CN118424618A - Test device and test method for determining longitudinal equivalent stiffness of shield tunnel - Google Patents

Abstract

The present invention relates to the field of tunnel engineering technology, and in particular to a test device and a test method for determining the longitudinal equivalent stiffness of a shield tunnel. The test device comprises: a first hinge support and a second hinge support are symmetrically arranged on a test bench, and the first hinge support can be slidably arranged on the test bench; a shield tunnel model is arranged between the first hinge support and the second hinge support, and is connected to the two; a first torque loading assembly is connected to the first hinge support; a second torque loading assembly is connected to the second hinge support; a vertical loading assembly is arranged on the shield tunnel model; one end of the displacement detection assembly is connected to the test bench, and the other end is connected to the shield tunnel model. The test method includes a longitudinal equivalent stiffness test method for the shield tunnel model and a longitudinal equivalent stiffness test method under the action of a target longitudinal axial force. The present invention can complete the longitudinal equivalent bending stiffness test and the longitudinal equivalent shear stiffness test with or without the action of a longitudinal axial force.

Description

Test device and test method for determining the longitudinal equivalent stiffness of shield tunnels

Technical Field

The invention relates to the technical field of tunnel engineering, and in particular to a test device and a test method for determining the longitudinal equivalent stiffness of a shield tunnel.

Background technique

The shield tunnel is a flexible linear assembly structure formed by connecting segments through circumferential and longitudinal bolts. The existence of inter-ring joints greatly weakens the overall longitudinal stiffness of the tunnel structure, making it very easy to deform longitudinally under external static and dynamic disturbances. The longitudinal equivalent continuation model has been widely used in the analysis of longitudinal deformation of shield tunnels due to its clear concept and convenient calculation. This model simplifies the shield tunnel into a one-dimensional homogeneous continuous beam in the longitudinal direction, and reflects the influence of the inter-ring joints of the shield tunnel by reducing the stiffness of the homogeneous continuous beam (i.e., bending stiffness and shear stiffness). Therefore, when using this model to analyze the longitudinal structure of the shield tunnel, the reliability of the longitudinal equivalent stiffness value directly determines the accuracy of the calculation and analysis results of the longitudinal structure of the shield tunnel.

However, the existing longitudinal equivalent continuation models rarely involve the study of the shear stiffness of shield tunnels in the longitudinal direction. In the model test of the longitudinal bending performance of existing shield tunnels, researchers assumed that the longitudinal deformation of the shield tunnel was only contributed by the annular gap opening deformation caused by bending, and generally used three-point bending or four-point bending loading modes for loading, trying to analyze the longitudinal bending performance of the shield tunnel under "pure bending" conditions through the deformation characteristics of the model tunnel. However, it is worth pointing out that due to the existence of the inter-annular joint, the model shield tunnel under this loading mode not only produces annular gap opening deformation, but also annular gap misalignment deformation, that is, at this time, the longitudinal deformation of the shield tunnel is not only related to its bending stiffness, but also depends on its shear stiffness. This makes the actual deformation state of the model tunnel have a large gap with the assumed bending deformation mode, resulting in the "longitudinal equivalent stiffness" of the shield tunnel obtained based on the test results is not accurate.

In addition, due to the construction characteristics of shield tunnels, the thrust force acting on the segment lining during construction causes obvious longitudinal axial force to exist in the shield tunnel over the entire length and for a considerable period of time, and this longitudinal axial force has a significant impact on the longitudinal stiffness characteristics of the shield tunnel. Although some scholars have conducted model test research on the longitudinal equivalent stiffness of shield tunnels under the action of longitudinal axial force, the test principle is basically the same as the situation when there is no longitudinal axial force, that is, the influence of shear deformation caused by segment dislocation is mixed in the bending stiffness analysis. At the same time, there is no model test involving the study of the longitudinal shear stiffness of shield tunnels under the action of longitudinal axial force.

In summary, it is necessary to provide a test device and a test method for determining the longitudinal equivalent stiffness of a shield tunnel, so as to solve the problem that the influence of the longitudinal shear stiffness on the test results of the longitudinal equivalent stiffness of the shield tunnel is not considered in the prior art, and also to solve the problem that the longitudinal shear stiffness of the shield tunnel under the longitudinal axial force cannot be tested in the existing model test equipment.

