CN111896454A - Concrete water-resistant permeability test device and test method - Google Patents

Abstract

The embodiment of the application provides a concrete water permeability resistance test device and test method for to having the cylindrical concrete sample of water injection chamber carry out water permeability resistance test, concrete water permeability resistance test device includes: a hydraulic loading device and an external load loading device; the hydraulic loading device comprises an automatic pressurizing machine, a first cover plate assembly and a second cover plate assembly, wherein the first cover plate assembly and the second cover plate assembly are hermetically connected with two ends of a concrete test piece; the external load loading device comprises a first clamping plate, a second clamping plate, a guide piece, a pushing mechanism, a mounting plate and a displacement sensor; the first clamping plate is fixedly connected with the guide piece, and the second clamping plate is connected with the guide piece in a sliding manner; the mounting panel and guide fixed connection, the pushing mechanism is installed on the mounting panel. The concrete water permeability resistance test device and the test method provided by the embodiment of the application can be used for efficiently and accurately testing and evaluating the water pressure resistance permeability of the concrete lining of the tunnel under the action of an external load.

Description

Concrete water-resistant permeability test device and test method

Technical Field

The invention relates to the field of concrete water-resistant permeability tests, in particular to a concrete water-resistant permeability test device and a concrete water-resistant permeability test method.

Background

The current concrete water permeability resistance test is based on Darcy's law of hydrodynamics, and takes concrete as a porous solid material, and uses permeability coefficient to evaluate the impermeability of concrete, which is called permeability coefficient method. The permeability coefficient method is a method for studying the permeability of concrete by using the principle that fluid gradually permeates from one end to the other end through the pores of a measured object under a certain pressure condition. In China, in order to consider the convenience of practical engineering application, a qualitative impermeability labeling method is mainly adopted to evaluate the impermeability of concrete. Specifically, 6 standard anti-permeability test pieces (the upper bottom surface is 175mm, and the lower bottom surface is 185mm) are manufactured according to the specification requirements, after the side surfaces of the anti-permeability test pieces are sealed, the anti-permeability test pieces are arranged on an anti-permeability testing machine to be pressurized step by step, the water pressure of each step is stabilized for 8 hours until three of six test pieces generate leakage, and the anti-permeability grade of the anti-permeability test pieces is calibrated according to the water pressure during leakage. In addition, a water seepage height method and a relative permeability coefficient method can be adopted, the test method is similar to the impervious label method, and the similar relative permeability coefficient can be directly or indirectly expressed.

However, the related test method cannot perform efficient and accurate test and evaluation on the hydraulic pressure permeation resistance of the concrete lining of the tunnel under the action of an external load.

Disclosure of Invention

In view of the above, the main object of the embodiments of the present application is to provide a concrete water permeation resistance testing apparatus and a testing method, which can perform efficient and accurate test and evaluation on the water permeation resistance of a concrete lining of a tunnel under an external load.

In order to achieve the above purpose, the technical solution of the embodiment of the present application is implemented as follows:

an embodiment of the application provides a concrete water permeability resistance test device for carry out water permeability resistance test to columniform concrete sample, the concrete sample has and runs through along the axial the water injection chamber of concrete sample includes:

the hydraulic loading device comprises an automatic pressurizing machine, a first cover plate assembly and a second cover plate assembly, wherein the first cover plate assembly and the second cover plate assembly are respectively connected with two ends of the concrete test piece in a sealing mode, and the first cover plate assembly is provided with a water injection channel used for communicating the automatic pressurizing machine with the water injection cavity;

the external load loading device comprises a first clamping plate, a second clamping plate, a guide piece, a pushing mechanism, a mounting plate and a displacement sensor; the first clamping plate is fixedly connected with the guide piece, the second clamping plate is connected with the guide piece in a sliding mode, and the first clamping plate and the second clamping plate are used for clamping the concrete specimen from two radial sides of the concrete specimen; the mounting plate is fixedly connected with the guide piece and is positioned on one side, far away from the first clamping plate, of the second clamping plate, the pushing mechanism is mounted on the mounting plate, and the telescopic pushing part of the pushing mechanism faces towards the second clamping plate; the displacement sensor is connected with the first clamping plate and the second clamping plate and used for detecting the displacement of the second clamping plate in the process that the pushing mechanism pushes the second clamping plate.

In one embodiment, the first cover plate assembly includes a first cover plate having the water filling channel, and a first sealing ring provided at one side of the first cover plate, the first sealing ring being located at a circumferential side of a water outlet of the water filling channel; the first sealing ring is used for being in sealing contact with the end face of one end of the concrete test piece;

the second cover plate assembly comprises a second cover plate and a second sealing ring arranged on one side of the second cover plate; and the second sealing ring is used for being in sealing contact with the end face of the other end of the concrete test piece.

In one embodiment, one side of the first cover plate is provided with a first positioning groove used for being matched with one end of the concrete sample, the water injection channel is communicated with the first positioning groove, and the first sealing ring is arranged in the first positioning groove;

one side of the second cover plate is provided with a second positioning groove used for being matched with the other end of the concrete test piece, and the second sealing ring is arranged in the second positioning groove.

In one embodiment, the first cover plate assembly comprises a first cover plate, the water inlet of the water injection channel is arranged on the side wall of the first cover plate, and the water outlet of the water injection channel is arranged on the end surface of one side of the first cover plate.

In one embodiment, the water injection channel comprises a threaded connection section and an extension section communicated with one end of the threaded connection section, the opening at one end of the extension section, away from the threaded connection section, is the water inlet, and the opening at one end of the extension section, away from the threaded connection section, is the water outlet.

In one embodiment, the first cover plate assembly is securely connected to the second cover plate assembly.

In one embodiment, a portion of the structure of the second clamping plate projects outwardly to form an abutment boss; when the concrete test piece is clamped between the first clamping plate and the second clamping plate, the abutting lug boss abuts against the concrete test piece.

In one embodiment, the guide member is a pull rod, and the first clamping plate and the second clamping plate are both arranged on the pull rod in a penetrating manner.

