True triaxial stress-chemical multi-field coupling accelerated erosion testing device and method

Abstract

The invention discloses a true triaxial stress-chemical multi-field coupling accelerated erosion testing device, which combines a true triaxial stress test with sample erosion so as to simulate the coupling effect of a concrete structure in a true triaxial stress state and an erosive water environment. The invention also discloses a true triaxial stress-chemical multi-field coupling accelerated erosion test method. Compared with the prior art, the true triaxial stress-chemical multi-field coupling accelerated erosion testing device has the advantages that the erosion time is shortened, the damage condition of concrete under the true triaxial stress-chemical erosion coupling effect can be rapidly tested, and the like.

Description

Technical Field

[0001] The invention relates to the field of water-related infrastructure-concrete structure stress-chemical multi-field coupling testing, and in particular to a true triaxial stress-chemical multi-field coupling accelerated corrosion testing device and method. Background Art

[0002] With the development of the national economy, urban and marine underground projects are changing with each passing day. As an important underground transportation infrastructure, immersed tube tunnels have been widely used. Immersed tube tunnels are usually laid on the bottom of rivers, lakes or oceans. Their construction process involves complex engineering technology and high costs. However, due to the special loads of immersed tube tunnels and long-term water erosion, their structural stability and service life face many challenges. In immersed tube tunnels, concrete structures are often under the coupling of complex stress and corrosive water environment. Accurately revealing the deterioration and damage mechanism of concrete structures under the coupling of stress-chemical erosion is crucial to the design, construction and maintenance of tunnels. Under the stress-chemical coupling, material degradation is prone to occur in concrete structures, resulting in cracks, deformation and even failure, which seriously affects the overall safety of the tunnel.

[0003] The existing multi-field coupling test methods are mainly uniaxial and conventional triaxial tests. However, immersed tube tunnels are often in a true triaxial stress state under extreme conditions, and uniaxial and conventional triaxial tests often cannot fully reveal the properties of concrete. On the other hand, in the existing test methods, due to the problem of test block size, the test time is often as long as several years.

[0004] Therefore, how to provide a true triaxial stress-chemical multi-field coupled accelerated corrosion testing device that can achieve the technical effect of quickly testing concrete structures under the true triaxial stress-chemical coupling is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a true triaxial stress-chemical multi-field coupling accelerated corrosion testing device, so that it can achieve the technical effect of quickly testing concrete structures under the true triaxial stress-chemical coupling.

[0006] To achieve the above-mentioned purpose, the present invention provides a true triaxial stress-chemical multi-field coupled accelerated corrosion testing device, which comprises: a confining pressure structure, which comprises a bottom base, a rigid sleeve and a top base, wherein the rigid sleeve is a cylindrical structure, one end of the rigid sleeve is sealed and connected to the bottom base, and the other end of the rigid sleeve is sealed and connected to the top base, and a first loading hole is opened in the center of the top base; a loading structure, which comprises a lower pressure head and an upper pressure head, wherein one end of the lower pressure head is fixed to the center of the bottom base, and the other end of the lower pressure head is sealed and fixedly connected to one end of a hollow cylindrical sample; one end of the upper pressure head is sealed and fixedly connected to the other end of the hollow cylindrical sample, and the outer sealing sleeve of the hollow cylindrical sample is provided with a heat shrink sleeve; an upper loading structure, wherein the upper loading system includes a lower pressure head and an upper pressure head. It includes an upper pressure loading structure and a torque loading structure, the upper pressure loading structure includes a loading rod and a dividing block, the dividing block is sealingly and rotatably connected to the top base, and a second loading hole is opened in the center of the dividing block; a sealing cover, the sealing cover is located above the top base and is fixedly and sealedly connected to the top base, and a third loading hole is opened in the middle of the sealing cover; a plurality of fixing bolts, and a plurality of the fixing bolts fix the bottom base and the top base along the periphery of the rigid sleeve; wherein one end of the loading rod passes through the third loading hole, the second loading hole, and the first loading hole in sequence and is fixedly connected to the other end of the upper pressure head by a concave-convex key, and the other end of the loading rod is fixedly connected to the torque loading structure; the loading rod is fixedly connected to the dividing block, and the sealing cover and the top base are respectively sealed and rotatably connected to the loading rod.

[0007] In the first aspect, a support platform with a cylindrical structure is provided in the middle of the bottom base, the pressure head is fixed at the center of the support platform, and the inner wall of one end of the rigid sleeve is tightly attached to the side wall cover of the support platform and is arranged on the periphery of the support platform; a first inner hydraulic inlet, a first inner hydraulic outlet and a peripheral hydraulic inlet are provided on the support platform, and the first inner hydraulic inlet is located at the center of the support platform.

