Cutterhead hob mechanical penetration stratum monitoring method

Abstract

The invention relates to the technical field of tunnel engineering construction, in particular to a monitoring method for a cutterhead hob mechanical penetration stratum. Comprising the following steps: collecting high-frequency changes of displacement and force generated by mechanical sounding and cutting of a stratum tunnel face by a shield cutterhead hob cutter; establishing a stratigraphic mechanics parameter mathematical model through a rock-soil mechanics theory; carrying out inversion through a least square method, analyzing formation mechanical parameters, and carrying out spatial interpolation on the tunnel face to obtain formation mechanical parameter distribution of the whole tunnel face; kriging interpolation is adopted for interpolation calculation, formation mechanical parameter distribution is displayed in a visual mode through a GIS, and the real-time condition of the tunnel face formation is visually displayed. According to the cutterhead hob mechanical penetration stratum monitoring method, mechanical parameters of the stratum can be obtained in real time in the tunneling process of a shield tunneling machine, and accurate stratum information is provided for construction decision making.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering construction, and particularly relates to a monitoring method for a cutter head hob to mechanically penetrate the formation. Background Art

[0002] In shield tunneling construction, accurately grasping the formation conditions is crucial for construction safety and efficiency. Different formation characteristics, such as the hardness, density, water content, etc. of hard rock formations, will have a significant impact on the wear, tunneling speed, thrust, etc. of the cutter head hobs of the shield machine. Currently, common formation detection methods mainly include geological exploration boreholes, geophysical exploration methods, etc., but these methods have certain limitations. Geological exploration boreholes can only obtain formation information at limited locations and have a certain lag; although geophysical exploration methods can detect the formation within a certain range, the quantitative analysis of formation parameters is not accurate enough. Therefore, a technology that can monitor the mechanical properties of the formation in front of the cutter head in real time and accurately during shield tunneling is needed to guide the adjustment of the tunneling parameters of the shield machine, reduce construction risks, and improve construction efficiency.

[0003] Patent 202110183343.6, a method for identifying and determining formation characteristics using real-time shield tunneling parameters, pre-classifies the formation by collecting interval exploration reports, transforms the real-time shield tunneling parameters into FPI and TPI indices, and analyzes them by the K-Means algorithm to determine the formation classification. However, this patent mainly identifies the formation through real-time shield tunneling parameters as an "indirect method", inferring the formation conditions through changes in parameters such as tunneling speed and cutter head torque.

[0004] Patent 202311621154.8, an advanced geological detection method and device mounted on an extra-large diameter slurry shield, uses an advanced geological prediction system to obtain formation seismic wave signals and achieves the accuracy of geological detection through multiple denoising. However, this patent cannot detect the geological conditions during shield machine tunneling, requires shutdown for detection, and can only provide geological information at discrete points, making it difficult to meet the requirements for accurate and real-time information of the formation in front during shield machine tunneling.

[0005] Patent 201610957496.0, a construction method and system for advanced detection during shield tunneling in marine formations, arranges seismic wave transmitters at multiple positions on the cutter head, and improves the prediction accuracy of geological conditions based on the special coded sound transmission signals formed by seismic waves. However, the detection points of this patent are installed on the cutter head structure, the detection range is not direct, small-diameter boulders cannot be detected, and the formation boundary detection is not obvious. Summary of the Invention

[0006] The object of the present invention is to provide a mechanical penetration formation monitoring method for cutter head cutters, which can obtain the mechanical parameters of the formation in real time during the tunneling process of a shield machine and provide accurate formation information for construction decision-making.

