A stress deformation model test device and method for a diaphragm wall with a slotted segment joint

Abstract

The application provides a stress deformation model test device and method of a cutoff wall containing a groove segment joint in the technical field of geotechnical engineering. The device comprises a self-counterforce frame, a horizontal lateral actuator, a horizontal axial actuator, a vertical actuator, a dial gauge and a cutoff wall model. The self-counterforce frame is used for bearing the cutoff wall model and providing counterforce support. The cutoff wall model is formed by pouring a plurality of groove segments in sequence, and groove segment joints are formed between adjacent groove segments, which are used for simulating the structure of the cutoff wall and bearing loads. The horizontal lateral actuator is used for applying a horizontal load to the cutoff wall model. The horizontal axial actuator is used for applying an axial load to the cutoff wall model. The vertical actuator is used for applying a vertical load to the cutoff wall model. The dial gauge is used for measuring the horizontal displacement of the cutoff wall model at different positions. The application can simulate the multi-directional stress state of the cutoff wall containing the groove segment joint under controlled conditions, and provides a reliable test method for the design optimization, safety evaluation and seismic performance research of the cutoff wall.

Description

Technical Field

[0001] This invention relates to a test apparatus and method for a seepage barrier wall with grooved joints under stress and deformation, belonging to the field of geotechnical engineering technology. Background Technology

[0002] In earth-rock dam engineering, cutoff walls are generally used for seepage control on dam foundations with deep overburden layers. The construction of cutoff walls requires segmented construction. When constructing the second-stage wall, the presence of retaining mud makes it difficult to achieve a seamless connection with the first-stage wall, potentially creating a joint with mud cake between the two stages. This joint is a weak point in the cutoff wall; under stress, tension and torsion may occur at the joint, significantly reducing the wall's overall integrity. However, traditional calculations and analyses of earth-rock dams generally treat the cutoff wall as a single unit, which obviously fails to reflect its true stress and deformation characteristics and overestimates its tensile and compressive stresses. Therefore, it is necessary to conduct a systematic study on the stress and deformation patterns of cutoff walls containing joints, revealing their mechanical properties, influencing factors, and variation patterns, providing a basis for accurate analysis and evaluation of the stress and deformation characteristics of cutoff walls. However, current research on the stress and deformation of cutoff walls containing joints is scarce, and specialized experimental equipment and methods are still lacking. Summary of the Invention

[0003] The purpose of this invention is to provide a test device and method for the stress and deformation model of a cutoff wall with grooved joints. Through this device and method, stress and deformation test studies of cutoff walls with grooved joints can be carried out systematically to obtain the operational characteristics of cutoff walls that conform to engineering practice, and to provide a reference for the design of cutoff walls for earth-rock dams.

[0004] To achieve the above objectives, the present invention is implemented using the following technical solution: In the first aspect, the present invention proposes a test device for a seepage barrier wall stress deformation model with groove joint, comprising a self-reaction frame, a horizontal lateral actuator, a horizontal axial actuator, a vertical actuator, a column, a dial gauge, and a seepage barrier wall model. The self-reactive frame is used to support the impermeable wall model and provide reaction force support; The first end of the anti-seepage wall model is connected to the first end of the horizontal axial actuator, and the second end is connected to the self-reaction frame, which is used to simulate the anti-seepage wall structure and bear the load. The column is fixedly connected to the self-reactive frame; The first end of the horizontal lateral actuator is fixedly connected to the column, and the second end is connected to the anti-seepage wall model, for applying a horizontal load to the anti-seepage wall model; The second end of the horizontal axial actuator is fixedly connected to the self-reactive frame and is used to apply axial load to the seepage barrier model. The first end of the vertical actuator is fixedly connected to the self-reactive force frame, and the second end is connected to the anti-seepage wall model, which is used to apply vertical load to the anti-seepage wall model; The dial gauge is connected to the test model of the seepage barrier wall and is used to measure the horizontal displacement at different positions of the seepage barrier wall model.

