Simulated tunneling method and device for active jacking of close-to-underpassing existing structure

Abstract

The application discloses a kind of simulation tunneling tunnel active jacking device and method that underpass existing structure is closely attached, including experiment box, the top of experiment box is fixed with the hopper for adding soil body to test box, the bottom of the hopper is provided with discharge port, and hopper can move along the top of experiment box under the driving of driving device;Jacking device is fixed in experiment box, the jacking device is used to apply upward jacking force to the existing structure embedded in box, and the jacking device is connected to control system, for controlling the size of jacking force and the sequence of jacking.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of rail transit engineering, and particularly relates to a device and method for simulating active jacking of a tunnel under existing tunnel. BACKGROUND

[0002] The construction of a new tunnel closely underpassing an existing tunnel is complicated, and the settlement control of the existing structure is difficult, so it is of great significance to master the construction mechanical behavior of the new tunnel closely underpassing the existing tunnel for improving the safety of tunnel construction. Model test is an effective method for exploring the construction mechanical behavior of the new tunnel closely underpassing the existing tunnel, and there is no test device for simulating active jacking of the new tunnel closely underpassing the existing tunnel. SUMMARY

[0003] In view of the deficiencies in the prior art, the purpose of the present application is to provide a device and method for simulating active jacking of a tunnel under existing structure, which aims to simulate the change law of the existing structure in the process of jacking and supporting when the tunnel underpassing the existing tunnel.

[0004] In order to achieve the above-mentioned purpose, the present application is realized by the following technical scheme:

[0005] In the first aspect, the embodiment of the present application provides a device for simulating active jacking of a tunnel under existing structure, comprising an experimental box, a hopper for adding soil into the experimental box is fixed on the top of the experimental box, the bottom of the hopper is provided with a discharge port, and the hopper can move along the top of the experimental box under the driving of a driving device; a jacking device is fixed in the experimental box, the jacking device is used for applying upward jacking force to the existing structure embedded in the box, and the jacking device is connected with a control system for controlling the size of the jacking force and the sequence of jacking.

[0006] As a further technical scheme, a plurality of longitudinal and transverse sliding rails are installed in the bottom of the experimental box, and a sliding block matched with the sliding rails is installed at the bottom of the jacking device.

[0007] As a further technical scheme, a clamping groove and a moving block are arranged in the sliding block, a fastening bolt is arranged on the side surface of the sliding block, and the distance between the moving block and the inner side surface of the sliding block can be adjusted by adjusting the fastening bolt, so as to fix the sliding block on the sliding rail.

[0008] As a further technical scheme, an axial force meter is arranged at the top of the jacking device.

[0009] As a further technical scheme, a magnetic suction base is further arranged at the top of the jacking device, and the magnetic suction base is connected with a steel plate.

[0010] As a further technical scheme, the driving device comprises a motor, chain wheels are arranged on four corners of the top of the test box, and a chain wheel is also arranged on one side of the test box, and the motor drives the hopper to move back and forth on the top of the test box through a transmission chain and the chain wheels.

[0011] In a second aspect, the embodiment of the present application based on the above-mentioned simulation of the active jacking experiment device of the tunneling under the existing structure, further provides an experimental method, comprising the following steps:

[0012] Step 1: determine the direction of the tunnel excavation, and determine the position of the jacking support device accordingly;

[0013] Step 2: fix the jacking device at the position determined in step 1, and require that the top end of the jacking support device should be higher than the bottom of the excavated tunnel, connect the jacking support device to the control box, and connect the axial force of the jacking support device to the acquisition instrument;

[0014] Step 3: after fixing the jacking support device, add soil into the test box through the hopper;

[0015] Step 4: when the soil is added to the depth of the bottom surface of the existing structure, place the existing structure, and make the existing structure remain horizontal after being placed; after fixing the existing structure, continue to add soil until the soil surface reaches the corresponding position;

