) shown in the figure is a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined from top to bottom to the back, and the rear edge
  • the lateral projection of 4-1-2 is inclined from top to bottom.
  • the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually decreases from top to bottom.
  • the first transition surface 4-1 in the lateral transition surface 4 of type (f) shown in the figure is a twisted surface, and the lateral projection of its front edge 4-1-1 remains vertical, and the rear edge 4-1-1
  • the side projection of 2 is inclined from top to bottom. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually decreases from top to bottom.
  • the first transition surface 4-1 of the lateral transition surface 4 of type (g) shown in the figure is a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined from top to bottom to the rear, and the rear edge The lateral projection of 4-1-2 remains vertical. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually decreases from top to bottom.
  • intersection line of the first transition surface 4-1 of the above-mentioned types (a) to (g) and the horizontal plane is a straight line.
  • FIG. 32 is a schematic diagram of a concentrated display of the lateral transition surfaces of types (h) to (n) formed on the pile body.
  • the lateral transition surface 4 of the small section 2 can also have various forms.
  • the first transition surface 4-1 in the lateral transition surface 4 of type (h) shown in the figure is an inner concave surface, which can be specifically a cylindrical surface or an elliptical cylindrical surface, with the front edge 4-1-1 and the rear edge 4 -1-2 are parallel, when viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 remains constant from top to bottom.
  • the first transition surface 4-1 in the lateral transition surface 4 of type (i) shown in the figure is a tapered surface or a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined forward from top to bottom , The lateral projection of the rear edge 4-1-2 is inclined from top to bottom to the back. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually changes from top to bottom Big.
  • the first transition surface 4-1 in the lateral transition surface 4 of type (j) shown in the figure is a conical surface or a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined forward from top to bottom , The lateral projection of the rear edge 4-1-2 remains vertical. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually increases from top to bottom.
  • the first transition surface 4-1 in the lateral transition surface 4 of type (k) shown in the figure is a conical surface or a twisted surface, and the lateral projection of the front edge 4-1-1 remains vertical, and the rear edge 4
  • the lateral projection of -1-2 is inclined from top to bottom to back. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually increases from top to bottom.
  • the first transition surface 4-1 in the lateral transition surface 4 of type (1) shown in the figure is a conical surface or a twisted surface, and the lateral projection of the front edge 4-1-1 remains vertical, and the rear edge 4
  • the lateral projection of -1-2 slopes from top to bottom, and when viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually decreases from top to bottom.
  • the first transition surface 4-1 of the (m) type lateral transition surface 4 shown in the figure is a tapered surface or a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined from top to bottom to back , The lateral projection of the rear edge 4-1-2 is inclined from top to bottom forward. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually changes from top to bottom small.
  • the first transition surface 4-1 of the (n) type lateral transition surface 4 shown in the figure is a conical surface or a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined from top to bottom to back , The lateral projection of the rear edge 4-1-2 remains vertical, when viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually decreases from top to bottom.
  • intersection line of the first transition surface 4-1 of the above-mentioned types (h) to (n) and the horizontal plane is an inwardly concave arc.
  • FIG. 33 is a schematic diagram of a concentrated display of (o) to (u) types of lateral transition surfaces formed on the pile body.
  • the lateral transition surface 4 of the small section 2 can also have various forms.
  • the first transition surface 4-1 in the lateral transition surface 4 of type (o) shown in the figure is an outward convex surface, which can be a cylindrical surface or an elliptical cylindrical surface, with a front edge 4-1-1 and a rear edge 4 -1-2 are parallel, when viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 remains constant from top to bottom.
  • the first transition surface 4-1 of the (p) type lateral transition surface 4 shown in the figure is a tapered surface or a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined from top to bottom to back , The lateral projection of the rear edge 4-1-2 is inclined from top to bottom forward. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually changes from top to bottom small.
  • the first transition surface 4-1 of the lateral transition surface 4 of type (q) shown in the figure is a conical surface or a twisted surface, and the lateral projection of the front edge 4-1-1 remains vertical, and the rear edge 4
  • the lateral projection of -1-2 slopes from top to bottom, and when viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually decreases from top to bottom.
  • the first transition surface 4-1 of the (r) type lateral transition surface 4 shown in the figure is a tapered surface or a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined from top to bottom to back , The lateral projection of the rear edge 4-1-2 remains vertical, when viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually decreases from top to bottom.
  • the first transition surface 4-1 of the side transition surface 4 of type (s) shown in the figure is a conical surface or a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined forward from top to bottom , The lateral projection of the rear edge 4-1-2 is inclined from top to bottom to the back. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually changes from top to bottom Big.
  • the first transition surface 4-1 in the lateral transition surface 4 of type (t) shown in the figure is a conical surface or a twisted surface, and the lateral projection of the front edge 4-1-1 remains vertical, and the rear edge 4
  • the lateral projection of -1-2 is inclined from top to bottom to back. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually increases from top to bottom.
  • the first transition surface 4-1 of the (u) type lateral transition surface 4 shown in the figure is a conical surface or a twisted surface, and the lateral projection of its front edge 4-1-1 is inclined forward from top to bottom , The lateral projection of the rear edge 4-1-2 remains vertical. When viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 gradually increases from top to bottom.
  • intersection line of the first transition surface 4-1 of type (o) to (u) above and the horizontal plane is an arc that protrudes outward.
  • FIG. 34 is a schematic diagram of a concentrated display of the lateral transition surfaces of types (v) to (w) formed on the pile body.
  • the lateral transition surface 4 of the small section 2 can also have various forms.
  • the first transition surface 4-1 of the lateral transition surface 4 of type (v) shown in the figure is an outward convex surface, and its front edge 4-1-1 and rear edge 4-1-2 are parallel arcs. , Bend forward from top to bottom, when viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 remains constant.
  • the first transition surface 4-1 of the lateral transition surface 4 of the type (w) shown in the figure is an inner concave surface, and the front edge 4-1-1 and the rear edge 4-1-2 are parallel arcs. , Bend forward from top to bottom, when viewed from the side, the width between the front edge 4-1-1 and the rear edge 4-1-2 remains constant.
  • the large cross-section section 3 in the middle shown in FIGS. 31 to 34 has only one side formed with the improved first transition surface 4-1, it can be understood that for each large cross-section section 3 in the middle,
  • the lateral transition surfaces 4 on both sides can adopt a symmetrical structure as shown in FIG. 35.
  • the lateral transition surfaces 4 on both sides of the large cross-section section 3 in the middle can also be any of the above two different types of lateral transition surfaces.
  • the prefabricated variable cross-section square piles are prefabricated by reinforced concrete in the factory building. After the prefabricated piles are connected, gaps are easily generated at the piles. Therefore, underground acid and alkali corrosive substances can easily enter the piles from the gaps to corrode the metal connectors. In order to solve this problem, the solution in the following embodiment can be adopted.
  • variable cross-section prefabricated square pile Since in these embodiments, we will mainly introduce the end structure of the variable cross-section prefabricated square pile and the internal steel bar structure, for the sake of simplicity, the variable cross-section prefabricated square pile shown in the figure adopts a simple drawing method, and the large section is not shown. Such omission of sections, small cross-section sections and lateral transition surfaces will not affect the understanding and reproduction of the technical solutions of the present invention by those skilled in the art.
  • FIG. 36 is a schematic diagram of the installation structure of the variable cross-section prefabricated square pile disclosed in the twelfth embodiment of the present invention.
  • variable cross-section prefabricated square pile is a concrete member prefabricated in a factory.
  • the external object is a concrete member, such as a platform, a foundation, etc.; wherein the mechanical connector 14 is a commonly used mechanical connector in the field (such as the connectors disclosed in patent documents CN201510649253.6, CN201510314380.0, etc.).
  • At least one pile end surface 19 of the prefabricated pile has a groove 11 for at least partially accommodating the storage block 10 storing the viscous substance 12.
  • the storage block 10 is pressed to release the viscous substance 12 ,
  • the viscous substance 12 overflows the groove 11 to separate the connecting hole 9 and the edge of the pile end surface 19 closest to the connecting hole, thereby protecting the mechanical connector 14 and preventing dust, sand, water, etc. from entering through the gap between the pile end surface 19 and external objects
  • the mechanical connection 14 further corrodes the mechanical connection 14.
  • the upper end surface and the lower end surface of the precast pile are respectively provided with grooves 11, as shown in FIG. 36; in order to make the viscous substance 12 uniformly protect the mechanical connectors 14 in all the connecting holes 9, the concave
  • the groove 11 is placed at the center of the pile end surface 19 of the precast pile, and the shape of the groove 11 can be set according to the shape of the pile end surface 19 of the precast pile, and it can be circular, ring, rectangular or regular polygon, etc.; groove 11 It can also be ring-shaped, with a groove 11 surrounding all the connecting holes 9 or each connecting hole 9 to separate the connecting hole 9 from the edge of the pile end surface 19, as shown in Figures 37-38; because the viscous substance 12 has Fluidity, it can flow along the pile end surface 19 after being squeezed out of the groove 11.
  • the annular groove 11 can also only surround part of the connecting hole 9, or only part of the connecting hole 9 is respectively surrounded by an annular groove 11;
  • the pile end surface 19 has a plurality of grooves 11, they can be combined and set according to the shape and position of the above grooves 11, as shown in Figures 39-40.
  • the grooves 11 can also have other shapes and other positions and The combination method is not limited to the case shown in this embodiment.
  • the groove 11 in order to ensure that the storage block 10 can be stably placed in the groove 11, and the storage block 10 can be compressed and after the viscous substance 12 overflows the groove 11, a sufficient amount of viscous substance 12 can be stored in the groove 11 ,
  • the depth of the groove 11 is set to be greater than 0.5% of the diameter of the prefabricated pile and less than the height of the storage block 10.
  • FIG. 41 is a schematic diagram of the pile connection process of the variable cross-section prefabricated square pile disclosed in the thirteenth embodiment of the present invention
  • FIG. 42 is a schematic diagram of the completed state of the variable cross section prefabricated square pile in FIG. 41.
  • This embodiment provides a pile connecting structure, which includes a viscous substance 12, at least two prefabricated piles that are vertically butted in sequence, and at least one storage block 10 between two adjacent prefabricated piles and storing the viscous substance; and At least one of the two prefabricated piles is the prefabricated pile provided in the first embodiment, and the two adjacent prefabricated piles that are vertically butted in turn are the upper section prefabricated pile and the lower section prefabricated pile.
