CN117988908B - A graded warning anchor rod and warning method based on liquid metal - Google Patents

Abstract

The invention discloses a grading early warning anchor rod based on liquid metal and an early warning method, and belongs to the field of fixed anchor rods, wherein the grading early warning anchor rod comprises a rod body, a fixing piece and an early warning device, one end of the rod body is anchored in a rock body, the other end of the rod body is sleeved with the early warning device and then connected with the fixing piece, and the fixing piece is used for fixing the early warning device on the rock body; the early warning device comprises a liquid bag with the inner diameter matched with the outer diameter of the rod body, a power supply, a circuit, an indicator light and a micro-channel, wherein the circuit comprises a main circuit and a branch circuit, the power supply is arranged on the main circuit, and the indicator light is arranged on the branch circuit; the liquid bag is made of elastic materials and stores liquid metal, an outlet of the liquid bag is communicated with the micro-flow channel, the liquid bag is extruded under the stress of the rod body, and the liquid metal fills the micro-flow channel and forms a conductive loop with the branch circuit to enable the indicator lamp to emit light. The grading early warning anchor rod has the advantages of simplicity, clarity and wide applicability, and has higher stability, safety and environmental protection.

Description

A graded warning anchor rod and warning method based on liquid metal

Technical Field

The present invention relates to the technical field of fixed anchor rods, and in particular to a liquid metal-based graded warning anchor rod and a warning method.

Background technique

With the acceleration of urbanization and the limited land resources, underground space has become an increasingly important space for urban development. Underground space can be used for projects and engineering such as building urban infrastructure, developing resources, and protecting the environment to improve the functions and service levels of the city. Therefore, the effective use of underground space has opened up new opportunities for urban development and promoted the sustainable development of cities. However, underground projects often have to deal with geological conditions with poor surrounding rock quality. In this context, anchor rods, as a common support and fixing structure, play an important role. Anchor rods can improve the stability and safety of underground structures and ensure the smooth progress of construction. When large deformation and displacement occur in underground projects, traditional anchor rods only provide support, but may be broken, which will lead to the destruction of the engineering rock and soil. Therefore, in order to timely understand the stress conditions and potential damage risks of anchor rods, it is necessary to develop early warning anchor rods to more effectively support underground engineering construction.

In the field of engineering materials, liquid metal has been widely used in many fields and has shown good development prospects due to its advantages such as good fluidity, conductivity, plasticity and corrosion resistance. For example, CN109339842A discloses a liquid metal sensor and a large deformation anchor rod using the sensor for monitoring and early warning. The liquid metal sensor includes an artificial skin, in which a microfluidic channel is made by soft lithography technology. The microfluidic channel is filled with liquid metal. The artificial skin is deformed according to the tension of the anchor rod, so that the resistance of the liquid metal in the microfluidic channel changes after being pulled. An early warning is given based on the measured resistance and the relationship between the experimental resistance and the tension. The early warning of this anchor rod is relatively reliable, but it requires resistance measurement and cannot directly reflect the stress conditions during the life cycle of the anchor rod.

Based on the characteristics of liquid metal, it is still necessary to construct an anchor with a simple structure and good early warning effect.

Summary of the invention

In view of the problems of the prior art, the present invention aims to solve the perception and early warning of the anchor rod damage process. The anchor rod of the present invention can not only provide support force, but also make full use of the fluidity and conductivity of liquid metal to realize the monitoring and early warning of the anchor rod, thereby ensuring the safety and stability of underground engineering construction.

In order to achieve the above-mentioned object, the present invention provides a liquid metal-based graded warning anchor rod, comprising a rod body, a fixing member and a warning device;

One end of the rod body is anchored in the rock mass, and the other end of the rod body is sleeved with the early warning device and then connected to the fixing piece, and the fixing piece fixes the early warning device on the rock mass;

The early warning device comprises a liquid capsule whose inner diameter matches the outer diameter of the rod, a power supply, a circuit, an indicator light and a microfluidic channel, wherein the circuit comprises a main circuit and a branch circuit, the power supply is arranged on the main circuit, and the branch circuit is provided with an indicator light;

The liquid capsule is made of elastic material and stores liquid metal. The outlet of the liquid capsule is connected to the microchannel. The rod body squeezes the liquid capsule under force, so that the liquid metal fills the microchannel and forms a conductive loop with the branch to make the indicator light up. As the force increases, the indicator lights of more branches light up.