Summary of the invention

The present invention aims to provide a test device and a test method for determining the longitudinal equivalent stiffness of a shield tunnel. The specific technical scheme is as follows:

In a first aspect, the present invention provides a test device for determining the longitudinal equivalent stiffness of a shield tunnel, comprising a test bench, a first hinge support, a second hinge support, a first torque loading assembly, a second torque loading assembly, a vertical loading assembly, and a displacement detection assembly;

The first hinge support and the second hinge support are symmetrically arranged on the test bench, and the first hinge support can be slidably arranged on the test bench; an installation space is reserved between the first hinge support and the second hinge support; the shield tunnel model is arranged in the installation space, one end of the length direction of the model is connected to the first hinge support, and the other end of the length direction of the model is connected to the second hinge support;

The first torque loading assembly is arranged on the test bench and connected to the first hinge support; the second torque loading assembly is arranged on the test bench and connected to the second hinge support;

The vertical loading assembly is arranged on the radial outer side wall of the shield tunnel model;

The displacement detection assembly comprises a plurality of displacement meters arranged along the length direction of the shield tunnel model, one end of each displacement meter is connected to the test bench, and the other end is connected to the shield tunnel model.

Optionally, the first hinged support includes a first support and a first rotating assembly; the first support can be slidably set on the test bench; the first rotating assembly passes through and is rotatably set on the first support, and is fixedly connected to the shield tunnel model; the first rotating assembly passes through one end of the first support and is detachably connected to the first torque loading assembly.

Optionally, the first rotating assembly includes a first rotating shaft, a first bearing and a first mounting plate; the first rotating shaft passes through the first bearing and is rotatably disposed on the first support; the first mounting plate is fixedly disposed on the first rotating shaft and is fixedly connected to the shield tunnel model; the first rotating shaft passes through one end of the first support and is detachably connected to the first torque loading assembly.

Optionally, the first torque loading assembly includes a first mounting plate, a second mounting plate, a first torque loading member, a second torque loading member and a first lever arm shaft; the first mounting plate and the second mounting plate are arranged on the test bench facing each other; the first lever arm shaft is arranged between the first mounting plate and the second mounting plate; the first torque loading member and the second torque loading member are staggered on both sides of the first lever arm shaft; the fixed end of the first torque loading member is connected to the first mounting plate, and the working end is connected to the first lever arm shaft; the fixed end of the second torque loading member is connected to the second mounting plate, and the working end is connected to the first lever arm shaft; the first lever arm shaft is detachably connected to the first rotating shaft.

Optionally, the second hinged support includes a second support and a second rotating assembly; the second support is fixedly disposed on the test bench; the second rotating assembly passes through and is rotatably disposed on the second support, and is fixedly connected to the shield tunnel model; the second rotating assembly passes through one end of the second support and is detachably connected to the second torque loading assembly.

Optionally, the second rotating assembly includes a second rotating shaft, a second bearing and a second mounting plate; the second rotating shaft passes through the second bearing and is rotatably disposed on the second support; the second mounting plate is fixedly disposed on the second rotating shaft and is fixedly connected to the shield tunnel model; the second rotating shaft passes through one end of the second support and is detachably connected to the second torque loading assembly.

Optionally, the second torque loading assembly includes a third mounting plate, a fourth mounting plate, a third torque loading member, a fourth torque loading member and a second lever arm shaft; the third mounting plate and the fourth mounting plate are arranged on the test bench facing each other; the second lever arm shaft is arranged between the third mounting plate and the fourth mounting plate; the third torque loading member and the fourth torque loading member are staggered on both sides of the second lever arm shaft; the fixed end of the third torque loading member is connected to the third mounting plate, and the working end is connected to the second lever arm shaft; the fixed end of the fourth torque loading member is connected to the fourth mounting plate, and the working end is connected to the second lever arm shaft; the second lever arm shaft is detachably connected to the second rotating shaft.

Optionally, the vertical loading assembly includes a loading pad and a gravity piece; the loading pad is arranged on the radial outer wall of the shield tunnel model, and a contoured arc groove adapted to the radial outer wall of the shield tunnel model is arranged on the loading pad; the gravity piece is arranged on the loading pad.

Optionally, the test device also includes a longitudinal axial force loading assembly arranged along the length direction of the shield tunnel model; the longitudinal axial force loading assembly includes an axial force adjustment screw and a pressure sensor; one end of the axial force adjustment screw is a connecting end, and is threadedly connected to the test bench, and the other end is an axial force adjustment end, and is arranged close to or away from the first hinge support; the pressure sensor is arranged on the axial force adjustment end of the axial force adjustment screw.

