A mechanical simulation method for the cutter head of an earth pressure balance shield machine during tunneling

Abstract

The present invention provides a mechanical simulation method for the cutterhead of an earth pressure balance shield machine during tunneling. The parameters obtained in steps S1 - S2 are processed by a discrete element software in step S3 to construct a soil discrete element model; in step S4, the discrete element software is used to set the operating parameters of the three-dimensional model of the shield machine imported into the soil discrete element model and run the simulation to obtain the simulation results; in step S5, the simulation results are used as the load input conditions and after finite element analysis, the stress and deformation conditions of the cutterhead panel, cutting tools, scraping tools and hob of the shield machine in the tunneling direction are obtained. Compared with the prior art, the present invention takes into account the influence of geological conditions on the performance of the cutterhead during tunneling. At the same time, during the simulation process, the cutterhead panel is no longer regarded as a simple rigid body, and the influence of the hob, cutting tools and scraping tools on the cutterhead of the shield machine is considered, overcoming the problem that many parameters cannot be accurately obtained and are simply ignored during the numerical simulation of traditional shield machines.

Description

Technical Field

[0001] The present invention relates to the technical field of shield machine equipment, and particularly relates to a mechanical simulation method for the cutterhead of an earth pressure balance shield machine during tunneling. Background Art

[0002] Currently, the design and force analysis of the cutterhead of an earth pressure balance shield machine mainly rely on theoretical models based on empirical formulas, structural analysis based on finite element software, and simulations based on discrete element software. Each of these methods has certain defects, specifically as follows:

[0003] 1) The theoretical model mainly calculates the total thrust and total torque of the cutterhead of the shield machine through empirical formulas. In this empirical formula, the loads acting on the cutterhead mainly include the earth pressure on the front of the cutterhead, the earth pressure on the side of the cutterhead, the earth pressure of the muck in the muck bin, and the frictional force generated by the contact between the rotating cutterhead and the soil. However, the real geological environment is complex and variable, and the empirical formula simplifies the complex interaction between the stratum and the shield machine to a large extent, resulting in relatively simple consideration factors and being unable to reflect the real stress state of the shield machine during tunneling in a complex stratum environment. It belongs to a relatively rough calculation.

[0004] 2) The simulation methods for the finite element analysis of the cutterhead structure of the shield machine mainly include establishing a mesh element model of the cutterhead and the soil body, and simulating the tunneling process of the cutterhead by killing and generating mesh elements; applying the reaction force of the static earth pressure on the shield machine face to simulate the support force received by the tunnel face during tunneling. This simulation method focuses on evaluating the disturbance and induced deformation of the stratum caused by shield machine construction. The shield machine is only used as one of the boundary conditions, and only the force on the cutterhead panel is considered, and the stress state of each hob on the cutterhead cannot be obtained; at the same time, the finite element mesh simulation is usually used for continuous media, and it is impossible to accurately simulate relatively complex discontinuous bodies such as sandy soil and rock.

[0005] 3) When using discrete element software to simulate the tunneling of the cutterhead of the shield machine, the cutterhead is regarded as a rigid body and cannot generate deformation and damage, which does not conform to the actual situation.

[0006] Based on the above defects, it is urgent to develop a mechanical simulation method for the cutterhead of an earth pressure balance shield machine during tunneling in a geological environment to relatively accurately reflect the real stress and deformation conditions of the cutterhead panel and various tools (including cutters, scrapers, and hobs) on the cutterhead during tunneling. Summary of the Invention

[0007] The purpose of the present invention is to provide a mechanical simulation method for the cutterhead of an earth pressure balance shield machine during tunneling, which is used to relatively accurately reflect the real stress and deformation conditions of the cutterhead panel and various tools (including cutters, scrapers, and hobs) on the cutterhead during tunneling, and improve the simulation credibility. The specific technical solution is as follows:

[0008] A mechanical simulation method for the cutter head of an earth pressure balance shield machine during tunneling, comprising the following steps:

[0009] Step S1: Determine the formation characteristics, project overview, and soil material parameters of the tunneling scenario of the earth pressure balance shield machine;

[0010] Step S2: Select the corresponding contact model according to the formation characteristics; use discrete element software to construct the contact model into a soil discrete element model; determine the contact parameters, particle size, and distribution data in the soil discrete element model;

