Triangular pile supporting structure and construction method

Abstract

The invention relates to a triangular pile supporting structure and a construction method, the pile supporting structure comprises a pile supporting unit, the pile supporting unit comprises a plurality of fender posts, and the fender posts are arranged in rows along the inner side wall of a foundation pit; the combined piles are arranged in the foundation pit and right face the row of fender posts, and the combined piles comprise three supporting piles; every two adjacent fender posts are connected through the corresponding supporting beams, the combined piles are connected with the fender posts through the supporting beams, the three supporting piles are sequentially connected through the supporting beams to form a triangle, and the three supporting piles are located at the three vertexes of the triangle respectively. Through the arrangement, the damage of internal stress to the pile support structure is reduced, and the deformation resistance and stability of the whole structure are enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit support, and in particular to a triangular pile support structure and a construction method. Background Art

[0002] With the rapid advancement of urbanization and the increasing shortage of land resources, the development and utilization of underground space has gradually become one of the important means of urban construction. More and more large-scale building complex projects adopt the design of merging basements in planning, which makes the underground structure integrated and forms a foundation pit project with a very large area. However, the rise of such projects has also brought unprecedented severe challenges to foundation pit support technology.

[0003] The size of super-large foundation pits is large. If the traditional bracing support system is applied to super-large foundation pits, the support length is often too long and is easily affected by temperature stress. When the ambient temperature changes, the overly long support structure will produce internal stress due to thermal expansion and contraction, resulting in damage to the support structure itself, which seriously weakens the support effect on the side walls of the foundation pit and threatens the stability and safety of the entire foundation pit project. Moreover, super-large foundation pits are often located in densely populated urban centers, and there are a large number of existing underground structures in the surrounding environment of the foundation pits, such as subway tunnels and urban underground pipe galleries. Traditional support technologies such as the setting of the support system may conflict with the spatial position of the existing underground structure, or the anchor construction in the pile-anchor support technology may damage the existing underground structure, thereby causing safety hazards. Summary of the invention

[0004] In order to solve the above-mentioned defects, the present invention proposes a triangular pile support structure and a construction method.

[0005] The technical solution adopted by the present invention is a triangular pile support structure, including a pile support unit, wherein the pile support unit includes:

[0006] A plurality of retaining piles, wherein the plurality of retaining piles are arranged in a row along the inner wall of the foundation pit;

[0007] A composite pile, which is arranged inside the foundation pit and directly faces a row of the retaining piles, and the composite pile includes three retaining piles;

[0008] A plurality of support beams, two adjacent retaining piles are connected by the support beams, the combined piles are connected to the retaining piles by the support beams, three retaining piles are connected in sequence by the support beams to form a triangle, and the three retaining piles are respectively located at the three vertices of the triangle.

[0009] Preferably, along the arrangement direction of a row of the retaining piles, the length of the triangle is smaller than the length of a row of the retaining piles.

[0010] Preferably, the three supporting piles of the combined pile form an isosceles triangle, and the bases of the isosceles triangle are parallel and close to the surrounding piles arranged in a row.

[0011] Preferably, the vertex angle of the isosceles triangle is 60 degrees to 90 degrees.

[0012] Preferably, along a direction perpendicular to a row of the retaining piles, two of the retaining piles on the bottom edge are connected to the retaining piles via the support beam.

[0013] Preferably, the pile-supporting unit further comprises a reinforcement beam located inside the triangle, and two ends of the reinforcement beam are respectively connected to the supporting piles and the support beam.

[0014] Preferably, it comprises a plurality of pile-supporting units, and a plurality of rows of retaining piles of the plurality of pile-supporting units are connected end to end through the supporting beams and are evenly laid on the inner wall of the foundation pit.

[0015] Preferably, two adjacent supporting piles on two adjacent bottom edges are connected by the supporting beam.

