Grouting test device and method for simulating secondary lining concrete defects

Abstract

The invention discloses a grouting test device and method for simulating secondary lining concrete defects, the test device comprises a test platform and a small grouting machine capable of adjusting grouting pressure, the small grouting machine is connected with a defective concrete test piece test mold through a grouting pipe, the grouting pipe is provided with a pressure gauge, the pressure gauge is connected with data collection equipment, and the data collection equipment is connected with the test platform. All parts of the defective concrete test piece test mold are detachably connected, so that grouting can be completed in different grouting modes and different grouting pressures; the test method comprises the following steps: designing and manufacturing concrete test pieces with different defects, simulating secondary lining in-mold grouting, completing grouting of the test pieces in different solidification stages by adopting different grouting pressures and different grouting modes, detecting the obtained test pieces, researching and analyzing the influence of the grouting pressures, the grouting opportunity and the grouting modes on secondary lining grouting, and obtaining optimal grouting parameters. According to the device and the method, tunnel concrete secondary lining in-mold grouting and defect repair are truly simulated, so that test samples and test data are provided for research of tunnel grout and defect repair engineering.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel secondary lining strip mold grouting and simulation test technology, and in particular to a grouting test device and method for simulating secondary lining concrete defects. Technical Background

[0002] The secondary lining grouting technology with formwork has been widely used in the construction of railway tunnels, and has a good effect on preventing the secondary lining vault of railway tunnels from degassing. The secondary lining vault grouting technology first designs and transforms the secondary lining trolley, sets grouting holes on the vault of the lining trolley template, and installs auxiliary facilities for grouting. The grouting pipe is pre-buried before pouring concrete. After the secondary lining concrete is poured, the formwork is not removed to prevent the degassing of the secondary lining vault.

[0003] The voids or loose defects in the secondary lining concrete structure reduce the bearing capacity and durability of the tunnel, posing a threat to the safety performance of the tunnel. Simulation test is a key means to study the defect molding method, the optimal grouting pressure, the grouting process detection and the grouting effect detection. To achieve accurate and visual secondary lining defect grouting simulation test, the key lies in the precise design of defect specimen molding and grouting system and the scientific control of its parameters.

[0004] Grouting pressure is a key parameter in the construction of grouting with formwork, which directly affects the grouting effect and the mechanical properties of concrete. At present, a lot of research and improvement have been done in the research of construction methods and detection technology, but the influence of different grouting pressures on the strength of concrete has been less studied. Therefore, it is of great practical significance to study the influence of grouting pressure with formwork on the mechanical properties of concrete in the tunnel secondary lining defect repair project. Summary of the invention

[0005] The purpose of the present invention is to provide a grouting test device and method for simulating defects in secondary lining concrete, which can be used to make concrete specimens with different defects, and utilize different grouting pressures to simulate the secondary lining strip mold grouting of concrete specimens with different defects at different solidification stages, thereby providing test samples and test data for experimental research on tunnel secondary lining strip mold grouting and defect repair engineering.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A grouting test device for simulating secondary lining concrete defects comprises a test platform, a small grouting machine is fixed on the test platform, the grouting pressure of the small grouting machine is adjustable, and a defective concrete specimen mold is also included. The defective concrete specimen mold is modularly detachably connected. The small grouting machine is connected to the defective concrete specimen mold through a grouting pipe. The grouting pipe is provided with a pressure gauge, and the pressure gauge is connected to a data collection device.

[0008] Furthermore, the defective concrete specimen mold has an overall cubic structure, including a bottom plate, a type I side plate, a type II side plate, a top plate, a grouting hole and an exhaust hole bracket, two type I side plates and two type II side plates are provided respectively, and the bottom plate, the type I side plate, the type II side plate, the top plate, the grouting hole and the exhaust hole bracket are detachably connected; the type I side plate is a flat plate without a groove, and two vertical grooves are symmetrically provided on the inner side of the type II side plate, and the groove width is greater than the thickness of the type I side plate, the type I side plate and the type II side plate are vertically connected to form a rectangular internal space, the type I side plate is stuck between the grooves of the two type II side plates, and the bottom plate is provided with four grooves that can accommodate the type I side plate and the type II side plate The side panels are vertically inserted into the grooves, and the Type I side panels and the Type II side panels are vertically stuck in the grooves of the bottom panel. The bottom of the grooves on the Type II side panels and the bottom panel are provided with sealing strips; the top panel is vertically arranged on the top of the Type I side panels and the Type II side panels, and a groove is also arranged at the bottom of the top panel. The grooves of the top panel and the bottom panel have the same size, and a first grouting port and a first exhaust port are arranged on the top panel; a connecting joint is arranged on the grouting hole and the exhaust hole bracket, and a second grouting port and a second exhaust port are arranged inside the connecting joint, the second grouting port is connected with the first grouting port, and the second exhaust port is connected with the first exhaust port. The grouting hole and the exhaust hole bracket are arranged on the upper part of the top panel, and the connecting joint is connected with the grouting pipe.

