Simulation Test Method for Dynamic Response between Pile and Soil

Abstract

The present invention relates to the technical field of civil engineering, and particularly relates to a method for simulating the dynamic response between piles and soil, including: obtaining the soil parameters, pile body parameters, and construction parameters of the target engineering site; establishing a generalized model of the pile-soil dynamic system according to a preset similarity ratio, and respectively determining the soil parameters of the sandy soil layer, the pile body parameters of the simulated pile, the first dynamic loading parameters and the second dynamic loading parameters of the loading system; preparing a pile-soil system according to the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile, controlling the pile-soil system to perform vibrating pile driving and vibrating pile extraction based on the first dynamic loading parameters and the second dynamic loading parameters, monitoring the test data during the vibrating pile driving and vibrating pile extraction processes, and analyzing to obtain the simulation analysis results of the dynamic response between piles and soil. Thereby, the problems of cumbersome work, high cost, and difficulty in accurately depicting the research on the dynamic response law between piles and soil are solved, and the dynamic response law between piles and soil under different conditions can be simulated efficiently and accurately.

Description

Technical Field

[0001] This application relates to the technical field of civil engineering, and particularly relates to a method for simulating the dynamic response between piles and soil. Background Art

[0002] In recent years, with the gradual saturation of the development and utilization of shallow and middle-layer underground spaces in China, more and more urban underground spaces have begun to show a "high-density" development state with high building plot ratios and high coverage rates. When carrying out underground engineering construction in an environment with limited and intricate working spaces, it is extremely easy to cause problems such as road surface collapse, damage to existing buildings (structures) and underground pipelines, seriously threatening the lives and property of the people and the safety of national land space.

[0003] The construction technology of vibrating steel sheet pile driving and extracting has the characteristics of strong formation adaptability, small working space requirements, and convenient construction. It has currently been widely used in projects such as foundation pit support and cofferdams. The principle of the construction technology of vibrating steel sheet pile driving and extracting is to soften the soil around the pile through high-frequency vibration (25 - 65 Hz), so that the dense state between soil particles is destroyed, thereby reducing its cohesion and friction force, and enabling the pile to be smoothly inserted or extracted. However, unreasonable construction parameters (such as the magnitude of the exciting force, frequency, amplitude, etc.) will exacerbate the range or degree of soil damage, especially in strata with finer particles and stronger water permeability such as sand.

[0004] In related technologies, the main research results and existing deficiencies of the vibrating steel sheet pile driving and extracting technology are as follows: (1) Related technologies mainly focus on the drivability of piles, the pile-soil contact characteristics during the pile driving process, and the vertical and horizontal bearing capacities after the pile is inserted into the soil. However, for the equally crucial pile extraction process, there is almost no relevant research work, and there is a lack of sufficient theoretical basis to optimize the construction process and parameters. (2) The research in related technologies focuses on clay strata, and relatively few studies have been conducted on sand strata. There are significant differences between sand and clay in terms of particle size, shape, intergranular friction characteristics, etc., and sand has the characteristics of loose particles, strong water permeability, and strong friction, which affect the interaction mechanism between the pile and the soil. (3) The research objects in related technologies mainly focus on pipe piles, and relatively few studies have been conducted on steel sheet piles (U-shaped, H-shaped, Z-shaped cross-sections). There are significant differences between pipe piles and steel sheet piles in terms of structure, material, and the interaction mechanism with the soil, and the research results focusing on the pipe pile type cannot be directly applied to the steel sheet pile type.

[0005] In addition, the dynamic response problem of the pile-soil system in the vibrating pile driving and extraction construction is affected by the loading mode, pile type characteristics and the basic properties of the soil. Related technologies often rely on simplified mechanical models, which are difficult to accurately reflect the complex pile-soil interaction process and the dynamic mechanical behavior of the soil mass. When using numerical simulation methods, it is difficult to solve the problem of large deformation of the soil around the pile during the pile driving process, and problems of non-convergence are likely to occur in the calculation; when simulating pile extraction, it is also difficult to restore the deformation recovery process of the soil mass. At the same time, the soil around the pile is prone to liquefaction or softening under the action of high-frequency vibration, which also poses high requirements for the accuracy of the soil constitutive equation and the performance of the computer. When using on-site tests, due to the inhomogeneity of the rock and soil mass and the complex influencing factors during the test process, the discreteness of the test results is relatively high; at the same time, restricted by the construction site conditions, the comprehensiveness and accuracy of on-site monitoring data are also difficult to guarantee. In addition, although some laboratory tests have carried out relevant research, however, there is almost no research on the whole process of vibrating steel sheet pile driving and extraction and its influence on the soil around the pile, and the monitoring of important indicators such as the stress and deformation characteristics of the steel sheet pile and the characteristics of sand liquefaction failure is not comprehensive and accurate enough, which urgently needs to be solved. Summary of the Invention

[0006] The present application provides a simulation test method for the dynamic response between pile and soil to solve the problems that the work of studying the response law between pile and soil during the vibrating pile driving and extraction process is cumbersome, costly and difficult to accurately depict, and can efficiently and accurately simulate the dynamic response law between pile and soil under different types of soil layers, steel sheet piles with different cross-sectional forms and excitation parameters.