In a second aspect, the present invention provides a test method for the test device, including a longitudinal equivalent stiffness test method for the shield tunnel model and a longitudinal equivalent stiffness test method under a target longitudinal axial force:

The longitudinal equivalent stiffness test method for the shield tunnel model includes:

Step S1, installing the shield tunnel model on the test device, removing the vertical loading assembly, and moving the longitudinal axial force loading assembly away from the first hinge support, so that the shield tunnel model is in a hinged support constraint state under the action of the first hinge support and the second hinge support;

Step S2, synchronously driving the first torque loading component and the second torque loading component with the same torque so that the first hinge support and the second hinge support synchronously link the two ends of the shield tunnel model, so that the shield tunnel model generates longitudinal pure bending deformation in the length direction; using the displacement meter to measure the data of the longitudinal pure bending deformation of the shield tunnel model;

The longitudinal equivalent bending stiffness of the shield tunnel model is determined by formula (1);

(1);

in, It represents the longitudinal equivalent bending stiffness of the shield tunnel model; represents the torque applied to the end of the shield tunnel model; Indicates the length of the shield tunnel model; Indicates the position of displacement deformation measurement points along the length direction of the shield tunnel model; It represents the longitudinal deformation of the shield tunnel model at different displacement deformation measuring points measured by the displacement meter under the condition of longitudinal pure bending deformation;

Step S3, synchronously unloading the torque of the first torque loading assembly and the second torque loading assembly, and disconnecting the connection between the first torque loading assembly and the first hinge support and the connection between the second torque loading assembly and the second hinge support, so that the shield tunnel model is in the hinged support constraint state in step S1;

The vertical loading assembly is installed on the radial outer side wall of the shield tunnel model, and the first hinge support and the second hinge support are used to provide support points for both ends of the shield tunnel model, so as to achieve three-point bending loading of the shield tunnel model to generate longitudinal bending and shear deformation; the displacement meter is used to measure the longitudinal deformation data generated by the shield tunnel model under the vertical loading state;

According to Timoshenko beam theory, using equations (2)-(3) and combining equation (1) to obtain Determining the longitudinal equivalent shear stiffness of the shield tunnel model;

(2);

(3);

in, is the longitudinal equivalent shear stiffness of the shield tunnel model; It is the concentrated load applied on the shield tunnel model by the vertical loading component; It represents the longitudinal deformation of the shield tunnel model contributed only by the bending action under the longitudinal three-point bending loading condition; It represents the longitudinal deformation of the shield tunnel model at different displacement deformation measuring points measured by the displacement meter under three-point bending loading conditions;

The longitudinal equivalent stiffness test method of the shield tunnel model under the target longitudinal axial force includes:

The axial force adjusting screw is used to approach and push the first hinge support to link the shield tunnel model in the hinge support constraint state in step S1. When the axial force adjusting screw is adjusted so that the reading displayed by the pressure sensor reaches the target longitudinal axial force applied to the shield tunnel model, the adjustment of the axial force adjusting screw is stopped and the target longitudinal axial force is maintained; according to steps S2-S3, the longitudinal equivalent stiffness test of the shield tunnel model under the target longitudinal axial force is implemented.

The application of the technical solution of the present invention has at least the following beneficial effects:

The present invention provides a test device and a test method for determining the longitudinal equivalent stiffness of a shield tunnel. The first torque loading component and the second torque loading component are synchronously driven so that the first hinge support and the second hinge support synchronously link the two ends of the shield tunnel model, so that the shield tunnel model generates longitudinal pure bending deformation in the length direction; the displacement meter is used to measure the data of the longitudinal pure bending deformation generated by the shield tunnel model; the longitudinal equivalent bending stiffness of the shield tunnel model is determined by formula (1); the vertical loading component is installed on the radial outer wall of the shield tunnel model, and the first hinge support and the second hinge support are used to provide support points for the two ends of the shield tunnel model, so as to realize three-point bending loading on the shield tunnel model to generate longitudinal bending shear deformation; the displacement meter is used to measure the data of the longitudinal shear deformation generated by the shield tunnel model; the longitudinal equivalent shear stiffness of the shield tunnel model is determined by (EI)eq obtained by formula (2)-formula (3) and formula (1). Therefore, the present invention not only completes the longitudinal equivalent bending stiffness test, but also completes the longitudinal equivalent shear stiffness test, which can solve the problem that the prior art does not consider the influence of the longitudinal shear stiffness on the longitudinal equivalent stiffness test results of the shield tunnel. In addition, the present invention also uses the axial force adjustment screw and the pressure sensor to implement the longitudinal equivalent stiffness test of the shield tunnel model under the target longitudinal axial force, which solves the problem that the existing model test equipment cannot test the longitudinal shear stiffness of the shield tunnel under the longitudinal axial force.

