A frost heave strain experimental device for concrete lined channels

Abstract

The present invention provides a frost heave strain test device for a concrete lined channel, and relates to the technical field of freeze-thaw cycle test devices, including a frost heave body storage bin, wherein a plurality of temperature sensors are evenly arranged at intervals from bottom to top at the axis of the frost heave body storage bin; a simulated lining, wherein the frost heave body storage bin below the simulated lining is filled with a frost heave soil layer, and an axial displacement monitoring device is used to detect the axial displacement of the simulated lining; by pumping freeze-thaw medium into the medium storage bin, the freeze-thaw medium exchanges heat with the frost heave body storage bin above, thereby causing the frost heave soil layer to undergo frost heave changes. The present invention replaces the traditional precast concrete lining structure with a simulated lining, and the simulated lining can be used repeatedly, and can further simulate concrete of different strength grades, thereby greatly reducing the consumption of raw materials, being fast, efficient, energy-saving and environmentally friendly; and at the same time, the existing scattered structures are integrated, thereby reducing the occupied space.

Description

Technical Field

[0001] The invention relates to the technical field of freeze-thaw cycle test devices, in particular to a frost heave strain test device for a concrete lined channel. Background Art

[0002] In a cold environment, the temperature difference between the lining concrete and the soil at the bottom of the channel will cause the soil to freeze at low temperatures to form a permafrost layer. During the frost heave process, the soil will exert frost heave force on the lining, which may cause the lining to bulge or crack, triggering frost heave damage.

[0003] However, the existing test equipment has high requirements for the test environment, lacks the flexibility of environmental parameters, and is difficult to simulate the actual engineering environment, which limits its application in lining engineering. At present, the existing frost heave strain measurement technology in the field of lining engineering also lacks quantitative analysis of the temperature transfer process inside the lined channel.

[0004] To this end, a device and method for temperature conduction and frost heave strain of a concrete lined channel with a publication number of "CN114636729A" in the prior art includes: a frost heave device, which includes a lined channel body and a temperature control device, and the temperature control device is used to provide a predetermined temperature for the lined channel body; a detection device, which includes a lateral deformation detection device, a vertical deformation detection device and a plurality of temperature sensors; the lateral deformation detection device is used to detect the lateral frost heave strain parameters of the lined channel body; a plurality of temperature sensors are arranged along the axial direction of the lined channel body and embedded in the interior of the lined channel body, and are used to detect the temperature conduction performance of the lined channel body. The present invention can achieve the technical effect of quantitatively analyzing the internal temperature conduction process of the lined channel body and measuring the concrete lining plate and the channel foundation soil as a whole.

[0005] However, the above-mentioned device still has obvious defects during use: the above-mentioned device and the lining frost heave test device in the prior art usually require prefabrication of concrete lining. Since concrete cannot be reused after solidification and hardening modification, it is discarded after use, which has caused a large amount of waste of raw materials in the long run. In addition, the solidification and hardening time of concrete is relatively long, so it is necessary to prefabricate concrete in advance, and it is difficult to conduct experiments quickly without an expected plan. In addition, concrete of different grades has large differences in physical parameters after solidification and hardening. Therefore, if experiments of different grades of concrete are required, it is necessary to produce multiple groups of concrete of different grades, which further causes waste of raw materials. In addition, the structure of the existing device is relatively independent, and the assembly combination of the components is relatively loose. Summary of the invention

[0006] The object of the present invention is to provide a concrete lined channel frost heave strain test device to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A frost heave strain experimental device for a concrete lined channel, comprising:

[0009] A frost heave body storage bin, wherein a plurality of temperature sensors are evenly spaced from bottom to top at the axis of the frost heave body storage bin;

[0010] A simulated lining, wherein the simulated lining is fixedly installed on the upper side of the frost heave body storage bin through a limiting device, the frost heave body storage bin below the simulated lining is filled with a frost heave soil layer, the simulated lining is composed of an inner ring, an outer ring and pre-tightening spokes, the two ends of the pre-tightening spokes are respectively connected to the inner ring and the outer ring, the inner ring is coaxially arranged with the outer ring, one end of the pre-tightening spoke located on the outer ring is connected to the spoke adjusting cap, and one end of the pre-tightening spoke located on the inner ring is also connected to the tension force sensor, and the tension strength of the pre-tightening spoke is changed by rotating the spoke adjusting cap;

[0011] An axial displacement monitoring device is used to abut against the upper surface of the inner ring. During the simulated freeze-thaw cycle, the volume change of the frost-heaving soil layer pushes the inner ring to produce axial displacement, and the axial displacement of the simulated lining is detected by the axial displacement monitoring device;

[0012] The bottom temperature-changing box, the frost-heaving body containing bin is fixedly installed on the bottom temperature-changing box, a medium containing bin is opened in the bottom temperature-changing box, freeze-thaw medium is pumped into the medium containing bin, and the freeze-thaw medium exchanges heat with the frost-heaving body containing bin above, thereby causing the frost-heaving soil layer to undergo frost-heaving changes.

