A design method for low-cycle repeated loading tests on pile foundations simulating the incidence of inclined seismic waves

Abstract

The present invention relates to the field of earthquake engineering technology, and specifically discloses a design method for low-cycle repeated loading tests of pile foundations simulating the oblique incidence of seismic waves. First, a gravity compensation component and an angle compensator are used to ensure that the test results only reflect the effect of the obliquely incident seismic waves, eliminating the influence of non-seismic wave forces. Then, density anomaly factors and water content anomaly factors are obtained through the processing of soil data, and the pile foundation bearing capacity signal is calculated based on this. Based on the bearing capacity signal, the energy dissipation data and displacement data of the pile foundation are further obtained, and these data are comprehensively analyzed to calculate the comprehensive seismic performance score of the pile foundation. If the score is lower than the preset threshold, the test conditions are optimized by adjusting the obliquely incident seismic waves at different angles until the seismic performance of the pile foundation reaches above the predetermined standard. The present invention can improve the test accuracy and reliability and optimize the seismic performance of the pile foundation.

Description

Technical Field

[0001] The invention relates to the technical field of earthquake engineering, and in particular to a design method for a pile foundation low-cycle repeated load test simulating earthquake oblique wave incidence. Background Art

[0002] With the acceleration of urbanization, the construction of high-rise buildings and large-scale infrastructure is increasing, and earthquake disasters pose a serious threat to the safety of these structures. Especially in areas where earthquakes occur frequently, how to improve the seismic performance of buildings has become an important research topic. Among them, pile foundations are the foundation form of many buildings, and their seismic performance directly affects the safety of the entire structure.

[0003] Traditional pile foundation seismic performance evaluation methods mainly rely on field tests and empirical formulas, but these methods are often limited by site conditions and are difficult to fully and accurately reflect the behavior of pile foundations under actual earthquakes. In recent years, with the development of numerical simulation technology, more and more researchers have adopted numerical simulation methods to evaluate the seismic performance of pile foundations. However, most of the current numerical simulation methods have certain limitations.

[0004] In order to solve the above problems, the present invention effectively simulates the energy consumption capacity and recovery capacity of various components under the oblique incidence of seismic waves, and calculates the equivalent damping ratio of the structure; by accurately controlling the input angle of the oblique incidence seismic wave, combined with the precise measurement and processing of the simulated soil density data and water content data, the seismic performance of the pile foundation is evaluated and optimized, and the test conditions are adjusted to optimize the design of the pile foundation to make it have higher seismic resistance. Summary of the invention

[0005] The inclination angle of the test component is precisely controlled by using gravity compensation components and angle compensators to ensure that the simulated oblique incident seismic waves can truly reflect the actual earthquake situation. Secondly, the density data and water content data of the simulated soil are collected and processed to obtain the density anomaly factor and the water content anomaly factor, and then the bearing capacity signal of the pile foundation is calculated; the bearing capacity signal includes a high bearing capacity signal and a low bearing capacity signal, which reflect the strength of the pile foundation bearing capacity; based on the pile foundation bearing capacity signal, the pile foundation energy consumption data and displacement data are further obtained, and the comprehensive score of the seismic performance of the pile foundation is calculated by comprehensive analysis of these data; if the score reaches or exceeds the preset threshold, the pile foundation is considered to have strong seismic performance, otherwise it is weak; for poor performance (i.e., weak seismic signal), by adjusting the simulated oblique incident seismic waves at different angles, data collection is re-performed and the comprehensive score of seismic performance is calculated, in order to continuously optimize the test conditions and improve the seismic performance of the pile foundation to above the predetermined standard.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A design method for low-cycle repeated loading test of pile foundation simulating oblique incidence of seismic waves, comprising the following steps:

[0008] S1: Controlling the inclination angle of the component through the gravity compensation component and the angle compensator, and controlling the input of oblique incidence seismic waves;

[0009] S2: Obtaining simulated soil data, including density data and water content data, processing the density data and water content data to obtain a density anomaly factor and a water content anomaly factor, and processing the density anomaly factor and the water content anomaly factor to obtain a pile foundation bearing capacity signal;