[0007] The technical solution adopted by the present invention is as follows: A monitoring method for mechanical penetration of the formation by cutter head cutters, characterized by comprising the following steps:

[0008] Step 1, data acquisition: Install a force sensor and a displacement sensor on the cutter of the cutter head of the shield machine, and collect the resistance data F meas and displacement data s in real time when the cutter penetrates the formation. The force sensor is installed at the connection part between the cutter and the cutter box, and the displacement sensor is installed on the cutter shaft component of the cutter, and the measurement direction is consistent with the displacement direction of the cutter;

[0009] Step 2, mathematical model establishment: Based on geotechnical mechanics theory, establish a function relationship model between the cutter resistance F and the formation mechanical parameters. The formation mechanical parameters include compressive strength q, internal friction angle υ, and cohesion c. The model correlates the cutter resistance F with the formation parameters through elastic mechanics theory or Mohr-Coulomb strength criterion;

[0010] Step 3, parameter inversion: Use the least squares method to construct an objective function, and perform inversion calculation on the resistance data and displacement data F meas through the Newton-Raphson iteration algorithm to solve the optimal solution of the formation mechanical parameters;

[0011] Step 4, interpolation and visualization: Use the Kriging interpolation algorithm to perform spatial interpolation on the formation mechanical parameters of the heading face, and combine with the GIS platform to display the interpolation results in a visual form, and present the dynamic information of the formation compressive strength, internal friction angle, cohesion and boulder distribution in real time.

[0012] As a further improvement of the present invention, the data acquisition frequency in Step 1 is dynamically adjusted according to the tunneling speed of the shield machine and the formation change: when the tunneling speed is higher than the preset threshold or the formation change amplitude exceeds the set range, the acquisition frequency is 50-100 times per second; when the tunneling speed is lower than the preset threshold and the formation is stable, the acquisition frequency is 5-30 times per second.

[0013] As a further improvement of the present invention, the function relationship model between the cutter resistance F and the formation parameters in Step 2 is: F = g(q, υ, c, s), where g is a non-linear function based on the cutter geometry, cutting method and formation plastic deformation characteristics.

[0014] As a further improvement of the present invention, the objective function in Step 3 is: where F pred,i is the model predicted resistance value, and the formation parameters are iteratively optimized through the Jacobian matrix.

[0015] As a further improvement of the present invention, in step four, the Kriging interpolation algorithm solves the weight coefficient λ by constructing a Kriging equation system i , and combines the variogram to perform spatial estimation on the formation mechanical parameters of the unknown points on the tunnel face.

[0016] As a further improvement of the present invention, the visualization form includes a coordinate curve graph and a three-dimensional model graph. Among them, the coordinate curve graph is used to display the change trend of the formation mechanical parameters over time; the three-dimensional model graph visually presents the spatial distribution of the formation mechanical parameters through color and height differences.

[0017] As a further improvement of the present invention, the hob penetration unit includes a penetration rod and a penetration head. Among them, the penetration rod is made of a high-strength alloy material, and the surface of the penetration head is provided with a wear-resistant coating.

[0018] As a further improvement of the present invention, the sensor data is subjected to noise suppression through the Kalman filtering algorithm to improve the accuracy of formation parameter inversion.

[0019] Beneficial effects of the present invention: The present invention adopts a mechanical penetration method, integrates the penetration unit on the cutter head hob, and synchronously monitors the formation during the shield tunneling process, breaking through the limitations of traditional detection methods in terms of real-time performance and accuracy, and can directly obtain the true mechanical information of the formation in front of the cutter head. By comprehensively using force sensors and displacement sensors, the resistance and displacement during the penetration process are measured simultaneously, providing rich data support for accurately analyzing the mechanical properties of the formation. Through the analysis and processing of the force-displacement curve, the properties of the formation can be understood more comprehensively and deeply. Description of the Drawings

[0020] Figure 1 is a flow chart of a monitoring method for mechanically probing the formation with a cutter head hob of the present invention;

[0021] Figure 2 is a schematic diagram of establishing a mathematical model of a monitoring method for mechanically probing the formation with a cutter head hob of the present invention;

[0022] Figure 3 is a GIS visualization schematic diagram of a monitoring method for mechanically probing the formation with a cutter head hob of the present invention. Detailed Embodiments

[0023] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the following further details the present application in conjunction with the drawings and embodiments. It should be understood that the embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] The present invention provides a monitoring method for a cutter head hob to mechanically penetrate the formation, comprising the following steps:

[0025] Step 1, data acquisition: Install a force sensor and a displacement sensor on the hob cutter of the shield machine cutter head to collect the resistance data F meas and displacement data s in real time. The force sensor is installed at the connection part between the hob and the cutter box, and the displacement sensor is installed on the hob cutter shaft component. The measurement direction is consistent with the displacement direction of the hob. The data acquisition frequency is dynamically adjusted according to the tunneling speed of the shield machine and the formation change: when the tunneling speed is higher than the preset threshold or the formation change amplitude exceeds the set range, the acquisition frequency is 50 - 100 times per second; when the tunneling speed is lower than the preset threshold and the formation is stable, the acquisition frequency is 5 - 30 times per second;

[0026] Step 2, mathematical model establishment: Based on geotechnical mechanics theory, establish a function relationship model between the hob resistance F and the formation mechanical parameters. The formation mechanical parameters include the compressive strength q, the internal friction angle υ, and the cohesion c. The model correlates the hob resistance F with the formation parameters through the elastic mechanics theory or the Mohr - Coulomb strength criterion. The function relationship model between the hob resistance F and the formation parameters is: F = g(q, υ, c, s), where g is a non - linear function based on the hob geometry, cutting mode, and formation plastic deformation characteristics;

[0027] Step 3, parameter inversion: Use the least - squares method to construct an objective function, and perform inversion calculation on the resistance data and displacement data F meas through the Newton - Raphson iterative algorithm to solve the optimal solution of the formation mechanical parameters. The objective function is: where F pred,i is the model - predicted resistance value, and the formation parameters are iteratively optimized through the Jacobian matrix;

[0028] Step 4, interpolation and visualization: Use the Kriging interpolation algorithm to perform spatial interpolation on the formation mechanical parameters of the tunnel face, and combine with the GIS platform to display the interpolation results in a visual form, presenting the dynamic information of the formation compressive strength, internal friction angle, cohesion, and boulder distribution in real time. The Kriging interpolation algorithm solves the weight coefficient λ i by constructing a Kriging equation system, and combines with the variogram to perform spatial estimation of the formation mechanical parameters of the unknown points on the tunnel face.

[0029] In the present invention, the visual form includes a coordinate curve graph and a three - dimensional model graph. Among them, the coordinate curve graph is used to display the change trend of the formation mechanical parameters over time; the three - dimensional model graph visually presents the spatial distribution of the formation mechanical parameters through color and height differences.

[0030] In the present invention, the hob penetration unit includes a penetration rod and a penetration head. Among them, the penetration rod is made of a high-strength alloy material, and the surface of the penetration head is provided with a wear-resistant coating. The sensor data is subjected to noise suppression by the Kalman filtering algorithm to improve the accuracy of formation parameter inversion.

[0031] Embodiment:

[0032] This embodiment provides a monitoring method for the mechanical penetration of the cutter head hob into the formation, and the specific implementation method is as follows.

[0033] Step 1, data acquisition

[0034] It includes a penetration rod and a penetration head installed on the cutter body of the cutter head hob or on the hob cutter box. The penetration rod is made of a high-strength alloy material and has good bending and compressive resistance. The surface of the penetration head is provided with a wear-resistant coating to reduce wear during the penetration process. A displacement sensor and a force sensor are installed on the penetration rod. The displacement sensor is used to measure the displacement of the penetration rod, and the force sensor is used to measure the resistance received by the penetration head during the penetration process.

[0035] The displacement sensor is installed on the hob cutter shaft component, and the measurement direction is consistent with the displacement direction of the hob to accurately obtain displacement data. Considering the looseness generated during the vibration of the shield machine, the sensor is embedded at the hob cutter shaft and fastened by bolts to prevent the measurement accuracy from being affected by looseness.

[0036] The force sensor is installed at the connection part between the hob and the cutter box and can directly measure the resistance received by the hob during the cutting of the formation.

[0037] The data acquisition frequency is controlled by the internal calculation of the PLC according to the tunneling speed of the shield machine and the formation change situation. When the tunneling speed is fast or the formation changes greatly, the acquisition frequency will be increased to 50 - 100 times per second, and when the tunneling speed is slow and the formation is relatively stable, the acquisition frequency will be reduced to 5 - 30 times.