[0013] Preferably, the limiting device includes an L-shaped fixing frame installed in a circular array on the outside of the frost heave body containing bin, and the L-shaped fixing frame is provided with an extrusion spring on the side close to the frost heave body containing bin, and the extrusion spring is connected to the telescopic limiting block at one end away from the L-shaped fixing frame, and the frost heave body containing bin and the outer ring are provided with corresponding limiting slots for accommodating the telescopic limiting blocks, and the limiting installation of the simulated lining in the frost heave body containing bin is completed by inserting the telescopic limiting blocks into the limiting slots.

[0014] Preferably, the outer ring is further provided with sealing grooves on the upper and lower sides of the limiting slot, and a sealing rubber ring is installed in the sealing groove.

[0015] Preferably, the upper portion of the inner ring is in a truncated cone shape, and the upper surface of the truncated cone-shaped inner ring is arranged flush with the upper surface of the outer ring.

[0016] Preferably, a gypsum reinforcement layer is cast between the inner ring and the outer ring of the simulated lining, and the upper and lower ends of the gypsum reinforcement layer are arranged flush with the upper and lower ends of the outer ring.

[0017] Preferably, the axial displacement monitoring device includes guide rails, a sliding frame and a detection probe arranged on both sides, the guide rails on both sides are parallel and fixedly mounted on the upper surface of the frost heave body containing bin, the sliding frame cooperates with the guide rails on both sides, the detection probe is fixedly mounted on the sliding frame, and during the detection process, the displacement probe of the detection probe abuts against the axis center of the inner ring, and the inner ring produces an axial displacement upward during the frost heave process, thereby pushing the displacement probe to produce displacement.

[0018] Preferably, a freeze-thaw medium inlet and a freeze-thaw medium outlet are also provided on the side of the bottom temperature variable box, and the freeze-thaw medium inlet and the freeze-thaw medium outlet are respectively connected to a circulation pump through pipelines, and the freeze-thaw medium is pumped into the medium containing bin through the circulation pump.

[0019] Preferably, a bottom temperature sensor is installed in the bottom temperature variable box.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention replaces the traditional prefabricated concrete lining structure with a simulated lining, which can be used repeatedly without a long waiting time for coagulation and hardening. It can also further simulate concrete of different strength grades, greatly reducing the consumption of raw materials. The experimental process is no longer limited by the coagulation and hardening time of concrete, and is fast, efficient, energy-saving and environmentally friendly.

[0022] The present invention integrates the existing scattered structures, thereby making the device more compact and the connections between the devices tighter, thereby reducing the occupied space and facilitating subsequent maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a three-dimensional schematic diagram of the overall structure of the present invention;

[0024] Figure 2 It is a three-dimensional schematic diagram of the cross-sectional structure of the present invention;

[0025] Figure 3 It is a schematic plan view of the cross-sectional structure of the present invention;

[0026] Figure 4 It is a schematic top view of the overall structure of the present invention;

[0027] Figure 5 It is a three-dimensional schematic diagram of the simulated lining and limit device structure of the present invention.

[0028] In the figure: 1 frost heave body storage bin, 2 temperature sensor, 3 simulated lining, 4 inner ring, 5 outer ring, 6 pre-tightening spokes, 7 spoke adjustment caps, 8 bottom temperature variable box, 9 medium storage bin, 10 L-shaped fixing frame, 11 extrusion spring, 12 telescopic limit block, 13 limit slot, 14 sealing rubber ring, 15 guide rail, 16 sliding frame, 17 detection probe, 18 freeze-thaw medium inlet, 19 freeze-thaw medium outlet, 20 bottom temperature sensor. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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.