In one embodiment, the number of the pull rods is two, the two pull rods are arranged in parallel at intervals, and a test piece accommodating space is formed between the two pull rods;

one of the two pull rods penetrates through one end of the first clamping plate and one end of the second clamping plate, and the other of the two pull rods penetrates through the other end of the first clamping plate and the other end of the second clamping plate.

In one embodiment, two of the pull rods are arranged in parallel at intervals in the vertical direction, the first cover plate assembly comprises a first cover plate, the first cover plate is provided with a first loading avoiding port and a second loading avoiding port, and the second cover plate is provided with a third loading avoiding port and a fourth loading avoiding port;

the concrete sample is held between the first clamping plate and the second clamping plate, the two ends of the water injection cavity are respectively connected with the first cover plate assembly and the second cover plate assembly in a sealing mode, the first loading is used for avoiding the port and the third loading is used for avoiding the port and the first clamping plate, the second loading is used for avoiding the port and the fourth loading is used for avoiding the port and the second clamping plate.

Another embodiment of the present application further provides a method for testing water permeability resistance of concrete, which is implemented by using the apparatus for testing water permeability resistance of concrete, and the method includes the following steps:

dividing a plurality of cylindrical concrete test pieces with water injection cavities into three groups, wherein the three groups of concrete test pieces are respectively a first group of test pieces, a second group of test pieces and a third group of test pieces, the concrete test piece in the first group of test pieces is a concrete test piece I, the concrete test piece in the second group of test pieces is a concrete test piece II, and the concrete test piece in the third group of test pieces is a concrete test piece III;

the first cover plate assembly and the second cover plate assembly are respectively connected with two ends of the water injection cavity of the concrete test piece I in a sealing mode; loading water reaching a preset water pressure into the water injection cavity of the first concrete test piece by using the automatic pressurizing machine until the water seeps out of the outer side wall of the first concrete test piece; obtaining the change rule of the concrete permeability coefficient under the stress-free action according to the loading data recorded by the automatic pressurizing machine in the water pressure loading process; the loading data comprises loading water quantities corresponding to different time points of the automatic pressurizing machine in a hydraulic loading process;

clamping the second concrete sample between the first clamping plate and the second clamping plate, and pushing the second clamping plate by using the pushing mechanism until the second concrete sample is subjected to bending damage; recording the magnitude of the top thrust loaded by the pushing mechanism in the process of pushing the second splint by the pushing mechanism, and recording the displacement of the second splint under the action of the top thrusts with different magnitudes, obtaining the change rule of the elastic modulus under the action of no water pressure according to the obtained top thrust loaded by the pushing mechanism and the corresponding displacement of the second splint, and determining the peak value of the top thrust loaded by the pushing mechanism;

the two ends of the water injection cavity of the concrete sample III are respectively in sealing connection with the first cover plate assembly and the second cover plate assembly, and the sealed concrete sample III is clamped between the first clamping plate and the second clamping plate; within a preset time, loading water reaching a preset water pressure into the water injection cavity of the concrete sample III by using the automatic pressurizing machine, and pushing the second clamping plate by using the pushing mechanism, wherein the maximum value of the top thrust loaded by the pushing mechanism is smaller than the peak value of the top thrust loaded by the pushing mechanism obtained in the test of the concrete sample II; obtaining the change rule of the concrete permeability coefficient under the action of an external load according to the loading data recorded in the water pressure loading process of the automatic pressurizing machine; the loading data comprises loading water quantities corresponding to different time points of the automatic pressurizing machine in a hydraulic loading process;

and comparing the obtained change rule of the concrete permeability coefficient under the action of the external load with the change rule of the concrete permeability coefficient under the action of the unstressed load to determine the influence of the mechanical damage of the concrete on the concrete permeability under the action of the external load.

The embodiment of the application provides a concrete water resistance permeability test device and a test method, and the water resistance permeability test is carried out on a cylindrical concrete test piece with a water injection cavity by utilizing a water pressure loading device and an external load loading device, so that the water resistance permeability of a concrete lining of a tunnel under the action of different external loads and water pressure can be analyzed, and then the water resistance permeability of the concrete lining of the tunnel under the action of the external loads can be tested and evaluated efficiently and accurately.

Drawings

FIG. 1 is a front view of a concrete water permeability resistance testing apparatus according to an embodiment of the present disclosure, in which a concrete sample is shown, and a part of a bolt connecting a first clamping plate and a second clamping plate is omitted to show a fit relationship between the first clamping plate and the concrete sample;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a left side view of FIG. 1;

FIG. 4 is a schematic view of the connection relationship between the first cover plate assembly and the second cover plate assembly shown in FIG. 1 and a concrete sample;

FIG. 5 is a schematic view of the first cleat shown in FIG. 1;

FIG. 6 is a schematic view of the second cleat shown in FIG. 1;

FIG. 7 is a schematic structural view of the first cover plate assembly shown in FIG. 1;

FIG. 8 is a sectional view taken along line A-A of FIG. 7;

FIG. 9 is a schematic structural view of the second cover plate assembly shown in FIG. 1;

FIG. 10 is a cross-sectional view taken along line B-B of FIG. 9;

fig. 11 is a flowchart of a method for testing water permeability resistance of concrete according to an embodiment of the present disclosure.

Reference numerals:

a concrete water permeability resistance test device 100; a hydraulic loading device 110; a first cover plate assembly 111; a first cover 1111; a first positioning groove 1111 a; a first load avoidance port 1111 b; a second load avoidance port 1111 c; a first seal ring 1112; a water injection passage 111 a; a water inlet 111 b; a water outlet 111 c; a threaded connection section 111 d; an extension section 111 e; a second cover plate assembly 112; a second cover plate 1121; a second positioning groove 1121 a; a third load avoidance port 1121 b; a fourth load avoidance port 1121 c; a second seal 1122; a bolt 113; an external load loading device 120; a first clamp plate 121; a second clamping plate 122; an abutment boss 1221; the guide 123; an urging mechanism 124; a telescopic ejector 1241; a mounting plate 125; a concrete sample 200; water injection cavity 200 a.

Detailed Description

It should be noted that, in the present application, technical features in examples and embodiments may be combined with each other without conflict, and the detailed description in the specific embodiment should be understood as an explanation of the gist of the present application and should not be construed as an improper limitation to the present application.

