A method, system and storage medium for segment bearing safety early warning under the synchronous pushing and assembling mode of a large-diameter shield tunneling machine

Abstract

The present invention discloses a method, system and storage medium for safety warning of segment bearing under the synchronous pushing and assembling mode of a large-diameter shield. The method comprises the following steps: S1, constructing a construction three-dimensional grid model; S2, analyzing and obtaining the soil and water stress and the shield tail rebound force received by the segment; S3, performing finite element simulation according to the construction three-dimensional grid model, the soil and water stress and the shield tail rebound force to obtain the ultimate deformation of the segment; S4, determining whether the ultimate deformation of the segment is greater than the safety threshold: if so, outputting a warning message. The present invention utilizes finite element simulation technology. This method can obtain the ultimate deformation data of the segment under the synchronous pushing and assembling mode, and compare it with the safety threshold. When the ultimate deformation exceeds the safety threshold, the system will automatically output a warning message, providing timely feedback to the construction personnel so as to take corresponding preventive measures.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnel segment construction, and in particular, to a method, system, and storage medium for early warning of segment bearing safety in the synchronous pushing and assembling mode of large-diameter shields. Background Art

[0002] Conventional shield construction adopts an alternating pushing and assembling mode, which makes different systems of the shield machine have to start and stop frequently, seriously affecting the efficiency of tunnel construction. Synchronous pushing and assembling is a very promising method to solve this problem. Synchronous pushing and assembling means that while the shield machine is advancing forward, a part of the cylinders are retracted to complete the assembly of the segments, so that shield propulsion and segment assembly can be achieved simultaneously. Since the distance between the cylinders is smaller in the synchronous pushing and assembling mode than in the conventional mode, the relative positions of the shield tail structure and the segments are quite different from those in the conventional assembly, which makes the stress situation of the segments uncertain, resulting in insufficient supporting force of the segments and deformation or even damage. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. For this purpose, the present invention provides a method for early warning of segment bearing safety in the synchronous pushing and assembling mode of large-diameter shields.

[0004] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A method for early warning of segment bearing safety in the synchronous pushing and assembling mode of large-diameter shields includes the following steps: S1, constructing a three-dimensional construction grid model; S2, analyzing and obtaining the soil and water stress and shield tail rebound force received by the segments; S3, performing finite element simulation based on the three-dimensional construction grid model, soil and water stress, and shield tail rebound force to obtain the ultimate deformation of the segments; S5, determining whether the ultimate deformation of the segments is greater than the safety threshold: if so, outputting a warning message.

[0006] Further, step S2 includes:

[0007] Obtaining the stress of the soil layer in the vertical direction:

[0008] ;

[0009] is the unit weight of the soil at depth of the soil, is the Poisson's ratio of the soil, h is the depth of the soil layer, is the stress of the soil layer in the vertical direction, is the coefficient of lateral pressure;

[0010] Obtaining the soil and water stress received by the segments in polar coordinates as:

[0011] ;

[0012] is the tunnel radius, is the radial normal stress, is the circumferential normal stress, is the radial shear stress, is the tangential shear stress; R is the distance from the soil layer to the center point of the tunnel, is the polar coordinate angle of the position where the soil layer is located.

[0013] Furthermore, step S2 further includes: according to the grease pressure received by the segment being , for , , perform correction to obtain the corrected soil stress received by the segment:

[0014] .

[0015] Furthermore, step S2 includes:

[0016] Obtain the vertical component of the shield tail rebound force of the segment :

[0017] = ;

[0018] where represents the -th interval when the interval with an angle of is divided into parts, is the rebound force provided by the shield tail brush per unit arc length; is the starting angle of the shield tail brush arrangement, is the coverage angle of the shield tail brush arrangement range.

[0019] Furthermore, step S3 includes: through time stepping, simulate the change of the segment's force and the ultimate deformation during the synchronous pushing and assembling process.

[0020] Furthermore, the said through time stepping, simulate the change of the segment's force and the ultimate deformation during the synchronous pushing and assembling process, specifically includes:

[0021] At the first time step, the cylinder thrust is applied on the entire segment shoe surface to simulate the force when a ring of segments is installed, and obtain the ultimate deformation of the segment;

[0022] At the second time step, remove the thrust of three adjacent cylinders to simulate the force condition when installing the next ring of segments, and obtain the ultimate deformation of the segment.

[0023] Further, step S1 specifically includes: constructing a construction three-dimensional grid model based on the basic three-dimensional model, the cylinder distance, the segment splicing characteristics, and the shield tail brush support condition.

[0024] Further, the cylinder distance d satisfies: .

