WO2023010631A1

WO2023010631A1 - Deepwater group pile foundation

Info

Publication number: WO2023010631A1
Application number: PCT/CN2021/115223
Authority: WO
Inventors: 肖海珠; 邱远喜; 苑仁安; 高宗余; 刘俊锋; 潘韬; 何东升; 李华云; 冯龙兴; 谭国宏; 别业山
Original assignee: 中铁大桥勘测设计院集团有限公司
Priority date: 2021-08-06
Filing date: 2021-08-30
Publication date: 2023-02-09
Also published as: EP4257753A1; CN113700033A; CN113700033B

Abstract

A deepwater group pile foundation, comprising: multiple drilled piles (100), the cross-sectional shape of pile tops (100a) of the drilled piles (100) being a square provided with an arc chamfer, a first reinforcement cage (103) being pre-embedded at the interior of each pile top (100a), the cross-sectional shape of the first reinforcement cages (103) being the same as the cross-sectional shape of the pile tops (100a), and the first reinforcement cages (103) each comprising multiple first vertical main ribs (103a) arranged at even intervals; a bearing platform (200), the bearing platform (200) being fixed above the drilled piles (100), multiple horizontal steel reinforcing bars (105) being provided in the bottom part of the bearing platform (200), the upper ends of the first vertical main ribs (103a) being vertically inserted into the bearing platform (200), and the horizontal steel reinforcing bars (105) within the width range of the first reinforcement cages (103) each passing through gaps between two adjacent first vertical main ribs (103a); and bottom sealing concrete (300), the bottom sealing concrete (300) being located within the height range of the pile tops (100a) below the bearing platform (200).

Description

A deep water pile group foundation

technical field

The invention relates to the technical field of bridge engineering, in particular to a deep-water pile group foundation.

Background technique

With the rapid development of my country's transportation infrastructure, the construction of cross-sea bridge projects is gradually advancing from the offshore to the deep sea. There are more and more projects, the scale of the project is getting larger, and the construction environment is becoming more and more complex and diverse. Harsh marine environments such as hurricanes, deep water, rapids, and strong swells will bring great challenges to the construction of bridge engineering, especially in the design and construction technology of bridge deep water foundations.

As a commonly used foundation form for deep water foundations, pile group foundations with high caps are widely used in cross-sea bridge projects in my country because of their mature technology, rich construction experience, and relatively low construction risks. Compared with inland river bridges, the main difference of deep-water foundations of sea-crossing bridges is that the hydrological environment and meteorological conditions are more severe. The impact force of the ship. Due to the changeable climate, strong wind, deep water, and high waves at sea, the duration of construction operations allowed for the foundation of cross-sea bridges is relatively short. For pile group foundations with high caps, under the action of horizontal loads, the part with the largest bending moment of the pile foundation often appears at the top of the pile, and the structural strength is controlled by the bending resistance, so a large number of steel bars are required at the top of the pile. In order to reduce the influence of wave currents on pile foundations, reduce erosion at piers, and meet the requirements of drilling construction and hole stability, bridge pile foundations usually adopt circular cross-sections. The main reinforcement of the pile foundation reinforcement cage is evenly arranged in a circular direction and anchored in the cap, while the longitudinal and transverse horizontal reinforcement at the bottom of the pile cap needs to pass through the pile foundation reinforcement cage.

Since the main bars of the reinforcement cage of the pile foundation are evenly arranged in the circular direction, the projection width of the distance between adjacent main bars of the same pile foundation in the longitudinal and transverse directions becomes smaller from the middle to both sides. When the diameter of the horizontal reinforcement is reduced, it is difficult for the horizontal reinforcement at the bottom of the cap to pass through the reinforcement cage smoothly. Especially when the reinforcement cage of the pile foundation is required to be equipped with two turns of main reinforcement due to force requirements, the blind area where the horizontal reinforcement at the bottom of the cap is difficult to pass through the reinforcement cage of the pile foundation is larger.

In the marine environment with harsh wave and current conditions, in order to reduce the wave and current force on the foundation and reduce the size of the foundation, the caps are usually designed as a sharp or round-end contour, and the pile foundations are arranged in a plum blossom shape accordingly. , and the quincunx-shaped pile foundation layout will further increase the width of the blind area where the horizontal reinforcement in the entire cap range is difficult to pass through the pile foundation reinforcement cage. The horizontal reinforcement at the bottom of the cap is usually truncated within the width of the blind zone, which cannot maintain a full length, which is unfavorable to the structural force. Moreover, the spacing of horizontal steel bars on the bottom surface of the entire cap range is uneven, which has a certain adverse effect on the quality of concrete pouring.

At the same time, the corrosion environment of cross-sea bridges is even harsher. In order to ensure the durability of the bridge structure, epoxy reinforcement is often used as reinforcement for the caps. However, the construction requirements of epoxy steel bars are relatively high. In order to avoid the coating of epoxy steel bars being damaged, the main bars at the bottom of the platform are prohibited from scratching with the reinforcement cage of the pile foundation when arranging them. This undoubtedly greatly increases the construction difficulty of the horizontal reinforcement at the bottom of the cap, and also increases the construction period, and the construction quality of the cap is difficult to guarantee. The construction of the horizontal reinforcement at the bottom of the pile foundation cap of a large-scale sea-crossing bridge has always been a difficult problem for the construction unit, especially the problem that the horizontal reinforcement at the bottom of the pile cap is difficult to pass through the pile foundation reinforcement cage smoothly.

