Method and system for reducing rigidity of pile bottom section and optimizing single pile foundation

Abstract

The invention relates to the technical field of single pile foundations, and provides a method and system for optimizing a single pile foundation through rigidity reduction of a pile bottom section, and the method comprises the steps that for the pile foundation under the horizontal load effect, a pile foundation analysis model is established, pile foundation related parameters meeting other requirements except the pile horizontal displacement curve shape requirement are determined, and an original pile foundation scheme is obtained; when the pile foundation meets the suitable rigidity reduction working condition, the piles within a certain buried depth range are taken upwards from the pile bottoms to serve as the pile rigidity reduction range, in the pile rigidity reduction range, relevant parameters of the pile foundation are optimized to reduce the rigidity of the pile foundation, and a rigidity reduction pile foundation scheme is obtained; the pile foundation meets the pile horizontal displacement curve shape requirement and other requirements; and according to machining and construction conditions, a pile foundation design scheme is selected from the rigidity reduction pile foundation scheme and the original pile foundation scheme. The problems of increasing the depth of the pile in the soil and increasing the investment cost are avoided, and the pile foundation cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of monopile foundation technology, and in particular relates to a method and system for optimizing monopile foundations by reducing the stiffness of the pile bottom section. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Monopile foundations are widely used in new energy support structures, such as offshore wind turbine monopile foundations and offshore photovoltaic support foundations. These foundations primarily bear horizontal forces and overturning moments. The Py method is widely used in calculations, which approximates the soil as a nonlinear spring to calculate the horizontal deformation of the pile foundation. Referring to the energy industry standard "Design Code for Wind Turbine Foundations of Offshore Wind Farm Projects," there are generally two methods for determining the depth of a monopile's penetration into the soil using the Py method: (1) A vertical tangent appears in the horizontal displacement curve of a single pile; (2) The displacement of the mud surface of the pile foundation remains basically unchanged as the pile penetration depth increases.

[0004] In actual calculation and analysis, because criterion (2) does not give a precise definition of "basically unchanged", it is often impossible to define in actual application. Therefore, criterion (1) is mainly used in the design of single pile foundations.

[0005] However, using only the vertical tangent as the criterion for determining the pile penetration depth can lead to very serious waste. For example, when the bending stiffness of a single pile foundation is large but the load is not large (often occurring in single pile foundations under non-stress-controlled conditions such as modal stress or cracks), the stress in the pile body is relatively small and the horizontal displacement at the pile bottom is also very small, making it difficult to find a vertical tangent. If the pile penetration depth is strictly determined according to the vertical tangent, the pile penetration depth must be increased, resulting in a significant increase in the amount of pile foundation material used and causing very serious waste. Summary of the Invention

[0006] To address the technical problems mentioned above, this invention provides a method and system for optimizing single pile foundations by reducing the stiffness of the pile bottom section. Without increasing the pile penetration depth, the method reduces the bending stiffness of the pile body at the bottom section and verifies whether the stiffness-reduced pile scheme can simultaneously meet the shape of the pile's horizontal displacement curve and other requirements. This provides a way to avoid increasing the pile penetration depth and investment costs, thereby reducing the cost of the pile foundation.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides a method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section, comprising: For pile foundations under horizontal loads, establish a pile foundation analysis model, determine the relevant parameters of the pile foundation that meet the requirements other than the shape of the pile horizontal displacement curve, and obtain the original pile foundation scheme. When the pile foundation meets the applicable working conditions for stiffness reduction, a certain range of piles within a certain depth of soil penetration is selected from the pile bottom upwards as the pile stiffness reduction range. Within the pile stiffness reduction range, the relevant parameters of the pile foundation are optimized to reduce the stiffness of the pile foundation, thus obtaining the stiffness-reduced pile foundation scheme. After the pile foundation stiffness is reduced, the pile foundation meets the requirements for the shape of the pile horizontal displacement curve and other requirements. Based on the processing and construction conditions, the pile foundation design scheme is selected from the reduced stiffness pile foundation scheme and the original pile foundation scheme.

