A method and software system for analyzing response of pile groups under complex load conditions

Abstract

The application discloses a group pile response analysis method and software system under complex load conditions, which mainly analyzes the following two conditions: 1, only allowing the pile head to move horizontally, and the load acting on the pile head of each single pile in the group pile is known, and the group pile response is evaluated according to the following steps; 2, only allowing the pile head to move horizontally, the displacement of the pile head of each single pile is equal, but only the total load is known. The software system comprises a software main program interface, a calculation parameter input subroutine interface, a pile body response analysis subroutine interface and a calculation result output subroutine interface.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geotechnical engineering, and particularly relates to a group pile response analysis method and software system under complex load conditions. BACKGROUND

[0002] With group pile foundations being more and more widely used to bear active loads transmitted from buildings, or resist passive loads of soil in typical civil engineering such as slope engineering and foundation pit engineering, the response analysis of group pile foundations under the above loads alone or in combination is a key in the design of group pile foundations.

[0003] When the group pile spacing is close and the load is large, the group pile response analysis needs to include two aspects: 1. The stress superposition between group piles weakens the pile-soil interaction relationship (group pile effect); 2. When the load is large, it is necessary to consider the nonlinear pile-soil interaction relationship. In the existing group pile response analysis method, the above two influences are considered separately: 1. For active group piles subjected to only pile head load, the pile-soil interaction relationship is simplified as elastic, and only the influence of stress superposition between group piles is considered; 2. For group piles subjected to passive soil displacement in slope engineering, only the influence of nonlinear pile-soil interaction is considered.

[0004] For group pile foundations with close pile spacing, large pile head load (strong stress superposition between group piles), and simultaneously subjected to non-negligible passive soil displacement, it is necessary to analyze the combined effect of the above two influences. SUMMARY

[0005] In view of the above technical problems, the inventors have developed a group pile response analysis method and software system under complex load conditions based on their rich experience in the field of geotechnical engineering.

[0006] To achieve the above invention purpose, the present application adopts the following technical scheme: a group pile response analysis method under complex load conditions, comprising: a pile head translation occurs, and the load acting on each single pile head in the group pile is known, the group pile response is analyzed according to the following steps:

[0007] S1: based on the nonlinear foundation beam model theory, combining the central difference method to carry out finite difference on the deflection differential equation of the pile, to solve the single pile pile body response under complex load considering the nonlinear interaction of pile and soil;

[0008] S2: based on the elastic theory method, combining the finite element method, to solve the elastic pile body response of single pile and group pile under complex load considering the continuity of soil;

[0009] S3: Based on the result of S2, the elastic additional pile head displacement of pile group is solved, and the pile head displacement of pile group which can consider the nonlinear interaction between pile and soil and the pile group effect is obtained by adding the nonlinear response of each single pile;

[0010] S4: Based on the nonlinear foundation beam model theory, the Y multiplier is used to adjust the interaction curve between single pile and soil, so that the pile head displacement of single pile is equal to the pile head displacement of pile group obtained in S3, and the Y multiplier represents the pile group effect at this time.

[0011] When the pile head translation occurs, the pile head displacement of each single pile is equal, but only the total load is known. The pile group response is analyzed according to the following steps:

[0012] S1: Based on the nonlinear foundation beam model theory, the finite difference of the pile deflection differential equation is carried out by combining the central difference method, and the single pile response under complex load is analyzed by considering the nonlinear interaction between pile and soil.

[0013] S2: Based on the elastic theory method, the elastic pile body response of single pile and pile group considering the continuity of soil under complex load is solved by combining the finite element method.

[0014] S3: Based on the result of S2, the elastic additional pile head displacement of pile group is solved, and the pile head displacement of pile group which can consider the nonlinear interaction between pile and soil and the pile group effect is obtained by adding the nonlinear response of each single pile;

[0015] S4: Based on the conditions that the pile head displacement of each single pile is equal and the sum of the pile head load of each single pile is known, the pile head load of each single pile is redistributed until the pile head distribution load and the pile head displacement of pile group which meet the above two conditions are obtained.