[0007] In the first aspect of the embodiments of the present application, a method for simulating the dynamic response between a pile and soil is provided. The method for simulating the dynamic response between a pile and soil is applied to a system for simulating the dynamic response between a pile and soil, and the system for simulating the dynamic response between a pile and soil includes: a loading system, a pile-soil system, a monitoring system, and a data acquisition system. Among them, the pile-soil system includes: a pile top fixture, a model pile, a model box, and a sandy soil layer. One end of the pile top fixture is connected to a conversion joint in the loading system, and the other end of the pile top fixture is connected to the model pile, so that the vibrating drill in the loading system is vertically connected to the model pile to form an integral body; the sandy soil layer is arranged in the model box; the monitoring system includes a first to a fourth accelerometer, a first to a fourth earth pressure cell, a first to a second pore pressure gauge, and a first to a fifth strain gauge group. The first accelerometer is arranged at the connection between the conversion joint and the pile top fixture, and the second to the fourth accelerometers are arranged on the surface of the sandy soil layer; the first earth pressure cell and the second earth pressure cell are arranged at a first depth position below the surface of the sandy soil layer, and the first earth pressure cell and the second earth pressure cell are located on both sides of the model pile and are symmetric; the third earth pressure cell and the fourth earth pressure cell are arranged at a second depth position below the surface of the sandy soil layer, and the third earth pressure cell and the fourth earth pressure cell are located on both sides of the model pile and are symmetric; the first pore pressure gauge and the second pore pressure gauge are located on both sides of the model pile and are symmetric; each strain gauge group includes three strain gauges, and the three strain gauges are located on the same horizontal line. The distance between the first strain gauge group and the bottom of the model pile is a first preset distance, the distance between the second strain gauge group and the fifth strain gauge group and the bottom of the model pile is a second preset distance, and the second strain gauge group is located inside the model pile, and the fifth strain gauge group is located outside the model pile. The distance between the third strain gauge group and the bottom of the model pile is a third preset distance, the distance between the fourth strain gauge group and the bottom of the model pile is a fourth preset distance, the fourth preset distance is greater than the third preset distance, the third preset distance is greater than the second preset distance, and the second preset distance is greater than the first preset distance. Among them, the method includes the following steps:

[0008] Obtain the soil parameters, pile body parameters, and construction parameters of the target engineering site;

[0009] Establish a generalized model of the pile-soil dynamic system according to a preset similarity ratio, and determine the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile according to the generalized model of the pile-soil dynamic system, the soil parameters, and the pile body parameters of the target engineering site, and determine the first dynamic loading parameter and the second dynamic loading parameter of the loading system according to the generalized model of the pile-soil dynamic system and the construction parameters;

[0010] Prepare the pile - soil system according to the soil parameters of the sandy soil stratum and the pile body parameters of the simulated pile. Control the pile - soil system to perform vibration pile sinking and vibration pile extraction through the loading system based on the first dynamic loading parameter and the second dynamic loading parameter. Use the monitoring system to monitor the test data at different times and different pile sinking depths during vibration pile sinking and vibration pile extraction, and analyze the test data through the data acquisition system to obtain the simulation analysis results of the pile - soil dynamic response.

[0011] Optionally, in some embodiments, the controlling the pile - soil system to perform vibration pile sinking and vibration pile extraction through the loading system based on the dynamic loading parameter includes:

[0012] Control the simulated pile of the pile - soil system to perform vibration pile sinking through the loading system based on the first dynamic loading parameter until the bottom of the simulated pile reaches the preset position, stop vibration pile sinking, and when the stop duration is greater than the preset duration, perform vibration pile extraction through the loading system based on the second dynamic loading parameter until the bottom of the simulated pile is pulled out from the sandy soil stratum, and then stop vibration pile extraction.

[0013] Optionally, in some embodiments, after stopping vibration pile extraction, it includes:

[0014] Generate a test end reminder instruction and give a reminder according to the test end reminder instruction.

[0015] Optionally, in some embodiments, before controlling the pile - soil system to perform vibration pile sinking and vibration pile extraction through the loading system based on the first dynamic loading parameter and the second dynamic loading parameter, it further includes:

[0016] Obtain the adjustment instructions for the first dynamic loading parameter and the second dynamic loading parameter;

[0017] Determine the adjusted first dynamic loading parameter and second dynamic loading parameter according to the adjustment instructions.

[0018] Optionally, in some embodiments, after using the monitoring system to monitor the test data at different times and different pile sinking depths during vibration pile sinking and vibration pile extraction, and analyzing the test data through the data acquisition system to obtain the simulation analysis results of the pile - soil dynamic response, it further includes:

[0019] Compare the simulation analysis results of the pile - soil dynamic response with the preset simulation analysis results to obtain an error analysis result, and generate a test parameter correction instruction according to the error analysis result;

[0020] According to the test parameter correction instruction, correct the soil parameters of the sandy soil layer, the pile body parameters of the simulated pile, the first dynamic loading parameters and the second dynamic loading parameters of the loading system to obtain the soil parameters of the new sandy soil layer, the pile body parameters of the simulated pile, the first dynamic loading parameters and the second dynamic loading of the loading system, and re - execute the step of preparing the pile - soil system according to the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile, and controlling the pile - soil system to perform vibration pile sinking and vibration pile pulling through the loading system based on the first dynamic loading parameters and the second dynamic loading parameters.

[0021] Optionally, in some embodiments, the test data includes at least one of vibration acceleration, earth pressure, pore water pressure, and pile body strain.

[0022] Optionally, in some embodiments, the soil parameters include at least one of density, compactness, and saturation.

[0023] Optionally, in some embodiments, the pile body parameters include at least one of material, cross - sectional dimension, length, density, and elastic modulus.

[0024] Optionally, in some embodiments, the construction parameters include at least one of exciting force, frequency, and amplitude.

[0025] Optionally, in some embodiments, the first dynamic loading parameters include at least one of vibration frequency, exciting force, direction, action time, sinking distance, and pile sinking rate;

[0026] The second dynamic loading parameters include at least one of vibration frequency, exciting force, direction, action time, rising distance, and pile pulling rate.

[0027] Therefore, the present application has the following beneficial effects:

[0028] (1) The present application can directly simulate the dynamic response law between the pile and the soil under different types of soil layers, different cross - sectional forms of steel sheet piles, and exciting parameters, solving the problems of large workload, high cost, and complex influencing factors in on - site tests.

