Five-dimensional spatial effect test and monitoring system of ground settlement caused by dual-mode shield construction

Abstract

The invention discloses a five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction, comprising a test model box, a test monitoring system and a shield machine model device, wherein the model test box is used to simulate actual construction geological conditions; the shield machine model comprises a nested inner shield body and an outer shield body, the front part of the outer shield body is a local hollow area, a bracket-like component is arranged between the inner shield body and the outer shield body, one end of a thrust rod is fixed on the bracket-like component, and the other end is connected to a jacking device, and the jacking device is simultaneously connected to a slag dust collector; a cutter head with a tool is arranged at the front part of the shield machine model, the cutter head is connected to a rotating motor through a torque rod, the torque rod is driven by the rotation of the rotating motor, thereby driving the cutter head to rotate and cut soil, so as to provide technical support for revealing and analyzing the spatial and temporal characteristics of surface settlement caused by shield tunnel construction, and determining the evolution law of surface settlement under the influence of shield step length and time effect.

Description

Technical Field

[0001] The invention belongs to the technical field of shield models, and in particular relates to a system and method for testing the "five-dimensional" spatial effect of surface settlement caused by shield construction. Background Art

[0002] Shield machine equipment is mainly divided into full-section hard rock tunnel boring machines (TBMs) for excavating hard rock intervals, earth pressure balance shield machines (EPBs) for excavating soft rock intervals, and dual-mode shield construction under complex geological conditions. However, whether it is TBM method, EPB method or dual-mode shield method construction, there are common characteristics in their construction process, that is, there is a shield machine advancement process and a pipe segment installation process. Analysis of these two specific working conditions shows that the advancement process of the shield machine will disturb the stratum soil. For example, a certain rail transit line uses a shield advancement step length of 1.5m, which inevitably causes surface settlement. During the pipe segment installation stage after each step of advancement, the machine is generally shut down for about 40 minutes, and surface settlement continues to occur during this period.

[0003] Summarizing the above specific engineering situations, as the shield tunnel continues to advance, the ground surface will settle. The ground settlement is not only distributed in the three dimensions of X, Y, and Z, but also evolves continuously with the length (L) and time (T) of the shield tunnel. Therefore, it is defined as the "five-dimensional" spatial effect of ground settlement caused by shield tunnel construction.

[0004] Currently, finite element software or Peck's formula is mostly used to predict the total amount of surface subsidence. Finite element calculation requires the establishment of an accurate model, but the physical properties of each layer of rock in the real stratigraphic environment are ever-changing, so modeling will be very difficult. Peck's formula is a simple method for calculating surface subsidence, which contains many assumptions, so the calculation results will have large errors.

[0005] Traditional model test systems or methods require simplification of the prototype and are limited in terms of similar formation materials, boundary conditions, size effects of test equipment, consolidation and drainage, so they can generally only conduct qualitative research. It is difficult to accurately reflect the "five-dimensional" effects that cause surface subsidence, and it has great limitations on studying the evolution laws of surface subsidence troughs. There are also great difficulties in converting test results into prototypes and directly using them for construction control. Summary of the invention

[0006] In view of the defects of the prior art, the present invention proposes a five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction. By designing a shield machine model, the surface settlement of the prototype shield machine construction is simulated to the greatest extent. By intuitively observing the settlement law and based on the observed data, guidance is provided for the shield machine construction of actual projects, the protection of ground buildings and underground pipelines, etc.

[0007] The present invention is implemented by adopting the following technical scheme: a five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction, comprising a test model box, a test monitoring system and a shield machine model device, wherein the test model box is used to simulate actual construction geological conditions;

[0008] The shield machine model adopts a double shield mode, including a nested inner shield and outer shield, a thrust rod, a jacking device and a slag dust collector. The front part of the outer shield is a partial hollow area. A bracket-like component is arranged between the inner shield and the outer shield. One end of the thrust rod is fixed on the bracket-like component, and the other end is connected to the jacking device. The jacking device is also connected to the slag dust collector, and the slag dust collector is placed on an electronic scale. Not only can the stratum loss generated during the advancement of the model shield machine be accurately known, but also the stratum loss can be accurately controlled during the advancement of the model shield machine, so as to better simulate the movement law of the ground surface under different stratum loss conditions.