[0016] The present invention also proposes a construction method of the above-mentioned triangular pile support structure, the method comprising:

[0017] S1. Analyze the geological survey report, find out the geological conditions, determine the pile diameter, pile spacing, embedding depth of the retaining piles and supporting piles and the size of the support beam according to the bottom elevation requirements of the foundation pit, and determine the spacing between adjacent combined piles;

[0018] S2. Use a rotary drilling rig or an impact drilling rig to drill holes in the retaining piles and the supporting piles, and construct the retaining piles and the supporting piles;

[0019] S3, the bottom elevation of the supporting beam from the first layer of earth excavation to the top;

[0020] S4, constructing the support beam at the top;

[0021] S5, excavating to the bottom elevation of the first supporting beam in the middle, hanging steel mesh and spraying concrete to form a continuous reinforcement surface;

[0022] S6, constructing the first support beam in the middle;

[0023] S7. Excavate to the bottom elevation of the second supporting beam in the middle, hang steel mesh and spray concrete to form a continuous reinforcement surface;

[0024] S8, constructing the second support beam in the middle;

[0025] S9. Repeat steps S7-S8 until the construction of all the support beams is completed.

[0026] Preferably, the S1 further includes:

[0027] By introducing three-dimensional finite element analysis, the deformation of the foundation pit, the stress of the pile-supporting unit and the response of the surrounding environment are simulated to determine the pile diameter, pile spacing, embedding depth of the retaining piles and supporting piles, the size of the support beam, and the spacing between adjacent combined piles.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. In the triangular pile-support structure of the present invention, the lateral pressure borne by the retaining piles is transmitted to the composite piles through the support beams. At the same time, the load is also transmitted inside the composite piles through the support beams, thereby supporting the foundation pit. Therefore, the length of the support beam required for the triangular pile-support structure of the present invention is significantly shorter than that of the support beam in the support system, which effectively reduces the thermal expansion and contraction effect of the support beam caused by changes in ambient temperature and reduces the damage of the internal stress to the pile-support structure.

[0030] 2. The composite piles are connected into a triangular structure through support beams. Reasonable distribution of connection points reduces local stress concentration, so that the support beams between the composite piles and the retaining piles form a complete mechanical system, which can more evenly distribute the thrust of the side wall of the foundation pit and enhance the deformation resistance and stability of the overall structure.

[0031] 3. The position and triangular geometric design of the combined piles can optimize the space utilization inside the foundation pit, reduce the space conflict with the existing underground structure, and have flexible layout, which is suitable for large-area foundation pits located in dense urban centers.

[0032] 4. The triangular pile support structure of the present invention forms an independent mechanical system by combining piles and retaining piles, which reduces the dependence on the bearing capacity of the soil and overcomes the limitations of the anchor support structure or the double-row pile support structure in soft soil conditions. It significantly improves the adaptability and stability of ultra-large-area foundation pit support, simplifies the construction process, and is efficient, economical and safe.

[0033] 5. The triangular pile support structure in the present invention can realize the overall excavation and support work of a large-area foundation pit, without the need for zoning and compartmentalization operations, reducing construction time, reducing the long-term occupation of manpower, machinery and resources, significantly saving total costs and improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention is described in detail below with reference to the embodiments and accompanying drawings, wherein:

[0035] Figure 1 It is a schematic diagram of a triangular pile-supported structure;

[0036] Figure 2 It is a plan view of the combined pile;

[0037] Figure 3 It is a schematic cross-sectional view of a composite pile.