[0010] Among them, the pile foundation bearing capacity signal includes a high pile foundation bearing capacity signal and a low pile foundation bearing capacity signal;

[0011] S3: Based on the pile foundation bearing capacity signal, obtaining pile foundation energy consumption data and displacement data, comprehensively analyzing the energy consumption data and displacement data to obtain a comprehensive seismic performance score, comparing the comprehensive seismic performance score with a preset threshold, and generating a seismic signal;

[0012] Among them, the seismic signal includes a strong seismic signal and a weak seismic signal;

[0013] S4: Based on the seismic signal, adjusting the oblique incidence seismic waves at different angles of simulation, re-performing data acquisition, calculating the comprehensive seismic performance score, and adjusting the simulated pile foundation to have high seismic performance.

[0014] As a further scheme of the present invention: Controlling the input mode of oblique incidence seismic waves: Applying a force in the horizontal direction through the gravity compensation component, and ensuring that the pile foundation maintains the original gravity action direction as the action direction changes during loading; By controlling the angle compensator, timely adjustment can be made when the angle of the pile body changes.

[0015] As a further scheme of the present invention: Obtaining the density data and water content data of the soil around the test component;

[0016] Processing the density data and water content data;

[0017] Obtaining a density anomaly factor PR and a water content anomaly factor PM;

[0018] Assigning a weight of w1 to the density anomaly factor PR and a weight of w2 to the water content anomaly factor PM;

[0019] Calculating to obtain the pile foundation bearing capacity score Q.

[0020] As a further scheme of the present invention: The process of obtaining the density anomaly factor PR is:

[0021] Obtaining the soil density Vi of each sub-region;

[0022] Among them, i represents i sub-regions, where i = 1, 2,......, n;

[0023] Integrate the soil density of all regions to obtain a soil density group;

[0024] Calculate the average soil density Vy of the soil density group through the mean calculation formula;

[0025] Calculate the soil density standard deviation C through the formula standard deviation calculation formula;

[0026] Process the soil density standard deviation C and the average soil density Vy, and combine the preset proportionality factors b1 and b2 to calculate the density anomaly factor PR through calculation;

[0027] Among them, b1 and b2 are preset proportionality factors, and both b1 and b2 are greater than 0.

[0028] As a further solution of the present invention:

[0029] The process of obtaining the water content anomaly factor PM is as follows:

[0030] Obtain the soil water content Di of each sub-region;

[0031] Among them, i represents i sub-regions, where i = 1, 2,......, n;

[0032] Integrate the soil water content of all regions to obtain a soil water content group;

[0033] Calculate the average soil water content Dy of the soil water content group through the mean calculation formula;

[0034] Calculate the soil water content standard deviation α of the soil water content group through the standard deviation calculation formula;

[0035] Process the average soil water content Dy and the soil water content standard deviation α, and combine the preset proportionality factors b3 and b4 to calculate the water content anomaly factor PM through calculation;

[0036] Among them, b3 and b4 are preset proportionality factors, and both b3 and b4 are greater than 0.

[0037] As a further solution of the present invention: Assign the weight of the density anomaly factor PR as w1, and assign the weight of the water content anomaly factor PM as w2;

[0038] Calculate the pile foundation bearing capacity score Q through calculation;

[0039] Compare the pile foundation bearing capacity score Q with the preset pile foundation bearing capacity threshold to generate a high pile foundation bearing capacity signal and a low pile foundation bearing capacity signal.

[0040] As a further solution of the present invention: obtain the energy dissipation data and displacement data of the pile foundation;

[0041] And process the energy dissipation data and displacement data to obtain the equivalent damping ratio η and the recovery coefficient R;

[0042] And compare them with the thresholds respectively;

[0043] Obtain high-dissipation energy signals, low-dissipation energy signals, high-recovery signals and low-recovery signals;

[0044] Process the equivalent damping ratio η and the recovery coefficient R to obtain the comprehensive score MS of the simulated seismic performance of the pile foundation, and compare it with the threshold of the comprehensive score of the seismic performance to generate a strong seismic signal and a weak seismic signal.