[0011] Step S3: Set the soil material parameters in Step S1, the contact parameters, particle size, and distribution data in Step S2 in the discrete element software, and generate a soil simulation model after calculation by the discrete element software;

[0012] Step S4: First, use the modeling software CREO to process the tunneling system of the shield machine and generate a three-dimensional model of the shield machine; the tunneling system includes a cutter head, a shield body, and a screw conveyor, and the cutter head includes a cutter head panel and hob cutters, disc cutters, and scrapers arranged on the cutter head panel;

[0013] Secondly, after exporting and saving the three-dimensional model of the shield machine in the.stl format, import it into the soil simulation model; after import, the overburden depth and slope of the three-dimensional model of the shield machine need to be kept consistent with the project overview, and set the operating parameters in the three-dimensional model of the shield machine, including the shield machine propulsion speed, cutter head panel rotation speed, hob cutter rotation speed, and screw conveyor rotation speed; use discrete element software to perform a running simulation on the three-dimensional model of the shield machine; after the running simulation is completed, extract the simulation results through the post-processing module in the discrete element software, and the simulation results include the thrust and torque received by the cutter head panel, disc cutters, scrapers, and each hob cutter in the tunneling direction;

[0014] Step S5: Import the cutter head in the three-dimensional model of the shield machine into the finite element software for processing to obtain a finite element model of the cutter head, and use the thrust and torque received by the cutter head panel, disc cutters, scrapers, and each hob cutter in the tunneling direction obtained in Step S4 as the load input conditions of the finite element model of the cutter head, and apply them to the corresponding components in the finite element model of the cutter head respectively. After completing the finite element analysis, the stress and deformation conditions received by the cutter head panel, disc cutters, scrapers, and hob cutters of the shield machine in the tunneling direction can be obtained.

[0015] Optionally, in Step S4, the hob cutter rotation speed includes the rotation speed of each hob cutter arranged on the cutter head panel;

[0016] The method for determining the rotation speed of each hob cutter is as follows:

[0017] First, denote the angular velocity of the cutter head panel during tunneling as ω;

[0018] Secondly, arbitrarily select a hob, denoted as hob G1; determine the distribution position of hob G1 on the cutter head panel. Specifically, through measurement, obtain the radius of hob G1 as r1 and the distance between hob G1 and the center point of the cutter head panel as a;

[0019] Then, set the angular velocity of hob G1 to be ω1, and obtain ω1 through Equation (1):

[0020] ω1r1 = ωa (1)

[0021] Finally, determine the rotational speed of each hob by measuring the distribution positions of other hobs on the cutter head panel and combining with Equation (1).

[0022] Optionally, in step S1, the process of determining the formation characteristics, project overview, and soil material parameters is as follows:

[0023] First, determine the type of earth pressure balance shield machine that needs to be analyzed;

[0024] Secondly, determine the engineering section where the shield machine is applied, and the engineering section includes multiple consecutive construction sections;

[0025] Finally, select a certain construction section as the research section, obtain the geological exploration report of the research section, and determine the formation characteristics, project overview, and soil material parameters based on the geological exploration report.

[0026] Optionally, in step S2, the process of determining the particle size and distribution data in the soil discrete element model is as follows:

[0027] Perform a soil screening test on the soil in the research section, analyze the particle size distribution of the soil, and use the analysis results to determine the particle size and distribution data in the soil discrete element model;

[0028] In step S2, perform a repose angle test on the soil in the research section to determine the contact parameters in the soil discrete element model.

[0029] Optionally, in step S1, the soil material parameters include the density, Poisson's ratio, and elastic modulus of the soil.

[0030] Optionally, in step S1, the formation characteristics include at least one of sandy clay, silty clay, fine sand, and medium sand.

[0031] Optionally, when the formation characteristics are at least one of sandy clay, fine sand, and medium sand, the selected contact model in step S2 is Hertz - Mindlin;

[0032] When the formation property is silty clay, the contact model selected in step S2 is Hertz-Mindlin with JKR.

[0033] Optionally, in step S2, the contact parameters include the static friction coefficient between particles, the dynamic friction coefficient between particles, the elastic recovery coefficient between particles, the static friction coefficient between particles and the shield machine, the dynamic friction coefficient between particles and the shield machine, the elastic recovery coefficient between particles and the shield machine, and the energy density between particles and the shield machine.