[0008] Furthermore, the applicable working conditions for reducing stiffness are: the pile horizontal deformation curve has no vertical tangent and the pile stress ratio is less than the threshold; or, the pile horizontal deformation curve has no vertical tangent and the bearing capacity margin is greater than the set value.

[0009] Furthermore, the pile foundation analysis model is established based on the Py method.

[0010] Furthermore, the relevant parameters of the pile foundation include the depth of penetration into the soil, the pile diameter, and the pile elastic modulus.

[0011] Furthermore, the requirement for the shape of the pile horizontal displacement curve means that the pile horizontal displacement curve has a vertical tangent.

[0012] Furthermore, the range of pile stiffness reduction is determined by the criterion that the bearing capacity meets the requirements and the vertical tangent of the pile's horizontal deformation occurs simultaneously.

[0013] Furthermore, the other requirements include load-bearing capacity and / or modal requirements.

[0014] A second aspect of the present invention provides a system for optimizing the stiffness of a single pile foundation by reducing the pile bottom section, comprising: The initialization module is configured to: for pile foundations under horizontal loads, establish a pile foundation analysis model, determine the relevant parameters of the pile foundation that meet the requirements other than the shape of the pile horizontal displacement curve, and obtain the original pile foundation scheme. The optimization module is configured to: when the pile foundation meets the applicable working conditions for stiffness reduction, select a certain pile depth range from the pile bottom upwards as the pile stiffness reduction range, optimize the relevant parameters of the pile foundation within the pile stiffness reduction range to reduce the stiffness of the pile foundation, and obtain a stiffness-reduced pile foundation scheme. After the pile foundation stiffness is reduced, the pile foundation meets the requirements for the shape of the pile horizontal displacement curve and other requirements. The selection module is configured to select a pile foundation design scheme from the stiffness-reduced pile foundation scheme and the original pile foundation scheme based on the processing and construction conditions.

[0015] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described above.

[0016] A fourth aspect of the present invention provides a computer device including a computer-readable storage medium, a processor, and a computer program stored on the computer-readable storage medium and executable on the processor, wherein the processor executes the program to implement the steps of the method for optimizing the stiffness reduction of a single pile foundation as described above.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention, without increasing the pile's penetration depth, causes a vertical tangent to appear on the pile's horizontal deformation curve, further determining whether the bearing capacity of the reduced stiffness section meets the requirements. If both the vertical tangent and bearing capacity of the reduced stiffness pile meet the requirements, it can be considered that both the reduced stiffness pile and the non-reduced stiffness pile meet the requirements, thereby avoiding the problems of increasing the pile's penetration depth and investment costs, and achieving a reduction in pile foundation costs. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a flowchart of a method for optimizing a single pile foundation by reducing the stiffness of the pile bottom section according to Embodiment 1 of the present invention; Figure 2 This is a comparison diagram of the horizontal displacement curves of the PHC pipe pile foundation before and after stiffness reduction in Embodiment 1 of the present invention. Figure 3 This is a comparison diagram of the horizontal displacement curves of the large-diameter steel pipe pile before and after stiffness reduction in Embodiment 1 of the present invention. Figure 4 This is a schematic diagram of the structure of a computer device according to Embodiment 4 of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0021] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] Example 1 This embodiment provides a method for optimizing a single pile foundation by reducing the stiffness of the pile bottom section.

[0023] Further analysis of the criteria (1) requires that the vertical tangent of the horizontal displacement curve of the pile body actually requires that the maximum negative horizontal displacement of the pile foundation (opposite to the mud surface displacement) be moved upward, so as to avoid it appearing at the bottom of the pile. When the pile foundation is deeply embedded in the soil, the maximum negative horizontal displacement appears at the bottom of the pile. As the pile is deeply embedded in the soil, the maximum negative horizontal displacement will eventually leave the bottom of the pile and move upward. At this time, the embedment depth meets the requirements. Therefore, the determination of the embedment depth of the pile foundation actually requires that the maximum negative horizontal displacement be moved upward and leave the bottom of the pile.