[0009] A cutterhead with a tool is provided at the front of the shield machine model. The cutterhead is connected to a rotating motor through a torque rod. The rotating motor is connected to an AC power supply. The torque rod is driven by the rotation of the rotating motor, thereby driving the cutterhead to rotate and cut the soil.

[0010] Furthermore, the test model box includes a box with an upper opening, in which similar strata are simulated, tempered glass plates are used on the sides of the box, and steel plates are used on the bottom of the box. Adjacent tempered glass plates are connected by double-leg angle steels, and sealant is used to improve the sealing.

[0011] Furthermore, the test monitoring system uses a three-dimensional laser scanner to monitor surface settlement, and simulates the continuous advancement process of the shield through a model shield machine to monitor the step dimension. A timer is used to cooperate with the shield machine shutdown condition and the fully advanced completion condition. Through these two conditions, the time dimension is monitored to achieve the five-dimensional monitoring mentioned in this patent. Multiple surface monitoring points are arranged on the surface of the simulated stratum of the test model box, and surface monitoring probes are set on the surface monitoring points. The surface monitoring points are arranged both vertically and horizontally. The starting point and the end point are far away from the boundary of the model box and are not affected by the boundary conditions. The displacement of the tip of the surface monitoring probe is monitored by a three-dimensional laser scanner to achieve its online monitoring in the x and y directions. The x direction is the transverse direction of the tunnel, and the y direction is the longitudinal direction of the tunnel.

[0012] Furthermore, the thrust rod is hollow inside, and a hole is arranged on the side wall near one end of the corbel-like component.

[0013] Furthermore, the thrust rods are located between the inner shield body and the outer shield body, and a plurality of thrust rods are evenly arranged along the circumferential direction.

[0014] Furthermore, an anti-instability triangular brace supporting the thrust rod is provided between the inner shield body and the outer shield body, and the support spacing between adjacent triangular braces is equal to the length of the shield machine model.

[0015] Furthermore, the hollowing range of the hollowing area is to

[0016] Furthermore, at the front end of the shield machine model to A slag blocking plate is arranged at the position, the slag blocking plate is arranged between the inner shield body and the outer shield body, and is located behind the local hollow area, and the space in front of the slag blocking plate forms a sealed space.

[0017] Furthermore, the tempered glass plate is polished and ground on all sides, and a smooth aluminum paper is placed on the inner surface, and vaseline is evenly applied on the surface of the aluminum paper to reduce the friction effect between the model box and similar formation materials.

[0018] Furthermore, the similar strata are simulated with quartz sand, mica, barite powder, river sand and cement to make them similar to the actual strata conditions, and the stratum model is cast in layers and compacted by manual vibration.

[0019] Compared with the prior art, the advantages and positive effects of the present invention are:

[0020] This plan mainly studies and designs the shield machine model. Through the nested inner and outer shields, combined with the design of thrust rods, the actual construction excavation process is simulated, and the surface settlement effect caused by shield construction is physically simulated in five dimensions through similar material simulation technology. This provides technical support for revealing and analyzing the spatial and temporal characteristics of surface settlement caused by shield tunnel construction, and determining the evolution law of surface settlement under the influence of shield step length and time effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of a similar simulation test system for five-dimensional effects of ground settlement caused by shield tunnel construction according to an embodiment of the present invention;

[0022] Figure 2 This is a plan view of the longitudinal settlement monitoring points according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the plan layout of lateral settlement monitoring points according to an embodiment of the present invention;

[0024] Figure 4 A schematic diagram of the arrangement of a three-dimensional scanning accuracy test according to an embodiment of the present invention;

[0025] Figure 5This is a schematic diagram of a precise control system for shield excavation equipment in a tunnel construction simulation test according to an embodiment of the present invention;

[0026] Figure 6 It is a schematic diagram of the thrust rod arrangement of the shield machine model according to an embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram of the structure of a shield machine propulsion model device according to an embodiment of the present invention;

[0028] Figure 8 Schematic diagram of a thrust rod anti-instability device for a shield machine model according to an embodiment of the present invention;

[0029] Fig. 9 This is a schematic diagram of a surface monitoring probe in a front view of a model box according to an embodiment of the present invention;

