Method for controlling posture of shield tunneling machine in large-volume rock protrusion stratum

Abstract

The invention provides a method for controlling the posture of a shield tunneling machine in a large-volume rock protrusion stratum, and is suitable for the field of tunnel shield construction. The method comprises the steps of rock form detection, shield tunneling machine propelling state division, hydraulic thrust adjustment, hydraulic system control and propelling process monitoring, large-size rock in a propelling route is detected through a ground penetrating radar device, the distribution condition of the rock in a stratum is obtained, and the propelling process of the shield tunneling machine is monitored according to the balance of force and torque borne by a cutter head. Hydraulic thrust needed by each thrust oil cylinder for keeping the posture of the current shield tunneling machine is obtained, so that it is guaranteed that the propelling route of the shield tunneling machine conforms to the originally-designed tunnel axis; by monitoring the elongation of the propulsion oil cylinder, the propulsion displacement of the cutterhead is monitored in real time, and the accuracy of the route of the shield tunneling machine is further guaranteed; according to the method, the posture of the shield tunneling machine can be controlled in advance before deviation of the tunneling route of the shield tunneling machine, the construction cost increased by correcting the tunneling route of the shield tunneling machine after deviation is avoided, meanwhile, a large number of existing data training prediction models are not needed, and use is more convenient.

Description

Technical Field

[0001] The present invention relates to the field of tunnel shield construction, and in particular to a method for controlling the posture of a shield machine in a large-volume rock protrusion stratum. Background Art

[0002] With my country's growing demand for underground space, the scale of underground engineering construction continues to grow, particularly for underground tunneling projects, which are expected to maintain this growth trend for a long time to come. With the domestic production of shield machines, the cost of using the shield method for underground tunneling has become increasingly affordable. Due to its advantages of short construction periods, high safety, and minimal impact on the surface environment, the shield method has become the mainstream method for underground tunneling. However, shield tunneling is subject to uncertainties such as complex geological conditions and the operating conditions of the shield machine. This often leads to deviations from the original tunnel axis, seriously impacting construction quality. This is particularly true when encountering irregular, large rock formations. The stable rock formations behind these rock formations provide significant rigidity, causing the cutterhead to move significantly under the initial design thrust of the shield machine while remaining virtually stationary in the rock section. This can cause the shield machine to deviate from its original design path.

[0003] The current traditional solution is to control the shield machine's posture through the hydraulic thrust of the propulsion cylinder when the shield machine's excavation route deviates from the original designed tunnel axis by more than a certain limit, and gradually close to the original designed tunnel axis. Although this method can allow the shield machine's excavation route to continue to return to the original designed tunnel axis, the section that has deviated from the original designed tunnel axis cannot be modified. Moreover, since the shield machine's turning radius is very large, even after the excavation route is found to be deviated, it still takes a long distance to close to the original designed tunnel axis, resulting in a longer construction route and increased construction costs.

[0004] With the increasing popularity of neural network algorithms, there are currently existing schemes for predicting shield machine excavation route deviation based on neural network models. However, these schemes require a large amount of existing data for model training. Under certain geological conditions, the existing data is insufficient to train a model that can accurately predict shield machine excavation route deviation, making it difficult to promote and use. Therefore, when using shield construction in strata with large rock protrusions, it is necessary to develop a method that can control the shield machine's posture in advance before the shield machine excavation route deflects, making it easy to promote and use, and can accurately control the shield machine's posture. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of lengthened construction routes and increased construction costs caused by the post-correction scheme of the traditional shield machine excavation route deviation, as well as the problem that it is difficult to promote and use under special geological conditions caused by the prediction of the offset based on the neural network model. A control method for the shield machine posture in large-volume rock protrusion strata is proposed, which can avoid additional construction costs, has a low usage threshold and is easy to promote, and can be widely used in the field of tunnel shield construction.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] S101, rock morphology detection;