In the description of the present application, a "vertical direction" orientation or positional relationship is based on the orientation or positional relationship shown in fig. 1, it being understood that these orientation terms are merely for convenience in describing the present application and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be considered as limiting the present application.

An embodiment of the present application provides a concrete water permeability resistance test device 100 for to cylindrical concrete test piece 200 carry out water permeability resistance test, please refer to fig. 1 to 4, concrete test piece 200 has along the axial water injection chamber 200a that runs through concrete test piece 200, concrete water permeability resistance test device 100 includes: a hydraulic loading unit 110 and an external load loading unit 120.

The hydraulic loading apparatus 110 includes an automatic pressurizing machine (not shown), and a first cover plate assembly 111 and a second cover plate assembly 112 for sealing connection with both ends of the concrete specimen 200, respectively, the first cover plate assembly 111 having a water injection passage 111a for communicating the automatic pressurizing machine and the water injection chamber 200 a. That is, after the first and second cover assemblies 111 and 112 are hermetically connected to both ends of the water filling chamber 200a, respectively, the automatic pressurizing machine may load water into the water filling chamber 200a through the water filling passage 111 a.

The external load loading device 120 includes a first clamping plate 121, a second clamping plate 122, a guide 123, an ejector mechanism 124, a mounting plate 125, and a displacement sensor (not shown). The first clamping plate 121 is fixedly connected with the guide member 123, the second clamping plate 122 is slidably connected with the guide member 123, and the first clamping plate 121 and the second clamping plate 122 are used for clamping the concrete specimen 200 from two sides in the radial direction of the concrete specimen 200. The mounting plate 125 is fixedly connected to the guide 123 and located on a side of the second clamping plate 122 away from the first clamping plate 121, the pushing mechanism 124 is mounted on the mounting plate 125, and a telescopic pushing portion of the pushing mechanism 124 faces the second clamping plate 122, that is, when the concrete specimen 200 is clamped between the first clamping plate 121 and the second clamping plate 122, the pushing mechanism 124 can enable the first clamping plate 121 and the second clamping plate 122 to apply a radial pressure P to the concrete specimen 200 by pushing the second clamping plate 122, that is, the pushing mechanism 124 can load the external load on the concrete specimen 200. The displacement sensor is connected to the first clamping plate 121 and the second clamping plate 122, and is configured to detect a displacement of the second clamping plate 122 in a process of pushing the second clamping plate 122 by the pushing mechanism 124.

Specifically, the geometric dimensions of the cylindrical concrete sample 200 selected in the embodiment are 75mm in inner diameter, 150mm in outer diameter and 150mm in height, and in other embodiments, the geometric dimensions of the concrete sample 200 may be adjusted as needed.

The automatic pressurizing machine can keep the water pressure at the preset water pressure when water is loaded into the water injection cavity 200a of the concrete test piece 200, so that the influence on the test result caused by the fact that the water pressure in the water injection cavity 200a is reduced in the process of permeating into the side wall of the concrete test piece 200 is avoided, specifically, the automatic pressurizing machine of the embodiment can load and stabilize the water pressure within the range of 0-15MPa, and in addition, the automatic pressurizing machine can automatically record the loading water amounts corresponding to different time points in the water pressure loading process, so that the test data can be collected.

The pushing mechanism 124 may be a jack, a hydraulic cylinder, or other mechanism with a pushing function. In this embodiment, the guide 123 and mounting plate 125 are designed to meet the strength requirements of the highest load of 30 t.

The concrete water permeability resistance test described in this embodiment is to simplify the loading mode used in the test according to the loading mode of the tunnel. Specifically, the load to which the concrete lining of the tunnel is subjected is mainly divided into three parts: the pressure of the soil is obtained by multiplying the vertical pressure by a lateral pressure coefficient which is less than 1, wherein the lateral pressure coefficient is different but less than 1 for different formation conditions. In addition, the deformation of the stratum structure can be restrained by lateral soil pressure, the stress on the structure is actually beneficial, and the concrete water permeability resistance test described in the embodiment mainly considers the adverse effect of external load on the permeability of the concrete lining, so that the horizontal pressure can be ignored. The base reaction force is composed of vertical pressure and self-weight of the structure, and therefore, in the vertical pressure, the horizontal pressure and the base reaction force which are applied to the concrete lining, the vertical pressure is the main part of external load applied to the concrete lining, and is also the main factor which causes the concrete lining to crack and damage in the using process of the tunnel.

Referring to fig. 1, in order to ensure high efficiency and economy of the testing process, the horizontal load on the concrete lining is ignored in the concrete water permeability resistance test described in this embodiment, and a set of radial pressure P is used to simulate the load characteristic of the concrete lining in the vertical direction, specifically, the first clamping plate 121 fixedly connected to the guide member 123 can stop the concrete sample 200 from moving when the pushing mechanism 124 pushes the second clamping plate 122, so that the first clamping plate 121 and the second clamping plate 122 can apply the radial pressure P to the concrete sample 200, and further, the load characteristic of the concrete lining in the vertical direction can be simulated.

For the traditional test methods such as a permeability coefficient method, an anti-permeability label method and the like, the method mainly has the following obvious limitations:

1. the traditional test method is to adopt a solid cylindrical test piece to carry out a penetration test, water penetrates upwards from the bottom of the solid cylindrical test piece, namely the penetration surface of the solid cylindrical test piece is the bottom surface of the solid cylindrical test piece, the penetration depth of the solid cylindrical test piece is measured in the penetration process, and the penetration coefficient is calculated by using the penetration depth. In addition, the test result has larger error under the influence of the hydration process of the concrete;

2. the traditional test method needs to measure the penetration height of water through a ruler, when the water seepage amount is small, the penetration height of water is very small, and a large error is caused when the water seepage amount is measured by the ruler;

3. the traditional test method measures the water seepage amount of the concrete in the final state by splitting a test piece and the like, but the test method cannot obtain the change relation between the water seepage amount and time and cannot reflect the change rule of the permeability of the concrete along with the time, so the conclusion obtained by adopting the traditional test method has certain limitation;

4. because the tensile strength of the concrete is extremely low, the concrete is usually in a working state with cracks in the actual service process of the material, and the cracks can become main channels for water to permeate into the concrete under the action of external water pressure. The traditional test method cannot consider the crack phenomenon of the concrete material in the actual working process, so that the concrete permeability suitable for the actual engineering durability evaluation cannot be measured.