[0030] Among them, 1. box body; 2. inner shield body; 3. outer shield body; 31. partial hollow area; 4. corbel-like component; 41. embedded hole; 5. thrust rod; 6. jacking device; 7. slag vacuum cleaner; 8. electronic scale; 9. triangular support; 10. cutter head; 11. double-leg angle steel; 12. torque rod; 13. rotating motor; 14. AC power supply; 15. slag baffle. DETAILED DESCRIPTION

[0031] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein, and therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] Embodiment 1: This embodiment proposes a five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction, such as Figure 1 As shown, it includes a test model box, a test monitoring system and a shield machine model device;

[0033] The test model box includes a box body 1 with an upper opening, in which a similar stratum is simulated, the sides of the box body are made of tempered glass plates, the bottom of the box body is made of steel plates, adjacent tempered glass plates are connected by double-leg angle steels 11, and the sealing is improved by adding silicone structural sealant to prevent sand and water leakage. Among them, the model of the double-leg angle steel 11 needs to meet the requirements of the bending stiffness of the tempered glass plate, and minimize the displacement of the surface point caused by the deflection of the tempered glass plate. In this embodiment, the equilateral angle steel model of 20mmX20mmX3mm is preferably used, and the equilateral angle steel model can be appropriately increased according to the actual situation.

[0034] In addition, the boundary conditions of the test model box should ensure that the shear stress is 0 in addition to the lateral displacement being 0. In this embodiment, the tempered glass plate is polished and ground on all sides, and smooth aluminum paper is placed on the surface. When in use, vaseline is evenly applied on the surface of the aluminum paper to reduce the friction between the model box and similar materials.

[0035] In this embodiment, when making the outer frame of the model according to the three-dimensional diagram of the model and performing a similar simulation design of the stratum in the test model box, this test system uses quartz sand, mica, barite powder, river sand, cement and other materials to simulate the stratum rock material to make it similar to the actual stratum conditions. The stratum model is cast in layers and compacted by manual vibration.

[0036] The test monitoring system uses a three-dimensional laser scanner. The test mainly monitors surface settlement. Multiple surface monitoring points are arranged on the surface of the simulated stratum of the test model box. The surface monitoring points are set to ensure that they are evenly distributed in the vertical and horizontal directions and are not affected by boundary conditions. The starting point and the end point are far away from the boundary of the model box. The surface monitoring points are arranged as follows: Figure 2 and Figure 3 As shown, this embodiment is described by taking 3 rows arranged vertically and 3 rows arranged horizontally as an example. During specific implementation, it can be arranged according to specific laboratory site requirements.

[0037] The specific content is to set up three rows of surface lateral settlement monitoring points numbered a i，j The longitudinal monitoring points are set up in three rows numbered b m，n , used to observe the evolution of the surface sedimentation trough in the horizontal and vertical images, and set up surface monitoring probe devices at the surface monitoring points, such as Fig. 9 As shown in the figure, M is the state of the probe at the surface monitoring point after the surface deformation, and N is the state of the probe at the surface monitoring point before the surface deformation. By monitoring the displacement of the needle tip through a three-dimensional laser scanner, its online monitoring in the x and y directions can be realized. The length of the probe can realize the following three functions. First, the displacement effect in the x and y directions is coupled with the displacement effect caused by the surface inclination, and then the formula Δy=Δy 测 -Lsinθ removes the displacement caused by the inclination, where θ is the angle between the pointer position and the vertical direction after movement, and this angle is equal to the inclination caused by the movement of the surface, and L is the length of the probe, which means that the real displacement can be inversely calculated (the x direction is the horizontal direction of the tunnel, and the y direction is the longitudinal direction of the tunnel). Second, the measurement of the probe is easier than the measurement of the surface point, and the probe can serve as an identification. Third, it can accurately reflect the law of the change of the surface inclination, which is a crucial quantity for the further enrichment and development of the five-dimensional theory.