[0009] The test mold for defective concrete specimens adopts a modular design. By setting grooves on the modular bottom plate, type I side plate, type II side plate, top plate, grouting hole and exhaust hole bracket, the various parts are cleverly connected and fixed. In order to ensure that the groove joints are dense and leak-proof during grouting, a sealing strip is set at the bottom of each groove.

[0010] Furthermore, the edges of the Type II side panels, top panel, bottom panel, grouting hole and vent hole brackets are all provided with tie rod holes, and the two Type II side panels are connected by a double-threaded tie rod, which passes through the tie rod holes on the Type II side panels, and ring nuts are provided at both ends of the double-threaded tie rod; the top panel, bottom panel, grouting hole and vent hole brackets are connected by a single-threaded tie rod, which passes through the tie rod holes on the top panel, bottom panel and grouting hole and vent hole brackets, a ring nut is provided on the threaded end, and the threaded end is provided on one side of the top panel and the grouting hole and vent hole bracket.

[0011] Threaded tie rods are used between the two II-type side plates, between the bottom plate and the top plate, and between the grouting hole and the exhaust hole bracket to strengthen the connection of the defective concrete specimen mold, so that the defective concrete specimen mold is not prone to leakage when pouring concrete or simulating grouting with the second lining mold, providing a closed space. At the same time, the design of the ring nut is more convenient for adjustment.

[0012] Furthermore, the grouting hole and exhaust hole bracket includes a square connecting bottom plate, a cylindrical protrusion is provided on the square connecting bottom plate, and a second grouting port and a second exhaust port are provided inside the cylindrical protrusion and penetrate the cylindrical protrusion and the square connecting bottom plate.

[0013] The grouting hole and vent hole brackets have two functions. The first function is to locate the grouting holes and vent holes. When casting defective concrete specimens, steel bars or round tubes are inserted into the concrete defects. When the concrete is initially set, the steel bars or round tubes are pulled out to form grouting holes and vent holes. The second function is to connect the grouting pipe, which can be connected to the grouting pipe through the connecting joint for grouting.

[0014] Furthermore, the test mould of the defective concrete specimen is made of steel plate.

[0015] The defective concrete specimen test mold is designed with steel plates so that it is not easily damaged during the disassembly process and can be recycled many times, which is more resource-saving and environmentally friendly.

[0016] Furthermore, a support leg is provided at the bottom of the test platform, and a universal wheel is provided at the end of the support leg.

[0017] The test platform is designed to be movable, making it easy to move. It can be pushed to the designated position during the test and pushed back after the test is completed.

[0018] A grouting test method for simulating secondary lining concrete defects comprises the following steps:

[0019] S1. Test preparation: according to the required concrete specimen size, a defective concrete specimen mold is made, including a bottom plate, a type I side plate, a type II side plate, a top plate, a grouting hole and a vent hole bracket, and the bottom plate, the type I side plate, and the type II side plate are fixedly connected. The number of defective concrete specimen molds to be made is determined according to the test design, and then each defective concrete specimen mold is numbered;

[0020] S2 makes defective concrete specimens: stir concrete, and manually cast each defective concrete specimen mold to respectively make top hollow specimens, top loose specimens, internal hollow specimens, internal loose specimens, and control specimens without defects; after casting, install and fix the grouting hole and vent bracket, and insert steel bars or water pipes into the defects of the defective concrete specimens to make reserved grouting holes and vents, wherein half of the top hollow specimens and the top loose specimens do not have reserved grouting holes and vents; when the concrete is initially set, pull out the steel bars or water pipes to form grouting holes and vents, then remove the grouting hole and vent bracket, install the top, and reinstall the grouting hole and vent bracket on the top of the top plate, and fix them with single-head threaded tie rods and ring nuts, and finally use sealant to seal the entire defective concrete specimen mold for grouting;