[0029] (2) The present application can directly simulate the soil liquefaction and strength attenuation process during pile sinking under different exciting parameters, the stress and deformation characteristics of the pile body, and the soil deformation and strength recovery process during pile pulling, solving the problems of large difficulty in simulating the soil deformation of vibrating steel sheet piles during pile sinking and pulling in numerical simulation and poor reliability of the results.

[0030] (3) This application can efficiently and accurately record data such as vibration acceleration, pore water pressure, earth pressure, and pile body deformation during the sinking and pulling out of piles, solving the problems of incomplete and inaccurate acquisition of pile-soil dynamic response data during the vibration sinking and pulling out of steel sheet piles, and being unable to accurately reveal the dynamic response mechanism between the vibration sinking and pulling out of steel sheet piles and the soil body.

[0031] Additional aspects and advantages of this application will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of this application. Brief Description of the Drawings

[0032] The above-mentioned and / or additional aspects and advantages of this application will become apparent and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0033] Figure 1 is a schematic diagram of a pile-soil dynamic response simulation test system provided according to an embodiment of this application;

[0034] Figure 2 is a flowchart of a pile-soil dynamic response simulation test method provided according to an embodiment of this application;

[0035] Figure 3 is a schematic diagram of the implementation steps of a pile-soil dynamic response simulation test system provided according to an embodiment of this application;

[0036] Figure 4 is a schematic diagram of the particle size distribution curve of test sand provided according to an embodiment of this application;

[0037] Figure 5 is a schematic diagram of a pile-soil system provided according to an embodiment of this application;

[0038] Figure 6 is a schematic diagram of the cross-sectional dimensions of a model pile provided according to an embodiment of this application;

[0039] Figure 7 is a schematic diagram of a pile top fixture provided according to an embodiment of this application;

[0040] Figure 8 is a schematic diagram of the layout of soil sensors provided according to an embodiment of this application;

[0041] Figure 9 is a schematic diagram of the layout of pile body sensors provided according to an embodiment of this application. Detailed Embodiments

[0042] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application.

[0043] The pile-soil dynamic response simulation test method of the embodiments of the present application will be described below with reference to the accompanying drawings. In view of the problems in the above-mentioned background technology that the work of studying the response law between pile and soil during the vibration sinking and pulling process is cumbersome, costly and difficult to accurately describe, the present application provides a pile-soil dynamic response simulation test method. In this method, it includes: obtaining the soil parameters, pile body parameters and construction parameters of the target engineering site, establishing a generalized model of the pile-soil dynamic system according to a preset similarity ratio, and determining the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile according to the generalized model of the pile-soil dynamic system and the soil parameters and pile body parameters of the target engineering site respectively, and determining the first dynamic loading parameter and the second dynamic loading parameter of the loading system according to the generalized model of the pile-soil dynamic system and the construction parameters, preparing a pile-soil system according to the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile, controlling the pile-soil system to perform vibration pile sinking and vibration pile pulling through the loading system based on the first dynamic loading parameter and the second dynamic loading parameter, using the monitoring system to monitor the test data at different times and different pile sinking depths during the vibration pile sinking and vibration pile pulling processes, and analyzing the test data through the data acquisition system to obtain the pile-soil dynamic response simulation analysis result. Thereby, the problems that the work of studying the response law between pile and soil during the vibration sinking and pulling process is cumbersome, costly and difficult to accurately describe are solved, and the pile-soil dynamic response laws under different types of soil layers, different cross-section forms of steel sheet piles and excitation parameters can be simulated efficiently and accurately.

[0044] Before introducing the pile-soil dynamic response simulation test method of the embodiments of the present application, the pile-soil dynamic response simulation test system will be introduced first, as Figure 1 shown, the pile-soil dynamic response simulation test system includes: a loading system 100, a pile-soil system 200, a monitoring system 300 and a data acquisition system 400.

[0045] Among them, the loading system 100 includes: an exciter, a hydraulic system, a hoisting system, a support bench and a conversion joint.

[0046] The pile-soil system 200 includes: a pile top fixture, a model pile, a model box and a sandy soil layer. Among them, one end of the pile top fixture is connected to the conversion joint in the loading system, and the other end of the pile top fixture is connected to the model pile, so that the vibration drill in the loading system is vertically connected to the model pile to form a whole; the sandy soil layer is arranged in the model box.

[0047] The monitoring system 300 includes: first to fourth accelerometers, first to fourth earth pressure cells, first to second pore pressure gauges, and first to fifth strain gauge groups. Among them, the first accelerometer is arranged at the connection between the adapter and the pile top fixture, and the second to fourth accelerometers are arranged on the surface of the sandy soil layer; the first earth pressure cell and the second earth pressure cell are arranged at the first depth position below the surface of the sandy soil layer, and the first earth pressure cell and the second earth pressure cell are located on both sides of the model pile and are symmetric parts. The third earth pressure cell and the fourth earth pressure cell are arranged at the second depth position below the surface of the sandy soil layer, and the third earth pressure cell and the fourth earth pressure cell are located on both sides of the model pile and are symmetric parts; the first pore pressure gauge and the second pore pressure gauge are located on both sides of the model pile and are symmetric parts; each strain gauge group includes three strain gauges, and the three strain gauges are located on the same horizontal line. The distance between the first strain gauge group and the bottom of the model pile is the first preset distance, the distance between the second strain gauge group and the fifth strain gauge group and the bottom of the model pile is the second preset distance, and the second strain gauge group is located inside the model pile, and the fifth strain gauge group is located outside the model pile. The distance between the third strain gauge group and the bottom of the model pile is the third preset distance, and the distance between the fourth strain gauge group and the bottom of the model pile is the fourth preset distance. Among them, the fourth preset distance is greater than the third preset distance, the third preset distance is greater than the second preset distance, and the second preset distance is greater than the first preset distance.

