Method and system for evaluating abrasion loss of shield cutter in composite stratum

Abstract

The invention relates to the technical field of shield cutter abrasion loss evaluation, in particular to a composite stratum shield cutter abrasion loss evaluation method and system, and the method comprises the steps: determining an abrasion loss evaluation strategy of a cutterhead based on a geological parameter fluctuation coefficient; under the condition that the uniform wear evaluation strategy is determined to be started, the reference wear amount of the cutterhead is determined based on the deformation synergy index, and an impact wear evaluation strategy is started; under the condition of determining to start the impact wear evaluation strategy, determining an impact risk level based on the strength ratio, and determining whether the cutter head has a fracture risk based on the fluctuation amplitude and the impact risk level so as to start an abnormal wear evaluation strategy; under the condition that it is determined that the abnormal wear evaluation strategy is started, a preset variable coefficient is optimized based on the evaluation reliability of the cutterhead wear extent; the system comprises a data acquisition module, a strategy determination module, a uniform wear evaluation module, an impact wear evaluation module and an abnormal wear evaluation module. According to the method, the evaluation precision of the cutter abrasion loss of the shield tunneling machine is improved.

Description

Technical Field

[0001] This invention relates to the field of shield cutter wear assessment technology, and in particular to a method and system for assessing shield cutter wear in composite strata. Background Technology

[0002] Complex strata, characterized by mixed lithology, drastic fluctuations in geological parameters, frequent abrupt interface changes, and unstable earth pressure and stratum resistance, present a typical complex scenario for tunnel boring machine (TBM) construction. As the core component of the TBM that directly cuts through the strata, the wear state of the cutterhead directly determines construction safety, tunneling efficiency, and project costs. Inaccurate wear assessment can easily lead to accidents such as sudden cutterhead failure, machine jamming, and excavation face collapse, or cause project delays and cost waste due to excessive cutterhead replacements. Existing cutterhead wear assessment methods have significant limitations: traditional manual inspection requires interrupting tunneling, has poor real-time performance, and cannot capture dynamic wear processes; single-sensor monitoring does not incorporate the geological fluctuation characteristics of complex strata, making it difficult to distinguish the causes of different wear types; some assessment models do not establish a quantitative correlation between geological parameters and wear states, leading to misjudgments or underestimations of impact and abnormal wear; furthermore, there is a lack of a closed-loop mechanism for back-optimizing preset parameters based on actual wear data, resulting in insufficient flexibility to adapt to different complex strata and an inability to provide a technical solution for real-time and accurate differentiation of wear types and dynamic optimization of assessment strategies. Consequently, the accuracy and adaptability of TBM cutterhead wear assessment in complex strata are poor.

[0003] Chinese Patent Application Publication No. CN119959227A discloses a method and system for monitoring the wear of tunnel boring machine (TBM) cutters. This invention constructs a linear equation by acquiring the deviation parameters between the TBM cutter profiles at various time points, calculates the cutter wear at each time point, and can acquire the cutter wear status in real time. By constructing a wear trace recognition model, it calculates the wear area on the cutter surface at each time point. Based on the cutter wear amount and cutter surface wear area at each time point, it assesses the degree of cutter wear at each time point. Combining the time series, it plots a curve showing the change in the degree of cutter wear over time, analyzes the wear trend of the TBM cutters, and can quickly understand the wear pattern of the cutters, predict the future wear of the cutters, ensure construction progress, and improve construction efficiency.

[0004] The existing technology also has the following problems: existing methods either rely on manual inspection during downtime, resulting in insufficient real-time performance, or they only use tunneling parameters or sensor signals, failing to effectively integrate the characteristics of mixed lithology and drastic fluctuations in geological parameters in composite strata. This makes it difficult to accurately distinguish the causes of uniform wear, impact wear, and abnormal wear, and easily leads to underestimation / overestimation of wear. This results in insufficient flexibility in adapting to different composite strata, ultimately leading to low accuracy in assessing cutter wear of tunnel boring machines for tunneling in composite strata. Summary of the Invention

[0005] To address this issue, the present invention provides a method and system for assessing the wear of shield tunneling cutters in composite strata. This method overcomes the problem in the prior art where the causes of uniform wear, impact wear, and abnormal wear cannot be accurately distinguished, leading to underestimation or overestimation of wear. This results in insufficient flexibility in adapting to different composite strata and ultimately low accuracy in assessing the wear of shield tunneling cutters in composite strata.