[0038] 1. Support beam; 2. Support piles; 3. Guard piles; 4. Inner wall of foundation pit; 5. Pit bottom. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar components or components with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0040] In one embodiment, a triangular pile support structure includes pile support units such as Figure 1-3 As shown, the pile support unit includes a composite pile, a plurality of retaining piles 3 and a plurality of support beams 1. The plurality of retaining piles 3 are evenly distributed on the inner wall 4 of the foundation pit. The plurality of retaining piles 3 are arranged in a row along the length direction of the inner wall of the foundation pit. Two adjacent retaining piles 3 are connected by a support beam 1. The retaining piles 3 are made of high-strength materials (such as reinforced concrete) and are used to directly bear the lateral thrust of the soil on the side wall of the foundation pit. The composite piles are arranged inside the foundation pit, the composite piles are directly opposite to the retaining piles 3, and the composite piles are connected to the retaining piles 3 by the support beam 1. The composite piles include three retaining piles 2, and the three retaining piles 2 are connected in sequence by the support beam 1 to form a triangle, forming a stable geometric frame for enhancing the mechanical properties of the overall support system. The three retaining piles 2 are respectively located at the three vertices of the triangle.

[0041] The support beam 1 connects multiple retaining piles 3 into a straight line, connects the composite piles with the retaining piles 3, and connects the three supporting piles 2 into a closed triangular frame. The support beam 1 not only provides additional rigid support for the retaining piles 3, but also forms a force transmission network in the entire foundation pit, so that the thrust of the side wall of the foundation pit can be evenly distributed to the composite piles and the support beam 1. Among them, the number of retaining piles 3 of a pile support unit can be 10, 11, 12, etc., such as 10 retaining piles 3 are arranged in a row along the inner wall 4 of the foundation pit, and the composite piles are arranged inside the foundation pit opposite to each other. The number and spacing of the retaining piles 3 of a pile support unit are determined according to the actual foundation pit size, force, bearing capacity of the retaining piles 3, etc. The bottoms of the supporting piles 2 and the retaining piles 3 extend into the bottom 5 of the foundation pit.

[0042] In the triangular pile support structure of this embodiment, the lateral pressure carried by the retaining pile 3 is transmitted to the composite pile through the support beam 1, and the load is also transmitted inside the composite pile through the support beam 1, so that the support of the foundation pit can be achieved. Therefore, the length of the support beam 1 required for the triangular pile support structure in this embodiment is significantly shorter than the length of the support beam 1 in the support support system, which effectively reduces the thermal expansion and contraction effect of the support beam 1 caused by the change of ambient temperature and reduces the damage of the internal stress to the pile support structure. Moreover, the composite piles are connected into a triangular structure through the support beam 1, and the reasonable distribution of the connection points reduces the local stress concentration, so that the support beam 1 between the composite pile and the retaining pile 3 forms a complete mechanical system, which can more evenly distribute the thrust of the side wall of the foundation pit and enhance the deformation resistance and stability of the overall structure. In addition, the position of the composite pile and the triangular geometric design can optimize the space utilization inside the foundation pit, reduce the space conflict with the existing underground structure, and have flexible layout, which is suitable for large-area foundation pits located in dense urban centers.

[0043] The triangular pile support structure in this embodiment forms an independent mechanical system by combining piles and retaining piles 3, which reduces the dependence on the bearing capacity of the soil, overcomes the limitations of anchor support structures or double-row pile support structures in soft soil conditions, and significantly improves the adaptability and stability of large-area foundation pit support, while simplifying the construction process, making it efficient, economical and safe. The triangular pile support structure in this embodiment can realize the overall excavation and support of large-area foundation pits, without the need for zoning and compartmentalization operations, reducing construction time, reducing the long-term occupation of manpower, machinery and resources, significantly saving total costs, and improving economic benefits.

[0044] The triangular pile support structure in this embodiment has a composite pile formed by three supporting piles 2 to form a triangle. Due to the geometric characteristics of the triangle, its mechanical analysis is more intuitive, the calculation model is simpler, and the complexity of the design is reduced. Moreover, based on the basic geometric characteristic of the triangle being stable, the triangular composite pile can provide a stable support frame. When subjected to the lateral thrust of the soil on the side wall of the foundation pit, the three vertices of the triangle (i.e., the three supporting piles 2) can effectively resist the external force and form a stable force system. In addition, the number of supporting piles 2 and supporting beams 1 in the triangular pile support structure is relatively small, the construction difficulty is low, the footprint is small, and it is suitable for a variety of working conditions.