[0008] In the first aspect, a lower support block with a cylindrical structure is provided in the middle of the upper part of the lower pressure head, and the inner wall of one end of the hollow cylindrical sample is tightly attached to the side wall cover of the lower support block and is arranged on the periphery of the lower support block; a second inner hydraulic inlet penetrating the lower pressure head is opened in the center of the lower support block, the second inner hydraulic inlet is communicated with the first inner hydraulic inlet, and the first inner hydraulic outlet and the outer hydraulic inlet are located on the outside of the bottom of the lower pressure head.

[0009] In the first aspect, an upper support block with a cylindrical structure is provided in the middle of the lower part of the upper pressure head, and the inner wall of the other end of the hollow cylindrical sample is tightly attached to the side wall cover of the upper support block and is arranged on the periphery of the upper support block; a second inner hydraulic outlet penetrating the upper pressure head is opened on the upper support block, and the second inner hydraulic outlet is sealed and connected to the first inner hydraulic outlet through a hydraulic pipe.

[0010] In the first aspect, the bottom of the top base has a protruding closing cover, and the inner wall of the other end of the rigid sleeve is tightly attached to the side wall cover of the closing cover and is arranged on the periphery of the closing cover; a peripheral hydraulic outlet is opened on the closing cover; wherein a first loading hole is opened in the center of the closing cover, and the closing cover is sealed and rotatably slidably connected to the loading rod.

[0011] In the first aspect, the top of the top base has a accommodating space, the dividing block is located inside the accommodating space and divides the accommodating space into a first accommodating area and a second accommodating area, and the dividing block is sealingly and slidingly connected to the inner wall of the accommodating space; an upper hydraulic inlet is opened on the side wall at the upper end of the first accommodating area, and a lower hydraulic outlet is opened on the side wall at the lower end of the second accommodating area; wherein the sealing cover covers the top end of the accommodating space and is fixedly and sealingly connected to the top of the top base.

[0012] In a first aspect, the torque loading structure includes: an axial loading piston, one end of which is fixedly connected to the other end of the loading rod; and a combined torque transmission mechanism, one end of which is fixedly connected to the combined torque transmission mechanism.

[0013] In the first aspect, the true triaxial stress-chemical multi-field coupled accelerated corrosion device also includes a strain testing structure, which includes: a first strain gauge, which is located in the internal space of the hollow cylindrical specimen; a second strain gauge, which is located inside the rigid sleeve; a first strain cable, one end of which is connected to the first strain gauge; a second strain cable, one end of which is connected to the second strain gauge; wherein a first data transmission channel and a second data transmission channel are also provided on the support platform, the first data transmission channel and the second data transmission channel are located on the outside of the lower pressure head, and a third data transmission channel is also provided on the upper pressure head; the other end of the first strain cable passes through the second data transmission channel and the third data transmission channel in sequence to be connected to the first strain display; the other end of the second strain cable passes through the first data transmission channel to be connected to the second strain display.

[0014] The present invention also provides a true triaxial stress-chemical multi-field coupling accelerated corrosion test method, which is used for testing the true triaxial stress-chemical multi-field coupling accelerated corrosion test device mentioned above. The true triaxial stress-chemical multi-field coupling accelerated corrosion test method specifically comprises: preparing a hollow cylindrical sample, placing a first strain gauge inside the hollow cylindrical sample and connecting a cable, and then installing the hollow cylindrical sample in the true triaxial stress-chemical multi-field coupling accelerated corrosion device; inputting hydraulic pressure into the rigid sleeve through the peripheral hydraulic inlet; Oil is supplied to control the outer wall confining pressure P2 of the hollow cylindrical sample, and at the same time, an erosive solution is input into the hollow cylindrical sample through the first inner confining hydraulic inlet and the second inner confining hydraulic inlet to control the inner wall pressure P1 of the hollow cylindrical sample; after the P1 value and the P2 value are stable, the second accommodating area is filled with hydraulic oil through the lower hydraulic outlet, and then the first accommodating area is filled with hydraulic oil through the upper hydraulic inlet so that the partition block is pressurized to drive the loading rod to move downward, thereby applying a downward pressure F to the hollow cylindrical sample, and at the same time, the loading rod is rotated by the combined torque transmission mechanism to apply a torque M to the hollow cylindrical sample t ; The first strain gauge and the second strain gauge are used to test the deformation of the inside and outside of the hollow cylindrical specimen at different times, and the corresponding F value, P1 value, P2 value and torque M are recorded. t The value of is set to complete the test.

[0015] In the second aspect, after the test is completed, the filling of hydraulic oil into the first accommodating area is stopped, and then the hydraulic oil is filled into the second accommodating area to move the partition block upward to return to its original position, the liquid inside the rigid sleeve and the hollow cylinder is discharged, and the hollow cylindrical sample is taken out.

