Subway tunnel shield model test system

Abstract

The invention relates to the technical field of shield simulation, and particularly discloses a subway tunnel shield model test system which comprises a model box, an excavation module, an acquisition module, an analysis module and a verification module. Wherein the analysis module compares images of the observation window before and after the model test to determine the displacement of the dyed test soil and judges whether the fluctuation characteristics exist in the heave data collected by the collection module according to the comparison result, and the verification module responds to the existence of the fluctuation characteristics, compares the displacement of the dyed test soil with the displacement of the nearest displacement sensor, and determines the displacement of the dyed test soil. Generating a fluctuation verification result of the heaving and sinking data to evaluate the characterization capability of the heaving and sinking data for a single simulation test; by analyzing the position change of the dyeing belt and comparing with the parameters of the displacement sensor, whether the collected data of the displacement sensor can represent the overall change condition of the test soil or not can be effectively verified, the state that the collected information does not have the characterization can be found in time, information misalignment is avoided, and the model test has higher reliability.

Description

Technical Field

[0001] The invention relates to the technical field of shield simulation, and in particular to a subway tunnel shield model test system. Background Art

[0002] The shield method construction technology has the advantages of high degree of mechanization, relatively safe construction, and little disturbance to the surrounding environment. It has been widely used in urban rail transit, underground integrated pipeline corridors, hydraulic tunnels and other fields. The shield method is a fully mechanized construction method in the dark excavation method. It pushes the shield machine into the ground, supports the surrounding rock with the shield shell and segments to prevent collapse into the tunnel, and excavates the soil in front of the excavation face with a cutting device. The soil is transported out of the cave by the excavation machinery, and is pressurized and pushed forward at the rear by the jack, and prefabricated concrete segments are assembled to form a mechanized construction method of the tunnel structure. It is widely used in urban traffic tunnel construction. Considering that it is difficult to obtain data through on-site monitoring, and full-scale test research has the defects of huge cost and poor operability, it is particularly important to use model test methods to study the transverse and longitudinal mechanical response laws and deformation and failure characteristics of shield tunnels under special working conditions.

[0003] Existing model tests often consider the deformation analysis of the tunnel after shield tail grouting and the stress analysis of the surrounding soil during tunnel excavation without considering the grouting conditions. The process of synchronous grouting after the installation of the pipe segment during the excavation process is ignored. It is quite different from the on-site construction process and somewhat inconsistent with the actual working conditions. At present, the common method of shield tail grouting test is that the shield shell is sleeved outside the pipe segment, the cylindrical pipe segment is a whole, there are grouting holes on the shield shell wall, the shield shell and the pipe wall are buried in the soil in advance, and then grouting is carried out, ignoring the excavation process. Without considering the tunnel excavation under grouting conditions, the pipe segment is fixed at the end of the cutterhead in advance, and the cutterhead and the pipe segment are pushed forward at the same time, ignoring the process of synchronous grouting. The stratum loss during the shield machine excavation process is the biggest influencing factor of surface settlement, and grouting is an effective measure to reduce stratum loss. In addition, in the prior art, there is a lack of further analysis on the accuracy of shield simulation data, and thus there is a large data error phenomenon, which cannot effectively guarantee the accuracy of the collected data. Summary of the invention

[0004] The purpose of the present invention is to provide a subway tunnel shield model test system to solve the problem that the prior art lacks further analysis on the accuracy of shield simulation data, resulting in large data errors and the inability to effectively guarantee the accuracy of collected data.

[0005] To this end, the present invention provides a subway tunnel shield model test system, which includes a model box, an excavation module, a collection module, an analysis module and a verification module.

[0006] The model box is filled with test soil, one side of the model box in the left and right directions is provided with a through hole for simulating excavation, and the front side of the model box is provided with a plurality of observation windows, each of which is distributed in a rectangular shape; a spraying assembly is provided in the middle of the height direction of the observation window, for dyeing the test soil, and the dyed test soil is displayed as a horizontal dyeing band in the observation window; the excavation module is used to simulate excavation of the test soil in the model box;

[0007] The acquisition module of the present invention includes a plurality of displacement sensors and cameras arranged in the model box, wherein the displacement sensors and the cameras are respectively used to acquire the heave and settlement data of the soil in the model box and the images of each observation window; the analysis module is connected to the acquisition module, and is used to compare the images of the observation window before and after the model test to determine the displacement of the dyed test soil, and determine whether the heave and settlement data has fluctuation characteristics according to the comparison results; the verification module is respectively connected to the acquisition module and the analysis module, and the verification module compares the displacement of the dyed test soil with the displacement of the nearest displacement sensor in response to the existence of the fluctuation characteristics, and generates a fluctuation verification result of the heave and settlement data to evaluate the characterization capability of the heave and settlement data for a single simulation test; the output module is used to output the heave and settlement data and the fluctuation verification result.

