Guiding device and method for metro engineering shield measurement

Abstract

The invention relates to the technical field of shield measurement guiding, in particular to a guiding device and method for subway engineering shield measurement. The method comprises the steps that whether a shield tunneling machine enters a composite geologic structure of an upper soft soil layer and a lower hard rock layer or not is judged based on a composite stratum recognition index determined by attitude deviation parameters and torque fluctuation characteristics; determining a hardness proportionality coefficient of the composite geological structure based on the extension length of the interface of the composite geological structure, and generating a first guide adjustment strategy; generating a second guide adjustment strategy based on the volatility; and whether the settlement control effect is qualified or not is determined based on the uniformity characterization value of the filling compactness of the tunnel wall post-grouting in the tunneled area, and the preset stratum index is optimized. The device comprises a total station, a rearview prism, a laser target, a plurality of target prisms, a guiding calculation module, a geological structure judgment module, an interface determination module and a guiding adjustment module. According to the invention, the guiding precision of the automatic guiding system based on the total station is improved.

Description

Technical Field

[0001] This invention relates to the field of shield tunneling measurement guidance technology, and in particular to a guidance device and method for shield tunneling measurement in subway engineering. Background Technology

[0002] In subway tunnel shield construction, the composite geological structure of soft upper layer and hard lower layer is a typical complex and unfavorable stratum, posing extremely high requirements for shield tunneling attitude and guidance control. Currently, most mainstream shield tunneling automatic guidance systems use a total station as the core measuring device, combined with an airborne target and prism to achieve spatial positioning and attitude calculation of the shield machine. This can meet basic guidance requirements in homogeneous strata. However, when tunneling in composite strata of soft upper layer and hard lower layer, the asymmetric reaction force generated by the lower hard rock on the cutterhead can easily cause drastic changes in shield machine pitch, roll, and axis deviation. The upper soft strata cannot provide stable constraints, further exacerbating attitude fluctuations. Such dynamic attitude changes can easily lead to poor visibility between the total station and the airborne target / prism, resulting in discontinuities or deviations in measurement data. Simultaneously, the attitude calculation and correction response speed of traditional guidance systems cannot match the rapid attitude changes caused by geological abrupt changes, leading to reduced guidance accuracy and delayed correction. This makes continuous and stable automatic guidance impossible, easily causing engineering risks such as tunnel axis exceeding limits and uneven surface settlement, and is ill-suited to the actual needs of high-precision automatic guidance for subway shield tunnels under complex geological conditions.

[0003] Chinese Patent Application Publication No. CN103471569A discloses an automatic guidance measurement target and system for tunnel boring machines (TBMs). The target is a target prism located inside the TBM, capable of moving along a fixed linear coordinate system. The spatial relationship between this linear coordinate system and the TBM's axis is known, and the target prism can stop at any position along this line. The system includes the target and a total station with automatic identification function located behind the TBM. This invention moves the target prism along a linear track, stopping at different positions sequentially. The total station observes the prism at each different position, obtaining spatial position information for multiple different stopping points. Simultaneously, a dual-axis inclinometer (INCL) measures the roll angle and pitch angle, transmitting this information back to the system. This invention is applicable to various conditions of tunnel boring machine construction and can minimize or even eliminate the impact of total station angle measurement errors on the accuracy of the measurement results, possessing self-verification and correction capabilities.

[0004] The existing technology still has the following problems: the existing shield tunneling automatic guidance system based on total station is prone to poor visibility, decreased measurement accuracy, and lag in attitude calculation and correction response due to drastic changes in shield attitude in composite strata with soft upper and hard lower layers. It cannot achieve continuous, stable and high-precision automatic guidance. Summary of the Invention

[0005] Therefore, the present invention provides a guiding device and method for shield tunneling measurement in subway engineering, which overcomes the problem that the existing shield tunneling automatic guidance system based on total station is prone to poor visibility, decreased measurement accuracy, and delayed attitude calculation and correction response in composite strata with soft upper and hard lower layers, resulting in low guidance accuracy.

[0006] To achieve the above objectives, on the one hand, the present invention provides a guiding method for shield tunneling measurement in subway engineering, characterized in that it includes: The tunnel boring machine (TBM) advances along the design axis according to the guidance results of the guiding device. The attitude deviation parameters of the front shield and the torque fluctuation characteristics of the cutterhead are obtained in real time during the tunneling process. The attitude deviation parameters include the change in horizontal deviation of the cut and the change in vertical deviation of the cut. Based on the attitude deviation parameters and the torque fluctuation characteristics, a composite stratum identification index is determined. Based on the comparison between the composite stratum identification index and the preset stratum index, it is determined whether the tunnel boring machine has entered a composite geological structure consisting of an upper soft soil layer and a lower hard rock layer. In response to the tunnel boring machine entering a composite geological structure with a soft upper layer and a hard lower layer, a geological radar detection profile map within a preset range in front of the tunnel face is obtained. Based on the extension length of the interface of the composite geological structure, the soft-hard ratio coefficient of the composite geological structure is determined. Based on the soft-hard ratio coefficient, a first guiding adjustment strategy is generated to adjust the thrust difference between the upper and lower cylinders of the tunnel boring machine. Based on the first guidance adjustment strategy, a tunneling specific energy curve of the tunnel boring machine is constructed, and a second guidance adjustment strategy for correcting the first guidance adjustment strategy is generated based on the volatility of the tunneling specific energy curve within a preset sliding window. After the tunneling of the preset section is completed, the settlement control effect is determined based on the uniformity of the filling density of the grouting behind the tunnel wall in the already excavated area. The preset stratum index is then optimized based on the unqualified conditions.

[0007] Furthermore, the composite strata identification index is a weighted sum of the quantum index of horizontal deviation change of the cut, the quantum index of vertical deviation change of the cut, and the sub-index of torque fluctuation amplitude matching.

[0008] Furthermore, the process of determining whether a tunnel boring machine has entered a complex geological structure consisting of an upper soft soil layer and a lower hard rock layer based on the composite stratum identification index includes: The composite stratigraphic identification index is compared with a preset stratigraphic index; Based on the comparison result that the composite stratum identification index is greater than the preset stratum index, it is determined that the tunnel boring machine has entered a composite geological structure.

