CN106840729B - A test device for simulating segmental excavation of similar rectangular shield - Google Patents

Abstract

The present invention proposes a test device for simulating segmental excavation of a similar rectangular shield machine, which consists of several unit rectangular shield machines connected in sequence, and each unit rectangular shield machine includes a drive control unit, two shrink Mechanism and outer frame; the drive control unit includes four drive motors, and the output end of each drive motor power is connected to a worm gear screw, and its rear end is connected to a live wire; the four drive motors are respectively fixed around each on the support frame. The invention uses a mechanical structure, adopts a rigid mechanical structure and a shell, effectively resists compression and prevents deformation, and makes data more accurate. The use of subsection control is more in line with the data changes in the actual simulation. The invention is simple and convenient, and at the same time, the influence of the quasi-rectangular shield machine on soil loss during operation is considered, and the motor control adopted can also better carry out related indoor model tests.

Description

A test device for simulating segmented excavation of a quasi-rectangular shield

Technical Field

The invention belongs to the technical field of underground engineering, and in particular relates to a test device for simulating segmented excavation of a quasi-rectangular shield.

Background Art

A new shield construction method: the quasi-rectangular shield construction method has been applied in the Ningbo Metro Line 3 project in China. During the construction of the quasi-rectangular shield, the surrounding soil will be deformed, which will inevitably affect the surrounding underground pipelines and buildings. In this regard, it is necessary to conduct in-depth research to help ensure safety during the construction process.

However, there are many uncertainties in field testing during the research process, so most of the indoor scaled-down model tests are used. In view of the needs of the test, a test device that simulates the segmented excavation of a rectangular shield can be more convenient for the test, and the test data obtained can provide effective help for future actual construction.

According to the existing data, there are few scaled-down simulation experiments related to rectangular shield machines. And most soil simulation experiments have the following shortcomings:

(1) Only a single-section TBM model was used for contraction and expansion simulation, and only two-dimensional soil deformation was studied;

(2) Most existing rectangular tunnel boring machines are not precise enough and are rather rough, which has a certain impact on data accuracy; or they are manually operated, which is cumbersome to operate.

Or, for example, the rectangular shield machine simulation excavation experiment conducted by Shanghai Shield Design Experimental Research Center Co., Ltd., which used a test rectangular shield machine with a cross-sectional size of 1200mm×1000mm. The test machine used a cross-shaped structure cutting tool for excavation, two sets of reducers and oil motor drive devices, and a centralized lubrication system was also designed; or, for example, the team led by Ding Wenqi of Tongji University used a quasi-rectangular shield cutting and propulsion simulation test system. Since both of these model test systems are scaled down based on the actual shield machine structure, the biggest drawbacks are:

(3) For large-scale model tests or field experiments, the cost is much higher than the self-made rectangular shield machine model test device of this system.

Summary of the invention

The purpose of the present invention is to overcome the shortcomings of the prior art. The purpose of the present invention is to provide a segmented reduced-size test device for simulating rectangular shield excavation. A 1:20 reduced-size rectangular shield model machine is proposed. Through the segmented design, three-dimensional soil deformation is taken into account. The shield machine is controlled by a motor, which is convenient to operate and saves test time. At the same time, a shrinking model machine with a rigid shell is used to achieve the purpose of simulating soil loss caused by the operation of the shield machine. It can also control soil loss with higher precision and soil deformation that is more consistent with the actual situation, providing more real and accurate experimental data for tunnel construction and design, so as to ensure the efficiency and safety of urban shield tunnel construction.