[0025] The present invention also proposes a tunnel segment bearing safety warning system applicable to the synchronous pushing and splicing mode of a shield tunneling machine, including: a three-dimensional model construction module for constructing a construction three-dimensional grid model; a force analysis module for analyzing and obtaining the soil and water stress and the shield tail rebound force acting on the segments; a finite element simulation module for performing finite element simulation based on the construction three-dimensional grid model, the soil and water stress, and the shield tail rebound force to obtain the ultimate deformation of the segments; and a judgment module for judging whether the ultimate deformation of the segments is greater than the safety threshold. If the ultimate deformation is greater than the safety threshold, a warning message is output.

[0026] The present invention also proposes a storage medium in which a computer program is stored. When the computer program is executed by a processor, the steps of the method are implemented.

[0027] The present invention has the following beneficial effects:

[0028] By constructing a construction three-dimensional grid model and combining the analysis of the soil and water stress and the shield tail rebound force, it is possible to accurately simulate the stress condition of the segments during the synchronous pushing and splicing process of the shield tunneling machine, timely discover possible problems of insufficient support force of the segments, prevent segment deformation or damage, and thus ensure construction safety; using the finite element simulation technology, this method can obtain the ultimate deformation data of the segments in the synchronous pushing and splicing mode and compare it with the safety threshold. When the ultimate deformation exceeds the safety threshold, the system will automatically output a warning message to provide timely feedback to the construction personnel so that corresponding preventive measures can be taken.

[0029] In addition to the purposes, features, and advantages described above, the present invention has other purposes, features, and advantages. The present invention will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0031] Figure 1 is the overall flow schematic diagram of the present invention;

[0032] Figure 2 is the cross-sectional view of the synchronous pushing and splicing construction model provided by the present invention;

[0033] Figure 3Schematic diagram of the shield tail structure when the cylinder distance provided by the present invention is 2400 mm;

[0034] Figure 4 Schematic diagram of the shield tail structure when the cylinder distance provided by the present invention is 2800 mm;

[0035] Figure 5 Schematic diagram of the shield tail structure when the cylinder distance provided by the present invention is 3200 mm;

[0036] Figure 6 Relationship between the vertical support component of the shield tail rebound force and the arrangement angle of the shield tail brush;

[0037] Figure 7 Schematic diagram of providing an upward vertical component force for the shield tail brush;

[0038] Figure 8 Analysis diagram of the segment under the cylinder thrust at the first time step provided by the present invention;

[0039] Figure 9 Analysis diagram of the segment under the cylinder thrust at the second time step provided by the present invention;

[0040] Figure 10 Deformation nephogram of the segment provided by the present invention.

[0041] Legend description:

[0042] Shield body 1, segment 2, segment support shoe surface 3, shield tail support structure 4. Detailed implementation manners

[0043] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0045] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0046] In addition, the descriptions involving "first", "second", etc. in the present invention are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0047] Please refer to Figure 1 , a segment bearing safety warning method under the synchronous pushing and assembling mode of a large-diameter shield provided by an embodiment of the present invention includes steps S1, S2, S3, and S4.

[0048] S1, construct a construction three-dimensional grid model; specifically, step S1 specifically includes: constructing a construction three-dimensional grid model according to the basic three-dimensional model, the cylinder distance, the segment splicing characteristics, and the shield tail brush support conditions. Refer to Figure 2 , the main structures during the construction process include the shield body 1, the segments 2, and the shield tail support structure 4. The shield tail support structure 4 includes shield tail brushes. The segments 2 are divided into multiple sections and have several segment support shoe surfaces for the cylinders to contact and push. The cylinders are located at the front end of the shield machine and are used to support the side of the segments when assembling the segments. Relying on the frictional force, the segments are temporarily fixed, and then the segments can be installed. The cylinder distance represents the distance from the segments to the front end of the shield machine, and this distance affects the relative position of the segments and the effect of synchronous pushing and assembling. The segment splicing characteristics are: simplified to four-ring segments, where the last two-ring segments are simplified into an integral body, as Figure 2 shown, and the first two-ring segments are spliced with staggered joints.

[0049] S2, analyze and obtain the soil and water stress and the shield tail rebound force acting on the segments.

[0050] S3, perform finite element simulation based on the construction three-dimensional grid model, the soil and water stress, and the shield tail rebound force to obtain the ultimate deformation of the segments. It can be understood that a finite element model is constructed according to the construction three-dimensional grid model, the soil and water stress, the shield tail rebound force, the material properties, and the contact conditions, and then finite element simulation is carried out using the finite element model to obtain the stress condition and the ultimate deformation of the segments.

