A calculation method of ultimate bearing capacity of double-cavity pile foundation based on finite element simulation

Abstract

The present invention provides a method for calculating the ultimate bearing capacity of a double-cavern pile foundation based on finite element simulation, including: determining the influencing parameters of the ultimate bearing capacity of the double-cavern pile foundation; using finite element simulation to compare the ultimate bearing capacity of the double-cavern pile foundation with the ultimate bearing capacity of the single-cavern pile foundation under the influencing parameters; calculating the ultimate bearing capacity of the double-cavern pile foundation by the ultimate bearing capacity formula of the karst cave pile foundation, dividing it by the ultimate bearing capacity of the double-cavern pile foundation in the simulation to obtain a correction coefficient; and using the correction coefficient to correct the ultimate bearing capacity formula of the pile foundation. The present invention sets different working conditions, uses finite element simulation, compares the ultimate bearing capacity of the double-cavern pile foundation with the ultimate bearing capacity of the single-cavern pile foundation under the influencing parameters, analyzes the difference and change of the ultimate bearing capacity of the pile foundation between the single-cavern and double-cavern, calculates the ultimate bearing capacity of the double-cavern pile foundation by the ultimate bearing capacity formula of the pile foundation to obtain a correction coefficient, and uses the correction coefficient to correct the ultimate bearing capacity formula of the pile foundation, which can provide theoretical guidance for actual engineering.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical material data simulation, and in particular to a method for calculating the ultimate bearing capacity of a double-cavern pile foundation based on finite element simulation. Background Art

[0002] Physical model tests are usually used to simplify and abstractly analyze complex projects, which can help capture the main characteristics of engineering phenomena and better understand and explain actual projects. In actual projects, the karst geological conditions often contain multiple caves underground.

[0003] With the rapid development of numerical simulation, numerical analysis software has been increasingly used in the engineering field and plays an important role. Subsequently, various numerical calculation software has been updated and upgraded due to the emergence of the finite element method, and the role of numerical simulation technology in construction engineering has been further highlighted. The basic idea of ​​numerical simulation is to divide the soil and pile into grid units and set them by assigning mechanical factors. The advantages are fast, convenient and not affected by the test site.

[0004] Due to the considerable complexity of the cave roof in the karst area foundation, the cave roof is usually simplified into an elliptical fixed-support model, a cantilever beam-slab model, a fixed-support beam-slab model, and a simply supported beam-slab model. The simplified single cave ultimate bearing capacity calculation formula provides great convenience for carrying out theoretical calculations of corresponding models in the karst area. However, when there are multiple caves under the pile end, the application of the single cave formula in actual engineering is obviously not in line with the actual situation. Summary of the invention

[0005] The invention provides a method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation, which is used to solve the defects of the prior art in calculating the ultimate bearing capacity of a single cave and realize the calculation of the ultimate bearing capacity of a double-cavity pile foundation.

[0006] The present invention provides a method for calculating the ultimate bearing capacity of a double-cavern pile foundation based on finite element simulation, comprising: determining an influencing parameter of the ultimate bearing capacity of the double-cavern pile foundation; using finite element simulation to compare the ultimate bearing capacity of the double-cavern pile foundation with the ultimate bearing capacity of a single-cavern pile foundation under the influencing parameter; calculating the ultimate bearing capacity of the double-cavern pile foundation by using the ultimate bearing capacity formula of the karst cave pile foundation, and dividing the ultimate bearing capacity by the ultimate bearing capacity of the double-cavern pile foundation in the simulation to obtain a correction coefficient; and using the correction coefficient to correct the ultimate bearing capacity formula of the pile foundation.

[0007] According to a method for calculating the ultimate bearing capacity of a double cave pile foundation based on finite element simulation provided by the present invention, the influencing parameters affecting the ultimate bearing capacity of the double cave pile foundation include: the thickness of the cave roof, the horizontal distance between the double caves, and the vertical distance between the double caves.

[0008] According to a method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation provided by the present invention, finite element simulation is used to compare the ultimate bearing capacity of the double-cavity pile foundation with that of a single-cavity pile foundation under influencing parameters, including: establishing a finite element model; simulating and analyzing the changes in the ultimate bearing capacity of the double-cavity pile foundation with that of the single-cavity pile foundation under different influencing parameters.