In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

FIG1 is a schematic diagram of the structure of a test device for determining the longitudinal equivalent stiffness of a shield tunnel in an embodiment of the present invention;

FIG2 is a schematic structural diagram of the combined installation of the first hinge support and the longitudinal axial force loading assembly in FIG1 ;

FIG3 is a schematic structural diagram of the second torque loading assembly in FIG1 ;

FIG4 is a schematic diagram showing the principle of performing a longitudinal equivalent bending stiffness test on a shield tunnel model in step S2 (the arrow direction of Me in the figure indicates the torque direction);

FIG5 is a schematic diagram showing the principle of performing a longitudinal equivalent shear stiffness test on a shield tunnel model in step S3 (the arrow direction of P in the figure indicates the vertical loading direction);

Among them, 1. test bench, 2. first hinge support, 2.1. first support, 2.2. first base, 2.3. first rotating shaft, 2.4. first bearing, 2.5. first mounting plate, 3. second hinge support, 4. first torque loading assembly, 5. second torque loading assembly, 5.1. third mounting plate, 5.2. fourth mounting plate, 5.3. third torque loading member, 5.4. fourth torque loading member, 5.5. second lever arm shaft, 6. vertical loading assembly, 6.1. loading pad, 6.2. gravity member, 7. displacement detection assembly, 7.1. displacement meter, 8. longitudinal axial force loading assembly, 8.1. axial force adjustment screw, 8.2. pressure sensor, A. shield tunnel model.

Detailed ways

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

Embodiment:

Referring to FIGS. 1 to 5 , a test device for determining the longitudinal equivalent stiffness of a shield tunnel includes a test bench 1, a first hinge support 2, a second hinge support 3, a first torque loading assembly 4, a second torque loading assembly 5, a vertical loading assembly 6, and a displacement detection assembly 7;

The first hinge support 2 and the second hinge support 3 are symmetrically arranged on the test bench 1, and the first hinge support 2 can be slidably arranged on the test bench 1, so as to provide a deformable space for the shield tunnel model A when it generates longitudinal pure bending deformation and longitudinal bending and shear deformation; an installation space is reserved between the first hinge support 2 and the second hinge support 3; the shield tunnel model A (a multi-ring segment assembly structure, specifically modeled after a prototype shield tunnel in a certain place and scaled at a ratio of 1:20) is arranged in the installation space, one end of which in the length direction is connected to the first hinge support 2, and the other end of which in the length direction is connected to the second hinge support 3;

The first torque loading component 4 is arranged on the test bench 1 and connected to the first hinge support 2; the second torque loading component 5 is arranged on the test bench 1 and connected to the second hinge support 3; when the first torque loading component 4 and the second torque loading component 5 are synchronously applied with torque, the first hinge support 2 and the second hinge support 3 can synchronously link the two ends of the shield tunnel model A, so that the shield tunnel model A generates longitudinal pure bending deformation in the length direction;

The vertical loading component 6 is arranged on the radial outer side wall of the shield tunnel model A. Specifically, the vertical loading component 6 can be selectively arranged on the radial outer side wall of the shield tunnel model A at the midpoint in the length direction, so as to apply a mid-span concentrated load to the shield tunnel model A;

The displacement detection component 7 includes a plurality of displacement meters 7.1 evenly arranged along the length direction of the shield tunnel model A, one end of each displacement meter 7.1 is connected to the test bench 1, and the other end is connected to the shield tunnel model A; the use of a plurality of displacement meters 7.1 facilitates comprehensive detection of the displacement changes of the shield tunnel model A along the longitudinal direction.

Referring to Figures 1 and 2, the first hinge support 2 includes a first support 2.1 and a first rotating assembly; the first support 2.1 is specifically two, and is symmetrically and slidably arranged on the test bench 1; specifically, the first hinge support 2 also includes a first base 2.2 fixedly arranged on the test bench 1, a guide rail is arranged on the first base 2.2, and a slide groove adapted to the guide rail is arranged on the first support 2.1, thereby realizing the sliding setting of the first support 2.1; the first rotating assembly passes through and is rotatably arranged on the first support 2.1, and is fixedly connected to the shield tunnel model A; the first rotating assembly passes through one end of the first support 2.1 and is detachably connected to the first torque loading assembly 4.