[0006] To achieve the above objectives, in one aspect, the present invention provides a system for assessing the wear of shield tunneling cutters in composite strata, comprising: The data acquisition module includes a torque sensor for real-time monitoring of the main drive torque of the tunnel boring machine cutterhead, a distributed earth pressure sensor and a ground-penetrating radar array for real-time monitoring of geological information; The strategy determination module is used to determine the cutterhead wear assessment strategy as uniform wear assessment strategy, impact wear assessment strategy or abnormal wear assessment strategy based on the comparison results of the geological parameter fluctuation coefficient within the current tunneling mileage and the preset fluctuation coefficient. The uniform wear assessment module responds to the determination result of the activation of the uniform wear assessment strategy, and is used to determine whether the reference wear amount of the cutter head is qualified based on the deformation coordination index of the cutter head, so as to activate the impact wear assessment strategy based on the impact component ratio of the cutter head vibration signal when the reference wear amount is not qualified. The impact wear assessment module, in response to the determination result of activating the impact wear assessment strategy, determines the impact risk level based on the strength ratio of the current stratum's soil and rock strength to the cutterhead's design strength, and determines whether the cutterhead has a fracture risk based on the fluctuation amplitude of the main drive torque and the impact risk level, so as to activate the abnormal wear assessment strategy under the condition that there is a fracture risk. An abnormal wear assessment module, in response to the determination result of activating the abnormal wear assessment strategy, optimizes the preset coefficient of variation based on the assessment reliability of the tool head wear amount.

[0007] Furthermore, the strategy determination module determines the wear assessment strategy of the cutterhead as an abnormal wear assessment strategy based on the comparison result that the geological parameter fluctuation coefficient is greater than the first preset fluctuation coefficient. The strategy determination module determines the cutterhead wear assessment strategy as an impact wear assessment strategy based on the comparison result that the geological parameter fluctuation coefficient is less than or equal to the first preset fluctuation coefficient and greater than the second preset fluctuation coefficient. The strategy determination module determines the cutterhead wear assessment strategy as a uniform wear assessment strategy based on the comparison result that the geological parameter fluctuation coefficient is less than or equal to the second preset fluctuation coefficient.

[0008] Furthermore, the uniform wear assessment module determines the ratio of the radial wear uniformity coefficient to the axial wear uniformity coefficient of the cutter head as the deformation synergy index.

[0009] Furthermore, the uniform wear assessment module determines that the reference wear amount of the cutter head is unqualified based on the comparison result of whether the deformation coordination index is greater than the second preset coordination index or less than the first preset coordination index.

[0010] Furthermore, the uniform wear assessment module determines to activate the impact wear assessment strategy based on the comparison result that the proportion of the impact component is greater than the preset proportion.

[0011] Furthermore, the impact wear assessment module determines the impact risk level as Level 1 based on the comparison result that the strength ratio is greater than the first preset strength ratio; The impact wear assessment module determines the impact risk level as Level II based on the comparison result that the strength ratio is less than or equal to the first preset strength ratio and greater than the second preset strength ratio; The impact wear assessment module determines the impact risk level as level three based on the comparison result that the strength ratio is less than or equal to the second preset strength ratio.

[0012] Furthermore, the impact wear assessment module determines that the tool has a risk of breakage based on the comparison result that the fluctuation amplitude of the main drive torque is greater than the preset amplitude and the impact risk level is level one or level two. The impact wear assessment module determines to activate the abnormal wear assessment strategy based on the comparison result that the fluctuation amplitude is greater than the preset amplitude and the impact risk level is three.

[0013] Furthermore, when the tool is at risk of fracture, the impact wear assessment module determines to activate the abnormal wear assessment strategy based on the comparison result that the tool temperature change rate is greater than the preset change rate.

[0014] Furthermore, the abnormal wear assessment module determines that the current wear assessment strategy is unqualified based on the comparison result where the assessment reliability is less than the preset reliability. Wherein, the abnormal wear assessment module, under the condition that the current wear assessment strategy is unqualified, determines to reduce the first preset fluctuation coefficient and the second preset fluctuation coefficient by a first fluctuation adjustment coefficient based on the comparison result that the difference between the preset reliability and the assessment reliability is greater than the preset reliability difference. The abnormal wear assessment module determines, based on the comparison result that the reliability difference is less than or equal to the preset reliability difference, to reduce the first preset fluctuation coefficient and the second preset fluctuation coefficient by the second fluctuation adjustment coefficient.