[0008] The rock shape detection includes preliminary rock shape detection, rock precise position and shape parameter detection before the shield machine advances the 3n+1 ring. The preliminary rock shape detection includes using low frequency detection depth H l performing preliminary rock morphology detection using a first ground-penetrating radar device, and determining whether the rock is a large-volume rock based on the rock morphology outline depicted by the first ground-penetrating radar device;

[0009] When the detected rock shape is a large volume of rock, each ring of the shield machine needs to detect the precise position and shape parameters of the rock. The rock precise position and shape parameter detection includes the high frequency detection depth of H when the shield machine cutterhead is installed. s The second ground penetrating radar device is used to establish a polar coordinate system outside the shield machine, with the center of the cutterhead as the origin, facing the cutterhead horizontally to the right as zero degrees, and counterclockwise as positive. The edge of the rock projection on the cutterhead surface and the burial depth h perpendicular to the cutterhead surface are obtained based on the second ground penetrating radar device. b , the burial depth h b Real-time updates during the advancement of the shield machine;

[0010] S102, shield machine propulsion status classification;

[0011] The shield machine advancement state is divided into two states: the shield machine advancement is completed in the first state, when the shield machine does not dig into the rock, the burial depth h b >0, using the initial design thrust F of the shield machine o Hydraulic jacking is performed to complete the shield construction; in the second state, when the shield machine excavates the rock, the burial depth h b =0, the shield machine propulsion cylinder provides the adjusted hydraulic thrust for shield construction;

[0012] S103, hydraulic thrust adjustment;

[0013] The hydraulic thrust adjustment includes the shield machine propulsion cylinder being arranged along the circumference of the radius R' and perpendicular to the cutter head surface, and the radius of the propulsion cylinder is Rl , obtain the polar coordinate point (r b,j ,α j ), the number of hobs m in the projection plane and the number of propulsion cylinders n in the projection plane, and obtain the center coordinates (r b ,α);

[0014] Cutting head surface R′-2R l The circumference of the radius is used as the boundary, the position inside the circumference is the middle position of the cutter disc, and the position outside the circumference is the edge position of the cutter disc; when the rock is only at the edge position of the cutter disc, the hydraulic thrust of the propulsion cylinder in the projection surface directly acts on the rock through the cutter disc, and the hydraulic thrust in the projection surface is based on the initial design thrust F o Calculate the force required for a single disc cutter to penetrate the rock.

[0015]

[0016]

[0017] Where, F res - Initial design thrust F o Force distributed to a single thrust cylinder, kN; F o - initial design thrust, kN; N-total number of propulsion cylinders; F g -The force required for a single disc cutter to penetrate the rock, kN; F sh -Hydraulic thrust of the propulsion cylinder in the projection plane, kN; hydraulic thrust of other positions is in accordance with F res value;

[0018] When the rock appears in the middle of the cutterhead, the shield machine advances slowly and evenly. According to the force balance perpendicular to the cutterhead direction, the resultant force of the hydraulic thrust of all propulsion cylinders, the rock reaction force, and the initial design thrust F o The sum of the values ​​is equal and opposite, and the rock reaction force is the reaction force generated by the rock on the m roller cutters.

[0019]

[0020] Where, F i -The hydraulic thrust of the i-th propulsion cylinder, kN; To prevent the cutterhead from tilting, the torque around the cutterhead center should be balanced, that is, the resultant torque generated by the hydraulic thrust of the propulsion cylinder at the cutterhead center should be equal and opposite to the torque generated by the rock reaction force at the cutterhead center.

[0021]

[0022] Where θ i- the angular coordinate of the i-th propulsion cylinder; then the hydraulic thrust of the i-th propulsion cylinder can be obtained according to the following formula,

[0023] F i =F avg +bcos(θ i -α) (5)

[0024]

[0025] and the hydraulic thrust of the i-th propulsion cylinder does not exceed the rated load capacity of the propulsion cylinder and the equipment. When the calculated hydraulic thrust of the propulsion cylinder exceeds the rated load capacity of the propulsion cylinder and the equipment, the maximum allowable hydraulic thrust of the propulsion cylinder shall be used;