[0030] See also Figure 1-5 , the present invention provides a technical solution:

[0031] Embodiment 1:

[0032] A frost heave strain experimental device for a concrete lined channel, comprising:

[0033] A frost heave body storage bin 1, wherein a plurality of temperature sensors 2 are evenly arranged at intervals from bottom to top at the axis of the frost heave body storage bin 1;

[0034] A simulated lining 3 is fixedly installed on the upper side of the frost heave body storage bin 1 through a limiting device. The frost heave body storage bin 1 below the simulated lining 3 is filled with a frost heave soil layer. The simulated lining 3 is composed of an inner ring 4, an outer ring 5 and a pre-tightening spoke 6. The two ends of the pre-tightening spoke 6 are respectively connected to the inner ring 4 and the outer ring 5. The inner ring 4 and the outer ring 5 are coaxially arranged. The pre-tightening spoke 6 is located at one end of the outer ring 5 and is connected to the spoke adjusting cap 7. The pre-tightening spoke 6 is located at one end of the inner ring 4 and is also connected to the tension force sensor. The tension strength of the pre-tightening spoke 6 is changed by rotating the spoke adjusting cap.

[0035] An axial displacement monitoring device is used to abut against the upper surface of the inner ring 4. During the simulated freeze-thaw cycle, the volume change of the frost-heaving soil layer pushes the inner ring 4 to generate an axial displacement. The axial displacement of the simulated lining 3 is detected by the axial displacement monitoring device.

[0036] The bottom temperature-changing box 8 and the frost-heaving body containing bin 1 are fixedly installed on the bottom temperature-changing box 8. A medium containing bin 9 is opened in the bottom temperature-changing box 8. By pumping freeze-thaw medium into the medium containing bin 9, the freeze-thaw medium exchanges heat with the frost-heaving body containing bin 1 above, thereby causing the frost-heaving soil layer to undergo frost-heaving changes.

[0037] In this embodiment, the bottom of the frost heave body storage bin 1 is used to fill the frost heave soil layer, so as to simulate the expansion-contraction process of the soil in the river channel during the freeze-thaw cycle. The simulated lining 3 is arranged next to the frost heave soil layer. A temperature sensor 2 is arranged from bottom to top at the axis of the frost heave body storage bin 1. The frost heave depth can be detected by the setting of the temperature sensor 2. The lining in the prior art usually adopts a precast concrete structure to simulate the concrete lining structure in the river channel. However, the simulated lining 3 in this embodiment is composed of an inner ring 4, an outer ring 5 and pre-tightening spokes 6, and its structure is similar to that of a spoke wheel. The pre-tightening spokes 6 are pulled mutually so that The simulated lining 3 has high strength. The design of the structure is used to simulate the frost heave changes of the concrete lining, which can greatly reduce the use of concrete raw materials. The structure can be used repeatedly, which is more energy-saving and environmentally friendly. The pre-tightening spoke 6 is located at one end of the outer ring 5 and is connected to the spoke adjustment cap 7. Its structure is also similar to the pre-tightening structure on the spoke wheel. The tensile strength of the pre-tightening spoke 6 is adjusted by rotating the spoke adjustment cap 7, thereby changing the strength of the simulated lining 3. The significance of this setting is to simulate concrete linings with different compressive strengths, so that the simulated lining 3 can simulate concrete of different strengths, and through The tension sensor makes the tension value of each pre-tightened spoke 6 within the required range, thereby ensuring uniform tension strength in each part. During use, in order to further simulate the concrete structure, a gypsum reinforcement layer is cast between the inner ring 4 and the outer ring 5, and the upper and lower ends of the gypsum reinforcement layer are flush with the upper and lower ends of the outer ring 5. Since the coagulation and hardening time of gypsum is much lower than the coagulation and hardening time of cement, and the cost of gypsum is lower, the setting of gypsum can highly simulate the state of concrete after coagulation and hardening. When the frozen heave soil layer at the bottom of the frost heave body storage bin 1 freezes and heaves, the frozen heave body storage bin 1 constrains the radial The frost heave process is simulated, and the outer ring 5 of the simulated lining 3 also constrains the edge position of the frost heave soil layer. Therefore, the frost heave soil layer will bulge toward the axis of the frost heave body storage bin 1 in a mound-like manner when frost heave occurs, and the bulge usually forms the highest point near the axis of the frost heave body storage bin 1. Therefore, the frost heave soil layer will push the preloaded spokes 6 and the inner ring 4 to axially displace upward, and the displacement is more obvious than the unconstrained radial displacement. At this time, the axial displacement change can be obtained by measuring the displacement of the inner ring 4. At the same time, combined with the temperature sensor 2 set in the frost heave body storage bin 1, the frost heave depth at this time can be known. The actual frost heave force distribution of the test point is obtained, and this point is the position where the frost heave force is the largest, wherein P(x) is the normal frost heave force on each point of the simulated lining 3, S(x) is the change in vertical displacement of the lining, H(x) is the frozen depth of the base soil, and Ef is the dynamic elastic modulus of the base soil. A bottom temperature-changing box 8 is also provided at the bottom of the frost heave body storage bin 1, and the medium storage bin 9 of the bottom temperature-changing box 8 is used to pump freeze-thaw cycle medium. For example, when it is necessary to freeze the soil layer, low-temperature gas is pumped into the medium storage bin 9. After entering the medium storage bin 9, the gas exchanges heat with the frost heave body storage bin 1 through heat transfer, thereby promoting frost heave from bottom to top. When it is necessary to melt the frozen heave soil layer, warm water is pumped into the medium storage bin 9, so that the soil layer in the frost heave body storage bin 1 can be quickly melted, and the freeze-thaw cycle process is regulated by the release of low-temperature gas and warm water.