[0009] Furthermore, when the tunnel boring machine enters a composite geological structure with a soft upper layer and a hard lower layer, the process of determining the interface of the composite geological structure based on the ground-penetrating radar profile includes: The ground-penetrating radar profile is divided into several horizontal strips at equal intervals along the depth direction, and the average reflection amplitude of each horizontal strip is determined. Using the first horizontal strip below the ground surface as a reference, calculate the amplitude difference of the average reflection amplitude of two adjacent horizontal strips from top to bottom; The horizontal stripe whose amplitude difference first exceeds the preset amplitude is identified as the interface of the composite geological structure.

[0010] Furthermore, the process of determining the hardness ratio of the composite geological structure based on the extension length of the interface includes: A cross-sectional coordinate system is established with the center of the shield machine cut as the origin. The circular cut cross-section of the shield machine is divided by a horizontal line corresponding to the burial depth of the interface. The area of ​​the lower part of the divided circular cut cross-section is taken as the area of ​​the hard rock layer. The ratio of the area of ​​the hard rock layer to the total area of ​​the circular cut cross-section is determined as the basic hardness-softness ratio coefficient. The extension length of the interface along the tunneling direction is obtained, and the length ratio of the extension length to the preset length is determined as the extension length weighting coefficient. The product of the extension length weighting coefficient and the basic soft-hard ratio coefficient is determined as the soft-hard ratio coefficient.

[0011] Furthermore, the process of generating the first guidance adjustment strategy based on the soft-hard ratio coefficient includes: The soft-hard ratio coefficients are compared with preset ratio coefficients respectively; Based on the comparison results between the soft and hard ratio coefficients and the preset ratio coefficients, the thrust difference adjustment coefficient of the upper and lower hydraulic cylinders of the tunnel boring machine is determined.

[0012] Furthermore, the process of generating a second guidance adjustment strategy for correcting the first guidance adjustment strategy based on the volatility of the tunneling specific energy curve within a preset sliding window includes: Based on the tunneling specific energy curve, the percentage of the average value and standard deviation of the tunneling specific energy within a preset sliding window is determined as the volatility of the tunneling specific energy. The volatility is compared with the preset volatility; Based on the comparison between the volatility and the preset volatility, a second guidance adjustment strategy is generated to modify the first guidance adjustment strategy.

[0013] Furthermore, the process of determining whether the settlement control effect is qualified based on the homogeneity characterization value includes: The uniformity characterization value is compared with a preset characterization value; Based on the comparison result that the uniformity characterization value is greater than the preset characterization value, it is determined that the settlement control effect is unqualified.

[0014] Furthermore, under the condition that the settlement control effect is unsatisfactory, the process of optimizing the preset formation index includes: The difference between the uniformity characterization value and the preset characterization value is used to obtain the characterization difference value; Based on the comparison results between the characterization difference and the preset characterization difference, several index optimization coefficients are set to optimize the preset formation index.

[0015] On the other hand, the present invention also provides a guiding device for shield tunneling measurement in subway engineering, comprising: A total station is a measuring bracket mounted on the side wall of a tunnel segment to measure the three-dimensional coordinates of a target point. A rearview prism, which is mounted on the tunnel segment, is used to provide an azimuth reference for the total station. A laser target is installed inside the front shield of the tunnel boring machine to receive the laser beam emitted by the total station; Several target prisms are installed inside the front shield of the tunnel boring machine to provide observation targets for the total station. The guidance calculation module is used to calculate in real time the attitude deviation parameters of the front shield and the torque fluctuation characteristics of the cutterhead during the tunneling process of the tunnel boring machine; The geological structure determination module is used to determine whether the tunnel boring machine has entered a composite geological structure of upper soft soil layer and lower hard rock layer based on the composite stratum identification index determined by the attitude deviation parameters and the torque fluctuation characteristics, and the comparison result with the preset stratum index. It also determines whether the settlement control effect is qualified based on the uniformity characterization value of the filling density of the grouting behind the tunnel wall in the excavated area, and optimizes the preset stratum index based on the unqualified conditions. The interface determination module, in response to the tunnel boring machine entering a composite geological structure with a soft upper layer and a hard lower layer, is used to determine the interface of the composite geological structure based on the geological radar detection profile, and to determine the soft-hard ratio coefficient of the composite geological structure based on the extension length of the interface. The guidance adjustment module is used to generate a first guidance adjustment strategy based on the soft-hard ratio coefficient to adjust the thrust difference between the upper and lower cylinders of the tunnel boring machine, and to generate a second guidance adjustment strategy to correct the first guidance adjustment strategy based on the fluctuation rate of the tunneling specific energy curve of the tunnel boring machine within a preset sliding window.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: In composite strata with a soft upper layer and a hard lower layer, the significant differences in the mechanical properties of the upper and lower soil and rock layers lead to asymmetric reaction forces on the cutterhead caused by the high resistance of the lower hard rock and the weak constraint of the upper soft soil, which makes it difficult to provide reverse bearing capacity. These two factors together cause shield machine head lifting, stress imbalance, and sudden attitude changes. Simultaneously, dynamic changes in the strata can easily lead to deterioration of the total station's visibility. Traditional guidance systems, due to their single detection dimension and fixed correction strategies, often suffer from strata misjudgment and response lag, resulting in a sharp drop in guidance accuracy, tunnel axis deviation, and uncontrolled settlement, among other engineering risks. This invention constructs a guidance system based on strata identification, breaking through the limitations of traditional guidance systems through multi-dimensional data fusion, adaptive strategy adjustment, and real-time operational condition calibration. It provides a systematic solution for shield machine guidance under complex geological conditions, thereby improving the guidance accuracy of total station-based automatic guidance systems.

