Suitable giant span cavern single-layer lining support negative poisson's ratio intelligent anchor rod and construction method
By designing a negative Poisson's ratio smart anchor in a giant-span tunnel, combined with a hollow grouting rod body and a force sensing unit, effective monitoring and force sensing of axial loads were achieved, solving the problem of anchor monitoring in giant-span tunnels and taking into account both load-bearing and deformation requirements.
Patent Information
- Application Number
- CN202611528713.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-30
- Publication Date
- 2026-11-03
AI Technical Summary
Existing anchor bolts are difficult to effectively monitor axial loads in large-span tunnels. Traditional monitoring methods are greatly affected by construction disturbances. Negative Poisson's ratio structural designs cannot take into account both load-bearing capacity and free deformation. Furthermore, grouting construction affects the force perception effect.
A negative Poisson's ratio smart anchor bolt suitable for giant-span tunnels is designed. It combines a hollow grouting rod body, a negative Poisson's ratio force sensing unit, a micro data acquisition module, and an intelligent monitoring and early warning instrument. It monitors load transfer and force sensing by converting axial load into radial deformation.
It achieves effective load transfer and stress sensing in giant-span tunnels, taking into account normal anchorage bearing, continuous grouting and free deformation of negative Poisson's ratio structures, and provides intelligent monitoring functions.
Smart Images
Figure CN123028049A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of underground engineering support structure and intelligent monitoring technology, and in particular relates to a negative Poisson's ratio intelligent anchor rod and construction method applicable to single-layer lining support of giant span caverns. Background Technology
[0002] With the rapid development of large-scale underground space projects such as underground energy storage and underground water-sealed caverns, the span of underground caverns is also constantly increasing. After the excavation of a mega-span underground cavern, the stress redistribution of the surrounding rock is significant, and areas such as the arch crown, arch shoulders, and sidewalls are prone to varying degrees of surrounding rock deformation and stress concentration. Therefore, mega-span caverns require a combined support system formed by anchor bolts, shotcrete, and lining structures.
[0003] Hollow grouting anchors are widely used in underground cavern support due to their combined anchoring and grouting functions. Traditional hollow grouting anchors mainly serve to reinforce the surrounding rock and transfer loads, but during service, the actual axial force and its changes inside the anchor are usually difficult to obtain directly.
[0004] Existing anchor bolt stress monitoring typically requires additional strain gauges, fiber optic sensors, or force measuring devices, but these are easily affected by factors such as monitoring location, wiring conditions, construction disturbances, and localized stress concentrations. Furthermore, traditional anchor bolts exhibit relatively small radial deformation during axial tension, making it difficult to directly characterize axial loads using radial deformation in complex underground engineering environments.
[0005] Negative Poisson's ratio structures are a special type of structure that can produce radial expansion deformation under axial tension. If negative Poisson's ratio structures are introduced into the design of hollow grouting anchors, the conditions for converting the axial load of the anchor into measurable radial expansion deformation can be met. By establishing the calibration relationship between radial deformation and axial load, the needs of load transfer and force perception can be satisfied.
[0006] However, in existing anchor bolt designs incorporating negative Poisson's ratio structures, these structures are mostly energy-absorbing components, which cannot meet the aforementioned stress sensing requirements. Simply designing the entire hollow grouting anchor bolt as a negative Poisson's ratio structure would not only reduce the overall load-bearing capacity of the anchor bolt but also increase the processing difficulty. Furthermore, during grouting, if the grout enters the pores of the negative Poisson's ratio structure, it would severely restrict its free deformation, thus affecting the stress sensing effect. And there are no mature technologies available for reference in existing anchor bolt designs incorporating negative Poisson's ratio structures.
[0007] Therefore, it is imperative to develop a new type of anchor bolt solution that can take into account normal anchorage bearing capacity, continuous grouting, free deformation of negative Poisson's ratio structure, and intelligent monitoring functions. Summary of the Invention
[0008] To address the problems existing in the prior art, this invention provides a negative Poisson's ratio intelligent anchor rod and construction method applicable to single-layer lining support of giant-span tunnels. By introducing the negative Poisson's ratio structure into the design of the hollow grouting anchor rod, the needs of load transfer and stress sensing are met. The overall solution can effectively take into account normal anchorage bearing capacity, continuous grouting, free deformation of the negative Poisson's ratio structure, and intelligent monitoring function.
