Layout design method of shield machine cutter

Abstract

A layout design method for shield machine cutters includes: determining the interlayer wear uniformity of the shield machine cutter disc based on a statistical method and in combination with multiple sample data; determining the vertical layout of the shield machine cutter disc based on the interlayer wear uniformity of the shield machine cutter disc; establishing a finite element model of a single-layer shield machine cutter disc, wherein the finite element model uses the mechanical parameters of the shield machine cutter disc and the characteristic parameters of the plane layout as model inputs, and uses the intralayer wear uniformity as simulation output; determining the plane layout of the shield machine cutter disc based on the intralayer wear uniformity of the shield machine cutter disc. The present invention studies the plane layout and vertical layout of the shield machine cutter disc in detail, focusing on optimizing the intralayer wear uniformity and the interlayer wear uniformity, thereby effectively reducing the total wear amount and improving the service life and excavation efficiency of the cutter disc.

Description

Technical Field

[0001] The invention belongs to the field of shield machine cutter heads, and in particular relates to a layout design method for shield machine cutters. Background Art

[0002] With the acceleration of urbanization, the development and utilization of underground space is increasing. As one of the important forms of underground space development, the demand for tunnel engineering is also growing. As the core equipment for tunneling, the shield machine undertakes multiple tasks such as tunneling, support, and soil discharge. Its cutterhead design and tool layout are crucial to tunneling efficiency and construction quality. How to optimize the shield machine cutterhead layout to improve tunneling efficiency and tool life has become the focus of engineering and technical personnel.

[0003] At present, the layout design of shield machine cutterheads mostly adopts a combination of empirical rules and numerical simulation. Among them, the "small cutter height difference and narrow spacing" layout principle is a common design method. Its basic idea is to loosen the soil first with the highest leading tearing cutter (the first layer of tearing cutter), and then loosen the soil layer by layer with the subsequent leading tearing cutters, so that the wear of the first layer of tearing cutters is higher than that of the subsequent tearing cutters, thereby giving full play to the advantages of layered layout.

[0004] Although the "small cutter height difference and narrow spacing" layout principle can work effectively under general geological conditions, it still has the following significant defects under special soil and complex geological conditions. The first is excessive wear: under special soil conditions, the wear amount of the cutter may vary significantly, resulting in premature failure of some cutters, which seriously reduces the overall excavation efficiency. For example, in highly abrasive sand layers, the wear rate of the first layer of tearing cutters is much higher than expected, which not only speeds up the replacement frequency of cutters, but also may cause unplanned downtime. Excessive wear will further lead to uneven interlayer wear: the wear of cutters between different layers is inconsistent, and the advantages of interlayer layout cannot be fully utilized. For example, in strata with alternating hard rocks and soft soils, the cutters of each layer are subjected to different forces and wear unevenly, affecting the overall excavation stability. Correspondingly, uneven interlayer wear will further lead to uneven wear within the layer, that is, within the same layer of cutter disc, the wear amount of the cutter may also vary greatly, resulting in unbalanced cutter disc operation and increased equipment maintenance and replacement frequency. Therefore, how to reasonably optimize the layout design of the shield machine cutter disc is an urgent problem to be solved. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the purpose of the present invention is to solve the above-mentioned defects and further propose a layout design method for shield machine cutters.

[0006] The present invention adopts the following technical solution.

[0007] The first aspect of the present invention discloses a layout design method for a shield machine cutter, the method comprising steps 1 to 4;

[0008] Step 1, based on statistical methods and combined with multiple sample data, determine the interlayer wear uniformity of the shield machine cutter head;

[0009] Step 2, based on the interlayer wear uniformity of the shield machine cutter head, determine the vertical layout of the shield machine cutter head;

[0010] Step 3, establishing a finite element model of a single-layer shield machine cutterhead, wherein the finite element model uses the mechanical parameters of the shield machine cutterhead and the characteristic parameters of the plane layout as model inputs, and uses the wear uniformity within the layer as the simulation output;

[0011] Step 4: Determine the plane layout of the shield machine cutterhead based on the uniformity of the in-layer wear of the shield machine cutterhead.

