CN114483070A - Model device capable of simulating shield tunnel construction on centrifugal machine - Google Patents

Abstract

The invention discloses a model device capable of simulating shield tunnel construction on a centrifugal machine, which comprises a frame and a model shield machine, wherein a model box is arranged at the front end of the frame, a hole is formed in the rear side wall of the model box, a vertical partition plate is arranged at the rear part of the frame, the model shield machine comprises a shield shell and a model tunnel lining, and a shield cutting, pushing and deslagging system is arranged; the shield cutting motor provides torque, and the cutter head is driven to rotate through the transmission shaft, so that the model shield machine excavates the soil body in the model box; the propelling speed of the model shield tunneling machine is controlled by the shield pushing system, the rotating speeds of the cutter head and the muck conveyor are controlled by the shield cutting system, a soil body to be cut is positioned in the soil bin, and muck is discharged out of the model shield tunneling machine by the muck discharging system. The device aims at guaranteeing that the excavation process of the shield tunnel in the clay can be smoothly simulated under the acceleration condition of the centrifugal machine, is better than a liquid discharge method which is commonly used in the past, and realizes the experimental research of the tunnel excavation centrifugal machine in a more refined clay stratum.

Description

A model device that can simulate shield tunnel construction on a centrifuge

technical field

The invention belongs to the technical field of shield tunnel construction, in particular to a shield tunnel excavation device.

Background technique

With the increasing demand for transportation in today's society, people have shifted the focus to the development and utilization of urban underground space, of which tunnels account for a major proportion. Due to the construction of subway tunnels, underground pipe corridors, etc., the construction environment of subway tunnels is becoming more and more crowded, and single-line tunnels have gradually faded out of people's vision. However, due to the small distance between the tunnels, the mutual influence between the tunnels cannot be ignored, which may cause incalculable surface subsidence, cause damage to ground buildings and structures, and may even face the risk of cracking and collapse. . In addition, most of the subway tunnel construction in Tianjin is carried out in the clay stratum. Clay has the characteristics of high compressibility and low soil strength. Compared with the sandy stratum, it is more likely to cause greater surface subsidence. Therefore, it is necessary to carry out a centrifuge test study on the interaction mechanism of the near tunnel construction, aiming to explore the corresponding surface settlement control measures through the mechanism study. It is necessary to design a set of shield tunnel excavation device, which can not only meet the requirements of excavation in clay, but also ensure the feasibility of the device under the condition of centrifuge acceleration. Nomoto (1999) and others developed a shield excavation centrifuge test suitable for dry sand. This model shield machine can well simulate the excavation process of the shield machine in the dry sand stratum, but in the clay stratum, there are tunnels. The problems of water leakage at the opening and the difficulty of excavating the clay stratum have not yet been resolved. Chapman et al. (2007) developed a small shield machine suitable for clay strata, but the equipment is relatively simple and has a large gap with the real shield machine, and did not consider the improvement of the muck under unfavorable conditions of excavation. While simulating the real shield machine, the action of the device should be simplified as much as possible. For overly complicated devices, such as an earth pressure balance shield model test system developed by Beijing University of Technology (2018), which can realize the monitoring function of cutter head and lining pressure , although it can realize the shield tunneling process and monitor various parameters, but it is not suitable for centrifuge test. Therefore, it is very necessary to design a shield tunnel excavation device that can work normally under the acceleration condition of the centrifuge and simulate the driving process of the real shield machine in the clay layer.

SUMMARY OF THE INVENTION

In view of the prior art, the present invention proposes a model device capable of simulating shield tunnel construction on a centrifuge, which can realize tunnel excavation in clay under the gravitational acceleration of the centrifuge.