[0009] To achieve the above objectives, the present invention adopts the following technical solution: a negative Poisson's ratio intelligent anchor bolt suitable for single-layer lining support in large-span tunnels, comprising a hollow grouting rod body, a negative Poisson's ratio force sensing unit, a micro data acquisition module, an intelligent monitoring and early warning instrument, a tray, and a nut; the hollow grouting rod body and the negative Poisson's ratio force sensing unit are coaxially connected in series; the micro data acquisition module is fixedly installed on the inner wall surface of the hollow grouting rod body; the tray and nut are sequentially installed on the extended section of the hollow grouting rod outside the anchor hole; the intelligent monitoring and early warning instrument is fixedly installed at the end of the extended section of the hollow grouting rod; the negative Poisson's ratio force sensing unit is electrically connected to the intelligent monitoring and early warning instrument through the micro data acquisition module.
[0010] The negative Poisson's ratio force sensing unit includes a negative Poisson's ratio structural cylinder and strain gauges; the strain gauges are fixedly attached to the outer surface of the negative Poisson's ratio structural cylinder, and the strain gauges are connected to a micro data acquisition module via wires; the negative Poisson's ratio structural cylinder is coaxially and fixedly connected to the hollow grouting rod.
[0011] The strain gauges are arranged at least once along the axial direction of the negative Poisson's ratio structure cylinder, and the strain gauges at each location are evenly distributed along the circumference of the negative Poisson's ratio structure cylinder.
[0012] A plurality of concave hexagonal holes are provided on the negative Poisson's ratio structure cylinder, and the line connecting the concave corner points of the concave hexagonal holes is parallel to the axial direction of the negative Poisson's ratio structure cylinder.
[0013] The concave hexagonal holes are evenly distributed in the circumferential direction of the negative Poisson's ratio structure cylinder, and the concave hexagonal holes are distributed in a linear array in the axial direction of the negative Poisson's ratio structure cylinder.
[0014] An epoxy resin protective sleeve is wrapped around the outside of the negative Poisson's ratio structure cylinder, and the strain gauge is located between the epoxy resin protective sleeve and the outer wall surface of the negative Poisson's ratio structure cylinder.
[0015] A flexible grouting guide pipe is coaxially installed inside the negative Poisson's ratio structure cylinder, and both ends of the flexible grouting guide pipe are respectively inserted into the grouting channel of the adjacent hollow grouting rod.
[0016] The miniature data acquisition module includes a housing, a Wheatstone bridge, a signal amplifier, and a digital-to-analog converter. The Wheatstone bridge, signal amplifier, and digital-to-analog converter are all sealed and fixedly mounted inside the housing, which is fixedly connected to the inner wall of the hollow grouting rod. The input terminal of the Wheatstone bridge is electrically connected to the strain gauge via a wire, the output terminal of the Wheatstone bridge is electrically connected to the input terminal of the signal amplifier, the output terminal of the signal amplifier is electrically connected to the input terminal of the digital-to-analog converter, and the output terminal of the digital-to-analog converter is electrically connected to the intelligent monitoring and early warning instrument via a wire.
[0017] When the negative Poisson's ratio structure cylinder is subjected to axial force, the strain generated during the radial deformation of the negative Poisson's ratio structure cylinder is denoted as... e t The axial force borne by the negative Poisson's ratio cylindrical structure is denoted as... N ,and N=k D e t ;in, k D It is the equivalent conversion coefficient between radial strain and axial force of a negative Poisson's ratio cylindrical structure, which is obtained through experimental calibration.