[0021] S3. Grouting: Grouting is performed on the prepared top hollow specimens, top loose specimens, internal hollow specimens, and internal loose specimens at different grouting pressures and different grouting methods at the time of initial setting, initial setting-final setting, and final setting of the concrete. The grouting pressure is adjusted by a small grouting machine, and a pressure gauge is used to record the grouting pressure. There are two grouting methods. For specimens with reserved grouting holes, grouting is performed through the grouting holes. For some top hollow specimens and top loose specimens without reserved grouting holes and exhaust holes, grouting is performed directly from top to bottom.

[0022] S4. Specimen curing: After the grouting is completed, the defective concrete specimen mold is removed after the specimen has initially set, and the specimen is professionally cured;

[0023] S5. Compression test: After the concrete age of the specimen reaches 28 days, non-destructive testing is carried out using geological radar;

[0024] S6. Data collation and analysis: Compare the geological radar nondestructive testing images of defective concrete specimens with those of non-defective concrete specimens to study the effects of grouting pressure, grouting time and grouting method on the density of defective concrete after grouting in formwork.

[0025] Furthermore, the method for making concrete specimens with different defects is as follows: when making specimens with top voids, some space is left at the top when concrete is filled to form a top void; when making specimens with loose tops, when concrete is added to 20 mm from the top of the test mold, crushed stone is used to fill 20 mm to be flush with the top of the test mold; when making specimens with internal voids, a balloon is used to fill the middle of the concrete, and the grouting hole and the vent hole bracket are fixed to the balloon position. When the specimen reaches initial setting, the grouting hole and the vent hole bracket are removed, and the balloon debris is taken out using the grouting hole and the vent hole to form an internal void; when making specimens with loose interiors, the specimens are loaded in three layers. After the first layer of concrete is filled, 20 mm of crushed stone is filled in the middle part and then the second layer of concrete is filled. After the specimen is initially set, a loose phenomenon is formed in the middle.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention utilizes a small grouting machine with adjustable pressure and the detection and recording functions of a pressure gauge to accurately control the grouting pressure, and simulates the completion of the second lining strip mold grouting under different grouting pressures, different grouting methods, and different concrete solidification stages, thereby providing reliable test samples and test data for the experimental research of tunnel second lining strip mold grouting and defect repair engineering.

[0028] 2. The defective concrete specimen mold in the present invention is made of steel plates and adopts a modular design, wherein the bottom plate, I-type side plates, II-type side plates, top plate, grouting holes and exhaust hole brackets are all detachably connected by grooves and threaded pull rods, which is convenient for disassembly and adjustment. After the defective concrete specimen is solidified, the various parts can be disassembled to easily take out the specimen. The steel plate design makes it difficult to be damaged during the disassembly process and can be recycled for multiple times.

[0029] 3. The reasonable and ingenious design of the defective concrete specimen mold of the present invention can complete the production of different types of defective concrete specimens. The grouting hole and the exhaust hole bracket can provide accurate positioning for the setting of the grouting hole and the exhaust hole, and is convenient for connection with the grouting pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the overall structure of the test device according to an embodiment of the present invention;

[0031] Figure 2 It is a front view of a test mold of a defective concrete specimen according to an embodiment of the present invention;

[0032] Figure 3 A top view of a test mold of a defective concrete specimen according to an embodiment of the present invention;

[0033] Figure 4 for Figure 3 An enlarged schematic diagram of part I;

[0034] Figure 5 This is a schematic diagram of the structure of the bottom plate of the test mold for a defective concrete specimen according to an embodiment of the present invention;

[0035] Figure 6 Schematic diagram of the top plate structure of the test mold for defective concrete specimens according to an embodiment of the present invention;

[0036] Figure 7 Schematic diagram of the side plate structure of type II of the defective concrete specimen test mold according to an embodiment of the present invention;

[0037] Figure 8 It is a schematic diagram of the support structure of the grouting holes and the exhaust holes of the test mold of the defective concrete specimen according to an embodiment of the present invention;

[0038] Fig. 9 Schematic diagram of the casting structure corresponding to two grouting methods of the top cavity specimen of the embodiment of the present invention;

[0039] Fig.10 It is a schematic diagram of the casting structure corresponding to two grouting methods of the top non-dense test piece of an embodiment of the present invention;