[0017] Furthermore, this invention constructs a composite stratum identification index, integrating the changes in horizontal / vertical deviation of the cutterhead with the characteristics of cutterhead torque fluctuations. By combining weight allocation, it emphasizes the vertical deviation weight, which is most sensitive to composite strata, accurately capturing the attitude changes and torque fluctuations caused by alternating soft and hard cutting. Simultaneously, it uses ground-penetrating radar to clarify stratigraphic interface information, providing intuitive and quantitative verification of composite stratum boundaries and distribution characteristics, enabling rapid and accurate identification of composite geological structures with soft upper layers and hard lower layers. This ensures the accuracy of the stratum perception of the guidance system from the source, providing reliable basic data support for subsequent guidance adjustments and avoiding inaccuracies in correction due to stratum misjudgment, thereby further improving the guidance accuracy of the total station-based automatic guidance system.

[0018] Furthermore, this invention comprehensively calculates the soft-hard ratio coefficient based on the interface of the composite strata, the proportion of hard rock at the cut, and the extension length of the interface. This generates a first guiding adjustment strategy adapted to the strata characteristics, precisely adjusting the thrust difference between the upper and lower hydraulic cylinders of the tunnel boring machine. This allows the correction torque to match the strata disturbance torque in real time, effectively counteracting the head-up tendency and avoiding attitude oscillations, segment misalignment, and excavation face instability caused by thrust mismatch. Through dynamic quantitative determination of the soft-hard ratio coefficient, precise adaptation of the correction strategy to the composite geological conditions is achieved, ensuring the effectiveness of the guiding system's correction and further improving the guiding accuracy of the total station-based automatic guiding system.

[0019] Furthermore, this invention introduces tunneling specific energy curve and sliding window volatility analysis to verify the matching degree between the correction strategy and actual working conditions using the dynamic fluctuation characteristics of tunneling energy consumption. When the specific energy volatility exceeds a preset threshold, the thrust difference adjustment coefficient is modified. This can moderately weaken the excessive correction torque while ensuring the correction effect, avoiding repeated attitude reversals, cutterhead stress impacts, and abnormal energy consumption caused by excessive correction strategy. This effectively balances the correction force and tunneling stability, thereby further improving the guidance accuracy of the automatic guidance system based on the total station. Attached Figure Description

[0020] Figure 1 This is a flowchart of a guiding method for shield tunneling measurement in subway engineering, according to an embodiment of the present invention. Figure 2 This is a flowchart illustrating how to determine whether a tunnel boring machine has entered a composite geological structure consisting of an upper soft soil layer and a lower hard rock layer, according to an embodiment of the present invention. Figure 3 This is a flowchart illustrating how to determine whether the settlement control effect is satisfactory in an embodiment of the present invention. Figure 4 This is a structural block diagram of a guide device for shield tunneling measurement in subway engineering, according to an embodiment of the present invention. Detailed Implementation

[0021] 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.

[0022] 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.

[0023] It should 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.

[0024] Please see Figures 1-3 As shown, Figure 1 This is a flowchart of a guiding method for shield tunneling measurement in subway engineering, according to an embodiment of the present invention. Figure 2 This is a flowchart illustrating how to determine whether a tunnel boring machine has entered a composite geological structure consisting of an upper soft soil layer and a lower hard rock layer, according to an embodiment of the present invention. Figure 3 This is a flowchart for determining whether the settlement control effect is qualified in an embodiment of the present invention.

[0025] The present invention provides a guiding method for shield tunneling measurement in subway engineering, comprising: Step S1: The tunnel boring machine (TBM) advances along the design axis according to the guidance results of the guiding device. The attitude deviation parameters of the front shield and the torque fluctuation characteristics of the cutterhead are obtained in real time during the tunneling process. The attitude deviation parameters include the change in horizontal deviation of the cut and the change in vertical deviation of the cut. Step S2: Determine the composite stratum identification index based on the attitude deviation parameters and the torque fluctuation characteristics. Based on the comparison result between the composite stratum identification index and the preset stratum index, determine whether the tunnel boring machine has entered a composite geological structure of upper soft soil layer and lower hard rock layer. Step S3: In response to the tunnel boring machine entering a composite geological structure with soft upper part and hard lower part, a geological radar detection profile map within a preset range in front of the tunnel face is obtained. Based on the extension length of the interface of the composite geological structure, the soft-hard ratio coefficient of the composite geological structure is determined. Based on the soft-hard ratio coefficient, a first guiding adjustment strategy is generated to adjust the thrust difference between the upper and lower cylinders of the tunnel boring machine. Step S4: Construct the tunneling energy curve of the tunnel boring machine based on the first guidance adjustment strategy, and generate a second guidance adjustment strategy to correct the first guidance adjustment strategy based on the volatility of the tunneling energy curve within a preset sliding window. Step S5: After completing the excavation of the preset section, determine whether the settlement control effect is qualified based on the uniformity characterization value of the filling density of the grouting behind the tunnel wall in the excavated area, and optimize the preset stratum index based on the unqualified condition.

[0026] Specifically, the composite stratum identification index is a weighted sum of the quantum index of horizontal deviation change of the cut, the quantum index of vertical deviation change of the cut, and the sub-index of torque fluctuation amplitude matching. The weight coefficient of the quantum index of horizontal deviation change of the cut is 0.2, the weight coefficient of the quantum index of vertical deviation change of the cut is 0.5, and the weight coefficient of the sub-index of torque fluctuation amplitude matching is 0.3. The weight coefficients are set based on the fact that vertical attitude deviation is most sensitive to stratum changes in soft upper and hard lower strata, so it is given the highest weight to improve the identification accuracy.

[0027] Specifically, the process for determining the quantum index of the change in the horizontal deviation of the cut includes: The change in the horizontal deviation of the incision is compared with a preset horizontal change. Based on the comparison result that the change in the horizontal deviation of the incision is greater than the first preset horizontal change, the value of the quantum index of the change in the horizontal deviation of the incision is determined to be 2. Based on the comparison result that the change in the horizontal deviation of the cut is less than or equal to the first preset horizontal change and greater than or equal to the second preset horizontal change, the quantum index of the change in the horizontal deviation of the cut is determined to be 1.5. Based on the comparison result that the change in the horizontal deviation of the incision is less than the second preset horizontal change, the quantum index of the change in the horizontal deviation of the incision is determined to be 1.