[0015] On the other hand, the present invention also provides a method for evaluating the wear of shield tunneling cutters in composite strata, comprising: Based on the comparison between the geological parameter fluctuation coefficient and the preset fluctuation coefficient within the current tunneling mileage, the wear assessment strategy for the cutterhead is determined to be either a uniform wear assessment strategy, an impact wear assessment strategy, or an abnormal wear assessment strategy. Under the condition of determining the activation of the uniform wear assessment strategy, the reference wear amount of the cutter head is determined based on the deformation coordination index of the cutter head. If the reference wear amount is not qualified, the impact wear assessment strategy is activated based on the impact component ratio of the cutter head vibration signal. Under the condition of determining to activate the impact wear assessment strategy, the impact risk level is determined based on the strength ratio of the current soil and rock strength to the cutterhead design strength. The presence of cutterhead fracture risk is determined based on the fluctuation amplitude of the main drive torque and the impact risk level, so that the abnormal wear assessment strategy can be activated under the condition of fracture risk. Under the condition that the abnormal wear assessment strategy is enabled, the reliability of the tool disc wear assessment is used to determine whether the current wear assessment strategy is qualified, and the preset coefficient of variation is optimized based on the unqualified judgment result.

[0016] Compared with existing technologies, the beneficial effects of this invention are that it determines whether the wear assessment strategy for tunnel boring machine (TBM) cutters matches the current geological conditions by real-time monitoring of the geological parameter fluctuation coefficient. The geological parameter fluctuation coefficient comprehensively reflects the frequency of lithological alternation, earth pressure fluctuation, and propulsion stability, and its value directly determines the dominant mode of cutter wear. If the fluctuation coefficient is low, it indicates that the strata are uniform and stable, and the cutter wear exhibits regular and uniform characteristics. In this case, the uniform wear assessment strategy can efficiently and accurately predict the wear amount based on the tunneling mileage. If the fluctuation coefficient is in the medium range, it indicates that there are intermittent impact loads in the strata, and the cutter wear is mainly impact wear. In this case, the impact wear assessment strategy can accurately correct the additional wear increment caused by impact by analyzing the vibration impact components and torque fluctuations. If the fluctuation coefficient is high, it indicates that the geological conditions are extremely complex, and the cutters face frequent impacts and local overloads. In this case, the abnormal wear assessment strategy can accurately identify abnormally worn cutters by monitoring the local wear of individual cutters and analyzing temperature changes, thereby improving the accuracy of the cutter wear assessment of the TBM.

[0017] Furthermore, this invention achieves precise identification and strategy switching of wear modes through deformation synergy index and impact component ratio. The deformation synergy index reveals the uniformity of tool wear from a spatial dimension; when the index deviates from the ideal range, it indicates that the wear mode has shifted from uniform to locally concentrated. The impact component ratio identifies the presence of impact loads from a dynamic dimension; when the ratio exceeds a threshold, it indicates that impact has become the dominant wear factor. The combination of these two factors forms a complete diagnostic chain from spatial distribution to dynamic response, ensuring the accuracy and timeliness of the switch from uniform wear assessment to impact wear assessment, thereby improving the accuracy of tool wear assessment for tunnel boring machines.

[0018] Furthermore, this invention establishes a self-optimization mechanism for the system by assessing reliability. When the reliability is insufficient, the trigger threshold of the assessment strategy is adjusted by dynamically optimizing the preset fluctuation coefficient, so that the system can adapt to the geological characteristics of specific projects and continuously improve the assessment accuracy. Attached Figure Description

[0019] Figure 1 This is a structural block diagram of the composite stratum shield tunneling cutter wear assessment system according to an embodiment of the present invention; Figure 2 A flowchart illustrating the strategy for determining the wear assessment of the cutterhead in an embodiment of the present invention; Figure 3 A flowchart for determining whether the reference wear amount of the cutter head is qualified in an embodiment of the present invention; Figure 4 This is a flowchart of the method for evaluating the wear of shield tunneling cutters in composite strata according to an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0021] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0022] It should also be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Please see Figure 1 As shown, it is a structural block diagram of the composite stratum shield cutter wear assessment system according to an embodiment of the present invention.