[0012] Furthermore, in the cutterhead layout design of the shield machine, the tool distribution of the outer ring includes rock breaking tools from the first to the third layers and cutting tools from the fourth to the fifth layers.

[0013] Furthermore, in step 1, the interlayer wear uniformity W of the shield machine cutterhead is E The calculation formula is as follows:

[0014]

[0015] Among them, W i represents the wear uniformity of the i-th layer tool, i = 1, 2, 3, 4, 5, v = v1 / v2, R is the tool radius, v1 is the shield machine speed, v2 is the shield machine propulsion speed, L s is the shield tunneling distance, ε i The following fitting is obtained:

[0016]

[0017] Among them, ∈1, ∈2, ∈3, ∈4, ∈5, ∈6 are all unknown parameters, h1 is the first height difference, h2 is the second height difference, e is the void ratio, D r It is the relative density of soil.

[0018] Furthermore, step 2 is specifically to determine the vertical layout of the shield machine cutter head according to the genetic algorithm based on the interlayer wear uniformity of the shield machine cutter head, wherein the encoding vector of the individual in the genetic algorithm is C i =[h1, h2, W1, W2, W3, W4, W5, e, D r ], the fitness is the interlayer wear uniformity W E The calculation formula for .

[0019] Furthermore, the genetic algorithm includes steps S101 to S105;

[0020] Step S101, initializing the population, including: establishing a mapping relationship between the binary number of each element in each individual and the element, and obtaining the binary code corresponding to the individual;

[0021] Step S102, performing individual variation and gene exchange on the binary code;

[0022] Step S103, calculating the fitness corresponding to each individual;

[0023] Step S104, screening individuals based on the natural selection mechanism;

[0024] Step S105, determine whether the convergence condition is met, if so, output the individual with the smallest fitness; if not, return to step S102 for a new round of iteration.

[0025] Furthermore, the wear uniformity within the layer W i As shown below:

[0026]

[0027]

[0028] Among them, w i，r，θ represents the actual wear amount of the tool at the i-th layer at the polar coordinate position (r, θ), r min， r max Respectively represent the minimum and maximum polar radii for tool placement.

[0029] Further, step 3 specifically includes step 3.1 to step 3.3;

[0030] Step 3.1, based on the characteristic parameters of the plane layout of the shield machine cutter head, construct a geometric model and a physical model of the single-layer shield machine cutter head;

[0031] Step 3.2, based on the geometric model and physical model of the single-layer shield machine cutter head, construct a simulation model of the single-layer shield machine cutter head;

[0032] Step 3.3, according to the current mechanical parameters of the shield machine cutter head, calculate the uniformity of the in-layer wear of the shield machine cutter head.

[0033] A second aspect of the present invention discloses a terminal, including a processor and a storage medium; the characteristics are:

[0034] The storage medium is used to store instructions;

[0035] The processor is used to operate according to the instructions to execute the steps of the method described in the first aspect.

[0036] The third aspect of the present invention discloses a computer-readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the steps of the method described in the first aspect.

[0037] Beneficial effects of the present invention:

[0038] The present invention studies the planar layout and vertical layout of the shield machine cutter head in detail, focusing on optimizing the uniformity of wear within the layer and the uniformity of wear between layers, thereby effectively reducing the total wear and improving the service life and excavation efficiency of the cutter head. By optimizing the planar layout of the cutter, the wear of each cutter in the same layer is made more uniform, avoiding premature failure of a single cutter, thereby extending the overall service life of the cutter. By optimizing the vertical layout, the wear of the cutters between different layers is made uniform, avoiding excessive wear of the cutters in a certain layer and affecting the life of the entire cutter head. At the same time, the present invention takes into account that the volume of characteristic parameters is too large, and the mechanical parameters of the shield machine itself and the parameter characteristics of the soil have exceeded the calculation accuracy of the finite element model. Therefore, the idea of ​​divide and conquer is adopted, and the model is split based on the uniformity of wear within the layer, which simplifies the complexity of the model and ensures the feasibility of the entire scheme while ensuring the calculation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0040] Figure 1A This is a schematic diagram of the cutter distribution in the starting shaft to middle shaft section of the shield machine cutter head based on the "small cutter height difference and narrow spacing" layout principle.