[0009] According to a method for calculating the ultimate bearing capacity of a double cave pile foundation based on finite element simulation provided by the present invention, the ultimate bearing capacity formula of the cave pile foundation is:

[0010]

[0011]

[0012] Where: α is the punching angle; σ t is the uniaxial tensile strength of rock; θ is the internal friction angle of rock; h is the top plate thickness; d The pile diameter.

[0013] According to a method for calculating the ultimate bearing capacity of a double cave pile foundation based on finite element simulation provided by the present invention, different influencing parameters include: cave roof thickness, taking 3 d ~6 d, d The pile diameter.

[0014] According to a method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation provided by the present invention, different influencing parameters include: the horizontal distance between the double caves, taking 1 d ~8 d,d The pile diameter.

[0015] According to a method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation provided by the present invention, different influencing parameters include: the vertical distance between the double caves is -2 d ~3 d, d The pile diameter.

[0016] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a method for calculating the ultimate bearing capacity of a double cave pile foundation based on finite element simulation as described in any one of the above is implemented.

[0017] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation as described in any one of the above is implemented.

[0018] The present invention also provides a computer program product, including a computer program, which, when executed by a processor, implements any of the above-mentioned methods for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation.

[0019] The present invention provides a method for calculating the ultimate bearing capacity of a double-cavern pile foundation based on finite element simulation. The method determines the influencing parameters of the ultimate bearing capacity of the double-cavern pile foundation and sets different working conditions. Finite element simulation is used to compare the ultimate bearing capacity of the double-cavern pile foundation with that of the single-cavern pile foundation under the influencing parameters, analyzes the difference and change in the ultimate bearing capacity of the pile foundation between the single-cavern and double-cavern pile foundations, calculates the ultimate bearing capacity of the double-cavern pile foundation through the ultimate bearing capacity formula of the karst cave pile foundation, divides the ultimate bearing capacity of the double-cavern pile foundation in the simulation, obtains the correction coefficient, and then uses the correction coefficient to complete the correction of the ultimate bearing capacity formula of the pile foundation. The method can provide theoretical guidance for actual engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic flow chart of a method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation provided by the present invention;

[0022] Figure 2 It is a schematic diagram of the finite element model structure provided by the present invention;

[0023] Figure 3 It is a graph showing the variation of the pile load-settlement curve provided by the present invention as the horizontal spacing of the caves increases;

[0024] Figure 4 It is a summary diagram of the ultimate bearing capacity of various working conditions under different horizontal distributions of the caves provided by the present invention;

[0025] Figure 5 It is one of the stress cloud diagrams in the pile end foundation provided by the present invention;

[0026] Figure 6 This is the second stress cloud diagram in the pile end foundation provided by the present invention;

[0027] Figure 7 This is the third stress cloud diagram in the pile end foundation provided by the present invention;

[0028] Figure 8 This is the third stress cloud diagram in the pile end foundation provided by the present invention;

[0029] Fig. 9 It is a diagram showing the variation of the ultimate bearing capacity of the foundation piles when the vertical spacing of the karst caves provided by the present invention increases;

[0030] Fig.10 It is a graph showing the variation of the ultimate bearing capacity of the piles provided by the present invention with the vertical spacing of the caves;

[0031] Fig.11 The present invention provides a change in the ultimate bearing capacity of the piles at different vertical cave spacings;

[0032] Fig.12 It is a structural schematic diagram of the electronic device provided by the present invention.

[0033] Reference numerals:

[0034] 1. The first cave; 2. The second cave; 3. Pile foundation;

[0035] 210, upper cover layer; 220, medium weathered marl layer; 230, roof thickness;

[0036] 1210, processor; 1220, communication interface; 1230, memory; 1240, communication bus. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The present invention provides a method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation. Figure 1 , including the following steps:

[0039] Step 1: Determine the sensitivity parameters that affect the ultimate bearing capacity of pile foundation; determine the influencing parameters of the ultimate bearing capacity of double cave pile foundation.

[0040] In this embodiment, the sensitivity parameters affecting the ultimate bearing capacity of the pile foundation include the elastic modulus, cohesion and internal friction angle of the rock layer surrounding the pile foundation.