Furthermore, the microchannel is divided into a plurality of regions according to the relationship between the extruded volume of the liquid metal and the pull-out resistance of the anchor rod;

When more areas of the microchannel are filled with liquid metal, more branches are connected and more branch indicator lights light up.

Furthermore, the relationship between the volume of liquid metal squeezed out and the pull-out resistance of the anchor rod is determined by the relationship between the pressure on the liquid metal sac and the volume of liquid metal squeezed out and the relationship between the pressure on the liquid metal sac and the pull-out resistance of the anchor rod.

Furthermore, the early warning device further comprises a packaging shell, wherein the packaging shell is provided with an opening matching the outer diameter of the rod;

The liquid capsule, power supply, circuit, indicator light and microfluidic channel are all arranged in the packaging shell;

The packaging shell is made of a material that has rigidity, elasticity and toughness.

Furthermore, an elastic component is also provided on the upper portion of the liquid capsule, and the liquid capsule is abutted against the inner wall of the packaging shell through the elastic component.

Furthermore, a tray is provided between the early warning device and the rock mass;

The cross-sectional area of the tray is greater than the cross-sectional area of the packaging shell.

Furthermore, the main road is also provided with an indicator light, and only when the main road indicator light is on, the force on the rod body is normal.

In order to provide a better early warning, the indicator lights of the main road and the branch roads are further displayed in different colors. Preferably, the color of the main road indicator light is not eye-catching, and can be selected as green light; as the volume of the extruded liquid metal increases, the color of the branch road indicator light becomes more eye-catching, and yellow light, orange light and red light can be selected in sequence.

The present invention also provides the above-mentioned liquid metal-based graded warning anchor bolt warning method, comprising:

Lay out the rod in the rock mass and install the early warning device and fixings;

Identify the stress condition of the pole body according to the lighting of the indicator light on the branch line of the early warning device.

The liquid metal used in the present invention is a non-toxic liquid metal, such as gallium indium tin alloy (Galinstan). Gallium indium tin alloy is a eutectic alloy composed of gallium, indium and tin. It melts at -19°C, so the alloy is in liquid state at room temperature. Gallium indium tin alloy has the characteristics of non-toxicity and low reactivity, so it has replaced toxic mercury or active sodium potassium alloy in many liquid metal applications. The liquid metal capsule in the present invention can be made of superelastic material polydimethylsiloxane (PDMS). PDMS has excellent softness, heat resistance, chemical stability, transparency, biocompatibility and easy processing, and is widely used in the field of microfluidics. The liquid metal capsule made of PDMS can deform evenly, and the deformation can be restored after the stress is removed.

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

(1) The present invention utilizes the characteristics of liquid metal, such as good fluidity, non-toxicity, stability and conductivity. Compared with using ionic liquid as a conductive medium, it is more stable, safer and more environmentally friendly;

(2) The present invention has wider applicability and can not only provide support force, but also sense the stress of the anchor rod in real time and provide early warning;

(3) The early warning of the present invention is simple and clear, and the stress condition of the rod body can be identified by the lighting condition of the indicator light of the branch.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG1 shows a schematic diagram of the liquid metal-based graded warning anchor rods of the present invention arranged in a rock mass;

FIG2 shows a front view of FIG1 ;

FIG3 shows a top view of the early warning device;

FIG4 shows a schematic diagram of the internal structure of the early warning device;

FIG5 shows a schematic diagram of the connection of the liquid capsule, power supply, circuit, indicator light and microfluidic channel of the early warning device;

Description of reference numerals:

1. Rod body; 2. Fixing part; 3. Early warning device; 31. Encapsulation shell; 32. Elastic component; 33. Liquid capsule; 331. Power supply; 332. First indicator light; 333. Second indicator light; 334. Third indicator light; 335. Fourth indicator light; 336. Microchannel; 3361. First area; 3362. Second area; 3363. Third area; 337. Wire interface; 4. Tray; 5. Rock mass.

