A method for configuring a shield cutter for soft flow plastic strata

Abstract

This invention relates to a method for configuring cutterhead cutters in soft plastic strata, belonging to the field of shield tunneling technology. The method includes: determining the selection of cutterhead cutters based on stratum characteristics, construction environment, and engineering requirements; determining the layout design of the selected cutters based on the special characteristics of the stratum and the distribution characteristics of the pile foundation; and quantifying the remaining lifespan and replacement cycle of each cutter on the cutterhead using a constructed cutter wear prediction model. Specifically, when selecting the cutterhead, one or more continuous annular ribs are configured between the main and auxiliary spokes. These continuous annular ribs have a first included angle that allows the cutting reaction force to be uniformly transmitted to the main spoke when under stress, and a second included angle that ensures the continuity of the excavated soil flow path. The rib plates of the continuous annular ribs are constructed as a tortuous structure with at least two bends to reduce cutter wear during construction in soft plastic strata.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) construction technology, and in particular to a method for configuring cutterheads in TBMs operating in soft fluid plastic strata. Background Technology

[0002] Soft plastic strata, due to their high water content, low strength, and high fluidity, have long been considered complex working conditions in tunnel boring machine (TBM) construction. During excavation, these strata are prone to mud cake accumulation due to poor excavation fluidity, leading to decreased cutterhead cutting efficiency, blockage of the muck discharge channel, and even affecting the overall tunneling speed of the TBM. To address this challenge, existing technologies generally employ composite cutterhead structures, combining the high opening ratio of spoked cutterheads with the local support advantages of panel cutterheads to optimize the muck discharge path and improve cutterhead stability. However, the continuous grinding requirements for large-diameter reinforced concrete pile groups in soft plastic strata further exacerbate the construction difficulty. The cutters must be able to cut reinforced concrete with high strength while also adapting to highly viscous muck, placing higher demands on cutterhead structure design and cutter configuration.

[0003] CN115030734A discloses a method for configuring cutterhead tools for shield tunneling of large-diameter reinforced concrete pile foundations, including: a planar "three-zone cutter" configuration: the "three-zone cutter" is divided from the inside to the outside into a "central zone", a "main grinding zone" and a "main damage zone"; the "central zone" is configured with a central double-tear cutter, the "main grinding zone" is configured with a front tear cutter, and the "main damage zone" is configured with a hobbing cutter and a welded tear cutter; a height-based "three-layer cutter" configuration: the "three-layer cutter" is divided from high to low into a "main cutting layer", a "secondary cutting layer" and a "scraping layer"; the "main cutting layer" includes a main tear cutter and a hobbing cutter, the main tear cutter includes a central double-tear cutter and a front tear cutter, with a cutter height of H1; the "secondary cutting layer" includes an auxiliary tear cutter, i.e., a welded tear cutter, with a cutter height of H2; the "scraping layer" includes a scraper, with a cutter height of H3, and H1 > H2 > H3.

[0004] While composite cutterheads have improved slag removal performance to some extent, existing technologies still present several unresolved issues. For example, traditional cutterhead rib designs struggle to dynamically screen slag particles, leading to the accumulation of large particles in critical areas, resulting in increased cutter wear and a higher risk of mud cake formation. Furthermore, the unevenness of the cutterhead torque transmission path can cause localized stress concentration, accelerating structural fatigue damage and shortening cutterhead lifespan. Simultaneously, the wear patterns of cutters in soft plastic strata are complex, and the wear of the surface weld overlay and the spalling of alloy materials are difficult to quantify accurately using existing predictive models, resulting in a lack of scientific basis for cutter replacement strategies. These problems not only affect the continuity of tunnel boring machine (TBM) construction but also significantly increase maintenance costs and engineering risks.

[0005] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention provides a method for configuring cutterheads in soft fluid plastic formations to solve at least some of the above-mentioned technical problems.

[0007] This invention discloses a method for configuring cutterhead cutters in soft plastic strata, comprising the following steps: determining the selection of cutterhead cutters based on stratum characteristics, construction environment, and engineering requirements; determining the layout design of the selected cutters based on the special characteristics of the stratum and the distribution characteristics of the pile foundation; and quantifying the remaining life and replacement cycle of each cutter on the cutterhead by constructing a cutter wear prediction model. When selecting the cutterhead, one or more continuous annular ribs are configured between the main and auxiliary spokes. These continuous annular ribs include a high section connected to the main spoke, a low section connected to the auxiliary spoke, and a transition section connecting the two. A first angle is formed between the high section and the transition section, enabling the continuous annular rib to uniformly transmit the cutting reaction force to the main spoke when under stress. A second angle is formed between the low section and the transition section to ensure the continuity of the soil flow path. This results in the continuous annular rib plates being constructed as a tortuous structure with at least two bends, reducing cutter wear during construction in soft plastic strata and thus improving the prediction quality for cutter wear.

[0008] This invention reduces tool wear during soft plastic formation construction by configuring continuous annular ribs between the main and auxiliary spokes of the cutterhead. The continuous annular ribs form a rib plate with a specific tortuous structure through multiple specific bends (such as the first angle between the high section and the transition section, and the second angle between the low section and the transition section). By optimizing the torque transmission path, the cutting reaction force is evenly distributed along the path of the main spoke, the high connection point, the intermediate curved section, the low connection point, and the auxiliary spoke, thereby reducing cutterhead vibration and fatigue damage caused by local stress concentration. This uniform torque transmission reduces the risk of abnormal tool wear due to asymmetric loads. Simultaneously, the tapered cross-section design of the continuous annular ribs (such as wide inlet and narrow outlet) uses a dynamic screening mechanism to retain large particles of excavated soil in the wide cross-section area, reducing their direct impact on the tool, while fine particles of excavated soil are guided to the central opening of the cutterhead by centrifugal force, reducing the probability of cake formation. This structural design not only improves the excavation efficiency but also reduces the contact frequency between the tool and highly viscous excavated soil, thereby extending tool life. Furthermore, the reinforcing rib structure and wear-resistant alloy coating (such as tungsten carbide alloy) at the high connection point further disperse the stress concentration at the connection between the main spoke arm and the annular rib, avoiding structural failure caused by local wear, providing a more stable monitoring environment for the tool wear prediction model, and improving the prediction accuracy.

[0009] According to a preferred embodiment, the high section of the continuous annular rib is connected to the main spoke arm via a high connection point, and the low section is connected to the secondary spoke arm via a low connection point. The connection between the high connection point and the main spoke arm adopts a reinforcing rib structure and is covered with a wear-resistant alloy coating. The connection between the low connection point and the secondary spoke arm adopts an arc transition design and is covered with a wear-resistant coating. The angles of the first included angle and the second included angle of the continuous annular rib are designed to complement each other so that the high connection point and the low connection point of the continuous annular rib have different axial heights.