[0016] S5: Based on the nonlinear foundation beam model theory, the Y multiplier is used to adjust the interaction curve between single pile and soil, so that the pile head displacement of single pile is equal to the pile head displacement of pile group obtained in S4, and the Y multiplier represents the pile group effect at this time.

[0017] Further, the complex load condition refers to the loading condition of pile group which is subjected to the pile head load and the passive soil load distributed along the pile body at the same time.

[0018] The application further provides a group pile response software system under complex load conditions, comprising: a software main program interface, which comprises a software authorization validity verification module; a calculation parameter input subprogram interface, which comprises a group pile configuration parameter input module, a soil layer parameter input module, a free field soil body displacement parameter input module and a load input module; a pile body response analysis subprogram interface, which comprises a single pile nonlinear response analysis module, a single pile elastic analysis module, a group pile elastic analysis module and a group pile interaction analysis module; and a calculation result output subprogram interface, which comprises a single pile nonlinear response calculation result display and output module and a group pile nonlinear response result display and output module.

[0019] Compared with the prior art, the application has the following advantages:

[0020] 1. The analysis method and the interface of the software system are simple and easy to operate, and meet the actual engineering requirements for analyzing the horizontal response of group piles under complex load conditions.

[0021] 2. The LGROUP-AS V1.0 is used to analyze the horizontal group pile effect and response under the action of passive soil loads such as adjacent pile penetration, slope and surcharge and pile head horizontal load, the horizontal group pile effect, group pile stress and deformation response analysis results under different relative positions and different group pile configurations are obtained, the analysis and calculation and evaluation of the horizontal bearing capacity of the group pile foundation are realized, the foundation is laid for further optimization of the group pile configuration design, and the influence of subsequent engineering activities on the existing group pile foundation is further evaluated. The calculation file saving function in Excel format is provided, the user can input the basic calculation parameters in the software panel text box, select the appropriate foundation deformation calculation method, and output and save the obtained horizontal group pile effect and group pile stress and deformation calculation results.

[0022] 3. The input functions of group pile load parameters, soil layer parameters, group pile configuration parameters and free field soil body displacement parameters are provided, including free field soil body displacement depth distribution, groundwater position, basic physical and mechanical property parameters of soil layers, group pile arrangement mode, group pile loading mode and the like, and the rationality of the basic input parameters is judged during the input process through the reasonable interval range of each input data.

[0023] 4, Integrated pile foundation response analysis methods represented by nonlinear Winkler beam method and Poulos elastic analysis method, and through the extension of the modified Poulos method, it is expanded from active pile group effect analysis method to pile group effect analysis method under complex load conditions. Among them, the influence of pile-soil interaction on nonlinear response analysis of single pile is fully considered, the influence of pile group effect on pile-soil interaction relationship under different loading modes and different pile group configurations is analyzed, and its further influence on horizontal response of pile group is analyzed. The value of calculation unit length is based on the value standard of conventional pile response analysis, and can be flexibly set according to the calculation requirements; The pile-soil interaction relationship of single pile can be described based on the form recommended by API specification in marine geotechnical engineering or hyperbolic curve.

[0024] 5, The quantitative evaluation of horizontal pile group effect and response under the action of passive soil load such as adjacent pile penetration, slope and surcharge and pile head horizontal load is realized. According to the displacement of free field soil at different relative positions of pile group, the evaluation of pile group effect and the calculation of pile response are realized. The results of pile group effect and pile stress and deformation response analysis can be reflected in the software through the displacement of free field soil at each single pile position in pile group, pile bending moment, pile shear force and pile displacement distribution diagram, and finally saved as Excel format file for output. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the main program interface of LPILEGROUP V1.0 settlement calculation software.

[0026] Figure 2 It is the calculation interface schematic diagram of LGROUP-AS V1.0 four subprograms.

[0027] Figure 3 It is the interface schematic diagram of LGROUP-AS V1.0 software effectiveness verification.

[0028] Figure 4 It is the interface schematic diagram of LGROUP-AS V1.0 calculation parameter input completion.

