Method for calculating safety factor of interface between steel reinforced composite pile core pile and cement soil

Abstract

The application provides a calculation method of a safety factor of a cement-soil interface of a stiff composite pile core pile, and the method comprises the following steps: obtaining statistical characteristic parameters of the peak strength and the residual strength of the interface according to indoor shear tests; obtaining geometric parameters of the pile foundation and discretizing the interface into micro-units; constructing a random field based on the micro-unit coordinates and calculating the correlation between the micro-units; setting a target failure probability, an initial interval of the safety factor and a calculation precision; generating strength random variables through secondary Monte Carlo sampling and assigning values to each micro-unit after the correlation is modified; determining the strength state of the micro-unit through a strength trigger threshold, calculating the overall total resistance of the interface and the design external load and counting to obtain the failure probability; adjusting the safety factor interval through reverse iteration and linear interpolation based on the target failure probability until the precision requirement is met, and finally outputting the final safety factor. The calculation result is accurate and reliable, and the application provides a scientific basis for the design and safety evaluation of the stiff composite pile.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering pile foundation safety assessment technology, and in particular relates to a method for calculating the safety factor of the reinforced composite pile core-cement-soil interface. Background Technology

[0002] Reinforced composite piles are a type of pile composed of a core pile and cement-soil, possessing two load transfer interfaces: the core pile-cement-soil interface and the cement-soil-soil interface. The interfacial shear characteristics between the core pile and the cement-soil directly affect the overall bearing capacity and stability of the pile foundation. However, current research on the interfaces of reinforced composite piles in engineering mainly focuses on the cement-soil-soil interface, and the safety factor is mostly analyzed using traditional fixed-value methods. Research on the core pile-cement-soil interface is limited, and the uncertainties of interfacial bonding and friction are not considered. This leads to significant deviations between calculation results and actual engineering conditions, easily resulting in overly conservative or dangerous pile foundation safety assessments, which fail to meet the needs of engineering construction. Summary of the Invention

[0003] In view of this, the present invention aims to overcome the shortcomings of the above-mentioned problems in the prior art and proposes a method for calculating the safety factor of the reinforced composite core pile-cement-soil interface.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] In a first aspect, the present invention provides a method for calculating the safety factor of the reinforced composite core pile-cement-soil interface, comprising the following steps:

[0006] S1. The peak strength and residual strength data of the core pile-cement-soil interface were obtained through indoor core pile-cement-soil interface shear tests, and the mean values ​​of peak strength and residual strength were calculated. Standard deviation and the peak-residual intensity correlation coefficient ;

[0007] S2, Obtain the total design resistance at the interface of the stiffened composite pile. Then, according to the preset precision, the core pile-cement-soil interface is discretized along the pile length direction and the circumferential direction. Each micro-unit;

[0008] S3. Construct a random field based on the coordinates of the micro-units and calculate the correlation between the micro-units. ;

[0009] S4. Set the target failure probability required by the project. At the same time, an initial range of safety factors is given. and calculation accuracy ;

[0010] S5, based on Sub-Monte Carlo sampling generates peak intensity and residual intensity random variables that meet statistical characteristics. Combined with the spatial coordinates of each micro-unit, an interface intensity random field is constructed. The spatial correlation of the random variables is corrected by the correlation between micro-units, and each micro-unit is assigned a corresponding peak intensity and residual intensity.

[0011] S6. Set the intensity trigger threshold of the micro-unit. Determine the actual shear stress of each micro-unit one by one. and After determining the size relationship of all micro-units, the initial failure distribution of the entire interface is obtained.

[0012] S7. Calculate and compare the overall interface resistance in each Monte Carlo simulation. and design external loads The safety factor was obtained through statistics. and The corresponding failure probability and ;

[0013] S8, if the target failure probability exist Within the range, the average safety factor is obtained through linear interpolation. Corresponding failure probability and according to and Adjust the safety factor range according to the size relationship, when The final safety factor is Conversely, a new safety factor range is established and the iteration is repeated until... ;like Not here If the range is within the specified range, return to S4 to reset the initial range of the safety factor.

[0014] Furthermore, the peak-residual intensity correlation coefficient in S1 The calculation formula is:

[0015]

[0016] In the formula, and These represent the peak and residual strength of the k-th shear test group, respectively. and These are the peak value and the average residual strength obtained from shear tests, respectively.

[0017] Furthermore, the correlation between micro-units in S3 The calculation formula is:

[0018]

[0019] In the formula, and Let be the coordinates of the m-th and n-th micro-units, respectively. It represents the scale of random field fluctuations.