[0018] A construction method employing the aforementioned negative Poisson's ratio intelligent anchor bolt suitable for single-layer lining support in mega-span tunnels includes the following steps: Step 1: After the shotcrete layer of the giant span tunnel is completed, drilling of anchor holes is carried out at the pre-designated locations in the surrounding rock. Step 2: Based on the depth and diameter of the anchoring hole, select the matching hollow grouting rod and negative Poisson's ratio force sensing unit and assemble them in series to form the anchor rod body; Step 3: Insert the assembled anchor body into the anchor hole, and then connect the anchor body to the grouting equipment; Step 4: Start the grouting equipment. The grout enters the anchor hole through the grouting channel in the center of the anchor body until the space between the anchor body and the anchor hole is filled with grout. Step 5: After the grout between the anchor body and the anchor hole reaches the preset curing strength, install the tray and nut onto the hollow grouting rod extension of the anchor body, and then tighten the nut to complete the application of pre-tightening force to the anchor body. Step Six: First, connect the external wire of the micro data acquisition module to the access wire of the intelligent monitoring and early warning instrument, and then fix the intelligent monitoring and early warning instrument to the end of the hollow grouting rod extension of the anchor body; Step 7: Complete the construction of a single-layer lining outside the shotcrete layer until the anchor bolts, shotcrete, and lining form a combined support system; Step 8: Once the combined support system enters the service phase, the axial force monitored by the negative Poisson's ratio force sensing unit will be transferred to the system. N The data is fed back in real time to the intelligent monitoring and early warning instrument, which has a pre-set axial force alarm threshold. N w ,when N≥N w At that time, an alarm signal will be issued by the intelligent monitoring and early warning instrument.
[0019] The beneficial effects of this invention are: The present invention relates to a negative Poisson's ratio intelligent anchor rod and construction method applicable to single-layer lining support of large-span tunnels. By introducing a negative Poisson's ratio structure into the design of hollow grouting anchor rods, it meets the needs of load transfer and stress sensing. The overall scheme can effectively take into account normal anchorage bearing capacity, continuous grouting, free deformation of negative Poisson's ratio structure, and intelligent monitoring function. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of a negative Poisson's ratio smart anchor rod applicable to single-layer lining support of mega-span tunnels according to the present invention; Figure 2 This is a schematic diagram of the negative Poisson's ratio force sensing unit of the present invention; Figure 3 for Figure 2 Sectional view of AA in the middle; Figure 4 This is a schematic diagram of the structure of the miniature data acquisition module of the present invention; In the figure, 1—hollow grouting rod, 2—negative Poisson's ratio force sensing unit, 3—micro data acquisition module, 4—intelligent monitoring and early warning instrument, 5—tray, 6—nut, 7—negative Poisson's ratio structural cylinder, 8—strain gauge, 9—concave hexagonal hole, 10—epoxy resin protective sleeve, 11—flexible grouting guide pipe, 12—encapsulation shell, 13—Wheatstone bridge, 14—signal amplifier, 15—digital-to-analog converter. Detailed Implementation
[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0022] like Figure 1~Figure 4As shown, a negative Poisson's ratio intelligent anchor bolt suitable for single-layer lining support of large-span tunnels includes a hollow grouting rod body 1, a negative Poisson's ratio force sensing unit 2, a micro data acquisition module 3, an intelligent monitoring and early warning instrument 4, a tray 5, and a nut 6. The hollow grouting rod body 1 and the negative Poisson's ratio force sensing unit 2 are coaxially connected in series. The micro data acquisition module 3 is fixedly installed on the inner wall surface of the hollow grouting rod body 1. The tray 5 and the nut 6 are sequentially installed on the extended section of the hollow grouting rod body 1 outside the anchor hole. The intelligent monitoring and early warning instrument 4 is fixedly installed at the end of the extended section of the hollow grouting rod body 1. The negative Poisson's ratio force sensing unit 2 is electrically connected to the intelligent monitoring and early warning instrument 4 through the micro data acquisition module 3.
[0023] The negative Poisson's ratio force sensing unit 2 includes a negative Poisson's ratio structural cylinder 7 and a strain gauge 8; the strain gauge 8 is fixedly attached to the outer surface of the negative Poisson's ratio structural cylinder 7, and the strain gauge 8 is connected to the micro data acquisition module 3 through a wire; the negative Poisson's ratio structural cylinder 7 is coaxially and fixedly connected to the hollow grouting rod 1.
[0024] The strain gauge 8 is arranged at least once in the axial direction of the negative Poisson's ratio structure cylinder 7, and the strain gauge 8 at each location is evenly distributed along the circumference of the negative Poisson's ratio structure cylinder 7.