[0029] Figure 5 It is the interface schematic diagram after clicking "result display" and "output to file" button.

[0030] Figure 6 It is the error prompt schematic diagram in pile parameter input.

[0031] Figure 7 It is the error prompt schematic diagram of soil layer parameter input.

[0032] Figure 8 It is the error prompt and soil displacement distribution display schematic diagram of soil displacement input.

[0033] Figure 9 Input diagram for load boundary condition.

[0034] Figure 10 Error input diagram for load boundary condition.

[0035] Figure 11 Input box for calculating length of single pile nonlinear response.

[0036] Figure 12 Diagram for displaying calculation results of single pile nonlinear response.

[0037] Figure 13 Input box for calculating length of single pile elastic response.

[0038] Figure 14 Diagram for displaying calculation results of group pile response.

[0039] Figure 15 Diagram for displaying document data content of "basic parameters" tag of calculation file.

[0040] Figure 16 Diagram for outputting nonlinear single pile response data.

[0041] Figure 17 Diagram for outputting group pile response data. DETAILED DESCRIPTION

[0042] In order to more clearly describe the technical content of the present application, further description will be made in combination with specific embodiments.

[0043] A group pile response analysis method under complex load conditions comprises the following steps for analyzing the group pile response:

[0044] S1: based on the nonlinear foundation beam model theory, the flexural differential equation of the pile is subjected to finite difference by combining the central difference method, and the single pile body response under complex load considering the nonlinear interaction between the pile and the soil is solved;

[0045] S2: based on the elastic theory method, the finite element method is combined to solve the elastic pile body response of the single pile and the group pile under complex load, which can consider the continuity of the soil body;

[0046] S3: based on the results of S2, the elastic additional group pile head displacement is solved, and the group pile head displacement considering the nonlinear interaction between the pile and the soil and the influence of the group pile effect is obtained by adding the calculation results of each single pile nonlinear response;

[0047] S4: Based on the nonlinear foundation beam model theory, the single pile-soil interaction curve is adjusted by Y multiplier for each single pile in the group pile, so that the obtained pile head displacement is equal to the group pile head displacement obtained in S3, and the Y multiplier represents the group pile effect at this time;

[0048] When the pile head translation occurs, the single pile head displacement is equal but only the total load is known, and the group pile response is analyzed according to the following steps:

[0049] S1: The single pile head load is the same, based on the nonlinear foundation beam model theory, the single pile body response under complex load is analyzed by combining the central difference method to carry out finite difference on the pile flexural differential equation, and the nonlinear interaction between the pile and the soil is analyzed.

[0050] S2: The single pile head load is the same, based on the elastic theory method, the elastic pile body response of the single pile and the group pile under complex load is solved by combining the finite element method, and the soil continuity can be considered.

[0051] S3: Based on the results of S2, the elastic additional group pile head displacement is further solved, and the group pile head displacement considering the nonlinear interaction between the pile and the soil and the group pile effect is obtained by adding the calculation results of each single pile nonlinear response.

[0052] S4: Based on the conditions that the single pile head displacement is equal and the sum of the single pile head loads is known, the single pile head load is redistributed until the pile head distribution load and the group pile head displacement satisfying the above two conditions are obtained.

[0053] S5: Based on the nonlinear foundation beam model theory, the single pile-soil interaction curve is adjusted by Y multiplier for each single pile in the group pile, so that the obtained pile head displacement is equal to the group pile head displacement obtained in S4, and the Y multiplier represents the group pile effect at this time.

[0054] In the embodiment, the complex load condition refers to the group pile loading condition subjected to the pile head load and the passive soil load distributed along the pile body.

[0055] Running environment of the software system of the application

[0056] 1. Hardware environment

[0057] CPU: 2.0 GHz or above, and the recommended configuration is dual-core 2.0 GHz or above;

[0058] Memory: 512 MB, and the recommended memory capacity is 1 GB;

[0059] Video card: no special requirements; sound card: no special requirements;

[0060] Display: 14 inches or above flat panel or liquid crystal display, and the recommended resolution is 1024x768 or higher.