[0040] Fig.11 This is a schematic diagram of the casting structure of the internal cavity test piece according to an embodiment of the present invention;

[0041] Fig.12This is a schematic diagram of the casting structure of the internal non-dense test piece of an embodiment of the present invention;

[0042] Fig.13 This is a schematic diagram of the casting structure of the control specimen of the embodiment of the present invention;

[0043] Fig.14 It is the technical roadmap of the present invention;

[0044] Figure numerals: 1, test platform; 2, small grouting machine; 3, defective concrete specimen test mold; 3-1, bottom plate; 3-2, type I side; 3-3, plate type II side plate; 3-4, top plate; 3-4-1, first grouting port; 3-4-2, first exhaust port; 3-5; grouting hole and exhaust hole bracket; 3-5-1, square connecting bottom plate; 3-5-2, connecting joint; 3-5-3, second grouting port; 3-5-4, second exhaust port; 3-6, groove; 3-7, sealing strip ;3-8, tie rod hole;3-9, double-threaded tie rod;3-10, ring nut;3-11, single-threaded tie rod;4, pressure gauge;5, data cable;6, data collection equipment;7, outrigger;8, universal wheel;9, steel bar;10, top hollow specimen;11, top loose specimen;12, internal hollow specimen;13, internal loose specimen;14, control specimen;15, concrete layer;16 gravel;17, balloon;18, top hollow;19, internal hollow. DETAILED DESCRIPTION

[0045] The technical solution of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] 1. Test equipment

[0047] like Figure 1 As shown, a grouting test device for simulating secondary lining concrete defects includes a test platform 1, on which a small grouting machine 2 is fixed, the grouting pressure of the small grouting machine 2 is adjustable, and a detachable defective concrete specimen mold 3 is included. The small grouting machine 2 is connected to the defective concrete specimen mold 3 through a grouting pipe 4, and a pressure gauge 5 is provided on the grouting pipe 4, and the pressure gauge 5 is connected to a data collection device 7 through a data line 6.

[0048] like Figures 2 to 8As shown, the defective concrete specimen mold 3 is a cubic structure as a whole, including a bottom plate 3-1, a type I side plate 3-2, a type II side plate 3-3, a top plate 3-4, and a grouting hole and exhaust hole bracket 3-5, and all of them are made of steel plates. Two I-type side panels 3-2 and two II-type side panels 3-3 are provided, the I-type side panel 3-2 is a flat plate without grooves, two vertical grooves 3-6 are symmetrically provided on the inner side of the II-type side panel 3-3, the width of the grooves 3-6 is greater than the thickness of the I-type side panel 3-2, the I-type side panel 3-2 and the II-type side panel 3-3 are vertically connected and enclose a square internal space, the I-type side panel 3-2 is stuck between the grooves 3-6 of the two II-type side panels, the bottom plate 3-1 is provided with four grooves 3-6 for accommodating the I-type side panel 3-2 and the II-type side panel 3-3 to be vertically inserted, the I-type side panel 3-2 and the II-type side panel 3-3 are vertically stuck in the grooves 3-6 of the bottom plate 3-1; the top plate 3-4 is vertically arranged on the top of the I-type side panel 3-2 and the II-type side panel 3-3 A groove 3-6 is also provided at the bottom of the top plate 3-4. The outer dimensions of the top plate 3-4 and the bottom plate 3-1 and the size of the groove 3-6 are the same, and a first grouting port 3-4-1 and a first exhaust port 3-4-2 are provided on the top plate 3-4; a sealing strip 3-7 is provided at the bottom of the groove 3-6 on the II-type side plate 3-3, the bottom plate 3-1 and the top plate 3-4; a connecting joint 3-5-2 is provided on the grouting hole and exhaust hole bracket 3-5, and a second grouting port 3-5-3 and a second exhaust port 3-5-4 which are connected with the first grouting port 3-4-1 and the first exhaust port 3-4-2 are provided. During grouting, the grouting hole and exhaust hole bracket 3-5 are arranged on the upper part of the top plate 3-4, and the connecting joint 3-5-1 is connected to the grouting pipe 4.