[0041] Figure 1B This is a schematic diagram of the cutter distribution in the starting shaft to the middle shaft section of the shield machine cutter head based on the "large cutter height difference and wide spacing" layout principle.

[0042] Figure 2 It is a schematic diagram of the wear of the advance tearing cutter of the shield machine cutterhead based on the "small cutter height difference and narrow spacing" arrangement principle.

[0043] Figure 3 It is a schematic diagram of the Archimedean spiral of the shield machine cutterhead.

[0044] Figure 4A The intermediate crack growth capacity for different wear uniformities within the layers under different confining pressures is shown.

[0045] Figure 4B The lateral crack growth capacity of different layers with different wear uniformity under different confining pressures is shown.

[0046] Figure 5 The present invention is a flow chart of a layout design method of a shield machine cutter. DETAILED DESCRIPTION

[0047] The present application is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present application.

[0048] Figure 1A and Figure 1B A schematic diagram of the cutter arrangement between the starting shaft and the intermediate shaft of the two shield machine cutter heads is shown.

[0049] From a structural point of view, the cutterhead of a shield machine usually includes: cutting tools, rock breaking tools, auxiliary tools and central tools.

[0050] The cutting tools are usually arranged on the periphery of the cutterhead, surrounding the cutterhead. The spacing between them should be uniform to ensure that the excavation face is cut evenly. They are used to cut soil or soft rock, and are mainly responsible for cutting the soil or rock on the excavation face into smaller blocks or particles for easy removal.

[0051] Rock breaking tools are generally arranged on the periphery and middle area of ​​the cutter disc, and are often arranged alternately with cutting tools to take into account the crushing and cutting of soil layers of different hardness. They are used to crush hard rocks and can crush or split large pieces of rock, making them suitable for excavation in hard strata.

[0052] Auxiliary tools are usually placed on the edge and gap of the cutter disc to ensure effective cleaning and auxiliary cutting work. They are used to remove dirt or rock chips on the cutter disc, prevent the cutter disc from being blocked, and maintain the normal operation of the cutter disc.

[0053] The center cutter is arranged at the most central position of the cutter disc and is responsible for cutting and crushing the central part of the excavation face. It is used to process the soil or rock in the central area of ​​the cutter disc to ensure uniform excavation of the entire excavation face.

[0054] From the perspective of position distribution, the shield machine cutterhead usually includes an outer ring, an intermediate ring and a central part. It should be noted that the outer ring is mainly equipped with cutting tools and rock breaking tools, which can be arranged alternately. The intermediate ring can also be equipped with cutting tools and rock breaking tools, and some auxiliary tools can be added. The central part is usually equipped with central tools.

[0055] The present invention mainly discusses the wear of the five layers of tools of the peripheral ring, including the rock breaking tools of the first to third layers and the cutting tools of the fourth to fifth layers.

[0056] When selecting shield cutters, according to the characteristics of sand formations in some areas, the layout principle of "small cutter height difference and narrow spacing" can usually be adopted, such as Figure 1A Specifically, the tools of different heights, quantities and forms can be distributed in five layers to cover the cutting track of the entire cutter disc: the first layer of tools can be welded leading tools with a height of 260mm, which are used as the tools for first cutting the bottom layer; the second layer of tools can be welded leading tools with a height of 230mm, which are used as the tools for cutting the second layer of strata; the third layer of tools can be normal pressure replaceable leading tools with a height of 200mm, which are used as the tools for cutting the third layer of strata; the fourth layer of tools can be normal pressure replaceable scrapers with a height of 180mm, which are used as the tools for cutting the strata after the first layer of cutting leading tools excavates; the fifth layer of tools can be bolted scrapers with a height of 150mm, which are used as the tools for cutting the strata after the second layer of cutting leading tools excavates.