[0024] The composite strata shield tunneling cutter wear assessment system of this invention includes: The data acquisition module includes a torque sensor for real-time monitoring of the main drive torque of the tunnel boring machine cutterhead, a displacement sensor for real-time monitoring of the cylinder stroke, a speed sensor for monitoring the rotational speed of the tunnel boring machine's screw conveyor mechanism, a distributed earth pressure sensor and a ground radar array for real-time monitoring of geological information, and a triaxial accelerometer for acquiring the vibration acceleration of the cutterhead in the X, Y, and Z directions in a rotating coordinate system. The strategy determination module is used to determine the cutterhead wear assessment strategy as uniform wear assessment strategy, impact wear assessment strategy or abnormal wear assessment strategy based on the comparison results of the geological parameter fluctuation coefficient within the current tunneling mileage and the preset fluctuation coefficient. The uniform wear assessment module responds to the determination result of the activation of the uniform wear assessment strategy, and is used to determine whether the reference wear amount of the cutter head is qualified based on the deformation coordination index of the cutter head, so as to activate the impact wear assessment strategy based on the impact component ratio of the cutter head vibration signal when the reference wear amount is not qualified. The impact wear assessment module, in response to the determination result of activating the impact wear assessment strategy, determines the impact risk level based on the strength ratio of the current stratum's soil and rock strength to the cutterhead's design strength, and determines whether the cutterhead has a fracture risk based on the fluctuation amplitude of the main drive torque and the impact risk level, so as to activate the abnormal wear assessment strategy under the condition that there is a fracture risk. An abnormal wear assessment module, in response to the determination result of activating the abnormal wear assessment strategy, optimizes the preset coefficient of variation based on the assessment reliability of the tool head wear amount.

[0025] Specifically, torque sensors include, for example, the Kistler 4520A series; displacement sensors include, for example, the RB heavy-duty magnetostrictive displacement sensor; speed sensors include, for example, the 907 XP Hall effect speed sensor; distributed earth pressure sensors include, for example, the Trafag NAT 8251.31.2517; ground-penetrating radar arrays include, for example, the BMRD tunneling machine radar 3D system; and triaxial acceleration sensors include, for example, the Kistler 8763B series. The sensor models in this embodiment are only examples, and the specific models and parameters are not limited.

[0026] Specifically, the strategy determination module determines the geological parameter fluctuation coefficient by weighting the interface variation index, mechanical fluctuation index, and propulsion stability index. Specifically, the interface variation index is determined based on monitoring data from a ground-penetrating radar array. The ground-penetrating radar data is used to extract geological interface information. By using ground-penetrating radar reflected wave signals, the interfaces of different soil and rock layers, such as clay, sand, and rock, are identified and located within the length of the tunneling ring. The interface variation index is determined by multiplying the ratio of the number of interfaces appearing per unit tunneling length to the standard number, and the standard deviation of the spacing between interfaces. The standard number refers to the preset reference value for soil and rock layer interfaces within a unit standard tunneling length for the target geological stratum type. The mechanical fluctuation index is the ratio of the standard deviation to the average value of the monitoring data from the distributed earth pressure sensor. The propulsion stability index is the ratio of the standard deviation to the average value of the propulsion speed. The propulsion speed is calculated based on the monitoring results of the displacement sensor monitoring the cylinder stroke; this is existing technology and will not be elaborated further. The weighting coefficients for the interface variation index, mechanical fluctuation index, and propulsion stability index are 0.5, 0.3, and 0.2, respectively. However, these values ​​are not limited to these values, and those skilled in the art can choose values ​​according to actual needs.

[0027] Please see Figure 2 As shown, it is a flowchart of the strategy for determining the wear of the cutter head in an embodiment of the present invention.

[0028] Specifically, the strategy determination module determines the wear assessment strategy of the cutterhead as an abnormal wear assessment strategy based on the comparison result that the geological parameter fluctuation coefficient is greater than the first preset fluctuation coefficient. The strategy determination module determines the cutterhead wear assessment strategy as an impact wear assessment strategy based on the comparison result that the geological parameter fluctuation coefficient is less than or equal to the first preset fluctuation coefficient and greater than the second preset fluctuation coefficient. The strategy determination module determines the cutterhead wear assessment strategy as a uniform wear assessment strategy based on the comparison result that the geological parameter fluctuation coefficient is less than or equal to the second preset fluctuation coefficient.

[0029] Specifically, the first preset fluctuation coefficient is 0.35 and the second preset fluctuation coefficient is 0.15, but the above values ​​are not limited to these, and those skilled in the art can also choose values ​​according to actual needs.