[0049] The connection method between the bottom plate 3-1, the I-type side plate 3-2, the II-type side plate 3-3, the top plate 3-4, the grouting hole and the exhaust hole bracket 3-5 is:

[0050] The edges of the II-type side panels 3-3, the top panel 3-4, the bottom panel 3-1, and the grouting hole and exhaust hole bracket 3-5 are all provided with tie rod holes 3-8. The two II-type side panels 3-3 are connected by a double-threaded tie rod 3-9, which passes through the tie rod holes 3-8 on the II-type side panels 3-3, and ring nuts 3-10 are provided at both ends of the double-threaded tie rod 3-9; the top panel 3-4, the bottom panel 3-1, and the grouting hole and exhaust hole bracket 3-5 are connected by a single-threaded tie rod 3-11, which passes through the tie rod holes 3-8 on the top panel 3-4, the bottom panel 3-1, and the grouting hole and exhaust hole bracket 3-5, and a ring nut 3-10 is provided on the threaded end, and the threaded end is provided on one side of the top panel 3-4 and the grouting hole and exhaust hole bracket 3-5.

[0051] In this embodiment, the grouting hole and exhaust hole bracket 3-5 includes a square connecting base plate 3-5-1, a cylindrical protrusion is provided on the square connecting base plate 3-5-1, the square connecting base plate 3-5-1 and the cylindrical protrusion are fixed by welding, and the outer side of the cylindrical protrusion is threaded with a pipe as a connecting joint 3-5-2, and a second grouting port 3-5-3 and a second exhaust port 3-5-4 are opened in the center of the connecting joint 3-5-2, and the second grouting port 3-5-3 and the second exhaust port 3-5-4 pass through the square connecting base plate 3-5-1, the second grouting port 3-5-3 corresponds to the first grouting port 3-4-1 on the top plate 3-4, and the second exhaust port 3-5-4 corresponds to the first exhaust port 3-4-2 on the top plate 3-4.

[0052] In this embodiment, a support leg 8 is further provided at the bottom of the test platform 1, and a universal wheel 9 is provided at the end of the support leg 8 for easy movement.

[0053] 2. Test methods and test process

[0054] S1. Experimental preparation

[0055] like Fig.14 As shown in the technical roadmap of the present invention, first, the bottom plate 3-1, type I side plate 3-2, type II side plate 3-3, top plate 3-4, grouting hole and exhaust hole bracket 3-5 of the defective concrete specimen test mold 3 are cut according to the specimen size required for the test, and then the type I side plate 3-2, type II side plate 3-3 and top plate 3-4 are connected, wherein the type I side plate 3-2 and the type II side plate 3-3 are vertically stuck in the groove 3-6 on the bottom plate 3-1, and then fixed with a double-headed threaded pull rod 3-9 and a ring nut 3-10.

[0056] Among them, the specimen size is selected as 200mm×200mm×200mm, and a total of 92 defective concrete specimen molds 3 are made. It is planned to make 30 top hollow specimens 10, 30 top non-dense specimens 11, 15 internal hollow specimens 12, 15 internal non-dense specimens 13, and 2 control specimens 14 without defects. Then, each defective concrete specimen mold 3 is classified and numbered;

[0057] S2. Making defective concrete specimens

[0058] Mixing concrete, manually filling and pouring concrete into each defective concrete specimen mold 3 according to the number on the defective concrete specimen mold 3 using different methods; Figure 9-13As shown, when the top hollow test piece 10 is made, some space is left at the top when the concrete is filled, forming a top hollow 18; when the top loose test piece 11 is made, when the concrete is added to 20mm from the top of the test mold, crushed stone 16 is used to fill 20mm and flush with the top of the test mold; when the internal hollow test piece 12 is made, a balloon 17 is used to fill the middle of the concrete, and the steel bar 9 or water pipe is fixed to the position of the balloon 17 through the grouting hole and the exhaust hole bracket 3-5. When the test piece reaches the initial setting, the grouting hole and the exhaust hole bracket 3-5 and the steel bar 9 or water pipe are removed, and the slag of the balloon 17 is taken out by the grouting hole and the exhaust hole to form an internal hollow 19; when the internal loose test piece 13 is made, the test piece is loaded in three layers during production. After the first concrete layer 15 is poured, 20mm crushed stone 16 is filled in the middle part and then the second concrete layer 15 is poured. After the test piece is initially set, the middle is loose.