[0061] 2. Software environment

[0062] Operating system: Windows 7-64 bit system, Windows 10-64 bit system;

[0063] Tool software: Office 2003 and above.

[0064] 3. Software installation and running method

[0065] Double-click to run LGROUP_AS.exe, and the main program interface of the group pile response analysis calculation software containing basic development information of the software will be started. Figure 1 After the software validity is verified, click the calculation parameter input subprogram interface, pile body response analysis subprogram interface and calculation result output subprogram interface activated by the corresponding control to start the calculation, which are shown in (a), (b), (c) and (d) respectively. Figure 2

[0066] Software usage instructions

[0067] 1. Main program interface of group pile horizontal response calculation software under complex load conditions

[0068] The main program interface of the group pile horizontal response analysis software under complex load conditions mainly verifies the software authorization validity, and activates the three subprogram interfaces according to the calculation needs. Figure 1 After the main program calculation interface is activated, first click the "software validity" button to verify the software authorization. The current software authorization adopts the physical address authorization verification mode. Only when the computer physical address matches the software built-in physical address format, the software can be normally authorized and run. After the software authorization is successful, Figure 1 the "calculation parameter" drop-down menu is activated at the same time. To ensure the time sequence of the software calculation before and after, Figure 1 in the secondary menu of the "calculation parameter" drop-down menu in the menu bar, only the "pile body parameter" option is activated, and the other options are still in the unactivated mode, as shown in Figure 3 Similarly, complete the calculation parameter input module content in the order of "soil layer parameter" - "free field soil displacement" - "load parameter".

[0069] After all the parameters in the "calculation parameter" drop-down menu are input, activate the "pile body response calculation" drop-down menu, and complete the group pile horizontal pile body response analysis in the order of the secondary menu "single pile nonlinear response analysis" - "single pile elastic analysis" - "group pile elastic analysis" - "group pile interaction analysis", as shown in Figure 4 .

[0070] ​After completing the second-level menu "Single Pile Nonlinear Response Analysis," simultaneously activating the second-level menus "Result Display" and "Output to File" within the "Calculation Results Output" dropdown menu allows you to display and output the single pile nonlinear response in the software. After completing the second-level menu "Pile Group Interaction Analysis," you can display and output the pile group horizontal response in the software. See [link to relevant documentation]. Figure 5 (a) Clicking the "Output File" button in the secondary menu will select the location to save the calculation results file. See [link / reference]. Figure 5 (b)

[0071] 2. Calculation parameter input subroutine interface

[0072] The program interface uses a manual calculation mode, which employs a step-by-step method, requiring the user to input parameters level by level. This results in relatively frequent human-computer interaction. The operation process of the manual calculation mode will be explained in detail below.

[0073] exist Figure 2 Click the "Authorize Verification" button to activate the "Calculation Parameters" drop-down menu. Figure 1 In the "Calculate Parameters" button, enter the parameters in the following order: "Pile Body Parameters" - "Soil Layer Parameters" - "Free Site Soil Displacement" - "Load Parameters". Figure 2 Interfaces shown in (a), 2(b), 2(c), and 2(d). By experiencing each step of the software's operation, understand the software's basic input and output parameters and grasp its working characteristics.

[0074] 2.1 Pile Body Parameter Input Module

[0075] After completing the authorization verification, first activate the "Pile Parameters" submenu in the "Calculation Parameters" drop-down menu. Click the button to enter the pile parameter input module. The pile parameter input module is mainly for inputting basic pile configuration parameter data, including pile group layout, pile inner diameter, outer diameter, pile length, and pile elastic modulus. Furthermore, the program only supports situations where all individual piles in a pile group have the same dimensions and material properties.

