Annular concrete support structure deterioration test device and method with specified internal and external water pressure

Abstract

The invention discloses a deterioration test device and method for an annular concrete support structure with specified internal and external water pressures, and the method comprises the steps: 1, simulating tunnel support: vertically placing an annular concrete test piece, thereby simulating a real tunnel support structure; the ratio of the inner diameter of the real tunnel supporting structure to the inner diameter of the annular concrete test piece is set as shown in the specification, and the ratio of the radial thickness of the real tunnel supporting structure to the radial thickness of the annular concrete test piece is set as shown in the specification; 2, a water pressure sensor is arranged; 3, an inner water cavity is formed; 4, an outer water cavity is formed; 5, a degradation test is conducted, specifically, by injecting water into the inner water cavity or the outer water cavity, the inner water working condition and the outer water working condition of the real tunnel supporting structure are simulated; and step 6, carrying out degradation detection. Different working conditions can be set according to internal and external water, so that the working states of the corresponding water flow control holes are selected, and the degradation process of the supporting structure under different internal and external water pressure conditions can be simulated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tunnel support, in particular to a ring-shaped concrete support structure degradation test device and method for specifying internal and external water pressure. BACKGROUND

[0002] With the rapid development of transportation and water conservancy construction in China, the working environment of tunnel support system is increasingly complex and deteriorates with the increase of service life. Tunnel support is prone to deterioration. Tunnel support mainly bears the water pressure of internal and external water conditions, specifically:

[0003] Internal water condition: during tunnel operation, the tunnel is water, and the water pressure in the tunnel above the groundwater level.

[0004] External water condition: during tunnel construction, the tunnel is waterless, and the external groundwater pressure below the groundwater level.

[0005] Therefore, it is urgent to develop a ring-shaped concrete support structure degradation test device for specifying internal and external water pressure to study the long-term deterioration law and durability of the support structure. SUMMARY

[0006] The technical problem to be solved by the present application is to solve the above-mentioned deficiencies of the prior art, and to provide a ring-shaped concrete support structure degradation test device and method for specifying internal and external water pressure, which can more realistically simulate the stress characteristics of the support structure underground.

[0007] To solve the above technical problems, the technical scheme adopted by the present application is:

[0008] A ring-shaped concrete support structure degradation test method for specifying internal and external water pressure, comprising the following steps.

[0009] Step 1, simulate tunnel support: vertically place the ring-shaped concrete test piece to simulate the real tunnel support structure; the ratio of the internal diameter of the real tunnel support structure to the internal diameter of the ring-shaped concrete test piece is , the ratio of the radial thickness of the real tunnel support structure to the radial thickness of the ring-shaped concrete test piece is , and .

[0010] Step 2, set the water pressure sensor: set the internal pressure sensor and the external pressure sensor on the inner wall and the outer wall of the ring-shaped concrete test piece.

[0011] Step 3, set the internal water cavity: seal the circular inner cavity of the ring-shaped concrete test piece to form an internal water cavity, and set an internal water inlet hole and an internal water outlet hole on the internal water cavity.

[0012] Step 4: Set up an external water cavity: Set up a sealed annular space around the annular concrete specimen to form an external water cavity, and set external water injection holes and external drainage holes on the external water cavity.

[0013] Step 5, Deterioration Test: By injecting water into the internal or external water cavity, the internal and external water conditions of the actual tunnel support structure are simulated. Specifically:

[0014] A. Simulate internal water conditions: Connect the water pump to the internal water injection hole, and seal the internal drainage hole and the external water injection hole. Inject water into the internal water cavity until the internal pressure sensor detects that the pressure reaches the internal pressure set value, causing the annular concrete specimen to deteriorate. During the test, remove the seeping water from the external water cavity in a timely manner through the external drainage hole.

[0015] B. Simulate external water conditions: Connect the water pump to the external water injection hole, and seal the external drainage hole and the internal water injection hole. Inject water into the external water cavity until the external pressure sensor detects that the pressure reaches the external pressure set value, causing the annular concrete specimen to deteriorate. During the test, remove the seeping water from the internal water cavity in a timely manner through the internal drainage hole.

[0016] Step 6, Deterioration Detection: Drain the water from the inner or outer water cavity and remove the annular concrete specimen for deterioration depth detection.

[0017] In step 4, the radial thickness of the outer water cavity is not less than the radial thickness of the annular concrete specimen.