As for the concrete water permeability resistance test device 100 of the present embodiment, firstly, the water pressure loading device 110 of the present embodiment loads water into the water injection cavity 200a of the concrete sample 200, that is, the water permeates from the inner wall of the water injection cavity 200a, compared with the method of permeating water from the bottom of the solid cylindrical sample to the top in the conventional test method, the test device of the present embodiment changes the permeation direction of the concrete sample 200 from the original permeation from the bottom to the top to the inside according to the principle that the water pressure is equal in all directions, thereby increasing the hydraulic gradient in the concrete sample 200. Simultaneously, because the infiltration face of concrete sample 200 is changed into radial side by the bottom surface, so, the test device of this embodiment not only can greatly improve infiltration efficiency, avoids concrete sample 200 to receive the influence of hydration process, can also guarantee to observe obvious infiltration phenomenon from concrete sample 200's outer wall, and the accuracy of test result is higher. In addition, in the conventional test method, because the penetration direction of the solid cylindrical test piece is from bottom to top, a large amount of sealing needs to be performed on the side surface of the solid cylindrical test piece, the sealing workload is large, and the test failure is often caused by the water leakage phenomenon. In this embodiment, the first cover plate assembly 111 and the second cover plate assembly 112 only need to be sealed with the two ends of the water injection cavity 200a, so that the usage amount of the sealing material can be reduced, the sealing difficulty can be effectively reduced, and the possibility of water leakage caused by insufficient sealing measures can be reduced.

Secondly, because the automatic pressurizing machine can automatically record the loading water volume corresponding to different time points in the water pressure loading process, and the loading water volume is actually equivalent to the water seepage volume of the concrete test piece 200, when the water seepage volume of the concrete test piece 200 is small, the water seepage volume of the concrete test piece 200 can be obtained according to the loading water volume recorded by the automatic pressurizing machine, the water seepage volume can be obtained simply and conveniently, and the measuring precision of the water seepage volume can be ensured. In addition, according to the loading water amount corresponding to different time points automatically recorded by the automatic pressurizing machine, the change relation between the water seepage amount and the time can be obtained, and the change rule of the concrete permeability along with the time can be further reflected.

Finally, since the external load loading device 120 of the present embodiment can apply a radial pressure P to the concrete sample 200 to simulate the load characteristics of the concrete lining in the vertical direction, the testing device of the present embodiment can simulate the crack phenomenon generated in the actual working process of the concrete material, and further, the concrete permeability suitable for the actual engineering durability evaluation can be measured.

Therefore, by adopting the concrete water-resistant permeability test device 100 of the embodiment, the water-resistant permeability of the concrete lining of the tunnel under the action of different external loads and water pressure can be analyzed, and then the water-resistant permeability of the concrete lining of the tunnel under the action of the external loads can be efficiently and accurately tested and evaluated.

Referring to fig. 1, 4, and 7 to 10, in the present embodiment, the first cover plate assembly 111 includes a first cover plate 1111 having a water filling channel 111a, and a first sealing ring 1112 disposed at one side of the first cover plate 1111, and the first sealing ring 1112 is located at a peripheral side of a water outlet 111c of the water filling channel 111 a. The first seal 1112 is adapted to sealingly contact an end face of one end of the concrete specimen 200. Second cover plate 1121 the second cover plate assembly 112 includes a second cover plate 1121 and a second sealing ring 1122 provided on one side of the second cover plate 1121. The second seal 1122 is adapted to sealingly contact the end face of the other end of the concrete sample 200.

Specifically, when the first cover plate assembly 111 and the second cover plate assembly 112 are respectively connected to two ends of the concrete sample 200 in a sealing manner, the first sealing ring 1112 is sandwiched between the first cover plate 1111 and the end surface of one end of the concrete sample 200, the water outlet 111c of the water injection channel 111a is communicated with the water injection cavity 200a, and the second sealing ring 1122 is sandwiched between the second cover plate 1121 and the end surface of the other end of the concrete sample 200, so that the water injection cavity 200a can be well sealed. Since the inner diameter of the cylindrical concrete sample 200 selected in this embodiment is 75mm, the first seal ring 1112 and the second seal ring 1122 may be full-circle seal rubber rings with an inner diameter of 75mm and a wire diameter of 3mm, or seal rings with other specifications may be selected in other embodiments as long as the water injection cavity 200a can be sealed.

Further, referring to fig. 4 and 7 to 10, in the present embodiment, one side of the first cover plate 1111 is provided with a first positioning groove 1111a for being matched with one end of the concrete sample 200, the water injection channel 111a is communicated with the first positioning groove 1111a, and the first sealing ring 1112 is disposed in the first positioning groove 1111 a. One side of the second cover plate 1121 is provided with a second positioning groove 1121a for fitting with the other end of the concrete specimen 200, and a second sealing ring 1122 is disposed in the second positioning groove 1121 a. That is to say, when the first cover plate assembly 111 and the second cover plate assembly 112 are respectively connected with the two ends of the water injection cavity 200a in a sealing manner, one end of the concrete specimen 200 is located in the first positioning groove 1111a, the other end of the concrete specimen 200 is located in the second positioning groove 1121a, and the first positioning groove 1111a and the second positioning groove 1121a are arranged to perform a positioning function on the concrete specimen 200 and improve a sealing effect.

It is understood that in other embodiments, only the first positioning slot 1111a is disposed on the first cover 1111, and the second positioning slot 1121a is not disposed on the second cover 1121, or only the second positioning slot 1121a is disposed on the second cover 1121, and the first positioning slot 1111a is not disposed on the first cover 1111, or the first positioning slot 1111a is not disposed on the first cover 1111, and the second positioning slot 1121a is not disposed on the second cover 1121. In other embodiments, the first cover plate assembly 111 and the second cover plate assembly 112 may be sealed to both ends of the water injection chamber 200a in other manners as long as sealing of both ends of the water injection chamber 200a is ensured.