[0076] Figure 2 (a) The pile body parameter input box should be set according to the specific pile body parameters in actual calculations. The data entered in the input box are, in order: number of pile rows, number of columns, pile layout method, pile spacing s1, pile spacing s2, pile body elastic modulus, outer diameter, pile length, and inner diameter. The number of pile rows should be parallel to the loading direction and the input direction of the free site soil displacement, and the total number of piles should not exceed 100. There are three pile layout methods: rectangle, square, and triangle (quincunx). Pile spacing s2 is only activated when the rectangle layout method is used. The pile body elastic modulus, pile length, pile outer diameter, and inner diameter should be within a reasonable range; otherwise, after clicking the "Parameter Input" button, the parameters cannot be entered into the parameter confirmation list box on the right, and an error message will pop up. See [link to relevant documentation].Figure 6 The outer diameter of the pile must not exceed the pile spacing, and the inner diameter of the pile must not exceed the outer diameter; otherwise, an error message will pop up. See below. Figure 6 .

[0077] 2.2 Soil Parameter Input Module

[0078] After selecting the save location for the calculation results file, first activate the "Soil Layer Parameters" menu button in the "Calculation Parameters" drop-down menu. Clicking this will take you to the soil layer parameter input module. The soil layer parameter input module primarily allows you to input basic soil layer parameter data, including the location of the groundwater level, soil layer depth, and basic physical and mechanical properties of the strata. Furthermore, the methods for determining pile-soil interaction relationships include two categories: the "API method" and the "hyperbolic method."

[0079] Figure 2 (b) The soil layer parameter input table is active. In actual calculations, the specific soil layer parameters should be entered. The data to be entered in the table should be, in order: soil name, layer thickness, unit weight, soil compression modulus, soil elastic modulus, pile-soil interaction relationship, internal friction angle, and cohesion. After entering the soil layer parameters, click the "Save" button to store the data and return to the main menu interface. The soil compression modulus can be determined based on consolidation experiments, and the elastic modulus is generally set to 3-5 times the soil compression modulus. The input values ​​of the soil layer parameters in the table must be within a reasonable range, and the soil depth must be greater than the pile length; otherwise, clicking the "Save" button will trigger a corresponding error message. Figure 7 (a)(b)(c)(d)(e)) cannot return to the main menu interface.

[0080] 2.3 Free Site Soil Displacement Input Module

[0081] Complete the "Soil Layer Parameters" input module and click [here]. Figure 2 After clicking the "Save" button in (b), activate the "Free Site Soil Displacement" menu button in the "Calculation Parameters" drop-down menu. Click it to enter... Figure 2 In the free site soil displacement input module in (c), the pile number will be automatically loaded from the pile group number in the pile body parameter input module in 4.2.1 in the drop-down menu. Each individual pile in the pile group is numbered in the order from left to right and from top to bottom, which is the same as the output order of the subsequent pile body stress deformation response data.

[0082] After selecting the pile number in the left drop-down menu, the "add" button in the lower left corner is activated. The actual free-field soil displacement parameters at the location of the single pile can be inputted. The input form is the depth below the soil surface and the free-field soil displacement value at that depth, both in meters. It should be noted that the direction of soil horizontal displacement is parallel to the direction of the number of rows of pile groups. After the load input is complete, clicking the "delete" button can complete the corresponding operation on the data in the table. Then click the "OK" button to draw the free-field soil displacement distribution of the soil at the selected pile location in the chart on the right side to further confirm the data. If there are still piles without inputted free-field soil displacement, clicking the "OK" button will prompt a reminder to input the soil displacement parameters at other single pile locations. If all the soil displacement parameters at the single pile locations have been inputted, the "save" button on the right side is activated.

[0083] Clicking the "save" button will verify all the soil displacement parameters. For the free-field soil displacement at any single pile location, the input data needs to be greater than or equal to 2 rows, otherwise an error prompt will be given Figure 8 (a)(b)(c). After the data in the table meets the requirements, the main interface will be returned and the "load parameter" secondary menu will be activated.

[0084] 2.4 Load parameter input module

[0085] Clicking the "load parameter" secondary menu button activates the uppermost drop-down menu in the load boundary condition input box, and the software interface is shown as Figure 2 (d).