[0057] However, a lot of practice has proved that Figure 1A When the layout rules are used in special soils, atypical wear conditions may occur. Figure 2 As shown in the figure, the average wear coefficient of the first to third layers of welded pilot cutters is 0.02343 mm / km, which is greater than the wear coefficient of the first layer of welded pilot cutters, which is 0.01504 mm / km. This shows that after the first layer of tearing cutters were used for loosening and tilling, the second and third layers of tearing cutters did not loosen and till, but instead acted as scrapers to cut the soil, resulting in the wear coefficient of the subsequent layers of tearing cutters being greater than the wear coefficient of the first layer of tearing cutters, which is contrary to the original intention of the "small knife height difference and narrow spacing" design. This shows that under the stratum of this project, the "small knife height difference and narrow spacing" design cannot achieve efficient cutting of the soil, and a layered optimization layout is required.

[0058] Figure 1B The schematic diagram of the tool distribution of the starting shaft to the middle shaft of the shield machine cutter head based on the "large tool height difference and wide spacing" layout principle is shown. The first layer of tools is a welded lead cutter with a height of 280mm, which is used as the first tool to cut the stratum; the second layer of tools is divided into two categories; the first category is a welded lead cutter with a height of 230mm, which is used as the second layer of tools to cut the stratum; the third layer of tools is a normal pressure replaceable lead cutter with a height of 200mm, which is used as the third layer of tools to cut the stratum; the fourth layer of tools is a normal pressure replaceable scraper with a height of 180mm, which is used as the first layer of tools to cut the stratum after the lead cutter excavates; the fifth layer of tools is a bolt-type scraper with a height of 150mm, which is used as the second layer of tools to cut the stratum after the lead cutter excavates. After improvement, it was found that the wear can be effectively reduced by adjusting the height difference between the first layer of tools and the second layer of tools.

[0059] In summary, for the layout design of the shield machine cutterhead, simply considering the total wear has certain limitations. This is because when the tool wear of a certain layer is too large and the wear of other layers is small, it will seriously affect the service life of the entire cutterhead. Therefore, the present invention focuses on two key target characteristics: the uniformity of intra-layer wear caused by the plane layout and the uniformity of inter-layer wear caused by the vertical layout. Specifically, the uniformity of intra-layer wear means that the wear of each tool in the same layer of the cutterhead should be as uniform as possible to avoid excessive wear of a single tool and cause the cutterhead to be unbalanced. The uniformity of inter-layer wear requires that the tool wear between different layers should be consistent, so as to give full play to the advantages of the layered layout of the cutterhead and extend the overall life of the cutterhead. Meeting these two target characteristics can not only optimize the service life and excavation efficiency of the tool, but also effectively reduce the total wear.

[0060] The cutterhead of the shield machine is a circular disc with cutting tools distributed on it in a certain pattern. The cutting tools are constantly worn during the excavation process, so the service life of the shield machine becomes limited.

[0061] In the embodiment of the present invention, the plan layout of the cutter head of the shield machine can be described by using two features: the spiral shape and the distribution of the cutters.

[0062] like Figure 3 A schematic diagram of the Archimedean spiral of the shield machine cutter head is shown. The two characteristic parameters ρ0 and α can be used to describe the spiral shape of the shield machine cutter head, where ρ0 represents the polar axis in cm and α represents the polar angle in degrees.

[0063] The tool distribution includes two characteristic parameters: tool spacing d and distribution characteristic n of the leading tool. Tool spacing d refers to the average distance between adjacent tools on the Archimedean spiral, and the unit is cm. Understandably, the tools are usually evenly distributed on the Archimedean spiral. In order to ensure the force balance of the main bearing and prevent the destructive failure of the internal structure caused by uneven force, which will paralyze the entire shield machine cutter head. The distribution of leading tools should follow the principle of symmetry, that is, the arrangement of the tools satisfies the angle between two adjacent leading tools is θ=2π / n, and the angle between the outermost adjacent leading tools is 0.5θ. For example, if n=4, that is, the angle between adjacent leading tools is 90 degrees, and the angle between the outermost adjacent leading tools is 45 degrees.