[0038] Embodiment 2:

[0039] The limiting device includes an L-shaped fixing frame 10 installed in a circular array on the outside of the frost heave body containing bin 1. The L-shaped fixing frame 10 is installed with an extrusion spring 11 on the side close to the frost heave body containing bin 1. The end of the extrusion spring 11 away from the L-shaped fixing frame 10 is connected to the telescopic limiting block 12. The frost heave body containing bin 1 and the outer ring 5 are correspondingly provided with limiting slots 13 for accommodating the telescopic limiting block 12. By inserting the telescopic limiting block 12 into the limiting slot 13, the limiting installation of the simulated lining 3 in the frost heave body containing bin is completed.

[0040] Preferably, the outer ring 5 is further provided with sealing grooves at the upper and lower sides of the limiting slot 13, and a sealing rubber ring 14 is installed in the sealing groove.

[0041] The upper part of the inner ring 4 is in a truncated cone shape, and the upper surface of the truncated cone-shaped inner ring 4 is arranged flush with the upper surface of the outer ring 5 .

[0042] In this embodiment, the installation and limiting device of the simulated lining 3 is further disclosed. The outer diameter of the outer ring 5 of the simulated lining 3 is slightly smaller than the inner diameter of the frost heave body containing bin 1, and the edge position is sealed by a sealing rubber ring 14. The telescopic limit block 12 is inserted into the limit slot 13, thereby realizing the limited installation of the simulated lining 3 in the frost heave body containing bin 1. At the same time, the upper part of the inner ring 4 is in a truncated cone shape, so that it can protrude from the surface of the gypsum, so that the displacement probe can abut against the upper surface of the inner ring 4, thereby accurately detecting the axial displacement.

[0043] Embodiment three:

[0044] The axial displacement monitoring device includes guide rails 15, a sliding frame 16 and a detection probe 17 arranged on both sides. The guide rails 15 on both sides are parallel and fixedly installed on the upper surface of the frost heave body storage bin 1, and the sliding frame 16 cooperates with the guide rails 15 on both sides. The detection probe 17 is fixedly installed on the sliding frame 16. During the detection process, the displacement probe of the detection probe 17 abuts against the axis center of the inner ring 4. The inner ring 4 produces an axial displacement upward during the frost heave process, thereby pushing the displacement probe to produce displacement.

[0045] In this embodiment, the specific structure of the axial displacement monitoring device is further disclosed. It is connected to the frost heave body containing bin 1 so that it does not need to occupy more space and is more tightly connected to the main device to prevent it from being missed or lost during later use. The translational sliding of the sliding frame 16 does not hinder the loading of the simulated lining 3.

[0046] Embodiment 4:

[0047] A freeze-thaw medium inlet 18 and a freeze-thaw medium outlet 19 are also provided on the side of the bottom temperature-changing box 8 .

[0048] A bottom temperature sensor 20 is installed in the bottom temperature changing box 8 .