[0016] Beneficial effects:

[0017] In the present invention, the bottom base, the rigid sleeve and the top base constitute a confining pressure structure, a lower pressure head and an upper pressure head are arranged inside the confining pressure structure, the upper pressure head and the lower pressure head constitute a loading structure, a sample is loaded between the upper pressure head and the lower pressure head, and a space is provided between the loading structure and the confining pressure structure for filling hydraulic liquid, and an outer confining pressure P2 is given to the sample by the filling of hydraulic liquid. Since the outer part of the sample is covered with a heat shrink sleeve, the sample is prevented from being directly affected by the hydraulic liquid. The sample is in the shape of a hollow cylinder, and a space is provided inside the sample for filling the corrosive solution, and the corrosive solution gives the sample an inner confining pressure P1. The thickness of the hollow cylindrical sample is thinner, and relative to the conventional solid sample, the corrosive solution The erosion time is short, and the erosion damage of corrosive water environment to concrete can be quickly simulated, shortening the test time; the partition block is sealed and rotatably slidably connected to the top base, the loading rod is fixedly connected to the partition block, and the loading rod is pressed downward by the partition block to press the upper pressure head downward, giving the hollow cylindrical sample an upper downward pressure F; one end of the loading rod is connected to the upper pressure head through a concave-convex key, and the other end of the loading rod is fixedly connected to the torque loading mechanism, the torque loading mechanism gives a rotational torque, and the loading rod transmits the torque to the hollow cylindrical sample; in a true triaxial stress-chemical multi-field coupled accelerated erosion device of the present invention, the hollow cylindrical sample can be subjected to upper pressure F, outer confining pressure P2, inner confining pressure P1 and torque M t Four external loads, by controlling the upper pressure F, the outer confining pressure P2, the inner confining pressure P1 and the torque M t The magnitude of the four external loads can achieve a true triaxial stress state, which can be controlled by controlling the upper pressure F, the outer confining pressure P2, the inner confining pressure P1 and the torque M t Four external load paths realize the stress path of stress principal axis rotation; in summary, a true triaxial stress-chemical multi-field coupled accelerated corrosion testing device of the present invention combines the true triaxial stress test with the sample corrosion, simulates the coupling effect of the concrete structure in the true triaxial stress state and the corrosive water environment, accelerates the corrosion rate of the concrete by filling the corrosive solution inside the hollow cylindrical sample, shortens the corrosion time, and can quickly test the damage of the concrete under the stress-chemical corrosion coupling effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a structural schematic diagram of a true triaxial stress-chemical multi-field coupling accelerated erosion device of the present invention;

[0020] Figure 2 It is a structural schematic diagram of a concave-convex key in a true triaxial stress-chemical multi-field coupling accelerated erosion device of the present invention;

[0021] Figure 3 is a top view of the erosion of the hollow cylindrical specimen of the present invention;

[0022] Figure 4 This is the top view of the erosion of a conventional solid specimen;

[0023] Figure 5 It is a schematic diagram of the force on a hollow cylindrical specimen in a true triaxial stress-chemical multi-field coupled accelerated corrosion test of the present invention;

[0024] Figure 6 It is a schematic diagram of converting cylindrical coordinate system into rectangular coordinate system. Description of the drawings:

[0026] 1. Confining pressure structure; 11. Bottom base; 12. Rigid sleeve; 13. Top base;

[0027] 2. Loading structure; 21. Lower pressure head; 22. Upper pressure head;

[0028] 3. Hollow cylindrical specimen;

[0029] 4. Upper loading structure; 41. Upper pressure loading structure; 411. Loading rod; 412. Separating block; 42. Torque loading structure; 421. Axial loading piston; 422. Combined torque transmission mechanism;

[0030] 5. Sealing cover;

[0031] 6. Fixing bolts;

[0032] 7. Concave and convex keys;

[0033] 101, first inner hydraulic inlet; 102, first inner hydraulic outlet; 103, outer hydraulic inlet; 104, second inner hydraulic inlet; 105, second inner hydraulic outlet; 106, outer hydraulic outlet; 107, upper hydraulic inlet; 108, lower hydraulic outlet;

[0034] 201, a first data transmission channel; 202, a second data transmission channel; 203, a third data transmission channel. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0036] Embodiment 1