[0064] In the embodiment of the present invention, for the vertical layout of the cutter head of the shield machine, the first height difference h1 and the second height difference h2 may be used as characteristic parameters for description.

[0065] The first height difference h1 refers to the height difference between the first layer of cutters and the second layer of cutters in the rock breaking cutter, and the second height difference h2 refers to the height difference between the second layer of cutters and the third layer of cutters in the rock breaking cutter, and the units are both Cm.

[0066] In an embodiment of the present invention, the inherent parameters may include the mechanical parameters of the shield machine itself and the parameter characteristics of the soil. The mechanical parameters of the shield machine itself include: tool radius R, shield machine speed v1, shield excavation distance L s and shield tunneling speed v2. The characteristic parameters of soil include: void ratio e and relative density D r .

[0067] Among them, the porosity ratio e refers to the ratio of the pore volume in the soil to the solid particle volume. It reflects the size of the voids in the soil, as shown in the following formula:

[0068]

[0069] Among them, V p Represents the volume of pores in the soil, V s is the volume of solid particles in the soil.

[0070] Relative density of soil D r It can be described by the standard penetration hammer number N, as shown below:

[0071]

[0072] Where τ is the effective overburden pressure.

[0073] According to current technical means, it is not difficult to think of a method that uses the finite element model to determine the fitness value of the shield machine cutter head design method and combines it with the evolutionary algorithm to obtain the optimal layout design. However, due to the complex structure and huge volume of the shield machine cutter head, and the need to introduce various parameters into the finite element model (for example: the mechanical parameters of the shield machine itself and the parameter characteristics of the soil), the accuracy of the simulation results of the finite element model itself will be greatly reduced.

[0074] How to select appropriate parameters to decompose the horizontal layout and the vertical layout is a technical problem that the present invention urgently needs to solve. Based on this, the present invention discloses a layout design method for shield machine cutters, wherein the layout design is composed of the plane layout of the shield machine cutterhead and the vertical layout of the shield machine cutterhead, such as Figure 5 As shown, it includes steps 1 to 4.

[0075] Step 1: Based on statistical methods and combined with multiple sample data, determine the interlayer wear uniformity of the shield machine cutter head.

[0076] Step 2: Determine the vertical layout of the shield machine cutter head based on the interlayer wear uniformity of the shield machine cutter head.

[0077] Step 3, establish a finite element model of a single-layer shield machine cutter head, wherein the finite element model uses the mechanical parameters of the shield machine cutter head and the characteristic parameters of the plane layout as model input, and uses the uniformity of wear within the layer as the simulation output.

[0078] Step 4: Determine the plane layout of the shield machine cutterhead based on the uniformity of the in-layer wear of the shield machine cutterhead.

[0079] In step 1, the interlayer wear uniformity W of the shield machine cutterhead is E The calculation formula is as follows:

[0080]

[0081] Among them, W i Indicates the wear uniformity of the i-th layer tool, i = 1, 2, 3, 4, 5, v = v1 / v2, ε i represents the wear coefficient of the soil on the i-th layer of tool, which depends on the characteristic parameters of the vertical layout and the characteristic parameters of the soil, ε i It can be obtained by fitting the following formula:

[0082]

[0083] Among them, ∈1, ∈2, ∈3, ∈4, ∈5, ∈6 are all unknown parameters, which can be fitted based on sample data and combined with statistical methods.

[0084] In some embodiments, the statistical method may be selected as logistic regression. More specifically, the least squares method may be used to minimize the difference between the predicted value and the actual value in the sample data, thereby determining the undetermined parameter. The fitting effect of the regression analysis may be evaluated by calculating the fitness value (such as R square), residuals, or cross-validation. Since regression analysis is a known method, its calculation process will not be described in detail.

[0085] The sample data refers to the actual data of the shield machine cutterhead. Its input includes the mechanical parameters of the shield machine cutterhead, the uniformity of intra-layer wear, the characteristic parameters of the vertical layout and the characteristic parameters of the soil. The output is the uniformity of inter-layer wear of the shield machine cutterhead.