Contents of the invention

The embodiment of the present invention provides a deep-water pile group foundation to solve the problem that the horizontal steel bars at the bottom of the pile cap of cross-sea bridges in the related art are difficult to pass through the reinforcement cage of the pile foundation smoothly, and the range of the reinforcement cage of the pile foundation cannot allow the bottom of the pile cap to pass through. The problem of the blind area where the horizontal steel bars pass through.

In the first aspect, a deep-water pile group foundation is provided, which includes: a plurality of bored piles, the bored piles have pile tops, the cross-sectional shape of the pile tops is a square with rounded corners, and the square The four straight sides are respectively parallel to the longitudinal and transverse directions of the entire deep-water pile group foundation, and a first reinforcement cage is pre-embedded inside the pile top, and the cross-sectional shape of the first reinforcement cage is the same as that of the pile top. The first reinforcement cage includes a plurality of first vertical main reinforcements arranged at even intervals; a cap, the cap is fixed above the bored pile, and a plurality of horizontal steel bars are arranged in the bottom of the cap, the cap The upper end of the first vertical main reinforcement is vertically inserted into the cap, and the horizontal reinforcement within the width range of the first reinforcement cage respectively passes through the gap between two adjacent first vertical main reinforcements; The back-sealing concrete is located within the height range of the pile top below the cap.

In some embodiments, the bored pile further includes: a pile body, the pile body is located below the pile top, the cross-sectional shape of the pile body is circular, and a second reinforcement cage is arranged inside the pile body , the cross-sectional shape of the second reinforcement cage is the same as the cross-sectional shape of the pile body, the second reinforcement cage includes a plurality of second vertical main reinforcements arranged at uniform intervals; a transition section, the transition section connects the The top of the pile and the pile body, the cross-sectional shape of the transition section is a square with circular arc chamfers, and the radius of the circular arc chamfers in the cross section of the transition section is along the height direction of the transition section from The top of the transition section becomes larger gradually from the bottom of the transition section, and a plurality of third main reinforcements are pre-embedded in the transition section, and the third main reinforcement connects the first vertical main reinforcement and the second vertical main reinforcement. The straight main reinforcement corresponds to the linear connection one by one.

In some embodiments, the cross section of the pile top is a square with rounded corners, and the width of the square cross section of the pile top is equal to the diameter of the circular cross section of the pile body.

In some embodiments, the height _H2 of the transition section is greater than or equal to the diameter D of the pile body.

In some embodiments, the radius r _z of the arc chamfer of the cross section at any height of the transition section is:

r _z =r ₁ +(D/2-r ₁ )×z/H ₂ ,

In the formula, z is the height of any cross-section in the transition section from the bottom surface of the pile top, _H2 is the height of the transition section, D is the diameter of the pile body, _r1 is the pile top The radius of the rounding of the cross section.

In some embodiments, the bored pile further includes a second steel casing sleeved outside the second reinforcement cage, and the number n ₂ of the second vertical main reinforcement is:

n ₂ ＝4 _* Int([π _* (D-2 _* (t ₂ +δ _average ))]/[4 _* (80+d ₂ + _△ s)]),

In the formula, π is the circumference ratio, D is the diameter of the pile body, _t is the wall thickness of the second steel casing, and δ _is the circumferential centerline of the plane layout of the second vertical main reinforcement and the The average distance between the inner surface of the second steel casing, d ₂ is the diameter of the second vertical main reinforcement, _△ s is the adjustment amount of the second vertical main reinforcement spacing, and the value of _△ s satisfies: 5≤ _△ s ≤120-d ₂ , the unit of each parameter in the formula is millimeter.

In some embodiments, the value range of the height _H1 of the pile top is:

H ₁ ＞γ _w H ₄ [A _c +0.86nr ₁ ^{^2} -nB ^{^2} ]/[4n(B-0.43r ₁ )[τ]+γ _c (A _c +0.86nr ₁ ^{^2} -nB ^{^2} )+W],

In the formula, γ _w is the weight of water, γ _c is the weight of concrete, H ₄ is the height of the bottom surface of the pile top from the construction high water level, A _c is the bottom area of the cap, and B is the pile top The width of the cross-section, r ₁ is the radius of the arc chamfer of the pile top cross-section, n is the number of the bored piles, [τ] is the allowable bond strength between concrete and steel surface, W is The weight of the cap platform construction cofferdam.

In some embodiments, the bored pile further includes a first steel casing sleeved on the outside of the first reinforcement cage, and part of the first vertical main reinforcement along the cross-section of the top of the pile is equal to four sides of the straight section. Spacing arrangement, wherein, the spacing s is:

s=[4(B-2r ₁ )+2π(r ₁ -(t ₁ +f _average ))]/n ₁ ,

In the formula, B is the width of the cross section of the pile top, _r1 is the radius of the arc chamfer of the pile top cross section, π is the circumference ratio, and _t1 is the wall thickness of the first steel casing, f _is the average distance between the circumferential centerline of the planar layout of the first vertical main reinforcement and the inner surface of the first steel casing, and _n is the number of the first vertical main reinforcement in a single circle;

Part of the first vertical main reinforcement along the circular arc chamfering section of the cross-section of the pile top is arranged at equal deflection angles, wherein the size of the deflection angle α is:

α=s/(r ₁ -(t ₁ +f _mean )),

In the formula, s is the distance that the first vertical main reinforcement is arranged along the four-side straight section of the cross-section of the pile top, _r1 is the radius of the arc chamfer of the cross-section of the pile top, and _t1 is the The wall thickness of the first steel casing, f, _is the average distance between the circumferential centerline of the planar layout of the first vertical main reinforcement and the inner surface of the first steel casing.