In addition, in the testing process, in order to prevent the first cover plate assembly 111 and the second cover plate assembly 112 from being loosened and causing sealing failure, after the first cover plate assembly 111 and the second cover plate assembly 112 are respectively connected to the two ends of the water injection cavity 200a in a sealing manner, the first cover plate assembly 111 and the second cover plate assembly 112 may be further fastened, for example, referring to fig. 1 to 3, in this embodiment, 6 bolts 113 are used to fasten the first cover plate 1111 and the second cover plate 1121, the specification of the bolts 113 may be M16 × 200, and in other embodiments, the number and the specification of the bolts 113 may be adjusted as needed. In other embodiments, the first cover plate assembly 111 and the second cover plate assembly 112 may not be fastened together.

Referring to fig. 1, 3, 4, 7 and 8, in the present embodiment, the water inlet 111b of the water filling channel 111a is disposed on the side wall of the first cover 1111, and the water outlet 111c of the water filling channel 111a is disposed on the end surface of one side of the first cover 1111, that is, after the automatic pressurizing machine is connected to the water inlet 111b of the water filling channel 111a, the water loaded by the automatic pressurizing machine flows from the water inlet 111b to the water outlet 111c, and flows into the water filling chamber 200a through the water outlet 111 c. The water inlet 111b of the water filling channel 111a is provided on the side wall of the first cover 1111 to facilitate connection of the water inlet 111b to the automatic pressurizing machine, and in other embodiments, the water inlet 111b of the water filling channel 111a may be provided on the end surface of one side of the first cover 1111 and the water outlet 111c of the water filling channel 111a may be provided on the end surface of the other side of the first cover 1111.

Referring to fig. 4 and 8, in the present embodiment, the water filling channel 111a includes a threaded connection section 111d and an extension section 111e communicated with one end of the threaded connection section 111d, an opening of the threaded connection section 111d away from the extension section 111e is a water inlet 111b, and an opening of the extension section 111e away from the threaded connection section 111d is a water outlet 111 c. The threaded connection section 111d may be used for threaded connection with a water outlet end of the automatic pressurizing machine, or may be used for threaded connection with an adapter, which is then connected with a water outlet end of the automatic pressurizing machine. The threaded connection section 111d is arranged, so that the water injection channel 111a is conveniently communicated with the automatic pressurizing machine, water can be prevented from overflowing from the communication position of the water injection channel 111a and the automatic pressurizing machine in the process that the automatic pressurizing machine loads water to the water injection cavity 200a, and the accuracy of a test result can be further ensured.

Referring to fig. 1 and 2, the guide 123 of the present embodiment is a pull rod, and the first clamping plate 121 and the second clamping plate 122 are disposed on the pull rod in a penetrating manner, wherein the first clamping plate 121 is fixedly connected to the pull rod, and the second clamping plate 122 can slide on the pull rod. The pull rod has simple structure and better guidance, is convenient for production and manufacture, and can save production cost.

In other embodiments, the guide member 123 may be another guiding structure, for example, the guide member 123 may be a guide rail having a guiding surface along which the second clamping plate 122 can slide, or the guide member 123 may be a sliding rail having a sliding slot into which a portion of the second clamping plate 122 extends to enable the second clamping plate 122 to slide along the sliding slot, in short, as long as the second clamping plate 122 can be slidably connected with the guide member 123.

Referring to fig. 1, 5 and 6, in the present embodiment, a portion of the second clamping plate 122 protrudes outward to form an abutment boss 1221. When the concrete sample 200 is clamped between the first clamping plate 121 and the second clamping plate 122, the abutment boss 1221 abuts against the concrete sample 200.

Specifically, since the second clamping plate 122 can slide along the guide 123 under the pushing of the pushing mechanism 124, the abutting boss 1221 is disposed on the second clamping plate 122, so that the displacement of the second clamping plate 122 can be ensured to be in a controllable range, and further the maximum deformation of the concrete sample 200 can be controlled by controlling the maximum displacement of the second clamping plate 122. For example, referring to fig. 6, in the present embodiment, the height H1 of the abutment boss 1221 of the second clamping plate 122 is 10mm, which means that the maximum allowable displacement of the second clamping plate 122 during the process of applying the radial pressure P to the concrete sample 200 by the first clamping plate 121 and the second clamping plate 122 is 10mm, and correspondingly, the maximum allowable deformation of the concrete sample 200 is also 10 mm.

Referring to fig. 1, the number of the pull rods of the present embodiment is two, the two pull rods are arranged in parallel at intervals, and a specimen accommodating space is formed between the two pull rods. In the present embodiment, the two tie rods are spaced in parallel in the vertical direction, that is, when the concrete specimen 200 is clamped between the first clamping plate 121 and the second clamping plate 122, the two tie rods are actually located at two axial ends of the concrete specimen 200, respectively, so that the distance between the two tie rods of the present embodiment needs to be ensured to at least accommodate the concrete specimen 200 after being hermetically connected with the first cover plate assembly 111 and the second cover plate assembly 112, in other embodiments, when the concrete specimen 200 is clamped between the first clamping plate 121 and the second clamping plate 122, the two tie rods can also be located at two radial sides of the concrete specimen 200, in which case, the distance between the two tie rods only needs to be greater than the outer diameter of the concrete specimen 200. One of the two pull rods is arranged at one end of the first clamping plate 121 and the second clamping plate 122 in a penetrating way, and the other of the two pull rods is arranged at the other end of the first clamping plate 121 and the second clamping plate 122 in a penetrating way. The two pull rods are arranged, so that the second clamping plate 122 can be more stable in the sliding process, and the first clamping plate 121 and the second clamping plate 122 can apply radial pressure P to the concrete test piece 200 conveniently.

In other embodiments, the number of tie rods may be adjusted as desired, as long as at least one tie rod is ensured.