[0051] S4, determine whether the ultimate deformation of the segments is greater than the safety threshold: if so, output a warning message to prompt the construction personnel to optimize the segment support. If not, it means that the support condition of the segments is within the safe range.

[0052] A method for warning of segment bearing safety in the synchronous pushing and assembling mode of a large-diameter shield tunneling machine provided by an embodiment of the present invention can accurately simulate the stress condition of segments during the synchronous pushing and assembling process of the shield tunneling machine by constructing a three-dimensional construction grid model and combining the analysis of water and soil stress and tail shield rebounding force, timely detect possible insufficient support force of segments, prevent segment deformation or damage, and thus ensure construction safety; by using finite element simulation technology, this method can obtain the ultimate deformation data of segments in the synchronous pushing and assembling mode and compare it with a safety threshold. When the ultimate deformation exceeds the safety threshold, the system will automatically output a warning message to provide timely feedback to construction personnel so as to take corresponding preventive measures; by accurately evaluating the bearing capacity of segments, this method helps to optimize the design and construction plan of the shield tunneling machine. Especially when there is a large difference between the relative positions of the tail shield structure and segments and the conventional assembly, it can provide more accurate technical guidance for construction.

[0053] In some embodiments of the present invention, step S2 includes:

[0054] Obtain the stress of the soil layer in the vertical direction:

[0055] ;

[0056] is the unit weight of the soil mass at depth , is the Poisson's ratio of the soil mass, h is the depth of the soil layer, is the stress of the soil layer in the vertical direction, is the coefficient of lateral pressure;

[0057] Obtain the water and soil stress acting on the segment in polar coordinates as:

[0058] ;

[0059] is the tunnel radius, is the radial normal stress, is the circumferential normal stress, is the radial shear stress, is the tangential shear stress, and act perpendicular to each other, and are forces with different directions but equal magnitudes. R is the distance from the soil layer to the center point of the tunnel, is the polar coordinate angle of the position where the soil layer is located. R in polar coordinates is the radial distance, is the angle between the line connecting the position where the soil layer is located and the center of the circle and the x-axis. These two parameters can determine a polar coordinate position, and the polar coordinate position represents a distance of R from the center point of the tunnel and a direction angle of The soil micro-elements. In this way, the stress condition of the soil mass is obtained.

[0060] Step S2 further includes: According to the grease pressure received by the segment , for , , perform correction.

[0061] Specifically, the water and soil stress caused by the grease pressure is , , :

[0062] .

[0063] For , , perform correction to obtain the corrected water and soil stress received by the segment , , :

[0064] .

[0065] From the above, the corrected water and soil stress received by the segment can be obtained:

[0066] .

[0067] By considering the grease pressure, a more realistic soil stress is simulated, so as to obtain more accurate soil stress and the force condition of the segment, providing more accurate basic data for subsequent calculations and warnings.

[0068] In some embodiments of the present invention, step S2 includes:

[0069] Obtain the component force of the shield tail rebound force of the segment in the vertical direction :

[0070] = ;

[0071] Refer to Figure 6 and Figure 7 , where represents the th interval when the interval with an angle of is divided into parts, is the total number of sub-intervals when the interval with an angle of is divided, is the number of the sub-interval, is the coverage angle of the shield tail brush arrangement range. is the rebound force provided by the shield tail brush per unit arc length; It is the starting angle for the arrangement of the tail seal brush. Thus, the vertical component of the tail seal rebound force, that is, the force that plays a supporting role, is obtained, providing an accurate data basis for simulating the stress of real segments.

[0072] In some embodiments of the present invention, in step S3, the finite element simulation includes: by time-stepping, simulating the stress changes and ultimate deformations of the segments during the synchronous pushing and assembling process, that is, simulating the stress and deformation in various states during the construction process, so that the entire construction process can be simulated and predicted, and full-process safety analysis and early warning can be achieved.

[0073] In a further embodiment of the present invention, the simulating the stress changes and ultimate deformations of the segments during the synchronous pushing and assembling process by time-stepping specifically includes:

[0074] Referring to Figure 8 , at the first time step, the oil cylinder thrust is applied to all the segment shoe surfaces 3 to simulate the stress when a ring of segments is installed, and the ultimate deformation of the segments is obtained.

[0075] Referring to Figure 9 , when installing the lowermost segment, three oil cylinder thrusts need to be withdrawn first. Therefore, at the second time step, the thrusts of three adjacent oil cylinders are removed to simulate the stress condition when installing the next ring of segments, and the ultimate deformation of the segments is obtained.