In some embodiments, the bored pile further includes a first steel casing sleeved outside the first reinforcement cage. When two turns of the first vertical main reinforcement are arranged in the first reinforcement cage, the The value range of the radius _r1 of the arc chamfer of the pile top cross section is:

((340+4d ₁ )/π+t ₁ +f ₂ )≤r ₁ ≤(1400/π+t ₁ +f ₁ ),

In the formula, d ₁ is the diameter of the first vertical main reinforcement, π is the circumference ratio, t ₁ is the wall thickness of the first steel casing, and f ₁ and f ₂ represent the first and second circles respectively. The distance between the circumferential centerline of the plane layout of the vertical main reinforcement and the inner surface of the first steel casing, the units of the parameters in the formula are millimeters.

In some embodiments, the value range of the ratio of the cap thickness _H3 to the pile diameter D is:

H ₃ /D≥1.2.

The beneficial effects brought by the technical solution provided by the invention include:

The embodiment of the present invention provides a deep-water pile group foundation. Since the bored pile has a pile top, the cross section of the pile top is a square with circular arc chamfers, and the four straight sides of the square are respectively parallel to the longitudinal and transverse directions of the entire foundation. And the inside of the bored pile is pre-embedded with a first reinforcement cage, the cross-sectional shape of the first reinforcement cage is the same as the cross-sectional shape of the pile top, the first reinforcement cage includes a plurality of first vertical main reinforcements, and the first vertical main reinforcements It is arranged at even intervals; the cap is fixed above the top of the pile, the upper end of the first vertical main reinforcement is vertically inserted into the cap, and a plurality of horizontal steel bars are arranged at the bottom of the cap, and the horizontal steel bars are connected from two adjacent first vertical bars respectively. The gap between the main bars is passed; the back cover concrete is located within the height of the pile top below the cap. Therefore, the horizontal reinforcing bars at the bottom of the cap can pass through the width range of the first reinforcing cage smoothly, and there is no blind area within the width range of the first reinforcing cage that cannot allow the horizontal reinforcing bars to pass through. All the horizontal steel bars in the caps do not need to be cut off, they are kept in full length, and the spacing of the steel bars is even and uniform, and the density is appropriate. The construction difficulty of the horizontal reinforcement in the cap is reduced, the quality of the concrete pouring of the cap is guaranteed, the force is better, and the construction period of the cap is shortened.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

Fig. 1 is the structural representation of the deep water pile group foundation that the embodiment of the present invention provides;

Fig. 2 is a schematic cross-sectional view of A-A in Fig. 1;

Fig. 3 is a schematic diagram of horizontal steel bars passing through the gap between adjacent first vertical main bars in the deep water pile group foundation provided by the embodiment of the present invention;

Fig. 4 is the front schematic view of the bored pile single pile in the deep water pile group foundation provided by the embodiment of the present invention;

5 is a schematic diagram of a three-dimensional structure of a single bored pile in a deep-water pile group foundation provided by an embodiment of the present invention;

6 is a schematic cross-sectional view of a single bored pile in a deep-water pile group foundation provided by an embodiment of the present invention;

Fig. 7 is a schematic cross-sectional view of B-B in Fig. 4;

Fig. 8 is a schematic diagram of the three-dimensional structure of the first angle of the transition section of the single pile in the deep water pile group foundation provided by the embodiment of the present invention;

Fig. 9 is a schematic diagram of the three-dimensional structure of the second angle of the transition section of the single pile in the deep water pile group foundation provided by the embodiment of the present invention;

Figure 10 is a schematic cross-sectional view of C-C in Figure 6;

Fig. 11 is a structural schematic diagram of the second reinforcement cage in the deep water pile group foundation provided by the embodiment of the present invention;

Figure 12 is a schematic cross-sectional view of D-D in Figure 6;

Fig. 13 is a structural schematic diagram of the reinforcement cage in the transition section of the deep water pile group foundation provided by the embodiment of the present invention;

Figure 14 is a schematic cross-sectional view of E-E in Figure 6;

Fig. 15 is a structural schematic diagram of the first reinforcement cage in the deep water pile group foundation provided by the embodiment of the present invention;

Fig. 16 is a schematic diagram of the layout of vertical and transverse horizontal steel bars at the bottom of the 1/4 cap of the deep-water pile group foundation provided by the embodiment of the present invention.

In the picture:

100, bored pile; 100a, pile top; 100b, transition section; 100c, pile body; 101, steel casing; 101a, first steel casing; 101c, second steel casing; 102, concrete pile body; 103 103a, the first vertical main reinforcement; 103b, the third main reinforcement; 104, the second reinforcement cage; 104a, the second vertical main reinforcement; 105, the horizontal reinforcement;

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The embodiment of the present invention provides a deep-water pile group foundation, which can solve the problem that the horizontal steel bars at the bottom of the cap platform of the cross-sea bridge pile group foundation cannot smoothly pass through the blind area of the pile foundation reinforcement cage.