[0045] As a further solution of the present invention: the process of obtaining the equivalent damping ratio η:

[0046] Calculate to obtain the equivalent damping ratio η;

[0047] Among them, the equivalent damping ratio η represents the energy dissipation ability of the pile foundation;

[0048] The process of obtaining the dissipated energy Ed is:

[0049] Calculate to obtain the dissipated energy Ed;

[0050] The process of obtaining the recovery coefficient R:

[0051] Calculate to obtain the recovery coefficient R through the formula;

[0052] Among them, the recovery coefficient R represents the recovery ability of the pile foundation, δmax is the maximum displacement and δres is the residual displacement.

[0053] As a further solution of the present invention: the process of obtaining the comprehensive score MS of the seismic performance:

[0054] Assign the weight of the effective damping ratio η as w3 and the weight of the recovery coefficient R as w4;

[0055] Calculate to obtain the comprehensive score MS of the simulated seismic performance.

[0056] As a further solution of the present invention: based on the weak seismic signal, adjust the simulated oblique incident seismic waves at different angles, re-collect the soil data of each sub-region, calculate the pile foundation bearing capacity score Q, and on the basis of the high bearing capacity signal, calculate the comprehensive score MS of the simulated seismic performance, and adjust the comprehensive score MS of the simulated seismic performance to be greater than the preset comprehensive score of the seismic performance.

[0057] The beneficial effects of the present invention:

[0058] (1) The present invention ensures that the tilt angle of the test component can be precisely controlled by introducing a gravity compensation component and an angle compensator. This effectively eliminates the influence of non-seismic wave forces caused by the tilt of the test component, making the test results more reliable. At the same time, by real-time monitoring the tilt angle of the test component, it ensures that the direction of the obliquely incident seismic wave is accurate. This precise control mechanism helps to accurately simulate obliquely incident seismic waves at different angles, thereby improving the credibility and applicability of the test results. In addition, by collecting and processing the density data and water content data of the simulated soil, the present invention can obtain the density anomaly factor and the water content anomaly factor, and calculate the pile foundation bearing capacity signal based on this. This data-driven method for evaluating the bearing capacity of pile foundations can not only more objectively reflect the true condition of the pile foundation, but also provide a solid foundation for subsequent seismic performance evaluation;

[0059] (2) Based on the pile foundation bearing capacity signal, the present invention further obtains the pile foundation energy dissipation data and displacement data, and calculates the comprehensive seismic performance score of the pile foundation by comprehensively analyzing these data. This process not only considers the ability of the pile foundation to dissipate energy, but also considers its ability to return to its original state, comprehensively evaluating the seismic performance of the pile foundation. For cases with poor performance (i.e., weak seismic signals), the present invention adjusts the obliquely incident seismic waves at different angles, re-collects data, and calculates the comprehensive seismic performance score, thereby realizing the optimization of the seismic performance of the pile foundation. This method allows researchers and engineers to find the best pile foundation design scheme through continuous experimental iterations to ensure that it can perform well in the actual seismic environment. Description of the Drawings

[0060] The present invention will be further described below with reference to the accompanying drawings.

[0061] Figure 1 It is a schematic structural diagram of the specific steps of a method for designing a low-cycle repeated load test on a pile foundation for simulating the oblique incidence of seismic waves according to the present invention;

[0062] Figure 2 It is a schematic structural diagram of a method for generating and judging a pile foundation bearing capacity signal in a method for designing a low-cycle repeated load test on a pile foundation for simulating the oblique incidence of seismic waves according to the present invention;

[0063] Figure 3 It is a schematic structural diagram of a method for judging the comprehensive seismic performance score of a method for designing a low-cycle repeated load test on a pile foundation for simulating the oblique incidence of seismic waves according to the present invention. Detailed Embodiments

[0064] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0065] Please refer to Figure 1 As shown, the present invention is a design method for a low-cycle repeated load test of a pile foundation simulating the oblique incidence of seismic waves, including the following steps:

[0066] S1: Control the inclination angle of the component through the gravity compensation component and the angle compensator, and control the input of the oblique incident seismic wave;