[0008] As a preferred technical solution for the subway tunnel shield model test system, the analysis module compares the images of the observation window before and after the model test to determine the number of breakpoints of the dyeing band and the maximum displacement difference;

[0009] The number of breakpoints is the number of discontinuous places of the dyed test soil that appear after the model test, and the maximum displacement difference is the elevation distance between the highest point and the lowest point of the dyed test soil.

[0010] As a preferred technical solution for the subway tunnel shield model test system, the analysis module determines that the heave and subsidence data have fluctuation characteristics in response to the number of breakpoints or the maximum displacement difference of the dyeing band being greater than a corresponding threshold.

[0011] As a preferred technical solution for the subway tunnel shield model test system, the verification module obtains the position of the test soil where the maximum displacement difference exceeds the corresponding threshold, and determines the nearest displacement sensor according to the position.

[0012] As a preferred technical solution for the subway tunnel shield model test system, the verification module generates the fluctuation verification result according to the position of the test soil where each maximum displacement difference exceeds the corresponding threshold value, and the corresponding heave and sink data of the nearest displacement sensor;

[0013] The fluctuation verification result includes the displacement of the part of the test soil corresponding to the maximum displacement difference and the displacement of the nearest displacement sensor in each observation window after the simulation test, as well as the absolute value of the displacement difference between the two.

[0014] As the preferred technical solution for the subway tunnel shield model test system, the excavation module includes:

[0015] The shield simulation unit is used to simulate excavation of the test soil in the model box and discharge the slag generated by the simulated excavation;

[0016] The grouting unit is used for simulating the grouting forming of the tunnel, and the grouting unit comprises a grouting pipe.

[0017] As a preferred technical solution for the subway tunnel shield model test system, the shield simulation unit includes a cutter head, a shield shell and a screw conveyor connected in sequence;

[0018] The cutter disc cuts the test soil in front by rotating, the shield shell moves forward synchronously with the cutter disc, and the screw conveyor extends into the shield shell to discharge the residue cut by the cutter disc.

[0019] As a preferred technical solution for the subway tunnel shield model test system, the shield shell is a tubular structure, the inner wall of the shield shell is provided with grouting holes, the rear end face of the shield shell is provided with grouting holes, and the grouting holes are connected to the grouting pipe.

[0020] As a preferred technical solution for the subway tunnel shield model test system, the excavation module also includes a plurality of pipe segments, each pipe segment is matched to form a ring and the outer diameter of the ring matches the inner diameter of the shield shell.

[0021] As a preferred technical solution for the subway tunnel shield model test system, two grooves are arranged on the inner wall of the segment at intervals.

[0022] The beneficial effects of the present invention are:

[0023] The invention provides a subway tunnel shield model test system. The subway tunnel shield model test system comprises an observation window on a model box and a spraying assembly arranged on the observation window. The system can spray a test soil near the observation window to form a visual dyeing band. By analyzing the position change of the dyeing band and comparing it with the parameters of a displacement sensor, it can be effectively verified whether the collected data of the displacement sensor can represent the overall change of the test soil, and the state in which the collected information is not representative can be discovered in time to avoid information inaccuracy, thereby having higher reliability for the model test.

[0024] Furthermore, the present invention closely combines shield excavation, segment installation and grouting, and can take into account the stratum loss caused by soil excavation, thus greatly avoiding the interference of manual excavation on the test results. By establishing similar models or tests, the nature and laws of practical problems can be better understood. The displacement and stress change laws of the soil around the segments can be intuitively reflected and verified, which is helpful for the discussion of tunnel topics and the analysis of shield information. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural block diagram of a subway tunnel shield model test system in an embodiment of the present invention;

[0026] Figure 2 It is a structural schematic diagram of a subway tunnel shield model test system in an embodiment of the present invention;

[0027] Figure 3 It is a structural schematic diagram of a model box in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of the shield in an embodiment of the present invention;

[0029] Figure 5 is a schematic diagram of a pipe segment in an embodiment of the present invention;

[0030] Figure 6 Schematic diagram of a cutter disc in an embodiment of the present invention.