[0024] When determining the depth of a single pile foundation, in addition to ensuring that the horizontal deformation meets the requirements, the pile itself must also meet the bearing capacity requirements. Based on whether the horizontal deformation of the pile foundation shows a vertical tangent and whether the pile body meets the bearing capacity requirements, there are four cases for the depth of the pile foundation, as shown in Table 1.

[0025] Table 1. Four scenarios regarding the depth of pile foundation penetration.

[0026] This invention addresses the third scenario, where the horizontal displacement curve of the pile body lacks a vertical tangent but the pile bearing capacity meets the requirements. The conventional approach is to increase the pile's depth into the soil to create a vertical tangent for the horizontal displacement. While this method ensures the presence of a vertical tangent, it significantly increases the cost of the pile foundation. When the pile foundation stress is relatively low, this approach can lead to substantial waste.

[0027] To address this issue, we further analyze the third scenario and explore how, without increasing the pile's embedment depth, the distribution of the pile's bending stiffness can be altered to shift the maximum negative horizontal displacement upwards, resulting in a vertical tangent. In this case, the pile foundation can be configured with two options as needed: (a) Select the pile foundation scheme with modified pile stiffness; Alternatively, (b) adopt the original stiffness modification scheme, arguing that even without the presence of vertical tangents, the scheme without stiffness modification is safe because the stiffness reduction scheme is feasible.

[0028] For single piles with no vertical tangent in the horizontal displacement curve under horizontal force, sufficient bearing capacity, and low stress, this embodiment proposes a method to adjust the pile stiffness near the pile bottom to shift the maximum negative horizontal displacement upwards. This achieves the appearance of a vertical tangent in the horizontal deformation curve of the pile without increasing the pile's depth, further determining whether the bearing capacity of the reduced stiffness section meets the requirements. If the reduced stiffness pile has both a vertical tangent and sufficient bearing capacity, both the reduced stiffness pile and the non-reduced stiffness pile can be considered to meet the requirements. Furthermore, considering the ease of pile foundation production, either the reduced stiffness pile foundation or the non-reduced stiffness pile foundation scheme can be selected, thus avoiding the problems of increasing pile depth and investment costs, and achieving a reduction in pile foundation costs.

[0029] This embodiment provides a method for optimizing the stiffness of a single pile foundation by reducing the stiffness of the pile bottom section, such as... Figure 1 As shown, the main implementation steps are as follows: Step 1: Based on the soil mechanical parameters of the pile foundation and the load acting on the pile, initially select the pile foundation material and pile diameter (wall thickness). Establish a pile foundation analysis model based on the Py method. Through trial calculations, the pile foundation should initially meet other requirements except for the shape of the pile horizontal displacement curve. For example, photovoltaic PHC pipe piles should meet the ultimate bearing capacity and crack bearing capacity, and offshore wind power monopile foundations should meet the bearing capacity and modal requirements. At this time, the relevant parameters of the pile foundation include: soil penetration depth h, pile diameter D (or wall thickness t), and pile elastic modulus E.

[0030] Step 2: Determine the applicability and range of stiffness reduction methods for pile bottom.

[0031] If the results of step 1 show the following conditions: the horizontal deformation curve of the pile has no vertical tangent and the pile stress ratio is <0.6; or, the horizontal deformation curve of the pile has no vertical tangent and the bearing capacity margin is large, then take about 1 / 3 of the pile within the soil depth range from the pile bottom upwards to change the pile section stiffness.