[0030] Specifically, the interface variation index reflects the frequency of lithological alternation, such as short-distance cycles of clay-sand-hard rock, and the dispersion of interface distribution. The more interfaces and the more chaotic their distribution, the more frequently the cutterhead needs to switch cutting modes, causing the stress to change from stable to abrupt, and the wear to change from uniform to impact / localized. The mechanical fluctuation index reflects earth pressure fluctuations; large earth pressure fluctuations indicate unstable excavation face resistance, leading to drastic changes in cutterhead cutting resistance, equivalent to repeated impact loads, accelerating cutterhead tool edge wear. The propulsion stability index represents propulsion speed fluctuations; large propulsion speed fluctuations, such as those caused by abrupt changes in geological resistance leading to inconsistent speed, result in uneven cutting contact time and pressure between the cutterhead and the strata, further amplifying localized wear. Therefore, the higher the fluctuation coefficient, the stronger the geological interference and impact on the cutterhead, and the more the wear type deviates from uniform wear; the lower the fluctuation coefficient, the more stable the geology, and the more regular the cutterhead wear. In geological conditions with extremely drastic changes, such as fractured zones with frequent alternations in lithology and water-rich sand layers, the cutterhead faces frequent impacts and localized overloads. For example, a certain cutter repeatedly cuts hard rock while other cutters cut soft soil. In this case, the wear characteristics of the cutterhead are non-uniform and localized abnormal wear, such as cutter ring cracking, uneven wear, and localized spalling, rather than overall uniform wear. If the conventional uniform wear assessment method, which estimates linearly based on the tunneling mileage, is used, the amount of localized abnormal wear will be severely underestimated, leading to the failure of a single cutter and the risk of machine jamming and collapse. Therefore, an abnormal wear assessment strategy is required, which focuses on detecting the localized wear of individual cutters, inferring the impact frequency from torque fluctuation data, and combining this with the analysis of cutter debris in the excavated soil to accurately locate abnormally worn cutters. For geological conditions with variations but not extremes, such as a small amount of hard rock interlayers with homogeneous sand layers or shallowly buried transitional strata, the cutterhead is subjected to intermittent impact loads, such as occasional encounters with gravel or sudden changes in lithology leading to a surge in resistance. The wear characteristic is mainly impact wear, with the wear amount falling between uniform and abnormal. If uniform wear assessment is used, the additional wear increment caused by impact will be ignored; if abnormal wear assessment is used, there will be an overemphasis on local areas, wasting detection resources. Therefore, an impact wear assessment strategy is required, combining impact frequency and peak cutterhead stress to correct the wear amount model, neither underestimating impact loss nor blindly investigating individual cutters. For geological conditions with uniform and stable geology, such as thick pure clay layers or homogeneous hard rock, the cutterhead is subjected to stable stress and consistent cutting conditions. The wear characteristic is regular uniform wear, with the overall thickness of the cutter ring decreasing uniformly, without local collapse or uneven wear. In this case, uniform wear assessment based on tunneling mileage and cutting time is completely effective. For example, if the cutterhead wears uniformly by 3mm for every 200m of tunneling, no complex detection is required. This is both efficient and accurately reflects the actual wear amount, avoiding over-assessment and increased construction costs.

[0031] Specifically, the uniform wear assessment module determines the ratio of the radial wear uniformity coefficient to the axial wear uniformity coefficient of the cutter head as the deformation synergy index.

[0032] Specifically, the radial wear uniformity coefficient is the ratio of the standard deviation to the average value of the radial wear depth of all tools on the same annular surface along the radius of the cutter head, and the axial wear uniformity coefficient is the ratio of the standard deviation to the average value of the axial wear depth of all tools on the same annular surface along the tunnel axis.

[0033] Please see Figure 3 As shown, it is a flowchart for determining whether the reference wear amount of the cutter head is qualified according to an embodiment of the present invention.

[0034] Specifically, the uniform wear assessment module determines that the reference wear amount of the cutter head is unqualified based on the comparison result that the deformation coordination index is greater than the second preset coordination index or less than the first preset coordination index; The uniform wear assessment module determines that the reference wear amount of the cutter head is qualified based on the comparison result that the deformation coordination index is less than or equal to the second preset coordination index and greater than or equal to the first preset coordination index.

[0035] Specifically, the first preset synergy index is 0.8, and the second preset synergy index is 1.2. However, the above values ​​are not limited to these, and those skilled in the art can also choose values ​​according to actual needs.

[0036] It is understandable that when the deformation coordination index is 1, the radial and axial wear uniformity of the cutterhead is completely consistent, and the wear pattern is ideal. When the deformation coordination index is >1, the radial wear non-uniformity is greater than that of the axial wear, and the cutterhead tool exhibits uneven wear characteristics, which is common in formations with uneven hardness. When the deformation coordination index is <1, the axial wear non-uniformity is greater than that of the radial wear, and the cutterhead tool exhibits stepped wear, which is common in working conditions with large thrust fluctuations.