[0031] In the figure: 1, model box; 11, through hole; 12, observation window; 13, box door;

[0032] 2. Knife plate;

[0033] 3. Shield shell; 31. Slurry outlet hole;

[0034] 4. Earth warehouse;

[0035] 5. Tube segment; 51. Groove;

[0036] 6. Putting;

[0037] 7. Rotating motor;

[0038] 8. Reaction frame;

[0039] 9. Conveying motor;

[0040] 10. Segment splicing mechanism. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0045] See also Figure 1-3 As shown, this embodiment provides a subway tunnel shield model test system, which includes a model box 1, an excavation module, a collection module, an analysis module and a verification module.

[0046] The model box 1 is filled with test soil. A through hole 11 for simulating excavation is provided on one side of the model box 1 in the left and right directions. A plurality of observation windows 12 are provided on the front side of the model box 1. Each observation window 12 is distributed in a rectangular shape. A spraying assembly (not shown in the figure) is provided in the middle of the height direction of the observation window 12 to dye the test soil. The dyed test soil is displayed as a horizontal dyeing band in the observation window 12. The excavation module is used to simulate excavation of the test soil in the model box 12. In implementation, the model box can be configured with Figure 2The box door 13 shown has an observation window 12 disposed on the box door 13, which can provide convenience for the test operation.

[0047] In this embodiment, the acquisition module includes a plurality of displacement sensors arranged in the model box, and a camera, wherein the displacement sensor and the camera are respectively used to collect the heave and settlement data of the soil in the model box and the images of each observation window; the analysis module is connected to the acquisition module, and is used to compare the images of the observation window before and after the model test to determine the displacement of the dyed test soil, and determine whether there is a fluctuation feature in the heave and settlement data according to the comparison result; the verification module is respectively connected to the acquisition module and the analysis module, and the verification module compares the displacement of the dyed test soil with the displacement of the nearest displacement sensor in response to the existence of the fluctuation feature, and generates a fluctuation verification result of the heave and settlement data to evaluate the characterization capability of the heave and settlement data for a single simulation test; the output module is used to output the heave and settlement data and the fluctuation verification result.

[0048] In the above embodiment, through the observation window on the model box and the spraying assembly arranged on the observation window, a visual dyeing band can be sprayed on the test soil near the observation window. By analyzing the position change of the dyeing band and comparing it with the parameters of the displacement sensor, it can be effectively verified whether the collected data of the displacement sensor can represent the overall change of the test soil, and the state where the collected information is not representative can be discovered in time to avoid information distortion, which has higher reliability for the model test. At the overall level, shield excavation, segment installation and grouting are closely combined, and the stratum loss caused by soil excavation can be considered, which greatly avoids the interference of artificial excavation on the test results. Establishing similar models or experiments can better understand the nature and laws of actual problems. It can intuitively reflect and verify the displacement and stress change laws of the soil around the segments, which is helpful for the discussion of tunnel topics and the analysis of shield information.

[0049] In detail, the spray assembly in the above embodiment can be realized by burying a row of nozzles horizontally in the transparent layer of the observation window, and by designing the pipeline so that each nozzle is connected to a pump body and a dye cartridge, the dyeing of the test soil can be achieved.

[0050] In this embodiment, the dimensions of the model box are 4 m in length, 3 m in width, and 3 m in height, and the radius of the through hole is 0.6 m.

[0051] After the model test is completed, the analysis module compares the images of the observation window before and after the model test to determine the number of breakpoints of the dyeing band and the maximum displacement difference;

[0052] The number of breakpoints is the number of discontinuities in the dyed test soil that appear after the model test, and the maximum displacement difference is the elevation distance between the highest and lowest points of the dyed test soil.

[0053] The analysis module responds to the number of breakpoints or the maximum displacement difference of the dyed band being greater than the corresponding threshold value to determine that the heave and subsidence data have fluctuation characteristics. The discontinuity of the dyed band due to excavation displacement and the large elevation displacement can both illustrate the complexity of the excavation simulation process. The setting of the corresponding thresholds for the two needs to be set in combination with the actual working conditions (such as the size of the model box and the observation window).