  • the compressed storage block 10 can release the viscous substance 12 to eliminate And/or fill the gap between the end faces of two adjacent precast piles.
  • the lower end face of the upper section precast pile and the upper end face of the lower section precast pile are respectively provided with grooves 11, and the positions of the grooves 11 on the two precast piles correspond to each other and the shapes are matched.
  • the shapes of the grooves 11 on the two precast piles are also The space in which the grooves 11 on the two prefabricated piles may not be adapted and overlapped axially can accommodate the storage block 10.
  • the storage block 10 can be compressed to the smallest
  • the thickness is less than or equal to the sum of the depths of the two corresponding grooves 11; of course, the shape of the corresponding groove 11 may not match or correspond to each other.
  • the minimum thickness that the storage block 10 can reach after being compressed is less than or equal to the depth of the groove 11 where it is located; as another preferred solution, only the lower end face of the upper section precast pile and the upper end face of the lower section precast pile A groove 11 is provided on the end face 19 of the pile.
  • the minimum thickness that the storage block 10 can reach after being compressed is less than or equal to the depth of the groove 11;
  • the actual situation is to set whether there are grooves 11 on the end faces of the two prefabricated piles and the positions of the grooves 11, which can be other positions and combinations, and are not limited to the situation shown in this embodiment;
  • the storage block 10 is made of elastic water-absorbing material , Such as sponge, etc., has good elasticity and water absorption, can absorb and store a large amount of viscous substance 12, the viscous substance 12 is generally epoxy resin or modified epoxy resin and other materials that can flow and have curability.
  • the viscous substance 12 is squeezed out of the storage block 10 and overflows the groove 11 and then covers the end face 19 of the pile to isolate the end face 19 of the pile to prevent it from contacting the outside air, water or sand, etc., to seal and anticorrosive the end face of the prefabricated pile Protection;
  • the storage block 10 can also be a capsule made of flexible material, filled with a certain amount of viscous substance 12, when the pile end surface 19 is squeezed, the storage block 10 ruptures, the viscous substance 12 from the cracked gap Or the storage block 10 has small holes. When pressed, the small holes are enlarged and the viscous substance 12 is squeezed out of the small holes.
  • the viscous substance 12 in the storage block 10 flows in through the end face 19 of the pile and fills the mechanical connector 14, which is convenient and quick, and improves the work efficiency; at the same time, since the volume of the storage block 10 is a fixed value, that is, its internal The stored viscous substance 12 is also a fixed value, which realizes the quantitative use of the viscous substance 12, prevents the waste of the viscous substance 12 caused by improper operation, and saves costs; the precast pile in the upper section is pressed down, and the viscous substance 12 in the storage block 10 is squeezed Flows out and flows along the end face 19 of the pile; continue to press down until the end face of the pile is attached, and the storage block 10 is completely compressed in the groove 11, as shown in Figure 42, at this time, the pile connection is completed; due to the elasticity of the storage block 10 After being compressed, it
  • Figure 43 is a schematic diagram of the connecting structure of the variable cross-section prefabricated square pile disclosed in the fourteenth embodiment of the present invention
  • Figure 44 is a schematic diagram of the completed state of the variable cross-section prefabricated square pile connecting pile in Figure 43
  • Figure 45 is an enlarged view of the structure at D in Figure 43.
  • the pile connecting structure of this embodiment also includes a corrosion-resistant sealing ring 15 which is sleeved at the junction of two adjacent vertically butted precast piles; the sealing ring is installed before the piles are connected. 15 is set on the pile body close to the end face 19 of the pile, and then the two precast piles are connected. After the pile connection is completed, the sealing ring 15 is dragged to move it to the place where the end faces of the two precast piles fit and wrap it; The sealing ring 15 has certain elasticity. After the sheathing is completed, the sealing ring 15 is pressed against the prefabricated pile to seal the joint of the pile end surface 19 to prevent the viscous substance 12 from flowing out without solidification and reduce the loss of the viscous substance 12.
  • the diameter of the pile end of the precast pile is smaller than the diameter of the pile body
  • the thickness of the sealing ring 15 is less than or equal to 1/2 of the difference between the diameter of the pile body and the pile end diameter
  • the width of the sealing ring 15 is less than or equal to 2 times the length of the pile end
  • Figure 46 is a schematic structural diagram of the rigid frame of the variable cross-section precast square pile disclosed in the fifteenth embodiment of the present invention
  • Figure 47 is the end of the rigid frame shown in Figure 46 View
  • Figure 55 is a schematic view of the structure of the auxiliary stirrup
  • Figure 56 is a schematic view of the structure of the rigid mesh cover
  • the rigid frame for the pile of the variable cross-section prefabricated square pile in this embodiment includes: a rigid frame for the precast pile with a plurality of main reinforcements 21 arranged at intervals and surrounded by a reserved cavity, and a tightening and fixing station
  • the skeleton stirrup 22 of the main reinforcement skeleton is covered with a rigid mesh cover 26 and/or rigid mesh 23 to strengthen the structural strength of the prefabricated pile at the end of the main reinforcement skeleton.
  • the end of the main reinforcement skeleton is fastened and fixed by the auxiliary stirrup 24, and the auxiliary
  • the spacing of the stirrups 24 is less than or equal to the spacing of the frame stirrups.
  • the rigid mesh cover 26 is added at the end of the main reinforcement frame, and at the same time, the auxiliary stirrup 24 is wound around the end of the main reinforcement frame to tighten the rigid mesh cover 26 and the main reinforcement 21, which can prevent pumping during the production of precast concrete piles.
  • the concrete impacts and explodes the main reinforcement 21 at the end of the main reinforcement skeleton to protect the end structure of the main reinforcement skeleton. It can also prevent the main reinforcement 21 from being impacted and exploded during pile driving and strengthen the end structure strength of the concrete precast pile. If the distance between the auxiliary stirrup and the main reinforcement 21 is large, the main reinforcement skeleton cannot be prevented from exploding. Therefore, the auxiliary stirrup 24 needs to be close to the main reinforcement 21.
  • the rigid frame for the precast pile is a steel cage
  • the frame stirrups and auxiliary stirrups are spiral stirrups
  • the rigid mesh cover 26 is a steel mesh cover.
  • the auxiliary stirrup 24 and the rigid mesh cover 26 are connected and fixed, and the auxiliary stirrup 24 is located outside the rigid mesh cover 26.
  • the main reinforcement frame can withstand greater hammering force and prevent the auxiliary stirrup 24 from loosening.
  • the rigid net cover 26 includes a number of ring ribs 26-1 arranged at intervals along the length of the main rib frame and a number of axial ribs 26-2 connecting and fixing the ring ribs 26-1.
  • the direction rib 26-2 is parallel to the main rib 21.
  • the axial ribs 26-2 are fixedly connected along the inner circumferential direction of the ring ribs 26-1, which can ensure that the rigid mesh cover 26 receives uniform force.
  • a rigid net cover 26 is sleeved at the end of the main reinforcement frame, which can hoop the end of the main reinforcement frame together with the auxiliary stirrup 24, so that the main reinforcement 21 of the main reinforcement frame is more difficult to explode.
  • the rigid mesh cover 26 may be a steel mesh cover.
  • the rigid mesh 23 is arranged at the end of the main rib skeleton and arranged at intervals along the length direction of the reserved cavity. It can strengthen the structural strength and anti-hammering ability of the end of the concrete precast pile, and prevent the end of the concrete precast pile from being exploded when the pile is sinking.
  • the rigid mesh 23 can be provided separately, or the rigid mesh cover 26 can also be provided separately, or the rigid mesh 23 and the rigid mesh cover 26 can be provided together.
  • the rigid mesh 23 includes a plurality of cross-connected and fixed reinforcing ribs 23-1, and the end of the rigid mesh 23 is fixedly connected with the auxiliary stirrup 24 and/or the main rib framework.
  • the rigid mesh 23 is in the shape of a grid, which can not only strengthen the strength of the end of the concrete precast pile, but also ensure that the concrete can fully wrap the ribs 23-1 when the concrete precast pile is made, so as to ensure that the force is uniform and the rigid mesh
  • the end of 23 can be connected with the auxiliary stirrup 24, or with the main reinforcement 21, or connected with the auxiliary stirrup 24 and the main reinforcement 21, so as to ensure the stable connection of the rigid mesh 23.
  • the plane where the rigid mesh 23 is located is perpendicular to the central axis of the axial rib 26-2.
  • the rigid mesh 23 is arranged on the rigid mesh cover 26 perpendicularly to the axial ribs 26-2 in sequence, and the reserved cavity is divided into several small spaces in the length direction, which can make the concrete at the end of the concrete precast pile more compact.
  • the rigid mesh 23 is connected to the rigid mesh cover 26, and then sleeved into the end of the main rib skeleton, the rigid mesh 23 can be pre-connected to the rigid mesh cover 26 to form an integrated structure, so that the rigid mesh 23 It is easier to place. At least one rigid mesh 23 is connected to the end of the rigid mesh cover 26, so that the rigid mesh cover 26 has a blocking surface, and strengthens the structural strength of the end of the rigid mesh cover 26.
  • connection form of the rigid mesh 23 on the rigid mesh cover 26 It can be that the rigid mesh 23 is connected to the ring rib 26-1, or the rigid mesh 23 is connected to the axial rib 26-2, or part of the rigid mesh 23 is connected to the ring rib 26-1, and part of the rigid mesh is connected to the ring rib 26-1. 23 is connected to the axial rib 26-2.
  • the skeleton stirrup 22 is used to tighten the main reinforcement 21 to form the main reinforcement skeleton, and at the same time, the rigid mesh 23 is connected to the rigid mesh cover 26, and then the rigid mesh cover 26 is sleeved to the end of the main reinforcement skeleton. Finally, the auxiliary stirrups 24 are used to tighten the rigid mesh cover 26 and the main reinforcement 21. It can prevent the main reinforcement 21 at the end of the main reinforcement skeleton from being impacted and exploded by pumping concrete during the production of precast concrete piles, protecting the end structure of the main reinforcement skeleton, and at the same time strengthening the end structure strength and hammer resistance of the precast concrete piles, which can prevent sinking. When the pile is piled, the end of the concrete precast pile burst open.
  • FIG. 48 is a schematic structural diagram of a rigid skeleton of a variable cross-section prefabricated square pile disclosed in the sixteenth embodiment of the present invention
  • FIG. 49 is an end view of the rigid skeleton shown in FIG. 48.