Detailed ways

The following will be combined with the specific embodiments of the present invention and the drawings of the specification 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 making creative work are within the scope of protection of the present invention.

Example

Please refer to Figures 1 and 2. A graded warning anchor rod based on liquid metal includes a rod body 1, a fixing part 2, a warning device 3 and a tray 4. One end of the rod body 1 is anchored in a rock mass 5, and the other end of the rod body 1 is sequentially sleeved with the tray 4 and the warning device 3 and then connected to the fixing part 2. The fixing part 2 fixes the tray 4 and the warning device 3 on the rock mass 5, wherein the cross-sectional area of the tray 4 is larger than the cross-sectional area of the packaging shell 31, and the axes of the rod body 1, the tray 4, the warning device 3 and the fixing part 2 are the same.

Please refer to Figures 3 to 5. The early warning device 3 includes a packaging shell 31 with an opening matching the outer diameter of the rod body 1, and an elastic component 32, a liquid capsule 33, a power supply 331, a circuit, an indicator light and a microchannel 336 arranged in the packaging shell 31 and having an inner diameter matching the outer diameter of the rod body 1. The circuit includes a main path and a branch path. The upper part of the liquid capsule 33 is against the inner wall of the packaging shell 31 through the elastic component 32. The power supply 331 is arranged on the main path. A liquid capsule 33 is arranged on one branch path. The outlet of the liquid capsule 33 is communicated with the microchannel 336. The microchannel 336 is communicated with the branch path through a wire interface 337. As the distance of the microchannel 336 is extended, the branch path is divided into a first branch path, a second branch path and a third branch path. The main path, the first branch path, the second branch path and the third branch path are respectively provided with a first indicator light 332, a second indicator light 333, a third indicator light 334 and a fourth indicator light 335. The liquid capsule 33 is made of an elastic material and stores liquid metal gallium indium tin alloy. The microchannel 336 is divided into a first area 3361, a second area 3362 and a third area 3363 according to the relationship between the liquid metal extruded volume and the anchor rod tensile strength. When more areas of the microchannel 336 are filled with liquid metal, more branches are connected and more branch indicator lights are lit.

In this embodiment, the fixing member 2 is a nut, and one end of the rod body 1 is provided with a thread that matches the nut; the tray 4 is made of a steel plate; the material of the liquid capsule 33 is PDMS; the elastic component 32 is a spring; the microchannel 336 is made of a fiber capillary; and the material of the encapsulation shell is spring steel. In order to better provide early warning prompts, in this embodiment, the first indicator light 332 is a green light. As the distance of the microchannel 336 increases, the second indicator light 333, the third indicator light 334 and the fourth indicator light 335 of the first branch, the second branch and the third branch connected to the microchannel 336 are yellow lights, orange lights and red lights respectively.

The working principle of this embodiment is described in detail below:

According to the pressure test, the relationship between the pressure on the liquid metal capsule 33 and the volume of liquid metal squeezed out can be established; according to the anchor experiment, the relationship between the pressure on the liquid metal capsule 33 and the pull-out force of the anchor can be established. Based on these relationships, the relationship between the volume of liquid metal squeezed out and the pull-out force of the anchor can be summarized, so that the stress state of the anchor can be judged according to the volume of liquid metal squeezed out. Different anchor pull-out forces will cause different volumes of liquid metal to be squeezed out, so that liquid metal microchannels 336 of different lengths are filled with liquid metal. By arranging wire interfaces 337 at liquid metal microchannels 336 of different lengths, a graded warning anchor circuit can be connected.

The force on the rod body 1 is classified into four pressure ranges according to the tensile strength of the anchor rod:

Interval 1: The anchor force is less than or equal to 70% of the tensile strength of the anchor;

Interval 2: The anchor force is greater than 70% and less than 85% of the tensile strength of the anchor;

Interval 3: The anchor force is greater than 85% and less than 95% of the tensile strength of the anchor;

Interval 4: The force on the anchor rod is greater than 95% of the tensile strength of the anchor rod.