[0041] In this embodiment, the influencing parameters affecting the ultimate bearing capacity of the double-cavity pile foundation include: the thickness of the cave roof, the horizontal distance between the double caves, and the vertical distance between the double caves.

[0042] Step 2: Use finite element simulation to compare the ultimate bearing capacity of double-cavity pile foundation and single-cavity pile foundation under influencing parameters.

[0043] A finite element model was established to simulate and analyze the changes in the ultimate bearing capacity of double-cave pile foundation and single-cave pile foundation under different influencing parameters.

[0044] In this embodiment, see Figure 2 , a finite element model was established, in which the pile diameter was d = 4 cm, the pile length was 30 cm; the upper cover layer was 210 and 24 cm thick, the lower layer was a medium-weathered marl layer 220 and 96 cm thick, and the foundation pile was embedded in the rock to a depth of 4 cm; the cave size was 20 cm × 15 cm × 15 cm. The cave roof thickness H was 3 to 6 times the pile diameter, the cave horizontal spacing L was 1 to 8 days, the vertical overlap height of the two caves was 0-2 days or the vertical distance between the two caves was 0 to 3 d, d The pile diameter.

[0045] In this embodiment, the top plate thickness 230 is the thickness of the rock layer at the top of the cave. When the top plate thickness is 3, 4, 5 and 6 times the pile diameter, and other influencing parameters remain unchanged, the pile foundations under four different top plate thicknesses show similar pile top settlement laws, and the pile top settlement increases with the increase of vertical load. Figure 3 The "Code for Design of Building Foundations" and "Technical Specifications for Testing of Building Pile Foundations" stipulate the standard value determination method for the vertical ultimate bearing capacity of a single pile. For the slow deformation load displacement Q~S curve, the load corresponding to 40 mm settlement is taken as the ultimate bearing capacity of the pile. After the displacement similarity ratio conversion, the load corresponding to 1.33 mm settlement is the corresponding ultimate bearing capacity of the pile. Figure 4 The ultimate bearing capacity of each working condition under different horizontal distribution of karst caves is summarized in the figure. It can be seen from the figure that as the horizontal spacing of the karst caves increases, the ultimate bearing capacity decreases first and then increases, and finally returns to the ultimate bearing capacity level of the piles under the condition of a single karst cave, see Table 1 and Table 2.

[0046] The ultimate bearing capacity and reduction of pile foundation for different cave spacing L are shown.

[0047] Table 1 The ultimate bearing capacity of piles under various working conditions

[0048]

[0049] Table 2 Reduction of ultimate bearing capacity of pile foundation under different horizontal spacing of caves

[0050]

[0051] The reduction in ultimate bearing capacity in Table 2 is , where The ultimate bearing capacity of pile foundations at different horizontal spacings of caves in double cave formations;i It means that the horizontal spacing of caves is a multiple of the pile diameter distance; It is the ultimate bearing capacity of the foundation pile under the single cave condition with the same cave roof thickness.

[0052] In this embodiment, Figure 4 As can be seen from Table 1 and Table 2, the top plate thickness H When the pile side cave is farther from the horizontal position, the ultimate bearing capacity decreases first and then begins to recover gradually. H =3 d (12 cm), as the relative horizontal position of the side cave becomes farther, the ultimate bearing capacity of the pile decreases by 14.1%, 15.2%, 10.8%, 9.8%, 6.5%, 2.1%, 1.11% and 1.09% respectively compared with the single cave; H =4 d (16 cm), the ultimate bearing capacity of the piles decreased by 9.9%, 12.0%, 7.9%, 6.9%, 6.0%, 1.98%, 1.9% and 0.9% respectively compared with the single cave. H =5 d (20 cm), the ultimate bearing capacity of the piles decreased by 7.89%, 8.77%, 7.02%, 5.26%, 4.39%, 1.7%, 0.89% and 0.8% respectively compared with the single cave. H =6 d (24 cm), the reduction in pile bearing capacity is small enough, so it is considered that H ≥6 d When the thickness of the cave roof reaches or exceeds 6 times the pile diameter, the side cave no longer affects the transfer of pile end load in the rock formation, and the pile end load transfer mode returns to the single cave situation.