[0028] Specifically, the first preset horizontal change is 6 mm / ring, and the second preset horizontal change is 3 mm / ring. However, the above values ​​are not limited to these, and those skilled in the art can also choose values ​​according to actual needs.

[0029] Specifically, the change in horizontal deviation of the cut refers to the distance by which the center of the cutterhead at the front of the tunnel boring machine deviates from the design axis in the horizontal direction within a unit distance of 1 ring, while the change in vertical deviation refers to the distance by which the center of the cutterhead at the front of the tunnel boring machine deviates from the design axis in the vertical direction within a unit distance of 1 ring.

[0030] Specifically, the process of determining the quantum index of vertical deviation change includes: The vertical deviation change is compared with the preset vertical deviation change. Based on the comparison result that the vertical deviation change is greater than the first preset vertical deviation change, the value of the vertical deviation change quantum index is determined to be 2.2; Based on the comparison result that the vertical deviation change is less than or equal to the first preset vertical deviation change and greater than or equal to the second preset vertical deviation change, the value of the vertical deviation change quantum index is determined to be 1.6. Based on the comparison result that the vertical deviation change is less than the second preset vertical deviation change, the value of the vertical deviation change quantum index is determined to be 1.

[0031] Specifically, the first preset vertical change value is 5mm / ring, and the second preset vertical change value is 2mm / ring. However, the above values ​​are not limited to these, and those skilled in the art can also choose values ​​according to actual needs.

[0032] Specifically, the process of determining the torque fluctuation amplitude matching sub-index includes: The fluctuation range of the real-time torque is compared with the preset torque fluctuation range; Based on the comparison result that the fluctuation amplitude is greater than or equal to the first preset torque fluctuation amplitude and less than or equal to the second preset torque fluctuation amplitude, the value of the torque fluctuation amplitude matching sub-index is determined to be 1.2. Based on the comparison result that the fluctuation amplitude is less than the first preset torque fluctuation amplitude or greater than the second preset torque fluctuation amplitude, the value of the torque fluctuation amplitude matching sub-index is determined to be 0.8.

[0033] Specifically, the first preset torque fluctuation range is -10%, and the second preset torque fluctuation range is 10%. However, the above values ​​are not limited to these, and those skilled in the art can also choose values ​​according to actual needs.

[0034] Specifically, fluctuation range refers to the percentage of the difference between real-time torque and average torque relative to the average torque.

[0035] Specifically, in subway engineering, the presence of complex geological formations with soft upper layers and hard lower layers has a significant impact on the attitude and directional control of tunnel boring machines (TBMs). The high resistance to fracturing of the lower hard rock generates a concentrated upward reaction force on the cutterhead, while the easily compressible upper soft soil offers little effective counter-restraint. Together, these forces create an upward rotational torque, causing the TBM head to tend to lift. Simultaneously, the lower section jacks require higher hydraulic pressure to overcome the resistance of the hard rock, resulting in a much greater thrust than the upper section, further exacerbating the upward rotational torque and reinforcing the head's lifting tendency. Furthermore, when the cutterhead cuts through unevenly distributed strata, the hard rock contact area experiences greater stress than the soft soil area, leading to an overall imbalance that can cause the TBM to deviate towards the side with less stress. Combined with the tendency of the upper soft soil to collapse and the relatively stable lower hard rock, the overall poor stability of the excavation face further amplifies the risk of loss of TBM attitude control, ultimately causing the TBM's tunneling direction to deviate from the design axis. The quantum index of horizontal deviation variation in the cutterhead characterizes the rate of change of horizontal attitude deviation, enabling rapid detection of sudden horizontal offsets caused by asymmetric forces on the cutterhead within complex geological formations. The quantum index of vertical deviation variation in the cutterhead reflects the rate of change of vertical attitude deviation in the shield cutterhead, providing early warning of nose-up tendencies caused by soft-over-hard geological formations. The torque fluctuation amplitude matching sub-index characterizes the matching relationship between the degree of cutterhead torque fluctuation and the characteristics of the complex geological formations. Alternating cutting of soft and hard surfaces within complex formations causes drastic fluctuations in cutterhead torque, and the amplitude of these fluctuations is positively correlated with the difference in the hardness of the geological formations. By allocating appropriate weights and highlighting the quantum index of vertical deviation variation in the cutterhead, which is most sensitive to complex geological formations, a multi-dimensional parameter-based comprehensive determination of whether the shield has entered a complex geological structure layer can effectively reduce the misjudgment rate of single-parameter determinations and improve the accuracy of geological formation identification.

[0036] Specifically, the process of determining whether a tunnel boring machine has entered a complex geological structure consisting of an upper soft soil layer and a lower hard rock layer, based on the comparison between the composite stratum identification index and the preset stratum index, includes: The composite stratigraphic identification index is compared with a preset stratigraphic index; Based on the comparison result that the composite stratum identification index is greater than the preset stratum index, it is determined that the tunnel boring machine has entered a composite geological structure. Based on the comparison result that the composite stratum identification index is less than or equal to the preset stratum index, it is determined that the tunnel boring machine has not entered the composite geological structure.

[0037] Specifically, the preset stratigraphic index is set to a range of [1.4, 1.6], and in this embodiment of the invention, 1.5 is preferred.

[0038] Specifically, when a tunnel boring machine enters a composite geological structure that is soft on top and hard on the bottom, the process of determining the interface of the composite geological structure based on the ground-penetrating radar profile includes: The ground-penetrating radar profile is divided into several horizontal strips at equal intervals along the depth direction, and the average reflection amplitude of each horizontal strip is determined. Using the first horizontal strip below the ground surface as a reference, calculate the amplitude difference of the average reflection amplitude of two adjacent horizontal strips from top to bottom; The horizontal stripe whose amplitude difference first exceeds the preset amplitude is identified as the interface of the composite geological structure; The vertical distance from the center of the horizontal strip containing the interface to the ground surface is determined as the interface burial depth.