[0010] This invention optimizes the stability of the cutter head structure and the controllability of tool wear by designing preset angles for the high, low, and transition sections of the continuous annular ribs, combined with the reinforcing rib structure and wear-resistant coating at the high connection point, and the arc-shaped transition design at the low connection point. The angle between the high section and the transition section (e.g., 60°) ensures that the cutting reaction force is efficiently transmitted through the main spoke arm, avoiding uneven stress distribution caused by angular deviations; while the angle between the low section and the transition section (e.g., 120°) together with the angle of the high connection point forms a 180° symmetry, making the flow path of the slag continuous and smooth, reducing the additional wear of the tool due to flow resistance. The triangular or trapezoidal reinforcing ribs at the high connection point are fixed by welding or high-strength bolts, effectively dispersing the shear stress at the connection between the main spoke arm and the annular rib, reducing the risk of fatigue crack propagation caused by local stress concentration. At the same time, the wear-resistant coating (e.g., tungsten carbide alloy) on the surface of the high connection point resists the erosion of highly viscous slag in soft plastic strata, extending the service life of the connection part. The low-connection-point arc transition design (5mm fillet radius) reduces stress concentration at the connection between the secondary spoke arm and the annular rib through geometric optimization. Meanwhile, the wear-resistant coating (such as chromium carbide alloy) has its hardness adjusted to suit the lower load-bearing capacity of the secondary spoke arm, satisfying wear resistance requirements while avoiding brittle fracture due to over-hardening. These designs collectively improve the overall stiffness and fatigue resistance of the cutter head, providing more stable mechanical boundary conditions for the tool wear prediction model, thereby enhancing the reliability of the prediction results.

[0011] According to a preferred embodiment, the transition section is configured as a transition curve, with the high section near the high connection point having a relatively wider cross-section. The transition curve gradually contracts towards the low connection point after passing through the transition section to form a tapered structure. The continuous annular rib achieves dynamic screening of the slag particle size through cross-sectional changes. The surface of the transition curve is covered with a wear-resistant coating to optimize the smoothness of slag flow and disperse stress.

[0012] This invention achieves dynamic screening of slag particle size through a gradually narrowing curve design (such as a circular arc or parabola) and cross-sectional changes in the transition section, solving the problem of abnormal cutter wear caused by large slag particles clogging critical areas of the cutterhead in soft plastic strata. The transition section near the high connection point has a wider cross-section (e.g., 80mm), gradually narrowing towards the low connection point (e.g., 53mm), forming a "wide in, narrow out" gradually narrowing structure. This design utilizes the principle of inertia to retain large slag particles (such as concrete fragments) in the wide cross-sectional area, while small slag particles (such as mud) enter subsequent channels through cross-sectional contraction, significantly reducing the direct impact and friction of large particles on the cutterhead. The smoothness of the transition curve (e.g., a circular arc with a radius of curvature of 70mm or a parabola with a curvature coefficient of 0.8) optimizes the continuity of slag flow, reducing the additional wear on the cutterhead due to flow resistance. Furthermore, the wear-resistant coating (such as silicon carbide alloy) on the surface of the transition curve disperses stress through a hardness gradient design (lower than the coating hardness at the connection point), avoiding cutterhead surface damage caused by brittle fracture of the coating. This dynamic screening and flow optimization mechanism not only improves slag discharge efficiency but also reduces the contact area between the cutting tool and the highly viscous slag, thereby extending the tool life and providing more stable slag flow parameters for the wear prediction model, thus improving prediction accuracy.

[0013] According to a preferred embodiment, in the selection of cutterhead cutters, the cutter type adaptability design is tailored to the characteristics of soft plastic strata and reinforced concrete pile groups. The core combination is a roller cutter and a tearing cutter. The roller cutter controls the excavation diameter by rolling and breaking the concrete, while the tearing cutter cuts the reinforcing steel by punching and shearing the concrete. The two work together, and auxiliary cutters, including scrapers and / or shell cutters, are provided to meet the needs of scraping the excavated soil and secondary cutting of the reinforcing steel.

[0014] This invention addresses the problems of low crushing efficiency and high tool wear rate in reinforced concrete piles in soft plastic strata through the synergistic design of a roller cutter and a tearing cutter. The roller cutter controls the excavation diameter through a rolling crushing mechanism, and its high rigidity design results in uniform wear primarily on the surface weld layer during concrete crushing. The tearing cutter cuts the reinforcing steel through a punching and shearing mechanism, and its multi-alloy blade tip design significantly improves the steel cutting capability and reduces the risk of single-point wear. The combination of the roller cutter and tearing cutter, through functional complementarity, allows the tools to effectively cut the reinforcing steel while crushing concrete, avoiding abnormal tool wear caused by residual reinforcing steel. The configuration of auxiliary tools (such as scrapers and shell cutters) further optimizes the cutting process: scrapers reduce the difficulty of cutting the reinforcing steel by scraping away the concrete protective layer, while the large alloy design of the shell cutter enhances wear resistance, adapting to the frequent tool wear scenarios in soft plastic strata. This tool type adaptability design, through functional zoning and material optimization, reduces the overall tool wear rate and provides a clearer correlation between tool type and wear mode for the wear prediction model, thereby improving prediction accuracy.

[0015] According to a preferred embodiment, the arrangement of the cutter head tools follows the dual principles of functional zoning and hierarchical layering. The cutter head layout is divided into inner ring area, middle ring area and outer ring area corresponding to different cutting tasks and wear characteristics. A layered cutting strategy is formed by gradually decreasing the tool height to deal with the complex structure of reinforced concrete piles.

[0016] This invention solves the problem of uneven tool wear caused by the complex structure of reinforced concrete piles in soft plastic strata by using a functional zoning of the inner, middle, and outer rings of the cutterhead layout and a layered cutting strategy. The inner ring area is equipped with dual tearing cutters to handle slag removal and preliminary cutting. Its larger cutter spacing (adapting to slight wear at low linear velocities) reduces the number of cutters and construction costs, while auxiliary slag removal devices (such as foam injection nozzles) reduce the erosion of the cutters by mud cake formation. The middle ring area, as the cutting core, uses a dynamic cutter spacing design for the front tearing cutters (adjusted according to cutting intensity) to ensure uniform tool stress and avoid abnormal wear caused by localized overload. The outer ring area achieves diameter maintenance through a high-density arrangement (small cutter spacing) of roller cutters and welded tearing cutters, and utilizes the high rigidity and impact resistance of the roller cutters to reduce the risk of tool breakage due to high linear velocities. The layered cutting strategy, through the height difference design of the main layer, auxiliary layer, and terminal layer (e.g., 160mm for the main tearing cutter and 115mm for the scraper), distributes the cutting force layer by layer, reducing the stress peak of a single cutter. This collaborative design of partitioning and layering not only optimizes the tool wear distribution but also provides clearer regional wear characteristics for the wear prediction model, thereby improving the spatial resolution and dynamic adjustment capability of the prediction model.

[0017] According to a preferred embodiment, the inner ring region undertakes the functions of slag removal and preliminary cutting, is equipped with a double tearing cutter and an auxiliary slag removal device, and has a relatively larger cutter spacing; the middle ring region is the core cutting region, equipped with a front tearing cutter, and the cutter spacing is dynamically adjusted according to the cutting intensity; the outer ring region is mainly for diameter protection and safety reserve, equipped with a combination of hobbing cutter and welded tearing cutter, and has a relatively smaller cutter spacing to improve tool density.