[0086] The following analysis considers only the translation of the pile head, i.e. the pile head angle is 0. Group pile analysis generally includes two boundary conditions: ① the total pile head load is known, and the displacement of each single pile head is equal; ② the load of each single pile head is known, but the displacement is different, as shown in Figure 9 (a).

[0087] After selecting the pile head load displacement boundary condition, the second drop-down menu is activated. If option ① is selected, only the total pile head load value needs to be inputted in the right text box. Clicking the "input" button in the lower left corner can input the data into the list box. Clicking the "delete" button can also perform the corresponding "delete" operation. If option ② is selected, the pile number will be automatically loaded in the left drop-down menu (see Figure 9 (b)), according to the number of pile groups in the pile body parameter input module in 4.2.1. Each single pile in the pile group is numbered from left to right and from top to bottom, which is the same as the subsequent pile body stress and deformation response data output sequence. In this case, the load of each single pile head needs to be inputted. If the pile head load is 0, input 0.

[0088] After the input of parameters is completed, click the "Save" button. If the input of load parameters is in a reasonable range, the main menu will be returned, and the "Pile Response Analysis" drop-down menu and the "Single Pile Nonlinear Pile Response" secondary menu will be activated. If the input parameters do not meet the requirements, the software will give corresponding error messages, as shown in the following figure: Figure 10 (a) (b) (c) are shown.

[0089] 3. Pile Response Analysis Subprogram Interface

[0090] The pile response analysis subprogram interface also uses a manual calculation mode for calculation. The manual mode uses a step-by-step method, and the software user clicks the buttons in sequence to calculate.

[0091] 3.1 Single Pile Nonlinear Response Analysis Module

[0092] After the input of parameters is completed, the "Single Pile Nonlinear Response Analysis" menu button in the "Pile Response Analysis" drop-down menu will be activated. After clicking, the pop-up window prompt shown in the following figure appears. The default value for the unit length is 0.1 m. The user can determine the unit length according to their own experience, as shown in the following figure: Figure 1 After confirmation, the "Single Pile Nonlinear Response Analysis" is performed. For the case where the pile head load of each single pile is known, the single pile shaft stress and deformation response under the action of the pile head load is obtained, considering the nonlinear pile-soil interaction relationship. For the case where the pile head load position of each single pile is known, the single pile shaft stress and deformation response under the action of the average pile head load is obtained, considering the nonlinear pile-soil interaction relationship. Figure 11 After the single pile nonlinear response analysis is completed, the "Result Display" button in the "Calculation Result Output" drop-down menu is activated. After clicking, the "Single Pile Response" button can be selected to display the free-field displacement at the single pile position, as well as the bending moment, pile shaft displacement, and other single pile shaft stress and deformation response results, as shown in the following figure:

[0093] Figure 12

[0094] 3.2 Group Pile Response Analysis Module

[0095] After the single pile nonlinear response analysis module is completed, the "Single Pile Elastic Analysis" and "Group Pile Elastic Analysis" buttons in the "Pile Response Analysis" drop-down menu are gradually activated. After clicking, the pop-up window prompt shown in the following figure appears. The default value for the unit length is 1 m. The user can determine the unit length according to their own experience, as shown in the following figure: Figure 13 After the calculation is completed, the "Group Pile Interaction Analysis" button is activated. Similar to the single pile nonlinear response analysis module, in the single pile elastic analysis, for the case where the pile head load of each single pile is known, the single pile shaft stress and deformation response under the action of the pile head load is obtained. For the case where the pile head load position of each single pile is known, the single pile shaft stress and deformation response under the action of the average pile head load is obtained. ​​

[0096] Click the "group pile interaction analysis" button, for the known each single pile pile head load, iterative determination of each single pile Y multiplier in group pile; for each single pile pile head load position, first according to the group pile pile head displacement is equal, iterative determination of each single pile pile head load distribution, and then iterative determination of each single pile Y multiplier in group pile.

[0097] After the completion of group pile interaction analysis, activate the "result display" button in the "calculation result output" drop-down menu, click, click "group pile response" button, you can choose to display the free field displacement of each single pile position in group pile, and the bending moment, pile displacement and other group pile pile stress deformation response results, see Figure 14 "calculation result output" drop-down menu "input to file", prompt, determine the save location and save the data, see Figure 5 (b).

