Shared large-diameter batter pile foundation abutment structure and construction method thereof

Abstract

A shared large-diameter inclined pile foundation arch abutment structure and its construction method are disclosed to significantly reduce the amount of excavation and masonry work required for the arch abutment foundation, minimize environmental damage, and meet the requirements of structural safety, durability, and engineering economy. The structure includes pile foundations, junction piers, and truss arch bridge chords. The pile foundations consist of two lower large-diameter piles and two upper large-diameter piles spaced apart in the transverse direction of the bridge. Each lower and upper large-diameter pile is inclined and embedded in the foundation rock, forming inclination angles α and β with the resultant force direction of the arch foot in the longitudinal and transverse directions, respectively. The tops of the lower and upper large-diameter piles on the same side in the transverse direction are fixed to the frame beam, forming a portal frame structure. The junction piers are fixed to the upper top surface of the frame beam on the same side, with their axis perpendicular to the upper top surface. The truss arch bridge chords include upper and lower chords, which are fixedly connected to the upper inclined surface of the frame beam on the same side, with their tangents perpendicular to the upper inclined surface.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, specifically to a shared large-diameter inclined pile foundation arch structure and its construction method. Background Technology

[0002] With the rapid development of highway bridge construction in my country, the design process has increasingly encountered projects requiring long-span arch bridges to cross high mountains and deep valleys. Arch bridges are highly adaptable to mountainous environments, aesthetically pleasing, and have strong spanning capabilities, making them particularly suitable for V-shaped deep valley terrain. Furthermore, arch bridges offer good durability, low maintenance costs, and low construction costs. Due to these characteristics, arch bridges have seen rapid development in my country's highway bridge construction. Examples include the Xiangxi Yangtze River Highway Bridge with a main span of 519m (calculated span), the Tian'e Longtan Grand Bridge with a main span of 600m (calculated span), the Pingnan Third Bridge with a main span of 575m (calculated span), and the Hejiang Yangtze River Bridge with a main span of 530m (calculated span), among other long-span arch bridges.

[0003] For long-span arch bridges, the arch bridge itself has a large self-weight, and its load is transferred to the foundation through the arch abutment foundation. Therefore, this type of bridge has high requirements for the bearing capacity of the foundation. However, poor geological conditions with weak foundation bearing capacity greatly limit the construction of arch bridges, which is a great challenge for designers.

[0004] Taking the construction of a steel truss arch bridge with a main span of 580m (calculated span) under geological conditions of moderately weathered mudstone with a foundation bearing capacity of 500KPa as an example, if the traditional enlarged foundation scheme is adopted, it is necessary to increase the contact area between the arch abutment and the soil. The size of the arch abutment is relatively large, and the amount of concrete required is at least 60,000 m³. 3 Furthermore, the excavation volume for the arch abutment is very large, resulting in a significant environmental impact. If a composite pile foundation scheme is adopted, the pile foundation is subject to complex stresses, the load-sharing ratio is unclear, and vertical and inclined piles cannot be constructed simultaneously, leading to a long construction period.

[0005] Therefore, in view of the shortcomings of the existing technology, a shared large-diameter inclined pile foundation arch structure and its construction method have been invented, which is particularly suitable for building truss arch bridges on poor geological conditions with weak foundation bearing capacity. Summary of the Invention

[0006] The technical problem this institute aims to solve is to provide a shared large-diameter inclined pile foundation arch abutment structure to significantly reduce the amount of excavation and masonry work required for the arch abutment foundation, minimize environmental damage, and meet the requirements of structural safety, durability, and engineering economy.