[0067] S2: Obtain simulated soil data, including density data and water content data. By processing the density data and water content data, obtain the density anomaly factor and the water content anomaly factor. By processing the density anomaly factor and the water content anomaly factor, obtain the pile foundation bearing capacity signal;

[0068] Among them, the pile foundation bearing capacity signal includes a high pile foundation bearing capacity signal and a low pile foundation bearing capacity signal;

[0069] S3: Based on the pile foundation bearing capacity signal, obtain the pile foundation energy consumption data and displacement data, comprehensively analyze the energy consumption data and displacement data, obtain the comprehensive seismic performance score, compare the comprehensive seismic performance score with a preset threshold, and generate a seismic signal;

[0070] Among them, the seismic signal includes a strong seismic signal and a weak seismic signal;

[0071] S4: Based on the seismic signal, adjust the oblique incident seismic waves at different angles of simulation, re-collect data, calculate the comprehensive seismic performance score, and adjust the simulated pile foundation to have high seismic performance.

[0072] Embodiment 2

[0073] On the basis of Embodiment 1, design a gravity compensation component, which can offset the influence of the non-seismic wave force generated due to the inclination of the test component, and ensure that the test results only reflect the action of the oblique incident seismic wave; design an angle compensator, and precisely control the inclination angle of the test structure by adjusting the angle of the angle compensator to simulate oblique incident seismic waves at different angles; monitor the inclination angle of the test component in real time during the test to ensure that the direction of the oblique incident seismic wave is accurate.

[0074] Among them, a simulation environment is constituted by the gravity compensation component, the horizontal loading component, the vertical force transmission component and the geotechnical box;

[0075] It should be noted that when the component is tilted, the direction of the gravitational force no longer parallels the component. This will affect the accuracy of the results to a certain extent. A gravity compensation component will be added in the horizontal direction of the component, that is, a force will be applied in the horizontal direction. When loading, this component will maintain the original direction of the gravitational force as the acting direction changes. In addition, an angle compensator needs to be placed at the connection between the horizontal loading component and the test object. This is to facilitate adjusting the angle of the pile body at the beginning of the test. During the test, when the actuator changes the angle of the pile body, it can be adjusted in time.

[0076] Among them, the gravity compensation component: includes a spring system for providing a compensation force; includes an angle compensator for adjusting the inclination angle of the pile body at the beginning of the test and adjusting it in real time during the test to maintain the required inclination angle. The connection structure is: connect the pile and the gravity compensation device through a collar, and use nuts to tightly connect the collar and the pile to ensure a firm connection. Place fixed plugs at both ends of the gravity compensation device to prevent the turntable from rotating too much or driving the spring to apply force. The specific application process is as follows:

[0077] 1. Connect the test object and the gravity compensation device with bolts, and calculate the compensation force according to the required angle. The calculation formula is as follows:

[0078] F = G tanα1

[0079] In the formula, α1 is the inclination angle of the pile.

[0080] 2. Calculate the required elongation of the spring according to the calculated force. The calculation formula is as follows:

[0081] F = kΔ x

[0082]

[0083] In the formula, k is the spring stiffness coefficient, Δ x is the required elongation of the spring, G is the elastic modulus of the spring material, d is the wire diameter of the spring, N c is the effective total number (total number - 2), D m is the mean diameter (outer diameter D - wire diameter d).

[0084] 3. Calculate the elongation of the spring and the number of turns of the turntable rotation as

[0085]

[0086] In the formula, n is the number of turns of the turntable rotation, D is the diameter of the casing, and α is the thread inclination angle.

[0087] 4. Connect the angle compensator to the horizontal actuator, and at the same time observe whether the magnitude of the gravity compensator changes. If it changes, adjust it; also observe whether the angle changes. When both are adjusted to the appropriate angle and force, stop the adjustment.

[0088] Horizontal loading component: It consists of a reaction wall, positioning blocks, a horizontal actuator, and a force transfer hinge support. The horizontal actuator is connected to the reaction wall through the positioning blocks. The force transfer hinge support connects the vertical force transfer component.