[0016] Step 5: open the door of the box, and perform the tunnel excavation work; divide the tunnel excavation area into four sections, and excavate from the inside to the outside; after the excavation of each section is completed, control the jacking support device at the corresponding position through the control box to perform jacking; when the top is about to abut against the existing structure, fix a steel plate on the top of the jacking support device, and continue to jacking until the jacking support device abuts against the bottom surface of the existing structure. Apply a layer of lime under the soil not supported by the jacking device to simulate the initial support and prevent the soil from falling and interfering with the experiment;

[0017] Step 6: repeat the construction process in step 5 until the excavation and jacking process of the excavation area are completed;

[0018] Step 7: after the experiment is completed, collect the data of the axial force meter, and finally obtain the construction mechanical behavior of the newly-built tunnel closely underpassing the existing tunnel.

[0019] The beneficial effects of the above-mentioned embodiments of the present application are as follows:

[0020] 1. In order to simulate the active jacking process of the tunneling under the existing tunnel, the present application discloses an experimental box, which is provided with a door on the side of the experimental box, and an automatic feeding hopper is designed on the top of the experimental box to uniformly add soil into the experimental box, and a jacking device is arranged to jacking the existing structure.

[0021] 2. The end of the jacking device in the application is provided with an axle force meter, which can collect the axle force received during the experiment. A magnetic suction base is provided on the top, and a steel plate is fixed outside the magnetic suction base. During the experiment, the steel plate plays a role of increasing the stress area and reducing stress concentration.

[0022] 3. The bottom of the experimental box in the application is provided with sliding rails, which cooperate with the sliding block at the bottom of the jacking device. The sliding block can be fixed at any position of the sliding rail through fastening bolts. The design of the sliding block and the sliding rail in the application can make the jacking support device firmly fixed on the bottom of the experimental box. Several sliding rails are distributed on the bottom of the box, and the fixed position of the jacking support device on the bottom of the box can be adjusted according to the direction of the simulated tunnel to conduct experiments under various working conditions. It has strong adaptability. Compared with the ordinary method of fixing the jacking device, the sliding rails in the application protrude from the bottom of the box, which can facilitate the cleaning of the bottom of the box.

[0023] 3. In the application, the hopper is fixed on the top of the experimental box, and fixed chains are arranged on both sides of the hopper. The chains are connected with the motor through transmission wheels. During the soil adding process, the soil can be first poured into the hopper, and the left and right movement of the hopper is controlled by the forward and reverse rotation of the motor. During the movement, the trapdoor below the hopper is opened, and the soil in the hopper is poured into the experimental box. The use of the hopper for soil adding process can make the soil evenly poured into the experimental box, reducing the workload during the surface flattening process. The bidirectional movement of the hopper controlled by the motor can improve the efficiency of soil adding.

[0024] 4. In the application, the control system controls the jacking process of the jacking support device. During the operation, different buttons on the control box are controlled to control the jacking of the jacking support device at the corresponding position. Through the control box, the jacking support devices at different positions can be controlled, so that the whole cycle of the experiment process is completed. BRIEF DESCRIPTION OF DRAWINGS

[0025] The drawings accompanying the specification of this application form a part thereof, serve to further provide a further understanding of the application, and together with the description of the exemplary embodiments of the application, serve to explain the application, and do not constitute an improper limitation of the application.

[0026] Figure 1 is the structural schematic diagram of the loading box in the application in a non-test state;

[0027] Figure 2 is the structural schematic diagram of the loading box in the application in a test state;

[0028] Figure 3 、 Figure 4 is the control box schematic diagram in the application;

[0029] Figure 5 、 Figure 6 is the jacking support device schematic diagram in the application;

[0030] Figure 7 、 Figure 8 is the fixed front and cross-sectional view of the jacking support device of the present application;

[0031] Figure 9 、 Figure 10 is the fixed front and cross-sectional view of the process of inserting the existing structure in the experimental device of the present application;

[0032] Figure 11 、 Figure 12 is the fixed front and cross-sectional view of the process of adding soil in the experimental device of the present application;

[0033] Figure 13 、 Figure 14 is the fixed front and cross-sectional view of the process of excavating the first section and supporting in the experimental device of the present application;

[0034] Figure 15 、 Figure 16 is the fixed front and cross-sectional view of the process of excavating and supporting in the experimental device of the present application;

[0035] In the figure: the mutual distance or size is exaggerated to show the position of each part, and the schematic view is only for illustration.