[0045] In one embodiment, along the arrangement direction of a row of retaining piles 3, the length of the triangle is less than the length of a row of retaining piles 3. The retaining piles 3 arranged in a row are connected to the composite piles through the support beam 1, forming a T-shaped support structure. The retaining piles 3 arranged in a straight line form the top horizontal structure of the T-shape, and the support beam 1 and the composite piles with a smaller length form the lower vertical structure of the T-shape. The retaining piles 3 are arranged along the inner wall of the foundation pit to form a rigid base, which can directly withstand the lateral soil pressure of the side wall of the foundation pit. Through the closed geometric characteristics of the triangle and the basic geometric characteristics of stability, the triangular composite piles use the support beam 1 to evenly transfer the lateral thrust to the internal structure to avoid the problem of concentrated force in a single direction. The transverse structure of the T-type support structure bears the main soil pressure, and the vertical structure further disperses and transmits the force to the inside of the foundation pit through the support beam 1 and the combined pile. Through the joint action of the top horizontal line (guard pile 3) and the lower vertical structure (triangle and support beam 1), the thrust of the side wall of the foundation pit is evenly transmitted to the combined pile and support beam 1, avoiding excessive force at a single point and improving the uniformity of the overall force. Under dynamic disturbances such as construction around the foundation pit or subway vibration, the rigid frame of the T-type structure can provide better anti-disturbance ability and reduce the risk of local instability caused by vibration.

[0046] In one embodiment, Figure 2 As shown, the three supporting piles 2 of the combined pile form an isosceles triangle. The horizontal force transmitted by the supporting piles 3 can be more evenly transmitted upward to the supporting piles 2 at the vertex along the two waists (support beams 1) of the isosceles triangle. The base of the isosceles triangle is parallel to the supporting piles 3 arranged in a row, and the base of the isosceles triangle is closer to the supporting piles 3 relative to its vertex. Compared with the solution in which the vertex of the isosceles triangle is closer to the supporting piles 3, the arrangement of this embodiment greatly reduces the soil between the piles, so that the shadow effect of the supporting piles 2 is not obvious, which is more conducive to exerting the horizontal force resistance of the supporting piles 2, thereby enhancing the horizontal force resistance capacity of the entire combined pile and the pile-supported structure, and the structural stability is improved.

[0047] In one embodiment, the vertex angle of the isosceles triangle is 60 to 90 degrees, that is, the shape of the isosceles triangle is relatively regular, not particularly sharp (the vertex angle is less than 60 degrees) nor particularly flat (the vertex angle is greater than 90 degrees), and the length ratio of its two waists (the support beam 1 connecting the support piles 2) to the bottom edge (the edge close to the surrounding pile 3) is within a certain range, so that the geometric shape of the entire composite pile is relatively stable, and the lateral thrust transmitted from the surrounding pile 3 can be more evenly distributed to the three support piles 2, avoiding excessive deformation or damage of a certain support pile 2 due to sharing too much lateral force, so that the composite pile as a whole can more effectively resist lateral thrust. In addition, during the construction process, the vertex angle of 60 to 90 degrees makes it easy for construction machinery to easily complete the installation of the support piles 2 and the support beam 1, and the construction machinery is more easily aligned to the predetermined position, reducing construction errors and improving construction accuracy.

[0048] In one embodiment, along a direction perpendicular to a row of retaining piles 3, two retaining piles 2 on the bottom edge are connected to the retaining piles 3 through a support beam 1. The two retaining piles 2 are connected to the retaining piles 3 through the support beam 1, forming the first force transmission path inside the foundation pit support, which can make the lateral thrust of the foundation pit side wall soil borne by the retaining piles 3 be transmitted to the combined piles more directly and efficiently, thereby enhancing the collaborative working ability of the entire support structure, making the force transmission inside the structure smoother and more uniform, and improving the structure's resistance to lateral forces. The connection method is relatively simple and direct, which is convenient for construction personnel to operate, can improve construction efficiency, and reduce construction time and cost. At the same time, since the connection method is clear, it is also conducive to quality control and precision control during the construction process, further ensuring the construction quality of the support structure.