In order to solve the above technical problems, the present invention proposes a model device for simulating shield tunnel construction on a centrifuge, including a frame and a model shield machine. There are openings on the side walls, and a vertical partition is arranged at the rear of the frame. The model shield machine includes a shield shell and a model tunnel lining arranged coaxially. The tail of the model tunnel lining is connected to the partition. The plates are connected by bolts; the shield shell and the model tunnel lining are provided with a shield cutting system and a slag tapping system; a shield pushing system is provided at the bottom of the frame; the shield cutting system includes a shield A cutting motor, a transmission shaft and a cutter head, the shield cutting motor is fixed on the partition plate, one end of the transmission shaft is connected with the output end of the shield cutting motor, and the other end of the transmission shaft is connected to the The front end of the model tunnel lining, the cutter head is installed on the other end of the drive shaft; the shield cutting motor provides torque, and the drive shaft drives the cutter head to rotate, so that the model shield machine Excavation of soil in the model box; the shield jacking system includes a shield jacking motor and a jacking screw; the shield jacking motor is installed at the bottom of the rear end of the frame, and the jacking The lead screw is arranged at the bottom of the frame, one end of the jacking lead screw is connected to the output end of the shield jacking motor, and the other end of the jacking lead screw is connected to the rear side wall of the model box, There is a threaded connection between the partition plate and the jacking screw, the output end of the shield jacking motor drives the jacking screw to rotate through a transmission mechanism, and the jacking screw drives the partition plate Move back and forth to realize the excavation of the soil in the model box by the model shield machine; The muck discharge port at the bottom end of the lining tail; the space between the cutter head and the lining of the model tunnel constitutes a soil bin, and the screw conveyor extends into the soil bin, and when the drive shaft rotates, the The soil cut by the cutter head is sent into the screw conveyor and discharged through the muck discharge port.

Further, the model device of the present invention, wherein:

The shield jacking system also includes a guide rail arranged at the bottom of the frame, the guide rail is parallel to the jacking screw, and the guide rail and the jacking screw have the same length; The guide rail is matched with the shaft hole.

Additional openings for fixing the model shield machine are reserved on the partition; when the excavation of a shield tunnel is completed, the model tunnel lining is separated from the partition, and then reserved on the partition Reinstall another model shield machine at another opening of the tunnel to realize the simulation of continuous excavation close to the tunnel.

The selection of the cutter head and cutter assembly is designed according to the type of soil.

For shield tunnel excavation in clay, the cutter assembly includes a leading knife, a cutting knife and a fish tail center knife, the cutter head is a spoke-type cutter head, and the leading knife and the cutting knife are installed on the spokes, The fish tail center knife is installed in the center of the cutter head; the fish tail center knife is installed. For shield tunnel excavation in soft soil layers with good uniformity, the opening rate of the cutter head is 40%-75%.

An earth pressure sensor is arranged on the cutter head to monitor the earth pressure in front of the cutter head; the earth pressure sensor is a wireless sensor.

The shield shell and the model tunnel lining are concentric circles with different cross-sectional sizes, and the diameter of the model tunnel lining is smaller than that of the shield shell.

A sealing ring is arranged at the opening of the rear side wall of the model box, and the inner diameter of the sealing ring is sealed with the outer diameter of the lining of the model tunnel.

Compared with the prior art, the beneficial effects of the present invention are:

(1) This model shield machine can simulate the shield tunneling process of the clay stratum that is difficult to excavate;

(2) The model shield machine is easy to install and disassemble, and is suitable for the simulation of close-to-continuous shield tunneling in clay ground;

(3) The model test device can well solve the soil leakage and water leakage that may occur during the excavation process, and ensure the accuracy of the centrifuge test.

Description of drawings

Fig. 1 is the axial sectional schematic diagram of the model device of the present invention;

Fig. 2 is the structural representation of the cutter head in the model device of the present invention;

In the picture:

1-Cutter 2-Transmission shaft 3-Shield cutting motor 4-Partition

5-jacking screw 6-guide rail 7-shield jacking motor 8-screw conveyor

9- Muck discharge port 10- Model tunnel lining 11- Earth pressure sensor 12- Shield shell

13- Advance Knife 14- Cutting Knife 15- Fishtail Center Knife 16- Opening

17-Model box 18-Sealing ring

Detailed ways

The design concept of the model device that can simulate the construction of shield tunnels on the centrifuge proposed by the present invention is to simulate the shield excavation in the actual soft soil layer, control the propulsion speed of the model shield machine through the shield jacking system, and simultaneously pass The shield cutting system controls the rotation speed of the cutter head and the screw conveyor. The soil to be cut is located in the soil bin, and the slag is discharged out of the model shield machine through the slag discharge system. Centrifuge acceleration can better reflect the response of the surrounding soil, but the soil stress level increases exponentially, which greatly increases the difficulty of shield excavation in the centrifuge. This device is designed to ensure that the centrifuge accelerates. It can successfully simulate the excavation process of shield tunnels in clay, which is better than the commonly used drainage method in the past, and realizes a more refined experimental study of tunnel excavation centrifuges in clay layers.