[0005] Furthermore, the self-reactive frame is a cube, comprising 4 corner posts, 2 long beams and 2 short beams located at the top, and 2 long beams and 2 short beams located at the bottom.

[0006] Furthermore, the second end of the anti-seepage wall model is closely attached to a corner column of the self-reaction frame, and the bottom of both ends is supported by end pads on the long beam at the bottom of the self-reaction frame, with the middle part suspended in the air.

[0007] Furthermore, the impermeable wall model is formed by casting several sections in sequence, with joints formed between adjacent sections.

[0008] Furthermore, the horizontal lateral actuators are arranged in a matrix, with each horizontal lateral actuator in the same horizontal row located on the same horizontal line, and each horizontal lateral actuator in the same vertical row located on the same vertical line; the number of horizontal lateral actuators in each horizontal row is equal to the number of trench segments in the anti-seepage wall model.

[0009] Furthermore, the dial gauge is fixed to the dial gauge mounting bracket, and the probe of the dial gauge is in contact with the anti-seepage wall model. The dial gauges are arranged in several rows from top to bottom, and the number of dial gauges in each row is twice the number of the trench joints. One dial gauge is set on each of the left and right sides of each trench joint.

[0010] Furthermore, it also includes end supports, which are square steel rods vertically inserted into the pre-drilled holes of the self-reaction frame to block the horizontal displacement at both ends of the seepage barrier model, and the end supports can be pulled out vertically.

[0011] Furthermore, it also includes strain gauges attached to the side of the anti-seepage wall model for measuring concrete strain. The strain gauges include horizontal strain gauges and vertical strain gauges. The horizontal strain gauges are arranged in several rows from top to bottom, with each row located in the middle of the trench section and at the joint of the trench section. The vertical strain gauges are arranged in several rows from top to bottom, with each row located in the middle of the trench section.

[0012] Furthermore, the horizontal lateral actuator, the horizontal axial actuator, and the vertical actuator are all equipped with load sensors to measure the applied load. The load sensors are electrically connected to dial gauges, strain gauges, and a separate data acquisition instrument and computer to form an automatic data acquisition system. The horizontal lateral actuator, horizontal axial actuator, and vertical actuator are all connected to the same control cabinet and are automatically controlled by a computer through software. They can apply loads at a constant displacement rate or a constant load change rate.

[0013] Secondly, this invention proposes a test method for a stress-deformation model of a seepage-proof wall with grooved joints, comprising: Cast the impermeable wall model and then cure the impermeable wall model; Place the cured impermeable wall model into the self-reaction frame and fix it in place; Strain gauges are attached to predetermined positions on the side of the anti-seepage wall model, dial gauges are installed, and the model is connected to the data acquisition instrument via a data cable. Using a constant displacement rate mode, the loading heads of the horizontal axial actuator, vertical actuator, and horizontal lateral actuator are controlled to just contact the seepage barrier model, and the automatic data acquisition system for load, displacement, and strain is activated. A constant load change rate mode is adopted, a target load is preset, the required axial load is applied through the horizontal axial actuator, and the required vertical load is applied through the vertical actuator. The horizontal load is applied step by step by the horizontal lateral actuator. When the horizontal load reaches the preset target value or the seepage barrier wall model is destroyed, the loading is stopped and the loads in all directions are removed. Different combinations of axial loads, vertical loads, and lateral horizontal loads are applied to the cutoff wall model to simulate different stress states; data from displacement and strain measuring points on the cutoff wall model are collected; based on the collected data, the stress-deformation law of the cutoff wall model under different stress states is determined; wherein, the cutoff wall model is one or more models cast in different ways.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) The present invention provides a test device for the stress and deformation model of a cutoff wall with groove joints. The device is based on a self-reaction frame and is precisely loaded by a horizontal lateral actuator, a horizontal axial actuator and a vertical actuator. It can comprehensively and accurately simulate the multi-directional stress state of a cutoff wall with groove joints under controlled conditions, and provide a reliable test method for the design optimization, safety assessment and seismic performance research of cutoff walls.