[0048] Among them, the first preset distance, the second preset distance, the third preset distance, and the fourth preset distance can be preset by the user, can be obtained through a limited number of experiments, or can be obtained through a limited number of computer simulations, and no specific limitation is made here.

[0049] The data acquisition system 400 includes: a handheld dynamic signal test analyzer, a dynamic and static strain test acquisition instrument, and a signal test analysis system.

[0050] Specifically, Figure 2 This is a flowchart of the pile-soil dynamic response simulation test method provided by the embodiment of the present application.

[0051] As Figure 2 shown, the pile-soil dynamic response simulation test method includes the following steps:

[0052] In step S101, the soil parameters, pile body parameters, and construction parameters of the target engineering site are obtained.

[0053] Among them, the soil parameters include at least one of density, compactness, and saturation; the pile body parameters include at least one of material, cross-sectional dimension, length, density, and elastic modulus; the construction parameters include at least one of exciting force, frequency, and amplitude.

[0054] Specifically, the embodiments of the present application ascertain the geological conditions and physical and mechanical parameters of the rock and soil at the engineering site through engineering survey means or based on the construction site survey data; and clarify the construction parameters (exciting force, frequency, amplitude, etc.) and pile body parameters (pile body material, size, strength, pile type, etc.) of the vibration sinking-extraction piles according to the construction process plan.

[0055] In the actual implementation process, the embodiment of the present application can ensure that the simulation test is closer to the actual engineering conditions based on the acquired soil parameters, pile body parameters and construction parameters of the target engineering site, thereby improving the reliability and practicality of the test results.

[0056] In step S102, a generalized model of the pile-soil dynamic system is established according to a preset similarity ratio, and the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile are determined according to the generalized model of the pile-soil dynamic system and the soil parameters and pile body parameters of the target engineering site, and the first dynamic loading parameters and the second dynamic loading parameters of the loading system are determined according to the generalized model of the pile-soil dynamic system and the construction parameters.

[0057] Among them, the preset similarity ratio can be pre-set by the user, can be obtained through a limited number of experiments, or can be obtained through a limited number of computer simulations. No specific limitation is made here. The first dynamic loading parameter includes: at least one of vibration frequency, exciting force, direction, action time, sinking distance, and pile driving rate; the second dynamic loading parameter includes: at least one of vibration frequency, exciting force, direction, action time, sinking distance, and pile pulling rate.

[0058] Specifically, the embodiment of the present application is based on similarity theory, comprehensively considering factors such as the size of the test model, material type, loading method, and measurement point arrangement, to determine the similarity ratio between the test model and the prototype, that is, a preset similarity ratio, including: geometric similarity, material similarity, motion / dynamic similarity, and establish a generalized model of the pile-soil dynamic system.

[0059] Based on the similarity ratio between the generalized model of the pile-soil dynamic system and the preset one, the pile body parameters (material, cross-sectional size, length, density, elastic modulus, etc.) of the simulated pile, the soil parameters (density, compactness, saturation, etc.) of the sandy soil layer and the vibration hammer parameters (vibration frequency, amplitude, exciting force, etc.) of the loading system are determined. The first loading parameters of the vibration pile (vibration frequency f, exciting force F, direction D, action time t, sinking distance s, pile sinking rate, etc.) are determined according to the vibration hammer parameters. v 沉 ) and the second loading parameters of vibration pile extraction (vibration frequency f, exciting force F, direction D, action time t, rising distance s, pile extraction rate v 拔 ).

[0060] In step S103, a pile - soil system is prepared according to the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile. Based on the first dynamic loading parameter and the second dynamic loading parameter, the loading system is used to control the pile - soil system to perform vibration pile sinking and vibration pile pulling. The monitoring system is used to monitor the test data at different times and different pile sinking depths during the vibration pile sinking and vibration pile pulling processes, and the test data is analyzed through the data acquisition system to obtain the simulation analysis results of the pile - soil dynamic response.

[0061] Among them, the test data includes at least one of vibration acceleration, earth pressure, pore water pressure, and pile body strain.

[0062] Specifically, after obtaining test parameters such as the soil parameters of the sandy soil layer, the pile body parameters of the simulated pile, and the vibration hammer parameters of the loading system, a simulation test system for the dynamic response between the pile and the soil is established. According to the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile, a pile - soil system is prepared. After preparing the sandy soil layer and connecting the simulation test system for the dynamic response between the pile and the soil, based on the first dynamic loading parameter and the second dynamic loading parameter, the loading system is used to control the pile - soil system to perform vibration pile sinking and vibration pile pulling.

[0063] Furthermore, in some embodiments, controlling the pile - soil system to perform vibration pile sinking and vibration pile pulling based on the dynamic loading parameter includes: controlling the simulated pile of the pile - soil system to perform vibration pile sinking based on the first dynamic loading parameter until the bottom of the simulated pile reaches the preset position, stopping the vibration pile sinking, and when the stop duration is greater than the preset duration, performing vibration pile pulling based on the second dynamic loading parameter through the loading system until the bottom of the simulated pile is pulled out from the sandy soil layer, and then stopping the vibration pile pulling.

[0064] Among them, the preset position and the preset duration can be preset by the user, can be obtained through a limited number of experiments, or can be obtained through a limited number of computer simulations, and no specific limitation is made here. Preferably, in order to ensure that the soil disturbed by the pile sinking is fully consolidated, the preset duration is 48 hours.