[0032] Step 2 can be carried out according to the following process: Step 2.1: Determine the applicable working conditions for reducing stiffness: The horizontal deformation curve of the pile body has no vertical tangent, and the stress ratio of the pile body is less than 0.6 or the bearing capacity margin is large; Step 2.2: Determine the range of stiffness reduction for pile foundations: To determine the range of stiffness reduction for pile foundations, let the pile penetration depth be h. Analyze the pile stiffness reduction length parameters: Take 1 / 2, 1 / 2.5, 1 / 3, 1 / 3.5, 1 / 4, 1 / 4.5, and 1 / 5 of the penetration depth h from the pile bottom upwards as the range of pile stiffness reduction. Calculate the pile bearing capacity and horizontal deformation. Use the simultaneous occurrence of the bearing capacity requirement and the vertical tangent of the horizontal deformation of the pile as the criterion to find a suitable range of stiffness reduction. Based on the parameter analysis results of multiple different pile foundations, when the pile foundation stiffness reduction range is about 1 / 3 of the pile penetration depth, the internal force of the pile is generally small within this range, the pile bearing capacity margin is large, and it is easier to meet the pile bearing capacity and other requirements after stiffness reduction. At the same time, the length of the pile stiffness reduction is also more suitable, and it is easy for the vertical tangent of the horizontal deformation of the pile to appear. Therefore, the range of stiffness reduction for pile foundations is from the pile bottom to 1 / 3 of the pile penetration depth upwards.

[0033] Step 3: Determine the stiffness reduction ratio.

[0034] Within the range of pile reduction stiffness, the original pile foundation stiffness will be... EI The stiffness should be reduced to 0.3 to 0.9 times the original value. It is recommended to estimate the stiffness by reducing it to 0.5 times, 0.3 times (when no vertical tangent appears in the horizontal displacement at 0.5 times), or 0.7 times (when the bearing capacity is not satisfied at 0.5 times). The specific reduction ratio needs to be determined by trial calculation.

[0035] The method for determining the variable flexural stiffness EI of a pile foundation is as follows: Within the range of stiffness reduction, the flexural stiffness EI of the pile foundation is reduced to 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.1 times the original value, respectively. The bearing capacity and horizontal displacement curves of the pile foundation are calculated. If, after the change in flexural stiffness, the pile bearing capacity meets the requirements and the horizontal displacement of the pile shows a vertical tangent, then the flexural stiffness of the pile is considered to meet the requirements. Similar stiffness reduction analyses are performed on single piles of different diameters and materials under multiple working conditions, and the feasible stiffness reduction range is approximately 0.3 to 0.9 times the original flexural stiffness of the pile foundation.

[0036] Step 3 involves methods to change the pile foundation stiffness EI, including: Step (1): Change the moment of inertia I of the cross section. For common circular piles or circular pipe piles in engineering, the formula for calculating the moment of inertia I of the cross section is as follows: Round stake: ; Circular pipe piles: ; As shown in the above formula, changing the pile cross-sectional dimensions, such as the diameter D or wall thickness t of a circular pile, can change the moment of inertia I, thereby altering the pile stiffness. EI This requires reducing the stiffness of the pile foundation. EI Therefore, the diameter needs to be reduced. DOr reduce wall thickness t .

[0037] Step (2): Change the elastic modulus of the pile foundation E Elastic modulus E Closely related to the pile foundation material, changing E means using pile foundations made of two different materials. For example, the elastic modulus of commonly used steel is E=206GPa, while the elastic modulus of PHC pipe piles is generally taken as 20~40GPa. Considering that PHC piles are generally thicker than steel pipe piles and have a larger moment of inertia I than steel pipe piles, a combined pile structure of upper steel pipe and lower PHC pipe pile can be adopted.

[0038] Step 4: Keep the pile penetration depth unchanged, adjust the pile foundation size (diameter, wall thickness) or elastic modulus (material), change the stiffness of the pile bottom section, apply load to the pile foundation after stiffness reduction, calculate the pile foundation horizontal displacement curve shape, pile foundation bearing capacity, modal response values, etc., and find a pile foundation scheme that satisfies all the requirements of stiffness reduction.