[0038] Step 2, mathematical model establishment

[0039] During the process of the mechanical penetration of the shield cutter head hob into the soil layer, the displacement sensor and the force sensor record data such as penetration force and displacement through the cutting trajectory of the cutter. Establish a mathematical model of formation mechanical parameters and use the inversion algorithm to solve the formation parameters.

[0040] The formation mechanical parameters mainly include the compressive strength q, the internal friction angle υ, the cohesion c, etc. When the hob cuts the formation, its force condition is closely related to the formation mechanical parameters. A mathematical model is established through geotechnical mechanics theory and hob cutting principle.

[0041] Assume that the formation is an elastic body. According to the theory of elasticity, the resistance F acting on the hob is related to the elastic modulus E, Poisson's ratio v of the formation, and the displacement s of the hob. For plane strain problems, under certain simplified conditions, the resistance F acting on the hob is expressed as: F = f(E, v, s), where f is a functional relationship, and its specific form is related to factors such as the shape of the hob and the cutting method.

[0042] Considering the plastic deformation of the formation, using the Mohr-Coulomb strength criterion, and combining with the stress analysis during the cutting process of the hob, establish the relationship between the hob resistance and the uniaxial compressive strength q, internal friction angle υ, and cohesion c of the formation. Under simplified conditions, the resistance F acting on the hob is expressed as: F = g(q, υ, c, s), where g is a functional relationship.

[0043] Step 3: Parameter inversion

[0044] Construct an objective function. Let the measured hob resistance data be F meas,i (i = 1, 2, ···, n), and the predicted hob resistance by the model be F pred,i = f(q, υ, c, s i , u i , ω i , D, θ), where q is the uniaxial compressive strength of the formation. Then the sum of squared errors S is:

[0045]

[0046] Partial derivative calculation: Take the partial derivatives of S with respect to the uniaxial compressive strength q, internal friction angle υ, and cohesion c respectively:

[0047]

[0048] Use the Newton-Raphson method for iterative solution. First, give the initial values of the formation mechanical parameters q 0 , υ 0 , c 0 , and then update the parameter values through the following iterative formula:

[0049]

[0050] where J is the Jacobian matrix, and its elements are

[0051] Step 4: Interpolation and visualization

[0052] Construct the Kriging equations. For the unknown point x0 on the heading face, assume its estimated value is a linear combination of the known point values Z(x i )(i = 1, 2, ···, n), that is where λ i is the weight coefficient.

[0053] To make the estimated value meet the unbiasedness and optimality (minimum error variance) conditions, the Kriging equations also need to be solved:

[0054] where μ is the Lagrange multiplier, and γ(x i - x j ) is the variogram value between the known points x i , x j , and γ(x i - x0) is the variogram value between the known point x i and the point x0 to be estimated.

[0055] Solve for the weight coefficients and perform interpolation estimation. Use linear algebra methods to solve the Kriging equations to obtain the values of the weight coefficients λ i and the Lagrange multiplier μ. Substitute the obtained weight coefficients λ i into the linear combination formula to calculate the estimated value of the geomechanical parameter of the unknown point x0 to be estimated. Repeat the steps of the Kriging equations, solving for the weight coefficients, and performing interpolation estimation for all the unknown points that need to be estimated on the heading face, so as to obtain the distribution of the geomechanical parameters of the entire heading face.

[0056] Through the above geomechanical model and algorithm, combined with data such as penetration force and displacement, calculate the mechanical parameters of the formation such as the compressive strength, internal friction angle, and cohesion of the formation. Use GIS to integrate the calculated geomechanical parameters with the geographic coordinate information of the heading face to construct a geographic data model containing geomechanical parameters and spatial location information. Using the GIS software platform, according to the integrated geographic data model, display the distribution of the geomechanical parameters in a variety of visualization methods. As Figure 3 -(1) shows, intuitively display the time distribution and change trend of the mechanical parameter (t) on the heading face through a coordinate curve graph; use Figure 3 -(2) to establish a hob tool area model of the heading face, and visually present the spatial differences of the geomechanical parameters in different colors and heights, so that construction personnel can observe the formation conditions of the heading face from different angles.