[0036] 1-steel plate, 2-organic glass plate, 3-shutter, 4-control box, 5-base, 6-slide rail, 7-acquisition box, 8-wire, 9-jacking simulation device, 10-hopper track, 11-chain, 12-drive wheel, 13-motor, 14-hopper, 15-soil body, 16-simulated existing structure, 17-wiring port, 18-control button, 19-sliding block, 20-oil pump, 21-hydraulic rod, 22-axial force meter, 23-magnetic suction base, 24-steel plate, 25-fastening bolt, 26-sliding block, 27-clamping groove. DETAILED DESCRIPTION

[0037] It should be noted that the following detailed description is illustrative only and is intended to provide further description of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0038] It is to be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments consistent with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0039] For the convenience of description, if "upper", "lower", "left" and "right" appear in the present application, they only mean the same direction as the upper, lower, left and right of the drawing itself, and do not limit the structure, but only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as a limitation on the present application.

[0040] As introduced in the background, there is no test device for simulating the new tunnel closely underpassing the existing tunnel active underpinning at present, and the present application proposes a simulation device, which can directly and accurately simulate the whole process of the method.

[0041] In a typical embodiment of the present application, as shown in Figures 1-16 , the experimental device disclosed in the embodiment includes an experimental box, a hopper for adding soil into the experimental box is fixed on the top of the experimental box, the bottom of the hopper is provided with a discharge port, and the hopper can move along the top of the experimental box under the driving of a driving device; a jacking device is fixed in the experimental box, the jacking device is used for applying upward jacking force to the existing structure embedded in the box, the jacking device is connected with a control system for controlling the size of the jacking force and the sequence of jacking; a side door for later excavation is arranged on the side of the experimental box.

[0042] Further, the experimental box in the embodiment includes a base 5, a box body and a top loading device, the box body is installed on the base 5, and the loading device is installed on the top of the box body; the box body is made of steel plates and organic glass plates 2, the front of the box body is the organic glass plate 2, and the other three sides are welded by the steel plates 1, so that the internal soil can effectively bear the pressure on the side wall of the loading box. At the same time, in order to facilitate the simulation of excavation, a flap (side door) is arranged on the steel plate at the back of the box body, and longitudinal and transverse sliding rails are arranged on the top of the base. The jacking support device is fixed on the sliding rails through the fixing device, and the jacking support device is connected with the control box through wires. Through the control box, the jacking process of the jacking support device can be controlled.

[0043] In order to facilitate the addition of soil into the experimental box during the experiment, a loading device is arranged on the top of the box body of the experimental box; in order to facilitate the operation, an iron chain is fixed on the side of the hopper, and the motor can drive the iron chain and the hopper to move through the transmission wheel, so that the soil can be uniformly added into the box body of the experimental box.

[0044] Further, the jacking support device described above plays a role in jacking the existing structure in the embodiment. As shown in Figure 5 , Figure 6As shown, the jacking support device in the embodiment can be divided into three parts, i.e. the sliding block 19, the hydraulic cylinder 20 and the driving rod 21; the end of the driving rod 21 is provided with an axial force meter 22, which can collect the axial force in the experimental process; the collecting box 7 is connected with the lead wire of the axial force meter 22, which can collect the data measured by the axial force meter in the experimental process; the top of the driving rod 21 is provided with a magnetic suction seat 23, and the outer side of the magnetic suction seat 23 is fixed with a steel plate 24, which can increase the stress area and reduce the stress concentration in the experimental process. In order to avoid the disturbance to the surrounding soil in the jacking process, the oil pump is relatively long.

[0045] The sliding block 19 is provided with a clamping groove 27 and a moving block 26, and the position of the moving block 26 can be adjusted by the fastening bolt. In use, the clamping groove 27 is clamped to the side of the sliding rail first, and then the fastening bolt 25 is tightened to fix the jacking support device on the sliding rail.