[0089] Vertical force transfer component: It consists of bolts, nuts, and a vertical force transfer column. Among them, it is connected to the horizontal loading component and the test component through bolts and nuts respectively.

[0090] Geotechnical box: The geotechnical box is composed of acrylic transparent plates and stainless steel square tubes. The stainless steel square tubes form the geotechnical box skeleton by welding. Acrylic plates are nailed to the inside of the skeleton. The splicing gaps between the acrylic plates and the geotechnical box skeleton are made waterproof by applying glass glue. Four moving rollers are installed at the bottom of the geotechnical box. There are two directional wheels at the front side of the box body and two universal wheels at the rear side to facilitate the adjustment of the position of the geotechnical box. A motor is installed on the front side of the box body and connected to the front wheels; a steering wheel is installed on the rear side and connected to the rear wheels.

[0091] Embodiment 3

[0092] Please refer to Figure 2 As shown, on the basis of Embodiment 2, after controlling the input of the oblique incident seismic wave, the density data and water content data of the soil around the test component are obtained through simulation; the density data and water content data are processed to obtain the density anomaly factor PR and the water content anomaly factor PM; by processing the density anomaly factor and the water content anomaly factor, the pile foundation bearing capacity score Q is obtained and compared with the preset pile foundation bearing capacity score threshold; the pile foundation bearing capacity signal is obtained;

[0093] Among them, it includes a high bearing capacity signal and a low bearing capacity signal.

[0094] It should be noted that: the high or low of the bearing capacity signal reflects the strength of the pile foundation bearing capacity. The higher the pile foundation bearing capacity score, the stronger the pile foundation bearing capacity and the better the seismic performance.

[0095] Specific implementation steps:

[0096] Adjust the input of the oblique incident seismic wave, divide the simulated land into several sub-regions with the same area, and collect the density data and water content data of the soil in each sub-region respectively;

[0097] The process of obtaining the density anomaly factor PR is as follows:

[0098] Obtain the soil density Vi of each sub-region;

[0099] Among them, i represents i sub-regions, where i = 1, 2,......, n;

[0100] Integrate the soil density of all regions to obtain a soil density group;

[0101] Calculate the average soil density Vy of the soil density group through the mean calculation formula;

[0102] Through the formula Calculate the soil density standard deviation C;

[0103] Process the soil density standard deviation C and the average soil density Vy;

[0104] Through the formula Calculate the density anomaly factor PR;

[0105] Among them, b1 and b2 are preset proportionality factors, and both b1 and b2 are greater than 0;

[0106] The process of obtaining the water content anomaly factor PM is as follows:

[0107] Obtain the soil water content Di of each sub-region;

[0108] Integrate the soil water content of all regions to obtain a soil water content group;

[0109] Calculate the average soil water content Dy of the soil water content group through the mean calculation formula;

[0110] Calculate the soil water content standard deviation α of the soil water content group through the standard deviation calculation formula;

[0111] Process the average soil water content Dy and the soil water content standard deviation α;

[0112] Through the formula Calculate the water content anomaly factor PM;

[0113] Among them, b3 and b4 are preset proportionality factors, and both b3 and b4 are greater than 0;

[0114] Assign the weight of the density anomaly factor PR as w1, and assign the weight of the water content anomaly factor PM as w2;

[0115] Calculate the pile foundation bearing capacity score Q through the formula Q = PR * w1 + PM * w2;

[0116] Compare the pile foundation bearing capacity score Q with the preset pile foundation bearing capacity threshold;

[0117] If the pile foundation bearing capacity score Q is greater than or equal to the preset pile foundation bearing capacity threshold, it indicates that the pile foundation bearing capacity is strong, and a high pile foundation bearing capacity signal is generated;

[0118] If the pile foundation bearing capacity score Q is less than the preset pile foundation bearing capacity threshold, it indicates that the pile foundation bearing capacity is weak, and a low pile foundation bearing capacity signal is generated.

[0119] Embodiment 4

[0120] Please refer to Figure 3 As shown, based on the high pile foundation bearing capacity signal in Embodiment 3, a seismic simulation is carried out, and the pile foundation energy dissipation data and displacement data are obtained.

