Bridge pile foundation structure

Abstract

The utility model discloses a bridge pile foundation structure which solves the technical problem of improving the stability of a pile foundation in a hard rock stratum (full granite stratum). Comprising a large-diameter hard rock pile foundation section which is arranged below a bearing platform and directly supports the bearing platform; the small-diameter hard rock pile foundation section is arranged at the lower end of the large-diameter hard rock pile foundation section, and a pile shoulder is formed between the small-diameter hard rock pile foundation section and the large-diameter hard rock pile foundation section; the oblique anchor rod system comprises a plurality of oblique anchor rods distributed on the periphery of the large-diameter hard rock pile foundation section and / or the small-diameter hard rock pile foundation section, the upper ends of the oblique anchor rods are connected with the large-diameter hard rock pile foundation section into a whole, and the lower ends of the oblique anchor rods extend outwards. The load transmission path of the pile foundation and the hard rock stratum is improved, the anchoring effect of the pile foundation and the hard rock stratum is enhanced, and therefore the stability and the bearing capacity of the bridge pile foundation structure are improved.

Description

Technical Field

[0001] The utility model relates to a bridge pile foundation structure, in particular to a bridge pile foundation structure applied in hard rock strata (such as full granite strata). Background Art

[0002] Construction of bridge pile foundations in granite strata requires drilling into intact granite strata. Due to granite's high hardness and compressive strength, drilling is difficult and slow. Controlling the verticality and wall stability of the drill hole is challenging, placing high demands on the drilling rig and drill bit. Furthermore, because granite strata exert little friction on the pile sides, increasing the roughness of the pile shaft (such as by strengthening the pile ribs or creating a concave-convex structure) is often necessary to enhance this friction, further increasing the difficulty and cost of constructing bridge pile foundations in granite strata. Utility Model Content

[0003] The purpose of the utility model is to provide a bridge pile foundation structure to solve the technical problem of improving the stability of the pile foundation in a hard rock formation (full granite formation).

[0004] The bridge pile foundation structure is arranged in a hard rock formation and includes: a large-diameter hard rock pile foundation section, which is arranged below the pedestal and directly supports the pedestal; a small-diameter hard rock pile foundation section, which is arranged at the lower end of the large-diameter hard rock pile foundation section and forms a pile shoulder between the large-diameter hard rock pile foundation section; and an inclined anchor rod system, which includes a plurality of inclined anchor rods distributed around the large-diameter hard rock pile foundation section and / or the small-diameter hard rock pile foundation section, wherein the upper ends of these inclined anchor rods are connected to the large-diameter hard rock pile foundation section as a whole and the lower ends extend outward.

[0005] As an improvement and / or instantiation of the above-mentioned bridge pile foundation structure, further: the oblique anchor rod is a cast-in anchor rod formed by pouring concrete into an oblique hole opened obliquely downward.

[0006] As an improvement and / or instantiation of the above-mentioned bridge pile foundation structure, further: steel bars are embedded in the cast-in-place anchor rods, and the upper ends of the steel bars are inserted into the large-diameter hard rock pile foundation sections.

[0007] As an improvement and / or instantiation of the above-mentioned bridge pile foundation structure, further: the inclined hole is formed by a rock-breaking drill hole opened in the foundation before the large-diameter hard rock pile foundation section is excavated.

[0008] As an improvement and / or instantiation of the above-mentioned bridge pile foundation structure, further: the diameter of the inclined hole is 100mm-200mm.

[0009] As an improvement and / or embodiment of the above-mentioned bridge pile foundation structure, further: the upper ends of the oblique anchor rods are connected to the pile shoulder.

[0010] As an improvement and / or embodiment of the above-mentioned bridge pile foundation structure, further: these oblique anchor rods are circumferentially spaced around the large-diameter hard rock pile foundation section and / or the small-diameter hard rock pile foundation section.

[0011] As an improvement and / or instantiation of the above-mentioned bridge pile foundation structure, further: the hard rock formation is a full granite formation.