[0026] S104, hydraulic system control;

[0027] The hydraulic system control includes the hydraulic thrust F of each propulsion cylinder required to maintain the posture during the shield machine propulsion process according to the above calculation. i , through the hydraulic control system, the output thrust of each propulsion cylinder of the shield machine is adjusted separately;

[0028] S105, advancement process monitoring;

[0029] The propulsion process monitoring includes installing displacement sensors and pressure sensors to monitor the propulsion displacement and force of the propulsion cylinder at each position in real time, and feeding the monitoring data back to the control system. If it is found that the actual displacement of certain positions deviates from the expected displacement by more than a certain threshold, the thrust of the corresponding hydraulic cylinder is adjusted in time.

[0030] As a preferred technical solution of the present invention, in step S101, the method for determining the bulky rock is that the rock shape exceeds the detection range of the first ground penetrating radar device in any direction.

[0031] As a preferred technical solution of the present invention, in step S101, the detection depth H l It is three times the advancement distance of each ring of the shield machine.

[0032] As a preferred technical solution of the present invention, in step S103, the force required for the single roller cutter to penetrate the rock is calculated according to the following formula:

[0033]

[0034] Where K d - rolling coefficient of rock; R r -Compressive strength of rock, kN / cm 2 ; r i -Cutting edge radius of the hob, cm; β i - half-edge angle of the hob; hi - cutting depth per rotation of the hob, cm; R i - radius of the cutter, cm; φ - natural crushing angle of the rock.

[0035] The beneficial effects of the present invention are as follows: during the advancement of the shield machine, the large volume of rock in the advancement route is detected by a ground penetrating radar device to obtain the distribution of the rock in the stratum, and the hydraulic thrust required for each propulsion cylinder to maintain the current shield machine posture is obtained according to the balance of force and torque acting on the cutter head, thereby ensuring that the shield machine advancement route conforms to the original designed tunnel axis; by monitoring the elongation of the propulsion cylinder, the cutter head advancement displacement is monitored in real time to further ensure the accuracy of the shield machine route; this method can control the shield machine posture in advance before the shield machine excavation route deviates, thereby avoiding the increased construction cost of correcting the shield machine excavation route after the deviation, and at the same time does not require a large amount of existing data to train the prediction model, and is more convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flow chart of a method for controlling the posture of a shield machine in a large-volume rock protrusion stratum. DETAILED DESCRIPTION

[0037] The following describes in detail specific embodiments of the present invention in conjunction with the accompanying drawings. It should be understood that the specific embodiments provided herein are intended only to illustrate and explain the present invention and are not intended to limit the present invention. It should be noted that many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention may also have other embodiments and variations thereof. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0038] Example 1 is based on the drainage tunnel construction project for Units 3 and 4 of the Zhangzhou Nuclear Power Plant. The shield tunnel uses a assembled single-layer lining. The segments have an outer diameter of 7.3m, an inner diameter of 6.5m, a thickness of 0.4m, and a ring width of 1.6m. The shield machine excavates in rings, advancing each ring by 1.6m. Each ring takes approximately 90 minutes to advance. The method for controlling the shield machine's posture in large rock protrusions is as follows:

[0039] Before the shield machine advances the 3n+1 ring, preliminary rock shape detection, rock precise position and shape parameter detection are carried out. The preliminary rock shape detection includes using low-frequency detection with a depth of H lThe first ground-penetrating radar device is used to conduct preliminary rock morphology detection. When the detected rock morphology is large-volume rock, it indicates that the rock has a stable rock layer. When the rock contacts the cutterhead, the stable rock layer behind the rock can provide great rigidity, causing the cutterhead to have a large displacement when cutting the soil part under the initial design thrust of the shield machine, while the part cutting the rock is almost motionless, thus causing the shield machine posture to deviate from the original design route. The method for determining large-volume rock is that the rock morphology exceeds the detection range of the first ground-penetrating radar device in any direction. The detection depth H l It is three times the advancing distance of each ring of the shield machine;