[0037] Specifically, the uniform wear assessment module performs wavelet packet transform on the vibration acceleration time-domain signal collected by the triaxial accelerometer, decomposes the signal into sub-bands covering different frequency ranges, extracts the high-frequency sub-band signal in the range of 200Hz-300Hz, and determines the ratio of the energy value of the high-frequency sub-band to the total energy value of the vibration signal as the impact component proportion.

[0038] Specifically, the uniform wear assessment module determines to activate the impact wear assessment strategy based on the comparison result that the proportion of the impact component is greater than the preset proportion; The uniform wear assessment module determines a strategy to maintain uniform wear based on a comparison of whether the proportion of the impact component is less than or equal to the preset proportion.

[0039] Specifically, the preset intensity is set to a value range of [0.15, 0.3], and preferably 0.2 in this embodiment of the invention.

[0040] Understandably, a smooth cutterhead vibration with a low proportion of high-frequency impact components in the 200Hz-300Hz range indicates a uniform stratum, stable tool cutting resistance, and no significant impact load. The tool wear is primarily characterized by uniform thinning. If impact wear assessment is initiated at this time, the slight vibrations of normal cutting will be misjudged as impacts, leading to an inflated wear calculation and unnecessary downtime for inspection or tool replacement. A high proportion of high-frequency impact components indicates that the tool frequently encounters impacts, with impact loads becoming the core factor dominating wear. The cutting edge develops microcracks, localized chipping, and uneven wear due to repeated instantaneous impacts, and the wear increment caused by impacts is far greater than that of uniform cutting. If a uniform wear assessment strategy is continued, and only linear estimation is based on mileage, the localized concentrated damage caused by impacts will be completely ignored.

[0041] Specifically, the impact wear assessment module determines the impact risk level as Level 1 based on the comparison result that the strength ratio is greater than the first preset strength ratio; The impact wear assessment module determines the impact risk level as Level II based on the comparison result that the strength ratio is less than or equal to the first preset strength ratio and greater than the second preset strength ratio; The impact wear assessment module determines the impact risk level as level three based on the comparison result that the strength ratio is less than or equal to the second preset strength ratio.

[0042] Specifically, the current soil and rock strength of the underlying layer is output by a regression model pre-trained from a large amount of geological exploration data and corresponding tunneling data. The total thrust provided by the shield machine jacks, the total torque required to drive the cutterhead, the ratio of cutterhead rotation speed to propulsion speed, and the soil chamber pressure are input into the regression model to output the current soil and rock strength of the underlying layer.

[0043] Specifically, the first preset strength ratio is 0.8 and the second preset strength ratio is 0.5, but the above values ​​are not limited to these, and those skilled in the art can also choose values ​​according to actual needs.

[0044] Specifically, the impact wear assessment module determines that the tool is at risk of breakage based on the comparison result that the fluctuation amplitude of the main drive torque is greater than the preset amplitude and the impact risk level is level one or level two. The impact wear assessment module determines to activate the abnormal wear assessment strategy based on the comparison result that the fluctuation amplitude is greater than the preset amplitude and the impact risk level is three.

[0045] Specifically, when the tool is at risk of fracture, the impact wear assessment module determines to activate the abnormal wear assessment strategy based on the comparison result that the tool temperature change rate is greater than the preset change rate.

[0046] Specifically, the preset amplitude is set to a range of [15%, 30%], and in this embodiment of the invention, 20% is preferred. The preset rate of change is set to a range of [1℃ / min, 2℃ / min], and in this embodiment of the invention, 1.5℃ / min is preferred.

[0047] Specifically, the abnormal wear assessment module determines that the current wear assessment strategy is qualified based on the comparison result that the assessment reliability is greater than or equal to the preset reliability; The abnormal wear assessment module determines that the current wear assessment strategy is unqualified based on the comparison result that the assessment reliability is less than the preset reliability.

[0048] Specifically, the assessment reliability is the ratio of the measured value of the cutter head wear to the output value of the wear assessment strategy.

[0049] Specifically, the preset reliability range is set to [85%, 95%], and 90% is preferred in this embodiment of the invention.

[0050] Specifically, when the abnormal wear assessment module determines that the current wear assessment strategy is unqualified, it determines to reduce the first preset fluctuation coefficient and the second preset fluctuation coefficient by using the first fluctuation adjustment coefficient based on the comparison result that the difference between the preset reliability and the assessment reliability is greater than the preset reliability difference. The abnormal wear assessment module determines, based on the comparison result that the reliability difference is less than or equal to the preset reliability difference, to reduce the first preset fluctuation coefficient and the second preset fluctuation coefficient by the second fluctuation adjustment coefficient.