[0038] When determining the resolution of a 3D laser scanner, the measurement accuracy of the scanner at different resolutions is first studied. This embodiment uses Focus s150 scanner to conduct accuracy test, four flat target papers of 0.16mX0.12m are pasted on the wall, such as Figure 4 As shown. Secondly, the distances of AB, BC, and BD were measured with a total station, and then stations were set up at 10, 20, 30, 40, and 50 meters from the wall for scanning. Two resolutions were used for each station, namely the instrument default resolution 4X1 / 4 and the high-precision resolution 2X1 / 2. Five scans were performed at each resolution, and the distance error curves of AB, BC, and BD at different resolutions were drawn. By comparing the instrument error range through fitting the error curve, a resolution suitable for the test plan was selected. In general, when scanning at the same resolution, the closer the scanning distance, the smaller the measurement error and the higher the scanning accuracy. For the same scanning distance, the higher the resolution, the smaller the measurement error and the higher the scanning accuracy.

[0039] like Figure 5 and Figure 6 As shown, the shield machine model proposed in this embodiment adopts a double shield mode, including a nested inner shield 2 and an outer shield 3. The inner shield 2 and the outer shield 3 are both made of cold-bent thin-walled steel plates whose strength and rigidity meet the tunneling requirements of the shield machine. The outer shield 3 is set to be hollowed out within a certain range in the front of the shield machine (the front of the outer shield 3 is a local hollow area 31), and the preferred hollowing range is 1 / 4 of the length of the shield machine model. to The inner shield 2 is not hollowed out and is fully closed, while the outer shield 3 is hollowed out to simulate the ground loss during the actual shield construction process. During the test, the overlying soil is disturbed, and part of the soil can enter the inner shield 2 through the hollowing of the outer shield 3 of the shield machine.

[0040] In addition, at the front end of the shield machine model to A closed slag retaining plate 15 is provided at the position, and the slag retaining plate 15 is provided between the inner shield body 2 and the outer shield body 3, and is located behind the local hollow area 31. The functions of the closed slag retaining plate 15 are: first, to prevent the front end slag from leaking to the rear end, so as to better simulate the settlement caused by the advancement process and facilitate the measurement of soil loss; second, to provide a closed space to effectively improve the slag suction capacity of the slag vacuum cleaner.

[0041] Continue to refer Figure 5 and Figure 6 A bracket-like member 4 is provided between the inner shield body 2 and the outer shield body 3, and is welded to the inner side of the outer shield body 3 of the shield machine. Figure 6As shown, an embedding hole 41 is set in the middle, and the embedding hole 41 is used to fix the metal thrust rod 5. The thrust rod 5 is hollow inside, and a hole is set on the side wall near one end of the corbel-like member 4; the thrust rod 5 is located between the inner shield body 2 and the outer shield body 3, and one is set every 90 degrees along the four directions of the circumference. The other end of the thrust rod 5 is connected to the jacking device 6, and the jacking device 6 is also connected to the slag vacuum cleaner 7 to ensure uniform thrust during the shield machine's excavation and avoid causing the shield machine to deviate from the predetermined trajectory.

[0042] Among them, the thrust rod 5 has two functions. On the one hand, it is connected to the external jacking device 6 to provide forward thrust for the excavation of the shield machine. On the other hand, the end of the thrust rod 5 is also connected to the slag vacuum cleaner 7, which can timely suck out the slag between the inner and outer shield bodies through the slag vacuum cleaner 7 through the front hole of the metal thrust rod 5. The slag vacuum cleaner 7 is placed on an electronic scale 8. The indication of the electronic scale 8 can accurately control the stratum loss rate of each ring of shield advancement. At the same time, it can also play the function of timely removing the slag between the inner and outer shield bodies, so as to avoid the inner and outer shield bodies being filled with soil after advancing several rings, resulting in the subsequent stratum loss that cannot be simulated.

[0043] In particular, because the thrust of this shield machine model is applied by four metal thrust rods 5 with holes, in order to prevent the thrust from being subjected to excessive pressure and causing Euler yield, an anti-instability triangular support 9 of the metal thrust rods 5 is arranged in the shield body, such as Figure 8 As shown, the support spacing of the triangular support 9 is taken as the length of the shield machine model.