[0018] In step 5A, the internal pressure setting value is set according to the maximum internal water pressure that the actual tunnel support structure needs to withstand during tunnel operation, and is less than the maximum internal water pressure. Its specific value is determined by the values ​​of m and n.

[0019] In step 5B, the external pressure setting value is set according to the maximum external groundwater pressure that the actual tunnel support structure needs to withstand during tunnel construction, and is less than the maximum external groundwater pressure. Its specific value is determined by the values ​​of m and n.

[0020] In step 6, the degradation depth is detected using either the phenolphthalein method or the calcium-silicon method.

[0021] In step 1, because Therefore, when the internal pressure setting value in step 5 is less than the maximum internal water pressure that the actual tunnel support structure needs to withstand, and the external pressure setting value is less than the maximum external groundwater pressure that the actual tunnel support structure needs to withstand, similar stress can be achieved, and the test head requirement can be reduced. The specific choice depends on the required reduction in the test head ratio.

[0022] A test apparatus for the deterioration of annular concrete support structures under specified internal and external water pressure, comprising a support, a bottom shell, a cover plate, and an elastic water-resistant membrane.

[0023] The bottom shell is vertically mounted on the support. The bottom shell has a cylindrical cavity and an internal thread on the top inner side.

[0024] The cover plate has an external thread that extends into a cylindrical cavity, and the external thread can seal with the internal thread through a threaded pair.

[0025] The annular concrete specimen consists of the specimen body and an elastic water-resistant membrane disposed on the top and bottom surfaces of the specimen body.

[0026] The annular concrete specimen is placed inside the cylindrical cavity on the inner side of the external thread of the cover plate, and is in contact with and sealed to the bottom shell and the cover plate respectively. The annular cavity on the outer side of the annular concrete specimen forms the outer water cavity; the cylindrical cavity on the inner side of the annular concrete specimen forms the inner water cavity.

[0027] The bottom shell has an internal drainage hole connected to the internal water cavity at its center, and an external drainage hole connected to the external water cavity at its outer edge; the cover plate has an internal water injection hole connected to the internal water cavity at its center, and an external water injection hole connected to the external water cavity at its outer edge.

[0028] The radial thickness of the outer water cavity formed between the inner wall of the cover plate's external thread and the outer wall of the annular concrete specimen is provided in this space, which contains an external drainage hole and an external water injection hole. The radial thickness must be greater than the maximum diameter of the external drainage hole and the external water injection hole.

[0029] The elastic water-blocking membrane located on the top surface of the specimen body is bonded to both the specimen body and the cover plate; the elastic water-blocking membrane located on the bottom surface of the specimen body is bonded to both the specimen body and the bottom shell.

[0030] The present invention has the following beneficial effects:

[0031] 1. This invention can more realistically simulate the stress characteristics of support structures underground.

[0032] 2. This invention can select the working state of the corresponding water flow control hole according to different working conditions of internal and external water settings, and can simulate the deterioration process of the support structure under different internal and external water pressure conditions. Attached Figure Description

[0033] Figure 1 An exploded view of the test apparatus for the deterioration of annular concrete support structures under specified internal and external water pressures according to the present invention is shown.

[0034] Figure 2 A perspective view of the test apparatus for the deterioration of annular concrete support structures under specified internal and external water pressures according to the present invention is shown.

[0035] Figure 3 A schematic diagram of the cover plate in this invention is shown.

[0036] Figure 4 The three-dimensional structure of the bottom shell in this invention is shown. Figure 1 .

[0037] Figure 5 The three-dimensional structure of the bottom shell in this invention is shown. Figure 2 .

[0038] Figure 6 The diagram shows the structure of the annular concrete specimen after the elastic water-blocking membrane is pasted on both sides.

[0039] Figure 7 A schematic diagram of the support structure in this invention is shown.

[0040] Figure 8 A diagram showing the relative positions of the various structures in this invention is displayed.

[0041] Among them are:

[0042] 1. Cover plate; 1-1. Inner water inlet hole; 1; 1-2. Outer water inlet hole; 2; 1-3. Circular plate; 1-4. External thread of cover plate;

[0043] 2. Bottom shell; 2-1. Shell; 2-2. Internal thread; 2-3. Internal drain hole; 2-4. External drain hole;

[0044] 3. Bracket;

[0045] 4. Circular concrete specimen; 4-1. Specimen body; 4-2. Elastic water-resistant membrane. Detailed Implementation

[0046] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0047] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0048] like Figure 1 and Figure 2 As shown, the test apparatus for the deterioration of annular concrete support structure under specified internal and external water pressure includes a cover plate 1, a bottom shell 2, a support 3, and annular concrete specimen 4.