[0039] Specifically, the preset amplitude is 50, and the depth direction refers to the direction downward from the ground surface.

[0040] Specifically, the process of determining the geological radar detection profile includes: transmitting high-frequency electromagnetic pulses into a preset range of 3 meters in front of the tunnel face through a multi-channel radar antenna deployed below the shield of the tunnel boring machine, and receiving the reflected echo signals; after denoising, offset repositioning and amplitude attribute extraction of the echo signals, a geological radar detection profile is generated. The generation process is existing technology and will not be described in detail.

[0041] Specifically, the process of determining the hardness ratio of the composite geological structure based on the extension length of the interface includes: A cross-sectional coordinate system is established with the center of the shield machine cut as the origin. The circular cut cross-section of the shield machine is divided by a horizontal line corresponding to the burial depth of the interface. The area of ​​the lower part of the divided circular cut cross-section is taken as the area of ​​the hard rock layer. The ratio of the area of ​​the hard rock layer to the total area of ​​the circular cut cross-section is determined as the basic hardness-softness ratio coefficient. The extension length of the interface along the tunneling direction is obtained, and the length ratio of the extension length to the preset length is determined as the extension length weighting coefficient. The product of the extension length weighting coefficient and the basic soft-hard ratio coefficient is determined as the soft-hard ratio coefficient.

[0042] Specifically, the preset length refers to the length of the tunnel boring machine itself.

[0043] Specifically, the process of generating the first guidance adjustment strategy based on the soft-hard ratio coefficient includes: The soft-hard ratio coefficients are compared with preset ratio coefficients respectively; Based on the comparison results between the soft and hard ratio coefficients and the preset ratio coefficients, the thrust difference adjustment coefficient of the upper and lower hydraulic cylinders of the tunnel boring machine is determined.

[0044] Specifically, based on the comparison result that the soft-hard ratio coefficient is greater than the first preset ratio coefficient and less than or equal to the second preset ratio coefficient, it is determined that the thrust difference is adjusted by the first thrust difference adjustment coefficient. Based on the comparison result that the soft-hard ratio coefficient is greater than the second preset ratio coefficient and less than or equal to the third preset ratio coefficient, it is determined that the thrust difference is adjusted by the second thrust difference adjustment coefficient. Based on the comparison result that the soft-hard ratio coefficient is greater than the third preset ratio coefficient and less than or equal to the fourth preset ratio coefficient, it is determined that the thrust difference is adjusted by the third thrust difference adjustment coefficient.

[0045] Specifically, the first preset proportional coefficient is 0, the second preset proportional coefficient is 0.3, the third preset proportional coefficient is 0.6, and the fourth preset proportional coefficient is 1; the first thrust difference adjustment coefficient is 1.3, the second thrust difference adjustment coefficient is 1.7, and the third thrust difference adjustment coefficient is 2.2. However, the above values ​​are not limited to these, and those skilled in the art can also choose values ​​according to actual needs.

[0046] Specifically, the larger the thrust difference adjustment coefficient, the greater the target thrust difference between the upper and lower cylinders, so as to counteract the nose pitching trend with a stronger corrective torque.

[0047] Specifically, the process of adjusting the thrust difference using the thrust difference adjustment coefficient to obtain the target thrust difference is as follows: The total thrust benchmark value of the tunnel boring machine (TBM) in a single homogeneous stratum, the benchmark thrust difference between the upper and lower cylinders, and the hydraulic pressure-thrust conversion coefficient corresponding to the single-ring advance length are obtained. The benchmark thrust difference is the difference between the total thrust of the upper cylinder and the total thrust of the lower cylinder required to maintain horizontal tunneling of the TBM in a single homogeneous stratum. It is usually a small positive value used to offset the slight downward tendency caused by the TBM's own weight. The hydraulic pressure-thrust conversion coefficient is determined by the inherent parameters of the TBM, such as the cylinder diameter and number of cylinders, and can be directly obtained or calculated by those skilled in the art based on the equipment parameters. The product of the sum of 1 and the soft-hard ratio coefficient, the benchmark thrust difference, and the thrust difference adjustment coefficient is the target thrust difference.

[0048] Specifically, the sum of the total thrust reference value and the target thrust difference is divided by 2, and the quotient is the target thrust value of the upper cylinder; the difference between the total thrust reference value and the target thrust difference is divided by 2, and the quotient is the target thrust value of the lower cylinder.

[0049] Specifically, the target thrust value is converted into a hydraulic pressure adjustment value through a hydraulic pressure-thrust conversion coefficient to adjust the actual thrust of the corresponding hydraulic cylinder. This is existing technology and will not be elaborated further.

[0050] Specifically, the hard rock ratio coefficient is determined by the proportion of hard rock in the cut-out section and the extension length of the interface. The larger the coefficient, the higher the proportion of hard rock in the lower part, the more continuous the distribution of the composite strata, the stronger the upward concentrated reaction force on the cutterhead, the greater the tunneling resistance that the lower hydraulic cylinder needs to overcome, and the more significant the resulting upward rotational torque and the head-up tendency. In strata with soft upper and hard lower, the reaction force of the lower hard rock and the large thrust of the lower hydraulic cylinder will jointly form an upward rotational torque, pushing the shield machine head up and causing the tunneling direction to deviate from the design axis. Only by adjusting the thrust difference between the upper and lower hydraulic cylinders, so that the thrust of the upper hydraulic cylinder is greater than that of the lower hydraulic cylinder, can a corrective torque opposite to the upward torque be formed, thus offsetting the attitude interference caused by the hard rock, suppressing the head-up, and correcting the horizontal and vertical deviations. If the thrust difference is not adjusted according to the hardness ratio coefficient and only a fixed thrust difference is used, problems of insufficient or excessive correction are likely to occur: when the proportion of hard rock is small, an excessively large thrust difference will cause the shield to sag and fluctuate in attitude; when the proportion of hard rock is large, an excessively small thrust difference will not be able to offset the pitching moment, leading to loss of attitude control. Dynamically adapting the thrust difference according to the hardness ratio coefficient can make the correction moment accurately match the disturbance moment generated by the stratum, reduce the risk of segment misalignment, damage and instability of the excavation face, and continuously constrain the tunneling direction within the design axis range, thereby improving the stability and guiding accuracy of shield tunneling in dangerous composite strata with soft upper and hard lower layers.