[0076] Referring to Figures 3 to 5 , in a specific embodiment of the present invention, the oil cylinder distance d satisfies: , and the oil cylinder distance within this range is within the controllable and safe selection range. Referring to Figure 10 , usually, finite element simulations need to be carried out for different lengths of oil cylinder distances to verify their safety. In this example, since the stress on the lowermost two segments is the greatest, the deformation nephogram of the lowermost two segments is taken as the result output, see Figure 10 .

[0077] The present invention also proposes a tunnel segment bearing safety early warning system applicable to the shield synchronous pushing and assembling mode, including: a three-dimensional model construction module for constructing a construction three-dimensional grid model; a force analysis module for analyzing and obtaining the soil and water stress and the tail seal rebound force received by the segments; a finite element simulation module for performing finite element simulation according to the construction three-dimensional grid model, the soil and water stress, and the tail seal rebound force to obtain the ultimate deformation of the segments; a judgment module for judging whether the ultimate deformation of the segments is greater than the safety threshold, and if the ultimate deformation is greater than the safety threshold, outputting an early warning message.

[0078] The present invention also proposes a storage medium, in which a computer program is stored, and when the computer program is executed by a processor, the steps of the method are implemented.

[0079] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for early warning of segment load safety in a large-diameter shield synchronous push-to-assemble mode, characterized in that: The steps include: S1, constructing a three-dimensional grid model for construction; S2, analyze and obtain the water and soil stress and shield tail rebound force on the segment; S3, finite element simulation is performed based on the construction three-dimensional grid model, water and soil stress and shield tail rebound force to obtain the ultimate deformation of the segment; S4, determine whether the ultimate deformation of the segment is greater than the safety threshold: If so, output warning information; Step S2 includes: Get the stress of the soil layer in the vertical direction: ； The soil at depth The unit weight, is the Poisson's ratio of the soil, h is the depth of the soil layer, is the vertical stress of the soil layer, is the lateral pressure coefficient; The water and soil stress on the segment in polar coordinates is obtained as: ； is the tunnel radius, is the radial normal stress, is the hoop normal stress, is the radial shear stress, is the tangent shear stress; R is the distance from the soil layer to the center of the tunnel, is the polar coordinate angle of the soil layer; Step S2 includes: Obtain the vertical component of the shield tail rebound force of the segment : = ； in Indicates that the angle is The interval is divided into The first intervals, It is the rebound force provided by the shield tail brush per unit arc length; is the starting angle of the shield tail brush arrangement, The coverage angle of the shield tail brush arrangement range.

2. The segment bearing safety early warning method in the synchronous pushing and assembling mode of a large-diameter shield according to claim 1 is characterized in that: Step S2 also includes: according to the grease pressure on the pipe segment ,right , , Make corrections to obtain the corrected water and soil stresses on the segment: 。 3. The segment load safety early warning method in the synchronous pushing and assembling mode of a large-diameter shield according to claim 1 is characterized in that: Step S3 includes: Through time stepping, the changes in stress and ultimate deformation of the segments during the synchronous pushing and assembly process are simulated.

4. The segment bearing safety early warning method in the synchronous pushing and assembling mode of a large-diameter shield according to claim 3 is characterized in that: The simulation of the change of the force and the ultimate deformation of the pipe segments during the synchronous pushing and assembling process by time stepping specifically includes: In the first time step, the cylinder thrust is applied to all the segment support shoe surfaces to simulate the force when a ring of segments is installed and obtain the ultimate deformation of the segment; In the second time step, the thrust of the three adjacent cylinders is removed to simulate the stress conditions when installing the next ring of segments and obtain the ultimate deformation of the segments.

5. The segment load safety early warning method in the synchronous pushing and assembling mode of a large-diameter shield according to claim 1 is characterized in that: Step S1 specifically includes: constructing a construction three-dimensional grid model according to the basic three-dimensional model, the oil cylinder distance, the segment splicing characteristics and the shield tail brush support situation.

6. The segment load safety early warning method in the synchronous pushing and assembling mode of a large-diameter shield according to claim 5 is characterized in that: The cylinder distance d satisfies: .

7. A tunnel segment load safety warning system suitable for use in a shield synchronous push-to-assemble mode, used to implement the segment load safety warning method in a large-diameter shield synchronous push-to-assemble mode as claimed in any one of claims 1 to 6, characterized in that: include: 3D model building module, used to build a 3D grid model for construction; Force analysis module, used to analyze and obtain the water and soil stress on the segment and the rebound force of the shield tail; Finite element simulation module, used to perform finite element simulation based on the construction 3D grid model, water and soil stress and shield tail rebound force to obtain the ultimate deformation of the segment; The judgment module is used to judge whether the ultimate deformation of the pipe segment is greater than the safety threshold. If the ultimate deformation is greater than the safety threshold, an early warning message is output.

8. A storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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