[0040] When the detected rock shape is a large volume of rock, each ring of the shield machine needs to detect the precise position and shape parameters of the rock. The rock precise position and shape parameter detection includes the high frequency detection depth of H when the shield machine cutterhead is installed. s The second ground penetrating radar device is used to establish a polar coordinate system outside the shield machine, with the center of the cutterhead as the origin, facing the cutterhead horizontally to the right as zero degrees, and counterclockwise as positive. The edge of the rock projection on the cutterhead surface and the burial depth h perpendicular to the cutterhead surface are obtained based on the second ground penetrating radar device. b , the burial depth h b Real-time updates during the advancement of the shield machine;

[0041] The shield machine is advanced in two states. In the first state, when the shield machine does not dig into the rock, the burial depth h b >0, the initial design thrust of the shield machine is used for hydraulic jacking to complete the shield construction; in the second state, when the shield machine excavates the rock, the burial depth h b =0, the shield machine propulsion cylinder provides the adjusted hydraulic thrust for shield construction;

[0042] The thrust cylinder of the shield machine is arranged along a circle with a radius of R′=3200mm and perpendicular to the cutterhead surface. The radius of the thrust cylinder is R l =200mm, the cutter head radius R = 3600mm is slightly larger than R' and R l The hydraulic thrust adjustment includes obtaining the polar coordinate point (r b，j ,α j ), the number of hobs m in the projection plane and the number of propulsion cylinders n in the projection plane, and according to the polar coordinate points (r b，j ,α j ) to obtain the center coordinates (r b ,α), there are two distribution forms of rocks on the cutterhead surface. One is that rocks appear in the middle of the cutterhead, and the other is that rocks appear at the edge of the cutterhead. l=2800mm as the radius of the circle as the boundary, the position inside the circle is the middle position of the cutter disc, and the position outside the circle is the edge position of the cutter disc; when the rock is only at the edge position of the cutter disc, the hydraulic thrust of the propulsion cylinder in the projection surface directly acts on the rock through the cutter disc, and the hydraulic thrust in the projection surface is based on the initial design thrust F o Calculate the force required for a single disc cutter to penetrate the rock.

[0043]

[0044] Where, F res - Initial design thrust F o Force distributed to a single thrust cylinder, kN; F o - initial design thrust, kN; N-total number of propulsion cylinders; F g -The force required for a single disc cutter to penetrate the rock, kN; K d - Rock rolling coefficient, take 0.55; R r - Rock compressive strength, in this example, 75 MPa = 7.5 kN / cm 2 ; r i - The blade radius of the hob, in this embodiment, the blade radius of the hob at each position is uniformly 8 cm; θ i - half blade angle of the hob, which is 30° in this embodiment; h i - The cutting depth per rotation of the hob is 1 cm in this embodiment; R i - radius of the cutter, which is 21.6 cm in this embodiment; φ - natural crushing angle of the rock, which is 155° in this embodiment; F sh - Projected hydraulic thrust, kN; initial design thrust F o Including the friction between the shield machine and the soil, the earth pressure on the cutter head, the thrust required for cutting the soil, the friction between the shield tail and the pipe segment, and the drag force of the rear trolley; the hydraulic thrust at other positions is calculated according to F res The value is selected to ensure that the cutterhead can move forward normally after the rock is crushed by the cutterhead. When the rock appears in the middle position relative to the cutterhead, since the shield machine advances slowly and uniformly, according to the force balance perpendicular to the cutterhead direction, the resultant force of the hydraulic thrust of all propulsion cylinders is equal to and opposite to the sum of the rock reaction force and the initial design thrust Fo. The rock reaction force is the reaction force generated by the rock on the m roller cutters.

[0045]

[0046] Where, F i -The hydraulic thrust of the i-th propulsion cylinder, kN; To prevent the cutterhead from tilting, the torque around the cutterhead center should be balanced, that is, the resultant torque generated by the hydraulic thrust of the propulsion cylinder at the cutterhead center should be equal and opposite to the torque generated by the rock reaction force at the cutterhead center.