Meanwhile, the microchannel 336 is divided into a first region 3361 , a second region 3362 , and a third region 3363 ;

When the force on the rod 1 belongs to interval 1, the outflow of liquid metal will not make the first branch circuit conductive. At this time, only the green light of the main circuit is on.

When the force on the rod body 1 belongs to the second interval, the liquid metal fills the first area 3361 and connects the first branch. At this time, the green light and the yellow light are on;

When the force on the rod body 1 belongs to interval 3, the liquid metal fills the first area 3361 and the second area 3362, connecting the first branch and the second branch. At this time, the green light, the yellow light and the orange light are lit;

When the force on the rod body 1 belongs to interval four, the liquid metal fills the first area 3361, the second area 3362 and the third area 3363, and the first branch, the second branch and the third branch are turned on. At this time, the green light, the yellow light, the orange light and the red light are illuminated.

The gradual lighting of green, yellow, orange and red indicator lights indicates that the force on the rod 1 is gradually increasing. When the red indicator light is on, it means that the rod 1 is about to break and the dangerous behavior of the rock and soil body needs to be dealt with in time.

Therefore, the magnitude of the force on the anchor rod can be intuitively judged based on the number of branch indicator lights or the color of the lighted indicator lights. This is of course not limited to the analysis of the force on the rod body 1 in this embodiment, and other graded designs can be performed based on actual usage requirements to ensure the anchor rod's warning needs in different situations.

Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims (7)

1. A graded warning anchor rod based on liquid metal, characterized in that it comprises a rod body, a fixing part and a warning device; One end of the rod body is anchored in the rock mass, and the other end of the rod body is sleeved with the early warning device and then connected to the fixing piece, and the fixing piece fixes the early warning device on the rock mass; The early warning device comprises a liquid capsule whose inner diameter matches the outer diameter of the rod, a power source, a circuit, an indicator light and a microfluidic channel, wherein the circuit comprises a main circuit and a branch circuit, the power source is arranged on the main circuit, and the branch circuit is provided with an indicator light; The liquid capsule is made of elastic material and stores liquid metal. The outlet of the liquid capsule is connected to the microchannel. The rod body squeezes the liquid capsule under force, so that the liquid metal fills the microchannel and forms a conductive loop with the branch to make the indicator light up. As the force increases, the indicator lights of more branches light up. Wherein, the microchannel is divided into a plurality of regions according to the relationship between the extruded volume of the liquid metal and the pull-out resistance of the anchor rod; When more areas of the microchannel are filled with liquid metal, more branches are connected and more branch indicator lights light up; The relationship between the liquid metal extruded volume and the anchor rod pull-out resistance is determined by the relationship between the pressure on the liquid metal sac and the liquid metal extruded volume and the relationship between the pressure on the liquid metal sac and the anchor rod pull-out resistance. 2. The liquid metal-based graded warning anchor bolt according to claim 1, characterized in that the warning device further comprises a packaging shell, and the packaging shell is provided with an opening matching the outer diameter of the bolt; The liquid capsule, power supply, circuit, indicator light and microfluidic channel are all arranged in the packaging shell; The packaging shell is made of a material that has rigidity, elasticity and toughness. 3. The liquid metal-based graded warning anchor according to claim 2 is characterized in that an elastic component is also provided on the upper part of the liquid bag, and the liquid bag is abutted against the inner wall of the packaging shell through the elastic component. 4. The liquid metal-based graded warning anchor according to claim 2, characterized in that a tray is further provided between the warning device and the rock mass; The cross-sectional area of the tray is greater than the cross-sectional area of the packaging shell. 5. The liquid metal-based graded warning anchor rod according to any one of claims 1 to 4 is characterized in that the main road is also provided with an indicator light, and only when the main road indicator light is on, the rod body is under normal force. 6. The liquid metal-based graded warning anchor according to claim 5 is characterized in that the indicator light of the main road and the indicator light of the branch road display different colors. 7. An early warning method for a graded early warning anchor rod based on liquid metal according to claim 1, characterized in that it comprises: Lay out the rod in the rock mass and install the early warning device and fixings; Identify the stress condition of the pole body according to the lighting of the indicator light on the branch line of the early warning device.