[0018] This invention addresses the problems of uneven tool wear distribution and low slag removal efficiency in soft plastic formations by employing differentiated tool configurations and tool spacing designs in the inner, middle, and outer ring regions. In the inner ring region, the double-layered tearing cutter, due to its lower linear velocity and larger tool spacing, experiences a slower wear rate, and auxiliary slag removal devices (such as foam injection nozzles) effectively reduce the erosion of the cutter by mud cake accumulation. In the middle ring region, the frontal tearing cutter optimizes stress uniformity through dynamic tool spacing adjustment (matched to cutting strength), preventing tool failure caused by localized overload. In the outer ring region, the combination of a roller cutter and a welded tearing cutter enhances diameter retention through a high-density tool spacing (e.g., 27~79mm), while the high rigidity design of the roller cutter reduces the risk of tool breakage due to high linear velocity. This graded tool spacing design, combined with functional area division, ensures a more balanced wear rate for the cutter under different trajectory radii, while improving the continuity of the slag removal channel and reducing abnormal contact between the cutter and the slag. This configuration strategy provides more accurate tool distribution parameters for the wear prediction model, thereby optimizing the spatiotemporal matching of the tool replacement strategy.

[0019] According to a preferred embodiment, in the layered cutting strategy, the cutting tool is divided into a main layer, an auxiliary layer and a terminal layer, with the height of each layer decreasing progressively. The main layer cutting tool first contacts the pile body and is responsible for crushing and initial cutting. The auxiliary layer is replaced after the main layer wears out. The terminal layer is responsible for stripping the concrete protective layer of the reinforcing steel and removing the reinforcing steel. The cutting force is dispersed by the height difference design, reducing abnormal wear of the cutting tool.

[0020] This invention addresses the problems of sudden tool wear failure and low layered cutting efficiency in soft plastic strata by employing a height difference design between the primary layer, auxiliary layer, and terminal layer. The primary layer tools (such as tearing cutters and roller cutters) first contact the pile body, undertaking the tasks of concrete breaking and rebar cutting. Their relatively high tool height (e.g., 160mm) ensures the continuity of the cutting path before the intervention of the auxiliary layer. The auxiliary layer tools (such as welded tearing cutters) participate in cutting after the primary layer wears to a critical value. Their height difference design (e.g., 140mm) avoids redundant wear due to premature contact and achieves a smooth transition of cutting capability by gradually increasing participation. The terminal layer tools (such as scrapers) peel away the concrete protective layer of rebar with the lowest tool height (e.g., 115mm), creating conditions for rebar separation and removal. This height difference design significantly reduces the peak stress of a single tool by dispersing the cutting force layer by layer, extending the life of the primary layer tools. Furthermore, the incremental logic of the layered cutting strategy provides a clear tool function switching threshold for the wear prediction model, thereby improving the model's dynamic response to tool replacement timing.

[0021] According to a preferred embodiment, in the wear monitoring and prediction of cutting tools, the wear forms of cutting tools include wear of the surface weld overlay and spalling of alloy materials. One or more of the following data are collected through multi-dimensional sensors and manual inspection and substituted into the prediction model for calculation: trajectory radius, cutting tool type, cutting head rotation direction, push speed and rotation speed, and pile foundation distribution pattern.

[0022] This invention addresses the complexity and difficulty in quantifying tool wear patterns in soft plastic formations by collecting tool wear-related data through multi-dimensional sensors and manual inspection. Tool wear is comprehensively influenced by the trajectory radius, tool type, cutterhead rotation direction, feed rate to rotation speed ratio, and pile foundation distribution patterns. For example, an increased trajectory radius leads to increased tool linear velocity and impact force, accelerating wear of the surface weld overlay and alloy material spalling. Differences in cutterhead rotation direction (uneven wear between the tangential and reverse surfaces) require correction of model parameters through monitoring data. By real-time acquisition of tool trajectory radius, feed rate, rotation speed, cumulative cutting revolutions, and pile foundation geometric parameters, the relationship between the wear coefficient (k) and remaining life (L) can be quantified, thereby dynamically adjusting the prediction model. This data-driven monitoring method provides more comprehensive input variables for the wear prediction model, significantly improving the model's adaptability to tool wear trends and prediction accuracy.

[0023] According to a preferred embodiment, the tool wear prediction model predicts the remaining life by calculating the cutting length and combining the wear amount and wear coefficient. The cutting length calculation formula includes two cases: cutting through the pile foundation and not cutting through the pile foundation. The remaining allowable wear amount and the remaining cutting length are determined based on the current wear amount and the critical wear amount.

[0024] This invention solves the problem of difficulty in modeling the nonlinear relationship between tool wear and cutting length in soft plastic strata by using a cutting length calculation formula (distinguishing between fully penetrated and partially penetrated pile foundations) and a wear coefficient (k) to predict remaining life. The cutting length formula, combined with the cutterhead trajectory radius, pile cutting time, and angle correction coefficient, accurately quantifies the actual cutting path of the tool. The wear coefficient (k) is dynamically corrected using field monitoring data (such as the reduction in weld overlay thickness), reflecting the combined influence of tool material, type, and construction parameters. Current wear amount (δ) current ) and critical wear (δ) max The comparison further clarifies the remaining allowable wear and remaining cutting length (L), providing a quantitative basis for tool replacement decisions. This prediction method based on a physical model significantly improves the interpretability and engineering applicability of tool life prediction through the linear relationship between cutting length and wear.

[0025] According to a preferred embodiment, the tool replacement decision is dynamically adjusted based on wear prediction results and construction progress. In this embodiment, the design of the composite cutter head opening ratio and the continuous annular rib torque transmission optimization are combined, and different replacement cycles are set considering the differences in wear coefficients of different tool types. The wear difference between the positive and negative cutting surfaces is balanced by adjusting the rotation direction of the cutter head.

[0026] This invention resolves the contradiction between uncontrollable cutter wear and low construction efficiency in soft plastic strata by dynamically adjusting cutter replacement decisions in conjunction with tunnel boring machine (TBM) construction parameters. Based on wear prediction results and dynamic adjustments to the construction schedule, priority is given to ensuring slag removal efficiency under the 35% opening ratio design of the composite cutterhead. For example, when the wear of the main layer tearing cutter exceeds 15%, the decision to replace it prematurely is made based on opening ratio monitoring data. Different replacement cycles are set for the wear coefficient differences between the outer ring area roller cutter and the welded tearing cutter to ensure that diameter preservation is prioritized. Adjusting the cutterhead rotation direction to balance the wear difference between the forward and reverse surfaces (e.g., counterclockwise rotation intensifies wear on the reverse surface, switching to clockwise rotation) further extends cutter life. This dynamic decision-making mechanism, through real-time feedback from the wear prediction model and construction parameters, significantly improves the scientific nature of the cutter replacement strategy and the continuity of construction. Attached Figure Description

[0027] Figure 1 This is a flowchart of the steps for configuring the cutterhead of a tunnel boring machine in soft fluid plastic strata provided by the present invention;

[0028] Figure 2 This is a schematic diagram of the selection and arrangement of cutter heads and cutting tools provided by the present invention;

[0029] Figure 3 This is a schematic diagram showing the arrangement of the continuous annular ribs provided by the present invention;

[0030] Figure 4 This is a schematic diagram of the continuous annular rib structure provided by the present invention.