[0034] Optionally, the discrete element software is EDEM software.

[0035] Optionally, the finite element software is ABAQUS software.

[0036] Applying the technical solution of the present invention has at least the following beneficial effects:

[0037] In the mechanical simulation method of the cutter head of the earth pressure balance shield machine during tunneling in the present invention, the parameters obtained in steps S1-S2 are processed by a discrete element software in step S3 to construct a soil discrete element model; in step S4, the discrete element software is used to set the operating parameters of the three-dimensional model of the shield machine imported into the soil discrete element model and run the simulation to obtain the simulation results; in step S5, the simulation results are used as the load input conditions and after finite element analysis, the stresses and deformations of the cutter head panel, cutters, scrapers and hob of the shield machine in the tunneling direction are obtained. Compared with the prior art, the present invention adopts a discrete element and finite element coupling numerical simulation method for the cutter head of the shield machine, which can take into account the influence of geological conditions on the performance of the cutter head during tunneling. At the same time, the cutter head panel is no longer regarded as a simple rigid body during the simulation process, and the influence of the hob, cutters and scrapers on the cutter head of the shield machine is considered, overcoming the problem that many parameters in the traditional numerical simulation of the shield machine cannot be accurately obtained and are simply ignored. The mechanical simulation method adopted by the present invention can relatively accurately reflect the true stress and deformation conditions of the cutter head panel and various cutters during the tunneling process of the shield machine underground, with high credibility, simple process and low operating cost, which is of great significance for the design of the shield machine.

[0038] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The following will refer to the drawings to further elaborate on the present invention in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0040] Figure 1 It is a flowchart of a mechanical simulation method for the cutter head of an earth pressure balance shield machine during tunneling in Embodiment 1 of the present invention. Specific implementation manners

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0042] Embodiment 1:

[0043] See Figure 1 , a mechanical simulation method for the cutter head of an earth pressure balance shield machine during tunneling, including the following steps:

[0044] Step S1: First, determine the model of the earth pressure balance shield machine to be analyzed; secondly, determine the engineering section where the shield machine is applied, and the engineering section includes a plurality of continuous construction sections; finally, select a certain construction section as the research section, obtain the geological exploration report of the research section, and determine the formation characteristics, engineering overview and soil material parameters according to the geological exploration report;

[0045] Step S2: First, select the corresponding contact model according to the formation characteristics, and then use the discrete element software to construct the contact model into a soil discrete element model;

[0046] Secondly, conduct a soil screening test on the soil in the research section, analyze the particle size distribution of the soil particles, and use the analysis results to determine the particle size and distribution data in the soil discrete element model; conduct a repose angle test on the soil in the research section to determine the contact parameters in the soil discrete element model;

[0047] Step S3: Set the soil material parameters in Step S1, the contact parameters in Step S2, and the particle size and distribution data in the discrete element software, and generate a soil simulation model that can replace the real soil environment after being calculated by the discrete element software;

[0048] Step S4: First, use the modeling software CREO to process the tunneling system of the shield machine and generate a three-dimensional model of the shield machine; the tunneling system includes a cutter head, a shield body and a screw conveyor, and the cutter head includes a cutter head panel and hob cutters, cutter knives and scraping knives arranged on the cutter head panel;

[0049] Secondly, after exporting and saving the 3D model of the shield machine in the.stl format, import it into the soil simulation model; after import, the overburden depth and slope of the 3D model of the shield machine need to be kept consistent with the project overview, and set the operating parameters in the 3D model of the shield machine, including the shield machine propulsion speed, cutter head panel rotation speed, hob rotation speed, and screw conveyor rotation speed; use the discrete element software to simulate the operation of the 3D model of the shield machine; after the operation simulation is completed, extract the simulation results through the post-processing module in the discrete element software, and the simulation results include the thrust and torque received by the cutter head panel, cutting tools, scraping tools, and each hob in the tunneling direction; it should be noted here that since the cutting tools and scraping tools are both fixed on the cutter head panel and do not move relative to the cutter head panel, the thrust and torque received by the cutting tools and scraping tools in the tunneling direction are the same as those of the cutter head panel.