Referring to Fig. 1 to Fig. 4, Fig. 15 and Fig. 16, a deep water pile group foundation provided by an embodiment of the present invention may include: a plurality of bored piles 100, and the bored piles 100 may have a pile top 100a, The cross-section of the pile top 100a can be a square with arc chamfers. In this embodiment, the four corners of the square cross-section of the pile top 100a are all arc chamfers, and the four straight sides of the square section are respectively connected with the whole deep water group The vertical and horizontal directions of the pile foundation are parallel, and the inside of the bored pile 100 can be pre-embedded with a first reinforcement cage 103. In this embodiment, the first reinforcement cage 103 is welded and fixed by a plurality of first vertical main reinforcements 103a and stirrups. In this way, the first vertical main reinforcement 103a is perpendicular to the cross-section of the bored pile 100, the cross-sectional shape of the first reinforcement cage 103 can be the same as the cross-sectional shape of the pile top 100a, and the first vertical main reinforcement 103a can be evenly spaced. , that is, a part of the first vertical main ribs 103a can be evenly spaced along the four-sided straight segments of the cross-section of the pile top 100a, and the other part of the first vertical main ribs 103a can be respectively arranged along the four circular arc chamfering segments of the cross-section of the pile top 100a Equivalent deflection angles are set, and the first vertical main reinforcement 103a can be arranged with the longitudinal and transverse centerlines of the pile foundation section as the symmetrical axis, and the plane layout of the first vertical main reinforcement 103a of each pile top 100a within the entire foundation range is parallel to each other; The cap 200, the cap 200 can be fixed above the pile top 100a, and the upper end of the first vertical main reinforcement 103a can be vertically inserted into the cap 200. In this embodiment, each bored pile 100 within the entire cap 200 The first vertical main bars 103a are all arranged parallel to each other, and a plurality of horizontal steel bars 105 can be provided at the bottom of the cap 200, and the horizontal steel bars 105 within the width of the first steel cage 103 can be separated from two adjacent first vertical main bars. The gap between 103a passes through; the back-sealing concrete 300, the back-sealing concrete 300 is located within the height range of the pile top 100a below the cap 200. When the first vertical main reinforcement 103a is located within the four-sided straight section of the cross-section of the first reinforcement cage 103, the planar arrangement of the first vertical main reinforcement 103a is parallel to the longitudinal and transverse directions of the entire foundation, and due to the horizontal reinforcement at the bottom of the cap The layout of 105 is also parallel to the longitudinal and transverse directions of the entire foundation, so it is only necessary to set the net distance between two adjacent first vertical main bars 103a to be greater than the diameter of the horizontal steel bar 105 at the bottom of the cap, and the horizontal steel bar 105 can be Smoothly pass through the gap between two adjacent first vertical main bars 103a within the range of the straight line section of the cross section of the first reinforcement cage 103, and there are 2 or 4 first vertical bars in each bored pile 100 on average. The straight main reinforcement 103a is located within the range of the circular arc chamfering section of the cross section of the first reinforcement cage 103, and the horizontal reinforcement bar 105 can also be smoothly moved from within the range of the circular arc chamfering section of the cross section of the first reinforcement cage 103 through partial bending. The gap between two adjacent first vertical main bars 103a passes through, therefore, the horizontal steel bar 105 at the bottom of the cap 200 can pass through the width range of the first reinforcement cage 103 smoothly, and there is no gap within the width range of the first reinforcement cage 103 There is a blind area that cannot allow the horizontal steel bars 105 to pass through. All the horizontal steel bars 105 at the bottom of the cap 200 do not need to be cut off, and can be kept in full length, and the spacing between adjacent horizontal steel bars 105 is even and uniform, and the density is appropriate. The cap 200 The construction difficulty of the horizontal steel bar 105 at the bottom is reduced, the concrete pouring quality of the cap 200 is guaranteed, the force is better, and the construction period of the cap 200 is shortened.

Referring to Fig. 4 to Fig. 11 and Fig. 13, in some embodiments, the bored pile 100 may further include: a pile body 100c and a transition section 100b, the pile body 100c may be located below the pile top 100a, and the transverse direction of the pile body 100c The section can be circular, and the second reinforcement cage 104 can be pre-embedded inside the pile body 100c. The cross-sectional shape of the second reinforcement cage 104 can be the same as the cross-sectional shape of the pile body 100c. Including a plurality of second vertical main reinforcements 104a arranged at uniform intervals, that is, a plurality of second vertical main reinforcements 104a can be arranged at uniform intervals along the ring of the cross section of the second reinforcement cage 104; the transition section 100b can be located between the pile top 100a and the Between the pile bodies 100c, the pile top 100a and the pile body 100c can be connected together through the transition section 100b. The radius of the transition section 100b is constantly changing along the height direction of the transition section 100b. In this embodiment, the radius of the circular arc chamfering of the cross section of the transition section 100b is along the height direction of the transition section 100b, and gradually changes from the top surface of the transition section 100b to the bottom surface of the transition section 100b. A plurality of third main ribs 103b can be pre-embedded in the transition section 100b, and the first vertical main ribs 103a and the second vertical main ribs 104a can be connected linearly in one-to-one correspondence through the third main ribs 103b. Therefore, the cross-section of the pile top 100a of the bored pile 100 can be designed as a square with circular arc chamfers, and the pile body 100c of the bored pile 100 can be designed into a circle, and the square pile top 100a with circular arc chamfers can make The horizontal steel bar 105 at the bottom of the cap 200 smoothly passes through the width range of the first steel cage 103, and the circular pile body 100c can reduce the impact of the seawater wave current on the bored pile 100, reduce the erosion at the pier position, And meet the requirements of drilling construction and hole stability.

8 and 9, in some embodiments, the transition section 100b can be formed by the radius of the circular chamfer of the pile top 100a gradually increasing toward the pile body 100c, so that the transition section 100b has an inclined side surface , the area of the cross section of the transition section 100b gradually becomes smaller from the bottom surface of the pile top 100a to the top surface of the pile body 100c. By setting in this way, the third main rib 103b can be bent without transition to the first The vertical main ribs 103a are linearly connected to the second vertical main ribs 104a in one-to-one correspondence.