[0057] In summary, for the monitoring method of the mechanical penetration of the cutter head hob into the formation of the present invention, through the three-dimensional modeling function of the GIS software platform, the formation mechanical parameters are combined with the spatial position information to generate a three-dimensional formation model. In the three-dimensional model diagram, different formation mechanical parameters are visually presented through preset color coding and height differences, enabling construction personnel to clearly observe the distribution characteristics, change trends, and abnormal areas of the formation parameters. This intuitive visualization method not only improves the understanding efficiency of construction personnel but also provides strong support for formation prediction and decision-making during the tunneling process of the shield machine.

[0058] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A monitoring method for mechanically probing the ground using a cutter disc, characterized in that: The following steps are involved: Step 1: Data collection: Install force sensors and displacement sensors on the disc cutter of the shield machine to collect real-time resistance data F when the disc cuts the stratum. meas and displacement data s, the force sensor is installed at the connection between the hob and the cutter box, the displacement sensor is installed on the hob shaft component, and the measurement direction is consistent with the hob displacement direction; Step 2, mathematical model establishment: based on geotechnical mechanics theory, a functional relationship model between the roller cutter resistance F and the formation mechanical parameters is established, wherein the formation mechanical parameters include compressive strength q, internal friction angle υ and cohesion c, and the model associates the roller cutter resistance F with the formation parameters through elastic mechanics theory or Mohr-Coulomb strength criterion; Step 3, parameter inversion: construct the objective function using the least squares method, and use the Newton-Raphson iterative algorithm to invert the resistance data and displacement data F meas Perform inversion calculations to find the optimal solution for formation mechanics parameters; Step 4: Interpolation and visualization: The Kriging interpolation algorithm is used to perform spatial interpolation of the mechanical parameters of the tunnel face formation. The interpolation results are presented in a visualized form in combination with the GIS platform, presenting real-time dynamic information on the formation's compressive strength, internal friction angle, cohesion, and boulder distribution.

2. A monitoring method for mechanically probing the ground using a cutterhead roller according to claim 1, characterized in that: The data collection frequency described in step one is dynamically adjusted according to the tunneling speed of the shield machine and the changes in the strata: when the tunneling speed is higher than the preset threshold or the strata change amplitude exceeds the set range, the collection frequency is 50-100 times / second; when the tunneling speed is lower than the preset threshold and the strata are stable, the collection frequency is 5-30 times / second.

3. The method for monitoring the formation by mechanical penetration of a cutter disc according to claim 1 is characterized in that: The functional relationship model between the roller resistance F and the formation parameters in step 2 is: F = g(q,υ,c,s), where g is a nonlinear function based on the roller geometry, cutting method and plastic deformation characteristics of the formation.

4. The method for monitoring the formation by mechanical penetration of a cutterhead according to claim 1 is characterized in that: The objective function in step 3 is: Among them, F pred,i To predict the resistance value for the model, the formation parameters are optimized through Jacobian matrix iteration.

5. The method for monitoring the formation by mechanical penetration of a cutter disc according to claim 1 is characterized in that: The Kriging interpolation algorithm described in step 4 solves the weight coefficient λ by constructing the Kriging equation system i , and combined with the variation function, the formation mechanical parameters of unknown points at the tunnel face are spatially estimated.

6. The method for monitoring the formation by mechanical penetration of a cutter head according to claim 1, characterized in that: The visualization form includes a coordinate curve graph and a three-dimensional model graph, wherein the coordinate curve graph is used to show the changing trend of the formation mechanical parameters over time; the three-dimensional model graph intuitively presents the spatial distribution of the formation mechanical parameters through color and height differences.

7. The method for monitoring the formation by mechanical penetration of a cutter head according to claim 1, characterized in that: The roller cutter feeler unit comprises a feeler rod and a feeler head, wherein the feeler rod is made of a high-strength alloy material and the surface of the feeler head is provided with a wear-resistant coating.

8. The method for monitoring the formation by mechanical penetration of a cutterhead according to claim 1, characterized in that: The sensor data is subjected to noise suppression by a Kalman filter algorithm to improve the accuracy of formation parameter inversion.

Images