[0050] Step S5: After importing the cutter head in the 3D model of the shield machine into the finite element software for processing, obtain the finite element model of the cutter head. Use the thrust and torque received by the cutter head panel, cutting tools, scraping tools, and each hob in the tunneling direction obtained in step S4 as the load input conditions for the finite element model of the cutter head, and apply them to the corresponding components in the finite element model of the cutter head respectively. After completing the finite element analysis, the stress and deformation conditions of the cutter head panel, cutting tools, scraping tools, and hobs of the shield machine in the tunneling direction can be obtained.

[0051] In step S4, the hob rotation speed includes the rotation speed of each hob set on the cutter head panel.

[0052] The method for determining the rotation speed of each hob is as follows:

[0053] First, record the angular velocity of the cutter head panel during the tunneling process as ω.

[0054] Secondly, select any one hob, denoted as hob G1; determine the distribution position of hob G1 on the cutter head panel. Specifically, measure the radius of hob G1 as r1 and the distance between hob G1 and the center point of the cutter head panel as a.

[0055] Then, set the angular velocity of hob G1 to be solved as ω1, and obtain ω1 through formula (1):

[0056] ω1r1 = ωa (1)

[0057] Finally, determine the rotation speed of each hob by measuring the distribution positions of other hobs on the cutter head panel and combining formula (1).

[0058] In step S1, the soil material parameters include the density, Poisson's ratio, and elastic modulus of the soil.

[0059] In step S1, the formation properties include at least one of sandy clay, silty clay, fine sand, and medium sand.

[0060] When the formation properties are at least one of sandy clay, fine sand, and medium sand, the contact model selected in step S2 is Hertz-Mindlin (no-slip);

[0061] When the formation property is silty clay, the contact model selected in step S2 is Hertz-Mindlin with JKR.

[0062] In step S2, the contact parameters include the static friction coefficient between particles, the dynamic friction coefficient between particles, the elastic recovery coefficient between particles, the static friction coefficient between particles and the shield machine, the dynamic friction coefficient between particles and the shield machine, the elastic recovery coefficient between particles and the shield machine, and the energy density between particles and the shield machine.

[0063] The discrete element software is EDEM software.

[0064] The finite element software is ABAQUS software.

[0065] In order to verify the credibility of the mechanical simulation method of the cutterhead of the earth pressure balance shield machine during tunneling described in Example 1 compared with the actual engineering data, the inventor uses the following case for comparative verification:

[0066] Taking the second phase project of Guangzhou Metro Line 14 as an example, the model of the earth pressure balance shield machine is ZTE6650 (42 hob cutters are arranged on the cutterhead panel). According to the geological exploration report of the research section, the formation property is determined to be silty clay, and the following soil material parameters are set: soil density 2200 kg / m 3 、soil elastic modulus 2.845×10 7 Pa, soil Poisson's ratio 0.27;

[0067] Due to the formation property being silty clay, the Hertz-Mindlin with JKR contact model is selected to construct the soil discrete element model. The contact parameters set in the soil discrete element model are as follows: the static friction coefficient between particles is 0.75, the dynamic friction coefficient between particles is 0.7, the elastic recovery coefficient between particles is 0.04, the static friction coefficient between particles and the shield machine is 0.25, the dynamic friction coefficient between particles and the shield machine is 0.6, the elastic recovery coefficient between particles and the shield machine is 0.001, and the energy density between particles and the shield machine is 8 J / m 3 ; the particle size in the soil discrete element model is set to a particle radius of 60 - 180 mm;

[0068] The propulsion speed of the shield machine is 0.75 mm / s, the rotational speed of the cutter head panel is 1.59 rpm, and the rotational speed of the screw conveyor is 80 rpm.

[0069] Since it is impossible to separately obtain the force data of the cutter head panel, hob, cutter, and scraper in actual engineering, the total thrust and total torque data of the entire cutter head are usually obtained through monitoring with pressure sensors, monitoring sensors, etc. Therefore, it is necessary to calculate the total thrust and total torque data of the entire cutter head through vector calculation from the simulation results extracted in step S4, that is, the thrust and torque data of the cutter head panel, cutter, scraper, and each hob in the tunneling direction.