[0053] In this embodiment, when 3 d ≤ H <6 d When the ultimate bearing capacity of the pile increases, it shows a trend of decreasing first and then increasing as the relative position of the karst cave on the pile side increases. d ≤ L ≤2 d When the ultimate bearing capacity of the pile is greatly reduced compared with the single cave, the ultimate bearing capacity value is H =2 d As the horizontal spacing of the caves increases, L >2 d After that, the ultimate bearing capacity of the piles began to recover and L ≥6 dWhen the ultimate bearing capacity of the foundation pile is close enough to the ultimate bearing capacity of the single cave, it can be concluded that the influence range of the pile side cave on the bearing capacity of the foundation pile in the karst area is within 5 times the pile diameter and the distance between the caves. L ≥6 d When the pile side cave has no effect on the transfer of pile end load in the foundation, it can be considered that the pile side cave has no effect on the transfer of pile end load in the foundation. H =6 d When the ultimate bearing capacity of the pile increases with the increase of the distance between the caves, the overall change is very small, and the decrease in the ultimate bearing capacity is smaller than that in the case of a single cave. Therefore, it can be considered that H ≥6 d At this time, no matter how the horizontal spacing of the karst caves on the pile side changes, it will not affect the ultimate bearing capacity of the foundation piles.

[0054] In this embodiment, there will be different stress paths when the external load is transmitted downward through the pile foundation. The different transmission directions will also cause changes in the shear angle formed by the top plate and the spatial position of the failure surface, which will in turn affect the stability analysis of the cave foundation and the bearing capacity of the pile foundation. Therefore, it is very necessary to conduct a study on the changing trend of the shear angle under the pile end with different distribution conditions. When the pile end load is transmitted downward in the foundation, diffusion will occur to form a frustum-shaped diffusion zone. At this time, the acute angle formed by the hypotenuse of the frustum and the vertical direction is considered to be the shear angle of the shear mode. Top plate thickness H When the pile diameter is 3 times (12 cm), the stress cloud diagram in the pile end foundation can be found in Figure 5 , top plate thickness H When the pile diameter is 4 times (16 cm), the stress cloud diagram in the pile end foundation is as follows: Figure 6 , top plate thickness H When the pile diameter is 5 times (20 cm), the stress cloud diagram in the pile end foundation is as follows: Figure 7 , top plate thickness H When the pile diameter is 6 times (20 cm), the stress cloud diagram in the pile end foundation is as follows: Figure 8 .

[0055] In this embodiment, under the action of pile top load, the working condition groups under four different cave roof thicknesses all have stress concentration areas under the pile foundation. Due to the influence of the relative position of the two caves, the stress distribution difference in the pile end foundation is also very large. The pile side cave has a significant impact on the transmission of the pile end load in the foundation. When the cave spacing is small, the stress concentration area on the side of the side cave is obviously more extensive than the stress distribution of the same position of the single cave. This is because the existence of the cave will change the transmission trajectory of the pile end load in the foundation, especially at the corner of the cave, so when the relative position of the pile side cave is not too far, the stress diffusion area will extend to the side cave, and there will be a more obvious deviation phenomenon towards the pile side cave. As the pile side position becomes farther and farther, this influence becomes weaker and weaker. When the horizontal spacing of the caves reaches about 5 times the pile diameter, the stress diffusion area in the foundation also returns to the situation when there is a single cave.

[0056] In this embodiment, the punching angles under different working conditions are quantitatively taken and summarized, as shown in Table 3. The changes in the stress concentration area under the same pile can be seen from the above stress cloud diagram that when there is a side cave under the pile, the punching angle of the punching cone formed by the top plate is greater than that of a single cave. d ≤ L ≤2 d When the shear angle is significantly increased compared with the single cave, L =2 d When the shear angle reaches its maximum value. As the relative horizontal distance between the karst caves on the pile side continues to increase, when L >2 d The back punching angle begins to decrease, and when it reaches L ≥6 d The value of the shear angle is basically the same as that of the single cave, so it can also be considered that H ≥ 6d At this time, no matter how the horizontal spacing of the karst caves on the pile side changes, it will not affect the size of the shear angle.