[0031] List of reference numerals

[0032] 100: Main spoke arm; 200: Secondary spoke arm; 300: Continuous annular rib; 310: High section; 311: High connection point; 320: Low section; 321: Low connection point; 330: Transition section; 400: Outer ring area; 500: Middle ring area; 600: Inner ring area; α: First included angle; β: Second included angle. Detailed Implementation

[0033] The following is a detailed explanation with reference to the accompanying drawings.

[0034] like Figure 1 As shown, this invention discloses a method for configuring cutterheads in a shield tunneling machine in soft fluid plastic formations, comprising:

[0035] S1. Selection of cutterhead and cutting tools: The selection of cutterhead and cutting tools is determined based on the geological characteristics, construction environment and engineering requirements;

[0036] S2. Cutterhead tool arrangement: The layout design of the selected tools is determined based on the special characteristics of the strata and the distribution characteristics of the pile foundation.

[0037] S3. Tool Wear Monitoring and Prediction: By constructing a tool wear prediction model, the remaining life and replacement cycle of each tool arranged on the tool turret are quantified.

[0038] Preferably, when conducting shield tunneling in soft plastic strata, the selection of cutterhead tools can be determined based on stratum characteristics, construction environment, and engineering requirements to achieve efficient tunneling, reduce tool wear, and ensure construction safety. Soft plastic strata typically have characteristics of high water content, low strength, easy flow, and easy mud cake formation, and the construction process must address the challenge of continuous grinding of large-diameter reinforced concrete pile groups. Therefore, the selection process for cutterhead tools mainly includes: selection of cutterhead structure, adaptability design of tool types, and optimization of wear resistance and impact resistance.

[0039] Preferably, the selection of cutterhead structure should prioritize its adaptability to soft plastic strata. Specifically, when conducting shield tunneling in soft plastic strata, a "composite cutterhead" is the preferred choice. The composite cutterhead combines the advantages of spoked and panel cutterheads, ensuring smooth excavation through a high opening ratio (approximately 35%) while enhancing the stability of the cutterhead in soft plastic strata through the local support of the panel. In soft plastic strata, high water content and low strength can lead to poor excavation flowability. If the cutterhead opening ratio is insufficient, excavation can easily accumulate in the soil chamber, forming mud cakes, which in turn affects the cutting efficiency of the cutterhead and the tunneling speed of the shield machine. Therefore, the composite cutterhead, by optimizing the balance between the opening ratio and the panel support, ensures efficient excavation discharge while reducing the risk of mud cake formation.

[0040] Preferably, such as Figures 2-4As shown, the cutterhead may include several main spokes 100 and secondary spokes 200. One or more continuous annular ribs 300 may be configured between the main spokes 100 and the secondary spokes 200 to achieve dynamic screening of excavated soil flow, uniform torque transmission, and improved stability of the cutterhead structure through the synergistic effect of height difference connection points, tapered cross-section design, and multi-angle bending forms. The continuous annular ribs 300 can achieve uniform torque transmission, optimized guidance of excavated soil flow, and improved overall stiffness of the cutterhead through differentiated anchoring of the main spokes 100 and secondary spokes 200, combined with a tortuous structure at specific geometric angles. Preferably, the continuous annular ribs 300 may have connection points on both sides at unequal heights, with one side connected to the main spokes 100 and the other side connected to the secondary spokes 200. Furthermore, the continuous annular rib 300 can be connected to the main spoke arm 100 through a high connection point 311 and to the secondary spoke arm 200 through a low connection point 321, forming a rib plate between the high connection point 311 and the low connection point 321. The rib plate can employ a tapered cross-section design. The angle optimization and reinforcing rib design of the continuous annular rib 300 can achieve stress dispersion and extended fatigue life. This design is particularly critical in soft plastic formations because it can reduce large-particle soil blockage through a dynamic screening mechanism, while simultaneously using centrifugal force to guide fine-particle soil towards the center opening of the cutterhead, reducing the risk of cake formation.

[0041] Preferably, such as Figure 3 and Figure 4 As shown, the continuous annular rib 300 may include a high section 310 with a high connection point 311 connected to the main spoke arm 100, a low section 320 with a low connection point 321 connected to the secondary spoke arm 200, and a transition section 330 connected to both the high section 310 and the low section 320. The high connection point 311 is fixed to the main spoke arm 100 of the cutter head. As the core load-bearing structure of the cutter head, the main spoke arm 100 has higher rigidity and strength and can bear the main cutting torque and propulsion reaction force. The first included angle α between the high section 310 and the transition section 330 is designed to be selectable within the range of 50°~70°, preferably 60°. This angle setting allows the continuous annular rib 300 to uniformly transmit the cutting reaction force to the main spoke arm 100 when under stress, avoiding local stress concentration. The connection between the high connection point 311 and the main spoke arm 100 can be reinforced with triangular or trapezoidal ribs, which are fixed by welding or high-strength bolts. The cross-sectional height of the ribs can be selected from 8 to 15 mm, preferably 12 mm, to disperse stress concentration and improve connection reliability. In addition, the surface of the high connection point 311 can be covered with a wear-resistant alloy coating (such as tungsten carbide alloy), with a thickness of 1.5 to 3 mm, preferably 2 mm, to resist the erosion of highly viscous soil in soft plastic strata.

[0042] Preferably, such as Figure 3 and Figure 4As shown, the low connection point 321 is anchored to the secondary spoke arm 200 of the cutterhead. The secondary spoke arm 200 serves as an auxiliary support structure, bearing secondary loads. The second included angle β between the low section 320 and the transition section 330 is designed to be within the range of 110°~130°, preferably 120°, forming a 180° symmetry with the angle of the high connection point 311, ensuring the continuity of the slag flow path. The connection between the low connection point 321 and the secondary spoke arm 200 adopts an arc-shaped transition design, with a fillet radius of 4~8mm, preferably 5mm, to reduce the risk of stress concentration. The surface of this connection point is also covered with a wear-resistant coating, with the same thickness as the high connection point 311. However, because the load-bearing capacity of the secondary spoke arm 200 is lower, the wear resistance of the coating can be appropriately reduced (e.g., chromium carbide alloy can be selected).

[0043] Preferably, such as Figure 3 and Figure 4 As shown, the transition section 330 can be configured as a transition curve, connecting to the high section 310 and the low section 320 on both sides respectively. The high section 310, near the high connection point 311, has a wider cross-section, gradually narrowing towards the low connection point 321, forming a "wide in, narrow out" tapering structure. The width ratio is designed to be selectable from 1.3:1 to 1.7:1, preferably 1.5:1. For example, if the cross-sectional width at the high connection point 311 is 80mm, the width at the low connection point 321 can be set to 53mm. The dynamic screening function of the slag particle size is achieved through the cross-sectional change: large slag particles (such as concrete fragments) are retained in the wide cross-sectional area due to inertia, while small slag particles (such as mud) enter the subsequent channel as the cross-section shrinks. The transition curve of transition section 330 can be designed as a circular arc or a parabola. The radius of curvature of the circular arc can be selected from 50 to 100 mm, preferably 70 mm, to optimize the smoothness of the slag flow; the coefficient of curvature of the parabola can be selected from 0.5 to 1.2, preferably 0.8, to balance the flow velocity and stress distribution. The surface of the transition curve is covered with a wear-resistant coating with the same thickness as the connection point. However, because the impact force is relatively small, the hardness of the coating can be slightly lower than that of the connection point (e.g., silicon carbide alloy can be selected).