The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the following embodiments do not limit the present invention by any means.

As shown in FIG. 1 , a model device for simulating shield tunnel construction on a centrifuge proposed by the present invention includes a frame and a model shield machine, and a model box 17 is provided at the front end of the frame. The model box 17 There is an opening 16 on the rear side wall of the frame, and a vertical partition 4 is arranged at the rear of the frame. The model shield machine includes a coaxially arranged shield shell 12 and a model tunnel lining 10. The model tunnel lining The tail of 10 and the partition 4 are connected by bolts; the shield shell 12 and the model tunnel lining 10 are provided with a shield cutting system and a slag extraction system; a shield jacking system is provided at the bottom of the frame .

The shield cutting system includes a shield cutting motor 3, a transmission shaft 2 and a cutter head 2, the shield cutting motor 3 is fixed on the partition plate 4, and one end of the transmission shaft 2 is connected to the shield cutting. The output end of the motor 3 is connected, the other end of the drive shaft 2 is connected to the front end of the model tunnel lining 10, and the cutter head 2 is installed on the other end of the drive shaft 2; the shield cutting motor 3 provides torque , through the drive shaft 2 to drive the cutter head 1 to rotate, so as to realize the excavation of the soil in the model box 17 by the model shield machine;

The shield jacking system includes a shield jacking motor 7 and a jacking screw 5; the shield jacking motor 7 is installed at the bottom of the rear end of the frame, and the jacking screw 5 is arranged on the frame. The bottom of the jacking screw 5 is connected with the output end of the shield jacking motor 7, and the other end of the jacking screw 5 is connected to the rear side wall of the model box 17. There is a threaded connection between the plate 4 and the jacking screw 5. The output end of the shield jacking motor 7 drives the jacking screw 5 to rotate through a transmission mechanism, and the jacking screw 5 drives the jacking screw 5 to rotate. The partition plate 4 moves back and forth to realize the excavation process of the model shield machine in the excavation process of the soil body in the model box 17; the shield jacking system also includes a guide rail 6 arranged at the bottom of the frame, so The guide rail 6 is parallel to the jacking screw 5 , and the guide rail 6 is the same length as the jacking screw 5 ; the baffle 4 and the guide rail 6 are shaft holes matched. The guide rail 6 connected with the baffle 4 is kept parallel to the jacking screw 5, and the jacking screw 5 and the guide rail 6 jointly control the position of the baffle 4 in the process of advancing or retreating, so as to ensure that the model shield machine is not displaced. Precise orientation during excavation.

The slag extraction system includes a screw conveyor 8 fixed on the drive shaft 2 and a slag discharge port 9 arranged at the bottom end of the model tunnel lining 10; The machines 8 are all fixed on the same transmission shaft 2 and controlled by the shield cutting motor 3, so the rotational speed of the two machines is always the same. The space between the cutter head 1 and the model tunnel lining 10 constitutes a soil bin, and the screw conveyor 8 extends into the soil bin. When the drive shaft 2 rotates, the cutter head 1 is cut. The soil is fed into the screw conveyor 8, and discharged from the model shield machine through the muck discharge port 9.

In the present invention, the tail of the model shield machine (namely, the model tunnel lining 10 ) is fixed on the partition plate 4 with bolts, and the partition plate 4 can be reserved with other openings for fixing the model shield machine; the purpose is to When the excavation of a shield tunnel is completed, the model shield machine (the model tunnel lining 10 ) can be separated from the partition plate 4 at the rear, and then another opening reserved on the partition plate 4 can be used. Reinstall another model shield machine to simulate the continuous excavation of the approach tunnel.