[0049] In one embodiment, the pile support unit also includes a reinforcement beam located inside the triangle, and the two ends of the reinforcement beam are respectively connected to the support piles 2 and the support beam 1. The reinforcement beam further connects the support piles 2 and the support beam 1 on the triangle, and together with the original support beam 1, a more complex and stable internal structural framework is constructed, which effectively enhances the connection strength inside the composite pile. When bearing the lateral thrust of the soil on the side wall of the foundation pit, the support piles 2 are restrained and supported by each other through the reinforcement beam, which reduces the displacement and deformation possibility of a single support pile 2, and significantly improves the stability of the composite pile as a whole, so as to better bear the load transmitted from the retaining piles 3.

[0050] In one embodiment, the triangular pile support structure includes a plurality of pile support units, and the plurality of rows of retaining piles 3 of the plurality of pile support units are evenly laid on the inner wall 4 of the foundation pit by connecting the end to the end with the support beam 1. Each pile support unit includes components such as a combined pile, a plurality of retaining piles 3, and a support beam 1 connecting them. A plurality of such pile support units are combined together to form a support system covering a large area of ​​the inner wall of the foundation pit. The support beams 1 are all short in length, have low internal stress, high reliability, and high flexibility in layout, and can better adapt to foundation pits of various shapes and areas.

[0051] In one embodiment, two adjacent supporting piles 2 on two adjacent bottom edges are connected by a supporting beam 1, that is, a new connection is built between the bottom edges of two adjacent triangular combined piles, and the two triangles are closely connected at the bottom edge position, so that the connection between multiple pile support units is closer, forming a more continuous overall support system, and the integrity of the entire pile support structure is significantly improved. When facing complex geological conditions or external dynamic loads (such as earthquakes, surrounding construction vibrations, etc.), this integrity can make the force more evenly transmitted and dispersed in the entire pile support structure, reduce the possibility of local deformation and damage, optimize the force transmission path, improve structural redundancy, and improve the stability of the structure under complex working conditions.

[0052] In one embodiment, a construction method of the triangular pile support structure in the above embodiment comprises:

[0053] S1. Analyze the geological survey report, find out the geological conditions, determine the pile diameter, pile spacing, embedding depth and support beam size of the retaining piles and support piles according to the bottom elevation requirements of the foundation pit, and determine the spacing of adjacent composite piles. Among them, analyzing the geological survey report specifically refers to finding out the key information such as the stratum structure, physical and mechanical parameters of the soil layer and groundwater level through the survey data, and obtaining the lateral total earth pressure of the entire foundation pit, such as using the incremental method to calculate the horizontal thrust T of the side wall of the foundation pit on all piles in the pit. The pile diameter can be determined based on the foundation pit depth and earth pressure calculation. The pile spacing is used to ensure that effective inter-pile soil collaborative support is formed between the piles. The pile spacing can be set to 2.5-6 times the pile diameter; the embedding depth is determined according to the geological conditions and anti-slip requirements. The spacing of adjacent composite piles is reasonably arranged according to the width of the foundation pit, the bearing capacity of a single composite pile and the force requirements to form an effective support system.

[0054] S2. Use a rotary drilling rig or impact drilling rig to drill holes in retaining piles and supporting piles, and carry out the construction of retaining piles and supporting piles. Specifically, after the drilling is completed, the steel cage is installed and concrete is poured to form retaining piles and supporting piles.

[0055] S3. The bottom elevation of the supporting beam from the first layer of earth excavation to the top.