[0037] like Figure 1 As shown, the present embodiment 1 provides a true triaxial stress-chemical multi-field coupled accelerated corrosion test device, the true triaxial stress-chemical multi-field coupled accelerated corrosion test device comprises: a confining pressure structure 1, the confining pressure structure 1 comprises a bottom base 11, a rigid sleeve 12 and a top base 13, the rigid sleeve 12 is a cylindrical structure, one end of the rigid sleeve 12 is sealed and connected to the bottom base 11, the other end of the rigid sleeve 12 is sealed and connected to the top base 13, the center of the top base 11 is opened A first loading hole is provided; a loading structure 2, the loading structure 2 includes a lower pressure head 21 and an upper pressure head 22, one end of the lower pressure head 21 is fixed to the center of the bottom base 11, and the other end of the lower pressure head 21 is sealed and fixedly connected to one end of the hollow cylindrical sample 3; one end of the upper pressure head 22 is sealed and fixedly connected to the other end of the hollow cylindrical sample 3, and the outer sealing sleeve of the hollow cylindrical sample 3 is provided with a heat shrink sleeve; an upper loading structure 4, the upper loading system 4 includes an upper pressure loading structure 41 and A torque loading structure 42, wherein the upper pressure loading structure 41 comprises a loading rod 411 and a partition block 412, wherein the partition block 412 is sealed and rotatably connected to the top base 13, and a second loading hole is provided at the center of the partition block 412; a sealing cover 5, wherein the sealing cover 5 is located above the top base 13 and is fixedly and sealedly connected to the top base 13, and a third loading hole is provided in the middle of the sealing cover 5; a plurality of fixing bolts 6, wherein a plurality of fixing bolts 6 are fixedly connected to the bottom base 11 and the top base 13 along the periphery of the rigid sleeve 12; wherein one end of the loading rod 411 passes through the third loading hole, the second loading hole, and the first loading hole in sequence and is fixedly connected to the other end of the upper pressure head 22 through a concave-convex key 7, and the other end of the loading rod 411 is fixedly connected to the torque loading structure 42; the loading rod 411 is fixedly connected to the partition block 412, and the sealing cover 5 and the top base 13 are respectively sealed and rotatably connected to the loading rod 411.

[0038] In the present invention, the bottom base, the rigid sleeve and the top base constitute a confining pressure structure, a lower pressure head and an upper pressure head are arranged inside the confining pressure structure, the upper pressure head and the lower pressure head constitute a loading structure, a sample is loaded between the upper pressure head and the lower pressure head, and a space is provided between the loading structure and the confining pressure structure for filling hydraulic liquid, and an outer confining pressure P2 is given to the sample by the filling of hydraulic liquid. Since the outer part of the sample is covered with a heat shrink sleeve, the sample is prevented from being directly affected by the hydraulic liquid. The sample is in the shape of a hollow cylinder, and a space is provided inside the sample for filling the corrosive solution, and the corrosive solution gives the sample an inner confining pressure P1. The thickness of the hollow cylindrical sample is thinner, and relative to the conventional solid sample, the corrosive solution The erosion time is short, and the erosion damage of corrosive water environment to concrete can be quickly simulated, shortening the test time; the partition block is sealed and rotatably slidably connected to the top base, the loading rod is fixedly connected to the partition block, and the loading rod is pressed downward by the partition block to press the upper pressure head downward, giving the hollow cylindrical sample an upper downward pressure F; one end of the loading rod is connected to the upper pressure head through a concave-convex key, and the other end of the loading rod is fixedly connected to the torque loading mechanism, the torque loading mechanism gives a rotational torque, and the loading rod transmits the torque to the hollow cylindrical sample; in a true triaxial stress-chemical multi-field coupled accelerated erosion device of the present invention, the hollow cylindrical sample can be subjected to upper pressure F, outer confining pressure P2, inner confining pressure P1 and torque M t Four external loads, by controlling the upper pressure F, the outer confining pressure P2, the inner confining pressure P1 and the torque M t The magnitude of the four external loads can achieve a true triaxial stress state, which can be controlled by controlling the upper pressure F, the outer confining pressure P2, the inner confining pressure P1 and the torque M t Four external load paths realize the stress path of stress principal axis rotation; in summary, a true triaxial stress-chemical multi-field coupled accelerated corrosion testing device of the present invention combines the true triaxial stress test with the sample corrosion, simulates the coupling effect of the concrete structure in the true triaxial stress state and the corrosive water environment, accelerates the corrosion rate of the concrete by filling the corrosive solution inside the hollow cylindrical sample, shortens the corrosion time, and can quickly test the damage of the concrete under the stress-chemical corrosion coupling effect.

[0039] In some possible implementations, a support platform with a cylindrical structure is provided in the middle of the bottom base 11, the down-pressure head 21 is fixed at the center of the support platform, and the inner wall of one end of the rigid sleeve 12 is tightly attached to the side wall cover of the support platform and is arranged on the periphery of the support platform; a first inner hydraulic inlet 101, a first inner hydraulic outlet 102 and a peripheral hydraulic inlet 103 are provided on the support platform, and the first inner hydraulic inlet 101 is located at the center of the support platform.

[0040] Specifically, the bottom base is in a "convex" shape, and the protruding part is the support platform. The rigid sleeve is closely attached to the side wall cover of the support platform and is arranged on the periphery of the support platform, so that the rigid sleeve can be stably located at the center of the bottom base. At the same time, the rigid sleeve and the bottom base are sealed to avoid leakage when the hydraulic liquid is filled into the rigid sleeve; the first inner hydraulic inlet is used to input the corrosive liquid into the hollow cylindrical specimen, and the first inner hydraulic outlet is used for the hydraulic pipe to pass through. The first inner hydraulic outlet and the hydraulic pipe are sealed to avoid leakage of the hydraulic liquid in the rigid sleeve. The outer hydraulic inlet is used to input the hydraulic liquid into the rigid sleeve.