[0070] In terms of the total thrust, the vector calculation method adopted is as follows:

[0071] First, the thrust and torque of the cutter head panel, cutter, scraper, and each hob in the X, Y, and Z coordinate axes directions are separately extracted through the post-processing module in the discrete element software;

[0072] Secondly, among the 42 hobs, any one hob is selected and denoted as hob i. The thrust of hob i in the X direction is denoted as F ix , the thrust in the Y direction is denoted as F iy , and the thrust in the Z direction is denoted as F iz (wherein, the F of the 42 hobs is shown in Table 1 iz data); then project the vectors of F ix , F iy , F iz in the three directions onto the tunneling direction of the cutter head, and the thrust of hob i in the tunneling direction can be obtained (if the tunneling direction is consistent with the direction of a certain coordinate axis, the thrust in this direction can be directly extracted);

[0073] Finally, sum up the thrusts of the cutter head panel, cutter, scraper, and all hobs in the tunneling direction, and the total thrust of the entire cutter head can be obtained. After calculation, the average value of this total thrust is 11775 kN; among them, the average value of the thrust of the cutter head panel is 10223 kN.

[0074] Similarly, in terms of the total torque, a vector calculation method similar to that of the total thrust is adopted to obtain the total torque.

[0075] Table 1 Thrust conditions of each hob in the Z direction

[0076]

[0077]

[0078] According to the records during the shield tunneling at the construction site of the second phase project of Guangzhou Metro Line 14, the engineering sections determined at the construction site include 20 consecutive construction sections, which are respectively denoted as Construction Section 1, Construction Section 2,...... and Construction Section 20; with the help of pressure sensors, monitoring sensors, etc., the total thrust data of the overall cutter head in each construction section are monitored and obtained, as shown in Table 2. According to Table 2, the average value of the total thrust of the overall cutter head of the shield machine within the said engineering section can be calculated to be 12740 kN, which is very close to the average value of 11775 kN of the total thrust of the overall cutter head obtained by simulation in Embodiment 1. This shows that the mechanical simulation method adopted in the present invention can relatively accurately reflect the true force and deformation conditions of the cutter head panel and various cutters during the tunneling process of the shield machine underground, and has a high credibility.

[0079] Table 2 Total Thrust Conditions of the Overall Cutter Head of the Shield Machine in Each Construction Section within the Engineering Section

[0080] Engineering section Driving mileage Thrust (kN) Construction section 1 YDK47+378.157 13000 Construction section 2 YDK47+376.657 12300 Construction section 3 YDK47+375.157 12900 Construction section 4 YDK47+373.657 13000 Construction section 5 YDK47+372.157 14500 Construction section 6 YDK47+370.657 13000 Construction section 7 YDK47+369.157 11500 Construction section 8 YDK47+367.657 12000 Construction section 9 YDK47+366.157 12500 Construction section 10 YDK47+364.657 12200 Construction section 11 YDK47+363.157 12000 Construction section 12 YDK47+361.657 11900 Construction section 13 YDK47+360.157 12100 Construction section 14 YDK47+358.657 13000 Construction section 15 YDK47+357.157 12600 Construction section 16 YDK47+355.657 12000 Construction section 17 YDK47+354.157 13400 Construction section 18 YDK47+352.657 14400 Construction section 19 YDK47+351.157 13500 Construction section 20 YDK47+349.657 13000

[0081] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A mechanical simulation method for the cutterhead of an earth pressure balance shield machine during tunneling, characterized in that, It includes the following steps: Step S1: Determine the formation characteristics, project overview, and soil material parameters of the earth pressure balance shield tunneling scenario; Step S2: Select the corresponding contact model according to the formation characteristics; use discrete element software to construct the contact model into a soil discrete element model; determine the contact parameters, particle size, and distribution data in the soil discrete element model; Step S3: Set the soil material parameters in Step S1, the contact parameters, particle size, and distribution data in Step S2 in the discrete element software, and generate a soil simulation model after calculation by the discrete element software; Step S4: First, process the tunneling system of the shield machine using the modeling software CREO and generate a 3D model of the shield machine; the tunneling system includes a cutter head, a shield body, and a screw conveyor, and the cutter head includes a cutter head panel and hob cutters, disc cutters, and scrapers arranged on the cutter head panel; Secondly, after exporting and saving the 3D model of the shield machine in the.stl format, import it into the soil simulation model; after import, the overburden depth and slope of the 3D model of the shield machine need to be kept consistent with the project overview, and set the operating parameters in the 3D model of the shield machine, including the shield machine propulsion speed, cutter head panel rotation speed, hob cutter rotation speed, and screw conveyor rotation speed; use the discrete element software to perform a running simulation on the 3D model of the shield machine; after the running simulation is completed, extract the simulation results through the post-processing module in the discrete element software, and the simulation results include the thrust and torque received by the cutter head panel, disc cutters, scrapers, and each hob cutter in the tunneling direction; Step S5: Import the cutter head in the 3D model of the shield machine into the finite element software for processing to obtain a finite element model of the cutter head, and use the thrust and torque received by the cutter head panel, disc cutters, scrapers, and each hob cutter in the tunneling direction obtained in Step S4 as the load input conditions for the finite element model of the cutter head, and apply them to the corresponding components in the finite element model of the cutter head respectively. After completing the finite element analysis, the stress and deformation conditions received by the cutter head panel, disc cutters, scrapers, and hob cutters of the shield machine in the tunneling direction can be obtained.