[0044] Regarding the dynamic screening mechanism, the synergistic effect of the tapered cross-section of the continuous annular rib 300 and the wear-resistant coating allows large particles of excavated soil to be retained in the wide cross-section area, reducing the risk of blockage. In terms of torque transmission uniformity, the angle-optimized continuous annular rib 300 structure ensures that the cutting reaction force is uniformly transmitted along the path of the main spoke arm 100, high connection point 311, intermediate curved section, low connection point 321, and secondary spoke arm 200, reducing cutterhead vibration and local fatigue damage. Regarding excavated soil flowability optimization, the combination of the transition curve and velocity gradient utilizes centrifugal force to guide the excavated soil towards the central opening of the cutterhead, effectively suppressing cake formation. Furthermore, the reinforcing rib design at the high connection point 311 and the arc-shaped transition at the low connection point 321 further enhance the overall stability of the structure, enabling it to maintain efficient excavation and stable tunneling capabilities for extended periods in soft plastic strata with high water content and low strength.

[0045] Preferably, the adaptability design of the cutting tool type can be specifically selected based on the characteristics of soft plastic strata and reinforced concrete pile groups. In soft plastic strata, the cutting tool must not only meet the cutting requirements of high-viscosity strata but also take into account the grinding capability of reinforced concrete pile foundations. Among these, the core combination of cutting tool selection is roller cutter and tearing cutter. The roller cutter controls the excavation diameter through the mechanism of rolling and crushing concrete, and is suitable for crushing concrete, but its cutting capability for steel bars is relatively weak. The tearing cutter, on the other hand, can effectively cut steel bars through the mechanism of punching and shearing concrete and cutting steel bars, achieving efficient cutting of reinforced concrete piles. The two work together to ensure the crushing efficiency of pile concrete and reduce the risk of steel bar wear on the cutting tool. In addition, the cutting tool can also be equipped with auxiliary cutting tools such as scraper and shell cutter to meet the scraping requirements of slag in soft plastic strata and the secondary cutting of pile foundation steel bars. For example, the scraper reduces the difficulty of cutting steel bars by scraping off the concrete protective layer; the shell cutter enhances wear resistance through a large alloy design, adapting to the frequent cutting tool wear scenarios in soft plastic strata. The selection of cutting tools can also take into account the matching between their installation position and trajectory radius. For example, edge roller cutters can preferentially contact the pile foundation and create conditions for the tearing blade to cut the reinforcing bar by breaking the outer concrete, while the center double tearing blade optimizes the stress distribution and reduces stress concentration by eliminating the fishtail center blade design.

[0046] Preferably, optimizing the wear resistance and impact resistance of the cutting tools is crucial for ensuring continuous tunneling of the shield. In soft plastic strata, cutting tools are prone to severe wear due to mud cake adhesion, concrete breakage, and steel bar impact when cutting high water-bearing strata and reinforced concrete pile foundations. To address this, the cutting tools can be alloyed, for example, with the cutter ring inlaid with carbide teeth and the tearing cutter tip equipped with multiple alloy blocks to improve their wear resistance and impact resistance. Simultaneously, a wear-resistant weld layer can be installed on the back of the cutter holder to prevent the cutting tools from detaching or breaking under frequent impacts. Furthermore, the cutter height difference design can be precisely controlled. For example, the height difference between the main tearing cutter (160mm) and the scraper (115mm) can meet the scraping requirements of the steel bar protective layer, while the auxiliary tearing cutter (140mm) can maintain a distance from the scraper not less than the steel bar diameter (25mm) to avoid damage to the scraper due to excessive force. This tool height difference design is particularly critical in soft plastic formations because it can reduce the damage to a single tool and extend tool life through layered cutting.

[0047] Preferably, when conducting shield tunneling for large-diameter reinforced concrete pile foundations in soft plastic strata, the cutter layout design can be determined based on the specific characteristics of the strata and the distribution features of the piles to achieve efficient cutting and balanced wear. To address this need, the cutter configuration can follow a dual principle of functional zoning and hierarchical layering. By scientifically dividing the functional areas and height levels of the cutters, cutting efficiency can be optimized and cutter life extended. Specifically, the cutterhead layout can be divided into three functional areas, corresponding to different cutting tasks and wear characteristics. Simultaneously, a layered cutting strategy is formed through a progressively decreasing cutter height design to cope with the complex structure of the reinforced concrete piles.

[0048] Preferably, such as Figure 2 As shown, in terms of functional zoning, the layout of the tool turret can be divided according to the distribution characteristics of the trajectory radius.

[0049] Preferably, the inner ring region 600 primarily performs slag removal and preliminary cutting functions. The cutting tools in this region possess high rigidity and wear resistance to address the high water content and low strength characteristics of soft plastic strata. In this region, a double-layered tearing cutter is the core component, designed to balance slag removal efficiency with preliminary crushing capability of the pile concrete. Due to the lower linear velocity in the inner ring region 600, tool wear is relatively less, allowing for a more significant increase in the cutter spacing to reduce the number of cutters and lower construction costs. Furthermore, the inner ring region 600 can also be equipped with auxiliary slag removal devices, such as foam spray nozzles or water flushing systems, to prevent slag accumulation leading to mud cake formation, which could affect the normal operation of the cutterhead.

[0050] Preferably, the middle ring region 500 is the core area for the cutting task, requiring tools capable of efficiently breaking concrete and cutting reinforcing bars. The tools in this region should possess strong shearing and impact resistance to meet the high-intensity cutting requirements of reinforced concrete piles. A front-facing tearing blade, as the primary configuration, can incorporate multiple alloy pieces in its tip design to enhance cutting ability and reduce wear. Simultaneously, the blade spacing in the middle ring region 500 can be dynamically adjusted according to the cutting intensity, ensuring uniform force on the tools during cutting and preventing tool failure due to localized overload. Furthermore, the tool layout in the middle ring region 500 can synergize with that in the inner ring region 600, achieving gradual concrete breaking and segmented cutting of reinforcing bars through a rational tool arrangement.

[0051] Preferably, the outer ring region 400 primarily functions as a diameter-maintaining and safety reserve area, and can be configured with a combination of roller cutters and welded tearing cutters. The roller cutter crushes concrete through rolling action while controlling the excavation diameter, while the welded tearing cutter serves as a redundant configuration, providing cutting support in case the roller cutter wears or is damaged. The co-trajectory arrangement of both ensures the continuity of the cutting path, and the high rigidity and impact resistance of the roller cutter reduce the risk of tool breakage due to high linear velocities in the outer ring region 400. Furthermore, the cutter spacing in the outer ring region 400 can be further reduced to increase tool density, enhance diameter-maintaining capability, and reduce the cumulative effect of pile damage. This design is particularly important in soft plastic formations, as it can disperse cutting forces through a high-density tool arrangement, avoiding localized stress concentration and thus extending tool life.