  • a connecting nut 25 is provided at the end of the main rib 21, and the auxiliary stirrup 24 is connected and fixed to at least one of the connecting nuts 25.
  • the precast piles are connected by connecting nuts 25 and inserting rods, so connecting nuts 25 are arranged at the top of the main reinforcement 21. If the auxiliary stirrups 24 are separated from the connecting nuts 25 by a large distance, it will not prevent the main reinforcement skeleton from exploding, so the auxiliary stirrups 24.
  • At least one connecting nut 25 needs to be connected and fixed, so as to prevent the connecting nut 25 from being struck by a hammer and falling apart, resulting in displacement of the connection between the prefabricated piles.
  • FIG. 50 is a schematic diagram of the structure of the rigid skeleton of the variable cross-section prefabricated square pile disclosed in the seventeenth embodiment of the present invention
  • FIG. 51 is an end view of the rigid skeleton shown in FIG. 50.
  • the difference of this embodiment is that the plane where the rigid mesh 23 is located is parallel to the central axis of the axial rib 26-2.
  • the rigid mesh 23 is arranged on the rigid mesh cover 26 in turn parallel to the axial ribs 26-2, and the reserved cavity is divided into several small spaces in the width direction or the height direction, so that the concrete at the end of the concrete precast pile Closer.
  • connection form of the rigid mesh 23 on the rigid mesh cover 26 may be that two opposite ends of the rigid mesh 23 are connected to the rigid mesh cover 26.
  • Figure 52 is a schematic structural diagram of the rigid skeleton of the variable cross-section prefabricated square pile disclosed in the eighteenth embodiment of the present invention
  • Figure 53 is an end view of the rigid skeleton shown in Figure 52
  • 57 is a schematic diagram of the structure of the C-type hoop.
  • the difference of this embodiment is that a number of C-shaped hoops 27 are further provided on the end surface of the main rib skeleton, and the opening of the C-shaped hoops 27 faces the middle section of the reserved cavity.
  • the C-shaped hoop 27 can make the end of the main reinforcement skeleton form a blocking surface, make the end structure of the main reinforcement skeleton more stable, and strengthen the structural strength of the end surface of the concrete precast pile.
  • the C-shaped hoop 7 is arranged in the reserved cavity of the main reinforcement skeleton in a horizontal or longitudinal order evenly; or, the C-shaped hoop 7 is arranged crosswise in the reserved cavity of the main reinforcement skeleton; the C-shaped casing
  • the hoop 7 is fixedly connected to the auxiliary stirrup 24 or/and the rigid net cover 26.
  • the C-shaped hoop 27 adopts the above arrangement to form a retaining surface, which can strengthen the structural strength of the end face of the concrete precast pile, and at the same time can tighten the rigid mesh cover 26 together with the auxiliary stirrup 24.
  • the C-shaped hoop 27 is arranged crosswise on the end face of the main reinforcement frame.
  • the end of the rigid mesh 23 in the fifteenth embodiment can also be connected with the C-shaped hoop 27.
  • the end of the rigid mesh 23 is connected and fixed with the rigid mesh cover 26, the C-shaped hoop 7 is connected and fixed with the end of the rigid mesh cover 26, and the C-shaped hoop 27 is located inside the rigid mesh cover 26.
  • the rigid mesh 23 can be connected to the C-shaped hoop 27, and then connected to the rigid mesh cover 26 to form an integrated structure, and then sleeved into the end of the main rib skeleton, making the placement of the rigid mesh 23 easier.
  • the main rib 21 is hooped with the skeleton stirrup 22 to form the main rib skeleton.
  • the C-shaped hoop 7 is first connected to the end of the rigid mesh cover 26 to form a blocking surface, and then the rigid The mesh 23 is connected to the rigid mesh cover 26, and then the rigid mesh cover 26 is sleeved to the end of the main rib skeleton, and finally the rigid mesh cover 26 and the main rib 21 are tightened with the auxiliary stirrup 24.
  • the structure also makes the skeleton structure of the main reinforcement more stable, and can make the concrete at the end of the concrete precast pile more compact, thereby strengthening the end structure strength and the hammer resistance ability of the concrete precast pile.
  • the cross section area of the small section section 2 is S1
  • the total cross section area of the steel rod is S2
  • the ratio of S2 to S1 is at least 0.5% to 0.15%
  • the proportion of the stressed tendons is high, which improves the structural strength and pull-out strength of the pile body.