Referring to Figures 1 and 2, the first rotating assembly includes a first rotating shaft 2.3 (specifically a steel rotating shaft), a first bearing 2.4 and a first mounting plate 2.5; the first rotating shaft 2.3 passes through the first bearing 2.4 and is rotatably arranged on the first support 2.1; the first mounting plate 2.5 is fixedly arranged on the first rotating shaft 2.3 and is fixedly connected to the shield tunnel model A; one end of the first rotating shaft 2.3 passes through the first support 2.1 and is detachably connected to the first torque loading assembly 4.

The first torque loading assembly 4 includes a first mounting plate, a second mounting plate, a first torque loading member (specifically a hydraulic jack), a second torque loading member (specifically a hydraulic jack) and a first lever shaft; the first mounting plate and the second mounting plate are arranged on the test bench 1 facing each other; the first lever shaft is arranged between the first mounting plate and the second mounting plate; the first torque loading member and the second torque loading member are staggered on both sides of the first lever shaft; the fixed end of the first torque loading member is connected to the first mounting plate, and the working end is connected to the first lever shaft; specifically, a mounting groove adapted to the working end of the first torque loading member is provided on the first lever shaft, so as to facilitate the rapid installation of the working end of the first torque loading member; the fixed end of the second torque loading member is connected to the second mounting plate, and the working end is connected to the first lever shaft; specifically, a mounting groove adapted to the working end of the second torque loading member is provided on the first lever shaft, so as to facilitate the rapid installation of the working end of the second torque loading member; the first lever shaft and the first rotating shaft 2.3 are detachably connected through a first three-way steel sleeve.

The second hinged support 3 includes a second support and a second rotating assembly; the second support is specifically two and is symmetrically fixed on the test bench 1; the second rotating assembly passes through and is rotatably arranged on the second support and is fixedly connected to the shield tunnel model A; the second rotating assembly passes through one end of the second support and is detachably connected to the second torque loading assembly 5.

The second rotating assembly includes a second rotating shaft (specifically a steel rotating shaft), a second bearing and a second mounting plate; the second rotating shaft passes through the second bearing and is rotatably arranged on the second support; the second mounting plate is fixedly arranged on the second rotating shaft and is fixedly connected to the shield tunnel model A; the second rotating shaft passes through one end of the second support and is detachably connected to the second torque loading assembly 5.

Referring to Fig. 1 and Fig. 3, the second torque loading assembly 5 comprises a third mounting plate 5.1, a fourth mounting plate 5.2, a third torque loading member 5.3 (specifically a hydraulic jack), a fourth torque loading member 5.4 (specifically a hydraulic jack) and a second lever shaft 5.5; the third mounting plate 5.1 and the fourth mounting plate 5.2 are arranged on the test bench 1 facing each other; the second lever shaft 5.5 is arranged between the third mounting plate 5.1 and the fourth mounting plate 5.2; the third torque loading member 5.3 and the fourth torque loading member 5.4 are arranged on both sides of the second lever shaft 5.5 in an offset manner; the fixed end of the third torque loading member 5.3 is connected to the third mounting plate 5. 1, and the working end is connected to the second lever arm shaft 5.5; specifically, the second lever arm shaft 5.5 is provided with a mounting groove adapted to the working end of the third torque loading member 5.3, so as to facilitate the rapid installation of the working end of the third torque loading member 5.3; the fixed end of the fourth torque loading member 5.4 is connected to the fourth mounting plate 5.2, and the working end is connected to the second lever arm shaft 5.5; specifically, the second lever arm shaft 5.5 is provided with a mounting groove adapted to the working end of the fourth torque loading member 5.4, so as to facilitate the rapid installation of the working end of the fourth torque loading member 5.4; the second lever arm shaft 5.5 and the second rotating shaft are detachably connected through a second three-way steel sleeve.

Referring to Figure 1, the vertical loading assembly 6 includes a loading pad 6.1 and a gravity member 6.2 (specifically, weights, the number of weights is determined according to test requirements); the loading pad 6.1 is arranged on the radial outer wall of the shield tunnel model A, and a contoured arc groove adapted to the radial outer wall of the shield tunnel model A is arranged on the loading pad 6.1; the gravity member 6.2 is arranged on the loading pad 6.1.