[0020] Furthermore, the formulas for calculating the peak intensity and residual intensity of the micro-units in S5 are as follows:

[0021]

[0022] In the formula, and Let be the peak value and residual intensity of the i-th micro-unit, respectively. and These are the peak value and the standard deviation of residual strength obtained from the shear test, respectively. and They are random variables of peak intensity and residual intensity, respectively. It conforms to a bivariate normal distribution. and The formula is as follows:

[0023]

[0024]

[0025] In the formula, It is a vector of zero. It is due to the correlation between micro-units The correlation matrix formed These are standardized normal random numbers.

[0026] Furthermore, the judgment criterion in S6 is: when When the micro-unit reaches its peak intensity, take ;when At that time, the micro-element takes the residual strength, and takes Intensity trigger threshold of micro-units The calculation formula is:

[0027]

[0028] In the formula, The safety factor preset in S4 or .

[0029] Furthermore, the overall resistance of the interface in S7 and design external loads The calculation formula is:

[0030]

[0031] In the formula, The area is the micro-unit.

[0032] Furthermore, in S7 if If the cumulative number of failures increases by one, the ratio of the number of failures to the Monte Carlo sampling is the failure probability.

[0033] Furthermore, the method for adjusting the safety factor range in S8 is as follows: when This makes ;when This makes .

[0034] Secondly, the present invention provides an electronic device, including a processor and a memory communicatively connected to the processor and used to store executable instructions of the processor, wherein the processor is used to execute the above-mentioned method for calculating the safety factor of the reinforced composite pile core-cement-soil interface.

[0035] Thirdly, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned method for calculating the safety factor of the reinforced composite pile core-cement-soil interface.

[0036] Compared with existing technologies, the method for calculating the safety factor of the reinforced composite core pile-cement-soil interface described in this invention has the following advantages:

[0037] (1) This invention proposes a safety factor for the core pile-cement-soil interface, and introduces random field theory to fully consider the uncertainty of the core pile-cement-soil interface strength and the correlation of micro-units, so that the safety factor calculation results are more in line with engineering practice.

[0038] (2) The present invention proposes to use a reverse iteration method based on the target failure probability when calculating the safety factor, which can flexibly set the failure probability of the project according to the safety level of the project, and realize the customized calculation of the safety factor.

[0039] (3) The present invention proposes to combine Monte Carlo simulation when calculating the safety factor, which greatly improves the accuracy and reliability of the calculation results and provides a scientific and accurate theoretical basis for the engineering design and safety assessment of stiffened composite piles. Attached Figure Description

[0040] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0041] Figure 1This is a flowchart of a method for calculating the safety factor of a rigid composite core pile-cement-soil interface proposed in this invention.

[0042] Figure 2 This is a schematic diagram of the micro-unit division of the rigid composite pile core-cement-soil interface according to the present invention. Detailed Implementation

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0044] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] Example 1

[0046] like Figure 1 As shown in the figure, the method for calculating the safety factor of the reinforced composite core pile-cement-soil interface proposed in this embodiment of the invention includes the following steps:

[0047] S1: First, through a large number of indoor core pile-cement-soil interface shear tests, the peak strength and residual strength data of the core pile-cement-soil interface were obtained. Then, the mean values ​​of the peak strength and residual strength were calculated using statistical analysis methods. Standard deviation and the peak-residual intensity correlation coefficient ;

[0048] Specifically, the peak-residual intensity correlation coefficient The calculation formula is:

[0049]

[0050] In the formula, and These represent the peak and residual strength of the k-th shear test group, respectively. and These are the peak value and the average residual strength obtained from shear tests, respectively.

[0051] S2: Obtain the total design resistance at the interface of the stiffened composite pile. Then, according to the preset precision, the core pile-cement-soil interface is discretized along the pile length direction and the circumferential direction. Each micro-unit;

[0052] S3: Construct a random field based on the coordinates of the micro-units and calculate the correlation between the micro-units. ;

[0053] Specifically, the correlation between micro-units The calculation formula is:

[0054]

[0055] In the formula, and Let be the coordinates of the m-th and n-th micro-units, respectively. It represents the scale of random field fluctuations.

[0056] S4: First, set the target failure probability required by the project. At the same time, an initial range of safety factors is given. and calculation accuracy ;

[0057] S5: Based on Sub-Monte Carlo sampling generates peak intensity and residual intensity random variables that meet statistical characteristics. Combined with the spatial coordinates of each micro-unit, an interface intensity random field is constructed. The spatial correlation of the random variables is corrected by the correlation between micro-units. Finally, each micro-unit is assigned a corresponding peak intensity and residual intensity.