[0121] Among them, the energy dissipation data includes the energy Ed dissipated by the structure in one seismic cycle and the work done by the elastic restoring force within the same period, that is, the elastic energy Ee; the displacement data includes the maximum displacement δmax and the residual displacement δres.

[0122] Through the formula The equivalent damping ratio η is calculated.

[0123] Among them, the equivalent damping ratio η represents the ability of the pile foundation to dissipate energy.

[0124] The process of obtaining the dissipated energy Ed is as follows:

[0125] Through the formula The dissipated energy Ed is calculated.

[0126] Among them, Δu is the preset displacement amplitude, and F(u) represents the height at the displacement.

[0127] The equivalent damping ratio η is compared with the preset equivalent damping ratio threshold.

[0128] If the equivalent damping ratio η is greater than or equal to the preset equivalent damping ratio threshold, it indicates that the pile foundation has a strong ability to dissipate energy, absorbs and dissipates more energy during the earthquake, thereby reducing the seismic energy transmitted to the superstructure, and a high energy dissipation signal is generated.

[0129] If the equivalent damping ratio η is less than the preset equivalent damping ratio threshold, it indicates that the pile foundation has a weak ability to dissipate energy, absorbs and dissipates less energy during the earthquake, thereby increasing the seismic energy transmitted to the superstructure, and a low energy dissipation signal is generated.

[0130] Through the formula The recovery coefficient R is calculated.

[0131] Among them, the recovery coefficient R represents the recovery ability of the pile foundation.

[0132] The recovery coefficient R is compared with the preset recovery coefficient threshold.

[0133] If the recovery coefficient R is greater than or equal to the preset recovery coefficient threshold, it indicates that the pile foundation can recover well to the initial state or close to the initial state after experiencing the earthquake, and a high recovery signal is generated;

[0134] If the recovery coefficient R is less than the preset recovery coefficient threshold, it indicates that the pile foundation cannot recover well to the initial state or close to the initial state after experiencing the earthquake, and a low recovery signal is generated;

[0135] Process the equivalent damping ratio η and the recovery coefficient R to obtain the comprehensive score MS of the simulated seismic performance of the pile foundation;

[0136] Assign the weight of the equivalent damping ratio η as w3 and the weight of the recovery coefficient R as w4;

[0137] Calculate the comprehensive score MS of the simulated seismic performance through the formula MS = η * w3 + R * w4;

[0138] Compare the comprehensive score MS of the simulated seismic performance with the preset comprehensive score threshold of the simulated seismic performance;

[0139] If the comprehensive score MS of the simulated seismic performance is greater than or equal to the preset comprehensive score threshold of the simulated seismic performance, it indicates that the seismic performance of the pile foundation is strong, and a strong seismic signal is generated;

[0140] If the comprehensive score MS of the simulated seismic performance is less than the preset comprehensive score threshold of the simulated seismic performance, it indicates that the seismic performance of the pile foundation is weak, and a weak seismic signal is generated;

[0141] It should be noted that: the dissipated energy signal reflects the seismic performance of the pile foundation, which reflects the ability of the pile foundation to protect the structure from damage under earthquake action; a strong pile foundation recovery signal is another important indicator to measure its seismic performance, which reflects the ability of the pile foundation to maintain its original function under earthquake action.

[0142] Based on the weak seismic signal, adjust the simulated obliquely incident seismic waves at different angles, re-collect the soil data of each sub-region, calculate the pile foundation bearing capacity score Q, and on the basis of the high bearing capacity signal, calculate the comprehensive score MS of the simulated seismic performance, so that the comprehensive score MS of the simulated seismic performance is greater than the preset comprehensive score of the simulated seismic performance; thus realizing the high seismic performance of the simulated pile foundation.