  • the length of the dense area of spiral stirrups at both ends of the pile is greater than the length of the large section 3 at the end, and the density of the dense area of spiral stirrups at both ends of the pile is 1.5-3 times that of the ordinary area to improve the structural strength of the pile end and the impact resistance.
  • the spacing between steel rods is greater than or equal to 50mm to facilitate pouring or pumping of concrete, coarse aggregates (ie stones) can be evenly distributed; the pile end is increased with steel mesh cover 26 and steel mesh 23, which can improve the resistance of the pile end.
  • the lateral transition surface 4 is an inner concave surface or an outer convex surface, the traces on the front edge or the back edge will not be very obvious due to the smooth transition, which may be difficult to distinguish by human eyes. At this time, you can follow the boundary of the lateral transition surface 4 Make auxiliary lines to define the position of its front or back edge.
  • variable cross-section prefabricated square piles claimed by the present invention include variable cross-section solid square piles and variable cross-section hollow square piles.
  • U-shaped molds can be used for production, or they can be opened diagonally. Closed molds for production.
  • the present invention is very advantageous for demoulding, and can avoid cracking or falling off of the concrete protective layer caused by violent demoulding.

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Abstract

一种混凝土变截面预制桩，包括沿纵向交替排列有大截面段和小截面段的桩体；所述大截面段与相邻的所述小截面段的侧表面之间形成有侧向过渡面；至少部分数量的所述侧向过渡面具有在侧向投影上偏离竖直方向的前边沿和/或后边沿，且该侧向过渡面与第一水平面的相交线的垂向投影位于该侧向过渡面与第二水平面的相交线的垂向投影的外侧；所述第一水平面为任意两个水平面中位于上方的水平面，所述第二水平面为任意两个水平面中位于下方的水平面，所述小截面段的一个或两个侧表面垂直于所述小截面段的底面或者侧倾斜设定角度。该预制桩可以减少中间段容易损坏的现象，降低变截面预制方桩的破损率，使变截面预制方桩的产品质量更加稳定可靠。

Description

混凝土变截面预制方桩
本申请要求下述专利申请的优先权，其全部内容通过引用结合在本申请中：
1)2019年09月04日提交中国专利局、申请号为201921464635.1、发明名称为“一种预制变截面四面桩”的实用新型专利申请。
2)2020年05月06日提交中国专利局、申请号为202010371564.1、发明名称为“混凝土变截面预制方桩”的发明专利申请。
技术领域
本发明涉及混凝土预制桩技术领域，特别是混凝土变截面预制方桩。
背景技术
混凝土预制桩是在工厂预制的内部具有钢筋笼的混凝土预制构件。
预制桩包括直桩与变截面桩，顾名思义，直桩的桩身在长度方向上各横截面形状和尺寸均相同，而变截面桩的桩身横截面尺寸及形状沿桩长度会发生变化，与直桩相比，变截面桩具有更好的抗拔和承载性能，越来越受到建筑行业的青睐。
如CN 204738291 U公开的一种预制混凝土竹节实心方桩，其包括桩身截面为方形的桩身，且包括两个分别位于桩身上端和桩身下端的大截面节段、以及位于两个所述大截面节段之间的中间段；所述中间段两端设有小截面节段，所述大截面节段的截面积大于小截面节段的截面积；所述大截面节段和小截面节段之间通过斜面过渡。这种方桩具备高竖向承载力高、强水平抗剪力、良好抗腐蚀性能、较强抗拔性能的多种综合性能。
实际工程应用时，在沉桩前对方桩进行检查的过程中，有一定的概率会发现变截面桩的中间段存在不同程度的损坏，例如表面裂纹、材料破损或脱落等，一旦发现此类现象，便需要评估发生损坏的方桩是否能够继续正常使用，通常情况下，为了保证工程质量和施工进度，存在严重缺陷的方桩将不再继续使用，只能作为建筑废料进行处理。
对于这种情况，长期以来，业内人士都通常都将其归咎于混凝土配方 或制作工艺的问题，也有观点认为是转运过程中的粗暴操作造成的，并分别朝着这些方向进行了探索和改进。
但是，在经过了相当长的一段时间之后，这一问题依然未能得到有效的解决。
发明内容
本发明的目的在于提供一种混凝土变截面预制方桩，以减少中间段容易损坏的现象，降低变截面预制方桩的破损率，使变截面预制方桩的产品质量更加稳定可靠，从而更好的满足实际使用要求。
为实现上述目的，本发明提供一种混凝土变截面预制桩，包括沿纵向交替排列有大截面段和小截面段的桩体，所述大截面段和小截面段的横截面大体呈矩形；所述大截面段与相邻的所述小截面段的侧表面之间形成有侧向过渡面；至少部分数量的所述侧向过渡面具有在侧向投影上偏离竖直方向的前边沿和/或后边沿，且该侧向过渡面与第一水平面的相交线的垂向投影位于该侧向过渡面与第二水平面的相交线的垂向投影的外侧；所述第一水平面为任意两个水平面中位于上方的水平面，所述第二水平面为任意两个水平面中位于下方的水平面，所述小截面段的一个或两个侧表面垂直于所述小截面段的底面或者自上而下向桩体内侧倾斜设定角度。
优选地，所述侧向过渡面在侧向投影上偏离竖直方向的前边沿和/或后边沿为倾斜的边沿或弯曲的边沿。
优选地，位于两端之间的所述大截面段的侧表面的前边沿和后边沿为竖直边沿，其面宽自上而下保持恒定；或者，位于两端之间的所述大截面段的侧表面的前边沿和/或后边沿在侧向投影上偏离竖直方向，其面宽自上而下变大或变小。
优选地，所述侧向过渡面包括位于小截面段前部的第一过渡面和位于小截面段后部的第二过渡面，所述第一过渡面的后边沿自上而下向前倾斜或弯曲；和/或，所述第二过渡面的前边沿自上而下向后倾斜或弯曲。
优选地，所述侧向过渡面包括位于小截面段前部的第一过渡面和位于小截面段后部的第二过渡面，所述第一过渡面的前边沿自上而下向前倾斜 或弯曲；和/或，所述第二过渡面的后边沿自上而下向后倾斜或弯曲。
优选地，所述侧向过渡面为平面，其前边沿平行于后边沿，面宽自上而下保持恒定，或者，所述侧向过渡面为平面，其前边沿与后边沿不平行，面宽自上而下变大或变小；或者，
所述侧向过渡面为曲面，其前边沿平行于后边沿，面宽自上而下保持恒定，或者，所述侧向过渡面为曲面，其前边沿与后边沿不平行，面宽自上而下变大或变小。
优选地，所述侧向过渡面为内凹的曲面、外凸的曲面或扭曲面。
优选地，所述内凹的曲面包括内凹的弧面或内凹的锥面，所述外凸的曲面包括外凸的弧面或外凸的锥面。
优选地，所述侧向过渡面与第一水平面的相交线的垂向投影的延长线与该侧向过渡面与第二水平面的相交线的垂向投影的延长线相交。
优选地，所述桩体具有桩端面，至少一桩端面具有凹槽和多个间隔布置的连接孔，所述凹槽用于至少部分容纳存储有粘性物质的存储块，所述凹槽深度小于存储块的初始高度，在预制方桩对接时，压缩所述存储块可释放粘性物质以消除和/或填充相对接预制方桩的接桩端面间隙。
优选地，所述容纳槽的槽深大于等于1mm、槽宽大于等于1mm，且所述容纳槽距所述连接孔0.5cm以上。
优选地，所述容纳槽的槽深为2mm-20mm。
优选地，至少一个所述凹槽呈圆形或环形或矩形或正多边形且位于桩端面的中心处；
和/或，至少一个所述凹槽为环状且环绕所有连接孔；
和/或，至少一个所述凹槽为环状且环绕部分连接孔；
和/或，至少一个所述凹槽为环状且环绕单个连接孔。
优选地，其刚性骨架包括：由多根主筋间隔排列且环绕形成有预留空腔的主筋骨架，以及箍紧所述主筋骨架的骨架箍筋；
其中，所述主筋骨架的端部套有加强预制桩结构强度的刚性网罩和/或刚性网片，主筋骨架的端部由辅助箍筋箍紧固定，且辅助箍筋的缠绕间距小于或等于骨架箍筋的缠绕间距。
优选地，所述辅助箍筋形成箍筋加密区，所述箍筋加密区的长度大于 端部大截面段的长度；所述箍筋加密区的缠绕密度为非加密区的1.5-3倍。
优选地，主筋骨架端面还设有若干开口朝向预留空腔的中部的C型套箍。
优选地，所述主筋端部连接有连接螺母，所述辅助箍筋至少连接固定其中一个连接螺母。
优选地，所述C型套箍横向或纵向依次间隔排列设置在主筋骨架的预留空腔内；和/或，C型套箍交叉设置在主筋骨架的预留空腔内；所述C型套箍与辅助箍筋或/和刚性网罩固定连接。
优选地，辅助箍筋和刚性网罩连接固定，且刚性网罩位于辅助箍筋的内部；
或者，所述刚性网罩包括若干沿主筋骨架长度方向依次间隔排列的环筋以及若干连接固定各环筋的轴向筋，其中，轴向筋平行于主筋；
或者，所述刚性网片设置于主筋骨架的端部且沿所述预留空腔的长度方向间隔配置。
优选地，所述桩体两端的大截面段长度大于中间部分的大截面段长度，所述桩体两端的大截面段长度大约为中间部分的大截面段长度的2倍～6倍；
和/或，在所述小截面段的横截面上，所述小截面段的横截面面积为S1，钢棒横截面面积总和为S2，S2占S1的比值至少为0.5％～0.15％。
本发明采用以上结构设计，与现有技术相比，增强了变截面预制方桩顶面以及侧向过渡面的强度，使得变截面预制方桩在起吊时顶面的抗压强度增强，而底面受到的拉力减小，实现了提高变截面预制方桩抗弯性能的效果，减小了变截面预制方桩在起吊时裂纹的产生，提高了桩身质量，减小了废桩退桩率。
而且，由于侧向过渡面的前边沿和/或后边沿在侧向投影上偏离竖直方向，增大了侧向过渡面的面积，改变了侧摩擦阻力系数，从而提高了变截面预制方桩桩身的侧摩擦阻力和抗压抗拔性能，在同样的工况下，可以减小预制桩规格，提高性价比，顺应国家节能减排的政策。
此外，还可以提高变截面预制方桩制作时的脱模效率，提升桩身质量。比如在脱模过程中，可以释放预应力张拉力，可以有效防止变截面处将模 具凸出部抱死的情况，可以减少变截面预制方桩竹节的破损，减少人工修补破损的人工消耗，桩身的整体性好，桩身强度高。
附图说明
图1为本发明第一实施例公开的变截面预制方桩的结构示意图；
图2为图1所示变截面预制方桩在另一视角下的结构示意图；