[0058] Specifically, the peak intensity of the micro-unit and residual strength The calculation formula is:

[0059]

[0060] In the formula, and Let be the peak value and residual intensity of the i-th micro-unit, respectively. and These represent the peak value and the standard deviation of residual strength obtained from the shear test, respectively. and They are random variables of peak intensity and residual intensity, respectively. It conforms to a bivariate normal distribution. and The formula is as follows:

[0061]

[0062]

[0063] In the formula, It is a vector of zero. It is due to the correlation between micro-units The correlation matrix formed These are standardized normal random numbers.

[0064] S6: Set the intensity trigger threshold for the micro-unit. Determine the actual shear stress of each micro-unit one by one. and The size relationship. After all micro-units have been determined, the initial failure distribution of the entire interface can be obtained;

[0065] Specifically, the judgment criterion is that when When the micro-unit reaches its peak intensity, take ;when At that time, the micro-element takes the residual strength, and takes Intensity triggering threshold of micro-units The calculation formula is:

[0066]

[0067] In the formula, The safety factor preset in S4, i.e. or .

[0068] S7: Calculate and compare the overall interface resistance in each Monte Carlo simulation. and design external loads The safety factor was obtained through statistics. and The corresponding failure probability and ;

[0069] Specifically, the overall resistance of the interface and design external loads The calculation formula is:

[0070]

[0071] In the formula, The area is the micro-unit.

[0072] Specifically, if If the number of failures increases by one, the cumulative failure count is incremented by one. The ratio of the final failure count to the Monte Carlo sampling count is the failure probability.

[0073] S8: Probability of target failure exist Within the range, the average safety factor is obtained through linear interpolation. Corresponding failure probability and according to and Adjust the safety factor range according to the size relationship, when The final safety factor is Conversely, a new safety factor range is established and the iteration is repeated until... ;like Not here If the range is within the specified range, return to S4 to reset the initial range of the safety factor;

[0074] Specifically, the method for adjusting the safety factor range is as follows: when This makes ;when This makes .

[0075] Example 2:

[0076] This embodiment is a specific experiment for calculating the safety factor of a rigid composite core pile-cement-soil interface.

[0077] In this embodiment, the average peak strength was obtained through a large number of indoor core pile-cement-soil interface shear tests. Mean residual strength Peak intensity standard deviation residual strength standard deviation Peak-residual strength correlation coefficient Discretize the interface according to the pile length direction and the circumferential direction. Individual micro-units; setting the target failure probability Initial range of safety factor Calculation accuracy A schematic diagram of the micro-unit division is shown below. Figure 2 As shown.

[0078] Set the number of Monte Carlo samplings Next, Monte Carlo sampling was performed to generate... Group peak intensity and residual intensity random variables, combined with micro-unit correlation After correction, assign values ​​to each micro-unit. and .

[0079] calculate Number of failures at time Failure probability ; Number of failures at time Failure probability , Within the range.

[0080] Linear interpolation corresponding ,because The upper limit of the safety factor has been adjusted to 1.5, and the new safety factor range is as follows: Repeat the iteration.

[0081] After multiple iterations, the desired result was finally achieved. safety factor This is the safety factor of the stiffened composite pile interface in this project.

[0082] Example 3

[0083] An electronic device includes a processor and a memory communicatively connected to the processor and used to store executable instructions of the processor, the processor being used to execute the above-described method for calculating the safety factor of a stiffened composite pile core-cement-soil interface.

[0084] Example 4

[0085] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the aforementioned method for calculating the safety factor of a stiffened composite pile core-cement-soil interface.

[0086] The collection, storage, use, processing, transmission, provision, and disclosure of user personal information involved in this disclosure all comply with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0087] It should be noted that personal information collected from users should be used for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. Furthermore, such collection / sharing should only be conducted after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign an agreement / authorization that includes authorization of relevant user information before the user uses the function. In addition, any necessary steps must be taken to protect and safeguard access to such personal information data and ensure that others with access to personal information data comply with their privacy and procedures.

[0088] This disclosure is intended to provide implementation schemes for users to selectively prevent the use or access to their personal information data. Specifically, this disclosure is intended to provide hardware and / or software to prevent or block access to such personal information data. Once personal information data is no longer needed, risks can be minimized by restricting data collection and deleting data. Furthermore, where applicable, such personal information is de-identified to protect user privacy.

[0089] The acquisition, transmission, storage, use, and processing of data in this disclosed technical solution all comply with the relevant provisions of national laws and regulations.

[0090] It should be noted that in the embodiments disclosed herein, certain software, components, models, and other existing solutions in the industry may be mentioned. These should be considered as exemplary and are intended only to illustrate the feasibility of implementing the technical solution of this application. However, they do not mean that the applicant has used or necessarily used such solutions.