Referring to Figures 1 and 2, the test device also includes a longitudinal axial force loading component 8 arranged along the length direction of the shield tunnel model A; the longitudinal axial force loading component 8 includes an axial force adjustment screw 8.1 and a pressure sensor 8.2; one end of the axial force adjustment screw 8.1 is a connecting end, and is threadedly connected to the first base 2.2 set on the test bench 1, and the other end is an axial force adjustment end, and is set close to or away from the first hinge support 2; the pressure sensor 8.2 is set on the axial force adjustment end of the axial force adjustment screw 8.1.

The test method of the test device includes a longitudinal equivalent stiffness test method for the shield tunnel model A and a longitudinal equivalent stiffness test method under the target longitudinal axial force:

The longitudinal equivalent stiffness test method for the shield tunnel model A (i.e. the longitudinal equivalent stiffness test method without longitudinal axial force) includes:

Step S1, installing the shield tunnel model A on the test device, removing the vertical loading assembly 6, and moving the longitudinal axial force loading assembly 8 away from the first hinge support 2, so that the shield tunnel model A is in a hinged support constraint state under the action of the first hinge support 2 and the second hinge support 3;

Step S2, referring to FIG. 4, the first torque loading component 4 and the second torque loading component 5 are synchronously driven with the same torque so that the first hinge support 2 and the second hinge support 3 synchronously link the two ends of the shield tunnel model A, so that the shield tunnel model A generates longitudinal pure bending deformation in the length direction; the displacement meter 7.1 is used to measure the data of the longitudinal pure bending deformation of the shield tunnel model A;

The longitudinal equivalent bending stiffness of the shield tunnel model A is determined by using the Timoshenko beam theory shown in formula (1);

(1);

in, represents the longitudinal equivalent bending stiffness of shield tunnel model A; represents the torque applied to the end A of the shield tunnel model; represents the length of shield tunnel model A; Indicates the position of the displacement deformation measuring point along the length direction of shield tunnel model A; It represents the longitudinal deformation of the shield tunnel model A at different displacement deformation measuring points measured by the displacement meter 7.1 under the condition of longitudinal pure bending deformation;

Step S3, synchronously unloading the torque of the first torque loading component 4 and the second torque loading component 5, and disconnecting the connection between the first torque loading component 4 and the first hinge support 2 and the connection between the second torque loading component 5 and the second hinge support 3, so that the shield tunnel model A is in the hinged support constraint state in step S1;

Referring to FIG. 5 , the vertical loading assembly 6 is installed on the radial outer side wall of the shield tunnel model A, and the first hinge support 2 and the second hinge support 3 are used to provide support points for both ends of the shield tunnel model A, so as to achieve three-point bending loading of the shield tunnel model A to generate longitudinal bending and shear deformation; the displacement meter 7.1 is used to measure the longitudinal bending and shear deformation data generated by the shield tunnel model A under the vertical loading condition;

According to Timoshenko beam theory, using equations (2)-(3) and combining equation (1) to obtain Determining the longitudinal equivalent shear stiffness of the shield tunnel model A;

(2);

(3);

in, is the longitudinal equivalent shear stiffness of shield tunnel model A; is the concentrated load applied by the vertical loading component 6 on the shield tunnel model A; It represents the longitudinal deformation of shield tunnel model A contributed only by bending action under three-point bending loading condition; represents the longitudinal deformation of the shield tunnel model A at different displacement deformation measuring points measured by the displacement meter 7.1 under the three-point bending loading condition;

The longitudinal equivalent stiffness test method of the shield tunnel model A under the target longitudinal axial force includes:

The axial force adjusting screw 8.1 is used to approach and push the first hinge support 2 to link the shield tunnel model A in the hinge support constraint state in step S1, and the axial force adjusting screw 8.1 is adjusted so that when the reading displayed by the pressure sensor 8.2 reaches the target longitudinal axial force applied to the shield tunnel model A, the adjustment of the axial force adjusting screw 8.1 is stopped and the target longitudinal axial force is maintained; according to steps S2-S3, the longitudinal equivalent stiffness test of the shield tunnel model A under the target longitudinal axial force is implemented.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. A test device for determining the longitudinal equivalent stiffness of a shield tunnel, characterized in that it comprises a test bench (1), a first hinge support (2), a second hinge support (3), a first torque loading component (4), a second torque loading component (5), a vertical loading component (6) and a displacement detection component (7); The first hinge support (2) and the second hinge support (3) are symmetrically arranged on the test bench (1), and the first hinge support (2) can be slidably arranged on the test bench (1); an installation space is reserved between the first hinge support (2) and the second hinge support (3); a shield tunnel model (A) is arranged in the installation space, one end of which is connected to the first hinge support (2) in the length direction, and the other end of which is connected to the second hinge support (3) in the length direction; The first torque loading assembly (4) is arranged on the test bench (1) and connected to the first hinge support (2); the second torque loading assembly (5) is arranged on the test bench (1) and connected to the second hinge support (3); The vertical loading assembly (6) is arranged on the radial outer side wall of the shield tunnel model (A); The displacement detection assembly (7) comprises a plurality of displacement meters (7.1) arranged along the length direction of the shield tunnel model (A), one end of each displacement meter (7.1) being connected to the test bench (1) and the other end being connected to the shield tunnel model (A). 2. The test device according to claim 1 is characterized in that the first hinge support (2) comprises a first support (2.1) and a first rotating assembly; the first support (2.1) is slidably arranged on the test bench (1); the first rotating assembly passes through and is rotatably arranged on the first support (2.1) and is fixedly connected to the shield tunnel model (A); the first rotating assembly passes through one end of the first support (2.1) and is detachably connected to the first torque loading assembly (4). 3. The test device according to claim 2 is characterized in that the first rotating assembly comprises a first rotating shaft (2.3), a first bearing (2.4) and a first mounting plate (2.5); the first rotating shaft (2.3) passes through the first bearing (2.4) and is rotatably arranged on the first support (2.1); the first mounting plate (2.5) is fixedly arranged on the first rotating shaft (2.3) and is fixedly connected to the shield tunnel model (A); one end of the first rotating shaft (2.3) passing through the first support (2.1) is detachably connected to the first torque loading assembly (4). 4. The test device according to claim 3 is characterized in that the first torque loading assembly (4) includes a first mounting plate, a second mounting plate, a first torque loading member, a second torque loading member and a first lever arm shaft; the first mounting plate and the second mounting plate are arranged on the test bench (1) facing each other; the first lever arm shaft is arranged between the first mounting plate and the second mounting plate; the first torque loading member and the second torque loading member are staggered on both sides of the first lever arm shaft; the fixed end of the first torque loading member is connected to the first mounting plate, and the working end is connected to the first lever arm shaft; the fixed end of the second torque loading member is connected to the second mounting plate, and the working end is connected to the first lever arm shaft; the first lever arm shaft is detachably connected to the first rotating shaft (2.3). 5. The test device according to claim 1 is characterized in that the second hinge support (3) includes a second support and a second rotating assembly; the second support is fixedly arranged on the test bench (1); the second rotating assembly passes through and is rotatably arranged on the second support, and is fixedly connected to the shield tunnel model (A); the second rotating assembly passes through one end of the second support and is detachably connected to the second torque loading assembly (5). 6. The test device according to claim 5 is characterized in that the second rotating assembly includes a second rotating shaft, a second bearing and a second mounting plate; the second rotating shaft passes through the second bearing and is rotatably arranged on the second support; the second mounting plate is fixedly arranged on the second rotating shaft and is fixedly connected to the shield tunnel model (A); the second rotating shaft passes through one end of the second support and is detachably connected to the second torque loading assembly (5). 7. The test device according to claim 6 is characterized in that the second torque loading assembly (5) comprises a third mounting plate (5.1), a fourth mounting plate (5.2), a third torque loading member (5.3), a fourth torque loading member (5.4) and a second lever shaft (5.5); the third mounting plate (5.1) and the fourth mounting plate (5.2) are arranged on the test bench (1) facing each other; the second lever shaft (5.5) is arranged between the third mounting plate (5.1) and the fourth mounting plate (5.2); The third torque loading member (5.3) and the fourth torque loading member (5.4) are staggeredly arranged on both sides of the second lever arm shaft (5.5); the fixed end of the third torque loading member (5.3) is connected to the third mounting plate (5.1), while the operating end is connected to the second lever arm shaft (5.5); the fixed end of the fourth torque loading member (5.4) is connected to the fourth mounting plate (5.2), while the operating end is connected to the second lever arm shaft (5.5); the second lever arm shaft (5.5) is detachably connected to the second rotating shaft. 