[0086] Here we need to give an experimental explanation for the choice of wear uniformity within the layer. The middle crack growth capacity and lateral crack growth capacity are key indicators to measure the performance of the cutterhead under different confining pressures and soil characteristics. Figure 4A and Figure 4BThe middle crack extension capacity and lateral crack extension capacity of different in-layer wear uniformity under different confining pressures are shown respectively. It is not difficult to see from the figure that under different confining pressures, both the middle crack extension capacity and the measured crack extension capacity change linearly with the in-layer wear uniformity. Therefore, in the embodiment of the present invention, the in-layer wear uniformity can be selected as the characteristic parameter for the horizontal layout and vertical layout segmentation.

[0087] Among them, the wear uniformity within the layer W i It is defined as the uniformity of wear of each tool in different directions and lengths in a layer of tools, which can be expressed as follows:

[0088]

[0089]

[0090] Among them, W i,r，θ represents the actual wear amount of the tool at the i-th layer at the polar coordinate position (r, θ), r min , r max They represent the minimum and maximum polar radii of the tool arrangement respectively, and A represents the area of ​​the tool in the i-th layer.

[0091] In some embodiments, step 2 may use an evolutionary algorithm to determine the vertical layout of the shield machine cutter head. Specifically, the evolutionary algorithm may be a genetic algorithm. Since the object processed by the genetic algorithm is coded, each element needs to be converted into a corresponding binary number.

[0092] In step 2, the encoding vector is C i =[h1, h2, W1, W2, W3, W4, W5, e, D r ], the fitness is the interlayer wear uniformity W E The calculation formula for .

[0093] The genetic algorithm specifically includes steps S101 to S105.

[0094] Step S101, initializing the population, includes: establishing a mapping relationship between the binary number of each element in each individual and the element, and obtaining the binary code corresponding to the individual.

[0095] Assume that the number of individuals in the population is 500, each individual represents a shield machine cutter head structure, and the individual is encoded by the vector C j For each element in the encoding vector, it should be converted into a binary number. Where j = 1, 2, ..., 500.

[0096] More specifically, for each element in the encoding vector, its corresponding value range is first determined.

[0097] In step 2 and step 4 of the embodiment of the present invention, the genetic algorithm needs to be referenced. Therefore, h1 and n are selected here as an exemplary description of generating binary numbers. Among them, the value range of h1 can be a continuous interval, while the value range of n can only be a discrete integer.

[0098] Taking h1 as an example, its value range can be [20, 80]. Based on the value range of the element and the preset granularity, select the binary digits and establish the mapping relationship between the binary number and the element. Assuming the granularity is 3.75, the binary digits bit (4 in this case) can be determined by the following formula:

[0099] bit=floor(log2(t u -t l ) / f p )

[0100] Among them, [t l , t u ] indicates the value range, f p Indicates fine granularity, and floor indicates the symbol for rounding up.

[0101] It can be determined that the number of bits in h1 is 16, so the binary number b n The mapping relationship with the element (the current element λ is h1) is as follows:

[0102] λ=t u +b n ×(t u -t l ) / 2 bit

[0103] It is understandable that the above-mentioned fine-grained selection may also refer to the number of binary bits, and when the rounding up sign function is not used as much as possible, it is also possible to ensure that the number of binary bits is an integer.

[0104] Taking n as an example, its value range is 2 to 8 (integer). Since its granularity is fixed, that is, f p can only be 1, so the way to determine the number of binary digits remains unchanged, and the binary number b n The mapping relationship with element λ (the current element λ is n) is shown as follows:

[0105] λ=round(t u +b n ×(t u -t l ) / 2 bit )

[0106] Among them, round indicates the rounding symbol.

[0107] The value ranges of the other elements are: ρ0 is [50, 300]; α is [0, 45]; d is [20, 50]; h2 is [10, 50]; e is [0.4, 2]; D r The value range of W is [0, 1]; i The value range of is [0, 1]. The number of binary digits of all other elements can be selected as 4.

[0108] In an embodiment of the present invention, the binary numbers corresponding to all elements are sequentially concatenated to obtain a final binary code.