[0091] In the foregoing descriptions of the embodiments, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0092] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0093] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of this disclosure includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of this disclosure pertain.

[0094] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which programs can be printed, because programs can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0095] It should be understood that various parts of this disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0096] Those skilled in the art will understand that all or part of the steps of the methods described in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0097] Furthermore, the functional units in the various embodiments of this disclosure can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0098] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A method for calculating the safety factor of the reinforced composite core pile-cement-soil interface, characterized in that: Includes the following steps: S1. The peak strength and residual strength data of the core pile-cement-soil interface were obtained through indoor core pile-cement-soil interface shear tests, and the mean values ​​of peak strength and residual strength were calculated. Standard deviation and the peak-residual intensity correlation coefficient ; S2, Obtain the total design resistance at the interface of the stiffened composite pile. Then, according to the preset precision, the core pile-cement-soil interface is discretized along the pile length direction and the circumferential direction. Each micro-unit; S3. Construct a random field based on the coordinates of the micro-units and calculate the correlation between the micro-units. ; S4. Set the target failure probability required by the project. At the same time, an initial range of safety factors is given. and calculation accuracy ; S5, based on Sub-Monte Carlo sampling generates peak intensity and residual intensity random variables that meet statistical characteristics. Combined with the spatial coordinates of each micro-unit, an interface intensity random field is constructed. The spatial correlation of the random variables is corrected by the correlation between micro-units, and each micro-unit is assigned a corresponding peak intensity and residual intensity. S6. Set the intensity trigger threshold of the micro-unit. Determine the actual shear stress of each micro-unit one by one. and After determining the size relationship of all micro-units, the initial failure distribution of the entire interface is obtained. S7. Calculate and compare the overall interface resistance in each Monte Carlo simulation. and design external loads The safety factor was obtained through statistics. and The corresponding failure probability and ; S8, if the target failure probability exist Within the range, the average safety factor is obtained through linear interpolation. Corresponding failure probability and according to and Adjust the safety factor range according to the size relationship, when The final safety factor is Conversely, a new safety factor range is established and the iteration is repeated until... ;like Not here If the range is within the specified range, return to S4 to reset the initial range of the safety factor.

2. The method for calculating the safety factor of the reinforced composite core pile-cement-soil interface according to claim 1, characterized in that: The peak-residual intensity correlation coefficient in S1 The calculation formula is: ； In the formula, and These represent the peak and residual strength of the k-th shear test group, respectively. and These are the peak value and the average residual strength obtained from shear tests, respectively.

3. The method for calculating the safety factor of the reinforced composite core pile-cement-soil interface according to claim 1, characterized in that: The correlation between micro-units in S3 The calculation formula is: ； In the formula, and Let be the coordinates of the m-th and n-th micro-units, respectively. It represents the scale of random field fluctuations.

4. The method for calculating the safety factor of the reinforced composite core pile-cement-soil interface according to claim 2, characterized in that: The formulas for calculating the peak intensity and residual intensity of the micro-units in S5 are as follows: ； In the formula, and Let be the peak value and residual intensity of the i-th micro-unit, respectively. and These are the peak value and the standard deviation of residual strength obtained from the shear test, respectively. and They are random variables of peak intensity and residual intensity, respectively. It conforms to a bivariate normal distribution. and The formula is as follows: ； ； In the formula, It is a vector of zero. It is due to the correlation between micro-units The correlation matrix formed These are standardized normal random numbers.

5. The method for calculating the safety factor of the reinforced composite core pile-cement-soil interface according to claim 4, characterized in that: The judgment criterion in S6 is: when When the micro-unit reaches its peak intensity, take ;when At that time, the micro-element takes the residual strength, and takes Intensity trigger threshold of micro-units The calculation formula is: ； In the formula, The safety factor preset in S4 or .

6. The method for calculating the safety factor of the reinforced composite core pile-cement-soil interface according to claim 5, characterized in that: The overall resistance of the interface in S7 and design external loads The calculation formula is: ； In the formula, The area is the micro-unit.

7. The method for calculating the safety factor of the reinforced composite core pile-cement-soil interface according to claim 1, characterized in that: If in S7 If the cumulative number of failures increases by one, the ratio of the number of failures to the Monte Carlo sampling is the failure probability.

8. The method for calculating the safety factor of the reinforced composite core pile-cement-soil interface according to claim 1, characterized in that: The method for adjusting the safety factor range in S8 is as follows: when This makes ;when This makes .

9. An electronic device comprising a processor and a memory communicatively connected to the processor and used for storing processor-executable instructions, characterized in that: The processor is used to execute the method described in any one of claims 1-8.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it implements the method described in any one of claims 1-8.

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