Pentagonal pile supporting structure and construction method

Abstract

The invention relates to a pentagonal 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 five 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 corresponding supporting beams, and the five supporting piles are sequentially connected through the supporting beams to form a pentagon and located at the five vertexes of the pentagon 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 pentagonal 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 pentagonal pile support structure and a construction method.

[0005] The technical solution adopted by the present invention is a pentagonal 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 five 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, five retaining piles are connected in sequence by the support beams to form a pentagon, and the five retaining piles are respectively located at the five vertices of the pentagon.

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

[0010] Preferably, the four supporting piles of the combined piles form a rectangle, one side of the rectangle is parallel to the surrounding piles arranged in a row, and the fifth supporting pile is located on a side of the rectangle away from the surrounding piles.

[0011] Preferably, the fifth supporting pile and the connecting line of the two adjacent supporting piles form an angle of 60 to 90 degrees.

[0012] Preferably, along a direction perpendicular to a row of the retaining piles, two retaining piles close to the retaining piles are connected to the retaining piles through the supporting beam.

[0013] Preferably, the two retaining piles close to the retaining piles are also connected to the retaining piles at both ends of a row of the retaining piles through the support beam.

[0014] Preferably, the pile-supporting unit further comprises a reinforcement beam located inside the pentagon, and two sides of the reinforcement beam are respectively connected to one of the support piles.

[0015] 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.

[0016] The present invention also proposes a construction method of the above-mentioned pentagonal 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 comprises:

[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 pentagonal 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 pentagonal pile support structure of the present invention is significantly shorter than that of the support beam in the bracing 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 pentagonal structure through support beams. The 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 of the combined piles and the pentagonal geometric design can optimize the space utilization inside the foundation pit, reduce the space conflict with the existing underground structure, and have flexible layout, making it suitable for large-area foundation pits located in dense urban centers.

[0032] 4. The pentagonal 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 pentagonal pile support structure of 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 pentagonal pile-supported structure;

[0036] Figure 2 It is a cross-section of a pentagonal pile-supported structure;

[0037] Figure 3 It is the plan view of the composite pile;

[0038] Figure 4 It is a cross-sectional view of a composite pile.

[0039] 1. Support beam; 2. Support piles; 3. Guard piles; 4. Inner wall of foundation pit; 5. Pit bottom. DETAILED DESCRIPTION

[0040] 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.

[0041] In one embodiment, a pentagonal 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 pile is arranged inside the foundation pit, the composite pile is directly opposite to the retaining pile 3, and the composite pile is connected to the retaining pile 3 by the support beam 1. The composite pile includes five retaining piles 2, and the five retaining piles 2 are connected in sequence by the support beam 1 to form a pentagon, forming a stable geometric frame for enhancing the mechanical properties of the overall support system. The five retaining piles 2 are respectively located at the five vertices of the pentagon.

[0042] 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 five supporting piles 2 into a closed pentagonal 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 11 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 them. 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.

[0043] In the pentagonal 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 pentagonal 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 pentagonal 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 pentagonal 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.

[0044] The pentagonal 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 pentagonal 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.

[0045] In one embodiment, along the arrangement direction of a row of the retaining piles 3, the length of the pentagon is less than the length of a row of the retaining piles 3. The retaining piles 3 arranged in a row are connected to the composite piles through the support beam 1 to form 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 shorter 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 pentagon, the pentagonal composite pile uses 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 (pentagon 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 3-4 As shown, the four supporting piles 2 of the combined piles form a rectangle, and one side of the rectangle is parallel to the surrounding piles 3 arranged in a row, which reduces the construction difficulty, makes the force transmission clearer, and simplifies the calculation. The fifth supporting pile 2 is located on the side of the rectangle away from the surrounding piles 3, so that the five supporting piles 2 are arranged in three rows in a direction perpendicular to the rows of surrounding piles 3. The fifth supporting pile 2 is located in the row farthest from the surrounding piles 3, which greatly reduces the soil between the piles, the shadow effect of the supporting piles 2 is not obvious, and the supporting piles 2 have stronger resistance to horizontal forces, which improves the stiffness and stability of the overall pentagonal pile support structure. In addition, the fifth supporting pile 2 and the two adjacent supporting piles 2 form a stable triangular frame, which further enhances the ability of the overall structure to resist horizontal thrust.

[0047] In one embodiment, the fifth support pile 2 is connected to its two adjacent support piles 2 to form an angle of 60 to 90 degrees. At this time, the distribution of the lateral thrust transmitted to the fifth support pile 2 by the four support piles 2 of the encircling rectangle is more uniform, which greatly improves the ability of the fifth support pile 2 to share the lateral force. At the same time, the 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, reduces construction errors, and improves the safety of the pentagonal pile support structure.