Referring to Fig. 7, in some embodiments, the cross section of the pile top 100a can be a square with circular arc chamfers, the width B of the cross section of the pile top 100a can be equal to the diameter D of the cross section of the pile body 100c, The ratio of the width B of the cross-section of the pile top 100a to the diameter D of the cross-section of the pile body 100c can satisfy: B/D=1, that is, the cross-section of the pile top 100a is a circumscribed square of the cross-section of the pile body 100c, and the pile The area of the cross-section of the top 100a is 1.2 times the area of the cross-section of the pile body 100c, and the cross-sectional bending resistance moment of the pile top 100a is 1.7 times that of the cross-section bending resistance moment of the pile body 100c, so when bearing the same load In the case of , the amount of the main reinforcement of the reinforcement cage in the bored pile 100 can be effectively reduced.

Referring to Fig. 4, Fig. 5 and Fig. 7, in some embodiments, the height _H2 of the transition section 100b can be greater than or equal to the diameter D of the pile body 100c, which ensures that the load is between the pile top 100a and the pile body 100c. The transmission is more uniform, and the stress concentration caused by the sudden change of the section of the pile foundation is avoided.

Referring to Fig. 7 to Fig. 9, Fig. 12 and Fig. 14, in some embodiments, the radius r _z of the circular chamfer of the cross section at any height of the transition section 100b can be:

r _z =r ₁ +(D/2-r ₁ )×z/H ₂ ,

In the formula, z can be the height from the bottom surface of the pile top 100a at any cross section in the transition section 100b, and r _z can be the radius of the arc chamfer of the cross section of the transition section 100b at the height z from the bottom surface of the pile top 100a, H ₂ may be the height of the transition section 100b, D may be the diameter of the pile body 100c, and r ₁ may be the radius of the circular chamfer of the cross section of the pile top 100a.

Referring to Fig. 6, in some embodiments, the bored pile 100 can be poured into the steel casing 101 with the reinforcement cage pre-embedded and in the borehole by pouring underwater concrete. In this embodiment, the steel casing 101 is In the shape of a square top and a round body, the underwater concrete is solidified into a concrete pile body 102 , and the concrete pile body 102 is combined with a steel casing 101 to form a bored pile 100 .

Referring to Fig. 10 and Fig. 11, in some embodiments, the bored pile 100 may also include a second steel casing 101c sleeved outside the second reinforcement cage 104, and the second reinforcement cage 104 may have 1 turn or 2 turns. Circle the second vertical main reinforcement 104a, the number of turns of the second reinforcement cage 104 can be equated with the number of turns of the first reinforcement cage 103, the root number of the second vertical main reinforcement 104a of a single circle can be the first vertical main reinforcement 103a of a single circle Root number is equal, and the root number of the second vertical main rib 104a of each single circle can be equal, and the root number _n of the second vertical main rib 104a of single circle can be:

In the formula, π can be the circumference ratio, D can be the diameter of the pile body 100c, _t2 can be the wall thickness of the second steel casing 101c, and δ _is the circumferential centerline of the plane layout of the second vertical main reinforcement 104a and the first The average distance of the inner surface of the second steel casing 101c, when only one second vertical main reinforcement 104a is arranged, δ ₌ δ ₁ , and when two second vertical main reinforcements 104a are arranged, _δ = (δ ₁ +δ ₂ ) /2, δ ₁ and δ ₂ represent the distances between the circumferential centerline of the planar layout of the first and second rounds of second vertical main ribs 104a and the inner surface of the second steel casing 101c, and d ₂ can be the second vertical The diameter of the straight main reinforcement 104a, when the second steel cage 104 arranges two circles of the second vertical main reinforcement 104a, and the second vertical main reinforcement 104a diameters are not equal, d ₂ can take the maximum value, _Δ s can be the second vertical The adjustment amount of the spacing of the main reinforcement 104a, the value range of _△ s satisfies: 5≤ _△ s ≤ 120-d ₂ , and the unit of each parameter in the formula is millimeter.

1 and 2, in some embodiments, the value range of the height _H1 of the pile top 100a can be:

In the formula, γ _w can be the weight of water, γ _c can be the weight of concrete, H ₄ can be the height of the bottom surface of the pile top 100a from the high construction water level, A _c can be the bottom area of the cap 200, and B can be the pile The width of the cross-section of the top 100a, r ₁ can be the radius of the arc chamfer of the cross-section of the pile top 100a, n can be the number of bored piles 100, [τ] can be the allowable bonding strength of the concrete and steel surface , W can be the weight of the cap platform 200 construction cofferdam.

Referring to Fig. 14 and Fig. 15, in some embodiments, the bored pile 100 may also include a first steel casing 101a sleeved outside the first reinforcement cage 103, and the cross section of the bored pile 100 may be The center point of the cross-section is the origin O to establish a plane Cartesian coordinate system, wherein the X-axis can be parallel to the horizontal direction of the foundation, and the Y-axis can be parallel to the longitudinal direction of the foundation. The cross-section of the bored pile 100 can be divided into four quadrants. A vertical main reinforcement 103a is respectively arranged with the X axis and Y axis as symmetrical axes, and the first vertical main reinforcement 103a in the pile top 100a of each bored pile 100 within the entire cap range is arranged parallel to each other. A part of the first vertical main reinforcement 103a in 100a can be arranged at equal intervals along the four-side straight line segments of the cross-section of the pile top 100a, and the spacing s can be:

s=[4(B-2r ₁ )+2π(r ₁ -(t ₁ +f _average ))]/n ₁ ,

In the formula, B can be the width of the cross section of the pile top 100a, _r can be the radius of the circular chamfer of the pile top 100a, π can be the circumference ratio, _t can be the wall thickness of the first steel casing 101a, f _can be the average distance between the circumferential centerline of the planar layout of the first vertical main reinforcement 103a and the inner surface of the first steel casing 101a, when only one circle of the first vertical main reinforcement 103a is arranged, f ₌ f ₁ , when the arrangement When two circles of the first vertical main reinforcement 103a _{are equal} , f=(f ₁ +f ₂ )/2, and f ₁ and f ₂ represent the circumferential centerlines of the plane layout of the first and second circles of the first vertical main reinforcement 103a respectively The distance from the inner surface of the first steel casing 101a, n ₁ may be the number of the first vertical main ribs 103a in a single circle, where n ₁ may be equal to n ₂ ;