In order to achieve the above object, the present invention is achieved through the following technical solutions:

The present invention provides a test device for simulating segmented excavation of a quasi-rectangular shield, which comprises a plurality of unit quasi-rectangular shield machines connected in sequence, each unit quasi-rectangular shield machine comprising a drive control unit, two retracting mechanisms and an outer frame;

The drive control unit comprises four drive motors, and the output end of each drive motor power is connected to the worm screw, and the rear end thereof is connected to the power conducting wire;

The four driving motors are fixed around the supporting frames respectively through motor fixing parts;

The outer frame is composed of four quasi-arc-shaped shell pieces connected together, and groove structures are respectively embedded between two adjacent quasi-arc-shaped shell pieces, and a movable gap is maintained between two adjacent arc-shaped pieces; a fender is installed outside the movable gap between two adjacent arc-shaped pieces;

Retracting mechanisms are installed at both ends of the unit-type rectangular shield machine;

The two retracting mechanisms are divided into a lifting mechanism and a horizontal retracting mechanism, among which:

The lifting mechanism includes a turntable, a rotating rod, an arc-shaped lifting block and a supporting frame; the horizontal contraction mechanism includes a gear and a rotating shaft;

The turntable is connected to the support frame through a rotating shaft, and the turntable is connected to the arc-shaped lifting block through a rotating rod. The gear arranged at the drive output end is meshed with the rack on the support frame; the other end of the support frame is fixedly connected to the outer frame;

The control unit is driven to rotate the turntable, drive the rotating rod, rotate the arc-shaped lifting block, and make the upper and lower support frames move vertically, so as to achieve the height change of the rectangular shield machine;

At the same time, the control unit is driven to rotate the gear, driving the rack connected to the support frame, so that the left and right support frames move horizontally, realizing the width change of the rectangular shield machine.

Preferably, two adjacent shield machines are connected via a rubber membrane sleeve.

Compared with the prior art, the present invention has the following beneficial effects:

The first innovative point of the present invention is the use of a mechanical structure, a rigid mechanical structure and a shell, which can effectively resist pressure and prevent deformation, making the data more accurate.

The second innovative point of the present invention is that segmented control is adopted, which is more in line with data changes in actual simulation.

The third innovative point of the present invention is that the device can be completely controlled by a computer or an electronic control terminal, making the operation convenient and stable, and being able to better simulate multiple experiments.

The present invention adopts a motor and a gear to control the rotation contraction amplitude. The rotation contraction is easy to control and stable. The invention can first contract and then expand, and completely simulates the process of soil loss during excavation of a rectangular shield machine.

The present invention adopts a combination of multiple unit-like rectangular shield machines, and can adjust the number of unit-like rectangular shield machines to perform simulations of different lengths in multiple model boxes, and the unit-like rectangular shield machines can be easily combined with each other.

The present invention is simple and convenient, and simultaneously takes into account the influence of the quasi-rectangular shield machine on soil loss during operation. The adopted motor control can also better carry out relevant indoor model tests.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing the area difference of the device of the present invention before and after contraction.

FIG. 2 is a schematic diagram of the side structure of the device of the present invention.

FIG. 3 is a schematic diagram of the three-dimensional structure of the device of the present invention.

FIG. 4 is a schematic diagram of the structure of the device of the present invention before contraction.

FIG. 5 is a schematic diagram of the structure of the device of the present invention after contraction.

Reference numerals: gear (1), driving motor (2), arc-shaped lifting block (3), mudguard (4), outer frame (5), support frame (6), rotating rod (7), rotating disk (8), rotating shaft (9), motor fixing member (10).

DETAILED DESCRIPTION

The technical solution of the present invention is further described below in conjunction with the accompanying drawings:

As shown in Figures 1 to 5, the present invention proposes a specific embodiment of a test device for simulating segmented excavation of a quasi-rectangular shield, which includes a plurality of unit quasi-rectangular shield machines connected in sequence, each unit quasi-rectangular shield machine includes a drive control unit, two retraction mechanisms and an outer frame 5, the drive control unit includes four drive motors 2, and the output end of the power of each drive motor 2 is connected to a worm screw, and the rear end thereof is connected to a powered wire; the four drive motors 2 are respectively fixed around each support frame 6 by a motor fixing member 10; the outer frame 5 is composed of four quasi-arc shell pieces connected, and groove structures are respectively inlaid between two adjacent quasi-arc shell pieces, and a movable gap is maintained between two adjacent arc pieces; a fender 4 is installed on the outside of the movable gap between two adjacent arc pieces; as shown in Figures 4 and 5: in the unit quasi-arc The two ends of the rectangular shield machine are respectively installed with retracting mechanisms, and the two retracting mechanisms are divided into a lifting mechanism and a horizontal retracting mechanism, wherein: the lifting mechanism includes a turntable 8, a rotating rod 7, an arc-shaped lifting block 3 and a support frame 6; the horizontal retracting mechanism includes a gear 1 and a rotating shaft 9; the turntable 8 is connected to the support frame 6 through the rotating shaft 9, and the turntable 8 is connected to the arc-shaped lifting block 3 through the rotating rod 7, and the gear 1 arranged at the drive output end is meshed with the rack on the support frame 6; the other end of the support frame 6 is fixedly connected to the outer frame 5; the turntable 8 is rotated by the driving control unit to drive the rotating rod 7, so that the arc-shaped lifting block 3 is rotated, and the upper and lower support frames 6 are vertically moved to realize the height change of the rectangular shield machine; at the same time, the gear 1 is rotated by the driving control unit to drive the rack connected to the support frame 6, so that the left and right support frames 6 are horizontally moved to realize the width change of the rectangular shield machine.

Among them: two adjacent unit shield machines are connected by a rubber membrane sleeve.

The working process and working principle of the present invention are: installing and placing the model in an experimental soil trough, then filling the soil to simulate the actual soil pressure in a real construction environment, burying the model in the soil, and under the control of the control end, the volume of the model shrinks to simulate the soil loss phenomenon of a rectangular shield machine in excavating a tunnel.

Drive control unit: This model device is driven by multiple motors, with four drive motors in a group. Each unit-like rectangular shield machine has two sets of drive motors and two sets of reducers, and is equipped with a supporting fixture. The rotation of the drive motor causes the lifting mechanism and the horizontal contraction mechanism to move. In order to fix the volume and maintain stability after the drive motor stops moving, the self-locking property of the worm gear is used here, and a worm gear mechanism is installed at the power output of the drive motor. The output of the drive motor is connected to the contraction mechanism, and the rear end is connected to the power wire. Each set of power wires controls a set of drive motors, and multiple sets of power wires are connected to the external control end. The control end can control each set of drive motors separately, and two sets of drive motors control the movement of a unit-like rectangular shield machine, so that the model can achieve segmented control.

As shown in Figures 4 and 5, the contraction mechanism: There are contraction mechanisms at both ends of the quasi-rectangular shield machine, and the contraction mechanism is divided into a lifting mechanism and a horizontal contraction mechanism. Lifting mechanism: The driving control unit rotates the turntable to drive the rotating rod to rotate the arc-shaped lifting block, so that the upper and lower support frames move vertically to change the height of the quasi-rectangular shield machine; Horizontal contraction mechanism: The driving control unit rotates the gear to drive the rack connected to the support frame to move the left and right support frames horizontally to change the width of the quasi-rectangular shield machine. In order to change the area of the circular cross-section and change the volume of the cylinder to achieve the purpose of simulating the land loss caused by the quasi-rectangular shield machine, the lifting mechanism and the horizontal contraction mechanism are driven by the driving motor to move, and the height and width of the model are changed. Due to various factors such as friction and external pressure, the outer frame will hardly rotate significantly clockwise or counterclockwise, and shrink inward under the action of the contraction mechanism. Before and after the contraction, the area of the quasi-rectangular cross-section changes as shown in Figure 1, so that the change in volume is reduced by 5% according to the calculation requirements.

The quasi-rectangular outer frame is composed of four quasi-arc-shaped shell pieces, and the joints thereof use an inlaid structure to prevent sand and soil from entering the seams and causing jamming or inability to shrink, and a mudguard is installed on the outer layer.