[0049] Preferred support structure, such as Figure 7As shown, there are four support rods, and the bottom surface of the support rods is provided with an inwardly inclined support slope. Alternatively, the support can also be a support platform with a V-shape or arc shape at the top.

[0050] The bottom shell is vertically mounted on a support, such as Figure 4 and Figure 5 As shown, the bottom shell includes a shell 2-1, which has a cylindrical cavity. An internal thread 2-2 is provided on the top inner side of the shell. An internal drainage hole 2-3 is provided at the center of the bottom shell, and an external drainage hole 2-4 is provided on the outer edge of the bottom shell.

[0051] like Figure 3 As shown, the cover plate includes a circular plate 1-3. The outer edge of the bottom surface of the circular plate has an external thread 1-4 that extends into a cylindrical cavity. The external thread can seal with the internal thread through a threaded pair. An internal water injection hole 1-1 is provided at the center of the cover plate, and an external water injection hole 1-2 is provided at the outer edge of the cover plate.

[0052] like Figure 6 As shown, the annular concrete specimen includes a specimen body 4-1 and an elastic water-blocking membrane 4-2 disposed on the top and bottom surfaces of the specimen body.

[0053] The annular concrete specimen is placed inside the cylindrical cavity on the inner side of the external thread of the cover plate, and is in contact with and sealed to the bottom shell and the cover plate respectively. The annular cavity on the outer side of the annular concrete specimen forms an outer water cavity, which is connected to the outer water injection hole and the outer drainage hole respectively. The cylindrical cavity on the inner side of the annular concrete specimen forms an inner water cavity, which is connected to the inner water injection hole and the inner drainage hole respectively.

[0054] Furthermore, the radial thickness of the outer water cavity formed between the inner wall of the cover plate's external thread and the outer wall of the annular concrete specimen is provided in this space, and the radial thickness must be greater than the maximum diameter of the outer drainage hole and the outer water injection hole.

[0055] The elastic water-blocking membrane located on the top surface of the specimen body is bonded to both the specimen body and the cover plate; the elastic water-blocking membrane located on the bottom surface of the specimen body is bonded to both the specimen body and the bottom shell.

[0056] A method for testing the deterioration of annular concrete support structures under specified internal and external water pressures includes the following steps.

[0057] Step 1: Simulate Tunnel Support: Place the annular concrete specimen vertically to simulate the actual tunnel support structure; let the ratio of the inner diameter of the actual tunnel support structure to the inner diameter of the annular concrete specimen be _____. The ratio of the radial thickness of the actual tunnel support structure to the radial thickness of the annular concrete specimen is: ,and .

[0058] The above-mentioned method for vertically placing concrete specimens preferably includes the following steps.

[0059] Step 1-1: Adhere elastic water-resistant membranes to the top and bottom surfaces of the specimen to form a ring-shaped concrete specimen.

[0060] Step 1-2: Seal the annular concrete specimen from Step 1-1 on the bottom surface of the inner cavity of the bottom shell between the inner and outer drainage holes.

[0061] Steps 1-3: Apply adhesive between the inner and outer water injection holes and at the contact point with the elastic water-blocking membrane, and engage the outer thread of the cover plate with the inner thread of the bottom shell. The cover plate, the annular concrete specimen, and the bottom shell are axially pressed and bonded together, so that seepage can only occur radially through the annular concrete specimen.

[0062] Step 2: Set up water pressure sensors: Set up internal pressure sensors and external pressure sensors on the inner and outer walls of the annular concrete specimen, respectively.

[0063] Step 3: Set up the inner water cavity: Seal the circular inner cavity of the annular concrete specimen to form an inner water cavity, and set an inner water injection hole and an inner drainage hole on the inner water cavity. In this embodiment, the inner cavity of the annular concrete specimen forms an inner water cavity that is connected to both the inner water injection hole and the inner drainage hole.

[0064] Step 4: Setting up an external water cavity: A sealed annular space is set around the annular concrete specimen to form an external water cavity, and an external water injection hole and an external drainage hole are set on the external water cavity. In this embodiment, an external water cavity is formed between the annular concrete specimen and the bottom shell, both of which are connected to the external water injection hole and the external drainage hole. Furthermore, the radial thickness of the external water cavity is preferably not less than the radial thickness of the annular concrete specimen.