[0143] Working principle of the present invention: First, by using a gravity compensation component and an angle compensator to precisely control the tilt angle of the test component, ensuring that the simulated obliquely incident seismic wave can truly reflect the actual seismic situation. This step is crucial for eliminating the influence of non-seismic wave forces to ensure that the test results only reflect the effect of the obliquely incident seismic wave. Secondly, by collecting the density data and water content data of the simulated soil mass, and processing them to obtain the density anomaly factor and water content anomaly factor, and then calculating the bearing capacity signal of the pile foundation. The bearing capacity signal includes a high bearing capacity signal and a low bearing capacity signal, which reflect the strength of the bearing capacity of the pile foundation. Then, based on the bearing capacity signal of the pile foundation, further obtain the energy consumption data and displacement data of the pile foundation, and calculate the comprehensive seismic performance score of the pile foundation through comprehensive analysis of these data. If this score reaches or exceeds the preset threshold, it is considered that the pile foundation has strong seismic performance, otherwise it is weak. Finally, for the case of poor performance (i.e., weak seismic signal), by adjusting the obliquely incident seismic waves at different angles of simulation, re-collect data and calculate the comprehensive seismic performance score, in order to continuously optimize the test conditions and improve the seismic performance of the pile foundation to above the predetermined standard.

[0144] The above has described in detail an embodiment of the present invention, but the content described is only the preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the present invention application should still fall within the scope covered by the patent of the present invention.

Claims

1. A design method for a pile foundation low-cycle repeated load test simulating earthquake oblique wave incidence, characterized in that: The following steps are involved: S1: The tilt angle of the component is controlled by the gravity compensation component and the angle compensator to control the input of oblique incident seismic waves; wherein the gravity compensation component includes a spring system for providing compensation force; the angle compensator is used to adjust the tilt angle of the pile body at the beginning of the test, and is adjusted in real time during the test to maintain the required tilt angle; the connection structure is: the pile is connected to the gravity compensation device through a collar, and the collar and the pile are tightly connected with a nut to ensure a firm connection, and fixed plugs are placed at both ends of the gravity compensation device to prevent the turntable from rotating too much or driving the spring to apply force; wherein the specific application process is as follows: Use bolts to connect the test object to the gravity compensation device, and calculate the compensation force according to the required angle. The calculation formula is as follows: ， In the formula, is the pile inclination angle; Based on the calculated force, calculate the required extension of the spring, the calculation formula is as follows: ， ， Where k is the spring stiffness coefficient, is the required elongation of the spring, G is the elastic modulus of the spring material, d is the spring wire diameter, For the effective total, is the median diameter; Calculate the spring extension and the number of turns of the turntable as: ， In the formula, n is the number of revolutions of the turntable, D is the diameter of the casing, is the thread inclination angle; Connect the angle compensator to the horizontal actuator, and observe whether the size of the gravity compensator changes. If so, adjust it. Also observe whether the angle changes. When the two are adjusted to the appropriate angle and force, stop adjusting. S2: Acquire simulated soil data, including density data and water content data, obtain density anomaly factor and water content anomaly factor by processing the density data and water content data, and obtain pile foundation bearing capacity signal by processing the density anomaly factor and water content anomaly factor; wherein the pile foundation bearing capacity signal includes a pile foundation bearing capacity high signal and a pile foundation bearing capacity low signal; The process of obtaining the density anomaly factor PR is as follows: Get the soil density Vi of each sub-area, where i represents the i-th sub-area; Integrate the soil densities of all regions to obtain a soil density group; The average soil density Vy of the soil density group is obtained by mean calculation; The standard deviation of soil density C is calculated by the formula standard deviation; The density anomaly factor PR is obtained by processing the soil density standard deviation C and the average soil density Vy; The process of obtaining the abnormal water content factor PM is as follows: Get the soil moisture content Di of each sub-area, where i represents the i-th sub-area; Integrate the soil moisture content of all regions to obtain a soil moisture group; The average soil moisture content Dy of the soil moisture content group is obtained by mean calculation; The standard deviation α of the soil moisture content of the soil moisture content group is obtained by calculating the standard deviation; The average soil moisture content Dy and the standard deviation of soil moisture content α are processed to obtain the moisture content anomaly factor PM; S3: Based on the pile foundation bearing capacity signal, the pile foundation energy consumption data and displacement data are obtained, the energy consumption data and displacement data are comprehensively analyzed to obtain a comprehensive score of seismic performance, the comprehensive score of seismic performance is compared with a preset threshold, and a seismic signal is generated; Among them, the earthquake resistance signal includes a strong earthquake resistance signal and a weak earthquake resistance signal; S4: Based on the seismic signal, adjust the simulated oblique incident seismic waves at different angles, re-collect data, calculate the comprehensive score of seismic performance, and adjust the simulated pile foundation to high seismic performance.