[0025] A plurality of concave hexagonal holes 9 are provided on the negative Poisson's ratio structure cylinder 7, and the line connecting the concave corner points of the concave hexagonal holes 9 is parallel to the axial direction of the negative Poisson's ratio structure cylinder 7.
[0026] The concave hexagonal holes 9 are evenly distributed in the circumferential direction of the negative Poisson's ratio structure cylinder 7, and the concave hexagonal holes 9 are distributed in a linear array in the axial direction of the negative Poisson's ratio structure cylinder 7.
[0027] An epoxy resin protective sleeve 10 is wrapped around the outside of the negative Poisson's ratio structure cylinder 7, and the strain gauge 8 is located between the epoxy resin protective sleeve 10 and the outer wall surface of the negative Poisson's ratio structure cylinder 7.
[0028] A flexible grouting guide pipe 11 is coaxially installed inside the negative Poisson's ratio structure cylinder 7, and the two ends of the flexible grouting guide pipe 11 are respectively inserted into the grouting channel of the adjacent hollow grouting rod 1.
[0029] The micro data acquisition module 3 includes a housing 12, a Wheatstone bridge 13, a signal amplifier 14, and a digital-to-analog converter 15. The Wheatstone bridge 13, the signal amplifier 14, and the digital-to-analog converter 15 are all sealed and fixedly installed in the housing 12, and the housing 12 is fixedly connected to the inner wall of the hollow grouting rod 1. The input end of the Wheatstone bridge 13 is electrically connected to the strain gauge 8 through a wire, the output end of the Wheatstone bridge 13 is electrically connected to the input end of the signal amplifier 14, the output end of the signal amplifier 14 is electrically connected to the input end of the digital-to-analog converter 15, and the output end of the digital-to-analog converter 15 is electrically connected to the intelligent monitoring and early warning instrument 4 through a wire.
[0030] When the negative Poisson's ratio structure cylinder 7 is subjected to axial force, the strain generated during the radial deformation of the negative Poisson's ratio structure cylinder 7 is denoted as... e t The axial force borne by the negative Poisson's ratio cylindrical body 7 is denoted as... N ,and N=k D e t ;in, k D is the equivalent conversion coefficient between radial strain and axial force for the negative Poisson's ratio cylindrical structure 7, which is obtained through experimental calibration.
[0031] Specifically, the equivalent conversion factor between radial strain and axial force for the negative Poisson's ratio cylindrical structure 7. k D The experimental calibration method is as follows: the negative Poisson's ratio structure cylinder 7 is clamped between the upper and lower clamps of the universal tensile testing machine. Then, axial force is applied to the negative Poisson's ratio structure cylinder 7 step by step, and the strain value of radial deformation under each axial force load is recorded. Then, the axial force is used as the abscissa and the strain is used as the ordinate. The obtained discrete data points are then fitted into a line. Finally, arbitrary strain is inverted based on the fitted line. e t Corresponding axial force N and through N / e t Get what you need k D value.
[0032] In this embodiment, one negative Poisson's ratio force sensing unit 2 is deployed, which is connected between two hollow grouting rods 1. The hollow grouting rod 1 is made of high-strength alloy steel, and the negative Poisson's ratio structural cylinder 7 is made of 316L stainless steel. The concave hexagonal hole 9 is prepared on the negative Poisson's ratio structural cylinder 7 by laser cutting. The negative Poisson's ratio structural cylinder 7 and the hollow grouting rod 1 are connected by screws. The flexible grouting guide pipe 11 is made of rubber or polymer material and should have good pressure resistance and corrosion resistance. The stiffness of the flexible grouting guide pipe 11 needs to be lower than the stiffness of the negative Poisson's ratio structural cylinder 7. The strain gauge 8 is a resistive strain sensor, and there are four strain gauges 8 at the same axial position. The radial strain of the negative Poisson's ratio structural cylinder 7 is measured. e t Take the average value of all 8 measured values of the strain gauges.