[0109] Step S102, performing individual variation and gene exchange on the binary code.

[0110] Individual variation refers to the reversal of the binary codes of some individuals in each round of iteration. Specifically, in each round of iteration, an associated reversal random number r1 is set for each individual, and its value range is [0, 1]. If the value of r1 is less than or equal to the reversal threshold, the binary code of the associated individual is reversed; if the value of r1 is greater than the reversal threshold, no change is made. In some embodiments, the reversal threshold can be 0.01, then approximately 1% of the individuals will be reversed in each round of iteration.

[0111] Inversion refers to replacing 0 with 1 and 1 with 0 in binary code.

[0112] Gene exchange refers to exchanging elements between pairs of individuals. Specifically, 500 individuals are paired in pairs to obtain 250 pairs of individuals, consisting of a first individual and a second individual; for any element in any pair of individuals, an associated exchange random number r2 is set, and its value range is [0, 1]. If the value of r2 is less than or equal to the exchange threshold, the binary numbers corresponding to the associated elements in the first individual and the second individual are exchanged; if the value of r2 is greater than the exchange threshold, no change is made. In some embodiments, the exchange threshold can be 0.25, then approximately 25% of the elements will be exchanged.

[0113] Step S103, calculating the fitness corresponding to each individual.

[0114] Step S104: screening individuals based on the natural selection mechanism.

[0115] First, the fitness of all individuals in the population is sorted from small to large. Then, based on a preset ranking threshold, the individuals with the largest ranking threshold number of fitness are deleted, and the individuals with the smallest ranking threshold number of fitness are copied, so that the total number of individuals in the population remains unchanged. In some embodiments, the ranking threshold can usually be 20% of the total number of individuals, for example, 100.

[0116] Step S105, determine whether the convergence condition is met, if so, output the individual with the smallest fitness; if not, return to step S102 for a new round of iteration.

[0117] The convergence condition can be set as follows:

[0118]

[0119] Among them, K max , K min are the maximum and minimum fitness values ​​of all individuals respectively, and σ is the convergence threshold, which can be taken as 0.01.

[0120] In some embodiments, step 3 specifically includes steps 3.1 to 3.3.

[0121] Step 3.1, based on the characteristic parameters of the plane layout of the shield machine cutter head, the geometric model and physical model of the single-layer shield machine cutter head are constructed.

[0122] The geometric model is a three-dimensional representation of the shield machine cutterhead, which details the geometric structure and dimensional characteristics of the shield machine cutterhead. In actual operation, software such as AutoCAD and CATIA can be used to create a geometric model, including defining the geometric structure, setting boundary conditions, meshing, and specifying physical properties and material parameters.

[0123] The physical model needs to include all the physical properties of the shield machine cutterhead, such as material properties (including density, elastic modulus, hardness, etc.), wear characteristics of the cutter, friction coefficient between the cutter and soil or rock, arrangement of the cutters and their spacing, and environmental conditions (such as pressure, temperature), etc. In some embodiments, the physical model can be constructed using software such as ANSYS and Simulink, which can help perform detailed physical property simulation and analysis.

[0124] Step 3.2, based on the geometric model and physical model of the single-layer shield machine cutter head, construct a simulation model of the single-layer shield machine cutter head.

[0125] The simulation model uses the geometric model and the physical model as basic inputs to perform virtual simulation experiments, thereby generating simulation output results, which may include tool wear distribution, stress and strain distribution, temperature field distribution, overall deformation of the cutterhead, etc. The simulation model is used to perform virtual simulation experiments, which include but are not limited to tool wear tests, cutterhead stress analysis, tool-soil interaction analysis, temperature influence analysis, etc. In some embodiments, simulation software such as COMSOL Multiphysics, OpenFOAM, and SolidWorks Simulation can be used to construct a simulation model of a single-layer shield machine cutterhead.

[0126] Step 3.3, according to the current mechanical parameters of the shield machine cutter head, calculate the uniformity of the in-layer wear of the shield machine cutter head.