Referring to fig. 1, 7 to 10, the first cover 1111 of the present embodiment has a first load avoiding port 1111b and a second load avoiding port 1111c, and the second cover 1121 has a third load avoiding port 1121b and a fourth load avoiding port 1121 c. The concrete test piece 200 is clamped between the first clamping plate 121 and the second clamping plate 122, and when two ends of the water injection cavity 200a are respectively connected with the first cover plate assembly 111 and the second cover plate assembly 112 in a sealing manner, the first loading avoiding port 1111b and the third loading avoiding port 1121b avoid the first clamping plate 121, and the second loading avoiding port 1111c and the fourth loading avoiding port 1121c avoid the second clamping plate 122.

Since the two tie rods of the present embodiment are arranged in parallel at intervals in the vertical direction, by providing the first load avoiding port 1111b and the second load avoiding port 1111c on the first cover plate 1111 and providing the third load avoiding port 1121b and the fourth load avoiding port 1121c on the second cover plate 1121, it is possible to prevent the first clamping plate 121 and the second clamping plate 122 from contacting the first cover plate 1111 and the second cover plate 1121 to affect the test result in the process of applying the radial pressure P to the concrete specimen 200 by the first clamping plate 121 and the second clamping plate 122.

Another embodiment of the present application further provides a method for testing water permeability resistance of concrete, which is implemented by using the apparatus 100 for testing water permeability resistance of concrete provided in the foregoing embodiment. Referring to fig. 11, the method mainly includes the following steps:

s301: dividing a plurality of cylindrical concrete test pieces with water injection cavities into three groups, wherein the three groups of concrete test pieces are respectively a first group of test pieces, a second group of test pieces and a third group of test pieces, the concrete test piece in the first group of test pieces is a concrete test piece I, the concrete test piece in the second group of test pieces is a concrete test piece II, and the concrete test piece in the third group of test pieces is a concrete test piece III;

specifically, the concrete sample 200 of the present embodiment has a geometric dimension of 75mm in inner diameter, 150mm in outer diameter, and 150mm in height. Before the test, the concrete test pieces 200 can be manufactured and maintained according to the mixing proportion of the researched tunnel concrete materials and the regulation of chapter three of test standard of ordinary concrete long-term performance and durability (GB/T50082-2009) according to the mixing proportion of the tunnel concrete materials, six concrete test pieces 200 are prepared in the test method of the embodiment, each group of two concrete test pieces 200 are provided, and the test methods adopted by the concrete test pieces 200 in the same group of test pieces are completely the same. For convenience of description, in the present embodiment, the concrete samples 200 in the first group of samples are collectively referred to as a first concrete sample, but for convenience of distinguishing two first concrete samples in the first group of samples, one of the first concrete samples may be denoted by 1, the other one may be denoted by 2, and similarly, the concrete samples 200 in the second group of samples may be collectively referred to as a second concrete sample, one of the two second concrete samples may be denoted by 3, the other may be denoted by 3, the concrete samples 200 in the third group of samples may be collectively referred to as a third concrete sample, one of the two third concrete samples may be denoted by 5, and the other may be denoted by 6.

It is understood that the number of the concrete samples 200 is not limited to six, and in other embodiments, the number of the concrete samples 200 may be adjusted as needed, but at least one concrete sample 200 in each of the first set of samples, the second set of samples, and the third set of samples is required to be ensured.

S302: the first cover plate assembly and the second cover plate assembly are respectively connected with two ends of a water injection cavity of the concrete test piece I in a sealing mode; loading water reaching a preset water pressure into a water injection cavity of the first concrete sample by using an automatic pressurizing machine until the water seeps out of the outer side wall of the first concrete sample; obtaining the change rule of the concrete permeability coefficient under the stress-free action according to the loading data recorded in the water pressure loading process of the automatic pressurizing machine; the loading data comprises loading water quantities corresponding to different time points of the automatic pressurizing machine in the hydraulic loading process;

specifically, in this embodiment, the hydraulic loading is performed on the first concrete sample, and the external load loading is not performed, so that the change rule of the concrete permeability coefficient obtained by using the first concrete sample is the change rule of the concrete permeability coefficient under the stress-free effect.

Referring to fig. 4, in the embodiment, when the concrete sample is installed, one end of the concrete sample is first placed into the second positioning groove 1121a of the second cover plate 1121, and the second sealing ring 1122 is ensured to extend into the water injection cavity 200a and to be in sealing contact with the sidewall of the water injection cavity 200 a. And then adding water into the water injection cavity 200a of the first concrete sample to remove air, covering the end face of the other end of the first concrete sample with a first cover plate when the water surface is flush with the end face of the other end of the first concrete sample, ensuring that the first sealing ring 1112 extends into the water injection cavity 200a to be in sealing contact with the side wall of the water injection cavity 200a, and then fastening and connecting the first cover plate 1111 and the second cover plate 1121 through bolts 113.

It should be noted that, since the concrete sample is only subjected to the hydraulic loading, and is not subjected to the external load loading, the concrete sample may not be required to be clamped between the first clamping plate 121 and the second clamping plate 122.

After the first cover plate assembly 111 and the second cover plate assembly 112 are respectively connected with two ends of the water injection cavity 200a of the first concrete sample in a sealing manner, the automatic pressurizing machine is communicated with the water injection channel 111a on the first cover plate 1111, the automatic pressurizing machine is opened to enable the water pressure to gradually rise to a preset water pressure, the automatic pressurizing machine of the embodiment can load and stabilize the water pressure within the range of 0-15MPa, the specific required preset water pressure corresponds to the water pressure in the water environment where the concrete lining of the tunnel to be studied is located, optionally, the preset water pressure can be set to be 0.4MPa, 0.8MPa and 1.2MPa, and then the first concrete sample is subjected to water pressure loading until the outer side wall of the first concrete sample seeps out. In the whole hydraulic loading process, the automatic pressurizing machine can automatically record the loading water quantity at intervals of time, for example, at intervals of 30 minutes, so that the loading water quantities corresponding to different time points can be obtained, and the loading water quantities are equivalent to the water seepage quantity of a concrete test piece I, so that the change rule of the concrete permeability coefficient under the stress-free action can be obtained according to the loading water quantities corresponding to different time points. It should be noted that the concrete permeability coefficient is calculated in a specific manner, which belongs to the common general knowledge in the art and is not described herein again.