[0033] A construction method employing the aforementioned negative Poisson's ratio intelligent anchor bolt suitable for single-layer lining support in mega-span tunnels includes the following steps: Step 1: After the shotcrete layer of the giant span tunnel is completed, drilling of anchor holes is carried out at the pre-designated locations in the surrounding rock. Step 2: Based on the depth and diameter of the anchoring hole, select the matching hollow grouting rod body 1 and negative Poisson's ratio force sensing unit 2 and assemble them in series to form the anchor rod body; Step 3: Insert the assembled anchor body into the anchor hole, and then connect the anchor body to the grouting equipment; Step 4: Start the grouting equipment. The grout enters the anchor hole through the grouting channel in the center of the anchor body until the space between the anchor body and the anchor hole is filled with grout. Step 5: After the grout between the anchor body and the anchor hole reaches the preset curing strength, install the tray 5 and nut 6 onto the extended section of the hollow grouting rod 1 of the anchor body, and then tighten the nut 6 to complete the application of the pre-tightening force of the anchor body. Step 6: First, connect the external wire of the micro data acquisition module 3 to the access wire of the intelligent monitoring and early warning instrument 4, and then fix the intelligent monitoring and early warning instrument 4 to the end of the hollow grouting rod body 1 of the anchor bolt body. Step 7: Complete the construction of a single-layer lining outside the shotcrete layer until the anchor bolts, shotcrete, and lining form a combined support system; Step 8: Once the combined support system enters the service phase, the axial force monitored by the negative Poisson's ratio force sensing unit 2 will be transmitted. N The data is fed back in real time to the intelligent monitoring and early warning instrument 4, which has a pre-set axial force alarm threshold. N w ,when N≥Nw At that time, the intelligent monitoring and early warning instrument 4 will issue an alarm signal.
[0034] Specifically, N w =ηN y In the formula, N y This is the maximum axial yield bearing capacity of the anchor bolt body, which can be obtained through experiments; or In this embodiment, the warning coefficient is used as the early warning factor. or The value is 0.8.
[0035] The solutions in the embodiments are not intended to limit the scope of protection of the present invention. All equivalent implementations or modifications that do not depart from the present invention are included in the scope of protection of the present invention.
Claims
1. A negative Poisson's ratio intelligent anchor bolt suitable for single-layer lining support of mega-span tunnels, characterized in that: The device includes a hollow grouting rod, a negative Poisson's ratio force sensing unit, a micro data acquisition module, an intelligent monitoring and early warning instrument, a tray, and a nut. The hollow grouting rod and the negative Poisson's ratio force sensing unit are coaxially connected in series. The micro data acquisition module is fixedly installed on the inner wall of the hollow grouting rod. The tray and nut are sequentially installed on the extended section of the hollow grouting rod outside the anchor hole. The intelligent monitoring and early warning instrument is fixedly installed at the end of the extended section of the hollow grouting rod. The negative Poisson's ratio force sensing unit is electrically connected to the intelligent monitoring and early warning instrument through the micro data acquisition module.
2. The negative Poisson's ratio intelligent anchor bolt applicable to single-layer lining support of mega-span tunnels according to claim 1, characterized in that: The negative Poisson's ratio force sensing unit includes a negative Poisson's ratio structural cylinder and strain gauges; the strain gauges are fixedly attached to the outer surface of the negative Poisson's ratio structural cylinder, and the strain gauges are connected to a micro data acquisition module via wires; the negative Poisson's ratio structural cylinder is coaxially and fixedly connected to the hollow grouting rod.
3. The negative Poisson's ratio intelligent anchor bolt applicable to single-layer lining support of mega-span tunnels according to claim 2, characterized in that: The strain gauges are arranged at least once along the axial direction of the negative Poisson's ratio structure cylinder, and the strain gauges at each location are evenly distributed along the circumference of the negative Poisson's ratio structure cylinder.
4. The negative Poisson's ratio intelligent anchor bolt applicable to single-layer lining support of mega-span tunnels according to claim 3, characterized in that: A plurality of concave hexagonal holes are provided on the negative Poisson's ratio structure cylinder, and the line connecting the concave corner points of the concave hexagonal holes is parallel to the axial direction of the negative Poisson's ratio structure cylinder.