[0127] In the simulation experiment, the characteristic parameters of the plane layout of the single-layer shield machine cutter head and the current mechanical parameters are taken as input. After being processed and integrated by the simulation model, the intra-layer wear uniformity of the shield machine cutter head is output.

[0128] Step 4 can also use evolutionary algorithm to determine the plane layout of the shield machine cutter head. Specifically, the evolutionary algorithm can also choose genetic algorithm. In step 4, the encoding vector is C i =[ρ0, α, d, n], the fitness is the finite element model of the single-layer shield machine cutterhead.

[0129] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0130] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A layout design method for shield machine cutters, characterized in that: The method comprises steps 1 to 4; Step 1, based on statistical methods and combined with multiple sample data, determine the interlayer wear uniformity of the shield machine cutter head; Step 2, based on the interlayer wear uniformity of the shield machine cutter head, determine the vertical layout of the shield machine cutter head; Step 3, establishing a finite element model of a single-layer shield machine cutterhead, wherein the finite element model uses the mechanical parameters of the shield machine cutterhead and the characteristic parameters of the plane layout as model inputs, and uses the wear uniformity within the layer as the simulation output; The wear uniformity within the layer is determined by the middle crack growth capacity and the lateral crack growth capacity; Wear uniformity within the layer W i As shown below: Among them, w i,r,θ represents the actual wear amount of the tool at the i-th layer at the polar coordinate position (r,θ), r min ,r max They represent the minimum and maximum polar axis radius of tool arrangement respectively; A represents the area of ​​the tool in the i-th layer; Step 4, based on the intra-layer wear uniformity of the shield machine cutter head, determine the plane layout of the shield machine cutter head; In the shield machine cutterhead layout design, the cutter distribution of the outer ring includes rock breaking cutters from the first to the third layers and cutting cutters from the fourth to the fifth layers; Interlayer wear uniformity W of shield machine cutterhead E The calculation formula is as follows: Among them, W i represents the wear uniformity of the i-th layer of the tool, i = 1, 2, 3, 4, 5, v = v1 / v2, R is the tool radius, v1 is the shield machine speed, v2 is the shield machine propulsion speed, L s is the shield tunneling distance, ε i The following fitting is obtained: Among them, ∈1,∈2,∈3,∈4,∈5,∈6 are all unknown parameters, h1 is the height difference between the first and second layers of the rock breaking tool, h2 refers to the height difference between the second and third layers of the rock breaking tool, and the unit is cm, e is the porosity ratio, D r It is the relative density of soil.

2. A shield machine cutter layout design method according to claim 1, characterized in that: Step 2 specifically includes determining the vertical layout of the shield machine cutterhead based on the interlayer wear uniformity of the shield machine cutterhead according to the genetic algorithm, where the encoding vector of the individual in the genetic algorithm is C i =[h1,h2,W1,W2,W3,W4,W5,e,D r ], the fitness is the interlayer wear uniformity W E The calculation formula for .

3. A shield machine cutter layout design method according to claim 2, characterized in that: The genetic algorithm includes steps S101 to S105; Step S101, initializing the population, including: establishing a mapping relationship between the binary number of each element in each individual and the element, and obtaining the binary code corresponding to the individual; Step S102, performing individual variation and gene exchange on the binary code; Step S103, calculating the fitness corresponding to each individual; Step S104, screening individuals based on the natural selection mechanism; Step S105, determine whether the convergence condition is met, if so, output the individual with the smallest fitness; if not, return to step S102 for a new round of iteration.

4. The layout design method of a shield machine cutter according to claim 1, characterized in that: Step 3 specifically includes steps 3.1 to 3.3; Step 3.1, based on the characteristic parameters of the plane layout of the shield machine cutter head, construct a geometric model and a physical model of the single-layer shield machine cutter head; Step 3.2, based on the geometric model and physical model of the single-layer shield machine cutter head, construct a simulation model of the single-layer shield machine cutter head; Step 3.3, according to the current mechanical parameters of the shield machine cutter head, calculate the uniformity of the in-layer wear of the shield machine cutter head.

5. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 4.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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