[0015] (2) The test model of the anti-seepage wall in this invention includes the joint of the trench section, which is significantly different from the traditional calculation and analysis that treats the anti-seepage wall as a whole. It is more in line with the actual engineering situation of the anti-seepage wall, and the test results obtained are more valuable for reference. Attached Figure Description

[0016] Figure 1This is a top view of a test device for a seepage barrier wall with grooved joints according to an embodiment of the present invention.

[0017] Figure 2 This is a front view of a test device for a seepage barrier wall with grooved joints according to an embodiment of the present invention.

[0018] Figure 3 This is a diagram showing the arrangement of measuring points on the side of a seepage barrier wall model with a grooved joint, as proposed in an embodiment of the present invention. Explanation of reference numerals in the attached drawings: 1. Self-reactive frame; 2. Horizontal lateral actuator; 3. Horizontal axial actuator; 4. Vertical actuator; 5. Column; 6. End pad; 7. End support; 8. Dial gauge holder; 9. Dial gauge; 10. Strain gauge; 11. Impermeable wall model. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use.

[0020] Example 1:

[0021] This embodiment proposes a test device for a seepage barrier wall under stress and deformation model with grooved joints, including a self-reaction frame 1, a horizontal lateral actuator 2, a horizontal axial actuator 3, a vertical actuator 4, a column 5, an end pad 6, an end support 7, a dial indicator fixing frame 8, a dial indicator 9, a strain gauge 10, and a seepage barrier wall model 11, the top view and front view of which are shown below. Figure 1 and Figure 2 As shown.

[0022] The self-reaction frame 1 is a cube, 200cm long, 120cm wide, and 100cm high. It is made of 12 No. 10 channel steel welded together and includes 4 corner columns, 2 long beams and 2 short beams at the top, and 2 long beams and 2 short beams at the bottom.

[0023] The anti-seepage wall model 11 is 150cm long, 6.5cm thick, and 60cm high. It is constructed from five 30cm long sections, each with four joints, and is made of concrete. The anti-seepage wall model 11 is placed on the long beam at the bottom of the self-reaction frame 1. End pads 6 are placed at the bottom of both ends, so that the middle of the anti-seepage wall model 11 is suspended. One end of the anti-seepage wall model 11 is tightly attached to a corner column of the self-reaction frame 1 to constrain its axial displacement.

[0024] The horizontal lateral actuators 2 are arranged in three identical rows from top to bottom, with five actuators in each row. They are used to apply horizontal loads to the cutoff wall model 11, simulating the equivalent effects of soil pressure and water pressure. In the same vertical row, the loading point is located at the middle of the horizontal direction of a single trench segment; in the same horizontal row, the loading points are located at 1 / 4, half, and 3 / 4 of the height of the cutoff wall model 11, respectively. The horizontal lateral actuators 2 are fixed to the columns 5 by bolts. The columns 5 are channel steel, welded to the self-reaction frame 1.

[0025] The horizontal axial actuator 3 is fixed to a corner column of the self-reactive frame 1 and connected by bolts. It is used to apply axial load to the anti-seepage wall model 11, and the loading point is located at the center of the end side of the anti-seepage wall model 11.

[0026] The vertical actuator 4 is fixed to a long beam on the upper part of the self-reactive frame 1 and is connected by bolts. It is used to apply vertical load to the anti-seepage wall model 11, and the loading point is located at the center of the top surface of the anti-seepage wall model 11.

[0027] The end support 7 is a square steel rod, which is vertically inserted into the pre-drilled hole of the self-reaction frame 1 to block the horizontal displacement at both ends of the anti-seepage wall model 11. The end support 7 can be pulled out vertically.