[0057] Table 3 Punching angle values ​​under design conditions

[0058]

[0059] In this embodiment, when the vertical spacing of the caves S When the double caves are changed, different buried depths are modeled and calculated and analyzed. H Horizontal spacing of caves L , change the vertical spacing of the caves S, simulating the change of ultimate bearing capacity of pile foundation when the double caves are distributed differently. According to the discussion results of horizontal distribution of caves, when the horizontal distance of caves exceeds 5 times the distance of pile diameter or the thickness of cave roof reaches 6 times the distance of pile diameter, the change of cave position on the pile side will not affect the ultimate bearing capacity of pile foundation. Therefore, when discussing the different buried depths of caves in the following, only the cave roof thickness of 4 d ≤ H ≤5 d , the horizontal spacing of the caves is 1 d ≤ L ≤4 d Changes in pile bearing capacity within the range.

[0060] In this embodiment, when the cave roof thickness is H =4 d When the vertical spacing of the cave increases, the ultimate bearing capacity of the pile changes as follows: Fig. 9 As shown in the figure, when the cave roof thickness H =5 d When the ultimate bearing capacity of the pile changes with the vertical spacing of the cave, Fig.10 As shown, see Fig.11 The ultimate bearing capacity of the double cave condition is also reduced to varying degrees compared to that of the single cave condition. The ultimate bearing capacity of the pile foundation tends to increase gradually with the increase of the cave burial depth on the pile side. When the single cave is transformed into a double cave horizontal distribution, the ultimate bearing capacity of the pile foundation is greatly weakened; with the generation of vertical spacing between the caves, the value of the ultimate bearing capacity of the pile foundation begins to recover and increase. Different from the impact range when the caves are horizontally distributed, when the cave burial depth is unequal, the vertical spacing is about 3 times the pile diameter ( S =3 d ), at this time, the ultimate bearing capacity of the foundation pile has recovered to the value of the single cave condition. And no matter what the horizontal spacing L of the caves is, as the vertical spacing S The ultimate bearing capacity of the piles is increasing, and finally reaches the numerical level of the ultimate bearing capacity of a single cave.

[0061] Step 3: Calculate the ultimate bearing capacity of the double cave pile foundation using the ultimate bearing capacity formula of the cave pile foundation, and divide it by the ultimate bearing capacity of the double cave pile foundation in the simulation to obtain the correction coefficient. For the bearing capacity of the pile foundation with double caves, the internal friction angle of the rock layer has the greatest influence on the ultimate bearing capacity, and other parameters can be ignored.

[0062] The ultimate bearing capacity formula of cave pile foundation is:

[0063]

[0064]

[0065] Where:α is the punching angle; σ t is the uniaxial tensile strength of rock; θ is the internal friction angle of rock; h is the top plate thickness; d is the pile diameter, F p It only depends on the angle of internal friction.

[0066] When there are multiple caves under the pile end, the application of the formula in actual engineering is obviously not in line with the actual situation, because as the horizontal distance of the caves on the pile side increases, the shear angle of the pile end in the foundation increases compared with a single cave, and the formula This makes the calculated value of the ultimate bearing capacity of the piles larger and larger, which is consistent with Figure 4 The weakening effect of the karst cave on the middle pile side on the ultimate bearing capacity of the foundation pile is contradictory, so the ultimate bearing capacity correction coefficient of the double karst caves under the foundation pile is introduced. .

[0067] After calculating the ultimate bearing capacity under different working conditions using the above formula, it is divided by the ultimate bearing capacity of the double cave pile foundation in the simulation to obtain the correction coefficient in Table 4.

[0068] Table 4 Correction coefficient of the ultimate bearing capacity of piles for the horizontal spacing of caves

[0069]

[0070] When the horizontal spacing of the caves is within 2 times the spacing of the pile diameters, it can be regarded as a single cave condition of a large cave, and then connected with the theory of a single cave under the pile end. For the conditions of the same cave roof thickness, in addition to the rock geology, internal friction angle, etc., the span of the cave will also cause the change of the shear angle, which will increase with the increase of the cave span. When calculating the ultimate bearing capacity, it is necessary to appropriately increase the value of the shear angle based on the working conditions before the equivalence.

[0071] Step 4: Use the correction factor to complete the correction of the ultimate bearing capacity formula of the pile foundation.