[0065] Specifically, after the simulation test system for the dynamic response between the pile and the soil is prepared, the simulation and monitoring of the vibration pile sinking process are carried out. Specifically, the adapter and the support frame are adjusted to determine the position of the pile - soil system, and the loading parameters of the vibration pile sinking are set (vibration frequency f , exciting force F , direction D , action time t , sinking distance s , pile sinking rate v 沉 ), and the vibration pile sinking process is started. The vibration acceleration ( a ) and earth pressure (E ), pore water pressure ( P ), and pile body strain ( ε ). After the pile bottom is sunk into the preset position, the pile driving test ends.

[0066] The time interval between the vibratory pile extraction test and the vibratory pile driving test is not less than 48 hours to ensure that the soil disturbed by the pile to be sunk is fully consolidated. The dynamic loading parameter values of the vibratory pile extraction test and the vibratory pile driving test are kept consistent. Start the vibratory pile extraction process, and record the vibratory acceleration, earth pressure, pore water pressure, and pile body strain data at different times and pile tip depths during the vibratory pile extraction process. After the pile bottom is pulled out of the soil, the pile extraction test ends.

[0067] Optionally, in some embodiments, after stopping the vibratory pile extraction, it includes: generating a test end reminder instruction and giving a reminder according to the test end reminder instruction.

[0068] It can be understood that the test end reminder instruction can enable relevant personnel to timely understand the test progress and reasonably arrange subsequent work, such as equipment disassembly, data sorting and analysis, etc., avoid wasting time waiting for the test to end, and improve the test efficiency.

[0069] In the actual execution process, the embodiments of the present application can give the test end reminder instruction in ways such as visual reminder, auditory reminder, and information push. For example, an indicator light is set on the equipment or console. When the test end reminder instruction is generated, the indicator light lights up or flashes to attract the attention of relevant personnel. A red indicator light is used to indicate the end of the test, and a green indicator light is used to indicate that the test is proceeding normally.

[0070] Optionally, in some embodiments, before controlling the pile - soil system to perform vibratory pile driving and vibratory pile extraction through the loading system based on the first dynamic loading parameter and the second dynamic loading parameter, it further includes: obtaining adjustment instructions for the first dynamic loading parameter and the second dynamic loading parameter; and determining the adjusted first dynamic loading parameter and the second dynamic loading parameter according to the adjustment instructions.

[0071] It can be understood that the embodiments of the present application can also depict the soil liquefaction and strength attenuation process, the pile body stress and deformation characteristics during pile driving under different excitation parameters, and the soil deformation and strength recovery process during pile extraction by adjusting the first dynamic loading parameter and the second dynamic loading parameter, solving the problems of large modeling difficulty and unreliable results in numerical simulation. In addition, during the test process, if it is found that the equipment is operating abnormally or there are potential safety hazards, the dynamic loading parameters can also be adjusted to reduce the operating load of the equipment and prevent equipment damage.

[0072] In the actual implementation process, when it is necessary to adjust the first dynamic loading parameter and the second dynamic loading parameter, relevant personnel or the control system can generate an adjustment instruction, and adjust the first dynamic loading parameter and the second dynamic loading parameter according to the adjustment instruction, so as to measure data such as the vibration acceleration, pore water pressure, earth pressure, and pile body deformation of the pile-soil system under different dynamic loading parameters.

[0073] Optionally, in some embodiments, after using the monitoring system to monitor the test data at different times and different pile sinking depths during the vibration pile driving and vibration pile extraction processes, and analyzing the test data through the data acquisition system to obtain the pile-soil dynamic response simulation analysis result, it further includes: comparing the pile-soil dynamic response simulation analysis result with the preset simulation analysis result to obtain an error analysis result, and generating a test parameter correction instruction according to the error analysis result; according to the test parameter correction instruction, correcting the soil parameters of the sandy soil layer, the pile body parameters of the simulated pile, and the first dynamic loading parameter and the second dynamic loading parameter of the loading system to obtain the new soil parameters of the sandy soil layer, the pile body parameters of the simulated pile, and the first dynamic loading parameter and the second dynamic loading of the loading system, and re-executing the steps of preparing the pile-soil system according to the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile, and controlling the pile-soil system to perform vibration pile driving and vibration pile extraction based on the first dynamic loading parameter and the second dynamic loading parameter.

[0074] It can be understood that after generating the pile-soil dynamic response simulation analysis result, by comparing the pile-soil dynamic response simulation analysis result with the preset simulation analysis result, the deviation existing in the model can be found, and then the soil parameters, pile body parameters, and dynamic loading parameters can be corrected to make the model closer to the actual engineering situation, and the corrected parameters can improve the prediction ability of the model for the pile-soil system under different working conditions, providing a more accurate basis for subsequent construction.

[0075] Specifically, the embodiment of the present application can preset the simulation analysis result of the pile-soil system during the vibration pile driving and vibration pile extraction processes according to engineering experience, relevant specifications, or test data of previous similar projects, such as the expected range of pile top displacement, the expected distribution of pile body stress, etc., compare the pile-soil dynamic response simulation analysis result with the preset simulation analysis result, calculate the error magnitude to obtain the error analysis result, analyze the main reasons for the error according to the error comparison result, and determine the parameters to be corrected and their correction directions according to the error reasons, generate a correction instruction, and re-execute the test according to the correction. Specifically, at least one of the soil parameters, pile body parameters, first dynamic loading parameter, and second dynamic loading parameter is corrected, and according to the corrected parameters, a new pile-soil system is prepared, and the pile-soil system is controlled to perform vibration pile driving and vibration pile extraction to obtain a new simulation result, and a new error analysis result is generated until the error analysis result is within an acceptable range.

[0076] To enable those skilled in the relevant art to further understand the pile - soil dynamic response simulation test method implemented in this application, the following will be described in detail with specific embodiments.

[0077] As Figure 3 shown, Figure 3 It is a schematic diagram of the implementation steps of the pile - soil dynamic response simulation test method proposed according to the embodiments of this application.