[0056] S4. Carry out the construction of the top support beam, specifically the reinforcement binding and formwork installation of the top support beam, to ensure that the size and position of the beam meet the design requirements. Through the connection of the support beam with the retaining piles and support piles, a preliminary rigid support structure is formed.

[0057] S5. Excavate to the bottom elevation of the first supporting beam in the middle, hang steel mesh and spray concrete to form a continuous reinforcement surface to improve the anti-slip ability of the side wall.

[0058] S6. Carry out the construction of the first middle support beam. Complete the binding, formwork installation and concrete pouring of the first middle support beam in the same way as the top support beam.

[0059] S7. Excavate to the bottom elevation of the second supporting beam in the middle, hang steel mesh and spray concrete to form a continuous reinforcement surface to further improve the anti-slip ability of the side wall.

[0060] S8. Carry out the construction of the second middle support beam. Complete the binding, formwork installation and concrete pouring of the second middle support beam in the same way as the top support beam.

[0061] S9, repeat steps S7-S8 until all the support beams are constructed. According to the method of steps S7-S8, excavate and construct layer by layer until all the support beams of the triangular pile support structure are completed.

[0062] The construction method in this embodiment ensures the mechanical properties and construction safety of the triangular pile support structure through layered excavation and segmented construction of multiple support beams, combined with shotcrete reinforcement measures. This method is suitable for complex geological conditions and large-scale foundation pit projects, can significantly improve construction efficiency and economy, while minimizing construction risks and environmental impacts, and is an efficient and reliable foundation pit support construction method.

[0063] In one embodiment, S1 further includes: by introducing three-dimensional finite element analysis, simulating the deformation of the foundation pit, the stress of the pile support unit and the response of the surrounding environment, determining the pile diameter, pile spacing, embedding depth, size of the support beam, and the spacing between adjacent combined piles of the retaining piles and the supporting piles. Specifically including:

[0064] S11. Three-dimensional finite element modeling. Establish a comprehensive three-dimensional model of the foundation pit, retaining piles, supporting piles, supporting beams and the surrounding environment, taking into account influencing factors such as geological conditions, groundwater level and construction procedures; reasonably set the boundary conditions of the model (such as fixed boundaries and free boundaries) to ensure the accuracy of the simulation; simulate the interaction between retaining piles and supporting piles and the surrounding soil through finite element analysis to evaluate the stress state and deformation characteristics of the structure.

[0065] S12. Multi-condition analysis. The key working conditions of the foundation pit during excavation (such as different excavation depths and different support beam installation stages) are simulated step by step; special conditions such as rainfall and groundwater level fluctuations that may affect the stability of the foundation pit are considered.

[0066] S13. Output analysis results. Simulate the horizontal displacement of the side wall of the foundation pit, the deformation law of the retaining piles and the supporting piles, calculate the stress distribution and maximum stress position of the supporting piles, retaining piles and supporting beams, and evaluate the impact of the foundation pit construction on the surrounding surface settlement, deformation of underground pipelines and existing building structures.

[0067] S14. Design optimization. According to the analysis results, adjust the pile diameter, pile spacing, and embedment depth to achieve the best mechanical properties, optimize the cross-sectional size and layout of the support beam, and optimize the spacing between adjacent combined piles: ensure the overall stability of the support system while saving material and construction costs.

[0068] In the description of this specification, if the terms "embodiment one", "this embodiment", "in an embodiment" and the like appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in the invention or at least one embodiment or example of the invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example; moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in an appropriate manner.