[0007] The technical solution adopted by this invention to solve its technical problem is as follows:

[0008] This invention discloses a shared large-diameter inclined pile foundation arch abutment structure, comprising a pile foundation, a junction pier, and a truss arch bridge chord. The pile foundation consists of two lower large-diameter piles and two upper large-diameter piles spaced apart in the transverse direction of the bridge. Each lower and upper large-diameter pile is inclined and embedded into the foundation rock, forming inclination angles α and β with the resultant force direction of the arch foot in the longitudinal and transverse directions, respectively. The tops of the lower and upper large-diameter piles on the same side in the transverse direction are integrally fixed to the frame beam, forming a portal frame structure. The junction pier is fixed to the upper top surface of the frame beam on the same side, with its axis perpendicular to the upper top surface. The truss arch bridge chord includes an upper chord and a lower chord, which are fixedly connected to the upper inclined surface of the frame beam on the same side, with their tangents perpendicular to the upper inclined surface.

[0009] The tilt angle α is calculated using the following formula:

[0010] Inclination angle α = α1 - α2

[0011] sinα2=(N*sinα1+G) / (N*cosα1)

[0012] In the formula, α1 is the angle between the axial force at the top of the arch abutment and the horizontal direction, α2 is the angle between the axial force of the arch abutment foundation and the horizontal direction, N is the axial force transmitted to the arch abutment foundation by the chords and junction piers of the truss arch bridge, and G is the self-weight of the frame beam.

[0013] The inclination angle β is the angle between the axial force at the top of the arch seat and the vertical direction, and is determined by calculation based on the bridge structure.

[0014] Another technical problem to be solved by the present invention is to provide a shared large-diameter inclined pile foundation arch abutment structure, comprising the following steps:

[0015] S1: Clean the foundation surface, excavate the large-diameter inclined pile opening on the upper side, set up a drainage system at the top and bottom of the slope, and take precautions against falling rocks.

[0016] S2: Construct the upper pile sleeve arch and pipe shed, and fix the guide pipe on the steel frame inside the upper pile sleeve arch;

[0017] S3: Excavate the upper large-diameter pile hole using the drill and blast method, excavate along the pile axis with equal cross sections, and insert small guide pipes or anchors into the surrounding rock along the pile radial direction during construction to initially support the foundation around the pile diameter.

[0018] S4: Pour concrete into the upper large-diameter pile body;

[0019] S5: Remove the upper pile arch and support, excavate the lower large-diameter pile hole, set up a side intercepting drainage system at the top and bottom of the slope, and take precautions against falling rocks.

[0020] S6: Construct the lower pile sleeve arch and pipe shed, and fix the guide pipe on the steel frame inside the lower pile sleeve arch;

[0021] S7: The large-diameter pile hole is excavated by drilling and blasting. The excavation is carried out along the pile axis with equal cross sections. During the construction process, small guide pipes or anchors are inserted into the surrounding rock along the pile radial direction to initially support the foundation around the pile diameter.

[0022] S8: Pour concrete into the lower large-diameter pile body;

[0023] S9: Remove the lower pile arch and support;

[0024] S10: Pouring concrete for the frame beams;

[0025] S11: Construct the junction pier on the top surface of the upper end of the frame beam, and construct the truss arch bridge chord on the upper inclined surface of the frame beam.

[0026] The beneficial effects of this invention are mainly reflected in the following aspects:

[0027] 1. Large-diameter pile foundations are embedded obliquely into poor geological conditions with weak bearing capacity. By adjusting the inclination angle of each large-diameter pile and setting eccentricity, the pile axis is compressed, and the upper load is transferred to the large-diameter pile foundation through the frame beam, and finally transferred to the depth of the foundation. The load transfer path is clear, and the foundation stress is simple and reasonable.

[0028] Second, under the same geological conditions, compared with composite pile foundations and traditional spread foundations, the truss arch frame type large-diameter inclined pile foundation structure has a shorter construction cycle, smaller foundation excavation volume, smaller masonry volume, less environmental damage, lower construction and support costs, and better economic efficiency.