[0048] In one embodiment, two retaining piles 2 close to a row of retaining piles 3 are connected to the retaining piles 3 through a support beam 1 in a direction perpendicular to the retaining piles 3. 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 enables the lateral thrust of the soil on the side wall of the foundation pit borne by the retaining piles 3 to 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 two retaining piles 2 near the retaining piles 3 are also connected to the retaining piles 3 at both ends of a row of retaining piles 3 through the support beam 1, that is, the middle and both ends of a row of retaining piles 3 are connected to the retaining piles 3 through the support beam 1, which further improves the force transmission network, so that the lateral thrust of the side wall of the foundation pit can be more comprehensively and evenly transmitted from the retaining piles 3 to the combined piles, avoiding the local concentration of force during the transmission process, and improving the force uniformity of the entire pile support structure. The connection method in this embodiment connects the retaining piles 3 and the combined piles more closely together, so that the support structure forms a more organic whole in plane and space, forming a spatial force system, and improving the spatial collaborative working ability of the structure. In addition, the connection method in this embodiment increases the force transmission path. During long-term use, even if some components are damaged or degraded to a certain extent, due to the existence of multiple force transmission paths and high structural redundancy, the entire pile support structure can still maintain good bearing capacity and stability, reducing the possibility of overall structural damage caused by failure of local components.

[0050] In other embodiments, two retaining piles 2 close to the retaining piles 3 are also connected to the retaining piles 3 near both ends of a row of retaining piles 3 through the support beam 1, which can also improve the force uniformity of the entire pile support structure.

[0051] In one embodiment, the pile support unit also includes a reinforcement beam located inside the pentagon, and a support pile 2 is connected to each side of the reinforcement beam. The reinforcement beam further connects the support piles 2 inside the pentagon, 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 pile 3.

[0052] In one embodiment, the pentagonal pile support structure includes a plurality of pile support units, and a plurality of rows of retaining piles 3 of the plurality of pile support units are connected end to end by support beams 1 and evenly laid on the inner wall 4 of the foundation pit. Each pile support unit includes components such as a combined pile, a plurality of retaining piles 3, and support beams 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 layout flexibility, and can better adapt to foundation pits of various shapes and areas.

[0053] In one embodiment, the support beam 1 can be arranged in multiple layers along the direction of gravity, such as including a top crown beam, a multi-layer waist beam in the middle, etc. The arrangement of the multi-layer support beam 1 transforms the support structure from a plane support to a three-dimensional support system. The top crown beam connects the retaining piles 3 and the composite piles of each pile support unit into one at the top, and the multi-layer waist beam in the middle further strengthens the lateral connection between the retaining piles 3 and the composite piles at different heights, greatly improving the spatial stability of the entire pile support structure, enabling it to more effectively resist the lateral pressure of the soil at different heights of the side wall of the foundation pit and other external loads. The specific number of layers of the support beam 1 is determined based on the excavation period, the requirements for the displacement of the pile top, and the stress of the foundation pit.

[0054] In one embodiment, a construction method of the pentagonal pile support structure in the above embodiment comprises:

[0055] 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.

[0056] S2. Use a rotary drilling rig or impact drilling rig to drill holes for 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.

[0057] S3. The bottom elevation of the supporting beam from the first layer of earth excavation to the top.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] S9, repeating steps S7-S8 until all the support beams are constructed. According to the method of steps S7-S8, excavation and construction are performed layer by layer until all the support beams of the pentagonal pile support structure are completed.

[0064] The construction method in this embodiment ensures the mechanical properties and construction safety of the pentagonal 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.

[0065] 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:

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 pentagonal 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 five 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, five retaining piles are connected in sequence by the support beams to form a pentagon, and the five retaining piles are respectively located at the five vertices of the pentagon.

2. The pentagonal 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 pentagon is smaller than the length of a row of the retaining piles.

3. The pentagonal pile support structure according to claim 2, characterized in that: The four supporting piles of the combined piles form a rectangle, one side of the rectangle is parallel to the surrounding piles arranged in a row, and the fifth supporting pile is located on a side of the rectangle away from the surrounding piles.

4. The pentagonal pile support structure according to claim 3, characterized in that: The fifth supporting pile and the connecting line with the two adjacent supporting piles form an angle of 60 to 90 degrees.

5. The pentagonal pile support structure according to claim 4, characterized in that: Along a direction perpendicular to a row of the retaining piles, two retaining piles close to the retaining piles are connected to the retaining piles through the supporting beam.

6. The pentagonal pile support structure according to claim 4, characterized in that: The two retaining piles close to the retaining piles are also connected to the retaining piles at both ends of a row of retaining piles through the support beam.

7. The pentagonal pile-supported structure according to any one of claims 1 to 6, characterized in that: The pile support unit also includes a reinforcement beam located inside the pentagon, and two sides of the reinforcement beam are respectively connected to one of the support piles.

8. The pentagonal pile-supported structure according to any one of claims 1 to 6, 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.

9. The construction method of a pentagonal 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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