The selection of the cutter head 1 and the cutter assembly is designed according to the type of soil. For shield tunnel excavation in clay, the cutter assembly includes a leading knife 13, a cutting knife 14 and a fishtail center knife 15, the cutter head 1 is a spoke-type cutter head, and the leading knife 13 and the cutting knife 14 are installed On the spokes, the fishtail center knife 15 is installed in the center of the cutter head 1 ; the fishtail center knife 15 is installed, as shown in FIG. 2 . For shield tunnel excavation in soft soil strata with good uniformity such as clay, considering the adaptability of cutter head 1 and the stratum, a larger cutter head opening rate should be selected, and the suggested cutter head opening rate is 40%-75% . The larger opening ratio and the selection of the above-mentioned cutters are both beneficial to shield tunnel excavation in clay.

An earth pressure sensor 11 is arranged on the cutter head 1 to monitor the earth pressure in front of the cutter head; the earth pressure sensor 11 selects a wireless sensor to prevent the sensor lead from being damaged due to the rotation of the cutter head (1), thereby causing the earth pressure sensor 11 to fail. .

The shield shell 12 and the model tunnel lining 10 are concentric circles with different cross-sectional sizes, and the diameter of the model tunnel lining 10 is slightly smaller than the diameter of the shield shell 12, which is designed to simulate a shield through a reduced size design. Soil loss in the process of excavation, and this design is more in line with the actual engineering of soil excavation and lining construction alternately.

A sealing ring 18 is provided at the opening 16 of the rear side wall of the model box 17 for sealing. The inner diameter of the sealing ring 18 is sealed with the outer diameter of the model tunnel lining 10 to avoid the reduction of the diameter of the model tunnel lining 10. During the excavation process of the shield machine, the soil in the model box 17 leaks from the opening 16 .

When using the simulation device of the present invention to test, the bottom of the frame of the simulation device shown in FIG. 1 is tightly connected and fixed with the centrifuge basket through bolts, so as to ensure that the device does not fall off during the acceleration of the centrifuge. During the centrifuge test, due to the effect of centrifugal force, the simulation device rotates 90° clockwise (counterclockwise) from the initial vertical state shown in Figure 1, and simultaneously receives the inertial force in the horizontal direction, so as to simulate the stratum of the actual shield tunnel construction. stress level.

The model device of the present invention can realize the simulation of shield tunnel construction on the centrifuge, and the simulation test is as follows:

First, install the model shield machine with bolts on the partition 4, and connect the drive shaft 2 to the shield cutting motor 3. After checking that all components can work normally, start the shield jacking motor 7, and wait until the cutter head 1 is connected to the model. The centrifuge test begins when the soil in tank 17 comes into contact. Start the centrifuge and gradually accelerate to a preset speed to allow the clay to consolidate through drainage to a stress level consistent with the actual formation.

Keep the rotation speed of the centrifuge fixed, and start the shield pushing motor 7 and the shield cutting motor 3 at the same time. The shield jacking motor 7 drives the model shield machine fixed with the partition plate 4 to drive forward at a constant speed through the jacking screw 5, and the shield cutting motor 3 drives the cutter head 1 to rotate and cut the soil body. Enter the soil bin formed between the cutter head 1 and the model tunnel lining 10 , and the model shield machine is discharged by the screw conveyor 8 through the soil discharge port 9 . During the excavation process, the earth pressure sensor 11 on the cutter head 1 and in the soil bin is connected to an external data acquisition device to monitor the earth pressure value in front of the cutter head 1 and in the soil bin in real time. According to the displayed earth pressure value, the shield tunneling speed and the rotation speed of the cutter head 1 are adjusted by the shield jacking motor 7 and the shield cutting motor 3, so as to maintain the earth pressure balance of the model shield machine until the shield tunnel excavation is completed. .

If the continuous excavation model test of the close-to-tunnel is carried out, after the excavation of the first tunnel is completed, the bolts connecting the tail of the model shield machine (model tunnel lining 10) with the partition plate 4 are removed to separate it from the partition plate 4, and the other The tail of a model shield machine is installed at other reserved openings on the partition plate 4, and the above process can be repeated.

Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative rather than restrictive. Under the inspiration of the present invention, many changes can be made without departing from the spirit of the present invention, which all belong to the protection of the present invention.