2. The mechanical simulation method of the cutter head of the earth pressure balance shield machine during tunneling according to claim 1, characterized in that, In Step S4, the hob cutter rotation speed includes the rotation speed of each hob cutter arranged on the cutter head panel; The method for determining the rotation speed of each hob cutter is as follows: First, denote the angular velocity of the cutterhead panel during the selected tunneling process as ; Secondly, select any hob, denoted as hob G1; determine the distribution position of hob G1 on the cutter head panel. Specifically, the radius of hob G1 is obtained through measurement as , and the distance from hob G1 to the center point of the cutter head panel is ; Then, set the angular velocity of the hob G1 to be determined as , and obtain it through Equation (1) : （1） Finally, by measuring the distribution positions of other hob cutters on the cutter head panel and combining with Equation (1), determine the rotation speed of each hob cutter.

3. The mechanical simulation method of the cutter head of the earth pressure balance shield machine during tunneling according to claim 1, characterized in that The process of determining the formation characteristics, project overview, and soil material parameters in Step S1 is as follows: First, determine the model of the earth pressure balance shield machine that needs to be analyzed; Secondly, determine the engineering section where the shield machine is applied, and the engineering section includes multiple continuous construction sections; Finally, select a certain construction section as the research section, obtain the geological exploration report of the research section, and determine the formation characteristics, project overview, and soil material parameters according to the geological exploration report.

4. The mechanical simulation method of the cutter head of an earth pressure balance shield machine during tunneling according to claim 3, characterized in that, In Step S2, the process of determining the particle size and distribution data in the soil discrete element model is as follows: Perform a soil screening test on the soil in the research section, analyze the particle size distribution of the soil, and use the analysis results to determine the particle size and distribution data in the soil discrete element model; In step S2, a repose angle test is performed on the soil mass in the research interval to determine the contact parameters in the discrete element model of the soil mass.

5. The mechanical simulation method of the cutter head of the earth pressure balance shield machine during tunneling according to claim 1, wherein, In step S1, the soil material parameters include the density, Poisson's ratio, and elastic modulus of the soil.

6. The mechanical simulation method of the cutter head of an earth pressure balance shield machine during tunneling according to claim 1, characterized in that, In step S1, the formation characteristics include at least one of sandy clay, silty clay, fine sand, and medium sand.

7. The mechanical simulation method of the cutter head of an earth pressure balance shield machine during tunneling according to claim 6, characterized in that, When the formation characteristics are at least one of sandy clay, fine sand, and medium sand, the contact model selected in step S2 is Hertz-Mindlin; When the formation characteristics are silty clay, the contact model selected in step S2 is Hertz-Mindlin with JKR.

8. The mechanical simulation method of the cutter head of an earth pressure balance shield machine during tunneling according to claim 7, characterized in that, In step S2, the contact parameters include the static friction coefficient between particles, the dynamic friction coefficient between particles, the elastic recovery coefficient between particles, the static friction coefficient between particles and the shield machine, the dynamic friction coefficient between particles and the shield machine, the elastic recovery coefficient between particles and the shield machine, and the energy density between particles and the shield machine.

9. The mechanical simulation method of the cutter head of the earth pressure balance shield machine during tunneling according to any one of claims 1-8, characterized in that, The discrete element software is EDEM software.

10. The mechanical simulation method of the cutter head of an earth pressure balance shield machine during tunneling according to claim 9, characterized in that, The finite element software is ABAQUS software.

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