[0052] Preferably, in terms of the layered cutting strategy, the height difference design of the cutting tools is key to achieving functional synergy. By dividing the cutting tools into a primary layer, an auxiliary layer, and a secondary layer, the height of the cutting tools in each layer decreases progressively, forming a staged cutting path. The cutting tools in the primary layer (such as tearing cutters and hobs) first contact the pile body, responsible for breaking up the concrete and initially cutting the reinforcing steel; the cutting tools in the auxiliary layer (such as welded tearing cutters) then take over the cutting after the primary layer wears out, providing a safety reserve; the cutting tools in the secondary layer (such as scrapers) are responsible for stripping the concrete cover of the reinforcing steel and removing it after the reinforcing steel is cut into short sections. This layered design not only reduces the wear of a single cutting tool but also reduces the risk of abnormal tool wear by dispersing the cutting force through layer-by-layer cutting.

[0053] Preferably, the cutting tools in the primary layer, due to their priority contact with the pile body, need to possess strong impact rock-breaking capabilities and wear resistance. For example, tearing blades cut reinforcing bars through shearing action, while rolling blades crush concrete through rolling. Their height should be slightly higher than that of the auxiliary layer to ensure that the auxiliary layer does not prematurely intervene in the cutting path before the primary layer is fully worn. The cutting tools in the auxiliary layer, as the second tier, gradually assume cutting tasks after the primary layer has worn to a certain extent. Their height difference needs to maintain a reasonable distance from the primary layer, avoiding redundant wear due to premature contact while promptly supplementing the cutting capacity of the primary layer. The cutting tools in the terminal layer primarily function to scrape and clean, and have the lowest height. By peeling away the concrete protective layer of reinforcing bars layer by layer, they create conditions for the segmentation and removal of the reinforcing bars. This layered design, through the gradual decrease in height difference, achieves a relay transfer of cutting function, extending the service life of the primary layer cutting tools while ensuring the effective participation of the auxiliary and terminal layers in the cutting process. Furthermore, the stepped layout optimizes the stress distribution on the cutting tools. In soft plastic strata, the fracturing of pile concrete and the cutting of reinforcing steel can easily lead to localized stress concentration. If all cutting tools are at the same height, uneven stress distribution may cause tool breakage or detachment. However, by designing a height difference between the main layer, auxiliary layer, and terminal layer, the cutting force can be distributed to the cutting tools at different levels, reducing the peak stress of a single tool. For example, the main impact force borne by the cutting tool in the main layer can be shared by the tools in the auxiliary layer, while the tools in the terminal layer further release residual stress through scraping. This synergistic mechanical effect not only improves the overall durability of the cutting tools but also reduces unplanned replacements due to localized overload.

[0054] Preferably, in soft plastic strata, the rational configuration of the cutting tool layout can be optimized in conjunction with the distribution pattern of the pile foundations. For example, in areas with dense pile groups, the coverage area of ​​the cutting tools can be increased to ensure the continuity of the cutting path; for isolated areas with single piles, cutting interference can be reduced by adjusting the spacing and height difference between the cutting tools. Furthermore, the wear-resistant design of the cutting tools can be tailored to local conditions. For instance, in soft plastic strata, the surface of the cutting tools can be coated with a high-wear-resistant alloy to resist the erosion of the cutting tools by the high-viscosity strata. Simultaneously, the installation position of the cutting tools should avoid direct conflict with the reinforcing steel bars in the piles, and the reasonable division of the trajectory radius can reduce tool wear and extend service life.

[0055] Preferably, the adaptability of the layout can be further optimized by dynamically adjusting the tool spacing. In the inner ring region 600, the tool spacing is larger to accommodate lower cutting intensity and wear requirements; in the middle ring region 500, the tool spacing is moderate, ensuring cutting efficiency while balancing the number of tools; and in the outer ring region 400, the tool spacing is smaller to improve diameter preservation and cutting density. This dynamic adjustment strategy can match the cutting requirements of different regions according to changes in the trajectory radius, avoiding local overload or inefficiency caused by unreasonable tool arrangement.

[0056] Preferably, the stepped layout can also be dynamically adjusted in conjunction with tool wear monitoring. For example, when the wear of the main layer tool approaches a critical value, the auxiliary layer tools need to intervene in the cutting path earlier, gradually increasing their participation to ensure the continuity of the cutting task before the main layer tool is replaced. The terminal layer tools need to adjust their scraping frequency according to the thickness of the reinforcing steel cover and the degree of concrete breakage to avoid premature tool wear due to excessive scraping. Through this dynamic layering strategy, the tool wear distribution is more balanced, and cutting efficiency and equipment reliability are improved simultaneously.

[0057] Preferably, in shield tunneling for large-diameter reinforced concrete pile groups in soft plastic strata, cutter wear analysis and prediction are crucial for ensuring construction efficiency and safety. During the cutting process, the cutter is affected by a combination of geological characteristics, pile structure, and construction parameters. Its wear primarily manifests as wear of the surface weld overlay and spalling of alloy materials. Through scientific wear analysis and prediction methods, the remaining lifespan of the cutters can be dynamically assessed, and cutter replacement strategies can be optimized, thereby reducing construction costs and extending equipment lifespan.

[0058] Preferably, based on actual engineering monitoring data, tool wear can be divided into two categories: wear of the surface weld overlay and spalling of the alloy material. Wear of the surface weld overlay is the result of normal friction between the tool and the pile foundation, mainly manifested as a gradual reduction in the thickness of the weld overlay, affecting the tool's cutting efficiency and durability. Spalling of the alloy material, on the other hand, is due to localized damage caused by the impact and shear forces experienced by the tool when cutting reinforcing bars, typically occurring at the tool tip or in areas of concentrated stress. This type of damage is more destructive to the tool, potentially leading to a significant reduction in tool height and even affecting the continuity of the cutting path.

[0059] Preferably, tool wear is influenced by multiple factors, including trajectory radius, tool type, cutter head rotation direction, feed rate and rotational speed, and pile distribution pattern. As the trajectory radius increases, the tool's linear velocity increases, leading to enhanced cutting and impact forces and a significant increase in wear rate. For example, when the trajectory radius exceeds 2500 mm, the tool breakage rate increases sharply, with both the width and thickness of alloy chipping showing an increasing trend. Tool type also significantly affects wear characteristics. Hobs, due to their high rigidity, primarily exhibit uniform wear of the surface weld overlay and are less prone to alloy chipping during cutting. Tear cutters, tasked with cutting tendons, have a much higher alloy chipping rate than hobs, especially in areas with larger trajectory radii, where the breakage at the tool tip can reach over 50% of the tool width. Tool wear is also closely related to the cutter head rotation direction. Since the tool's forward and reverse cutting surfaces alternately contact the pile during cutting, the wear degree differs between the forward cutting surface (the contact surface when the cutter head rotates clockwise) and the reverse cutting surface (the contact surface when the cutter head rotates counterclockwise). Typically, the residual weld overlay on the reverse side is lower, leading to more severe wear. The ratio of feed rate (v) to spindle speed (n) (v / n) determines the cutting frequency and cutting length per unit time. Higher feed rates or spindle speeds result in faster tool wear. For example, an increased feed rate to spindle speed ratio increases the number of times the tool contacts the pile foundation per unit time, significantly increasing the wear of the surface weld overlay. Furthermore, the distribution pattern of the pile foundation (e.g., central piles, near-end side piles, far-end side piles) also affects tool wear. Pile foundations with larger center-to-center distances (e.g., far-end side piles) experience more severe tool wear because their cutting trajectory radius is larger, requiring the tool to withstand higher cutting forces. This differential wear characteristic can be quantified using predictive models to improve prediction accuracy.