Claims (9)

1. a model device that can simulate shield tunnel construction on a centrifuge, comprising a frame and a model shield machine, a model box (17) is provided at the front end of the frame, and the rear sidewall of the model box (17) There is an opening (16) on it, which is characterized in that: A vertical partition (4) is provided at the rear of the frame, and the model shield machine includes a shield shell (12) coaxially arranged and a model tunnel lining (10), the tail of the model tunnel lining (10) Bolt connection is adopted between the partition plate (4); the shield shell (12) and the model tunnel lining (10) are provided with a shield cutting system and a slag tapping system; a shield is provided at the bottom of the frame push-up system; The shield cutting system includes a shield cutting motor (3), a transmission shaft (2) and a cutter head (2), the shield cutting motor (3) is fixed on the partition plate (4), and the transmission One end of the shaft (2) is connected with the output end of the shield cutting motor (3), the other end of the transmission shaft (2) is connected to the front end of the model tunnel lining (10), and the cutter head (2) Installed on the other end of the transmission shaft (2); the shield cutting motor (3) provides torque, and drives the cutter head (1) to rotate through the transmission shaft (2) to realize the model shield machine excavation of the soil in the model box (17); The shield jacking system includes a shield jacking motor (7) and a jacking screw (5); the shield jacking motor (7) is installed at the bottom of the rear end of the frame, and the jacking screw (5) is arranged at the bottom of the frame, one end of the jacking screw (5) is connected to the output end of the shield jacking motor (7), and the other end of the jacking screw (5) To the rear side wall of the model box (17), there is a threaded connection between the partition plate (4) and the jacking screw (5), and the output end of the shield jacking motor (7) passes through The transmission mechanism drives the jacking screw (5) to rotate, and the jacking screw (5) drives the partition plate (4) to move back and forth, so that the model shield machine can move the inside of the model box (17). Excavation during the excavation of soil; The slag removal system includes a screw conveyor (8) fixed on the drive shaft (2) and a slag discharge port (9) arranged at the bottom end of the tail of the model tunnel lining (10); the cutter head ( 1) The space between the model tunnel lining (10) constitutes a soil bin, the screw conveyor (8) extends into the soil bin, and while the drive shaft (2) rotates, the cutter head is moved (1) The cut soil is fed into the screw conveyor (8) and discharged through the slag discharge port (9). 2. The model device according to claim 1, wherein the shield jacking system further comprises a guide rail (6) arranged at the bottom of the frame, the guide rail (6) and the jacking screw (5) Parallel, the guide rail (6) and the jacking screw (5) have the same length; the partition plate (4) and the guide rail (6) are shaft holes matched. 3. The model device according to claim 1, characterized in that, additional openings for fixing the model shield machine are reserved on the partition plate (4); when excavation of a shield tunnel is completed, the The model tunnel lining (10) is separated from the partition plate (4), and another model shield machine is re-installed at another opening reserved on the partition plate (4) to realize the continuous excavation of the near tunnel. simulation. 4. The model device according to claim 1, characterized in that, the selection of the cutter head (1) and the cutter assembly is designed according to the type of soil. 5 . The model device according to claim 4 , wherein the cutter assembly comprises a leading cutter ( 13 ), a cutting cutter ( 14 ) and a fish tail center cutter ( 15 ), and the cutter disc ( 1 ) is made of spokes. 6 . Type cutter head, the advance knife (13) and the cutting knife (14) are installed on the spokes, and the fishtail center knife (15) is installed in the center of the cutter head (1); install the fishtail center knife (15). 6 . The model device according to claim 5 , wherein, for shield tunnel excavation in soft soil layers with better uniformity, the opening rate of the cutter head is 40%-75%. 7 . 7. The model device according to claim 1, wherein an earth pressure sensor (11) is provided on the cutter head (1) to monitor the earth pressure in front of the cutter head; the earth pressure sensor (11) is selected from Wireless sensor. 8 . The model device according to claim 1 , wherein the shield shell ( 12 ) and the model tunnel lining ( 10 ) are concentric circles with different cross-sectional sizes, and the model tunnel lining ( 10 ) has The diameter is smaller than the diameter of the shield shell (12). 9 . The model device according to claim 1 , wherein a sealing ring ( 18 ) is provided at the opening ( 16 ) of the rear side wall of the model box ( 17 ), and the inner diameter of the sealing ring ( 18 ) is the same as the diameter of the sealing ring ( 18 ). The outer diameter of the model tunnel lining (10) is sealed.

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