8. The test device according to claim 7 is characterized in that the vertical loading assembly (6) comprises a loading pad (6.1) and a gravity member (6.2); the loading pad (6.1) is arranged on the radial outer side wall of the shield tunnel model (A), and a contoured arc groove adapted to the radial outer side wall of the shield tunnel model (A) is arranged on the loading pad (6.1); the gravity member (6.2) is arranged on the loading pad (6.1). 9. The test device according to any one of claims 1 to 8 is characterized in that it also includes a longitudinal axial force loading component (8) arranged along the length direction of the shield tunnel model (A); the longitudinal axial force loading component (8) includes an axial force adjustment screw (8.1) and a pressure sensor (8.2); one end of the axial force adjustment screw (8.1) is a connecting end, and is threadedly connected to the test bench (1), and the other end is an axial force adjustment end, and is arranged close to or away from the first hinge support (2); the pressure sensor (8.2) is arranged on the axial force adjustment end of the axial force adjustment screw (8.1). 10. A test method for the test device according to claim 9, characterized in that it comprises a longitudinal equivalent stiffness test method for the shield tunnel model (A) and a longitudinal equivalent stiffness test method under a target longitudinal axial force: The longitudinal equivalent stiffness test method for the shield tunnel model (A) includes: Step S1, installing the shield tunnel model (A) on the test device, removing the vertical loading component (6), and moving the longitudinal axial force loading component (8) away from the first hinge support (2), so that the shield tunnel model (A) is in a hinged support constraint state under the action of the first hinge support (2) and the second hinge support (3); Step S2, synchronously driving the first torque loading component (4) and the second torque loading component (5) with the same torque so that the first hinge support (2) and the second hinge support (3) synchronously link the two ends of the shield tunnel model (A), so that the shield tunnel model (A) generates longitudinal pure bending deformation in the length direction; using the displacement meter (7.1) to measure the data of the longitudinal pure bending deformation generated by the shield tunnel model (A); The longitudinal equivalent bending stiffness of the shield tunnel model (A) is determined by formula (1); (1); in, represents the longitudinal equivalent bending stiffness of the shield tunnel model (A); represents the torque applied to the end of the shield tunnel model (A); represents the length of the shield tunnel model (A); Indicates the position of displacement deformation measurement points along the length direction of the shield tunnel model (A); represents the longitudinal deformation of the shield tunnel model (A) at different displacement deformation measuring points measured by the displacement meter (7.1) under the condition of longitudinal pure bending deformation; Step S3, synchronously unloading the torque of the first torque loading component (4) and the second torque loading component (5), and disconnecting the connection between the first torque loading component (4) and the first hinge support (2) and the connection between the second torque loading component (5) and the second hinge support (3), so that the shield tunnel model (A) is in the hinged support constraint state in step S1; The vertical loading assembly (6) is installed on the radial outer side wall of the shield tunnel model (A), and the first hinge support (2) and the second hinge support (3) are used to provide support points for both ends of the shield tunnel model (A), so as to achieve three-point bending loading of the shield tunnel model (A) to generate longitudinal bending and shear deformation; the displacement meter (7.1) is used to measure the longitudinal deformation data generated by the shield tunnel model (A) under the vertical loading state; According to Timoshenko beam theory, using equations (2)-(3) and combining equation (1) to obtain Determining the longitudinal equivalent shear stiffness of the shield tunnel model (A); (2); (3); in, is the longitudinal equivalent shear stiffness of the shield tunnel model (A); is the concentrated load applied by the vertical loading component (6) on the shield tunnel model (A); (A) Longitudinal deformation of the shield tunnel model under three-point bending loading condition contributed only by bending action; represents the longitudinal deformation of the shield tunnel model (A) at different displacement deformation measuring points measured by the displacement meter (7.1) under three-point bending loading conditions; The longitudinal equivalent stiffness test method of the shield tunnel model (A) under the target longitudinal axial force comprises: The axial force adjustment screw (8.1) is used to approach and push the first hinge support (2) to link the shield tunnel model (A) in the hinge support constraint state in step S1, and the axial force adjustment screw (8.1) is adjusted so that when the reading displayed by the pressure sensor (8.2) reaches the target longitudinal axial force applied to the shield tunnel model (A), the adjustment of the axial force adjustment bolt (8.1) is stopped and the target longitudinal axial force is maintained; according to steps S2-S3, a longitudinal equivalent stiffness test of the shield tunnel model (A) under the target longitudinal axial force is implemented.