[0047]

[0048] Where θ i - the angular coordinate of the i-th propulsion cylinder; then the hydraulic thrust of the i-th propulsion cylinder can be obtained according to the following formula,

[0049] F i =F avg +bcos(θ i -α) (6)

[0050]

[0051] and the hydraulic thrust of the i-th propulsion cylinder does not exceed the rated load capacity of the propulsion cylinder and the equipment. When the calculated hydraulic thrust of the propulsion cylinder exceeds the rated load capacity of the propulsion cylinder and the equipment, the maximum allowable hydraulic thrust of the propulsion cylinder shall be used;

[0052] According to the hydraulic thrust F of each propulsion cylinder required to maintain the posture during the shield machine's advancement i , through the hydraulic control system, the output thrust of each propulsion cylinder of the shield machine is adjusted separately;

[0053] Install a displacement sensor and a pressure sensor, and use the displacement sensor to monitor the elongation of the propulsion cylinder at each position in real time, so as to obtain the propulsion displacement of the cutter disc, and feed the monitoring data back to the control system. If the actual displacement of some positions exceeds the expected displacement by 10%, the output thrust of the corresponding propulsion cylinder is reduced by 10%; if the actual displacement of some positions is lower than the expected displacement by 10%, the output thrust of the corresponding propulsion cylinder is increased by 10%. If the increased output thrust exceeds the maximum allowable hydraulic thrust of the propulsion cylinder, the output thrust of the propulsion cylinder is not increased, but the output thrust of the remaining propulsion cylinders is reduced by 10% synchronously; the expected displacement is determined according to the propulsion distance of each ring and the time required to advance one ring. In this embodiment, the expected displacement per minute during the propulsion of each ring is 17.78 mm.

[0054] Table 1 Expected displacement table

[0055] Time t (min) 1 2 3 … 88 89 90 Expected displacement (mm) 17.78 35.55 53.33 … 1564.44 1582.22 1600

[0056] In summary, the method for controlling the posture of a shield machine in a large-volume rock protrusion stratum of the present invention can control the posture of the shield machine in the field of tunnel shield construction to ensure that the tunnel axis does not deviate.

[0057] It should be understood that the above embodiments are one or more embodiments of the present invention, and there are many other embodiments and variations thereof based on the present invention; the variations and modifications made by ordinary technicians in this industry through the present invention without making groundbreaking innovations all fall within the scope of protection of the present invention.