[0059] After the concrete pouring is completed, the grouting holes and vent brackets 3-5 are fixed on the top of the test mold of 15 top hollow test pieces 10, 15 top non-dense test pieces 11, 15 internal hollow test pieces 12, 15 internal non-dense test pieces 13, and 2 control test pieces 14 without defects, and steel bars 9 or water pipes are inserted into the defects of the defective concrete test pieces to make reserved grouting holes and vent holes. When the concrete is initially set, the steel bars 9 or water pipes are pulled out to form grouting holes and vent holes, and then the grouting holes and vent brackets 3-5 are removed, and finally 15 top hollow test pieces 10, 15 reserved grouting holes are obtained. 11 specimens with loose tops of grouting holes, 15 specimens with hollow interiors of reserved grouting holes, 12 specimens with loose interiors of reserved grouting holes, 13 specimens with loose tops of reserved grouting holes, 15 specimens with hollow tops without grouting holes, 10 specimens with loose tops without grouting holes, 11 specimens with loose tops without grouting holes, and 2 control specimens without defects, 14; then, the top plate 3-1 is installed on the 92 specimen molds, and the grouting holes and exhaust hole brackets 3-5 are reinstalled on the top of the top plate 3-1, and fixed by single-head threaded tie rods 3-11 and ring nuts 3-10, and finally, the entire defective concrete specimen mold 3 is sealed with sealant to wait for grouting.

[0060] S3. Grouting

[0061] As shown in the figure, 60 concrete specimens with four different defects and reserved grouting holes were grouted through the reserved grouting holes at grouting pressures of 0.5 MPa, 1.0 MPa, 1.5 MPa, 2.0 MPa, and 2.5 MPa at the time of initial setting, initial setting-final setting, and after final setting; for the other 15 specimens 10 with hollow tops without grouting holes and 15 specimens 11 with loose tops without grouting holes, direct grouting from top to bottom was adopted at grouting pressures of 0.5 MPa, 1.0 MPa, 1.5 MPa, 2.0 MPa, and 2.5 MPa at the time of initial setting, initial setting-final setting, and after final setting.

[0062] S4. Specimen curing

[0063] After the initial setting of 92 specimens, the defective concrete specimen mold 3 was removed and the specimens were professionally maintained.

[0064] S5. Compression test

[0065] After the concrete age of the 92 specimens reached 28 days, non-destructive testing was carried out using geological radar.

[0066] S6. Data Arrangement and Analysis

[0067] The geological radar nondestructive testing images of 90 defective concrete specimens were grouped and compared with those of non-defective concrete specimens, and the effects of grouting pressure, grouting time and grouting method on the density of defective concrete after grouting in formwork were studied respectively.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A grouting test device for simulating secondary lining concrete defects, comprising a test platform, characterized in that: The test platform is fixed with a small grouting machine, the grouting pressure of which is adjustable, and also includes a defective concrete specimen mold, which is modularly detachably connected, and the small grouting machine is connected to the defective concrete specimen mold through a grouting pipe, and the grouting pipe is provided with a pressure gauge, which is connected to a data collection device.

2. The grouting test device for simulating secondary lining concrete defects according to claim 1 is characterized in that: The defective concrete specimen mold includes a bottom plate, a type I side plate, a type II side plate, a top plate, a grouting hole and an exhaust hole bracket, two of the type I side plates and two of the type II side plates are arranged respectively, the type I side plate is a flat plate without a groove, and two vertical grooves are symmetrically arranged on the inner side of the type II side plate, the two sides of the type I side plate are stuck in the grooves of the two type II side plates, and form a rectangular internal space with the type II side plates; the bottom plate and the top plate are also provided with grooves, the type I side plate and the type II side plate are vertically stuck in the grooves of the bottom plate and the top plate, and the top plate is provided with a first grouting port and a first exhaust port, and sealing strips are arranged at the bottom of all the grooves; the grouting hole and the exhaust hole bracket are arranged on the top of the top plate, and a connecting joint for connecting to a grouting pipe is provided on the grouting hole and the exhaust hole bracket, and a second grouting port and a second exhaust port are arranged inside the connecting joint, the second grouting port is connected with the first grouting port, and the second exhaust port is connected with the first exhaust port.