[0046] Further, in order to avoid the difficulty in cleaning the sand in the box after the experiment, the sliding rail of the box bottom protrudes from the bottom surface.

[0047] Further, in order to simplify the process of adding soil, the chain 11 on the side of the hopper 14 is connected with the motor through the chain wheel, and the lower part of the hopper 14 is provided with a valve, which can control the movement of the hopper by controlling the forward and reverse rotation of the motor.

[0048] Further, in order to reduce the disturbance to the surrounding soil in the jacking process in the experiment, the oil pump of the jacking support device is relatively long, which can ensure that it protrudes from the bottom surface of the excavated tunnel in the experiment. Further, in order to avoid the concentrated stress on the existing structure in the jacking process, a magnetic suction seat is arranged on the top of the hydraulic rod of the jacking support device, and a steel plate can be placed on the magnetic suction seat to increase the contact area during jacking. Further, in order to control the jacking of the jacking support device in different excavation sections, different buttons of the control box can control the jacking of the jacking support device at different positions.

[0049] In the operation process, after the position of the jacking support device is determined, the device is fixed on the sliding rail through the sliding block. The oil pump lead wire is connected with the control box, and the axial force meter lead wire is connected with the collecting box. In the experimental process, after the soil at the corresponding position is excavated, the hydraulic rod is jacked through the control box. In order to avoid the stress concentration phenomenon in the experimental process, a steel plate is placed on the magnetic suction seat when the jacking is about to reach the bottom of the existing structure. Then the jacking continues until the top of the steel plate reaches the bottom of the existing structure.

[0050] Before operation, the direction of tunnel excavation is determined first. After the position of the jacking support device is determined, the jacking support device is fixed. In the process of fixing the jacking support device, in order to reduce the disturbance to the surrounding soil in the jacking process, the top end of the oil pump should be higher than the bottom of the excavated tunnel to ensure that it can protrude during excavation.

[0051] And the shaft force meter of the jacking support device is connected with the acquisition box, and the wire of the oil pump is connected with the control box. After the connection is completed, the soil is added in the experimental box through the hopper, and the existing structure model is arranged in the soil. After the soil is added, the rear door is opened, and the tunnel excavation is carried out. During the excavation process, the jacking support device of the excavated area is controlled through the control box to complete the jacking process. When the jacking support device is about to contact the existing structure, a magnetic suction seat is installed to reduce stress concentration, and a steel plate is installed. After jacking, the data of the shaft force meter is collected. Until the whole process of tunnel excavation and jacking is completed, the experiment is completed.

[0052] The specific test process is as follows:

[0053] 1. First of all, the direction of tunnel excavation should be determined, and the position of the jacking support device should be determined accordingly.

[0054] 2. Through the sliding block and the sliding rail at the bottom of the box, the jacking support device is fixed to the bottom of the box through the sliding block and the sliding rail, and the fastening screws are tightened. In the process of fixing the jacking support device, in order to reduce the disturbance of the jacking process to the surrounding soil, the top of the oil pump should be higher than the bottom of the excavated tunnel to ensure that it can be stretched out during the excavation process. Connect the wire of the support device to the control box, and connect the wire led out by the shaft force meter to the acquisition instrument.

[0055] 3. After fixing the jacking support device, add soil to the loading box. When adding soil, first pour the soil into the hopper, and open the door below the hopper. During the soil adding process, the left and right movement of the hopper is controlled by controlling the forward and reverse rotation of the motor, and finally the soil is evenly added.

[0056] 4. When the soil is added to the depth of the bottom surface of the existing structure, the existing structure is put in, and the existing structure should be kept horizontal after being put in. After fixing the existing structure, continue to add soil until the soil surface reaches the corresponding position.

[0057] 5. Open the rear door and carry out the tunnel excavation work, divide the tunnel excavation area into four sections, and excavate from inside to outside. After the excavation of each section is completed, the jacking support device at the corresponding position is controlled through the control box to carry out jacking. When the top is about to touch the existing structure, a steel plate is fixed on the top, and then the jacking is continued until the support device touches the bottom surface of the existing structure. A layer of lime is applied under the soil without support of the jacking device to simulate the primary support and prevent the soil from falling and interfering with the experiment.