[0098] 4. Output file (table file) content description

[0099] 4.1 file naming

[0100] The following is the naming format of the file naming and data document label.

[0101] 4.1.1 calculation file naming

[0102] After clicking the "output to file" button in the "calculation result output" drop-down menu, the project name input box pops up, enter the project name, and the output automatically creates a calculation file and is named "project name.xls".

[0103] 4.1.2 calculation file label naming

[0104] The calculation (table) file must contain the "basic parameters" document label, which mainly stores the basic calculation parameter data;

[0105] After the completion of single pile nonlinear response calculation, the subroutine interface further adds the single pile nonlinear response results of each single pile in group pile, including pile displacement, bending moment, shear force distribution calculation results in the calculation (table) file, stored in the "single pile response" label. After the completion of group pile interaction analysis calculation, the subroutine interface further adds the group pile response calculation results of each single pile in group pile, including pile displacement, bending moment, shear force distribution calculation results in the calculation (table) file, stored in the "group pile response" label.

[0106] 4.2 basic parameters

[0107] The basic parameter data contained in the calculation file (table) file has 14 items, corresponding to the text box input items, check box selection items, drop-down box selection items, etc. in the corresponding position of the calculation software. According to the analysis of the working condition, most of the parameters are mandatory items, and a small part of the parameters are optional items, such as Figure 15 (a) shown.

[0108] The "basic parameters" label also includes soil layer parameters and free field displacement input parameters at each single pile position, as shown in Figure 15 (b) (c) shown.

[0109] 1. The first item is a mandatory item, which inputs the calculation item name and names the.xls calculation result file with the calculation section name.

[0110] 2. The second item is a mandatory item, which is the number of rows of pile groups, and needs to be greater than 1 row and less than or equal to 6 rows. If the input does not meet the requirements, the program will report an error.

[0111] 3. The third item is a mandatory item, which is the number of columns of pile groups, and needs to be greater than 1 column and less than or equal to 6 columns. If the input does not meet the requirements, the program will report an error.

[0112] 4. The fourth item is a mandatory item, which is the pile arrangement mode, including triangular (plum blossom), rectangular and square three pile arrangement modes. If the input does not meet the requirements, the program will report an error.

[0113] 5. The fifth item is a mandatory item, which is the pile length. Considering the actual situation, the pile length should be greater than or equal to 5m and not more than 100m. If the input does not meet the requirements, the program will report an error.

[0114] 6. The sixth item is a mandatory item, which is the elastic modulus of the pile body. Considering the actual situation, the value should be greater than 10MPa and not more than 300MPa. If the input does not meet the requirements, the program will report an error.

[0115] 7. The seventh item is a mandatory item, which is the outer diameter of the pile. Considering the actual situation, the value should be not less than 0.1m and not more than 3m. If the input does not meet the requirements, the program will report an error.

[0116] 8. The eighth item is a mandatory item, which is the inner diameter of the pile. Considering the actual situation, the value should be not more than the outer diameter of the pile and not less than 0.1m. If the input does not meet the requirements, the program will report an error.

[0117] 9. The ninth item is a mandatory item, which is the pile spacing in the loading direction. Considering the actual situation, the value should be greater than the outer diameter of the pile and not more than 10 times the outer diameter of the pile. If the input does not meet the requirements, the program will report an error.

[0118] 10. The tenth item is a required entry (when the pile arrangement is square, this item is not activated), which is the pile spacing in the direction perpendicular to the load direction. Considering the actual situation, the value should be greater than the outer diameter of the pile and not greater than 10 times the outer diameter of the pile. If the input does not meet the requirements, the program will report an error.

[0119] 11. The eleventh item is a required entry, which is the groundwater depth, which should be greater than or equal to 0. If the input does not meet the requirements, the program will report an error.