[0012] The above-mentioned bridge pile foundation structure forms a pile shoulder by combining a large-diameter hard rock pile foundation section with a small-diameter hard rock pile foundation section, and an oblique anchor system is provided, which improves the load transfer path between the pile foundation and the hard rock formation, enhances the anchoring effect of the pile foundation and the hard rock formation, and thus improves the stability and bearing capacity of the bridge pile foundation structure.

[0013] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be learned through practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings that constitute part of this specification are used to assist in understanding the present invention. The contents provided in the drawings and the related descriptions in this specification can be used to explain the present invention, but do not constitute an improper limitation on the present invention.

[0015] Figure 1 This is a schematic diagram of a bridge pile foundation structure according to an embodiment of the present utility model.

[0016] Figure 2 for Figure 1 Schematic diagram of rock-breaking boreholes formed during the construction of the bridge pile foundation structure. DETAILED DESCRIPTION

[0017] The following is a clear and complete description of the present invention in conjunction with the accompanying drawings. A person skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be noted that:

[0018] The technical solutions and technical features provided in each section, including the following description, may be combined with each other unless they conflict. In addition, where possible, these technical solutions, technical features, and related combinations may be assigned specific technical themes and protected by relevant patents.

[0019] The embodiments of the utility model involved in the following description are generally only a part of the embodiments rather than all the embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making any creative work should fall within the scope of patent protection.

[0020] Regarding terms and units in this specification: The terms "include," "comprising," and any variations thereof in this specification, the corresponding claims, and related sections are intended to cover non-exclusive inclusions. Other relevant terms and units are to be reasonably interpreted based on the relevant content provided in this specification.

[0021] Figure 1 This is a schematic diagram of a bridge pile foundation structure according to an embodiment of the present utility model. Figure 2 for Figure 1 The diagram below shows the rock-breaking holes formed during the construction of the bridge pile foundation structure. Figure 1-Figure 2 As shown, the bridge pile foundation structure of an embodiment of the present invention is installed in a hard rock formation (specifically, a moderately or slightly weathered granite formation) and includes: a large-diameter hard rock pile foundation section 21, disposed below and directly supporting a cap 1; a small-diameter hard rock pile foundation section 22, disposed at the lower end of the large-diameter hard rock pile foundation section 21 and forming a pile shoulder 23 therebetween; and an inclined anchor system 24, comprising a plurality of inclined anchor rods 241 distributed around the perimeter of the small-diameter hard rock pile foundation section 22. The upper ends of these inclined anchor rods 241 are integrally connected to the large-diameter hard rock pile foundation section 21, and the lower ends extend outward. Specifically, the upper ends of these inclined anchor rods 241 are connected to the pile shoulder 23. Furthermore, these inclined anchor rod rings 241 are spaced apart around the perimeter of the large-diameter hard rock pile foundation section 21 and / or the small-diameter hard rock pile foundation section 22.

[0022] The construction method for the bridge pile foundation structure is as follows: First, before excavating the large-diameter hard rock pile foundation section 21, a rock-breaking drill hole 3 (with a diameter of 100mm-200mm) is drilled in the foundation. These drill holes 3 can be all or partly oblique. The purpose of the rock-breaking drill holes 3 is to destroy the hard rock strata and reduce drilling resistance during excavation of the large-diameter hard rock pile foundation section 21. Furthermore, the rock-breaking drill holes 3 provide a foundation for the subsequent installation of the oblique anchor system 24. Subsequently, excavation of the large-diameter hard rock pile foundation section 21 proceeds. The large-diameter hard rock pile foundation section 21 typically has a diameter of over 2 meters. The pre-excavation of the rock-breaking drill holes 3 significantly reduces the difficulty of excavating the large-diameter hard rock pile foundation section 21. After excavation of the large-diameter hard rock pile foundation section 21 is completed, the small-diameter hard rock pile foundation section 22 is excavated. The small-diameter hard rock pile foundation section 22 has a smaller diameter than the large-diameter hard rock pile foundation section 21, thereby forming a pile shoulder 23 between the small-diameter hard rock pile foundation section 21 and the large-diameter hard rock pile foundation section 21. The perimeter of the pile shoulder 23 forms the remaining portion of the rock-breaking drill hole 3, which is used to form the cast-in anchor bolt. After the small-diameter hard rock pile foundation section 22 is excavated, a steel cage is placed and rebar is implanted into the reserved channel at the pile shoulder 23 in the rock-breaking drill hole 3. Concrete is then poured to form the large-diameter hard rock pile foundation section, the small-diameter hard rock pile foundation section, and the cast-in anchor bolt. The cast-in anchor bolt is also known as the oblique anchor bolt.