[0078] Taking an open - cut foundation pit project of an urban underground utility tunnel as an example in the embodiments of this application, due to the narrow construction space and complex surrounding environment, L - type steel sheet piles are selected as the foundation pit support structure.

[0079] Step (a): According to the existing engineering site investigation data and combined with engineering geological exploration, it is found that there is a 12 - m - thick fine sand layer distributed within the construction influence range. The soil layer is saturated with water and has a relatively high density. The physical and mechanical parameters of the fine sand layer are obtained through borehole data and laboratory tests, as shown in Table 1. Table 1 is the table of physical and mechanical parameters of the soil.

[0080] Table 1

[0081]

[0082] On - site, a high - frequency hydraulic vibratory hammer is used to complete the construction of the steel sheet piles. As shown in Table 2, Table 2 is the technical parameter table of the high - frequency hydraulic vibratory hammer, including the main technical parameters of the steel sheet pile construction.

[0083] Table 2

[0084]

[0085] The model of the L - type steel sheet pile is SP - IV, and its cross - section is U - shaped. The dimensions are width 400 mm, height 170 mm, thickness 16.0 mm, and the cross - sectional area is 96.99 cm2.

[0086] Taking into comprehensive consideration factors such as the size of the indoor test site, equipment performance, material parameters, and layout of monitoring points, it is determined to conduct a model test under the condition of 1 g normal gravity. The similarity ratio between the generalized model of the pile - soil dynamic system and the prototype is shown in Table 3. Table 3 is the similarity ratio table between the generalized model of the pile - soil dynamic system and the prototype.

[0087] Table 3

[0088]

[0089] It should be noted that when the ratio of the foundation width of the generalized model of the pile - soil dynamic system to the average particle size of the foundation material is greater than 233, the influence of the particle size effect on the test results is less than 1% and can be basically ignored.

[0090] Step (b), based on the generalized model of the pile-soil dynamic system, determine the pile body parameters (material, cross-sectional dimensions, length, density, elastic modulus, etc.), soil parameters (density, compactness, saturation, etc.), and vibratory hammer parameters (vibration frequency, exciting force, etc.), as shown in Table 3. The magnitudes of the amplitude and exciting force are related to the dynamic loading test equipment. For this test equipment, when the vibration frequency is 45 Hz, the amplitude is approximately 2 mm and the exciting force is approximately 0.5 kN. The sand is taken from the construction site of the vibrating steel sheet pile, and its particle size distribution is as Figure 4 ; To obtain a model pile that meets the design similarity ratio, aluminum-magnesium alloy is selected as the pile body material. In the model test, the processes of vibration, pile driving, and pile extraction are realized through the loading system;

[0091] Step (c), according to the determined test materials and parameters, build the dynamic response simulation test system 10 for the pile-soil interface. The dynamic response simulation test system 10 for the pile-soil interface consists of four subsystems: a loading system 100, a pile-soil system 200, a monitoring system 300, and a data acquisition system 400, as Figure 1 . The loading system 100 includes an exciter, a hydraulic system, a hoisting system, a support frame, and a conversion joint; the pile-soil system 200 includes a model pile, a model box, a soil layer, and a pile top fixture; the monitoring system 300 includes vibration acceleration sensors, earth pressure cells, pore water pressure sensors, and strain gauges; the data acquisition system 400 includes a dynamic signal test analyzer and a dynamic and static strain test acquisition instrument; the specific parameters of each subsystem are as follows:

[0092] (1) Loading system 100. A hydraulically driven vibrating drill is used, which can provide a vertical (axial) exciting force with a maximum frequency of 150 Hz; the vibrating drill uses the self-weight of the model pile and the static pressure / tension applied to the top of the pile to realize the pile driving and pile extraction processes; the vibrating drill and the model pile are connected as a whole through a conversion joint;

[0093] (2) Pile-soil system 200. The model foundation is prepared in a square plexiglass model box with dimensions of 1 m × 1 m × 1 m (in the X, Y, and Z directions), as Figure 5 . The internal joints of the model box are sealed, and a steel frame is added outside for fixation to meet the requirements of the test strength. The distance between the pile axis and the model box wall exceeds 20 times the effective pile diameter, and the boundary effect can be ignored; the model foundation is prepared by the diluvial method. The model foundation is prepared in layers (5 layers of 1 m and 1 layer of 0.2 m) to control the relative density (Dr) of the model foundation. First, the model box is filled with pure water, and then the known weight of each layer of sand is poured into the model box and tamped. In the case of Dr = 60%, the mass of the sand used for preparing each layer is approximately 330 kg.

[0094] The cross-section of the model pile is 100 mm wide, 43 mm high, 4 mm thick, and the total length is 50 cm, as Figure 6 shown.

[0095] The pile top fixture is welded by a flange plate and a micro bench vice, and is dimensionally adapted to the adapter, as shown in Figure 7 . The outer diameter of the flange plate is 160 mm, the inner diameter is 18 mm, the thickness is 15 mm, and the center distance of the screw holes is 125 mm. The flange plate has dimensions and hole positions matching those of the drill pipe joint. The jaw width of the micro bench vice is 60 mm, and the maximum clamping thickness is 30 mm (adjustable). The micro bench vice is welded to the flange plate and is on the same axis. The audio-frequency vibration drill is vertically connected to the model pile through the pile top fixture to form an integral whole;

[0096] (3) Monitoring system 300. Vibration acceleration sensors (marked as M1 - M4) are respectively arranged at the connection between the adapter and the pile top fixture and on the surface of the sandy soil layer near the model box wall. During the preparation process of the sandy soil layer, the sensors are arranged when the soil layer is laid to the corresponding depth, as shown in Figure 8 . Four earth pressure cells (marked as E1 - E4) are arranged. They are divided into two groups longitudinally, located on both sides of the model pile, and are symmetrically distributed. The burial depths are 10 cm and 30 cm below the surface of the foundation soil respectively, and the radial distances from the model pile are both 10*δ (δ is the thickness of the model pile), 4 cm. Two pore pressure sensors (marked as P1 and P2) are buried. They are arranged in a group longitudinally, located on both sides of the model pile, and are symmetrically distributed. The burial depth is 20 cm, and the radial distance from the model pile is 10*δ, 4 cm.