[0039] Step 5: Under the condition of determining the current embedment depth, the pile stiffness can be changed to make the horizontal displacement curve of the pile body show a vertical tangent, and the pile bearing capacity and other response terms (such as modes) meet the requirements. At this time, the stiffness-reduced pile foundation scheme meets the requirements, and the cross section is smaller than the original pile foundation scheme, saving more material. It can be used as the final optimized design scheme. For the original pile foundation scheme, it can be considered as a reinforcement based on the stiffness-reduced scheme. Under the premise that the stiffness-reduced pile foundation scheme meets the requirements, even if the horizontal displacement curve of the original pile body does not show a vertical tangent, it also meets the requirements. Its advantage is to avoid the complex processing problem caused by the variable cross section of the pile foundation. Its disadvantage is that the material consumption is slightly increased compared with the stiffness-reduced scheme.

[0040] This embodiment provides a method for optimizing a single pile foundation by reducing the stiffness of the pile bottom section. Through stiffness reduction analysis of the pile bottom section, the selected stiffness reduction scheme reduces the pile size compared to the original pile foundation scheme, thereby reducing material costs. At the same time, the original pile foundation scheme without vertical tangent can also be selected, in which case there is no need to increase the pile penetration depth, thus achieving the goal of cost reduction.

[0041] The explanation will be based on two experiments, using fixed photovoltaic PHC monopile and large-diameter steel pipe pile as examples.

[0042] 1. Test of fixed photovoltaic monopile foundation.

[0043] Taking a fixed offshore photovoltaic (PHC) monopile foundation as an example, the pile protrusion height is 10.4m. The load application point is calculated at a protrusion height of 6.25m, the equivalent horizontal load is 82.9kN, and the overturning moment is 60.9kN.m. Following the optimization steps for reducing stiffness at the pile bottom section, the analysis is as follows: (1) Based on the geological conditions and load conditions, the pile foundation is preliminarily selected as PHC1000-130-AB with a pile foundation depth of 16m. The response under horizontal and overturning forces is calculated using the py method. At this time, the maximum bending moment of the pile body is 810kN.m, and the ultimate bending moment bearing capacity and crack resistance bending moment bearing capacity of the pile are 1457kN.m and 884kN.m, respectively, which meet the bearing capacity requirements.

[0044] (2) According to the calculation results of the previous step, the maximum position of the horizontal displacement curve of the pile body is at the bottom of the pile, that is, there is no vertical tangent. At the same time, the bearing capacity of the pile meets the requirements and the margin is sufficient. At this time, the stiffness reduction adjustment range is 5m from the bottom of the pile upwards, and the stiffness reduction range is about 31% of the soil depth. (3) PHC pipe piles were selected for the pile foundation in the stiffness reduction section. After trial calculation, the pile diameter was reduced while the wall thickness remained unchanged. The pile foundation specification was PHC800-130-A. At this time, the stiffness reduction ratio of the pile foundation was 0.46. (4) After stiffness reduction, the maximum bending moment in the stiffness-reduced section is 288 kN·m. The ultimate bending moment bearing capacity and crack-resistant bending moment bearing capacity of the pipe pile in the stiffness-reduced section are 612 kN·m and 408 kN·m, respectively, which meet the requirements. Meanwhile, a comparison of the horizontal displacement deformation curves of the pile body at the pile bottom section before and after stiffness reduction is shown in the figure below. Figure 2 As shown.

[0045] 5. By reducing the stiffness of the pile foundation within 5m above the pile bottom, the maximum negative displacement of the pile body moves away from the pile bottom and upwards. That is, the pile foundation scheme after stiffness reduction meets the deformation requirements, and the bearing capacity of the pile foundation after stiffness reduction also meets the requirements. At the same time, the pile cross-section of the original pile foundation scheme is larger than that of the pile foundation scheme with reduced stiffness, and the bearing capacity is stronger. Therefore, it shows that even if the horizontal displacement curve of the pile body has no vertical tangent, it is safe and can be selected.