In addition, the total hydraulic loading time of the automatic pressurizing machine can be determined according to the requirement.

S303: clamping a second concrete sample between the first clamping plate and the second clamping plate, and pushing the second clamping plate by using a pushing mechanism until the second concrete sample is subjected to buckling damage; in the process that the pushing mechanism pushes the second clamping plate, recording the magnitude of the pushing force loaded by the pushing mechanism, and the displacement of the second clamping plate under the action of the pushing forces with different magnitudes, obtaining the change rule of the elastic modulus under the action of no water pressure according to the obtained pushing force loaded by the pushing mechanism and the corresponding displacement of the second clamping plate, and determining the peak value of the pushing force loaded by the pushing mechanism;

specifically, in the present embodiment, the bending moment and the axial force of the concrete-lined vault of the tunnel under study are calculated mainly based on a finite element method using a beam-spring model or a shell-spring model, and the compressive stress of the vault is calculated according to the concrete eccentric compression theory. Subsequently, a finite element model or an elastic mechanical model of the concrete test piece 200 is established, and the change rule of the vault compressive stress under the action of different radial pressures P is calculated. Finally, by means of pressure stress equivalence, the radial pressure P to be applied in the test, that is, the pushing force loaded by the pushing mechanism 124, is obtained.

In this embodiment, the external load is applied to the second concrete sample, and the hydraulic load is not applied, so that the change rule of the elastic modulus of the second concrete sample under the action of no hydraulic pressure is obtained by using the second concrete sample.

It should be noted that, since the second concrete sample is only loaded by an external load, and is not loaded by a hydraulic pressure, the second concrete sample does not need to be hermetically connected with the first cover plate assembly 111 and the second cover plate assembly 112.

In this embodiment, the pushing force applied by the pushing mechanism 124 to the second clamping plate 122 is gradually increased, and the pushing mechanism 124 can set the pushing force at a magnitude required by the test, and each time the pushing mechanism 124 performs loading of the pushing force, the magnitude of the loaded pushing force and the corresponding displacement of the second clamping plate 122 are recorded, and the displacement is measured by a displacement sensor. According to the obtained top thrust loaded by the pushing mechanism 124 and the displacement of the corresponding second clamping plate 122, a pressure-displacement curve can be drawn, and further, the change rule of the elastic modulus under the action of no water pressure and the peak value of the top thrust loaded by the pushing mechanism 124 can be obtained.

In addition, according to needs, the length and the width of the crack generated by the second concrete sample under the action of the pushing forces with different sizes can be recorded, so that the crack change rule of the second concrete sample is obtained.

It should be noted that step S302 and step S303 have no sequence, and the two steps may be interchanged.

S304: the two ends of a water injection cavity of the concrete sample III are respectively in sealing connection with the first cover plate assembly and the second cover plate assembly, and the sealed concrete sample III is clamped between the first clamping plate and the second clamping plate; within a preset time, loading water reaching a preset water pressure into a water injection cavity of a concrete sample III by using an automatic pressurizing machine, and pushing a second clamping plate by using a pushing mechanism, wherein the maximum value of the top thrust loaded by the pushing mechanism is smaller than the peak value of the top thrust loaded by the pushing mechanism obtained in a test on the concrete sample II; obtaining the change rule of the concrete permeability coefficient under the action of an external load according to the loading data recorded in the water pressure loading process of the automatic pressurizing machine; the loading data comprises loading water quantities corresponding to different time points of the automatic pressurizing machine in the hydraulic loading process;

specifically, because the third concrete sample is subjected to water pressure loading and external load loading simultaneously, the change rule of the concrete permeability coefficient obtained by the third concrete sample is used as the change rule of the concrete permeability coefficient under the action of the external load.

For the concrete sample three, the whole test time is determined as required, for example, the preset time may be 12 hours, and in the test process of the concrete sample three, the top thrust applied by the pushing mechanism 124 to the second clamping plate 122 is also gradually increased, but the maximum value of the top thrust loaded by the pushing mechanism 124 is smaller than the peak value of the top thrust loaded by the pushing mechanism 124 obtained in the test of the concrete sample two, that is, the concrete sample three does not need to be damaged under the action of an external load.

In this step, the same manner as that in step S302 is adopted to obtain the loading data recorded by the automatic pressurizing machine in the hydraulic loading process, and the change rule of the concrete permeability coefficient under the action of the external load is obtained according to the obtained loading data.

In addition, if necessary, the change law of the elastic modulus under the action of the water pressure can also be obtained in the same manner as in step S303.

S305: and comparing the change rule of the concrete permeability coefficient under the action of the external load with the change rule of the concrete permeability coefficient under the action of no stress to determine the influence of the mechanical damage of the concrete on the concrete permeability under the action of the external load.

Further, after the above test is completed, the concrete sample three may be split in the radial direction to observe the difference in permeability at different positions in the concrete sample three, if necessary.

Since the concrete sample 200 of the present embodiment has a structure and a load pattern close to those of the concrete lining of the tunnel, the test results can evaluate the permeability of the concrete lining of the tunnel in a high water pressure environment.

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

Claims (11)

1. The utility model provides a concrete water permeability resistance test device for carry out water permeability resistance test to columniform concrete sample, the concrete sample has along the axial runs through the water injection chamber of concrete sample, its characterized in that includes:

the hydraulic loading device comprises an automatic pressurizing machine, a first cover plate assembly and a second cover plate assembly, wherein the first cover plate assembly and the second cover plate assembly are respectively connected with two ends of the concrete test piece in a sealing mode, and the first cover plate assembly is provided with a water injection channel used for communicating the automatic pressurizing machine with the water injection cavity;

the external load loading device comprises a first clamping plate, a second clamping plate, a guide piece, a pushing mechanism, a mounting plate and a displacement sensor; the first clamping plate is fixedly connected with the guide piece, the second clamping plate is connected with the guide piece in a sliding mode, and the first clamping plate and the second clamping plate are used for clamping the concrete specimen from two radial sides of the concrete specimen; the mounting plate is fixedly connected with the guide piece and is positioned on one side, far away from the first clamping plate, of the second clamping plate, the pushing mechanism is mounted on the mounting plate, and the telescopic pushing part of the pushing mechanism faces towards the second clamping plate; the displacement sensor is connected with the first clamping plate and the second clamping plate and used for detecting the displacement of the second clamping plate in the process that the pushing mechanism pushes the second clamping plate.