[0023] The function of the aforementioned pile shoulder 23 is that the provision of the pile shoulder 23 improves the load transfer path. When the vertical load transmitted by the pile cap 1 is transmitted downward through the large-diameter hard rock pile foundation section 21, part of the load is directly transferred to the rock formation at the pile shoulder 23, while the remaining load continues to be transmitted downward through the small-diameter hard rock pile foundation section 22, thereby reducing the vertical load of the small-diameter hard rock pile foundation section 22. Since the small-diameter hard rock pile foundation section 22 is easier to excavate than the large-diameter hard rock pile foundation section 21, the overall construction difficulty of the bridge pile foundation structure is reduced. At the same time, the horizontal load is further transmitted at the pile shoulder 23 due to the additional constraint of the rock formation (when the upper end of the oblique anchor 241 is connected to the pile shoulder 23, it can also be transmitted through the synergistic effect of the oblique anchor system), thereby forming a multi-stage dispersed force transmission mechanism, avoiding stress concentration, and improving force transmission uniformity.

[0024] It can be seen that the bridge pile foundation structure of this embodiment not only improves the load transfer path between the pile foundation and the hard rock formation, enhances the anchoring effect between the pile foundation and the hard rock formation, thereby improving the stability and bearing capacity of the bridge pile foundation structure, but also reduces the construction difficulty of the bridge pile foundation structure through the rock-breaking drilling hole 3 and the small-diameter hard rock pile foundation section 22.

[0025] The above describes the relevant contents of the present invention. Based on these descriptions, a person skilled in the art will be able to implement the present invention. Based on the above contents of this specification, all other embodiments obtained by a person skilled in the art without inventive work should fall within the scope of patent protection.

Claims

1. The bridge pile foundation structure is set in hard rock formations and is characterized by: include: A large diameter hard rock pile foundation section is set below the cap and directly supports the cap; a small-diameter hard rock pile foundation section, disposed at the lower end of the large-diameter hard rock pile foundation section and forming a pile shoulder between the large-diameter hard rock pile foundation section; The inclined anchor rod system includes several inclined anchor rods distributed around the large diameter hard rock pile foundation section and / or the small diameter hard rock pile foundation section. The upper ends of these inclined anchor rods are connected to the large diameter hard rock pile foundation section as a whole and the lower ends extend outward.

2. The bridge pile foundation structure according to claim 1, characterized in that: The oblique anchor rod is a cast-in anchor rod formed by pouring concrete into an oblique hole opened obliquely downward.

3. The bridge pile foundation structure according to claim 2, characterized in that: A steel bar is embedded in the cast-in-place anchor rod, and the upper end of the steel bar is inserted into the large-diameter hard rock pile foundation section.

4. The bridge pile foundation structure according to claim 2, wherein: The inclined hole is formed by a rock-breaking drill hole opened on the foundation before the large-diameter hard rock pile foundation section is excavated.

5. The bridge pile foundation structure according to claim 2, characterized in that: The diameter of the oblique hole is 100mm-200mm.

6. The bridge pile foundation structure according to claim 1, characterized in that: The upper ends of these oblique anchor rods are connected to the pile shoulder.

7. The bridge pile foundation structure according to claim 1, characterized in that: These oblique anchor rods are circumferentially spaced around the large-diameter hard rock pile foundation section and / or the small-diameter hard rock pile foundation section.

8. The bridge pile foundation structure according to claim 1, characterized in that: The hard rock formation is a pure granite formation.

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