[0054] As for the fluctuation characteristics, it reflects the degree of change of the soil after excavation and can characterize the volatility of the simulation data. Under the premise of volatility, the sensor data's ability to display the overall state is questionable. Therefore, the location of the test soil where the maximum displacement difference exceeds the corresponding threshold is obtained through the verification module, and the nearest displacement sensor is determined based on the location. The uplift and sinking trend of the sensor that is close to the abnormal location should be the same as that of the abnormal location. The fluctuation verification result is generated based on the location of the test soil where the maximum displacement difference exceeds the corresponding threshold, and the corresponding uplift and sinking data of the nearest displacement sensor;

[0055] Among them, the fluctuation verification results include the displacement of the part of the test soil corresponding to the maximum displacement difference and the displacement of the nearest displacement sensor in each observation window after the simulation test, as well as the absolute value of the displacement difference between the two. The larger the absolute value of the displacement difference, the less representative the simulation results are, and more displacement sensors need to be added accordingly to obtain more representative heave and settlement data.

[0056] In this embodiment, the excavation module specifically includes:

[0057] The shield simulation unit is used to simulate excavation of the test soil in the model box and discharge the slag generated by the simulated excavation;

[0058] The grouting unit is used to simulate the grouting forming of the tunnel, and the grouting unit includes a grouting pipe.

[0059] Please combine Figure 2-Figure 6 As shown, the shield simulation unit includes a cutter head 2 and a shield shell 3 connected in sequence (the shield shell 3 is Figure 2 Not shown in the figure, the shield shell 3 is coaxial with the cutter disc 2 and assembled behind the cutter disc 2) and a screw conveyor, as well as a rotating motor 7 that provides rotational power to the cutter disc 2. The rotating motor 7 is fixedly connected to a pipe segment splicing mechanism 10 for fixing the pipe segments. The forward propulsion of the cutter disc 2 is achieved through the actuation of multiple push rods 6. The end of the push rod is connected to a reaction frame 8 to provide support for the actuation of the push rod 6.

[0060] The screw conveyor includes a soil bin 4 for temporarily storing the slag and a conveying motor 9 for providing conveying power;

[0061] Among them, the cutter disc 2 cuts the test soil in front by rotating and advancing, the shield shell 3 moves forward synchronously with the cutter disc 2, and the screw conveyor extends into the shield shell 3 to discharge the slag cut by the cutter disc 2 in the soil bin, and there is a soil pressure balance sensor in the soil bin 4 to facilitate the adjustment of the speed. In detail, in this embodiment, the cutter disc 2 is a spoke plate type, and the advancing side of the cutter disc 2 is provided with a sawtooth made of stainless steel, the opening rate is 45%, and the outer diameter of the cutter disc is 0.5m, which is 1 / 6 of the size of the prototype shield of the on-site engineering. The cutter disc 2, the shield shell 3 and the screw conveyor are all independently actuated. In this embodiment, the speed accuracy of the rotating motor is 0.1r / min, and the maximum output torque is 100kN·m. The propulsion is carried out by an electrically driven push rod. The design thrust is 12KN, a total of 8, the stroke is 3m, and the forward speed accuracy is 0.1mm / min. The screw conveyor adopts an axis tree type, and its outer diameter is 64mm. The screw conveyor can output soil particles with a maximum particle size of 10mm. The speed of the conveying motor is adjustable within the range of 0-50 r / min, and the maximum torque is 60 N·m. As for the grouting unit, it is a prior art that can control the grouting into the grouting hole, so it is not described in detail.

[0062] Continue reading Figure 4 As shown, the shield shell 3 is a tubular structure, the inner wall of the shield shell 3 is provided with a grouting hole, the rear end surface of the shield shell 3 is provided with a grouting hole 31, and the grouting hole is connected to the grouting pipe of the grouting unit.

[0063] Continue reading Figure 5 As shown, the excavation module also includes a number of segments 5, each of which is annular after being matched, and the outer diameter of the ring matches the inner diameter of the shield shell 3. In this embodiment, the segment width is 30mm, the outer diameter is 986mm, and the thickness is 93mm. The material is C30 precast concrete. It is made by a mold. Each segment is assembled close to the inner wall of the shield shell. After the assembly is completed, synchronous grouting is performed at the shield tail. Before installing the segment, an adhesive is applied to the joints of each part. The purpose of the adhesive is to replace the bolt structure between the segments at the construction site for stability. The segment is a symmetrical structure. The inner wall of each segment has a groove 51 with a length of 200mm, a width of 100mm, and a depth of 30mm. Its function is to facilitate the placement of the segment structure.