[0029] Third, the junction pier and the truss arch bridge chord share a large-diameter inclined pile foundation arch seat, which can significantly reduce the amount of excavation and masonry work for the arch seat foundation, minimize environmental damage, and meet the requirements of structural safety, durability, and engineering economy.

[0030] IV. It is particularly suitable for constructing truss arch bridges on poor geological conditions with weak foundation bearing capacity. Attached Figure Description

[0031] This instruction manual includes the following nine figures:

[0032] Figure 1 This is an elevation view of a shared large-diameter inclined pile foundation arch structure according to the present invention;

[0033] Figure 2 This is a plan view of the large-diameter inclined pile in the shared large-diameter inclined pile foundation arch structure of the present invention;

[0034] Figure 3 This is a top view of a shared large-diameter inclined pile foundation arch structure according to the present invention;

[0035] Figure 4 It is along Figure 1 Cross-sectional view of line AA in the middle;

[0036] Figure 5 It is along Figure 1 Cross-sectional view of the middle BB line;

[0037] Figures 6 to 9 This invention provides a schematic diagram of the construction process of a shared large-diameter inclined pile foundation arch structure.

[0038] The diagram shows the components and their corresponding markings: lower large-diameter pile 11, upper large-diameter pile 12, pile bottom enlarged head 13, frame beam 20, upper top surface C, upper inclined surface D, junction pier 30, upper chord 41, lower chord 42, slope reinforcement structure 50, upper pile construction platform 61, lower pile construction platform 62, upper intercepting drainage system 71, lower intercepting drainage system 72, upper pile sleeve arch 81, lower pile sleeve arch 82, pipe shed 90, small guide pipe or anchor 91. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] Reference Figures 1 to 5 This invention discloses a shared large-diameter inclined pile foundation arch abutment structure, comprising a pile foundation, a junction pier 30, and truss arch bridge chords. The pile foundation consists of two lower large-diameter piles 11 and two upper large-diameter piles 12 spaced apart in the transverse direction of the bridge. Each lower large-diameter pile 11 and upper large-diameter pile 12 is inclined and embedded into the foundation rock, forming inclination angles α and β with the resultant force direction of the arch foot in the longitudinal and transverse directions of the bridge, respectively. The tops of the lower large-diameter piles 11 and upper large-diameter piles 12 on the same side of the transverse direction are integrally fixed to the frame beam 20, forming a portal frame structure. The junction pier 30 is fixed to the upper top surface C of the frame beam 20 on the same side, with its axis perpendicular to the upper top surface C. The truss arch bridge chords include an upper chord 41 and a lower chord 42, which are fixedly connected to the upper inclined surface D of the frame beam 20 on the same side, with their tangents perpendicular to the upper inclined surface D.

[0041] Reference Figure 1The shared large-diameter inclined pile foundation described herein is a reinforced concrete structure. The loads of the upper chord 41 and the junction pier 30 of the truss arch bridge are mainly transferred to the upper large-diameter pile 12 through the frame beam 20, and the loads of the lower chord 42 of the truss arch bridge are mainly transferred to the lower large-diameter pile 11 through the frame beam 20. Finally, the loads are transferred to the deep foundation through the upper large-diameter pile 12 and the lower large-diameter pile 11. The load transfer path is clear, and the foundation stress is simple and reasonable. Under the same geological conditions, compared with composite pile foundations and traditional spread foundations, the truss arch frame-type large-diameter inclined pile foundation structure has a shorter construction period, smaller foundation excavation volume, smaller masonry volume, less environmental damage, lower construction and support costs, and better economic efficiency. Taking the construction of an arch bridge with a main span of 580m (calculated span) under geological conditions of moderately weathered mudstone with a foundation bearing capacity of 500KPa as an example, the shared large-diameter inclined pile foundation structure of this invention can reduce the foundation masonry volume by approximately 50,000m³. 3 It has the obvious characteristics of small excavation volume, small masonry volume, clear structural load transfer path, small environmental damage and convenient construction of arch foundation, which is of positive and important significance for meeting the performance of structural safety, durability and engineering economy.