图3为图1所示变截面预制方桩的俯视图；
图4为图3中A部位的局部放大图；
图5为本发明第二实施例公开的变截面预制方桩的俯视图；
图6为图5中B部位的局部放大图；
图7为本发明第三实施例公开的变截面预制方桩的局部放大图；
图8为本发明第四实施例公开的变截面预制方桩的局部放大图；
图9为本发明第五实施例公开的变截面预制方桩的结构示意图；
图10为图9所示变截面预制方桩的俯视图；
图11为本发明第六实施例公开的变截面预制方桩的结构示意图；
图12为本发明第七实施例公开的变截面预制方桩的结构示意图；
图13为本发明第八实施例公开的变截面预制方桩的结构示意图；
图14为图13的局部放大图；
图15为图14的仰视图；
图16为图13所示变截面预制方桩的侧视图；
图17为图13所示变截面预制方桩的底部边沿具有倒角的端部示意图；
图18为图13所示变截面预制方桩的底部边沿具有倒角的局部结构示意图；
图19为图13所示变截面预制方桩的顶部边沿圆滑过渡的端部示意图；
图20为图13所示变截面预制方桩的底面边沿圆滑过渡的局部结构示意图；
图21为图13所示变截面预制方桩的顶部和底部边沿具有倒角的端部示意图；
图22为图13所示变截面预制方桩的顶部和底部边沿具有倒角的局部 结构示意图；
图23为图13所示变截面预制方桩的顶部边沿具有倒角、底部边沿圆滑过渡的端部示意图；
图24为图13所示变截面预制方桩的顶部边沿具有倒角、底部边沿圆滑过渡的局部结构示意图；
图25为本发明第九实施例公开的变截面预制方桩的结构示意图；
图26为本发明第十实施例公开的变截面预制方桩的结构示意图；
图27为本发明第十一实施例公开的变截面预制方桩的结构示意图；
图28为图27所示变截面预制方桩的侧视图；
图29为图27所示变截面预制方桩的仰视图；
图30为图29中C部位的局部放大图；
图31为桩体上所形成的(a)～(g)类型的侧向过渡面的集中展示示意图；
图32为桩体上所形成的(h)～(n)类型的侧向过渡面的集中展示示意图；
图33为桩体上所形成的(o)～(u)类型的侧向过渡面的集中展示示意图；
图34为桩体上所形成的(v)～(w)类型的侧向过渡面的集中展示示意图；
图35为同一大截面段的前部侧向过渡面和后部侧向过渡面相对称的局部结构示意图；
图36为本发明第十二实施例公开的变截面预制方桩的安装结构示意图；
图37为图36中预制桩端面凹槽位置及形状的一种示意图；
图38为图36中预制桩端面凹槽位置及形状的另一种示意图；
图39为图36中预制桩端面凹槽位置及形状的另一种示意图；
图40为图36中预制桩端面凹槽位置及形状的另一种示意图；
图41为本发明第十三实施例公开的变截面预制方桩的接桩过程示意图；
图42为图41中变截面预制方桩接桩完成状态示意图；
图43为本发明第十四实施例公开的变截面预制方桩的接桩结构示意图；
图44为图43中变截面预制方桩接桩完成状态示意图；
图45为图43中D处结构放大图；
图46为本发明第十五实施例公开的变截面预制方桩的刚性骨架的结构示意图；
图47为图46所示刚性骨架的端部视图；
图48为本发明第十六实施例公开的变截面预制方桩的刚性骨架的结构示意图；
图49为图48所示刚性骨架的端部视图；
图50为本发明第十七实施例公开的变截面预制方桩的刚性骨架的结构示意图；
图51为图50所示刚性骨架的端部视图；
图52为本发明第十八实施例公开的变截面预制方桩的刚性骨架的结构示意图；
图53为图52所示刚性骨架的端部视图；
图54为刚性网片的结构示意图；
图55为辅助箍筋的结构示意图；
图56为刚性网罩的结构示意图；
图57为C型套箍的结构示意图。
图中：
1.桩体 2.小截面段 2-1.上边沿 2-2.下边沿 3.大截面段 3-1.上边沿 3-2.下边沿 4.侧向过渡面 4-1.第一过渡面 4-1-1.前边沿 4-1-2.后边沿 4-2.第二过渡面 4-2-1.前边沿 4-2-2.后边沿 4-2-3.上边沿 4-2-4.下边沿 5.左凸起部 6.右凸起部 7.上凸起部 8.下凸起部 9.连接孔 10.存储块 11.凹槽 12.粘性物质 13.钢筋 14.机械连接件 15.密封圈 16.混凝土构件 17.桩端 18.平滑过渡部 19.桩端面 21.主筋 22.骨架箍筋 23.刚性网片 23-1.加强条筋 24.辅助箍筋 25.连接螺母 26.刚性网罩 26-1.环筋 26-2.轴向筋 27.C型套箍
具体实施方式
为了使本技术领域的人员更好地理解本发明方案，下面结合附图和具体实施方式对本发明作进一步的详细说明。
在本文中，“上、下、左、右、前、后”等用语是基于附图所示的位置关系而确立的，根据附图的不同，相应的位置关系也有可能随之发生变化，因此，并不能将其理解为对保护范围的绝对限定；而且，诸如“第一”和“第二”等之类的关系术语仅仅用来将一个与另一个具有相同名称的部件区分开来，而不一定要求或者暗示这些部件之间存在任何这种实际的关系或者顺序。
预制桩的施工程序主要分为预制、运输、堆放、沉桩，在各施工程序中，预制桩难以避免被频繁起吊。
现有的起吊方式是在桩身顶部设置吊钩，利用起吊设备对预制桩进行起吊。根据预制桩的桩身长度和质量，在桩身上设置两个吊钩进行两点起吊的方式应用较多。两点起吊时，由于起吊力和桩身重力的共同作用，在起吊方向上，桩身顶面位于桩身底面上方，桩身顶面受压，桩身底面受拉。
经发明人研究发现，由于混凝土具有抗压强度远大于抗拉强度的性能且桩身重力大，桩身底面和侧向过渡面极易由于受拉强度较大而导致出现裂纹，这是造成桩身损坏的原因之一，而现有的变截面桩虽然在长度方向上，横截面会有所变化，但在高度方向上的各截面保持一致；因此，当变截面桩受拉强度较大时，总是底面先被损坏进而导致整根桩报废。
基于这一研究结论，本发明对变截面预制方桩的结构做了进一步改进，以在一定程度上改善或消除变截面预制方桩存在的上述技术问题。
请参考图1至图4，图1为本发明第一实施例公开的变截面预制方桩的结构示意图；图2为图1所示变截面预制方桩在另一视角下的结构示意图；图3为图1所示变截面预制方桩的俯视图；图4为图3中A部位的局部放大图。
如图所示，在第一实施例中，本发明所提供的混凝土变截面预制桩，其桩体1沿前后方向交替排列有四个小截面段2和三个大截面段3，大截面段3和小截面段2的横截面大体呈矩形，桩体的顶面、右侧面和底面为平面，左侧面为凹凸面，其中每一个大截面段3的左侧相对于小截面段2 向外凸起，每一个小截面段2与左凸起部5之间形成有侧向过渡面4。
以位于中间的一个小截面段2为例，其两侧的表面，也就是图中所示的左侧表面和右侧表面垂直于底面，大截面段3的左侧表面和右侧表面也垂直于底面，小截面段2与前部的大截面段3之间形成的侧向过渡面3为第一过渡面4-1，与后部的大截面段3之间形成的侧向过渡面为第二过渡面4-2。
第一过渡面4-1为倾斜的平面，其前边沿4-1-1和后边沿4-1-2为直线边沿，两者相互平行，且前边沿4-1-1和后边沿4-1-2在侧向投影上均偏离竖直方向，自上而下向前倾斜一定角度。从俯视图上可以看出，如果将任意两个水平面与第一过渡面4-1的相交的线做垂向投影，则第一过渡面4-1与第一水平面的相交线的垂向投影L1位于第一过渡面4-1与第二水平面的相交线的垂向投影L2的外侧，其中，第一水平面4-1为任意两个水平面中位于上方的水平面，第二水平面为任意两个水平面中位于下方的水平面。
第二过渡面4-2为斜向的平面，其前边沿4-2-1和后边沿4-2-2为直线边沿，两者相互平行，且前边沿4-2-1和后边沿4-2-2在侧向投影上保持竖直方向，并没有向前或向后倾斜。
具有该结构的变截面预制方桩可以增强顶面以及侧向过渡面4的强度，使得变截面预制方桩在起吊时顶面的抗压强度增强，而底面受到的拉力减小，实现了提高变截面预制方桩抗弯性能的效果，减小了变截面预制方桩在起吊时裂纹的产生，提高了桩身质量，减小了废桩退桩率。
而且，由于第一过渡面4-1的前边沿4-1-1和后边沿4-1-2在侧向投影上偏离竖直方向，增大了第一过渡面4-1的面积，改变了侧摩擦阻力系数，从而提高了变截面预制方桩桩身的侧摩擦阻力和抗压抗拔性能，在同样的工况下，可以减小预制桩规格，提高性价比，顺应国家节能减排的政策。
此外，还可以提高变截面预制方桩制作时的脱模效率，提升桩身质量。比如在脱模过程中，可以释放预应力张拉力，可以有效防止变截面处将模具凸出部抱死的情况，可以减少变截面预制方桩竹节的破损，减少人工修补破损的人工消耗，桩身的整体性好，桩身强度高。
请参考图5、图6，图5为本发明第二实施例公开的变截面预制方桩的俯视图；图6为图5中B部位的局部放大图。
本实施例中，与第一实施例相同的部分，给予相同的附图标记，并省略相同的文字说明。
如图所示，在第二实施例中，小截面段2的左侧表面和右侧表面不垂直于底面，改为自上而下向桩体内侧倾斜设定角度，同时，大截面段3的左侧表面和右侧表面也不垂直于底面，改为自上而下向桩体内侧倾斜设定角度。
如此，在俯视图上，小截面段2的上边沿2-1和下边沿2-2(虚线所示)不再重合，其下边沿2-2的垂向投影位于上边沿2-1垂向投影的内侧，同理，大截面段3的上边沿3-1和下边沿3-2(虚线所示)也不再重合，其下边沿3-2的垂向投影位于上边沿3-1垂向投影的内侧。
以第一实施例为基础，可以在同一左凸起部5上形成两个前后对称的上述侧向过渡面4(见图7)，也可以以第二实施例为基础，在同一左凸起部5上形成两个前后对称的上述侧向过渡面4(见图8)，从而获得第三、第四以及更多的实施例。
请参考图9、图10，图9为本发明第五实施例公开的变截面预制方桩的结构示意图；图10为图9所示变截面预制方桩的俯视图。
本实施例中，与第二实施例相同的部分，给予相同的附图标记，并省略相同的文字说明。
如图所示，在第二实施例的基础上，桩体1的右侧面也间隔设置有三个凸出于桩体的右凸起部6，桩体1左侧面的凸起部5与右侧面的凸起部6镜像对称。
镜像对称的左凸起部5与右凸起部6，使得变截面预制方桩在沉桩进入土体时，能够使桩身受力更加均匀，以保持桩身以竖直状态进入土体。
请参考图11，图11为本发明第六实施例公开的变截面预制方桩的结构示意图。
本实施例中，与第三实施例相同的部分，给予相同的附图标记，并省略相同的文字说明。
如图所示，在第三实施例的基础上，桩体1的两端形成有大截面段3，位于两端的大截面段3的横截面与位于中间的大截面段3的横截面基本相同。此结构设计，可以有效提高桩身的桩端承载力，同时提高桩端的抗击 打能力，可以将桩端承载力、压桩力、侧摩擦阻力平衡在最优的情形。
本实施例与第三实施例相比，不仅在打桩时能够受力均匀，保证竖直进入土体，还能有效提高桩段承载力。
请参考图12，图12为本发明第七实施例公开的变截面预制方桩的结构示意图。
本实施例中，与第三实施例相同的部分，给予相同的附图标记，并省略相同的文字说明。
如图所示，在第三实施例的基础上，桩体1的顶面设置有三个凸出于桩体的上凸起部7，桩体1的底面设置有三个凸出于桩体的下凸起部8。
与第三实施例相比，本实施例的变截面预制方桩增加了上凸起部7与下凸起部8，进一步提高了桩身的抗弯强度。另一方面，进一步的增大了与土体的接触面积，提高了侧摩擦阻力，而且，左凸起部5、右凸起部6与下凸起部8，左凸起部5、右凸起部6与上凸起部7均匀过渡，便于制造，结构紧凑，力学性能好。
在本实施例中，上述结构设计，使得各凸起部形成一个闭合的环形，使得变截面预制方桩的整体性加强，也达到了最优的桩身抗弯性能，同时凸起部的强度得到一定加强，抗破碎能力进一步提高。