Claims

1. A method for controlling the posture of a shield machine in a large rock protrusion stratum, characterized in that The specific steps include: S101, rock morphology detection; The rock shape detection includes preliminary rock shape detection, rock precise position and shape parameter detection before the shield machine advances the 3n+1 ring. The preliminary rock shape detection includes using low frequency detection depth H l performing preliminary rock morphology detection using a first ground-penetrating radar device, and determining whether the rock is a large-volume rock based on the rock morphology outline depicted by the first ground-penetrating radar device; When the detected rock shape is a large volume of rock, each ring of the shield machine needs to detect the precise position and shape parameters of the rock. The rock precise position and shape parameter detection includes the high frequency detection depth of H when the shield machine cutterhead is installed. s The second ground penetrating radar device is used to establish a polar coordinate system outside the shield machine, with the center of the cutterhead as the origin, facing the cutterhead horizontally to the right as zero degrees, and counterclockwise as positive. The edge of the rock projection on the cutterhead surface and the burial depth h perpendicular to the cutterhead surface are obtained based on the second ground penetrating radar device. b , the burial depth h b Real-time updates during the advancement of the shield machine; S102, shield machine propulsion state classification; The shield machine advancement state is divided into two states: the shield machine advancement is completed in the first state, when the shield machine does not dig into the rock, the burial depth h b >0, using the initial design thrust F of the shield machine o Hydraulic jacking is performed to complete the shield construction; in the second state, when the shield machine excavates the rock, the burial depth h b =0, the shield machine propulsion cylinder provides the adjusted hydraulic thrust for shield construction; S103, hydraulic thrust adjustment; The hydraulic thrust adjustment includes the shield machine propulsion cylinder being arranged along the circumference of the radius R' and perpendicular to the cutter head surface, and the radius of the propulsion cylinder is R l , obtain the polar coordinate point (r b,j ,α j ), the number of hobs m in the projection plane and the number of propulsion cylinders n in the projection plane, and obtain the center coordinates (r b ,α); Cutting head surface R′-2R l The circumference of the radius is used as the boundary, the position inside the circumference is the middle position of the cutter disc, and the position outside the circumference is the edge position of the cutter disc; when the rock is only at the edge position of the cutter disc, the hydraulic thrust of the propulsion cylinder in the projection surface directly acts on the rock through the cutter disc, and the hydraulic thrust in the projection surface is based on the initial design thrust F o Calculate the force required for a single disc cutter to penetrate the rock. Where, F res - Initial design thrust F o Force distributed to a single thrust cylinder, kN; F o - initial design thrust, kN; N-total number of propulsion cylinders; F g -The force required for a single disc cutter to penetrate the rock, kN; F sh -Hydraulic thrust of the propulsion cylinder in the projection plane, kN; hydraulic thrust of other positions is in accordance with F res value; When the rock appears in the middle of the cutterhead, the shield machine advances slowly and evenly. According to the force balance perpendicular to the cutterhead direction, the resultant force of the hydraulic thrust of all propulsion cylinders, the rock reaction force, and the initial design thrust F o The sum of the values ​​is equal and opposite, and the rock reaction force is the reaction force generated by the rock on the m roller cutters. Where, F i -The hydraulic thrust of the i-th propulsion cylinder, kN; To prevent the cutterhead from tilting, the torque around the cutterhead center should be balanced, that is, the resultant torque generated by the hydraulic thrust of the propulsion cylinder at the cutterhead center should be equal and opposite to the torque generated by the rock reaction force at the cutterhead center. Where θ i - the angular coordinate of the i-th propulsion cylinder; then the hydraulic thrust of the i-th propulsion cylinder can be obtained according to the following formula, F i =F avg +bcos(θ i -a) (5) and the hydraulic thrust of the i-th propulsion cylinder does not exceed the rated load capacity of the propulsion cylinder and the equipment. When the calculated hydraulic thrust of the propulsion cylinder exceeds the rated load capacity of the propulsion cylinder and the equipment, the maximum allowable hydraulic thrust of the propulsion cylinder shall be used; S104, hydraulic system control; The hydraulic system control includes the hydraulic thrust F of each propulsion cylinder required to maintain the posture during the shield machine propulsion process according to the above calculation. i , through the hydraulic control system, the output thrust of each propulsion cylinder of the shield machine is adjusted separately; S105, advancement process monitoring; The propulsion process monitoring includes installing displacement sensors and pressure sensors to monitor the propulsion displacement and force of the propulsion cylinder at each position in real time, and feeding the monitoring data back to the control system. If it is found that the actual displacement of certain positions deviates from the expected displacement by more than a certain threshold, the thrust of the corresponding hydraulic cylinder is adjusted in time.

2. The method for controlling the posture of a shield machine in a large rock protrusion stratum according to claim 1, characterized in that: In step S101, the large rock is determined as being beyond the detection range of the first ground penetrating radar device in any direction.

3. The method for controlling the posture of a shield machine in a large rock protrusion stratum according to claim 1, characterized in that: In step S101, the detection depth H l It is three times the advancement distance of each ring of the shield machine.

4. The method for controlling the posture of a shield machine in a large rock protrusion stratum according to claim 1, characterized in that: In step S103, the force required for the single cutter to penetrate the rock is calculated according to the following formula: Where K d - rolling coefficient of rock; R r -Compressive strength of rock, kN / cm 2 ; r i -Cutting edge radius of the hob, cm; β i - half-edge angle of the hob; h i - cutting depth per rotation of the hob, cm; R i - radius of the cutter, cm; φ - natural crushing angle of the rock.

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