[0058] 6. Repeat the construction process of stage 5 until the excavation and jacking process of the excavation area is completed.

[0059] 7. After the experiment is completed, the data of the shaft force meter is collected, and the mechanical behavior of the new tunnel closely passing through the existing tunnel is finally obtained.

[0060] It is also important to note that the use of relational terms such as first and second, and the like, are used solely to distinguish one from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0061] The above description is merely the preferred embodiment of the application and is not intended to limit the application. Any modification, equivalent replacement and improvement made without departing from the spirit and principle of the application shall fall within the protection scope of the application.

Claims

1. A device for simulating the active jacking of a tunnel being excavated to pass closely beneath an existing structure, characterised in that, The experimental box is provided with a hopper for adding soil into the experimental box, the hopper is provided with a discharge port at the bottom and can move along the top of the experimental box under the drive of a drive device; a jacking device is fixed in the experimental box, the jacking device is used for applying upward jacking force to the existing structure embedded in the box, the jacking device is connected with a control system for controlling the jacking force and the jacking sequence; a side door for later excavation is arranged on the side of the experimental box; The top of the jacking device is provided with an axial force meter; The top of the jacking device is also provided with a magnetic suction seat connected with a steel plate; The length of the oil pump of the jacking support device is configured to ensure that it protrudes from the bottom surface of the excavated tunnel during the experiment; A plurality of longitudinal and transverse sliding rails are installed in the bottom of the experimental box, and the bottom of the jacking device is provided with sliding blocks matched with the sliding rails; The sliding block is provided with a clamping groove and a moving block, and the side surface of the sliding block is provided with a fastening bolt, the distance between the moving block and the inner side surface of the sliding block is adjusted by adjusting the fastening bolt, and the fixing of the sliding block on the sliding rail is realized; The drive device includes a motor, chain wheels are arranged on the four corners of the top of the experimental box, and a chain wheel is also arranged on one side of the experimental box, the motor drives the hopper to move back and forth on the top of the experimental box through a transmission chain and the chain wheels.

2. The device for driving jacking up of simulating tunneling closely underpassing existing structure according to claim 1, wherein, The jacking device includes a plurality of hydraulic cylinders.

3. The device for driving jacking up of simulating tunneling closely underpassing existing structure according to claim 2, wherein, The plurality of hydraulic cylinders are independently controlled by the control system.

4. The experimental method for simulating the active jacking device for closely passing through the existing structure during tunneling according to any one of claims 1-3, characterized in that, The method includes the following steps: Step 1: determining the direction of tunnel excavation and the position of the jacking support device; Step 2: fixing the jacking device at the position determined in step 1, and requiring that the top end of the jacking support device should be higher than the bottom of the excavated tunnel, connecting the jacking support device to the control box, and connecting the axial force of the jacking support device to the acquisition instrument; Step 3: after fixing the jacking support device, adding soil into the experimental box through the hopper; Step 4: when the soil is added to the depth of the bottom of the existing structure, the existing structure is put in, and the existing structure should be kept horizontal after being put in; after fixing the existing structure, continue to add soil until the soil surface reaches the corresponding position; Step 5: open the side door of the experimental box and perform the excavation work of the tunnel, divide the tunnel excavation area into four sections, and excavate in the order from inside to outside; after the excavation of each section is completed, the jacking support device at the corresponding position is controlled to jacking through the control box; When the top is about to abut against the existing structure, a steel plate is fixed on the top of the jacking support device, and then the jacking is continued until the jacking support device abuts against the bottom surface of the existing structure; a layer of lime is applied under the soil not supported by the jacking device to simulate the initial support and prevent the soil from falling and interfering with the experiment; Step 6: repeat the construction process in step 5 until the excavation and jacking processes of the excavation area are completed; Step 7: after the experiment is completed, the data of the axial force meter is collected, and the mechanical behavior of the new tunnel closely passing through the existing tunnel is finally obtained.

Images