[0042] Based on the stress characteristics of arch bridges, the large-diameter inclined piles are embedded in the rock mass at an angle α and an angle β with the resultant force direction of the arch foot in the longitudinal and transverse directions of the bridge, respectively.

[0043] The tilt angle α is calculated using the following formula:

[0044] Inclination angle α = α1 - α2

[0045] sinα2=(N*sinα1+G) / (N*cosα1)

[0046] In the formula, α1 is the angle between the axial force at the top of the arch abutment and the horizontal direction, α2 is the angle between the axial force of the arch abutment foundation and the horizontal direction, N is the axial force transmitted to the arch abutment foundation by the chords and junction piers of the truss arch bridge, and G is the self-weight of the frame beam.

[0047] The inclination angle β is the angle between the axial force at the top of the arch abutment and the vertical direction, and is determined by calculation based on the bridge type. The inclination angle β is related to the form of the bridge structure. If it is a parallel arch, the inclination angle is 0 degrees; if it is a basket arch, the inclination angle β ≠ 0 degrees.

[0048] The lower large-diameter pile 11 and upper large-diameter pile 12 are preferably reinforced concrete piles. The loads on the upper chord 41 and lower chord 42 of the truss arch are directly transferred to the depth of the foundation through the pile foundation. (Refer to...) Figure 1 To increase the bearing capacity of the foundation, the lower ends of the lower large-diameter pile 11 and the upper large-diameter pile 12 are provided with pile bottom enlarged heads 13, the diameter of which is 1.5 to 2.5 times the pile diameter.

[0049] Reference Figures 6 to 9The present invention discloses a construction method for a shared large-diameter inclined pile foundation arch abutment structure, comprising the following steps:

[0050] S1: Clean the foundation surface, excavate the 12 holes for the large-diameter piles on the upper side, set up the drainage system 71 at the top and bottom of the slope, and take precautions against falling rocks.

[0051] S2: Construct the upper pile sleeve arch 81 and pipe shed 90, and fix the guide pipe on the steel frame inside the upper pile sleeve arch 81;

[0052] S3: Excavate the upper large-diameter pile 12 tunnel body by drilling and blasting method, excavate along the pile axis with equal cross section, and insert small guide pipes or anchors 91 into the surrounding rock body along the pile radial direction during construction to initially support the foundation around the pile diameter.

[0053] S4: Pour concrete into the body of the 12 large-diameter piles on the upper side;

[0054] S5: Remove the upper pile arch 81 and support, excavate the lower large-diameter pile 11 opening, set up a side intercepting drainage system 72 at the top and bottom of the slope, and take measures to prevent falling rocks.

[0055] S6: Construct the lower pile sleeve arch 82 and pipe roof 90, and fix the guide pipe on the steel frame inside the lower pile sleeve arch 82;

[0056] S7: Excavate the lower large-diameter pile 11 tunnel body using the drill and blast method, excavate along the pile axis with equal cross sections, and insert small guide pipes or anchors 91 into the surrounding rock mass along the pile radial direction during construction to initially support the foundation around the pile diameter.

[0057] S8: Pour concrete into the lower large-diameter pile 11;

[0058] S9: Remove the lower side pile arch 82 and its support;

[0059] S10: Pour 20 mm of concrete for the frame beam;

[0060] S11: Construct the junction pier 30 on the top surface C of the upper end of the frame beam 20, and construct the truss arch bridge chord on the inclined surface D of the upper end of the frame beam 20.

[0061] The above description is merely an illustration of some principles of the shared large-diameter inclined pile foundation arch structure and its construction method of the present invention. It is not intended to limit the present invention to the specific structures and applicable scope shown and described. Therefore, all possible modifications and equivalents are within the scope of the patent application of the present invention.