[0120] 12. The twelfth item is a required entry, which is the soil layer calculation depth, which should be greater than or equal to the groundwater depth and equal to the sum of the thicknesses of each soil layer in the soil layer parameter input table. If the input does not meet the requirements, the program will report an error.

[0121] 13. The thirteenth item is a required entry, which is the load boundary condition, including two cases: ① the total pile head load is known, and the displacement of each single pile is equal; ② the pile head load of each single pile is known, but the displacement is different.

[0122] 14. The fourteenth item is a required entry, which is the total load when the load boundary condition is case ① in 13; when it is case ②, the pile head loads of each single pile will be listed in turn.

[0123] 15. Columns C to J are the soil layer parameter information input in the soil layer parameter input interface. The parameter input requirements are consistent with the foregoing, see Figure 15 (b).

[0124] 16. After column K, the free-field soil displacement parameters at the position of each single pile will be listed in turn. The parameter input requirements are consistent with the foregoing, see Figure 15 (c).

[0125] 4.3 Single pile response data

[0126] From column 1, input the nonlinear single pile response data into the "Single Pile Response" tab. For each pile, output the pile response in the order of depth - pile body displacement - depth - pile body moment - depth - pile body shear. The output depth corresponds to the position of each element node in the nonlinear foundation beam calculation, and corresponds to the output of the pile body response at that position, see Figure 16 .

[0127] 4.4 Group pile response data

[0128] Input the group pile response data obtained after group pile interaction analysis into the "Group Pile Response" tab. The first two columns are Y multiplier data.

[0129] From the 3rd column, for each pile, the pile responses are output in the order of depth-pile body displacement-depth-pile body bending moment-depth-pile body shear force. The output depth corresponds to the position of each element node in the nonlinear foundation beam calculation, and corresponds to the output of the pile response at this position, see Figure 17 .

Claims

1. A method for analyzing the response of a group of piles under complex loading conditions, characterized in that: It comprises: When the pile head translation occurs and the load acting on the pile head of each single pile in the group is known, the response of the group of piles is analyzed according to the following steps: S1: Based on the nonlinear foundation beam model theory, the finite difference of the pile deflection differential equation is carried out by combining the central difference method, the single pile body response under complex load considering the nonlinear interaction between pile and soil is solved; S2: Based on the elastic theory method, the elastic pile body response of single pile and group of piles under complex load considering the continuity of soil is solved by combining the finite element method; S3: Based on the results of S2, the elastic additional group pile head displacement is solved, and the group pile head displacement considering the nonlinear interaction between pile and soil and the group pile effect is obtained by adding the nonlinear response calculation results of each single pile; S4: Based on the nonlinear foundation beam model theory, the Y multiplier is used to adjust the single pile-soil interaction curve, so that the obtained pile head displacement is equal to the group pile head displacement obtained in S3, and the Y multiplier represents the group pile effect at this time; When the pile head translation occurs and the total load is known, the response of the group of piles is analyzed according to the following steps: S1: Based on the nonlinear foundation beam model theory, the finite difference of the pile deflection differential equation is carried out by combining the central difference method, the single pile body response under complex load is analyzed, and the nonlinear interaction between pile and soil is considered; S2: Based on the elastic theory method, the elastic pile body response of single pile and group of piles under complex load considering the continuity of soil is solved by combining the finite element method; S3: Based on the results of S2, the elastic additional group pile head displacement is solved, and the group pile head displacement considering the nonlinear interaction between pile and soil and the group pile effect is obtained by adding the nonlinear response calculation results of each single pile; S4: Based on the condition that the pile head displacement of each single pile is equal and the sum of the pile head load of each single pile is known, the pile head load of each single pile is redistributed until the pile head distribution load and the group pile head displacement satisfying the above two conditions are obtained; S5: Based on the nonlinear foundation beam model theory, the Y multiplier is used to adjust the single pile-soil interaction curve, so that the obtained pile head displacement is equal to the group pile head displacement obtained in S4, and the Y multiplier represents the group pile effect at this time; The complex loading condition refers to the loading condition of the group of piles under the action of the pile head load and the passive soil load distributed along the pile body.

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