[0072] The result of the correction of the ultimate bearing capacity formula of double cave foundation piles in karst areas is as follows: when the thickness of the cave roof is between 3 times and 5 times the pile diameter, and the horizontal spacing of the caves is within 5 times the pile diameter, the ultimate bearing capacity of the foundation pile is calculated according to the correction. When the horizontal spacing of the caves is a non-integer pile diameter, the shear angle and the correction coefficient are taken according to the linear interpolation method; when the thickness of the cave roof or the horizontal spacing of the caves is beyond 5 times the pile diameter, the ultimate bearing capacity of the foundation pile is regarded as a single cave and is calculated according to the original formula, that is:

[0073]

[0074] Where: Lis the horizontal spacing of the caves; d is the pile diameter; is the punching angle; h is the thickness of the cave roof; is the tensile strength of the rock.

[0075] In this embodiment, the engineering prototype corresponding to the physical model test is the pile diameter , Thickness of the top plate of the pile bottom cave , compressive strength The tensile strength is 1 / 50 to 1 / 20 of the compressive strength, so the tensile strength of rock is taken as .

[0076] In the case of a single cave, verify the reliability of the public announcement and substitute , , , and In the revised formula, the ultimate bearing capacity of the pile tip is:

[0077]

[0078] According to the indoor model test results, by multiplying the physical similarity condition by the load similarity constant, the characteristic value of the foundation bearing capacity in the engineering prototype is about 195000 kN, that is, , slightly larger than the result of formula verification.

[0079] In the case of double caves, verify the reliability of the public announcement and substitute , , , and To the corrected formula, combined with the correction coefficient table , the ultimate bearing capacity of the pile end is:

[0080]

[0081] Similarly, according to the indoor model test results, by multiplying the physical similarity condition by the load similarity constant, the characteristic value of the foundation bearing capacity in the engineering prototype is about 140000 kN, that is, , which is consistent with the formula verification results.

[0082] The present invention provides a method for calculating the ultimate bearing capacity of a double-cavern pile foundation based on finite element simulation. The method determines the influencing parameters of the ultimate bearing capacity of the double-cavern pile foundation and sets different working conditions. Finite element simulation is used to compare the ultimate bearing capacity of the double-cavern pile foundation with that of the single-cavern pile foundation under the influencing parameters, analyzes the difference and change in the ultimate bearing capacity of the pile foundation between the single-cavern and double-cavern pile foundations, calculates the ultimate bearing capacity of the double-cavern pile foundation through the ultimate bearing capacity formula of the karst cave pile foundation, divides the ultimate bearing capacity of the double-cavern pile foundation in the simulation, obtains the correction coefficient, and then uses the correction coefficient to complete the correction of the ultimate bearing capacity formula of the pile foundation. The method can provide theoretical guidance for actual engineering.

[0083] The following is a description of a double cave pile foundation ultimate bearing capacity calculation system based on finite element simulation provided by the present invention. The double cave pile foundation ultimate bearing capacity calculation system based on finite element simulation described below and the double cave pile foundation ultimate bearing capacity calculation method based on finite element simulation described above can refer to each other.

[0084] Fig.12 An example of a physical structure diagram of an electronic device is provided, and the electronic device may include: a processor 1210, a communication interface 1220, a memory 1230, and a communication bus 1240, wherein the processor 1210, the communication interface 1220, and the memory 1230 communicate with each other through the communication bus 1240. The processor 1210 may call the logic instructions in the memory 1230 to execute a method for calculating the ultimate bearing capacity of a double-cavern pile foundation based on finite element simulation, the method comprising determining an influencing parameter of the ultimate bearing capacity of the double-cavern pile foundation; using finite element simulation, comparing the ultimate bearing capacity of the double-cavern pile foundation with the ultimate bearing capacity of the single-cavern pile foundation under the influencing parameter; calculating the ultimate bearing capacity of the double-cavern pile foundation by the ultimate bearing capacity formula of the karst cave pile foundation, dividing it by the ultimate bearing capacity of the double-cavern pile foundation in the simulation to obtain a correction coefficient; and using the correction coefficient to correct the ultimate bearing capacity formula of the pile foundation.