Claims

1. A shared large diameter batter pile foundation abutment construction comprising pile foundations, a joint pier (30) and a trussed arch bridge chord, characterised by: The pile foundation consists of two lower large-diameter piles (11) and two upper large-diameter piles (12) spaced apart in the transverse direction of the bridge. Each lower large-diameter pile (11) and upper large-diameter pile (12) is inclined and embedded into the foundation rock, forming an inclination angle α and an inclination angle β with the direction of the resultant force of the arch foot in the longitudinal direction of the bridge and the transverse direction of the bridge, respectively. The top of the lower large-diameter piles (11) and upper large-diameter piles (12) on the same side of the transverse direction of the bridge are fixed to the frame beam (20) to form a portal frame structure. The junction pier (30) is fixed on the top surface (C) of the upper end of the frame beam (20) on the same side, and its axis is perpendicular to the top surface (C). The chord of the truss arch bridge includes an upper chord (41) and a lower chord (42). The upper chord (41) and the lower chord (42) are fixedly connected to the upper inclined surface (D) of the frame beam (20) on the same side, and their tangents are perpendicular to the upper inclined surface (D). The tilt angle α is calculated using the following formula: Inclination angle α = α1 - α2 sinα2=(N*sinα1+G) / (N*cosα1) In the formula: α1 is the angle between the axial force at the top of the arch abutment and the horizontal direction, α2 is the angle between the axial force at the foundation of the arch abutment and the horizontal direction, N is the axial force transmitted to the foundation of the arch abutment by the chord of the truss arch bridge and the junction pier, and G is the self-weight of the frame beam. The inclination angle β is the angle between the axial force at the top of the arch and the vertical direction, and is determined by calculation based on the bridge structure.

2. The shared large-diameter inclined pile foundation arch abutment structure as described in claim 1, characterized in that: The lower ends of the large-diameter piles (11) and (12) on the lower side have enlarged heads (13) with a diameter of 1.5 to 2.5 times the pile diameter.

3. The shared large-diameter inclined pile foundation arch abutment structure as described in claim 1, characterized in that: The section below the intersection of the lower large-diameter pile (11), the upper large-diameter pile (12) and the frame beam (20) is filled with plain concrete.

4. A construction method for a shared large-diameter inclined pile foundation arch abutment structure as described in any one of claims 1 to 3, comprising the following steps: S1: Clean the foundation surface, excavate the upper large-diameter pile (12) opening, set up a drainage system (71) at the top and bottom of the slope, and take measures to prevent dangerous rocks from falling. S2: Construct the upper pile sleeve arch (81) and pipe shed (90), and fix the guide pipe on the steel frame inside the upper pile sleeve arch (81); S3: Excavate the upper large-diameter pile (12) tunnel body by drilling and blasting, excavate along the pile axis with equal cross sections, and insert small guide pipes or anchors (91) into the surrounding rock body along the pile radial direction during construction to initially support the foundation around the pile diameter. S4: Pour concrete into the upper large-diameter pile (12); S5: Remove the upper pile arch (81) and support, excavate the lower large-diameter pile (11) opening, set up a side intercepting drainage system (72) at the top and bottom of the slope, and take measures to prevent dangerous rocks from falling. S6: Construct the lower pile sleeve arch (82) and pipe shed (90), and fix the guide pipe on the steel frame inside the lower pile sleeve arch (82); S7: Excavate the lower side of the large diameter pile (11) tunnel body by drilling and blasting, excavate along the pile axis with equal cross sections, and insert small guide pipes or anchors (91) into the surrounding rock body along the pile radial direction during construction to initially support the foundation around the pile diameter. S8: Pour concrete into the lower large-diameter pile (11); S9: Remove the lower side pile arch (82) and support; S10: Pour concrete for the frame beam (20); S11: Construct the junction pier (30) on the top surface (C) of the upper end of the frame beam (20), and construct the truss arch bridge chord on the upper inclined surface (D) of the frame beam (20).

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