[0049] In this embodiment, the specific structure of the bottom temperature variable box 8 is further disclosed. The freeze-thaw medium can enter the medium containing chamber 9 and can flow and circulate through the freeze-thaw medium inlet 18 and the freeze-thaw medium outlet 19. The temperature of the medium containing chamber 9 is detected by the bottom temperature sensor 20. The freeze-thaw medium inlet 18 and the freeze-thaw medium outlet 19 are respectively connected to the circulation pump through pipelines, and the freeze-thaw medium is pumped into the medium containing chamber 9 by the circulation pump.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, tension force sensors and variations may be made to the embodiments without departing from the principles and spirit of the invention, the scope of the invention being defined by the appended claims and their equivalents.

Claims

1. A concrete lined channel frost heave strain test device, characterized in that: include: A frost heave body storage bin, wherein a plurality of temperature sensors are evenly spaced from bottom to top at the axis of the frost heave body storage bin; A simulated lining, wherein the simulated lining is fixedly installed on the upper side of the frost heave body storage bin through a limiting device, the frost heave body storage bin below the simulated lining is filled with a frost heave soil layer, the simulated lining is composed of an inner ring, an outer ring and pre-tightening spokes, the two ends of the pre-tightening spokes are respectively connected to the inner ring and the outer ring, the inner ring is coaxially arranged with the outer ring, one end of the pre-tightening spoke located on the outer ring is connected to the spoke adjusting cap, and one end of the pre-tightening spoke located on the inner ring is also connected to the tension force sensor, and the tension strength of the pre-tightening spoke is changed by rotating the spoke adjusting cap; An axial displacement monitoring device is used to abut against the upper surface of the inner ring. During the simulated freeze-thaw cycle, the volume change of the frost-heaving soil layer pushes the inner ring to produce axial displacement, and the axial displacement of the simulated lining is detected by the axial displacement monitoring device; The bottom temperature-changing box, the frost-heaving body containing bin is fixedly installed on the bottom temperature-changing box, a medium containing bin is opened in the bottom temperature-changing box, freeze-thaw medium is pumped into the medium containing bin, and the freeze-thaw medium exchanges heat with the frost-heaving body containing bin above, thereby causing the frost-heaving soil layer to undergo frost-heaving changes.

2. A concrete lined channel frost heave strain test device according to claim 1, characterized in that: The limiting device includes an L-shaped fixing frame installed in a circular array on the outside of the frost heave body containing bin, and the L-shaped fixing frame is installed with an extrusion spring on the side close to the frost heave body containing bin, and the extrusion spring is connected to the telescopic limiting block at one end away from the L-shaped fixing frame. The frost heave body containing bin and the outer ring are correspondingly provided with limiting slots for accommodating the telescopic limiting blocks, and the limiting installation of the simulated lining in the frost heave body containing bin is completed by inserting the telescopic limiting blocks into the limiting slots.

3. A concrete lined channel frost heave strain test device according to claim 2, characterized in that: The outer ring is also provided with sealing grooves on the upper and lower sides of the limiting slot, and a sealing rubber ring is installed in the sealing groove.

4. A concrete lined channel frost heave strain test device according to claim 2, characterized in that: The upper part of the inner ring is in a truncated cone shape, and the upper surface of the truncated cone-shaped inner ring is arranged flush with the upper surface of the outer ring.

5. A concrete lined channel frost heave strain test device according to claim 2 or 4, characterized in that: A gypsum reinforcement layer is also cast between the inner ring and the outer ring of the simulated lining, and the upper and lower ends of the gypsum reinforcement layer are arranged flush with the upper and lower ends of the outer ring.

6. A concrete lined channel frost heave strain test device according to claim 5, characterized in that: The axial displacement monitoring device includes guide rails, a sliding frame and a detection probe arranged on both sides. The guide rails on both sides are parallel and fixedly installed on the upper surface of the frost heave body containing bin. The sliding frame cooperates with the guide rails on both sides. The detection probe is fixedly installed on the sliding frame. During the detection process, the displacement probe of the detection probe abuts against the axis center of the inner ring. The inner ring produces an axial displacement upward during the frost heave process, thereby pushing the displacement probe to produce displacement.

7. A concrete lined channel frost heave strain test device according to claim 6, characterized in that: The side of the bottom temperature variable box is also provided with a freeze-thaw medium inlet and a freeze-thaw medium outlet, which are respectively connected to a circulation pump through pipelines, and the freeze-thaw medium is pumped into the medium containing bin through the circulation pump.

8. A concrete lined channel frost heave strain test device according to claim 7, characterized in that: A bottom temperature sensor is installed in the bottom temperature variable box.

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