[0085] In addition, the logic instructions in the above-mentioned memory 1230 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0086] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute a method for calculating the ultimate bearing capacity of a double cave pile foundation based on finite element simulation provided by the above-mentioned methods. The method includes: determining the influencing parameters of the ultimate bearing capacity of the double cave pile foundation; using finite element simulation to compare the ultimate bearing capacity of the double cave pile foundation with the ultimate bearing capacity of the single cave pile foundation under the influencing parameters; calculating the ultimate bearing capacity of the double cave pile foundation through the ultimate bearing capacity formula of the cave pile foundation, and dividing it by the ultimate bearing capacity of the double cave pile foundation in the simulation to obtain a correction coefficient; and using the correction coefficient to complete the correction of the ultimate bearing capacity formula of the pile foundation.

[0087] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it is implemented to execute a method for calculating the ultimate bearing capacity of a double cave pile foundation based on finite element simulation provided by the above-mentioned methods. The method includes: determining the influencing parameters of the ultimate bearing capacity of the double cave pile foundation; using finite element simulation to compare the ultimate bearing capacity of the double cave pile foundation with the ultimate bearing capacity of the single cave pile foundation under the influencing parameters; calculating the ultimate bearing capacity of the double cave pile foundation by the ultimate bearing capacity formula of the cave pile foundation, and dividing it by the ultimate bearing capacity of the double cave pile foundation in the simulation to obtain a correction coefficient; and using the correction coefficient to complete the correction of the ultimate bearing capacity formula of the pile foundation.

[0088] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work. Through the description of the above implementation methods, technicians in this field can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiment.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation, characterized in that: The following steps are involved: Determine the influencing parameters of the ultimate bearing capacity of double cave pile foundation; Finite element simulation is used to compare the ultimate bearing capacity of double-cavity pile foundation and single-cavity pile foundation under influencing parameters. The ultimate bearing capacity of the double-cavern pile foundation is calculated by the ultimate bearing capacity formula of the karst cave pile foundation, and divided by the ultimate bearing capacity of the double-cavern pile foundation in the simulation to obtain the correction coefficient; Use the correction factor to correct the ultimate bearing capacity formula of pile foundation; Among them, the ultimate bearing capacity formula of cave pile foundation is: Where: α is the punching angle; σ t is the uniaxial tensile strength of rock; θ is the internal friction angle of rock; h is the top plate thickness; d is the pile diameter; When the thickness of the cave roof is between 3 times and 5 times the pile diameter, and the horizontal spacing of the caves is within 5 times the pile diameter, the ultimate bearing capacity of the pile foundation is calculated according to the correction. When the horizontal spacing of the caves is a non-integer pile diameter, the shear angle and the correction coefficient are obtained according to the linear interpolation method; when the thickness of the cave roof or the horizontal spacing of the caves is beyond 5 times the pile diameter, the ultimate bearing capacity of the pile foundation is regarded as a single cave and is calculated according to the original formula, that is: Where: L is the horizontal spacing of the caves; d is the pile diameter; is the punching angle; h is the thickness of the cave roof; is the tensile strength of the rock.

2. The method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation according to claim 1 is characterized in that: The influencing parameters that affect the ultimate bearing capacity of the double cave pile foundation include: the thickness of the cave roof, the horizontal distance between the double caves, and the vertical distance between the double caves.

3. The method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation according to claim 2 is characterized in that: Finite element simulation is used to compare the ultimate bearing capacity of double-cavity pile foundation and single-cavity pile foundation under the influencing parameters, including: Establish finite element model; The changes of the ultimate bearing capacity of double-cavity pile foundation and single-cavity pile foundation under different influencing parameters are simulated and analyzed.

4. The method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation according to claim 3 is characterized in that: Different influencing parameters include: cave roof thickness, taking 3 d ~6 d, d The pile diameter.

5. The method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation according to claim 3 is characterized in that: Different influencing parameters include: horizontal distance between two caves, taking 1 d ~8 d, d The pile diameter.

6. The method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation according to claim 3 is characterized in that: Different influencing parameters include: the vertical distance between the two caves is -2 d ~3 d, d The pile diameter.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, a method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation as described in any one of claims 1 to 6 is implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it implements a method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation as described in any one of claims 1 to 6.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, it implements a method for calculating the ultimate bearing capacity of a double-cavity pile foundation based on finite element simulation as described in any one of claims 1 to 6.

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