[0064] The block diagram in the accompanying drawings illustrates the possible architecture, function and operation of the device, method and computer program product according to various embodiments of the present application. In this regard, each box in the block diagram can represent a part of a module, a program segment or a code, and the part of the module, the program segment or the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram, and the combination of the boxes in the block diagram and / or the flow chart can be implemented with a dedicated hardware-based device that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0065] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A subway tunnel shield model test system, characterized in that: include: A model box, wherein the model box is filled with test soil, a through hole for simulating excavation is provided on one side of the model box in the left and right directions, and a plurality of observation windows are provided on the front side of the model box, each of which is distributed in a rectangular shape; Wherein, a spraying assembly is provided in the middle of the height direction of the observation window, which is used to dye the test soil, and the dyed test soil is displayed as a horizontal dyeing band in the observation window; An excavation module, used for simulating excavation of the test soil in the model box; The acquisition module includes a plurality of displacement sensors and cameras arranged in the model box, wherein the displacement sensors and the cameras are used to respectively acquire the heave and sink data of the soil in the model box and the images of each observation window; An analysis module, connected to the acquisition module, for comparing the images of the observation window before and after the model test to determine the displacement of the dyed test soil, and judging whether the heave and subsidence data has fluctuation characteristics according to the comparison result; A verification module, connected to the acquisition module and the analysis module respectively, wherein the verification module compares the displacement of the dyed test soil with the displacement of the nearest displacement sensor in response to the existence of the fluctuation feature, and generates a fluctuation verification result of the heave and subsidence data to evaluate the characterization capability of the heave and subsidence data for a single simulation test; An output module is used to output the heave data and the fluctuation verification result.

2. The subway tunnel shield model test system according to claim 1 is characterized in that: The analysis module compares the images of the observation window before and after the model test to determine the number of breakpoints of the dyeing band and the maximum displacement difference; The number of breakpoints is the number of discontinuous places of the dyed test soil that appear after the model test, and the maximum displacement difference is the elevation distance between the highest point and the lowest point of the dyed test soil.

3. The subway tunnel shield model test system according to claim 2 is characterized in that: The analysis module determines that the heave data has fluctuation characteristics in response to the number of breakpoints or the maximum displacement difference of the dyeing band being greater than the corresponding threshold.

4. The subway tunnel shield model test system according to claim 3 is characterized in that: The verification module obtains the position of the test soil where the maximum displacement difference exceeds the corresponding threshold value, and determines the nearest displacement sensor according to the position.

5. The subway tunnel shield model test system according to claim 4 is characterized in that: The verification module generates the fluctuation verification result according to the position of the test soil where each maximum displacement difference exceeds the corresponding threshold value and the corresponding heave and settlement data of the nearest displacement sensor; The fluctuation verification result includes the displacement of the part of the test soil corresponding to the maximum displacement difference and the displacement of the nearest displacement sensor in each observation window after the simulation test, as well as the absolute value of the displacement difference between the two.

6. The subway tunnel shield model test system according to claim 1, characterized in that: The excavation module comprises: The shield simulation unit is used to simulate excavation of the test soil in the model box and discharge the slag generated by the simulated excavation; The grouting unit is used for simulating the grouting forming of the tunnel, and the grouting unit comprises a grouting pipe.

7. The subway tunnel shield model test system according to claim 6, characterized in that: The shield simulation unit comprises a cutter head, a shield shell and a screw conveyor connected in sequence; The cutter disc cuts the test soil in front by rotating, the shield shell moves forward synchronously with the cutter disc, and the screw conveyor extends into the shield shell to discharge the residue cut by the cutter disc.

8. The subway tunnel shield model test system according to claim 7 is characterized in that: The shield shell is a tubular structure, the inner wall of the shield shell is provided with a grouting hole, the rear end surface of the shield shell is provided with a grouting hole, and the grouting hole is connected to the grouting pipe.

9. The subway tunnel shield model test system according to claim 8, characterized in that: The excavation module also includes a plurality of pipe segments, each of which forms a ring after being matched, and the outer diameter of the ring matches the inner diameter of the shield shell.

10. The subway tunnel shield model test system according to claim 9, characterized in that: The inner wall of the tube sheet is provided with two grooves at intervals.

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