[0051] Specifically, tunneling energy ratio refers to the energy consumed by a tunnel boring machine (TBM) per unit volume of rock and soil. The preset sliding window value is 5 rings, but this value is not limited to this; those skilled in the art can dynamically adjust it according to the construction conditions. Using the TBM tunneling ring number as the abscissa and the single-ring tunneling energy ratio corresponding to that ring number as the ordinate, a continuous curve of tunneling energy ratio changing with the number of tunneling rings is continuously collected and plotted according to the sliding window; this is the tunneling energy ratio curve.

[0052] Specifically, the process of generating a second guidance adjustment strategy to correct the first guidance adjustment strategy based on the volatility of the tunneling specific energy curve within a preset sliding window includes: Based on the tunneling specific energy curve, the percentage of the average value and standard deviation of the tunneling specific energy within a preset sliding window is determined as the volatility of the tunneling specific energy. The volatility is compared with the preset volatility; Based on the comparison between the volatility and the preset volatility, a second guidance adjustment strategy is generated to modify the first guidance adjustment strategy.

[0053] Specifically, based on the comparison result that the volatility is less than or equal to the first preset volatility, the thrust difference adjustment coefficient is optimized by the first thrust difference correction coefficient. Based on the comparison result that the volatility is greater than the first preset volatility and less than or equal to the second preset volatility, it is determined that the thrust difference adjustment coefficient is optimized with the second thrust difference correction coefficient. Based on the comparison result that the volatility is greater than the second preset volatility, the thrust difference adjustment coefficient is determined to be optimized by the third thrust difference correction coefficient.

[0054] Specifically, the first preset volatility is 5%, the second preset volatility is 10%, the first thrust difference correction coefficient is 1, the second thrust difference correction coefficient is 0.9, and the third thrust difference correction coefficient is 0.8. However, the above values ​​are not limited to these, and those skilled in the art can adjust them according to the actual needs of the project.

[0055] Specifically, the corrected thrust difference adjustment coefficient is the product of the original thrust difference adjustment coefficient and the corresponding thrust difference correction coefficient.

[0056] Specifically, tunneling specific energy is the energy consumption per unit volume of soil being tunneled. The higher its volatility, the more severe the fluctuations in the tunnel boring machine's thrust, torque, and attitude, and the more unstable the force state of the cutterhead cutting and hydraulic cylinder propulsion. This directly indicates that the current correction strategy determined by the thrust difference adjustment coefficient is mismatched with the actual strata and attitude. The thrust difference adjustment coefficient directly determines the magnitude of the thrust difference between the upper and lower hydraulic cylinders. An excessively large coefficient will lead to excessive correction torque. While offsetting the uplift torque of the soft upper and hard lower strata, it will also form a reverse overload torque, causing repeated oscillations in the shield's attitude, sudden changes in cutterhead force, and increased disturbance at the excavation face. Ultimately, this manifests as a significant jump in tunneling specific energy and a marked increase in volatility. By reducing the thrust difference adjustment coefficient by decreasing the volatility, the thrust difference between the upper and lower cylinders can be appropriately reduced, the strength of the correction torque can be weakened, and attitude reversal, force impact and abnormal energy consumption caused by excessive correction can be avoided. This allows the tunnel boring machine to achieve a balance between effectively suppressing head-up and smooth advancement, so that the tunneling specific energy tends to be stable and the volatility falls back to a reasonable range. In this way, while ensuring the attitude correction effect on the composite strata, the continuity of the tunneling process and the accuracy of directional control can be improved.

[0057] Specifically, the uniformity characterization value of the grouting density behind the tunnel wall in the excavated area refers to the coefficient of variation of the grouting density measured at each detection point behind the tunnel wall in the excavated section.

[0058] Specifically, the density of the grout filling behind the tunnel wall can be determined using ground-penetrating radar. The layout of the detection points can be divided into detection zones every 3 rings. Each detection zone is further divided into 8 sub-regions: top, bottom, left, right, upper left, upper right, lower left, and lower right. The center of each sub-region serves as one detection point, and each detection point corresponds to one density detection value. The specific details are not limited.

[0059] Specifically, the process of determining whether the settlement control effect is satisfactory based on the uniformity characterization value includes: The uniformity characterization value is compared with a preset characterization value; Based on the comparison results of the uniformity characterization value being less than or equal to the preset characterization value, the settlement control effect is determined to be qualified; Based on the comparison result that the uniformity characterization value is greater than the preset characterization value, it is determined that the settlement control effect is unqualified.

[0060] Specifically, the preset representation value is 15%, but the above value is not limited to this, and those skilled in the art can also choose a value according to actual needs.

[0061] Specifically, the function of tunnel wall grouting is to fill the voids between the lining and the surrounding rock, providing uniform support to the surrounding rock, inhibiting rock relaxation, deformation, and collapse, and controlling ground settlement at its source. The quality of grouting directly determines the settlement control effect. If the grouting density is uniform, the surrounding rock can obtain continuous and balanced support, and the ground deformation is stable, effectively avoiding local settlement, uneven settlement, and excessive settlement. Conversely, if the grouting density is uneven, with voids and loose areas in some places, the surrounding rock will experience local instability and stress concentration, which will lead to sudden settlement and differential settlement, directly causing settlement control failure. Crucially, the accuracy of the shield tunneling measurement and guidance directly affects the uniformity of the grouting behind the wall. Accurate shield tunneling measurement and guidance ensures that the tunnel lining is installed according to the design axis and that the gaps behind the wall between the lining and the surrounding rock are evenly distributed, providing a foundation for uniform grout filling. If the shield tunneling measurement and guidance deviation is too large, it will lead to the lining installation being tilted and the gaps behind the wall being of varying widths. During grouting, the grout tends to accumulate in the wide gaps and be insufficiently filled in the narrow gaps, directly causing an increase in the dispersion of the filling density, which in turn leads to uneven settlement. If a section experiences local settlement exceeding the standard, it often indicates that there is a deviation in the shield tunneling measurement and guidance in that section.