[0065] Step 5, Deterioration Test: By injecting water into the internal or external water cavity, the internal and external water conditions of the actual tunnel support structure are simulated. Specifically:

[0066] A. Simulate internal water conditions: Connect the water pump to the internal water injection hole, and seal the internal drainage hole and the external water injection hole. Inject water into the internal water cavity until the internal pressure sensor detects that the pressure reaches the internal pressure set value, causing the annular concrete specimen to deteriorate.

[0067] The aforementioned internal pressure setting is based on the maximum internal water pressure that the actual tunnel support structure needs to withstand during tunnel operation, and is less than the maximum internal water pressure.

[0068] During the simulation of the internal water condition, by inserting the suction pipe into the external drainage hole, the seepage water in the external water cavity is sucked out, thereby maintaining the pressure difference on both sides of the annular concrete specimen and ensuring that the water in the internal water cavity continues to seep into the external water cavity and deteriorate radially under the internal water condition.

[0069] B. Simulate external water conditions: Connect the water pump to the external water injection hole, and seal the external drainage hole and the internal water injection hole. Inject water into the external water cavity until the external pressure sensor detects that the pressure reaches the external pressure set value, causing the annular concrete specimen to deteriorate.

[0070] The aforementioned external pressure setting is based on the maximum external groundwater pressure that the actual tunnel support structure needs to withstand during tunnel construction, and is less than the maximum external groundwater pressure.

[0071] During the simulation of external water conditions, by inserting the suction pipe into the internal drainage hole, the seepage water in the internal water cavity is sucked out, thereby maintaining the pressure difference on both sides of the annular concrete specimen and ensuring that under external water conditions, the water in the external water cavity continues to seep into the internal water cavity and deteriorates radially.

[0072] Because in step 1 Therefore, when the internal pressure setting value in step 5 is less than the maximum internal water pressure that the actual tunnel support structure needs to withstand, and the external pressure setting value is less than the maximum external groundwater pressure that the actual tunnel support structure needs to withstand, similar stress can be achieved, and the test head requirement can be reduced. The specific choice depends on the required reduction in the test head ratio.

[0073] Inner radius of the annular concrete specimen axial thickness outer radius .in, and These represent the inner radius and axial thickness of the actual tunnel support structure, respectively.

[0074] For real tunnel support structures, based on the formula for circumferential stress in thin-walled cylinders:

[0075]

[0076] In the formula, This represents the circumferential stress of a real tunnel support structure.

[0077] This represents the head pressure of the actual tunnel support structure.

[0078] This is the outer radius of the actual tunnel support structure.

[0079] The stress similarity conditions between the model (ring-shaped concrete specimen) and the prototype (real tunnel support structure) are set to ensure that the stresses in the model and the prototype are equal. ,have to:

[0080]

[0081] In the formula, The water head pressure of the model.

[0082] Substituting the geometric relationships, we obtain the water pressure similarity ratio:

[0083]

[0084] Under thin-walled conditions, Approximately:

[0085]

[0086] By selecting , can make This allows for stress similarity under lower water pressure, reducing the required test head.

[0087] Step 6, Deterioration Detection: Drain the water from the inner or outer water cavity and remove the annular concrete specimen. Preferably, the phenolphthalein method or calcium-silicon method is used to detect the depth of deterioration.

[0088] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A method for testing the deterioration of a ring-shaped concrete support structure under specified internal and external water pressure, characterized in that: Includes the following steps: Step 1: Simulate Tunnel Support: Place the annular concrete specimen vertically to simulate the actual tunnel support structure; let the ratio of the inner diameter of the actual tunnel support structure to the inner diameter of the annular concrete specimen be _____. The ratio of the radial thickness of the actual tunnel support structure to the radial thickness of the annular concrete specimen is: ,and ; Step 2: Install water pressure sensors: Install internal pressure sensors and external pressure sensors on the inner and outer walls of the annular concrete specimen, respectively; Step 3: Set up the inner water cavity: Seal the circular inner cavity of the annular concrete specimen to form an inner water cavity, and set an inner water injection hole and an inner drainage hole on the inner water cavity; Step 4: Set up an external water cavity: Set up a sealed annular space around the annular concrete specimen to form an external water cavity, and set external water injection holes and external drainage holes on the external water cavity; Step 5, Deterioration Test: By injecting water into the internal or external water cavity, the internal and external water conditions of the actual tunnel support structure are simulated. Specifically: A. Simulate internal water conditions: Connect the water pump to the internal water injection hole, and seal the internal drainage hole and the external water injection hole. Inject water into the internal water cavity until the internal pressure sensor detects that the pressure reaches the internal pressure set value, causing the annular concrete specimen to deteriorate. During the test, remove the seeping water from the external water cavity through the external drainage hole. B. Simulate external water conditions: Connect the water pump to the external water injection hole, and seal the external drainage hole and the internal water injection hole. Inject water into the external water cavity until the external pressure sensor detects that the pressure reaches the external pressure set value, causing the annular concrete specimen to deteriorate. During the test, remove the seeping water from the internal drainage hole from the internal water cavity. Step 6, Deterioration Detection: Drain the water from the inner or outer water cavity and remove the annular concrete specimen for deterioration depth detection.