[0046] Calculations show that, without reducing the stiffness of the pile bottom section and only increasing the pile penetration depth, the pile penetration depth must reach 19m for the vertical tangent to appear on the horizontal displacement curve. Table 2 compares the penetration depths of the three pile foundation schemes. It can be seen that by reducing the stiffness of the pile bottom section, schemes 1 and 2 are feasible. Compared to the traditional scheme 3, the penetration depth is optimized by 3m, reducing the cost of the pile foundation.

[0047] Table 2. Comparison of the embedment depth of the three pile foundation schemes in Experiment 1

[0048] 2. Experiment on a large-diameter steel pipe pile.

[0049] Taking a large-diameter monopile foundation as an example, the load application point is taken at a height of 1m above the mud surface, and the horizontal load is 30000kN. Following the optimization steps for reducing stiffness at the pile bottom section, the analysis is as follows: (1) Based on the geological conditions and load conditions, the preliminary analysis selected steel pipe piles with a diameter of 7m and a wall thickness of 73mm for the pile foundation. The pile foundation was inserted into the soil at a depth of 60m. The response under horizontal force was calculated using the py method. At this time, the maximum stress ratio of the pile body was 0.49, which met the bearing capacity requirements.

[0050] (2) Based on the calculation results of the previous step, it is confirmed that the maximum position of the horizontal displacement curve of the pile body is at the bottom of the pile, that is, there is no vertical tangent. At the same time, the pile bearing capacity meets the requirements and has sufficient margin. At this time, the stiffness reduction adjustment range is taken as 23m from the bottom of the pile upwards, and the stiffness reduction range is about 38% of the soil depth. (3) In the stiffness reduction section, with the material unchanged, the pile diameter and wall thickness were reduced. After trial calculation, a steel pipe pile diameter of 5.3m and a wall thickness of 50mm were selected. At this time, the stiffness reduction ratio was 0.3. (4) After stiffness reduction, the maximum stress ratio of the stiffness-reduced section is 0.9, and the bearing capacity meets the requirements. The following figure also shows a comparison of the horizontal displacement deformation curves of the pile body at the bottom section before and after stiffness reduction. Figure 3 As shown.

[0051] (5) By reducing the stiffness of the pile foundation within a range of 23m above the pile bottom, the maximum negative displacement of the pile body moves away from the pile bottom and upwards. That is, the pile foundation scheme after stiffness reduction meets the deformation requirements, and the bearing capacity of the pile foundation after stiffness reduction also meets the requirements. At the same time, the pile section of the original pile foundation scheme is larger than that of the pile foundation scheme with reduced stiffness, and the bearing capacity is stronger. Therefore, it shows that even if the horizontal displacement curve of the pile body has no vertical tangent, it is safe and can be selected.

[0052] Calculations show that, without reducing the stiffness of the pile bottom section and only increasing the pile penetration depth, the pile penetration depth must reach 64m for the vertical tangent to appear on the horizontal displacement curve. Table 3 compares the penetration depths of the three pile foundation schemes. It can be seen that by reducing the stiffness of the pile bottom section, schemes 1 and 2 are feasible. Compared to the traditional scheme 3, the penetration depth is optimized by at least 4m, reducing the cost of the pile foundation.

[0053] Table 3. Comparison of the embedment depth of the three pile foundation schemes in Experiment 2

[0054] Example 2 This embodiment provides a system for optimizing the stiffness of a single pile foundation by reducing the pile bottom section, comprising: The initialization module is configured to: for pile foundations under horizontal loads, establish a pile foundation analysis model, determine the relevant parameters of the pile foundation that meet the requirements other than the shape of the pile horizontal displacement curve, and obtain the original pile foundation scheme. The optimization module is configured to: when the pile foundation meets the applicable working conditions for stiffness reduction, select a certain pile depth range from the pile bottom upwards as the pile stiffness reduction range, optimize the relevant parameters of the pile foundation within the pile stiffness reduction range to reduce the stiffness of the pile foundation, and obtain a stiffness-reduced pile foundation scheme. After the pile foundation stiffness is reduced, the pile foundation meets the requirements for the shape of the pile horizontal displacement curve and other requirements. The selection module is configured to select a pile foundation design scheme from the stiffness-reduced pile foundation scheme and the original pile foundation scheme based on the processing and construction conditions.