[0062] Specifically, under the condition that the settlement control effect is unsatisfactory, the process of optimizing the preset formation index includes: The difference between the uniformity characterization value and the preset characterization value is used to obtain the characterization difference value; Based on the comparison results between the characterization difference and the preset characterization difference, several index optimization coefficients are set to optimize the preset formation index.

[0063] Specifically, based on the comparison result that the characterization difference is greater than the preset characterization difference, it is determined to reduce the preset formation index by the first index optimization coefficient; Based on the comparison results of the characterization difference being less than or equal to the preset characterization difference, it is determined that the preset formation index is reduced by the second index optimization coefficient.

[0064] Specifically, the preset value of the representation difference is 3%, the value of the first index optimization coefficient is 0.9, and the value of the second index optimization coefficient is 0.95. However, the above values ​​are not limited to these, and those skilled in the art can also choose values ​​according to actual needs.

[0065] Please see Figure 4 As shown, it is a structural block diagram of a guide device for shield tunneling measurement in subway engineering, according to an embodiment of the present invention.

[0066] This invention also provides a guiding device for tunnel boring machine (TBM) measurement in subway engineering, comprising: A total station is set on a special measuring bracket on the side wall of a pre-formed tunnel segment to measure the three-dimensional coordinates of a target point in real time. The rearview prism is set at a predetermined fixed point on the tunnel segment to provide the total station with an azimuth reference and orientation reference. The laser target is integrated and installed inside the front shield of the tunnel boring machine at the vertical center axis position. It is fixed on the rigid mounting surface of the front shield near the rear of the cutterhead to ensure unobstructed line of sight with the total station. It is used to receive the laser beam emitted by the total station. The dual-axis tilt sensor integrated inside can simultaneously collect the pitch and roll angle attitude data of the tunnel boring machine. Several target prisms are installed inside the front shield of the tunnel boring machine to provide observation targets for the total station. The guidance calculation module is used to calculate in real time the attitude deviation parameters of the front shield and the torque fluctuation characteristics of the cutterhead during the tunneling process of the tunnel boring machine; The geological structure determination module is used to determine whether the tunnel boring machine has entered a composite geological structure of upper soft soil layer and lower hard rock layer based on the composite stratum identification index determined by the attitude deviation parameters and the torque fluctuation characteristics, and the comparison result with the preset stratum index. It also determines whether the settlement control effect is qualified based on the uniformity characterization value of the filling density of the grouting behind the tunnel wall in the excavated area, and optimizes the preset stratum index based on the unqualified conditions. The interface determination module, in response to the tunnel boring machine entering a composite geological structure with a soft upper layer and a hard lower layer, is used to determine the interface of the composite geological structure based on the geological radar detection profile, and to determine the soft-hard ratio coefficient of the composite geological structure based on the extension length of the interface. The guidance adjustment module is used to generate a first guidance adjustment strategy based on the soft-hard ratio coefficient to adjust the thrust difference between the upper and lower cylinders of the tunnel boring machine, and to generate a second guidance adjustment strategy to correct the first guidance adjustment strategy based on the fluctuation rate of the tunneling specific energy curve of the tunnel boring machine within a preset sliding window.

[0067] Specifically, the total station is an ATR (Automatic Target Recognition) total station, which can automatically search for and aim at target prisms or laser targets; the specific model is not limited.

[0068] Specifically, there are three target prisms, which are fixedly installed on the upper, lower left and lower right rigid structures inside the front shield of the tunnel boring machine. Together with the laser target, they form a stable spatial triangular observation layout, and all are within the line of sight of the total station, providing the total station with multi-point, high-precision observation targets and ensuring the stability and accuracy of the tunnel boring machine's three-dimensional coordinate measurement.

[0069] Specifically, after the ATR total station completes the spatial reference orientation of the tunnel design axis through the rearview prism, it continuously emits laser beams towards the laser target of the shield machine's front shield and automatically tracks and observes three target prisms on the upper, lower left, and lower right sides of the front shield, measuring the three-dimensional coordinates of the laser target and the prisms in real time. At the same time, the dual-axis tilt sensor built into the laser target synchronously collects the pitch and roll angle attitude data of the shield machine. The industrial computer integrates the coordinate and attitude data to calculate the horizontal and vertical deviations of the shield machine relative to the design axis and the real-time attitude, and guides the shield machine to correct its deviation and tunnel along the design axis based on the deviation results.

[0070] 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 guiding method for shield tunneling measurement in subway engineering, characterized in that, include: The tunnel boring machine (TBM) advances along the design axis according to the guidance results of the guiding device. The attitude deviation parameters of the front shield and the torque fluctuation characteristics of the cutterhead are obtained in real time during the tunneling process. The attitude deviation parameters include the change in horizontal deviation of the cut and the change in vertical deviation of the cut. Based on the attitude deviation parameters and the torque fluctuation characteristics, a composite stratum identification index is determined. Based on the comparison between the composite stratum identification index and the preset stratum index, it is determined whether the tunnel boring machine has entered a composite geological structure consisting of an upper soft soil layer and a lower hard rock layer. In response to the tunnel boring machine entering a composite geological structure with a soft upper layer and a hard lower layer, a geological radar detection profile map within a preset range in front of the tunnel face is obtained. Based on the extension length of the interface of the composite geological structure, the soft-hard ratio coefficient of the composite geological structure is determined. Based on the soft-hard ratio coefficient, a first guiding adjustment strategy is generated to adjust the thrust difference between the upper and lower cylinders of the tunnel boring machine. Based on the first guidance adjustment strategy, a tunneling specific energy curve of the tunnel boring machine is constructed, and a second guidance adjustment strategy for correcting the first guidance adjustment strategy is generated based on the volatility of the tunneling specific energy curve within a preset sliding window. After the tunneling of the preset section is completed, the settlement control effect is determined based on the uniformity of the filling density of the grouting behind the tunnel wall in the already excavated area. The preset stratum index is then optimized based on the unqualified conditions.