[0097] Strain gauges (marked as S1 - S15) are evenly pasted on the web and flange of the model pile and are arranged in a symmetric manner, as shown in Figure 9 . The 15 strain gauges are divided into five groups, and each group of strain gauges is on the same horizontal line. The first group is S1 - S3, the second group is S4 - S6, the third group is S7 - S9, the fourth group is S10 - S12. The distances between each group of strain gauges and the bottom of the pile are 2 cm, 6 cm, 14 cm, and 30 cm respectively. The fifth group is S13 - S15, the distance from the bottom of the pile is 14 cm, and it is symmetrically arranged with the second group on both sides of the model pile. Sealant is applied around the strain gauges for waterproof treatment.

[0098] (4) Acquisition system 400. The signal test and analysis system software is used for the analysis and processing of acceleration signals. The earth pressure, pore water pressure, and strain signals are collected by a dynamic and static strain test and acquisition instrument. The dynamic and static strain test and analysis system software is used for the analysis and processing of the stress and strain signals generated during the model test.

[0099] Step (d): After the soil mass has been left static for 48 hours, connect the pile-soil dynamic response simulation test system, and set the vibration frequency f, exciting force F, inclination angle θ, action time t, sinking distance s, and pile driving rate v for vibratory pile driving as: 45 Hz, 0.5 kN, 270°, 20 s, 40 cm, and 2 cm / s respectively, and start the vibratory pile driving process. Record the vibration acceleration (a), earth pressure (E), pore water pressure (P), and pile body strain (ε) data at different times (0 - 20 s) and pile sinking depths (0 - 40 cm) during the vibratory pile driving process. After the pile bottom has sunk 40 cm into the sand layer, the pile driving test ends.

[0100] Step (e): 48 hours after the vibratory pile driving test ends, start the vibratory pile extraction test. The vibration frequency f, exciting force F, inclination angle θ, action time t, sinking distance s, and pile driving rate v for vibratory pile extraction are: 45 Hz, 0.5 kN, 90°, 20 s, 40 cm, and 2 cm / s respectively. Record the vibration acceleration (a), earth pressure (E), pore water pressure (P), and pile body strain (ε) data at different times (0 - 20 s) and pile tip depths (0 - 40 cm) during the vibratory pile extraction process. When the pile tip depth is 0 cm, the test ends.

[0101] Thus, in the embodiment of the present application, by adjusting the sheet pile type, soil type and its parameters, exciting parameters, etc. in the pile-soil dynamic response simulation test system, the dynamic response law between the pile and the soil under various working conditions can be simulated, solving problems such as the cumbersome process and difficult collection of test data in on-site tests; moreover, in the embodiment of the present application, based on the data such as vibration acceleration, pore water pressure, earth pressure, and pile body deformation measured by the monitoring system, the soil liquefaction and strength attenuation process, the pile body stress and deformation characteristics during pile driving under different exciting parameters, and the soil deformation and strength recovery process during pile extraction can be characterized, solving the problems of large modeling difficulty and unreliable results in numerical simulation; in addition, the embodiment of the present application fills the technical gap in the related art that the response law and action mechanism between the pile and the soil during the vibration pile driving and extraction process cannot be accurately simulated and revealed, providing a reliable test system and method for carrying out the full-process simulation and monitoring of the dynamic response between the pile and the soil in the indoor site.

[0102] According to the pile-soil dynamic response simulation test method proposed by the embodiments of the present application, by obtaining the soil parameters, pile body parameters and construction parameters of the target engineering site, establishing a generalized model of the pile-soil dynamic system according to the preset similarity ratio, and respectively determining the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile according to the generalized model of the pile-soil dynamic system and the soil parameters and pile body parameters of the target engineering site, and determining the first dynamic loading parameters and the second dynamic loading parameters of the loading system according to the generalized model of the pile-soil dynamic system and the construction parameters, and preparing a pile-soil system according to the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile, controlling the pile-soil system to perform vibration pile driving and vibration pile extraction through the loading system based on the first dynamic loading parameters and the second dynamic loading parameters, using the monitoring system to monitor the test data at different times and different pile driving depths during the vibration pile driving and vibration pile extraction processes, and analyzing the test data through the data acquisition system to obtain the pile-soil dynamic response simulation analysis results. Thus, the problems of cumbersome work, high cost and difficulty in accurately depicting the response law between the pile and the soil during the vibration pile driving and extraction process are solved, and the pile-soil dynamic response law under different types of soil layers, different cross-section forms of steel sheet piles and excitation parameters can be simulated efficiently and accurately.

[0103] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0104] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0105] Any process or method description depicted in the flowchart or otherwise described herein may be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a customized logical function or process. The scope of the preferred embodiments of the present application includes additional implementations, where the functions may be executed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed. This should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0106] It should be understood that the various parts of the present application may be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, the N steps or methods may be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art may be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays, field-programmable gate arrays, and the like.