[0044] A rotatable cutterhead 10 is arranged at the front of the shield machine, and a cutting tool is attached to the cutterhead 10. The rotation of the cutterhead 10 to cut the soil is realized by a torque rod. The cutterhead of the shield machine is welded to the torque rod 12, and the end of the torque rod 12 is connected to a rotating motor 13. The rotating motor 13 is connected to an AC power supply 14. The torque rod 12 is driven by the rotation of the rotating motor 13, thereby driving the cutterhead 10 to rotate and cut the soil.

[0045] In summary, the test system designed in this embodiment simulates the shield machine, strata, etc., and arranges surface monitoring points to simulate surface settlement. It can effectively and intuitively observe the settlement law of the surface during the advancement of the shield machine. It can not only verify surface settlement theories such as random medium theory and Peck formula, but also is of great help to the risk assessment of shield tunnel construction in engineering, scientific prevention and effective control measures of surface settlement in subway tunnel construction, etc.

[0046] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction, including a test model box, a test monitoring system and a shield machine model device. The test model box is used to simulate actual construction geological conditions. It is characterized by: The shield machine model adopts a double shield mode, including a nested inner shield (2) and outer shield (3), a thrust rod (5), a jacking device (6) and a slag dust collector (7); the front of the outer shield (3) is a local hollow area (31); a quasi-corbel component (4) is arranged between the inner shield (2) and the outer shield (3); one end of the thrust rod (5) is fixed on the quasi-corbel component (4), and the other end is connected to the jacking device (6); the jacking device (6) is also connected to the slag dust collector (7); and the slag dust collector (7) is placed on an electronic scale (8); A cutterhead (10) with a tool attached is arranged at the front of the shield machine model. The cutterhead (10) is connected to a rotating motor (13) via a torque rod (12). The rotating motor (13) is connected to an AC power source (14). The torque rod (12) is driven by the rotation of the rotating motor (13), thereby driving the cutterhead (10) to rotate and cut soil.

2. The five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction according to claim 1 is characterized by: The test model box comprises a box body (1) with an upper opening, in which a similar stratum is simulated, the sides of the box body are made of tempered glass plates, the bottom of the box body is made of steel plates, adjacent tempered glass plates are connected by double-leg angle steels (11), and the sealing performance is improved by using sealant.

3. The five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction according to claim 1 is characterized by: The test monitoring system adopts a three-dimensional laser scanner to monitor surface settlement. A plurality of surface monitoring points are arranged on the surface of the simulated stratum of the test model box, and surface monitoring probes are set on the surface monitoring points. The surface monitoring points are arranged both vertically and horizontally. The starting point and the ending point are both far away from the boundary of the model box and are not affected by the boundary conditions. The displacement of the needle tip of the surface monitoring probe is monitored by the three-dimensional laser scanner to realize its online monitoring in the x and y directions, where the x direction is the transverse direction of the tunnel and the y direction is the longitudinal direction of the tunnel.

4. The five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction according to claim 1 is characterized by: The thrust rod (5) is hollow inside, and a hole is arranged on the side wall near one end of the corbel-like component (4).

5. The five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction according to claim 1 is characterized by: The thrust rods (5) are located between the inner shield body (2) and the outer shield body (3), and a plurality of thrust rods (5) are evenly arranged along the circumferential direction.

6. The five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction according to claim 2 is characterized by: An anti-instability triangular support (9) for supporting the thrust rod (5) is also provided between the inner shield body (2) and the outer shield body (3), and the support spacing between adjacent triangular supports (9) is equal to the length of the shield machine model.

7. The five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction according to claim 1 is characterized by: The hollowing range of the hollowing area (31) is to 8. The five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction according to claim 1 is characterized by: At the front end of the shield machine model to A slag blocking plate (15) is arranged at the position, the slag blocking plate (15) is arranged between the inner shield body (2) and the outer shield body (3), and is located behind the local hollow area (31), and the space in front of the slag blocking plate (15) forms a sealed space.

9. The five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction according to claim 2 is characterized by: The tempered glass plate is polished and ground on all sides, and a smooth aluminum paper is placed on the inner surface, and vaseline is evenly applied on the surface of the aluminum paper.

10. The five-dimensional spatial effect test and monitoring system for surface settlement caused by dual-mode shield construction according to claim 9 is characterized by: The similar strata are simulated by quartz sand, mica, barite powder, river sand and cement, and the stratum model is cast in layers and compacted by manual vibration.

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