3. The grouting test device for simulating secondary lining concrete defects according to claim 2 is characterized in that: The edges of the Type II side panels, top panel, bottom panel, grouting hole and vent hole brackets are all provided with tie rod holes, and the two Type II side panels are connected by a double-threaded tie rod, which passes through the tie rod holes on the Type II side panels, and ring nuts are provided at both ends of the double-threaded tie rod; the top panel, bottom panel, grouting hole and vent hole brackets are connected by a single-threaded tie rod, which passes through the tie rod holes on the top panel, bottom panel and the grouting hole and vent hole brackets, a ring nut is provided on the threaded end, and the threaded end is provided on one side of the top panel and the grouting hole and vent hole brackets.

4. The grouting test device for simulating secondary lining concrete defects according to claim 2 or 3, characterized in that: The grouting hole and exhaust hole bracket comprises a square connecting bottom plate, a cylindrical protrusion is arranged on the square connecting bottom plate, and a second grouting port and a second exhaust port are arranged inside the cylindrical protrusion and penetrate the cylindrical protrusion and the square connecting bottom plate.

5. The grouting test device for simulating secondary lining concrete defects according to claim 2 is characterized in that: The defective concrete specimen test mold is made of steel plate.

6. The grouting test device for simulating secondary lining concrete defects according to claim 1 is characterized in that: The bottom of the test platform is provided with supporting legs, and the ends of the supporting legs are provided with universal wheels.

7. A grouting test method for simulating secondary lining concrete defects, characterized in that: The following steps are involved: S1. Test preparation: determine the size of the concrete specimen, cut materials to make a defective concrete specimen mold, including a bottom plate, a type I side plate, a type II side plate, a top plate, a grouting hole and a vent hole bracket, and fix the bottom plate, the type I side plate, and the type II side plate together. The number of defective concrete specimen molds to be made is determined according to the test design, and then each defective concrete specimen mold is grouped and numbered; S2 makes defective concrete specimens: stir concrete, and manually pour each defective concrete specimen mold to make top hollow specimens, top loose specimens, internal hollow specimens, internal loose specimens, and control specimens without defects; after pouring, install and fix the grouting hole and vent hole brackets, insert steel bars or water pipes from the grouting hole and vent hole brackets into the defects, and reserve grouting holes and vent holes, wherein half of the top hollow specimens and the top loose specimens do not reserve grouting holes and vent holes; when the concrete is initially set, pull out the steel bars or water pipes to form grouting holes and vent holes, then remove the grouting hole and vent hole brackets, install the top, and reinstall the grouting hole and vent hole brackets on the top of the top plate, and fix them with single-head threaded tie rods and ring nuts, and finally use sealant to seal the entire defective concrete specimen mold for grouting; S3. Grouting: Grouting is performed on the prepared top hollow specimens, top loose specimens, internal hollow specimens, and internal loose specimens at different grouting pressures and different grouting methods at the time of initial setting, initial setting-final setting, and final setting of the concrete. The grouting pressure is adjusted by a small grouting machine, and a pressure gauge is used to record the grouting pressure. There are two grouting methods. For specimens with reserved grouting holes and vents, grouting is performed through the grouting holes. For some top hollow specimens and top loose specimens without reserved grouting holes and vents, grouting is performed directly from top to bottom. S4. Specimen curing: After the grouting is completed, the defective concrete specimen mold is removed after the specimen has initially set, and the specimen is professionally cured; S5. Compression test: After the concrete age of the specimen reaches 28 days, non-destructive testing is carried out using geological radar; S6. Data collation and analysis: Compare the geological radar nondestructive testing images of defective concrete specimens with those of non-defective concrete specimens to study the effects of grouting pressure, grouting time and grouting method on the density of defective concrete after grouting in formwork.

8. The grouting test method for simulating secondary lining concrete defects according to claim 7 is characterized in that: In step S2, the method for preparing concrete specimens with different defects is as follows: Top void specimen: When concrete is filled, some space is left at the top to form a top void; Specimens with loose top: When concrete is added to the 20mm distance from the top of the test mold, use crushed stone to fill 20mm to the same level as the top of the test mold; Internal void specimen: Use balloons to fill the middle of the concrete, fix the grouting holes and venting holes brackets to the balloon position, remove the grouting holes and venting holes brackets when the specimen reaches initial setting, and use the grouting holes and venting holes to take out the balloon debris to form an internal void; Internally non-compacted specimens: The specimens are made into three layers. After the first layer of concrete is filled, 20mm crushed stone is filled in the middle part and then the second layer of concrete is filled. After the specimen is initially set, the middle part becomes non-compact.

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