2. According to the design method of low-cycle repeated load test for pile foundation simulating oblique earthquake wave incidence as described in claim 1, the input mode of oblique incident earthquake wave is controlled: a force is applied in the horizontal direction through the gravity compensation component, and when loading, the pile foundation is ensured to maintain the original direction of gravity action as the direction of action changes; by controlling the angle compensator, the angle of the pile body is adjusted in time when it changes.

3. The design method for pile foundation low-cycle repeated load test simulating earthquake oblique wave incidence according to claim 1, characterized in that: Obtain density data and water content data of the soil around the test component; Process density data and water content data; Obtain the density anomaly factor PR and the water content anomaly factor PM; The weight of the density anomaly factor PR is assigned to w1, and the weight of the water content anomaly factor PM is assigned to w2; The pile foundation bearing capacity score Q is calculated.

4. A design method for pile foundation low-cycle repeated load test simulating earthquake oblique wave incidence according to claim 3, characterized in that: Compare the pile foundation bearing capacity score Q with a preset pile foundation bearing capacity threshold; If the pile foundation bearing capacity score Q is greater than or equal to the preset pile foundation bearing capacity threshold, it means that the pile foundation bearing capacity is strong, and a high pile foundation bearing capacity signal is generated; If the pile foundation bearing capacity score Q is less than the preset pile foundation bearing capacity threshold, it means that the pile foundation bearing capacity is weak, and a low pile foundation bearing capacity signal is generated.

5. The design method for pile foundation low-cycle repeated load test simulating earthquake oblique wave incidence according to claim 1, characterized in that: Obtain pile foundation energy consumption data and displacement data; The energy consumption data and displacement data are processed to obtain the equivalent damping ratio and the coefficient of restitution R; The equivalent damping ratio Compare with a preset equivalent damping ratio threshold to generate a high dissipation energy signal and a low dissipation energy signal; Compare the restoration coefficient R with a preset restoration coefficient threshold to generate a high restoration signal and a low restoration signal; The effective damping ratio The weight of is assigned to w3, and the weight of the recovery coefficient R is assigned to w4; The comprehensive score MS of simulated seismic performance is obtained through calculation.

6. A design method for pile foundation low-cycle repeated load test simulating earthquake oblique wave incidence according to claim 5, characterized in that: Equivalent damping ratio Acquisition process: The equivalent damping ratio is obtained by calculation ; Among them, the equivalent damping ratio It indicates the ability of pile foundation to dissipate energy; The process of obtaining the dissipated energy Ed is: The dissipated energy Ed is obtained by calculation; The process of obtaining the recovery coefficient R is as follows: The restitution coefficient R is calculated by the formula; Among them, the restitution coefficient R represents the restoring capacity of the pile foundation, δmax is the maximum displacement and δres is the residual displacement.

7. A design method for pile foundation low-cycle repeated load test simulating earthquake oblique wave incidence according to claim 6, characterized in that: The simulated comprehensive seismic performance score MS is compared with the comprehensive seismic performance score threshold to generate a strong seismic resistance signal and a weak seismic resistance signal.

8. The method for designing a pile foundation low-cycle repeated load test simulating earthquake oblique wave incidence according to claim 1, characterized in that: Based on the weak seismic signal, the simulated oblique incident seismic waves at different angles are adjusted, the soil data of each sub-area are re-collected, the pile foundation bearing capacity score Q is calculated, and based on the high bearing capacity signal, the simulated seismic performance comprehensive score MS is calculated, and the simulated seismic performance comprehensive score MS is adjusted to be greater than the preset seismic performance comprehensive score.

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