[0107] Those of ordinary skill in the art can understand that all or part of the steps carried out in the method of the above embodiments can be completed by instructing relevant hardware through a program. The program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0108] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A pile-soil dynamic response simulation test method, characterized in that: The pile-soil dynamic response simulation test method is applied to a pile-soil dynamic response simulation test system, which includes: a loading system, a pile-soil system, a monitoring system and a data acquisition system, wherein the pile-soil system includes: a pile top fixture, a model pile, a model box and a sandy soil layer, wherein one end of the pile top fixture is connected to the conversion joint in the loading system, and the other end of the pile top fixture is connected to the model pile, so that the vibration drill in the loading system is vertically connected to the model pile to form a whole; the sandy soil layer is arranged in the model box; the monitoring system includes first to fourth accelerometers, first to fourth earth pressure boxes, first to second borehole pressure gauges and first to fifth strain gauge groups, the first accelerometer is arranged at the connection between the conversion joint and the pile top fixture, and the second to fourth accelerometers are arranged on the surface of the sandy soil layer; the first earth pressure box and the second earth pressure box are arranged at a first depth position below the surface of the sandy soil layer, and the first earth pressure box and the second earth pressure box are located on both sides of the model pile, and are symmetrical parts, the third earth pressure box and the fourth earth pressure box are arranged at the second depth position below the surface of the sand layer, and the third earth pressure box and the fourth earth pressure box are located on both sides of the model pile and are symmetrical parts; the first hole pressure gauge and the second hole pressure gauge are located on both sides of the model pile and are symmetrical parts; each group of strain gauges includes three strain gauges, and the three strain gauges are located on the same horizontal line, the distance between the first strain gauge group and the bottom of the model pile is a first preset distance, the distance between the second strain gauge group and the fifth strain gauge group and the bottom of the model pile is a second preset distance, and the second strain gauge group is located on the inner side of the model pile, the fifth strain gauge group is located on the outer side of the model pile, the distance between the third strain gauge group and the bottom of the model pile is a third preset distance, the distance between the fourth strain gauge group and the bottom of the model pile is a fourth preset distance, the fourth preset distance is greater than the third preset distance, the third preset distance is greater than the second preset distance, and the second preset distance is greater than the first preset distance, wherein the method comprises the following steps: Obtain soil parameters, pile parameters and construction parameters of the target project site; A generalized model of a pile-soil dynamic system is established according to a preset similarity ratio, and soil parameters of the sandy soil layer and pile body parameters of the simulated pile are determined according to the generalized model of the pile-soil dynamic system and soil parameters and pile body parameters of the target engineering site, and a first dynamic loading parameter and a second dynamic loading parameter of the loading system are determined according to the generalized model of the pile-soil dynamic system and construction parameters; The pile-soil system is prepared according to the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile, and the pile-soil system is controlled by the loading system to perform vibration pile sinking and vibration pile pulling based on the first dynamic loading parameter and the second dynamic loading parameter. The monitoring system is used to monitor the test data at different times and different pile sinking depths during the vibration pile sinking and vibration pile pulling process, and the test data is analyzed by the data acquisition system to obtain the simulation analysis results of the pile-soil dynamic response, wherein: The method of controlling the pile-soil system to perform vibration pile sinking and vibration pile extraction through the loading system based on the dynamic loading parameters includes: Based on the first dynamic loading parameter, the simulated pile of the pile-soil system is controlled by the loading system to perform vibration pile sinking until the bottom of the simulated pile reaches a preset position, and the vibration pile sinking is stopped. When the stopping time is longer than the preset time, the loading system is controlled to perform vibration pile pulling based on the second dynamic loading parameter until the bottom of the simulated pile is pulled out of the sandy soil layer, and the vibration pile pulling is stopped.

2. The method according to claim 1, characterized in that: After stopping the vibration pile extraction, including: Generate a test end reminder instruction, and issue a reminder according to the test end reminder instruction.

3. The method according to claim 1, characterized in that Before controlling the pile-soil system to perform vibration pile sinking and vibration pile extraction through the loading system based on the first dynamic loading parameter and the second dynamic loading parameter, the method further includes: Obtaining adjustment instructions for the first power loading parameter and the second power loading parameter; According to the adjustment instruction, the adjusted first power loading parameter and the second power loading parameter are determined.

4. The method according to claim 1, characterized in that: After using the monitoring system to monitor the test data at different times and different pile sinking depths during the vibration pile sinking and vibration pile pulling process, and analyzing the test data through the data acquisition system to obtain the pile-soil dynamic response simulation analysis results, the method further includes: Comparing the pile-soil dynamic response simulation analysis result with a preset simulation analysis result to obtain an error analysis result, and generating a test parameter correction instruction according to the error analysis result; According to the test parameter correction instruction, the soil parameters of the sandy soil layer, the pile body parameters of the simulated pile, and the first dynamic loading parameters and the second dynamic loading parameters of the loading system are corrected to obtain new soil parameters of the sandy soil layer, the pile body parameters of the simulated pile, and the first dynamic loading parameters and the second dynamic loading of the loading system, and the steps of preparing the pile-soil system according to the soil parameters of the sandy soil layer and the pile body parameters of the simulated pile, and controlling the pile-soil system to perform vibration pile sinking and vibration pile pulling through the loading system based on the first dynamic loading parameters and the second dynamic loading parameters are re-executed.

5. The method according to claim 1, characterized in that The test data includes at least one of vibration acceleration, soil pressure, pore water pressure and pile body strain.

6. The method according to claim 1, characterized in that The soil parameters include: at least one of density, compactness and saturation.

7. The method according to claim 1, characterized in that The pile body parameters include: at least one of material, cross-sectional size, length, density, and elastic modulus.

8. The method according to claim 1, characterized in that The construction parameters include: at least one of exciting force, frequency, and amplitude.

9. The method according to claim 1, characterized in that: The first dynamic loading parameter includes: at least one of vibration frequency, exciting force, direction, action time, sinking distance, and pile sinking rate; The second dynamic loading parameter includes at least one of vibration frequency, exciting force, direction, action time, rising distance, and pile pulling rate.

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