请参考图13至图16，图13为本发明第八实施例公开的变截面预制方桩的结构示意图；图14为图13的局部放大图；图15为图14的仰视图；图16为图13所示变截面预制方桩的侧视图。
本实施例中，与第七实施例相同的部分，给予相同的附图标记，并省略相同的文字说明。
如图所示，在第七实施例的基础上，桩体1的两端形成有大截面段3，位于两端的大截面段3的横截面与位于中间的大截面段3的横截面基本相同，相对于小截面段2，在周向上具有左凸起部5、右凸起部6、上凸起部7和下凸起部8。
此结构设计，可以有效提高桩身的桩端承载力，同时提高桩端的抗击打能力，可以将桩端承载力、压桩力、侧摩擦阻力平衡在最优的情形。
桩体1两端的大截面段3的长度大于中间部分的大截面段3长度，桩两头的大截面段3长度大约为中间部分的大截面段3长度的2倍～6倍， 以提高桩端结构强度和抗击打性能。
本实施例与第七实施例相比，不仅在打桩时能够受力均匀，保证竖直进入土体，还能有效提高桩段承载力。
以第八实施例为基础，通过改变桩体大截面段3上下边沿的形状，可以获得更多的实施例。例如，变截面预制方桩的底部边沿具有斜面倒角(见图17、图18)，或者，变截面预制方桩的顶部边沿圆滑过渡，即倒圆角(见图19图20)，或者，变截面预制方桩的顶部和底部边沿均具有斜面倒角(见图21、图22)，又或者，变截面预制方桩的顶部边沿具有斜面倒角、底部边沿圆滑过渡(见图23、图24)。
另外，如果在图11所示的第六实施例的基础上，省去位于中间部分的大截面段3，仅保留位于两端的大截面段3，同时将桩体的长度缩短，则可以得到如图25所示的实施例，或者，仅保留位于中间部分的一个大截面段3，从而获得如图26所示的实施例，以及在图25和图26的基础上，进一步在大截面段3增加上凸起部7和下凸起部8后获得的其他实施例。这些实施例中的桩体1长度虽然较短，但可以通过对接多根桩体1的方式相互连接为尺寸较长的预制桩，进而达到与上述其他实施例基本相同的使用效果。
请参考图27至图30，图27为本发明第十一实施例公开的变截面预制方桩的结构示意图；图28为图27所示变截面预制方桩的侧视图；图29为图27所示变截面预制方桩的仰视图；图30为图29中C部位的局部放大图。
本实施例中，与第八实施例相同的部分，给予相同的附图标记，并省略相同的文字说明。
如图所示，在第八实施例的基础上，其两个小截面段2的侧向过渡面4在前后方向上对称，下面以位于前侧的一个小截面段2为例，对其侧向过渡面4进行说明。
此小截面段2具有位于前部的第一过渡面4-1和位于后部的第二过渡面4-2，其中，第一过渡面4-1的前边沿4-1-1和后边沿4-1-2相平行，且自上而下向前倾斜；第二过渡面4-2的前边沿4-2-1自上而下向后倾斜，第二过渡面4-2的后边沿4-2-2自上而下向前倾斜，两者并不平行，两者的侧 向投影形成上大下小的梯形的腰线。
从仰视图可见，其第二过渡面4-2的上边沿4-2-3的垂向投影位于第二过渡面4-2的下边沿4-2-4的垂向投影的外侧。如果将任意两个水平面与第二过渡面4-2的相交的线做垂向投影，则第二过渡面4-2与第一水平面的相交线的垂向投影将位于第二过渡面4-2与第二水平面的相交线的垂向投影的外侧，其中，第一水平面为任意两个水平面中位于上方的水平面，第二水平面为任意两个水平面中位于下方的水平面，而且，第二过渡面4-2与第一水平面的相交线的垂向投影的延长线和第二过渡面4-2与第二水平面的相交线的垂向投影的延长线会相交于一点。
请参考图31，图31为桩体上所形成的(a)～(g)类型的侧向过渡面的集中展示示意图。
如图所示，在其他实施例中，小截面段2的侧向过渡面4还可以有各种不同的形式。
图中所示的(a)类型的侧向过渡面4中的第一过渡面4-1为平面，其前边沿4-1-1和后边沿4-1-2相平行，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度保持恒定，在前面的实施例中已经做过相应的介绍。
图中所示的(b)类型的侧向过渡面4中的第一过渡面4-1为扭曲面，其前边沿4-1-1的侧向投影自上而下向前倾斜，后边沿4-1-2的侧向投影自上而下向后倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变大。
图中所示的(c)类型的侧向过渡面4中的第一过渡面4-1为扭曲面，其前边沿4-1-1的侧向投影自上而下向前倾斜，后边沿4-1-2的侧向投影保持竖直，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变大。
图中所示的(d)类型的侧向过渡面4中的第一过渡面4-1为扭曲面，其前边沿4-1-1的侧向投影保持竖直，后边沿4-1-2的侧向投影自上而下向后倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变大。
图中所示的(e)类型的侧向过渡面4中的第一过渡面4-1为扭曲面，其前边沿4-1-1的侧向投影自上而下向后倾斜，后边沿4-1-2的侧向投影自 上而下向前倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变小。
图中所示的(f)类型的侧向过渡面4中的第一过渡面4-1为扭曲面，其前边沿4-1-1的侧向投影保持竖直，后边沿4-1-2的侧向投影自上而下向前倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变小。
图中所示的(g)类型的侧向过渡面4中的第一过渡面4-1为扭曲面，其前边沿4-1-1的侧向投影自上而下向后倾斜，后边沿4-1-2的侧向投影保持竖直，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变小。
上述(a)～(g)类型的第一过渡面4-1与水平面的相交线为直线。
请参考图32，图32为桩体上所形成的(h)～(n)类型的侧向过渡面的集中展示示意图。
如图所示，在其他实施例中，小截面段2的侧向过渡面4还可以有各种不同的形式。
图中所示的(h)类型的侧向过渡面4中的第一过渡面4-1为内凹面，具体可以是圆柱面或椭圆柱面，其前边沿4-1-1和后边沿4-1-2相平行，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下保持恒定。
图中所示的(i)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影自上而下向前倾斜，后边沿4-1-2的侧向投影自上而下向后倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变大。
图中所示的(j)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影自上而下向前倾斜，后边沿4-1-2的侧向投影保持竖直，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变大。
图中所示的(k)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影保持竖直，后边沿4-1-2的侧向投影自上而下向后倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变大。
图中所示的(l)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影保持竖直，后边沿4-1-2的侧向投影自上而下向前倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变小。
图中所示的(m)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影自上而下向后倾斜，后边沿4-1-2的侧向投影自上而下向前倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变小。
图中所示的(n)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影自上而下向后倾斜，后边沿4-1-2的侧向投影保持竖直，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变小。
上述(h)～(n)类型的第一过渡面4-1与水平面的相交线为向内凹进的弧线。
请参考图33，图33为桩体上所形成的(o)～(u)类型的侧向过渡面的集中展示示意图。
如图所示，在其他实施例中，小截面段2的侧向过渡面4还可以有各种不同的形式。
图中所示的(o)类型的侧向过渡面4中的第一过渡面4-1为外凸面，具体可以是圆柱面或椭圆柱面，其前边沿4-1-1和后边沿4-1-2相平行，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下保持恒定。
图中所示的(p)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影自上而下向后倾斜，后边沿4-1-2的侧向投影自上而下向前倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变小。
图中所示的(q)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影保持竖直，后边沿4-1-2的侧向投影自上而下向前倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变小。
图中所示的(r)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭 曲面，其前边沿4-1-1的侧向投影自上而下向后倾斜，后边沿4-1-2的侧向投影保持竖直，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变小。
图中所示的(s)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影自上而下向前倾斜，后边沿4-1-2的侧向投影自上而下向后倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变大。
图中所示的(t)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影保持竖直，后边沿4-1-2的侧向投影自上而下向后倾斜，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变大。
图中所示的(u)类型的侧向过渡面4中的第一过渡面4-1为锥面或扭曲面，其前边沿4-1-1的侧向投影自上而下向前倾斜，后边沿4-1-2的侧向投影保持竖直，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度自上而下逐渐变大。
上述(o)～(u)类型的第一过渡面4-1与水平面的相交线为向外凸出的弧线。
请参考图34，图34为桩体上所形成的(v)～(w)类型的侧向过渡面的集中展示示意图。
如图所示，在其他实施例中，小截面段2的侧向过渡面4还可以有各种不同的形式。
图中所示的(v)类型的侧向过渡面4中的第一过渡面4-1为外凸面，其前边沿4-1-1和后边沿4-1-2呈相平行的弧形，自上而下向前弯曲，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度保持恒定。