Another part of the first vertical main reinforcement 103a can be arranged along the circular arc chamfering section of the cross-section of the pile top 100a at equal deflection angles, and the size of the deflection angle α can be:

α=s/(r ₁ -(t ₁ +f _mean )),

In the formula, s can be the distance between the first vertical main reinforcement 103a arranged along the four-sided straight section of the cross-section of the pile top 100a, _r1 can be the radius of the circular chamfer of the pile top 100a, and _t1 can be the first steel guard The wall thickness of the cylinder 101a, f _can be the average distance between the circumferential centerline of the planar layout of the first vertical main reinforcement 103a and the inner surface of the first steel casing 101a, when only one circle of the first vertical main reinforcement 103a is arranged, f _Both = f ₁ , when two circles of first vertical main ribs 103a are arranged, f _equals = (f ₁ + f ₂ )/2, f ₁ and f ₂ respectively represent the first and second circles of first vertical main ribs 103a The distance between the circumferential centerline of the planar arrangement and the inner surface of the first steel casing 101a.

Referring to Fig. 14 and Fig. 15, in some embodiments, the bored pile 100 may also include a first steel casing 101a sleeved outside the first reinforcement cage 103, when two turns of the first reinforcement cage 103 are arranged inside the first reinforcement cage 103 In the case of a vertical main reinforcement 103a, the value range of the radius _r1 of the arc chamfer of the pile top 100a cross section can be:

((340+4d ₁ )/π+t ₁ +f ₂ )≤r ₁ ≤(1400/π+t ₁ +f ₁ ),

In the formula, d ₁ can be the diameter of the first vertical main rib 103a, when the diameters of the first vertical main rib 103a of the two circles are not equal, d ₁ can take the maximum value, π can be the circumference ratio, and t ₁ can be the first The wall thickness of the steel casing 101a, f ₁ and f ₂ can represent the distance between the circumferential centerline of the planar layout of the first vertical main reinforcement 103a of the first circle and the second circle and the inner surface of the first steel casing 101a, the formula The unit of each parameter is millimeter.

Referring to Fig. 1 and Fig. 7, in some embodiments, the ratio of the thickness H ₃ of the cap 200 to the diameter D of the pile body 100c can be: H ₃ /D≥1.2, so as to ensure the stress safety of the cap 200 and reduce the The amount of horizontal reinforcement at the bottom of the small platform 200.

Referring to Fig. 1, in some embodiments, the thickness of the bottom concrete 300 can be equal to the height of the pile top 100a, and since the cross section of the pile top 100a can be a square section with rounded corners, the construction of the cap 200 can be carried out by lowering the steel crane. In the box cofferdam, the inner support of the hanging box cofferdam and the surface of the pile top 100a are plane supports, which are more stable than the curved surface support of the circular pile top, more reliable in force transmission, better in integrity, and more convenient in construction. Concrete 300 is less affected by wave and current disturbance during pouring, and the quality of the back cover is better.

The principle of a deep water pile group foundation provided by the embodiment of the present invention is as follows:

Because a deep water pile group foundation can include: a plurality of bored piles 100, the bored piles 100 can have a pile top 100a, the cross section of the pile top 100a can be a square with circular arc chamfering, and the four straight sides of the square are respectively connected to The vertical and horizontal directions of the entire deep-water pile group foundation are parallel, and the inside of the bored pile 100 can be pre-embedded with a first reinforcement cage 103, and the cross-sectional shape of the first reinforcement cage 103 can be the same as the cross-sectional shape of the pile top 100a. The reinforcement cage 103 can include a plurality of first vertical main reinforcements 103a, and the first vertical main reinforcements 103a can be evenly spaced, that is, a part of the first vertical main reinforcements 103a can be respectively along the four sides of the cross-section of the pile top 100a. Set at equal intervals, the other part of the first vertical main reinforcement 103a can be set along the four circular arc chamfering sections of the cross section of the pile top 100a at equal deflection angles; the cap 200, the cap 200 can be fixed on the pile top 100a Above, the upper end of the first vertical main reinforcement 103a can be vertically inserted into the platform 200, and the bottom of the platform 200 can be provided with a plurality of horizontal steel bars 105, and the horizontal steel bars 105 can respectively pass from between two adjacent first vertical main reinforcements 103a. The gap passes through; the back cover concrete 300, the back cover concrete 300 is located within the height range of the pile top 100a below the cap 200, when the first vertical main reinforcement 103a is located within the range of the four-sided straight line section of the cross section of the first reinforcement cage 103, the second The planar arrangement of a vertical main bar 103a is parallel to the longitudinal and transverse directions of the entire foundation, and because the arrangement of the horizontal steel bars 105 at the bottom of the platform cap 200 is also parallel to the longitudinal and transverse directions of the entire foundation, only two adjacent first The net distance between the vertical main reinforcements 103a is set to be greater than the diameter of the horizontal reinforcement bars 105 at the bottom of the platform 200, so that the horizontal reinforcement bars 105 can smoothly pass from the two adjacent first reinforcement cages 103 within the range of the straight line section of the first reinforcement cage 103. The gaps between the vertical main reinforcements 103a pass through, and on average, there are 2 or 4 first vertical main reinforcements 103a in each bored pile 100 within the range of the circular arc chamfering section of the cross section of the first reinforcement cage 103, and the horizontal reinforcement cages 103 105 can also smoothly pass through the gap between two adjacent first vertical main ribs 103a within the range of the circular arc chamfering section of the cross section of the first reinforcement cage 103 through local bending. Therefore, the cap 200 The horizontal steel bar 105 at the bottom can pass through the width range of the first steel bar cage 103 smoothly, and there is no blind area within the width range of the first steel bar cage 103 where the horizontal steel bar 105 cannot pass through. All the horizontal steel bars 105 at the bottom of the platform cap 200 need not be cut off, they are kept in full length, and the spacing between the steel bars is even and uniform, and the density is appropriate. The construction difficulty of the horizontal steel bar 105 at the bottom of the cap 200 is reduced, the quality of concrete pouring of the cap 200 is guaranteed, the force is better, and the construction period of the cap 200 is shortened.