5. A negative Poisson's ratio intelligent anchor bolt applicable to single-layer lining support of mega-span tunnels according to claim 4, characterized in that: The concave hexagonal holes are evenly distributed in the circumferential direction of the negative Poisson's ratio structure cylinder, and the concave hexagonal holes are distributed in a linear array in the axial direction of the negative Poisson's ratio structure cylinder.
6. A negative Poisson's ratio intelligent anchor bolt applicable to single-layer lining support of mega-span tunnels according to claim 5, characterized in that: An epoxy resin protective sleeve is wrapped around the outside of the negative Poisson's ratio structure cylinder, and the strain gauge is located between the epoxy resin protective sleeve and the outer wall surface of the negative Poisson's ratio structure cylinder.
7. A negative Poisson's ratio intelligent anchor bolt applicable to single-layer lining support of mega-span tunnels according to claim 6, characterized in that: A flexible grouting guide pipe is coaxially installed inside the negative Poisson's ratio structure cylinder, and both ends of the flexible grouting guide pipe are respectively inserted into the grouting channel of the adjacent hollow grouting rod.
8. A negative Poisson's ratio intelligent anchor bolt applicable to single-layer lining support of mega-span tunnels according to claim 7, characterized in that: The miniature data acquisition module includes a housing, a Wheatstone bridge, a signal amplifier, and a digital-to-analog converter. The Wheatstone bridge, signal amplifier, and digital-to-analog converter are all sealed and fixedly mounted inside the housing, which is fixedly connected to the inner wall of the hollow grouting rod. The input terminal of the Wheatstone bridge is electrically connected to the strain gauge via a wire, the output terminal of the Wheatstone bridge is electrically connected to the input terminal of the signal amplifier, the output terminal of the signal amplifier is electrically connected to the input terminal of the digital-to-analog converter, and the output terminal of the digital-to-analog converter is electrically connected to the intelligent monitoring and early warning instrument via a wire.
9. A negative Poisson's ratio intelligent anchor bolt applicable to single-layer lining support of mega-span tunnels according to claim 8, characterized in that: When the negative Poisson's ratio structure cylinder is subjected to axial force, the strain generated during the radial deformation of the negative Poisson's ratio structure cylinder is denoted as... ε t The axial force borne by the negative Poisson's ratio cylindrical structure is denoted as... N ,and N=k D ε t ; in, k D It is the equivalent conversion coefficient between radial strain and axial force of a negative Poisson's ratio cylindrical structure, which is obtained through experimental calibration.
10. A construction method employing the negative Poisson's ratio intelligent anchor bolt for single-layer lining support of mega-span tunnels as described in claim 9, characterized in that... Includes the following steps: Step 1: After the shotcrete layer of the giant span tunnel is completed, drilling of anchor holes is carried out at the pre-designated locations in the surrounding rock. Step 2: Based on the depth and diameter of the anchoring hole, select the matching hollow grouting rod and negative Poisson's ratio force sensing unit and assemble them in series to form the anchor rod body; Step 3: Insert the assembled anchor body into the anchor hole, and then connect the anchor body to the grouting equipment; Step 4: Start the grouting equipment. The grout enters the anchor hole through the grouting channel in the center of the anchor body until the space between the anchor body and the anchor hole is filled with grout. Step 5: After the grout between the anchor body and the anchor hole reaches the preset curing strength, install the tray and nut onto the hollow grouting rod extension of the anchor body, and then tighten the nut to complete the application of pre-tightening force to the anchor body. Step Six: First, connect the external wire of the micro data acquisition module to the access wire of the intelligent monitoring and early warning instrument, and then fix the intelligent monitoring and early warning instrument to the end of the hollow grouting rod extension of the anchor body; Step 7: Complete the construction of a single-layer lining outside the shotcrete layer until the anchor bolts, shotcrete, and lining form a combined support system; Step 8: Once the combined support system enters the service phase, the axial force monitored by the negative Poisson's ratio force sensing unit will be transferred to the system. N The data is fed back in real time to the intelligent monitoring and early warning instrument, which has a pre-set axial force alarm threshold. N w ,when N≥N w At that time, an alarm signal will be issued by the intelligent monitoring and early warning instrument.