[0060] Preferably, based on the above-mentioned influencing factors, this invention constructs a predictive model for tool wear to quantify the remaining life and replacement cycle of the tool. This predictive model requires the collection of several types of data to improve prediction accuracy. These data can be continuously collected through a combination of multi-dimensional sensors and manual inspection to assess tool wear status: Tool trajectory radius (R): The radius of rotation of the tool on the cutterhead (unit: mm), directly affecting cutting force and wear rate; Pushing speed (v): The tunnel boring machine's advancing speed (unit: mm / r), reflecting the speed at which the tool cuts the pile foundation; Rotation speed (n): The cutterhead rotation speed (unit: rpm), which, together with the pushing speed, determines the tool cutting frequency; Cumulative cutting revolutions of the cutterhead (j): The total number of revolutions the tool makes in contact with the pile foundation (dimensionless), used to calculate the cutting length; Pile foundation radius (R pile ): Radius of reinforced concrete pile foundation (unit: mm), affecting the geometric relationship of the cutting path; pile foundation center offset (S) p ): The offset distance (in mm) between the center of the cutterhead trajectory and the center of the pile foundation, used to correct the cutting path.

[0061] Preferably, the prediction model may include the calculation of the cutting length (L) of the tool, and the calculation formula includes the cutting length formula for penetrating the pile foundation and the cutting length formula for not penetrating the pile foundation.

[0062] Preferably, the formula for the cutting length through the pile foundation is as follows:

[0063] ,

[0064] Among them, T i is the cutting time (in seconds) for the i-th pile section, reflecting the actual construction progress; aTC and aTCC are angle correction coefficients (dimensionless), used to adjust the geometric deviations in the tangential and radial directions; r i The radius of the tool path at the i-th cutting position (in mm) must be consistent with the tool turret design parameters.

[0065] Preferably, the formula for the cutting length of the incompletely penetrated pile foundation is as follows:

[0066] ,

[0067] This formula only calculates the tangential displacement and ignores the radial correction term (cos part).

[0068] Furthermore, based on the cutting length (L) and actual wear (δ) of the tool, the wear coefficient (k) can be calculated and the remaining life can be predicted. The formulas between the above three parameters are as follows:

[0069] ,

[0070] Where δ represents the tool wear (unit: mm), obtained through on-site monitoring (e.g., reduction in surface weld overlay thickness); k is the wear coefficient (unit: mm / km), reflecting the combined influence of tool material, type, and construction parameters; and L is the cutting length of the tool (unit: km). This formula shows that the tool wear is linearly related to the cutting length, while the wear coefficient reflects the combined influence of tool material, tool type, and construction parameters.

[0071] Preferably, it is assumed that the current wear of the tool is δ. current Its remaining allowable wear is:

[0072] ,

[0073] Where, δ max This represents the critical wear level of the cutting tool.

[0074] Furthermore, the remaining cutting length can be calculated using the following formula:

[0075] .

[0076] Preferably, the calculation formula for the wear coefficient can be dynamically adjusted based on real-time monitoring data to correct model parameters. For example, when the wear coefficient (k) of the dominant layer tool increases significantly due to the high viscosity of the soft plastic formation, the wear rate can be reduced by increasing the surface alloying treatment of the tool (e.g., cemented carbide tooth density) or adjusting the tool spacing (e.g., reducing the 400-tool spacing in the outer ring region to 27-79 mm). Furthermore, the height difference between the dominant and auxiliary layers designed for the layered cutting strategy (e.g., a main tearing tool height of 160 mm and a scraper tool height of 115 mm) can be optimized through wear coefficient difference analysis to refine the layered replacement logic. For example, when the tool height loss of the dominant layer tool reaches 10%, the auxiliary layer tool needs to intervene in the cutting path earlier, and by gradually increasing its participation, the continuity of the cutting task before the dominant layer tool is replaced can be ensured.

[0077] Preferably, the tool replacement decision can be dynamically adjusted based on wear prediction results and construction progress. According to the design of the composite cutterhead's opening ratio (approximately 35%) and the torque transmission optimization of the continuous annular ribs 300, tool replacement can prioritize ensuring soil removal efficiency and cutting force balance. For example, when the cutter height loss of the main layer tearing cutter exceeds 15%, its slag removal capacity may decrease due to insufficient cutter height; the need for early replacement can be determined by combining opening ratio monitoring data. Furthermore, for the co-trajectory arrangement design of the 400mm roller cutter and welded tearing cutter in the outer ring area, different replacement cycles can be set based on the difference in wear coefficients (e.g., the roller cutter wear coefficient is 7.82mm / km, and the welded tearing cutter wear coefficient is 12.47mm / km). For example, when the remaining cutting length of the 400mm roller cutter in the outer ring area is lower than the current remaining cutting requirements of the pile foundation, the roller cutter can be replaced first to maintain the diameter-keeping function, while the welded tearing cutter is used as a redundant configuration and replaced later.

[0078] Preferably, based on monitoring data of the wear difference between the forward and reverse cutter surfaces (e.g., the residual weld overlay on the reverse surface is lower than that on the forward surface), the wear distribution can be balanced by adjusting the rotation direction of the cutter head. For example, in soft plastic formations, if monitoring shows that the wear rate on the reverse surface increases when rotating counterclockwise, clockwise rotation can be temporarily switched to allow the forward surface to bear more cutting load, thereby extending the tool life. This strategy needs to be combined with optimization of the impact resistance performance of the selected tool (e.g., high rigidity design of hobs) to ensure that the adjustment of the rotation direction will not cause the tool to fall off due to torque fluctuations.

[0079] Preferably, the partitioned design of the tool layout (inner ring, middle ring, outer ring) can increase redundant tool density in areas with severe wear (such as the outer ring region 400 with a trajectory radius of 3457mm). For example, by adding a welded tearing cutter in the middle ring region 500 (main grinding zone), cutting forces can be dispersed and a safety reserve can be provided. In addition, an emergency replacement plan can be developed in conjunction with a stepped layout of the layered cutting strategy. For example, when the main layer tool suddenly fails, the height of the auxiliary layer tool can be reduced (such as temporarily adjusting the height of the welded tearing cutter from 140mm to 130mm) to allow it to quickly enter the cutting path, avoiding the accumulation of pile foundation damage due to tool loss.