图中所示的(w)类型的侧向过渡面4中的第一过渡面4-1为内凹面，其前边沿4-1-1和后边沿4-1-2呈相平行的弧形，自上而下向前弯曲，从侧面观察时，前边沿4-1-1和后边沿4-1-2之间的宽度保持恒定。
虽然，图31至图34示出的位于中间的大截面段3仅单边形成有改进之后的第一过渡面4-1，但可以理解，对于每一个位于中间的大截面段3而言，其两边的侧向过渡面4均可以采用如图35所示的的对称式结构。此 外，位于中间的大截面段3两边的侧向过渡面4还可以是以上任意两种不同类型的侧向过渡面。
预制变截面方桩在厂房由钢筋混凝土预制成型，预制桩对接完成后在接桩处易产生间隙，因而地下酸、碱腐蚀性物质易从间隙位置进入接桩处腐蚀金属连接件，为解决这一技术问题，可采用下述实施例中的方案。
由于在这些实施例中，将主要介绍变截面预制方桩的端部结构和内部的钢筋结构，为简便起见，图中所示的变截面预制方桩采用了简略画法，未示出大截面段、小截面段以及侧向过渡面等部位，这样的省略并不会影响本领域技术人员理解和再现本发明技术方案。
请参考图36，图36为本发明第十二实施例公开的变截面预制方桩的安装结构示意图。
如图所示，本实施例提供一种变截面预制方桩，该变截面预制方桩为在工厂预制的混凝土构件，其内部通常有若干钢筋构成的骨架，且桩端面19上对应钢筋间隔设置有多个连接孔9，连接孔9内安装有机械连接件14，用于与其他其他外部物体连接，从而实现连续的应力传递，提高混凝土预制构件间的连接强度和可靠性。
本实施例中，外部物体为混凝土构件，如承台、地基等；其中，机械连接件14为本领域常用的机械连接件(如专利文献CN201510649253.6、CN201510314380.0等公开的连接件)。
具体的，预制桩的至少一桩端面19具有凹槽11，用于至少部分容纳存储有粘性物质12的存储块10，当桩端面19抵接外部物体时，存储块10受压释放粘性物质12，粘性物质12溢出凹槽11以分隔连接孔9和最靠近连接孔的桩端面19边缘，进而保护机械连接件14，防止灰尘、泥沙、水等经过桩端面19与外部物体间的间隙进入机械连接件14中，进而腐蚀机械连接件14。
本实施例中，预制桩的上端面和下端面分别设置有凹槽11，如图36所示；为使粘性物质12能够均匀的对所有连接孔9内的机械连接件14进行保护，将凹槽11置于预制桩的桩端面19的中心处，且凹槽11的形状可以根据预制桩的桩端面19的形状来进行设置，可以为圆形、环形、矩形或正多边形等；凹槽11也可以为环形，环绕所有连接孔9或者每个连接孔9都环 绕有一个凹槽11，将连接孔9与桩端面19的边缘隔开，如图37-38所示；由于粘性物质12具有流动性，其被挤压溢出凹槽11后可以沿着桩端面19流动，环形的凹槽11也可以只环绕部分连接孔9，或只有部分连接孔9上分别环绕有一个环形凹槽11；当桩端面19具有多个凹槽11时，可以按照上述凹槽11的形状和位置进行组合设置，如图39-40所示，当然，凹槽11也可以是其他的形状和其他的位置以及组合方式，并不限于本实施例示出的情况。
作为优选的技术手段，为保证凹槽11内能稳定放置存储块10，且存储块10能够被压缩并在粘性物质12溢出凹槽11后，凹槽11内能够存储有足量的粘性物质12，将凹槽11深度设置为大于预制桩直径的0.5％且小于存储块10的高度。这样结构的设置，在预制桩由于生产误差而产生桩端面19倾斜时，凹槽11可以给置于凹槽内的存储块10以足够的阻挡面，防止存储块10倾倒。
请参考图41、图42，图41为本发明第十三实施例公开的变截面预制方桩的接桩过程示意图；图42为图41中变截面预制方桩接桩完成状态示意图。
本实施例中，与实施例十二相同的部分，给予相同的附图标记，并省略相同的文字说明。
本实施例提供一种接桩结构，包括粘性物质12、至少两条依次竖向对接的预制桩和位于相邻两条预制桩之间且存储有粘性物质的至少一个存储块10；且相邻两条预制桩中至少一条为实施例一提供的预制桩，相邻两条依次竖向对接的预制桩分别为上节预制桩和下节预制桩，压缩存储块10可释放粘性物质12以消除和/或填充相邻两条预制桩的接桩端面之间的间隙。
上节预制桩的下端面和下节预制桩的上端面分别开设有凹槽11，两预制桩上凹槽11的位置一一对应且形状相适配，两预制桩上凹槽11的形状也可以不适配且两预制桩上凹槽11轴向上重合的空间可以容纳存储块10，为方便接桩后存储块10完全置于凹槽11中，存储块10被压缩后能够达到的最小厚度小于或等于对应的两个凹槽11深度之和；当然，对应的凹槽11的形状也可以不相适配或不对应，为保证接桩后存储块10完全置于凹 槽11中，存储块10被压缩后能够达到的最小厚度小于或等于其所在凹槽11的深度；作为另一种优选的方案，只在上节预制桩的下端面和下节预制桩的上端面中任一个桩端面19上设置有凹槽11，为方便接桩后存储块10完全置于凹槽11中，存储块10被压缩后能够达到的最小厚度小于或等于凹槽11深度；当然，也可以根据实际情况对两预制桩的端面上是否有凹槽11以及凹槽11的位置进行设置，可以是其他的位置以及组合方式，并不限于本实施例示出的情况；存储块10为弹性吸水性材料，例如海绵等，具有较好的弹性及吸水性，可以吸附并存储大量的粘性物质12，粘性物质12一般为环氧树脂或改性环氧树脂等能够流动且具有固化性的材料，当上节预制桩与下节预制桩的接桩端面相互靠近直至抵接的过程中，存储块10受到上节预制桩与下节预制桩的挤压力而被压缩，如图41所示，粘性物质12从存储块10中被挤压出并溢出凹槽11进而铺满接桩端面19，隔绝桩端面19，防止其与外界的空气、水或砂石等接触，对预制桩端面进行密封和防腐保护；存储块10也可以是由柔性材料制成的胶囊，内部灌装有一定量的粘性物质12，当受到接桩端面19的挤压时，存储块10破裂，粘性物质12从上述破裂的缝隙中流出，或者存储块10上具有小孔，在受压时，小孔被撑大，粘性物质12从小孔中被挤出。
采用上述结构，省去了人工涂抹粘性物质12的工序，如图41所示，将上节预制桩起吊并与下预制桩对齐后，在机械连接件中注满粘性物质12，并将蘸满粘性物质12或预先制好的存有粘性物质12的存储块10放入凹槽11中，当存储块10存储的粘性物质12达到一定量时，还可以进一步省略向机械连接件14中注入粘性物质12的步骤，存储块10中的粘性物质12通过桩端面19流入并注满机械连接件14，方便快捷，提高了工作效率；同时，由于存储块10的体积为一个定值，即其内部存储的粘性物质12也为定值，实现了粘性物质12的定量使用，防止了操作不当造成粘性物质12浪费，节约成本；上节预制桩下压，存储块10中的粘性物质12受到挤压流出，并沿桩端面19流动；继续下压直至接桩端面贴合，存储块10被完全压缩于凹槽11中，如图42所示，此时，接桩完成；由于存储块10的弹性作用，使其在被压缩后与凹槽11的内壁紧贴，且存储块10中仍具有部分粘性物质12，当粘性物质12固化后，将上预制桩与下节预制桩连 接成一体，保证了小应变检测的合格率，提高了预制桩的接桩性能。
请参考图43、图44、图45，图43为本发明第十四实施例公开的变截面预制方桩的接桩结构示意图；图44为图43中变截面预制方桩接桩完成状态示意图；图45为图43中D处结构放大图。
本实施例中，与实施例十三相同的部分，给予相同的附图标记，并省略相同的文字说明。
与实施例十三相比，本实施例的接桩结构还包括耐腐蚀密封圈15，密封圈15套设于相邻两条竖向对接的预制桩的连接处；在接桩前将密封圈15套设在靠近桩端面19的桩身上，再进行两条预制桩的对接，接桩完成后，拖动密封圈15，将其移动至两预制桩端面贴合处并将其包裹住；由于密封圈15具有一定弹性，套设完成后，密封圈15压紧在预制桩上，对桩端面19贴合处进行密封，防止粘性物质12未凝固而流出，减少了粘性物质12的损失。
进一步的，预制桩的桩端直径小于桩身直径，密封圈15的厚度小于或等于桩身直径与桩端直径之差的1/2，密封圈15的宽度小于或等于桩端的长度的2倍，以保证密封圈15不凸出于桩身，在进行打桩时泥土不会将密封圈15推离原始位置；优选的，为方便密封圈15的安装，在桩端与桩身之间设置有平滑过渡部18。
请参考图46、图47、图55、图56，图46为本发明第十五实施例公开的变截面预制方桩的刚性骨架的结构示意图；图47为图46所示刚性骨架的端部视图；图55为辅助箍筋的结构示意图；图56为刚性网罩的结构示意图；
如图所示，本实施例中的变截面预制方桩的桩用刚性骨架，包括：由多根主筋21间隔排列且环绕形成有预留空腔的预制桩用刚性骨架，和箍紧固定所述主筋骨架的骨架箍筋22，主筋骨架的端部套有加强预制桩结构强度的刚性网罩26和/或刚性网片23，主筋骨架的端部由辅助箍筋24箍紧固定，且辅助箍筋24的间距小于或等于骨架箍筋的间距。
具体的说，在主筋骨架的端部增加刚性网罩26，同时在主筋骨架端部外围缠绕辅助箍筋24，箍紧刚性网罩26和主筋21，可以防止在制作混凝土预制桩时，泵送混凝土将主筋骨架端部的主筋21冲击炸开，保护主筋骨架端部结构，也可以防止打桩时主筋21受冲击炸开，加强混凝土预制桩的 端部结构强度。若辅助箍筋离主筋21间距较大则没有防止主筋骨架炸开的作用，所以辅助箍筋24需要紧贴主筋21。并且通过限制辅助箍筋24之间的间距可以更好的加强主筋骨架的结构强度。优选方案，预制桩用刚性骨架为钢筋笼，骨架箍筋和辅助箍筋为螺旋箍筋，刚性网罩26为钢筋网罩。
优选方式，辅助箍筋24和刚性网罩26连接固定，且辅助箍筋24位于刚性网罩26的外部。将刚性网罩26套设在主筋骨架的端部后，再将辅助箍筋24箍住刚性网罩26，可以使主筋骨架能够承受更大的锤击力，避免辅助箍筋24松散开。
如图46和图54所示，所述刚性网罩26包括若干沿主筋骨架长度方向依次间隔排列的环筋26-1和若干连接固定各环筋26-1的轴向筋26-2，轴向筋26-2平行于主筋21。优选方式，轴向筋26-2沿环筋26-1内侧周向固定连接，可以保证刚性网罩26受力均匀。
在主筋骨架端部套设刚性网罩26，可以与辅助箍筋24共同箍住主筋骨架的端部，使主筋骨架的主筋21更不易炸开。优选，刚性网罩26可以是钢筋网罩。
刚性网片23设置于主筋骨架的端部且沿所述预留空腔的长度方向间隔配置。可以加强混凝土预制桩端部的结构强度和抗锤击能力，防止在沉桩时，混凝土预制桩端部被打爆。在本实施例中，刚性网片23可以单独设置，或者刚性网罩26也可以单独设置，或者可以将刚性网片23和刚性网罩26一同设置。
刚性网片23包括若干根交叉连接固定的加强条筋23-1，刚性网片23的端部与辅助箍筋24和/或主筋骨架固定连接。刚性网片23呈格栅状，既可以加强混凝土预制桩端部的强度，又可以保证在制作混凝土预制桩时，混凝土能充分包裹住条筋23-1，保证受力均匀，并且刚性网片23的端部可以与辅助箍筋24连接，也可以与主筋21连接，或者与辅助箍筋24和主筋21连接，保证刚性网片23的稳定连接。
具体的说，刚性网片23所在平面与轴向筋26-2的中轴线垂直。将刚性网片23垂直于轴向筋26-2依次设置在刚性网罩26上，将预留空腔在长度方向上分隔成若干个小空间，可以使混凝土预制桩端部的混凝土更加紧密。
优选方式，将刚性网片23连接在刚性网罩26上，再套入主筋骨架端部，可以将刚性网片23预先连接在刚性网罩26上形成一体式结构，使刚性网片23的放置更加简便。至少有一个刚性网片23与刚性网罩26的端部连接，使刚性网罩26具有挡面，加强刚性网罩26端部结构强度，刚性网片23在刚性网罩26上的连接形式，可以是刚性网片23均与环筋26-1连接，或者是刚性网片23均与轴向筋26-2连接，或者是部分刚性网片23与环筋26-1连接，部分刚性网片23与轴向筋26-2连接。