[0028] The dial indicator mounting bracket 8 is welded from a steel rod and is used to mount the dial indicator 9.

[0029] Dial gauge 9 is used to measure the horizontal displacement at different locations on the anti-seepage wall model 11. It is arranged in three identical rows from top to bottom, with eight gauges in each row. The measuring points are located on both sides of the joint of the anti-seepage wall trench section. Figure 3 As shown.

[0030] Strain gauges 10 are attached to the side of the anti-seepage wall model 11 to measure concrete strain. They are arranged in three rows from top to bottom. Each row has horizontal strain gauges 10 attached in the middle of the anti-seepage wall trench and at the joints between trench sections. The middle row has vertical strain gauges 10 attached in the middle of the trench section. Figure 3 As shown.

[0031] The horizontal lateral actuator 2, the horizontal axial actuator 3, and the vertical actuator 4 are all equipped with load sensors to measure the applied load. They are electrically connected to the dial gauge 9, strain gauge 10, and a separate data acquisition instrument and computer to form an automatic data acquisition system.

[0032] The horizontal lateral actuator 2, the horizontal axial actuator 3, and the vertical actuator 4 are all connected to the same control cabinet and are automatically controlled by a computer through software. They can apply loads at a constant displacement rate or a constant load change rate.

[0033] Example 2:

[0034] This embodiment proposes a test device for a seepage barrier wall stress deformation model with groove joints as another implementation method. The seepage barrier wall model 11 in this device is composed of 4 groove segments spliced ​​together. While keeping the total length of the model 150cm, thickness 6.5cm, and height 60cm unchanged, the model is divided into 6 groove segments, each 25cm long, and 5 groove joints are formed between adjacent groove segments. The horizontal lateral actuators 2 are arranged in 5 identical rows from top to bottom, with 6 in each row. The dial gauges 9 are used to measure the horizontal displacement at different positions of the seepage barrier wall model 11, and are arranged in 5 identical rows from top to bottom, with 10 in each row. The measuring points are located on both sides of the seepage barrier wall groove joints. The remaining structures, including the self-reaction frame 1, horizontal axial actuators 3, vertical actuators 4, end pads 6, end supports 7, dial gauge fixing frame 8, strain gauges 10, etc., are the same as in Embodiment 1, and will not be described again here.

[0035] Example 3:

[0036] Based on Example 1, this embodiment proposes a test method for a seepage barrier wall with grooved joints under stress and deformation, including the following steps: S1: Concrete Cutoff Wall Model 11. Erect the casting template for the cutoff wall model 11, dividing it into five equal-span slots, numbered I, II, III, IV, and V. Separators are installed between the slots. The sides of the separators can be machined to have a certain roughness to simulate the joints formed by milling; or the separators can be machined into an arc shape to simulate the joints formed by pipe splicing. Concrete is poured in two stages. In the first stage, slots I, III, and V are poured. After the concrete has initially set, slurry is poured into slots II and IV. After standing for one day, the concrete pouring guide is inserted into the bottom of the slurry, and the second-stage concrete is poured into slots II and IV. The slurry is discharged by lifting the concrete surface until all concrete is poured into slots II and IV. Four connection points are formed between the second-stage concrete and the first-stage concrete. After the second-phase concrete has initially set, the pouring formwork will be removed, and the concrete will be watered and cured for 28 days for future use.

[0037] S2: Pull out the end support 7 of the test device, place the cured seepage barrier model 11 on the end pad 6 of the test device, insert the end support 7, and move the seepage barrier model 11 so that one end is in close contact with the corner column of the self-reaction frame 1 and the side is in close contact with the end support 7.

[0038] S3: Attach strain gauges 10 and dial gauges 9 to predetermined positions on the side of the anti-seepage wall model 11, and connect them to the data acquisition instrument via data cables.