2. The guiding method for shield tunneling measurement in subway engineering according to claim 1, characterized in that, The composite strata identification index is a weighted sum of the quantum index of horizontal deviation change of the cut, the quantum index of vertical deviation change of the cut, and the sub-index of torque fluctuation amplitude matching.

3. The guiding method for shield tunneling measurement in subway engineering according to claim 2, characterized in that, The process of determining whether a tunnel boring machine has entered a complex geological structure consisting of an upper soft soil layer and a lower hard rock layer based on the composite stratum identification index includes: The composite stratigraphic identification index is compared with a preset stratigraphic index; Based on the comparison result that the composite stratum identification index is greater than the preset stratum index, it is determined that the tunnel boring machine has entered a composite geological structure.

4. The guiding method for shield tunneling measurement in subway engineering according to claim 3, characterized in that, When a tunnel boring machine enters a composite geological structure that is soft on top and hard on the bottom, the process of determining the interface of the composite geological structure based on the ground-penetrating radar profile includes: The ground-penetrating radar profile is divided into several horizontal strips at equal intervals along the depth direction, and the average reflection amplitude of each horizontal strip is determined. Using the first horizontal strip below the ground surface as a reference, calculate the amplitude difference of the average reflection amplitude of two adjacent horizontal strips from top to bottom; The horizontal stripe whose amplitude difference first exceeds the preset amplitude is identified as the interface of the composite geological structure.

5. The guiding method for shield tunneling measurement in subway engineering according to claim 4, characterized in that, The process of determining the hardness ratio of the composite geological structure based on the extension length of the interface includes: A cross-sectional coordinate system is established with the center of the shield machine cut as the origin. The circular cut cross-section of the shield machine is divided by a horizontal line corresponding to the burial depth of the interface. The area of ​​the lower part of the divided circular cut cross-section is taken as the area of ​​the hard rock layer. The ratio of the area of ​​the hard rock layer to the total area of ​​the circular cut cross-section is determined as the basic hardness-softness ratio coefficient. The extension length of the interface along the tunneling direction is obtained, and the length ratio of the extension length to the preset length is determined as the extension length weighting coefficient. The product of the extension length weighting coefficient and the basic soft-hard ratio coefficient is determined as the soft-hard ratio coefficient.

6. The guiding method for shield tunneling measurement in subway engineering according to claim 5, characterized in that, The process of generating the first guidance adjustment strategy based on the aforementioned soft-hard ratio coefficient includes: The soft-hard ratio coefficients are compared with preset ratio coefficients respectively; Based on the comparison results between the soft and hard ratio coefficients and the preset ratio coefficients, the thrust difference adjustment coefficient of the upper and lower hydraulic cylinders of the tunnel boring machine is determined.

7. The guiding method for shield tunneling measurement in subway engineering according to claim 6, characterized in that, The process of generating a second guidance adjustment strategy to correct the first guidance adjustment strategy based on the volatility of the tunneling specific energy curve within a preset sliding window includes: Based on the tunneling specific energy curve, the percentage of the average value and standard deviation of the tunneling specific energy within a preset sliding window is determined as the volatility of the tunneling specific energy. The volatility is compared with the preset volatility; Based on the comparison between the volatility and the preset volatility, a second guidance adjustment strategy is generated to modify the first guidance adjustment strategy.

8. The guiding method for shield tunneling measurement in subway engineering according to claim 7, characterized in that, The process of determining whether the settlement control effect is satisfactory based on the homogeneity characterization values ​​includes: The uniformity characterization value is compared with a preset characterization value; Based on the comparison result that the uniformity characterization value is greater than the preset characterization value, it is determined that the settlement control effect is unqualified.

9. The guiding method for shield tunneling measurement in subway engineering according to claim 8, characterized in that, Under conditions where settlement control is inadequate, the process of optimizing the preset formation index includes: The difference between the uniformity characterization value and the preset characterization value is used to obtain the characterization difference value; Based on the comparison results between the characterization difference and the preset characterization difference, several index optimization coefficients are set to optimize the preset formation index.

10. A guiding device for tunnel boring machine (TBM) measurement in subway engineering, employing the guiding method for TBM measurement in subway engineering as described in any one of claims 1-9, characterized in that, include: A total station is a measuring bracket mounted on the side wall of a tunnel segment to measure the three-dimensional coordinates of a target point. A rearview prism, which is mounted on the tunnel segment, is used to provide an azimuth reference for the total station. A laser target is installed inside the front shield of the tunnel boring machine to receive the laser beam emitted by the total station; Several target prisms are installed inside the front shield of the tunnel boring machine to provide observation targets for the total station. The guidance calculation module is used to calculate in real time the attitude deviation parameters of the front shield and the torque fluctuation characteristics of the cutterhead during the tunneling process of the tunnel boring machine; The geological structure determination module is used to determine whether the tunnel boring machine has entered a composite geological structure of upper soft soil layer and lower hard rock layer based on the composite stratum identification index determined by the attitude deviation parameters and the torque fluctuation characteristics, and the comparison result with the preset stratum index. It also determines whether the settlement control effect is qualified based on the uniformity characterization value of the filling density of the grouting behind the tunnel wall in the excavated area, and optimizes the preset stratum index based on the unqualified conditions. The interface determination module, in response to the tunnel boring machine entering a composite geological structure with a soft upper layer and a hard lower layer, is used to determine the interface of the composite geological structure based on the geological radar detection profile, and to determine the soft-hard ratio coefficient of the composite geological structure based on the extension length of the interface. The guidance adjustment module is used to generate a first guidance adjustment strategy based on the soft-hard ratio coefficient to adjust the thrust difference between the upper and lower cylinders of the tunnel boring machine, and to generate a second guidance adjustment strategy to correct the first guidance adjustment strategy based on the fluctuation rate of the tunneling specific energy curve of the tunnel boring machine within a preset sliding window.

Images