本实施例的工作原理：在预制时用骨架箍筋22箍紧主筋21，形成主筋骨架，同时将刚性网片23连接在刚性网罩26上，再将刚性网罩26套至主筋骨架的端部，最后用辅助箍筋24箍紧刚性网罩26和主筋21。可以防止在制作混凝土预制桩时，泵送混凝土将主筋骨架端部的主筋21冲击炸开，保护主筋骨架端部结构，同时加强混凝土预制桩的端部结构强度和抗锤击力，可以防止沉桩时，混凝土预制桩端部爆开。
请参考图48、图49，图48为本发明第十六实施例公开的变截面预制方桩的刚性骨架的结构示意图；图49为图48所示刚性骨架的端部视图。
在本实施例中，与实施例十五相同的部分，给予相同的附图标记，并省略相同的文字说明。
相对于实施例十五，本实施例的不同之处在于：主筋21端部设有连接螺母25，所述辅助箍筋24至少连接固定其中一个连接螺母25。预制桩之间通过连接螺母25和插杆连接，所以在主筋21的顶端设置连接螺母25，若辅助箍筋24离连接螺母25间距较大则没有防止主筋骨架炸开的作用，所以辅助箍筋24需要至少连接固定一个连接螺母25，从而防止连接螺母25受锤击而散开，导致预制桩之间的连接移位。
请参考图50、图51，图50为本发明第十七实施例公开的变截面预制方桩的刚性骨架的结构示意图；图51为图50所示刚性骨架的端部视图。
本实施例中，与实施例十五相同的部分，给予相同的附图标记，并省略相同的文字说明。
相对于实施例十五，本实施例的不同之处在于：刚性网片23所在平面与轴向筋26-2的中轴线平行。将刚性网片23平行于轴向筋26-2依次设置在刚性网罩26上，将预留空腔在宽度方向或高度方向上分隔成若干个小空 间，从而使混凝土预制桩端部的混凝土更加紧密。
优选方式，刚性网片23在刚性网罩26上的连接形式，可以是刚性网片23相对的两个端部连接在刚性网罩26上。
请参考图52、图53、图57，图52为本发明第十八实施例公开的变截面预制方桩的刚性骨架的结构示意图；图53为图52所示刚性骨架的端部视图；图57为C型套箍的结构示意图。
本实施例中，与实施例十五相同的部分，给予相同的附图标记，并省略相同的文字说明。
相对于实施例十五，本实施例的不同之处在于：主筋骨架端面还设有若干C型套箍27，且C型套箍27的开口朝向预留空腔的中间段。
在上述结构中，C型套箍27可以使主筋骨架的端部形成一个挡面，使主筋骨架的端部结构更加稳定，加强混凝土预制桩端面的结构强度。
具体的说，C型套箍7横向或纵向依次均匀排列设置在主筋骨架的预留空腔内；或者，C型套箍7交叉设置在主筋骨架的预留空腔内；所述C型套箍7与辅助箍筋24或/和刚性网罩26固定连接。C型套箍27采用以上的布置形式形成挡面可以加强混凝土预制桩端面的结构强度，同时可以与辅助箍筋24一起箍紧刚性网罩26。作为优选，C型套箍27交叉布置在主筋骨架的端面。当然，在实施例十五中的刚性网片23的端部也可以与C型套箍27连接。
优选方式，刚性网片23的端部与刚性网罩26连接固定，C型套箍7与刚性网罩26的端部连接固定，且C型套箍27位于刚性网罩26的内部。可以将刚性网片23连接在C型套箍27上，再连接在刚性网罩26上，形成一体式结构，再套入主筋骨架端部，使刚性网片23的放置更加简便。
本实施例的工作原理：在预制时用骨架箍筋22箍紧主筋21，形成主筋骨架，同时先将C型套箍7上连接在刚性网罩26的端部上形成挡面，再将刚性网片23连接在刚性网罩26上，然后将刚性网罩26套至主筋骨架的端部，最后用辅助箍筋24箍紧刚性网罩26和主筋21。可以防止在制作混凝土预制桩时，泵送混凝土将主筋骨架端部的主筋21冲击炸开，也可以防止刚性网片被泵送混凝土冲击，脱出主筋骨架的预留空腔，保护主筋骨架端部结构，并且使主筋骨架结构更稳定，并且能使混凝土预制桩端部的 混凝土更加紧密，从而加强混凝土预制桩的端部结构强度和抗锤击能力。
在上述实施例的基础上，在小截面段2的横截面上，小截面段2的横截面面积为S1，钢棒横截面面积总和为S2，S2占S1的比值至少为0.5％～0.15％，受力筋占比高，提高桩身结构强度和抗拔强度。此外，桩两端螺旋箍筋加密区的长度大于端部大截面段3的长度，桩两端螺旋箍筋加密区的密度为普通区的1.5-3倍，以提高桩端结构强度和抗击打性能；钢棒间距大于等于50mm，以方便浇筑或泵送混凝土时，粗骨料(即石子)能够均布；桩端部增加钢性网罩26和钢筋网片23，可提高桩端部抗锤击能力，避免爆桩引起的连接件或受力筋裸露在地下酸、碱腐蚀性物质中。
如果侧向过渡面4为内凹面或外凸面，则由于圆滑过渡，其前边沿或后边沿的痕迹将不是十分明显，人眼观察可能难以分辨，此时，可以沿侧向过渡面4的边界做辅助线来界定其前边沿或后边沿所在的位置。
本发明要求保护的变截面预制方桩包含变截面实心方桩和变截面空心方桩，对于变截面实心方桩而言，既可以可以采用U形模具进行生产，也可以采用沿对角线开合的闭合模具进行生产。当采用U形模具生产时，本发明十分有利于进行脱模，可避免暴力拆模造成混凝土保护层开裂或者有脱落风险。
各实施例之间的技术方案可以相互结合，但应该是以本领域普通技术人员能够实现为基础。若技术方案的结合出现相互矛盾或无法实现时，应当认为这种技术方案的结合不存在，也不在本发明要求的保护范围之内。
以上对本发明所提供的混凝土变截面预制方桩进行了详细介绍。本文中应用了具体个例对本发明的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本发明的核心思想。应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以对本发明进行若干改进和修饰，这些改进和修饰也落入本发明权利要求的保护范围内。

Claims (20)

  1. 一种混凝土变截面预制桩，包括沿纵向交替排列有大截面段和小截面段的桩体，所述大截面段和小截面段的横截面大体呈矩形；所述大截面段与相邻的所述小截面段的侧表面之间形成有侧向过渡面；至少部分数量的所述侧向过渡面具有在侧向投影上偏离竖直方向的前边沿和/或后边沿，且该侧向过渡面与第一水平面的相交线的垂向投影位于该侧向过渡面与第二水平面的相交线的垂向投影的外侧；所述第一水平面为任意两个水平面中位于上方的水平面，所述第二水平面为任意两个水平面中位于下方的水平面；所述小截面段的一个或两个侧表面垂直于所述小截面段的底面或者自上而下向桩体内侧倾斜设定角度。
  2. 根据权利要求1所述的混凝土变截面预制桩，其特征在于，所述侧向过渡面在侧向投影上偏离竖直方向的前边沿和/或后边沿为倾斜的边沿或弯曲的边沿。
  3. 根据权利要求1或2所述的混凝土变截面预制桩，其特征在于，位于两端之间的所述大截面段的侧表面的前边沿和后边沿为竖直边沿，其面宽自上而下保持恒定；或者，位于两端之间的所述大截面段的侧表面的前边沿和/或后边沿在侧向投影上偏离竖直方向，其面宽自上而下变大或变小。
  4. 根据权利要求1或2所述的混凝土变截面预制桩，其特征在于，所述侧向过渡面包括位于小截面段前部的第一过渡面和位于小截面段后部的第二过渡面，所述第一过渡面的后边沿自上而下向前倾斜或弯曲；和/或，所述第二过渡面的前边沿自上而下向后倾斜或弯曲。
  5. 根据权利要求1或2所述的混凝土变截面预制桩，其特征在于，所述侧向过渡面包括位于小截面段前部的第一过渡面和位于小截面段后部的第二过渡面，所述第一过渡面的前边沿自上而下向前倾斜或弯曲；和/或，所述第二过渡面的后边沿自上而下向后倾斜或弯曲。
  6. 根据权利要求1所述的混凝土变截面预制桩，其特征在于，所述侧向过渡面为平面，其前边沿平行于后边沿，面宽自上而下保持恒定，或者，所述侧向过渡面为平面，其前边沿与后边沿不平行，面宽自上而下变大或变小；或者，
    所述侧向过渡面为曲面，其前边沿平行于后边沿，面宽自上而下保持恒定，或者，所述侧向过渡面为曲面，其前边沿与后边沿不平行，面宽自上而下变大或变小。
  7. 根据权利要求6所述的混凝土变截面预制桩，其特征在于，所述侧向过渡面为内凹的曲面、外凸的曲面或扭曲面。
  8. 根据权利要求7所述的混凝土变截面预制桩，其特征在于，所述内凹的曲面包括内凹的弧面或内凹的锥面，所述外凸的曲面包括外凸的弧面或外凸的锥面。
  9. 根据权利要求1所述的混凝土变截面预制桩，其特征在于，所述侧向过渡面与第一水平面的相交线的垂向投影的延长线和该侧向过渡面与第二水平面的相交线的垂向投影的延长线相交。
  10. 根据权利要求1所述的混凝土变截面预制桩，其特征在于，所述桩体具有桩端面，至少一桩端面具有凹槽和多个间隔布置的连接孔，所述凹槽用于至少部分容纳存储有粘性物质的存储块，所述凹槽深度小于存储块的初始高度，在预制方桩对接时，压缩所述存储块可释放粘性物质以消除和/或填充相对接预制方桩的接桩端面间隙。
  11. 根据权利要求10所述的混凝土变截面预制桩，其特征在于，所述容纳槽的槽深大于等于1mm、槽宽大于等于1mm，且所述容纳槽距所述连接孔0.5cm以上。
  12. 根据权利要求11所述的混凝土变截面预制桩，其特征在于，所述容纳槽的槽深为2mm-20mm。
  13. 根据权利要求10所述的混凝土变截面预制桩，其特征在于，至少一个所述凹槽呈圆形或环形或矩形或正多边形且位于桩端面的中心处；
    和/或，至少一个所述凹槽为环状且环绕所有连接孔；
    和/或，至少一个所述凹槽为环状且环绕部分连接孔；
    和/或，至少一个所述凹槽为环状且环绕单个连接孔。
  14. 根据权利要求1或10所述的混凝土变截面预制桩，其特征在于，其刚性骨架包括：由多根主筋间隔排列且环绕形成有预留空腔的主筋骨架，以及箍紧所述主筋骨架的骨架箍筋；
    其中，所述主筋骨架的端部套有加强预制桩结构强度的刚性网罩和/ 或刚性网片，主筋骨架的端部由辅助箍筋箍紧固定，且辅助箍筋的缠绕间距小于或等于骨架箍筋的缠绕间距。
  15. 根据权利要求14所述的混凝土变截面预制桩，其特征在于，所述辅助箍筋形成箍筋加密区，所述箍筋加密区的长度大于端部大截面段的长度；所述箍筋加密区的缠绕密度为非加密区的1.5-3倍。
  16. 根据权利要求14所述的混凝土变截面预制桩，其特征在于，主筋骨架端面还设有若干开口朝向预留空腔的中部的C型套箍。
  17. 根据权利要求14、15或16所述的混凝土变截面预制桩，其特征在于，所述主筋端部连接有连接螺母，所述辅助箍筋至少连接固定其中一个连接螺母。
  18. 根据权利要求16所述的混凝土变截面预制桩，其特征在于，所述C型套箍横向或纵向依次间隔排列设置在主筋骨架的预留空腔内；和/或，C型套箍交叉设置在主筋骨架的预留空腔内；所述C型套箍与辅助箍筋或/和刚性网罩固定连接。
  19. 根据权利要求14所述的混凝土变截面预制桩，其特征在于，辅助箍筋和刚性网罩连接固定，且刚性网罩位于辅助箍筋的内部；
    或者，所述刚性网罩包括若干沿主筋骨架长度方向依次间隔排列的环筋以及若干连接固定各环筋的轴向筋，其中，轴向筋平行于主筋；
    或者，所述刚性网片设置于主筋骨架的端部且沿所述预留空腔的长度方向间隔配置。
  20. 根据权利要求14所述的混凝土变截面预制桩，其特征在于，所述桩体两端的大截面段长度大于中间部分的大截面段长度，所述桩体两端的大截面段长度大约为中间部分的大截面段长度的2倍～6倍；
    和/或，在所述小截面段的横截面上，所述小截面段的横截面面积为S1，钢棒横截面面积总和为S2，S2占S1的比值至少为0.5％～0.15％。
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