[0080] Preferably, dynamic adjustment and cutter replacement decisions can be linked to the tunnel boring machine's construction parameters. For example, when monitoring shows that the cutter wear rate is abnormally high due to the high water content of the soft plastic strata, the foam spraying system parameters can be adjusted simultaneously (e.g., increasing the foam concentration to 30%) to reduce the erosion of the cutters by mud cake adhesion. Furthermore, based on the design of the cutterhead opening ratio and the continuous annular rib 300, the cutter cutting frequency can be controlled by adjusting the ratio of the thrust speed (v) to the rotational speed (n) (v / n). For example, in the early stages of cutter wear (when k is low), the thrust speed can be appropriately increased to accelerate slag removal efficiency; while in the later stages of cutter wear (when k is high), the thrust speed needs to be reduced and the rotational speed increased to disperse the wear load through high-frequency, low-speed cutting.

[0081] Preferably, dynamic adjustment and replacement decisions can feed back into the preceding tool selection and configuration strategies. For example, if monitoring data shows that a certain type of tool (such as a shell cutter) has insufficient wear resistance in soft plastic formations, its alloy coating design can be optimized in subsequent engineering processes, or its position in the cutterhead layout can be adjusted (e.g., moving it from the outer ring region 400 to the inner ring region 600). Furthermore, the design of the height difference between the dominant and auxiliary layers can be validated using a wear prediction model to verify the effectiveness of its layered compensation logic. For example, if monitoring reveals that auxiliary layer tools are experiencing additional wear due to premature intervention in the cutting path, the height difference can be redesigned (e.g., adjusting the auxiliary layer tool height from 140mm to 135mm) to ensure that it only activates when the dominant layer tool wears to a critical value.

[0082] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and do not constitute a limitation on the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; phrases such as "preferred" or "according to a preferred embodiment" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept. Throughout the text, the feature introduced by "preferred" is only an optional mode and should not be construed as mandatory. Therefore, the applicant reserves the right to abandon or delete relevant preferred features at any time.

Claims

1. A method for configuring cutterhead cutters in a shield tunneling machine for soft fluid plastic formations, characterized in that, It includes the following steps: The selection of cutterhead and cutting tools is determined based on geological characteristics, construction environment, and engineering requirements; The layout design of the selected cutting tools was determined based on the special characteristics of the strata and the distribution features of the pile foundations. By constructing a predictive model for tool wear, the remaining life and replacement cycle of each tool mounted on the tool turret are quantified. When selecting a cutterhead, one or more continuous annular ribs (300) are configured between the main spoke (100) and the secondary spoke (200). The continuous annular rib (300) includes a high section (310) connected to the main spoke (100), a low section (320) connected to the secondary spoke (200), and a transition section (330) connecting the two. A first included angle is formed between the high section (310) and the transition section (330) so that the continuous annular rib (300) can uniformly transmit the cutting reaction force to the main spoke (100) when under stress. A second included angle is formed between the low section (320) and the transition section (330) to ensure the continuity of the soil flow path. The rib plate of the continuous annular rib (300) is constructed as a tortuous structure with at least two turns to reduce the wear of the cutter during construction in soft plastic strata, thereby improving the prediction quality of cutter wear.

2. The configuration method according to claim 1, characterized in that, The high section (310) of the continuous annular rib (300) is connected to the main spoke arm (100) through a high connection point (311), and the low section (320) is connected to the secondary spoke arm (200) through a low connection point (321). The connection between the high connection point (311) and the main spoke arm (100) adopts a reinforcing rib structure and is covered with a wear-resistant alloy coating. The connection between the low connection point (321) and the secondary spoke arm (200) adopts an arc transition design and is covered with a wear-resistant coating. The angle design of the first included angle and the second included angle of the continuous annular rib (300) is complementary to each other so that the high connection point (311) and the low connection point (321) of the continuous annular rib (300) have different axial heights.

3. The configuration method according to claim 2, characterized in that, The transition section (330) is configured as a transition curve. The high section (310) near the high connection point (311) has a relatively wider cross section. The transition curve after the transition section (330) gradually shrinks towards the low connection point (321) to form a tapered structure. The continuous annular rib (300) achieves dynamic screening of slag particle size through cross section change. The surface of the transition curve is covered with a wear-resistant coating to optimize the smoothness of slag flow and disperse stress.

4. The configuration method according to claim 1, characterized in that, In the selection of cutterhead tools, the tool type adaptability design is designed for the characteristics of soft plastic strata and reinforced concrete pile groups. The core combination is a roller cutter and a tearing cutter. The roller cutter controls the excavation diameter by rolling and breaking the concrete, while the tearing cutter cuts the concrete and cuts the reinforcing bars by punching and shearing. The two work together and are equipped with auxiliary tools including scrapers and / or shell cutters to meet the needs of scraping the excavated soil and secondary cutting of reinforcing bars.

5. The configuration method according to claim 1, characterized in that, The arrangement of the cutter head follows the dual principles of functional zoning and hierarchical layering. The cutter head layout is divided into an inner ring area (600), a middle ring area (500), and an outer ring area (400) corresponding to different cutting tasks and wear characteristics. A layered cutting strategy is formed by gradually decreasing the tool height to cope with the complex structure of reinforced concrete piles.

6. The configuration method according to claim 5, characterized in that, The inner ring area (600) is responsible for slag removal and preliminary cutting. It is equipped with a double tearing cutter and an auxiliary slag removal device, and the cutter spacing is relatively larger. The middle ring area (500) is the core cutting area, equipped with a front tearing cutter, and the cutter spacing is dynamically adjusted according to the cutting intensity. The outer ring area (400) is mainly for diameter protection and safety reserve, equipped with a combination of hobbing cutter and welded tearing cutter, and the cutter spacing is relatively smaller to improve tool density.

7. The configuration method according to claim 5, characterized in that, In the layered cutting strategy, the cutting tool is divided into a main layer, an auxiliary layer, and a terminal layer. The height of each layer decreases progressively. The main layer cutting tool first contacts the pile body and is responsible for crushing and initial cutting. The auxiliary layer is replaced after the main layer wears out. The terminal layer is responsible for stripping the concrete protective layer of the reinforcing steel and removing the reinforcing steel. The cutting force is dispersed by the height difference design, which reduces abnormal wear of the cutting tool.

8. The configuration method according to claim 1, characterized in that, In tool wear monitoring and prediction, tool wear forms include surface weld layer wear and alloy material spalling. One or more of the following data are collected through multi-dimensional sensors and manual inspection and substituted into the prediction model for calculation: trajectory radius, tool type, cutter head rotation direction, push speed and rotation speed, and pile foundation distribution pattern.

9. The configuration method according to claim 8, characterized in that, The tool wear prediction model calculates the cutting length and predicts the remaining life by combining the wear amount and wear coefficient. The cutting length calculation formula includes two cases: cutting through the pile foundation and not cutting through the pile foundation. The remaining allowable wear amount and remaining cutting length are determined based on the current wear amount and the critical wear amount.

10. The configuration method according to claim 9, characterized in that, Based on the wear prediction results and construction progress, the tool replacement decision is dynamically adjusted. In this process, the design of the composite cutter head opening ratio and the torque transmission optimization of the continuous annular rib (300) are combined. Different replacement cycles are set considering the differences in the wear coefficient of different tool types. The wear difference between the positive and negative cutting surfaces is balanced by adjusting the rotation direction of the cutter head.

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