[0039] S4: Start the computer control software, adopt the constant displacement rate mode, and control the loading heads of the horizontal axial actuator 3, vertical actuator 4 and 15 horizontal lateral actuators 2 to just contact the seepage barrier model 11; start the automatic acquisition system for load, displacement and strain data.

[0040] S5: Using a constant load change rate mode and a preset target load, the required axial load is applied through the horizontal axial actuator 3 and the required vertical load is applied through the vertical actuator 4. The specific load values ​​are shown in Table 1, Scheme A below.

[0041] S6: Apply horizontal loads step by step through 15 horizontal lateral actuators 2. The specific load values ​​are shown in Table 1, Scheme A below. When the horizontal load reaches the preset target value or the seepage barrier wall is damaged, stop loading and unload the loads in all directions.

[0042] S7: According to the other load application schemes in Table 1, use different combinations of axial load, vertical load and lateral horizontal load to simulate the seepage barrier wall under different stress states. Repeat S5 and S6, draw the variation law of displacement and strain of each measuring point of the seepage barrier wall model 11 with the horizontal load, and analyze the difference of stress deformation law of the seepage barrier wall under different stress states.

[0043] Table 1 Load Application Scheme (kN)

[0044] S8: Cast a cutoff wall model 11 including groove joints of different shapes and roughnesses, as well as a cutoff wall model without groove joints. Repeat S2~S7. Analyze the influence of different groove joints on the stress and deformation law of the cutoff wall by measuring the displacement and strain change law of each measuring point of the cutoff wall model 11, and the difference in stress and deformation law of the cutoff wall with and without groove joints.

[0045] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to explain the relative positional relationship and movement between components in a specific orientation. If the specific orientation changes, the directional indication will also change accordingly. These terms are used only for the convenience of describing this application and for simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0046] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0047] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0048] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A test device for a seepage barrier wall under stress and deformation, comprising a grooved joint, characterized in that, Includes a self-reactive force frame (1), a horizontal lateral actuator (2), a horizontal axial actuator (3), a vertical actuator (4), a column (5), a dial indicator (9), and a seepage barrier model (11). The self-reactive frame (1) is used to support the impermeable wall model (11) and provide reaction force support; The anti-seepage wall model (11) is formed by casting several sections in sequence, and a joint is formed between adjacent sections; the first end of the anti-seepage wall model (11) is connected to the first end of the horizontal axial actuator (3), and the second end is connected to the self-reaction frame (1), which is used to simulate the anti-seepage wall structure and bear the load. The column (5) is fixedly connected to the self-reactive frame (1); The first end of the horizontal lateral actuator (2) is fixedly connected to the column (5), and the second end is connected to the anti-seepage wall model (11) to apply a horizontal load to the anti-seepage wall model (11); The second end of the horizontal axial actuator (3) is fixedly connected to the self-reactive frame (1) and is used to apply axial load to the anti-seepage wall model (11); The first end of the vertical actuator (4) is fixedly connected to the self-reactive force frame (1), and the second end is connected to the anti-seepage wall model (11) to apply vertical load to the anti-seepage wall model (11); The dial gauge (9) is connected to the anti-seepage wall model (11) and is used to measure the horizontal displacement at different positions of the anti-seepage wall model (11).

2. The test device for the stress and deformation model of the seepage-proof wall with grooved joints according to claim 1, characterized in that, The self-reactive force frame (1) is a cube, including 4 corner columns, 2 long beams and 2 short beams set at the top, and 2 long beams and 2 short beams set at the bottom.

3. The test device for the stress and deformation model of the seepage-proof wall with grooved joints according to claim 2, characterized in that, The second end of the anti-seepage wall model (11) is closely attached to a corner column of the self-reaction frame (1), and the bottom of both ends is supported by end pads (6) on the long beam at the bottom of the self-reaction frame (1), with the middle part suspended.