[0041] In some possible implementations, a lower support block with a cylindrical structure is provided in the middle of the upper part of the lower pressure head 21, and the inner wall of one end of the hollow cylindrical sample 3 is tightly attached to the side wall cover of the lower support block and is arranged on the periphery of the lower support block; a second inner hydraulic inlet 104 penetrating the lower pressure head is opened in the center of the lower support block, and the second inner hydraulic inlet 104 is communicated with the first inner hydraulic inlet 101, and the first inner hydraulic outlet 102 and the outer hydraulic inlet 103 are located on the outside of the bottom of the lower pressure head 21.

[0042] Specifically, the lower pressure head is in a "convex" shape, the protruding part is the lower support block, the interior of the hollow cylindrical sample is hollow, one end of the hollow cylindrical sample is sleeved on the outer periphery of the lower support block, the interior of the hollow cylinder and the lower pressure head are sealed to prevent leakage of the corrosive solution filled in the hollow cylinder; the second inner hydraulic inlet is connected to the first inner hydraulic inlet, and is used to input the corrosive solution into the interior of the hollow cylinder.

[0043] In some possible implementations, an upper support block with a cylindrical structure is provided in the middle of the lower part of the upper pressure head 22, and the inner wall of the other end of the hollow cylindrical sample 3 is tightly attached to the side wall cover of the upper support block and is arranged on the periphery of the upper support block; a second inner hydraulic outlet 105 penetrating the upper pressure head is opened on the upper support block, and the second inner hydraulic outlet 105 is sealed and connected to the first inner hydraulic outlet 102 through a hydraulic pipe.

[0044] Specifically, the upper pressure head is in an inverted "convex" shape, the protruding part is the upper support block, the inside of the hollow cylindrical sample is hollow, and the other end of the hollow cylindrical sample is sleeved on the outer periphery of the upper support block. The inside of the hollow cylinder and the upper pressure head are sealed to prevent leakage of the corrosive solution filled in the hollow cylinder; the second inner hydraulic outlet is sealed with the first inner hydraulic outlet through a hydraulic pipe to discharge the corrosive liquid.

[0045] In some possible implementations, the bottom of the top base 13 has a protruding closing cover, and the inner wall of the other end of the rigid sleeve 12 is tightly attached to the side wall cover of the closing cover and is arranged on the periphery of the closing cover; a peripheral hydraulic outlet 106 is opened on the closing cover; wherein a first loading hole is opened in the center of the closing cover, and the closing cover is sealed and rotatably slidably connected to the loading rod 411.

[0046] Specifically, the bottom of the bottom base is in an inverted "convex" shape, and the protruding part is a closing cover. The inner wall of the other end of the rigid sleeve is close to the side wall cover of the closing cover and is arranged on the periphery of the closing cover, so that the rigid sleeve can be stably located at the center of the top base. At the same time, the rigid sleeve and the top base are sealed to avoid leakage when the hydraulic liquid is filled into the rigid sleeve; the peripheral hydraulic outlet is used to discharge the hydraulic liquid inside the rigid sleeve; the closing cover and the loading rod are sealed and rotatably slidably connected, and the seal can avoid leakage of hydraulic liquid in the top space of the top base. The rotation facilitates the rotation of the loading rod under the action of the torque loading structure, and the sliding facilitates the loading rod to apply a loading force F downward to the hollow cylindrical sample.

[0047] In some possible implementations, the top of the top base 13 has a accommodating space, the dividing block 412 is located inside the accommodating space and divides the accommodating space into a first accommodating area and a second accommodating area, and the dividing block 412 is sealingly and slidably connected to the inner wall of the accommodating space; an upper hydraulic inlet 107 is opened on the side wall at the upper end of the first accommodating area, and a lower hydraulic outlet 108 is opened on the side wall at the lower end of the second accommodating area; wherein the sealing cover 5 covers the top end of the accommodating space and is fixedly and sealingly connected to the top of the top base 13.

[0048] Specifically, the accommodating space at the top of the top base is sealed by a sealing cover, and a partition block divides the accommodating space into two upper and lower non-communicating spaces inside the accommodating space. The partition block is sealingly and slidably connected to the inner wall of the accommodating space, so that the partition block can slide up and down inside the accommodating space. When hydraulic liquid is filled into the first accommodating area through the upper hydraulic inlet, the hydraulic liquid in the first accommodating area can be pressed out, and the partition block moves downward, driving the loading rod to move downward, giving the hollow cylindrical sample a downward force F.

[0049] In some possible implementations, the torque loading structure 42 includes: an axial loading piston 421, one end of which is fixedly connected to the other end of the loading rod 411; and a combined torque transmission mechanism 422, one end of which is fixedly connected to the combined torque transmission mechanism 422.