[0055] It should be noted that each module in this embodiment corresponds one-to-one with each step in Embodiment 1, and their specific implementation processes are the same, so they will not be repeated here.

[0056] Example 3 This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in the method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described in Embodiment 1 above.

[0057] Example 4 This embodiment provides a computer device, such as... Figure 4 As shown, the system includes a computer-readable storage medium 1003, a processor 1001, a communication interface 1002, and a computer program stored on the computer-readable storage medium 1003 and executable on the processor 1001. The processor 1001, communication interface 1002, and computer-readable storage medium 1003 can be connected via a bus or other means. The communication interface 1002 is used to receive and send data. When the processor 1001 executes the program, it implements the steps in the method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described in Embodiment 1 above.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section, characterized in that, include: For pile foundations under horizontal loads, establish a pile foundation analysis model, determine the relevant parameters of the pile foundation that meet the requirements other than the shape of the pile horizontal displacement curve, and obtain the original pile foundation scheme. When the pile foundation meets the applicable working conditions for stiffness reduction, a certain range of piles within a certain depth of soil penetration is selected from the pile bottom upwards as the pile stiffness reduction range. Within the pile stiffness reduction range, the relevant parameters of the pile foundation are optimized to reduce the stiffness of the pile foundation, thus obtaining the stiffness-reduced pile foundation scheme. After the pile foundation stiffness is reduced, the pile foundation meets the requirements for the shape of the pile horizontal displacement curve and other requirements. Based on the processing and construction conditions, the pile foundation design scheme is selected from the reduced stiffness pile foundation scheme and the original pile foundation scheme.

2. The method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described in claim 1, characterized in that, The applicable working conditions for reducing stiffness are: the pile horizontal deformation curve has no vertical tangent and the pile stress ratio is less than the threshold; or, the pile horizontal deformation curve has no vertical tangent and the bearing capacity margin is greater than the set value.

3. The method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described in claim 1, characterized in that, The pile foundation analysis model is established based on the py method.

4. The method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described in claim 1, characterized in that, The relevant parameters of the pile foundation include the depth of penetration into the soil, the pile diameter, and the pile elastic modulus.

5. The method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described in claim 1, characterized in that, The requirement for the shape of the pile horizontal displacement curve is that the pile horizontal displacement curve has a vertical tangent.

6. The method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described in claim 1, characterized in that, The range of pile stiffness reduction is determined by the criterion that the bearing capacity meets the requirements and the vertical tangent of the pile's horizontal deformation occurs simultaneously.

7. The method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described in claim 1, characterized in that, Other requirements include load-bearing capacity and / or modal requirements.

8. A system for optimizing the stiffness of a single pile foundation by reducing the pile bottom section, characterized in that, include: The initialization module is configured to: for pile foundations under horizontal loads, establish a pile foundation analysis model, determine the relevant parameters of the pile foundation that meet the requirements other than the shape of the pile horizontal displacement curve, and obtain the original pile foundation scheme. The optimization module is configured to: when the pile foundation meets the applicable working conditions for stiffness reduction, select a certain pile depth range from the pile bottom upwards as the pile stiffness reduction range, optimize the relevant parameters of the pile foundation within the pile stiffness reduction range to reduce the stiffness of the pile foundation, and obtain a stiffness-reduced pile foundation scheme. After the pile foundation stiffness is reduced, the pile foundation meets the requirements for the shape of the pile horizontal displacement curve and other requirements. The selection module is configured to select a pile foundation design scheme from the stiffness-reduced pile foundation scheme and the original pile foundation scheme based on the processing and construction conditions.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described in any one of claims 1-7.

10. A computer device comprising a computer-readable storage medium, a processor, and a computer program stored on the computer-readable storage medium and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the method for optimizing the stiffness of a single pile foundation by reducing the pile bottom section as described in any one of claims 1-7.

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