[0051] Specifically, the preset reliability difference value range is set to [5%, 8%], and 6% is preferred in this embodiment of the invention; the first fluctuation adjustment coefficient range is set to [0.85, 0.9], and 0.88 is preferred in this embodiment of the invention; the second fluctuation adjustment coefficient range is set to [0.91, 0.95], and 0.93 is preferred in this embodiment of the invention.

[0052] Specifically, the essence of an inadequate assessment strategy is that the output value of the wear assessment deviates too much from the measured value. The root cause lies in the overly lenient preset fluctuation coefficient, which fails to capture the actual impact of geological fluctuations on tool wear in a timely manner. This leads to a lag in the switching of the assessment strategy; when an impact / abnormal assessment should be triggered, the original strategy is still used, ultimately underestimating the wear amount. Reducing the preset fluctuation coefficient and tightening the trigger threshold of the assessment strategy makes the system more sensitive to geological fluctuations, allowing it to switch to an appropriate wear assessment strategy earlier and more accurately, thereby reducing the deviation between the assessed and measured values ​​and improving the reliability of subsequent assessments.

[0053] Please see Figure 4As shown, it is a flowchart of the method for evaluating the wear of shield tunneling cutters in composite strata according to an embodiment of the present invention.

[0054] The method for evaluating the wear of shield tunneling cutters in composite strata according to embodiments of the present invention includes: Step S1: Based on the comparison results of the geological parameter fluctuation coefficient within the current tunneling mileage and the preset fluctuation coefficient, determine the wear assessment strategy of the cutterhead as a uniform wear assessment strategy, an impact wear assessment strategy, or an abnormal wear assessment strategy. Step S2: Under the condition of determining the activation of the uniform wear assessment strategy, determine whether the reference wear amount of the cutter head is qualified based on the deformation coordination index of the cutter head, so as to activate the impact wear assessment strategy based on the impact component ratio of the cutter head vibration signal if the reference wear amount is not qualified. Step S3: Under the condition of determining to activate the impact wear assessment strategy, determine the impact risk level based on the strength ratio of the current stratum soil strength to the cutterhead design strength, and determine whether there is a risk of cutterhead fracture based on the fluctuation amplitude of the main drive torque and the impact risk level, so as to activate the abnormal wear assessment strategy under the condition of fracture risk. Step S4: Under the condition that the abnormal wear assessment strategy is enabled, determine whether the current wear assessment strategy is qualified based on the assessment reliability of the tool disc wear amount, and optimize the preset coefficient of variation based on the unqualified judgment result.

[0055] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A system for assessing the wear of shield tunneling cutters in composite strata, characterized in that, include: The data acquisition module includes a torque sensor for real-time monitoring of the main drive torque of the tunnel boring machine cutterhead, a distributed earth pressure sensor and a ground-penetrating radar array for real-time monitoring of geological information; The strategy determination module is used to determine the cutterhead wear assessment strategy as uniform wear assessment strategy, impact wear assessment strategy or abnormal wear assessment strategy based on the comparison results of the geological parameter fluctuation coefficient within the current tunneling mileage and the preset fluctuation coefficient. The uniform wear assessment module responds to the determination result of the activation of the uniform wear assessment strategy, and is used to determine whether the reference wear amount of the cutter head is qualified based on the deformation coordination index of the cutter head, so as to activate the impact wear assessment strategy based on the impact component ratio of the cutter head vibration signal when the reference wear amount is not qualified. The impact wear assessment module, in response to the determination result of activating the impact wear assessment strategy, determines the impact risk level based on the strength ratio of the current stratum's soil and rock strength to the cutterhead's design strength, and determines whether the cutterhead has a fracture risk based on the fluctuation amplitude of the main drive torque and the impact risk level, so as to activate the abnormal wear assessment strategy under the condition that there is a fracture risk. An abnormal wear assessment module, in response to the determination result of activating the abnormal wear assessment strategy, optimizes the preset coefficient of variation based on the assessment reliability of the tool head wear amount.