[0050] Specifically, the combined torque transmission mechanism rotates the axial loading piston, and then transmits the torque to the hollow cylindrical specimen through the loading rod.

[0051] In some possible implementations, the true triaxial stress-chemical multi-field coupled accelerated corrosion device also includes a strain testing structure, which includes: a first strain gauge, which is located in the internal space of the hollow cylindrical specimen 3; a second strain gauge, which is located inside the rigid sleeve 12; a first strain cable, one end of which is connected to the first strain gauge; a second strain cable, one end of which is connected to the second strain gauge; wherein a first data transmission channel 201 and a second data transmission channel 202 are further provided on the support platform, the first data transmission channel 201 and the second data transmission channel 202 are located on the outside of the lower pressure head 21, and a third data transmission channel 203 is further provided on the upper pressure head 22; the other end of the first strain cable passes through the second data transmission channel 202 and the third data transmission channel 203 in sequence to be connected to the first strain display; the other end of the second strain cable passes through the first data transmission channel 201 to be connected to the second strain display.

[0052] Specifically, the first strain gauge is used to test the strain inside the hollow cylinder, and the second strain gauge is used to test the strain outside the hollow cylindrical specimen, thereby obtaining the deformation of the hollow cylindrical specimen.

[0053] Embodiment 2

[0054] like Figures 1 to 6 As shown, the second embodiment of the present invention provides a true triaxial stress-chemical multi-field coupling accelerated corrosion test method, which is used for testing a true triaxial stress-chemical multi-field coupling accelerated corrosion device in the first embodiment. The true triaxial stress-chemical multi-field coupling accelerated corrosion test method specifically includes: preparing a hollow cylindrical sample, placing a first strain gauge inside the hollow cylindrical sample and connecting a cable, and then installing the hollow cylindrical sample in the true triaxial stress-chemical multi-field coupling accelerated corrosion device; inputting hydraulic oil into the rigid sleeve through the peripheral hydraulic inlet to control the hollow cylindrical sample to be The outer wall of the cylindrical sample is confined under pressure P2, and at the same time, an erosive solution is input into the interior of the hollow cylindrical sample through the first inner hydraulic inlet and the second inner hydraulic inlet to control the inner wall pressure P1 of the hollow cylindrical sample; after the P1 value and the P2 value are stable, the second accommodating area is filled with hydraulic oil through the lower hydraulic outlet, and then the first accommodating area is filled with hydraulic oil through the upper hydraulic inlet so that the partition block is pressurized to drive the loading rod to move downward, thereby applying a downward pressure F to the hollow cylindrical sample, and at the same time, the loading rod is rotated by the combined torque transmission mechanism to apply a torque M to the hollow cylindrical sample t; The first strain gauge and the second strain gauge are used to test the deformation of the inside and outside of the hollow cylindrical specimen at different times, and the corresponding F value, P1 value, P2 value and torque M are recorded. t value, the test is completed; after the test is completed, the filling of hydraulic oil into the first accommodating area is stopped, and then the hydraulic oil is filled into the second accommodating area to move the partition block upward to restore its original position, the liquid inside the rigid sleeve and the hollow cylinder is discharged, and the hollow cylindrical sample is taken out.

[0055] Specifically, in the second embodiment, a hollow cylindrical sample is used instead of a traditional solid cylindrical sample for test. The hollow cylindrical sample is a concrete sample. The sample height can be 100 mm, the outer diameter can be 50 mm, and the inner diameter can be 30 mm. During the test, the interior of the hollow cylindrical sample is filled with corrosive solution, the erosion surface is inside the hollow cylindrical sample, and the interior of the hollow cylindrical sample is exposed, which is convenient for the corrosive solution to erode. The composition of the corrosive solution is determined by the specific groundwater environment; the thickness of the hollow cylindrical sample is thin, which shortens the time when the sample is corroded and shortens the test time; the thickness of the hollow cylindrical sample is relatively small relative to the overall size of the concrete sample, and the hollow cylindrical sample can be regarded as a thin-walled cylindrical elastomer, and the force characteristics of the thin-walled cylindrical elastomer are used to realize the true triaxial stress state of the hollow cylindrical sample. Hydraulic oil is input into the rigid sleeve through the peripheral hydraulic inlet to fill the rigid sleeve with hydraulic oil, and the hydraulic oil is output through the peripheral hydraulic outlet to provide an external confining pressure P2 for the hollow cylindrical specimen. The interior of the hollow cylindrical specimen is filled with corrosive liquid, providing an internal pressure P1 for the hollow cylindrical specimen; the combined torque transmission mechanism rotates the axial loading piston to transmit the torque to the specimen through the loading rod; Figure 5 As shown in the figure, P1 is the internal pressure of the sample, P2 is the external confining pressure of the sample, and M t is the torque on the sample, F is the upper pressure on the sample, and a small piece of it is analyzed to establish a cylindrical coordinate system. For example, when the external confining pressure P2 on the sample is greater than the internal pressure P1 of the sample, the normal stress σ inside the sample can be obtained through elastic mechanics analysis. r , σ θ and σ2, σ r and σ θ They are controlled by P2 and P1 respectively, σ2 is controlled by the upper pressure F, and there is also a shear stress τ Zθ , given by the torque M t Then, by simple coordinate transformation, the cylindrical coordinate system is transformed into the rectangular coordinate system, and the principal stresses σ1, σ2 and σ 3, and its direction, such as Figure 6 Therefore, we can control P1, P2, M tand F, to realize the stress path of stress principal axis rotation (controlling angle α). The deformation inside and outside the specimen is tested by the first strain gauge and the second strain gauge respectively. The deterioration and damage of the specimen under the coupling of true triaxial stress and chemical corrosion can be studied by combining the force and deformation of the specimen.