Since the cross section of the pile top 100a can be a square section with rounded corners, and the four sides of the square section can be parallel to the longitudinal and transverse directions of the foundation. For the foundation, the longitudinal and transverse directions are often the most unfavorable directions for the structural stress. When the square section is arranged parallel to the longitudinal and transverse directions of the foundation, the direction of the axis corresponding to the maximum moment of bending resistance of the section is the same as the direction of the bending moment, so the bearing is the same. When the bending moment acts, the section stress is the smallest, which is the most reasonable from a mechanical point of view.

Since the width B of the cross section of the pile top 100a can be equal to the diameter D of the cross section of the pile body 100c, that is, the cross section of the pile top 100a is a circumscribed square of the cross section of the pile body 100c, and the circumference of the cross section of the pile top 100a The length is 1.2 times of the circumference of the cross section of the pile body 100c. When the pile cap 200 performs the punching shear calculation, the equivalent punching shear area of the calculated punching cone produced by the pile top 100a is larger than that of the circular pile top. Therefore, under the condition of bearing the same load, the square pile top can effectively reduce the required thickness of the cap, which is about 0.8 times of the required thickness of the circular pile top, which reduces the engineering amount of the foundation.

Because the back-sealing concrete 300 is located within the height range of the pile top 100a below the cap 200, the cross section of the pile top 100a is a square section with circular arc chamfering, and the perimeter of the pile top 100a cross section is larger than the perimeter of the pile body 100c circular section. grow up, about 1.2 times the perimeter of the cross-section of the pile body 100c, because the bonded area of the pile top 100a and the bottom-sealing concrete 300 per unit height is proportional to the perimeter of the pile top 100a section, so it provides the same anti-floating bonding force In this case, the required thickness of the back-sealing concrete 300 is relatively small, about 0.8 times the required thickness of the circular pile top with the same width, which reduces the amount of foundation work.

Since the cross section of the pile top 100a can be a square section with circular arc chamfers, and the square section of the pile top 100a can be a circumscribed square of the circular section of the pile body 100c, it can effectively reduce the cap of the pile group foundation 200 and the thickness of the back cover concrete 300, which can reduce the self-weight of the foundation. For the friction pile foundation, the pile length required for the foundation can be shortened, and the project cost can be reduced.

Since the cross-section of the pile top 100a can be a square section with circular arc chamfers, when the steel hanging box cofferdam is lowered during the construction of the cap 200, the inner support of the hanging box cofferdam and the surface of the pile top 100a are planar supports, compared with the circular The surface support of the pile top is more stable, the force transmission is more reliable, the integrity is better, and the construction is more convenient. When the back cover concrete 300 is poured, it is less affected by wave and current disturbance, and the quality of the back cover is better.

In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description. It is not intended to indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and operate in a particular orientation, and thus should not be construed as limiting the invention. Unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be interpreted in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, It can also be an electrical connection; it can be a direct connection, or an indirect connection through an intermediary, or an internal communication between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

It should be noted that in the present invention, relative terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply There is no such actual relationship or order between these entities or operations. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above descriptions are only specific embodiments of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Accordingly, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

A deep water pile group foundation is characterized in that it comprises:

A plurality of bored piles (100), the bored piles (100) have a pile top (100a), the cross-sectional shape of the pile top (100a) is a square with circular arc chamfering, and the four straight sides of the square Respectively parallel to the longitudinal and transverse directions of the entire deep-water pile group foundation, a first reinforcement cage (103) is pre-embedded inside the pile top (100a), and the cross-sectional shape of the first reinforcement cage (103) is similar to that of the pile top (100a) have the same cross-sectional shape, and the first reinforcement cage (103) includes a plurality of first vertical main bars (103a) arranged at uniform intervals;

Cap (200), the cap (200) is fixed above the bored pile (100), a plurality of horizontal steel bars (105) are arranged in the bottom of the cap (200), and the first vertical The upper end of the main reinforcement (103a) is vertically inserted into the cap (200), and the horizontal reinforcement (105) within the width range of the first reinforcement cage (103) is separated from two adjacent first vertical reinforcement cages (103) respectively. The gap between the main ribs (103a) passes through;

The bottom sealing concrete (300), the bottom sealing concrete (300) is located within the height range of the pile top (100a) below the cap (200).
The deep water pile group foundation according to claim 1, characterized in that, the bored pile (100) further comprises:

Pile body (100c), the pile body (100c) is located below the pile top (100a), the cross-sectional shape of the pile body (100c) is circular, and the inside of the pile body (100c) is provided with a second reinforcement cage (104), the cross-sectional shape of the second reinforcement cage (104) is the same as the cross-sectional shape of the pile body (100c), and the second reinforcement cage (104) includes a plurality of first Two vertical main ribs (104a);

a transition section (100b), the transition section (100b) connects the pile top (100a) and the pile body (100c), the cross-sectional shape of the transition section (100b) is a square with rounded corners, And the radius of the arc chamfering of the cross section of the transition section (100b) is gradually along the height direction of the transition section (100b) from the top of the transition section (100b) to the bottom of the transition section (100b) become larger, the transition section (100b) has a plurality of third main ribs (103b) embedded inside, and the third main ribs (103b) connect the first vertical main ribs (103a) and the second vertical main ribs (104a) One-to-one correspondence linear connection.
Deep water pile group foundation as claimed in claim 2, is characterized in that:

The cross section of the pile top (100a) is a square with arc chamfers, and the width of the square cross section of the pile top (100a) is equal to the diameter of the circular cross section of the pile body (100c).
Deep water pile group foundation as claimed in claim 2, is characterized in that:

The height H2 of the transition section (100b) is greater than or equal to the diameter D of the pile body (100c).
The deep water pile group foundation according to claim 2, characterized in that, the radius r z of the arc chamfer of the cross section at any height of the transition section (100b) is:

r z =r 1 +(D/2-r 1 )×z/H 2 ,

In the formula, z is the height of any cross-section in the transition section (100b) from the bottom surface of the pile top (100a), H2 is the height of the transition section (100b), and D is the pile body ( 100c), r 1 is the radius of the arc chamfering of the pile top (100a) cross-section.
The deep water pile group foundation according to claim 2, characterized in that, the bored pile (100) further comprises a second steel casing (101c) sleeved outside the second reinforcement cage (104), so that The root number n of the second vertical main rib (104a) is:

n 2 ＝4 * Int([π * (D-2 * (t 2 +δ average ))]/[4 * (80+d 2 + △ s)]),

In the formula, π is the circumference ratio, D is the diameter of the pile body (100c), t is the wall thickness of the second steel casing (101c), and δ is the value of the second vertical main reinforcement (104a). The average distance between the circumferential centerline of the planar arrangement and the inner surface of the second steel casing (101c), d2 is the diameter of the second vertical main reinforcement (104a), and Δs is the second vertical main reinforcement (104a) The distance adjustment amount, the value of △ s satisfies: 5≤ △ s≤120-d 2 , and the unit of each parameter in the formula is millimeter.
Deep water pile group foundation as claimed in claim 1, is characterized in that, the value range of the height H of described pile top (100a) is:

H 1 ＞γ w H 4 [A c +0.86nr 1 ^2 -nB ^2 ]/[4n(B-0.43r 1 )[τ]+γ c (A c +0.86nr 1 ^2 -nB ^2 )+W],

In the formula, γ w is the weight of water, γ c is the weight of concrete, H 4 is the height of the bottom surface of the pile top (100a) from the construction high water level, A c is the bottom area of the cap (200), B is the width of the cross section of the pile top (100a), r is the radius of the arc chamfer of the pile top (100a) cross section, n is the root number of the bored pile (100), [ τ] is the allowable bonding strength of the concrete and the steel surface, and W is the weight of the construction cofferdam of the cap (200).
The deep water pile group foundation according to claim 1, characterized in that, the bored pile (100) further comprises a first steel casing (101a) sleeved outside the first reinforcement cage (103), partly The first vertical main reinforcement (103a) is arranged at equal intervals along the four-side straight sections of the cross-section of the pile top (100a), wherein the spacing s is:

s=[4(B-2r 1 )+2π(r 1 -(t 1 +f average ))]/n 1 ,

In the formula, B is the width of the cross-section of the pile top (100a), r1 is the radius of the arc chamfer of the cross-section of the pile top (100a), π is the circumference ratio, and t1 is the first steel The wall thickness of the casing (101a), f is the average distance between the circumferential centerline of the planar layout of the first vertical main reinforcement (103a) and the inner surface of the first steel casing (101a), and n1 is The root number of the first vertical main rib (103a) in a single circle;

Part of the first vertical main reinforcement (103a) along the cross-section of the pile top (100a) is arranged with equal deflection angles, wherein the size of the deflection angle α is:

α=s/(r 1 -(t 1 +f mean )),

In the formula, s is the distance between the first vertical main reinforcement (103a) arranged along the four-sided straight section of the cross-section of the pile top (100a), and r1 is the reverse arc of the cross-section of the pile top (100a). The radius of the corner, t1 is the wall thickness of the first steel casing (101a), and f is the circumferential centerline of the planar arrangement of the first vertical main reinforcement (103a) and the first steel casing (101a) Average distance of the inner surface.
The deep water pile group foundation according to claim 1, characterized in that, the bored pile (100) further comprises a first steel casing (101a) sleeved outside the first reinforcement cage (103), when When 2 circles of the first vertical main reinforcement (103a) are arranged in the first reinforcement cage (103), the value range of the radius r1 of the arc chamfer of the cross section of the pile top (100a) is:

((340+4d 1 )/π+t 1 +f 2 )≤r 1 ≤(1400/π+t 1 +f 1 ),

In the formula, d 1 is the diameter of the first vertical main reinforcement (103a), π is the circumference ratio, t 1 is the wall thickness of the first steel casing (101a), f 1 and f 2 respectively represent the first circle , the distance between the circumferential centerline of the planar layout of the first vertical main reinforcement (103a) of the 2nd circle and the inner surface of the first steel casing (101a), the unit of each parameter in the formula all adopts millimeter.
The pile group foundation in deep water as claimed in claim 2, characterized in that, the value range of the ratio of the thickness H3 of the cap (200) to the diameter D of the pile body (100c) is:

H 3 /D≥1.2.