2. The composite strata shield tunneling cutter wear assessment system according to claim 1, characterized in that, The strategy determination module determines the cutterhead wear assessment strategy as an abnormal wear assessment strategy based on the comparison result that the geological parameter fluctuation coefficient is greater than the first preset fluctuation coefficient. The strategy determination module determines the cutterhead wear assessment strategy as an impact wear assessment strategy based on the comparison result that the geological parameter fluctuation coefficient is less than or equal to the first preset fluctuation coefficient and greater than the second preset fluctuation coefficient. The strategy determination module determines the cutterhead wear assessment strategy as a uniform wear assessment strategy based on the comparison result that the geological parameter fluctuation coefficient is less than or equal to the second preset fluctuation coefficient.

3. The composite stratum shield tunneling cutter wear assessment system according to claim 2, characterized in that, The uniform wear assessment module determines the ratio of the radial wear uniformity coefficient to the axial wear uniformity coefficient of the cutter head as the deformation synergy index.

4. The composite stratum shield tunneling cutter wear assessment system according to claim 3, characterized in that, The uniform wear assessment module determines that the reference wear amount of the cutter head is unqualified based on the comparison result of the deformation synergy index being greater than the second preset synergy index or less than the first preset synergy index.

5. The composite stratum shield tunneling cutter wear assessment system according to claim 4, characterized in that, The uniform wear assessment module determines to activate the impact wear assessment strategy based on the comparison result that the proportion of the impact component is greater than the preset proportion.

6. The composite stratum shield tunneling cutter wear assessment system according to claim 5, characterized in that, The impact wear assessment module determines the impact risk level as Level 1 based on the comparison result that the strength ratio is greater than the first preset strength ratio; The impact wear assessment module determines the impact risk level as Level II based on the comparison result that the strength ratio is less than or equal to the first preset strength ratio and greater than the second preset strength ratio; The impact wear assessment module determines the impact risk level as level three based on the comparison result that the strength ratio is less than or equal to the second preset strength ratio.

7. The composite stratum shield tunneling cutter wear assessment system according to claim 6, characterized in that, The impact wear assessment module determines that the tool has a risk of breakage based on the comparison result that the fluctuation amplitude of the main drive torque is greater than the preset amplitude and the impact risk level is level one or level two. The impact wear assessment module determines to activate the abnormal wear assessment strategy based on the comparison result that the fluctuation amplitude is greater than the preset amplitude and the impact risk level is three.

8. The composite stratum shield tunneling cutter wear assessment system according to claim 7, characterized in that, When the tool is at risk of fracture, the impact wear assessment module determines to activate the abnormal wear assessment strategy based on the comparison result that the tool temperature change rate is greater than the preset change rate.

9. The composite stratum shield tunneling cutter wear assessment system according to claim 8, characterized in that, The abnormal wear assessment module determines that the current wear assessment strategy is unqualified based on the comparison result that the assessment reliability is less than the preset reliability. Wherein, the abnormal wear assessment module, under the condition that the current wear assessment strategy is unqualified, determines to reduce the first preset fluctuation coefficient and the second preset fluctuation coefficient by a first fluctuation adjustment coefficient based on the comparison result that the difference between the preset reliability and the assessment reliability is greater than the preset reliability difference. The abnormal wear assessment module determines, based on the comparison result that the reliability difference is less than or equal to the preset reliability difference, to reduce the first preset fluctuation coefficient and the second preset fluctuation coefficient by the second fluctuation adjustment coefficient.

10. A method for assessing the wear of shield tunneling cutters in composite strata using the composite strata shield tunneling cutter wear assessment system according to any one of claims 1-9, characterized in that, include: Based on the comparison between the geological parameter fluctuation coefficient and the preset fluctuation coefficient within the current tunneling mileage, the wear assessment strategy for the cutterhead is determined to be either a uniform wear assessment strategy, an impact wear assessment strategy, or an abnormal wear assessment strategy. Under the condition of determining the activation of the uniform wear assessment strategy, the reference wear amount of the cutter head is determined based on the deformation coordination index of the cutter head. If the reference wear amount is not qualified, the impact wear assessment strategy is activated based on the impact component ratio of the cutter head vibration signal. Under the condition of determining to activate the impact wear assessment strategy, the impact risk level is determined based on the strength ratio of the current soil and rock strength to the cutterhead design strength. The presence of cutterhead fracture risk is determined based on the fluctuation amplitude of the main drive torque and the impact risk level, so that the abnormal wear assessment strategy can be activated under the condition of fracture risk. Under the condition that the abnormal wear assessment strategy is enabled, the reliability of the tool disc wear assessment is used to determine whether the current wear assessment strategy is qualified, and the preset coefficient of variation is optimized based on the unqualified judgment result.

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