4. The test device for the stress and deformation model of the seepage-proof wall with grooved joints according to claim 1, characterized in that, The horizontal lateral actuators (2) are arranged in a matrix. The horizontal lateral actuators (2) in the same horizontal row are located on the same horizontal line, and the horizontal lateral actuators (2) in the same vertical row are located on the same vertical line. The number of horizontal lateral actuators (2) in each horizontal row is equal to the number of trench segments in the anti-seepage wall model (11).

5. The test device for the stress and deformation model of the seepage-proof wall with grooved joints according to claim 1, characterized in that, The dial gauge (9) is fixed to the dial gauge mounting bracket (8), and the probe of the dial gauge (9) is in contact with the anti-seepage wall model (11). The dial gauges (9) are arranged in several rows from top to bottom. The number of dial gauges (9) in each row is twice the number of the trench joints. One dial gauge is set on each side of each trench joint.

6. The test apparatus for the stress-deformation model of the seepage-proof wall with grooved joints according to claim 1, characterized in that, It also includes end supports (7), which are square steel rods that are vertically inserted into the pre-drilled holes of the self-reaction frame (1) to block the horizontal displacement at both ends of the anti-seepage wall model (11), and the end supports (7) can be vertically pulled out.

7. The test device for the stress-deformation model of the seepage-proof wall with grooved joints according to claim 1, characterized in that, It also includes strain gauges (10) attached to the side of the anti-seepage wall model (11) for measuring concrete strain. The strain gauges (10) include horizontal strain gauges and vertical strain gauges. The horizontal strain gauges are divided into several rows from top to bottom, with each row located in the middle of the trench section and at the joint of the trench section. The vertical strain gauges are divided into several rows from top to bottom, with each row located in the middle of the trench section.

8. The test apparatus for the stress-deformation model of the seepage-proof wall with grooved joints according to claim 7, characterized in that, The horizontal lateral actuator (2), the horizontal axial actuator (3), and the vertical actuator (4) are all equipped with load sensors for measuring the applied load. The load sensors are electrically connected to the data acquisition instrument and the computer to form an automatic data acquisition system.

9. The test apparatus for the stress-deformation model of the seepage-proof wall with grooved joints according to claim 7, characterized in that, The horizontal lateral actuator (2), the horizontal axial actuator (3), and the vertical actuator (4) are connected to the same control cabinet, which controls the loading mechanism to apply load at a constant displacement rate or a constant load change rate.

10. A test method for a stress-deformation model of a seepage-proof wall with grooved joints, characterized in that, The test apparatus for stress-deformation model of the seepage-proof wall with grooved joint as described in any one of claims 1 to 9 comprises: Cast the anti-seepage wall model (11) and cure the anti-seepage wall model (11); The cured impermeable wall model (11) is placed on the self-reaction frame (1) and fixed; Strain gauges (10) are attached to predetermined positions on the side of the anti-seepage wall model (11), dial gauges (9) are installed, and the model is connected to the data acquisition instrument via a data cable. Using a constant displacement rate mode, the loading heads of the horizontal axial actuator (3), vertical actuator (4) and horizontal lateral actuator (2) are controlled to just contact the seepage barrier model (11). Using a constant load change rate mode, a target load is preset, and the required axial load is applied through the horizontal axial actuator (3), and the required vertical load is applied through the vertical actuator (4). The horizontal load is applied step by step by the horizontal lateral actuator (2). When the horizontal load reaches the preset target value or the seepage barrier wall model (11) is destroyed, the loading is stopped and the loads in all directions are removed. Different combinations of axial loads, vertical loads and lateral horizontal loads are applied to the anti-seepage wall model (11) to simulate different stress states; data of displacement measuring points and strain measuring points on the anti-seepage wall model (11) are collected; the stress deformation law of the anti-seepage wall model (11) under different stress states is determined based on the collected data; wherein, the anti-seepage wall model (11) is one or more models cast in different ways.

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