2. The method for testing the deterioration of annular concrete support structures under specified internal and external water pressures according to claim 1, characterized in that: In step 4, the radial thickness of the outer water cavity is not less than the radial thickness of the annular concrete specimen.

3. The method for testing the deterioration of annular concrete support structures under specified internal and external water pressures according to claim 1, characterized in that: In step 5A, the internal pressure setting value is set according to the maximum internal water pressure that the actual tunnel support structure needs to withstand during tunnel operation, and is less than the maximum internal water pressure. Its specific value is determined by the values ​​of m and n.

4. The method for testing the deterioration of annular concrete support structures under specified internal and external water pressures according to claim 1, characterized in that: In step 5B, the external pressure setting value is set according to the maximum external groundwater pressure that the actual tunnel support structure needs to withstand during tunnel construction, and is less than the maximum external groundwater pressure. Its specific value is determined by the values ​​of m and n.

5. The method for testing the deterioration of annular concrete support structures under specified internal and external water pressures according to claim 1, characterized in that: In step 6, the degradation depth is detected using either the phenolphthalein method or the calcium-silicon method.

6. The method for testing the deterioration of annular concrete support structures under specified internal and external water pressures according to claim 1, characterized in that: In step 1, because Therefore, when the internal pressure setting value in step 5 is less than the maximum internal water pressure that the actual tunnel support structure needs to withstand, and the external pressure setting value is less than the maximum external groundwater pressure that the actual tunnel support structure needs to withstand, similar stress can be achieved, and the test head requirement can be reduced. The specific choice depends on the required reduction in the test head ratio.

7. A test apparatus for the deterioration of annular concrete support structures under specified internal and external water pressure, characterized in that: Includes a support frame, base shell, cover plate, and elastic water-resistant membrane; The bottom shell is vertically mounted on the support, and the bottom shell has a cylindrical cavity. The top inner side of the bottom shell is provided with internal threads. The cover plate has an external thread that extends into a cylindrical cavity, and the external thread can seal with the internal thread through the thread pair. The annular concrete specimen includes the specimen body and an elastic water-blocking membrane disposed on the top and bottom surfaces of the specimen body; The annular concrete specimen is placed inside the cylindrical cavity on the inner side of the external thread of the cover plate, and is in contact with and sealed to the bottom shell and the cover plate respectively. The annular cavity on the outer side of the annular concrete specimen forms the outer water cavity; the cylindrical cavity on the inner side of the annular concrete specimen forms the inner water cavity.

8. The test apparatus for deterioration of annular concrete support structure under specified internal and external water pressure as described in claim 7, characterized in that: The bottom shell has an internal drainage hole connected to the internal water cavity at its center, and an external drainage hole connected to the external water cavity at its outer edge; the cover plate has an internal water injection hole connected to the internal water cavity at its center, and an external water injection hole connected to the external water cavity at its outer edge.

9. The test apparatus for deterioration of annular concrete support structure under specified internal and external water pressure as described in claim 7, characterized in that: The radial thickness of the outer water cavity formed between the inner wall of the cover plate's external thread and the outer wall of the annular concrete specimen is provided in this space, which contains an external drainage hole and an external water injection hole. The radial thickness must be greater than the maximum diameter of the external drainage hole and the external water injection hole.

10. The test apparatus for deterioration of annular concrete support structure under specified internal and external water pressure according to claim 7, characterized in that: The elastic water-blocking membrane located on the top surface of the specimen body is bonded to both the specimen body and the cover plate; the elastic water-blocking membrane located on the bottom surface of the specimen body is bonded to both the specimen body and the bottom shell.

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