[0056] It should be noted that the true triaxial stress-chemical multi-field coupling accelerated corrosion test method in the second embodiment is used for testing the true triaxial stress-chemical multi-field coupling accelerated corrosion device in the first embodiment. Therefore, the performance principle of the true triaxial stress-chemical multi-field coupling accelerated corrosion device will not be repeated here. For the undetailed parts, please refer to the first embodiment.

[0057] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A true triaxial stress-chemical multi-field coupled accelerated corrosion test device, characterized in that: The true triaxial stress-chemical multi-field coupling accelerated corrosion testing device comprises: A confining and pressing structure (1), the confining and pressing structure (1) comprising a bottom base (11), a rigid sleeve (12) and a top base (13), the rigid sleeve (12) being a cylindrical structure, one end of the rigid sleeve (12) being sealedly connected to the bottom base (11), the other end of the rigid sleeve (12) being sealedly connected to the top base (13), and a first loading hole being provided at the center of the top base (11); A loading structure (2), the loading structure (2) comprising a lower pressure head (21) and an upper pressure head (22), one end of the lower pressure head (21) being fixed at the center of the bottom base (11), and the other end of the lower pressure head (21) being sealed and fixedly connected to one end of the hollow cylindrical sample (3); one end of the upper pressure head (22) being sealed and fixedly connected to the other end of the hollow cylindrical sample (3), and an outer sealing sleeve of the hollow cylindrical sample (3) being provided with a heat shrink sleeve; An upper loading structure (4), the upper loading system (4) comprising an upper pressure loading structure (41) and a torque loading structure (42), the upper pressure loading structure (41) comprising a loading rod (411) and a spacer block (412), the spacer block (412) being rotatably and slidably connected to the top base (13) in a sealed manner, and a second loading hole being provided at the center of the spacer block (412); a sealing cover (5), the sealing cover (5) being located above the top base (13) and being fixedly sealed and connected to the top base (13), and a third loading hole being provided in the middle of the sealing cover (5); A plurality of fixing bolts (6), wherein the plurality of fixing bolts (6) are arranged along the periphery of the rigid sleeve (12) to fix the bottom base (11) and the top base (13) together; Among them, one end of the loading rod (411) passes through the third loading hole, the second loading hole, and the first loading hole in sequence, and is fixedly connected to the other end of the upper pressure head (22) through a concave-convex key (7), and the other end of the loading rod (411) is fixedly connected to the torque loading structure (42); the loading rod (411) is fixedly connected to the partition block (412), and the sealing cover (5) and the top base (13) are respectively sealed and rotatably slidably connected to the loading rod (411).

2. A true triaxial stress-chemical multi-field coupled accelerated corrosion testing device as claimed in claim 1, characterized in that: A support platform with a cylindrical structure is provided in the middle of the bottom base (11), the lower pressure head (21) is fixed at the center of the support platform, and the inner wall of one end of the rigid sleeve (12) is tightly attached to the side wall cover of the support platform and is arranged on the periphery of the support platform; a first inner hydraulic inlet (101), a first inner hydraulic outlet (102) and an outer hydraulic inlet (103) are provided on the support platform, and the first inner hydraulic inlet (101) is located at the center of the support platform.

3. A true triaxial stress-chemical multi-field coupled accelerated corrosion testing device as claimed in claim 2, characterized in that: A lower support block with a cylindrical structure is provided in the middle of the upper part of the lower pressure head (21); the inner wall of one end of the hollow cylindrical sample (3) is tightly attached to the side wall cover of the lower support block and is arranged on the periphery of the lower support block; a second inner hydraulic inlet (104) penetrating the lower pressure head is provided at the center of the lower support block; the second inner hydraulic inlet (104) is communicated with the first inner hydraulic inlet (101); the first inner hydraulic outlet (102) and the outer hydraulic inlet (103) are located on the outer side of the bottom of the lower pressure head (21).