The area loss formula in Figure 1 is:

(高与宽为固定比例)

(Height and width are in fixed ratio)

(C为面积损失百分比)

(C is the percentage of area loss)

Where: X is the horizontal width, in mm; Y is the vertical height, in mm; ΔX is the change in horizontal width, in mm; ΔY is the change in vertical height, in mm. In this model, X = 575 mm; Y = 350 mm.

Model segmented connection: A unit-like rectangular shield machine is composed of two sets of drive motors, two sets of retraction mechanisms and an outer frame. Each unit-like rectangular shield machine is connected to the control end respectively, so that the control end can control the retraction of each unit-like rectangular shield machine in a specific order, so as to achieve the purpose of segmented control, make the detected data multi-segmented, and produce a simulation similar to the soil loss during the forward advancement of the rectangular shield machine. A horizontal calibration and support device is installed directly below each unit-like rectangular shield machine, and the unit-like rectangular shield machines are connected with rubber membrane sleeves to prevent each unit-like rectangular shield machine from offset, thereby improving the three-dimensional accuracy.

Through the coordinated operation of the above-mentioned devices, the control end can control the contraction of each unit of the rectangular shield machine in a specific order, so that the soil loss proceeds gradually, realizing a complete simulation of the soil loss in real tunnel construction, and cooperating with other monitoring equipment to digitize the soil changes.

The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention belongs to the protection scope of the present invention.

Claims (3)

1. A test device for simulating segmented excavation of a quasi-rectangular shield, characterized in that it comprises a plurality of unit quasi-rectangular shield machines connected in sequence, each unit quasi-rectangular shield machine comprising a drive control unit, two retraction mechanisms and an outer frame (5), the drive control unit comprising four drive motors (2), and a worm screw for driving the retraction mechanism is connected to the power output end of each drive motor (2), and the rear end of each drive motor (2) is connected to an energized wire; the four drive motors (2) are respectively fixed around each support frame (6) through a motor fixing member (10); The outer frame (5) is composed of four quasi-arc shell pieces connected together, and groove structures are respectively embedded between two adjacent quasi-arc shell pieces, and a movable gap is maintained between two adjacent arc pieces; a contraction mechanism is respectively installed at both ends of the unit quasi-rectangular shield machine, and the two contraction mechanisms are divided into a lifting mechanism and a horizontal contraction mechanism, wherein: the lifting mechanism comprises a turntable (8), a rotating rod (7), an arc-shaped lifting block (3) and a support frame (6); the horizontal contraction mechanism comprises a gear (1) and a rotating shaft (9); the turntable (8) is connected to the support frame (6) through the rotating shaft (9), the turntable (8) is connected to the arc-shaped lifting block (3) through the rotating rod (7), and the gear (1) arranged at the drive output end is meshed with the rack on the support frame (6); the other end of the support frame (6) is fixedly connected to the outer frame (5); the turntable (8) is rotated by the driving control unit to drive the rotating rod (7), so that the arc-shaped lifting block (3) rotates, and the upper and lower support frames (6) move vertically, so as to achieve the height change of the quasi-rectangular shield machine; At the same time, the gear (1) is rotated by the driving control unit to drive the rack connected to the support frame (6), so that the left and right support frames (6) move horizontally, thereby achieving a change in the width of the rectangular shield machine; Each unit-like rectangular shield machine is connected to a control end, and the control end can control the contraction of each unit-like rectangular shield machine in a specific order. 2. A test device for simulating segmented excavation of a quasi-rectangular shield according to claim 1, characterized in that two adjacent unit shield machines are connected by a rubber membrane sleeve. 3. A test device for simulating segmented excavation of a quasi-rectangular shield according to claim 1 or 2, characterized in that a mud guard (4) is installed outside the movable gap between two adjacent arc-shaped pieces.

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