[0069] In the description of this specification, the terms "connect", "install", "fix", "set", "have", etc. are all understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0070] In the description of this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0071] The above description of the embodiments is to facilitate ordinary technicians in the technical field to understand and apply the technology of this case. People familiar with the technology in this field can obviously easily make various modifications to these examples and apply the general principles described here to other embodiments without creative work. Therefore, this case is not limited to the above embodiments. Modifications to the following situations should all be within the scope of protection of this case: ① A new technical solution implemented based on the technical solution of the present invention and combined with existing common knowledge, the technical effect produced by the new technical solution does not exceed the technical effect of the present invention; ② The equivalent replacement of some features of the technical solution of the present invention by using known technology, the technical effect produced is the same as the technical effect of the present invention; ③ The technical solution of the present invention can be expanded, and the substantive content of the expanded technical solution does not exceed the technical solution of the present invention; ④ The equivalent transformation made by using the contents of the description and drawings of the present invention is directly or indirectly applied to other related technical fields.

Claims

1. A triangular pile support structure, characterized in that: The invention comprises a pile support unit, wherein the pile support unit comprises: A plurality of retaining piles, wherein the plurality of retaining piles are arranged in a row along the inner wall of the foundation pit; A composite pile, which is arranged inside the foundation pit and directly faces a row of the retaining piles, and the composite pile includes three retaining piles; A plurality of support beams, two adjacent retaining piles are connected by the support beams, the combined piles are connected to the retaining piles by the support beams, three retaining piles are connected in sequence by the support beams to form a triangle, and the three retaining piles are respectively located at the three vertices of the triangle.

2. The triangular pile support structure according to claim 1, characterized in that: Along the arrangement direction of a row of the retaining piles, the length of the triangle is smaller than the length of a row of the retaining piles.

3. The triangular pile support structure according to claim 2, characterized in that: The three supporting piles of the combined pile form an isosceles triangle, and the bases of the isosceles triangle are parallel and close to the surrounding piles arranged in a row.

4. The triangular pile support structure according to claim 3, characterized in that: The vertex angle of the isosceles triangle is 60 degrees to 90 degrees.

5. The triangular pile support structure according to claim 4, characterized in that: Along a direction perpendicular to a row of the retaining piles, two of the retaining piles on the bottom edge are connected to the retaining piles via the support beam.

6. The triangular pile-supported structure according to any one of claims 1 to 5, characterized in that: The pile support unit also includes a reinforcement beam located inside the triangle, and two ends of the reinforcement beam are respectively connected to the support pile and the support beam.

7. The triangular pile support structure according to any one of claims 3 to 5, characterized in that: It comprises a plurality of pile-supporting units, wherein a plurality of rows of retaining piles of the plurality of pile-supporting units are connected end to end through the supporting beams and are evenly laid on the inner wall of the foundation pit.

8. The triangular pile support structure according to claim 7, characterized in that: Two adjacent supporting piles on two adjacent bottom edges are connected by the supporting beam.

9. The construction method of the triangular pile support structure according to any one of claims 1 to 8, characterized in that: The method comprises: S1. Analyze the geological survey report, find out the geological conditions, determine the pile diameter, pile spacing, embedding depth of the retaining piles and supporting piles and the size of the support beam according to the bottom elevation requirements of the foundation pit, and determine the spacing between adjacent combined piles; S2. Use a rotary drilling rig or an impact drilling rig to drill holes in the retaining piles and the supporting piles, and construct the retaining piles and the supporting piles; S3, the bottom elevation of the supporting beam from the first layer of earth excavation to the top; S4, constructing the support beam at the top; S5, excavating to the bottom elevation of the first supporting beam in the middle, hanging steel mesh and spraying concrete to form a continuous reinforcement surface; S6, constructing the first support beam in the middle; S7. Excavate to the bottom elevation of the second supporting beam in the middle, hang steel mesh and spray concrete to form a continuous reinforcement surface; S8, constructing the second support beam in the middle; S9. Repeat steps S7-S8 until the construction of all the support beams is completed.

10. The construction method according to claim 9, characterized in that: The S1 further comprises: By introducing three-dimensional finite element analysis, the deformation of the foundation pit, the stress of the pile-supporting unit and the response of the surrounding environment are simulated to determine the pile diameter, pile spacing, embedding depth of the retaining piles and supporting piles, the size of the support beam, and the spacing between adjacent combined piles.

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