4. A true triaxial stress-chemical multi-field coupled accelerated corrosion testing device as claimed in claim 3, characterized in that: An upper support block with a cylindrical structure is provided in the middle of the lower part of the upper pressure head (22), and the inner wall of the other end of the hollow cylindrical sample (3) is tightly attached to the side wall cover of the upper support block and is arranged on the periphery of the upper support block; a second inner hydraulic outlet (105) penetrating the upper pressure head is provided on the upper support block, and the second inner hydraulic outlet (105) is sealed and connected to the first inner hydraulic outlet (102) through a hydraulic pipe.

5. A true triaxial stress-chemical multi-field coupled accelerated corrosion testing device as claimed in claim 4, characterized in that: The bottom of the top base (13) has a protruding closing cover, and the inner side wall of the other end of the rigid sleeve (12) is tightly attached to the side wall cover of the closing cover and is arranged on the periphery of the closing cover; the closing cover is provided with a peripheral hydraulic outlet (106); wherein a first loading hole is provided at the center of the closing cover, and the closing cover is sealed and rotatably slidably connected to the loading rod (411).

6. A true triaxial stress-chemical multi-field coupled accelerated corrosion testing device as claimed in claim 5, characterized in that: The top of the top base (13) has a accommodating space, the dividing block (412) is located inside the accommodating space and divides the accommodating space into a first accommodating area and a second accommodating area, and the dividing block (412) is sealingly and slidably connected to the inner wall of the accommodating space; an upper hydraulic inlet (107) is opened on the side wall at the upper end of the first accommodating area, and a lower hydraulic outlet (108) is opened on the side wall at the lower end of the second accommodating area; wherein the sealing cover (5) covers the top end of the accommodating space and is fixedly and sealingly connected to the top of the top base (13).

7. A true triaxial stress-chemical multi-field coupled accelerated corrosion testing device as claimed in claim 6, characterized in that: The torque loading structure (42) comprises: An axial loading piston (421), one end of which is fixedly connected to the other end of the loading rod (411); A combined torque transmission mechanism (422), one end of the axial loading piston (421) being fixedly connected to the combined torque transmission mechanism (422).

8. A true triaxial stress-chemical multi-field coupled accelerated corrosion testing device as claimed in claim 7, characterized in that: The true triaxial stress-chemical multi-field coupling accelerated corrosion device also includes a strain test structure, and the strain test structure includes: a first strain gauge, the first strain gauge being located in the inner space of the hollow cylindrical specimen (3); a second strain gauge, the second strain gauge being located inside the rigid sleeve (12); a first strain cable, one end of which is connected to the first strain gauge; a second strain cable, one end of the second strain cable being connected to the second strain gauge; The support platform is further provided with a first data transmission channel (201) and a second data transmission channel (202), the first data transmission channel (201) and the second data transmission channel (202) are located outside the lower pressing head (21), and the upper pressing head (22) is further provided with a third data transmission channel (203); the other end of the first strain cable (83) passes through the second data transmission channel (202) and the third data transmission channel (203) in sequence to be connected to the first strain display; the other end of the second strain cable (84) passes through the first data transmission channel (201) to be connected to the second strain display.

9. A true triaxial stress-chemical multi-field coupled accelerated corrosion test method, used for testing a true triaxial stress-chemical multi-field coupled accelerated corrosion test device as claimed in any one of claims 1 to 8, characterized in that: The true triaxial stress-chemical multi-field coupling accelerated corrosion test method specifically includes: A hollow cylindrical sample is manufactured, a first strain gauge is placed inside the hollow cylindrical sample and a cable is connected, and then the hollow cylindrical sample is installed in a true triaxial stress-chemical multi-field coupling accelerated erosion device; Hydraulic oil is input into the rigid sleeve through the outer hydraulic inlet to control the outer wall pressure P2 of the hollow cylindrical sample, and at the same time, an aggressive solution is input into the hollow cylindrical sample through the first inner hydraulic inlet and the second inner hydraulic inlet to control the inner wall pressure P1 of the hollow cylindrical sample; After the P1 value and the P2 value are stable, the second accommodating area is filled with hydraulic oil through the lower hydraulic outlet, and then the first accommodating area is filled with hydraulic oil through the upper hydraulic inlet, so that the partition block is pressed to drive the loading rod to move downward, thereby applying a downward pressure F to the hollow cylindrical specimen, and at the same time, the loading rod is rotated by the combined torque transmission mechanism to apply a torque M to the hollow cylindrical specimen. t ; The first strain gauge and the second strain gauge are used to test the deformation of the inside and outside of the hollow cylindrical specimen at different times, and the corresponding F, P1 value, P2 value and torque M are recorded. t The value of is set to complete the test.

10. A true triaxial stress-chemical multi-field coupled accelerated corrosion testing method as claimed in claim 9, characterized in that: After the test is completed, the filling of hydraulic oil into the first accommodating area is stopped, and then the hydraulic oil is filled into the second accommodating area to move the partition block upward to restore the original position, the liquid inside the rigid sleeve and the hollow cylinder is discharged, and the hollow cylindrical sample is taken out.

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