2. The concrete water permeability resistance test device according to claim 1, wherein the first cover plate assembly comprises a first cover plate having the water filling channel, and a first sealing ring disposed at one side of the first cover plate, the first sealing ring being located at a peripheral side of a water outlet of the water filling channel; the first sealing ring is used for being in sealing contact with the end face of one end of the concrete test piece;

the second cover plate assembly comprises a second cover plate and a second sealing ring arranged on one side of the second cover plate; and the second sealing ring is used for being in sealing contact with the end face of the other end of the concrete test piece.

3. The concrete water permeability resistance test device according to claim 2, wherein one side of the first cover plate is provided with a first positioning groove for matching with one end of the concrete test piece, the water injection channel is communicated with the first positioning groove, and the first sealing ring is arranged in the first positioning groove;

one side of the second cover plate is provided with a second positioning groove used for being matched with the other end of the concrete test piece, and the second sealing ring is arranged in the second positioning groove.

4. The concrete water permeability resistance test device according to claim 1, wherein the first cover plate assembly comprises a first cover plate, the water inlet of the water injection channel is arranged on the side wall of the first cover plate, and the water outlet of the water injection channel is arranged on the end face of one side of the first cover plate.

5. The concrete water permeability test device according to claim 4, wherein the water injection channel comprises a threaded connection section and an extension section communicated with one end of the threaded connection section, the opening of the threaded connection section far away from one end of the extension section is the water inlet, and the opening of the extension section far away from one end of the threaded connection section is the water outlet.

6. The concrete water permeability resistance test device of claim 1, wherein the first cover plate assembly is fastened to the second cover plate assembly.

7. The concrete water permeability resistance test device according to claim 1, wherein a part of the structure of the second clamping plate protrudes outwards to form an abutting boss;

when the concrete test piece is clamped between the first clamping plate and the second clamping plate, the abutting lug boss abuts against the concrete test piece.

8. The apparatus according to claim 7, wherein the guide member is a pull rod, and the first clamping plate and the second clamping plate are both disposed on the pull rod.

9. The concrete water permeability resistance test device according to claim 8, wherein the number of the pull rods is two, the two pull rods are arranged in parallel at intervals, and a test piece accommodating space is formed between the two pull rods;

one of the two pull rods penetrates through one end of the first clamping plate and one end of the second clamping plate, and the other of the two pull rods penetrates through the other end of the first clamping plate and the other end of the second clamping plate.

10. The concrete water permeability resistance test device according to claim 9, wherein two of the tie rods are spaced apart in parallel in the vertical direction, the first cover plate assembly comprises a first cover plate having a first loading escape opening and a second loading escape opening, the second cover plate having a third loading escape opening and a fourth loading escape opening;

the concrete sample is held between the first clamping plate and the second clamping plate, the two ends of the water injection cavity are respectively connected with the first cover plate assembly and the second cover plate assembly in a sealing mode, the first loading is used for avoiding the port and the third loading is used for avoiding the port and the first clamping plate, the second loading is used for avoiding the port and the fourth loading is used for avoiding the port and the second clamping plate.

11. A method for testing the water permeability resistance of concrete, which is implemented by using the apparatus for testing the water permeability resistance of concrete according to any one of claims 1 to 10, and which comprises the following steps:

dividing a plurality of cylindrical concrete test pieces with water injection cavities into three groups, wherein the three groups of concrete test pieces are respectively a first group of test pieces, a second group of test pieces and a third group of test pieces, the concrete test piece in the first group of test pieces is a concrete test piece I, the concrete test piece in the second group of test pieces is a concrete test piece II, and the concrete test piece in the third group of test pieces is a concrete test piece III;

the first cover plate assembly and the second cover plate assembly are respectively connected with two ends of the water injection cavity of the concrete test piece I in a sealing mode; loading water reaching a preset water pressure into the water injection cavity of the first concrete test piece by using the automatic pressurizing machine until the water seeps out of the outer side wall of the first concrete test piece; obtaining the change rule of the concrete permeability coefficient under the stress-free action according to the loading data recorded by the automatic pressurizing machine in the water pressure loading process; the loading data comprises loading water quantities corresponding to different time points of the automatic pressurizing machine in a hydraulic loading process;

clamping the second concrete sample between the first clamping plate and the second clamping plate, and pushing the second clamping plate by using the pushing mechanism until the second concrete sample is subjected to bending damage; recording the magnitude of the top thrust loaded by the pushing mechanism in the process of pushing the second splint by the pushing mechanism, and recording the displacement of the second splint under the action of the top thrusts with different magnitudes, obtaining the change rule of the elastic modulus under the action of no water pressure according to the obtained top thrust loaded by the pushing mechanism and the corresponding displacement of the second splint, and determining the peak value of the top thrust loaded by the pushing mechanism;

the two ends of the water injection cavity of the concrete sample III are respectively in sealing connection with the first cover plate assembly and the second cover plate assembly, and the sealed concrete sample III is clamped between the first clamping plate and the second clamping plate; within a preset time, loading water reaching a preset water pressure into the water injection cavity of the concrete sample III by using the automatic pressurizing machine, and pushing the second clamping plate by using the pushing mechanism, wherein the maximum value of the top thrust loaded by the pushing mechanism is smaller than the peak value of the top thrust loaded by the pushing mechanism obtained in the test of the concrete sample II; obtaining the change rule of the concrete permeability coefficient under the action of an external load according to the loading data recorded in the water pressure loading process of the automatic pressurizing machine; the loading data comprises loading water quantities corresponding to different time points of the automatic pressurizing machine in a hydraulic loading process;

and comparing the obtained change rule of the concrete permeability coefficient under the action of the external load with the change rule of the concrete permeability coefficient under the action of the unstressed load to determine the influence of the mechanical damage of the concrete on the concrete permeability under the action of the external load.

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