An intelligent anchor controlled by a hydraulic servo system

Abstract

An intelligent anchor controlled by a hydraulic servo system comprises an anchor body, a loading device at one end of the anchor body, and a micro fiber grating strain sensor attached to the anchor body; the anchor body comprises a plurality of parallel steel strands; the loading device comprises an outer ring structure and an inner ring structure, the outer ring structure adopts a large through-type hydraulic jack structure, and the outer end of the piston of the outer ring structure is equipped with the inner ring structure; the inner ring structure is a disc-type structural member, and the disc-type structural member is provided with a plurality of through holes along its circumference, and an anchoring structure is fixedly installed in the through hole; the anchoring structure adopts a small through-type hydraulic jack structure, and a single-hole tool anchor is installed at the front end of the piston rod of the anchoring structure, and an anchoring hole is provided at the center of the single-hole tool anchor, and a steel strand is anchored in the anchoring hole; the hydraulic servo system drives and connects the outer ring structure and the anchoring structure. The present invention can monitor and control the internal stress of the anchor in real time, reduce the difficulty of maintenance in the operation stage of the anchor, and ensure the stability of the support structure.

Description

Technical Field

[0001] The invention relates to the field of engineering monitoring, and in particular to an intelligent anchor rod controlled by a hydraulic servo system. Background Art

[0002] As a support structure that can actively improve the strength and self-stabilizing ability of rock and soil, anchor rods are widely used in construction, water conservancy, electricity, mining tunnels, slope reinforcement and foundation pit support due to their low cost, simple construction and short construction period. With the expansion of the application field of anchor rods, engineers have found a series of problems in the process of use. For example, foundation pit projects generally use multiple anchor rods. When the excavation reaches the designed depth, additional anchor rods will be added, and then the excavation will continue downward to add the second anchor rod, and so on and so forth until the foundation pit excavation is completed. As the excavation process proceeds, the working surface of the first few anchor rods will disappear. If the support structure has a large displacement deformation in the later stage, the deformation can be quickly and effectively controlled by adjusting the force of several anchor rods around the large deformation of the support structure. However, the disappearance of the anchor rod working surface makes it difficult to adjust the force of the anchor rod. The construction unit generally adopts other methods to reinforce the support structure, which is time-consuming and labor-intensive, and cannot be controlled in the first time. If the horizontal displacement of the support structure is not controlled in time, it may induce safety accidents. In addition, there is always a problem of loss of prestress when using anchor rods. Only when the prestress of the anchor rod reaches a certain requirement can it be called active support. Once the prestress of the anchor rod does not meet the requirements, it will greatly affect the active support effect and cause safety hazards.

[0003] How to achieve real-time monitoring of the stress and loss status of anchor rods and ensure the long-term safety and stability of geotechnical anchoring projects is also the key to the development of geotechnical anchoring technology. At present, the testing methods for the stress and damage status of anchor rods at home and abroad mainly include two categories: one is based on the reflection difference detection of electromagnetic waves, sound waves, etc. in different dielectric layers; the other is through the pull-out test, using force measuring anchor rods, anchor rod pull-out meters, differential resistance strain gauges and resistance strain gauges to directly test the stress and damage status of anchor rods under the action of pull-out. However, these testing methods have the disadvantages of being easily interfered, having large test errors, poor durability and poor long-term stability, and it is difficult to meet the long-term stable monitoring needs of geotechnical anchoring projects in hidden, humid and rusty environments. Moreover, there are tens of thousands of anchor rods used in a certain project, which is a huge number, making it difficult to take all anchor rods into account in actual monitoring.

[0004] In recent years, the Internet of Things technology has been continuously applied to various fields. New technologies such as optical fiber and grating sensing technology have also developed rapidly, which has provided new ideas and new tools for engineering monitoring. In view of the shortcomings of the existing anchor bolt anchoring system, which has high detection costs and cannot meet long-term monitoring needs, the present invention combines a hydraulic servo system to propose an intelligent anchor bolt controlled by a hydraulic servo system. This anchor bolt can receive data from a micro fiber grating strain sensor in real time, and automatically process and analyze it. According to the real-time data, the anchor bolt force is controlled by the system to ensure the safety of the structure. Summary of the invention

[0005] In order to overcome the above problems, the present invention provides an intelligent anchor controlled by a hydraulic servo system.

[0006] The technical solution adopted by the present invention is: an intelligent anchor rod controlled by a hydraulic servo system, comprising an anchor rod body, a loading device located at one end of the anchor rod body, and a micro fiber grating strain sensor attached to the anchor rod body;

[0007] The anchor rod body is divided into an anchoring section and a free section. The anchor rod body includes a plurality of steel strands parallel to each other. The steel strands pass through a loading device and are fixed in an anchoring hole of the loading device. Micro fiber grating strain sensors are pasted on the outer surface of the steel strands along the axial intervals. The micro fiber grating strain sensors are used to monitor the bearing capacity of the anchor rod and the stress and strain of the steel strands. The micro fiber grating strain sensor is connected to the controller signal to transmit the detection data to the controller. The controller is connected to the hydraulic servo system signal.

[0008] The loading device includes an outer ring structure and an inner ring structure, the outer ring structure is fixed to the waist beam by bolts; the outer ring structure adopts a large through-type hydraulic jack structure, and the inner ring structure is installed on the outer end of the piston of the outer ring structure; the inner ring structure is a disc-type structural member, and a plurality of through holes are provided on the disc-type structural member along its circumference, and an anchoring structure is fixedly installed in the through hole; the anchoring structure adopts a small through-type hydraulic jack structure, and a single-hole tool anchor is installed at the front end of the piston rod of the anchoring structure, and an anchoring hole is provided at the center of the single-hole tool anchor, and a steel strand is anchored in the anchoring hole; a hydraulic servo system drives and connects the outer ring structure and the anchoring structure.

[0009] Furthermore, the arrangement density of the micro fiber Bragg grating strain sensors on the anchoring segment is greater than the arrangement density of the micro fiber Bragg grating strain sensors on the free segment.

[0010] Furthermore, the controller is electrically connected to an alarm, and when the data collected by the micro fiber grating strain sensor is lower than a preset threshold, the controller triggers the alarm to turn on.

[0011] Furthermore, the controller is connected to a remote terminal via wireless communication, and the remote terminal is a computer, a mobile phone or a tablet computer.

[0012] Furthermore, a protective cover is installed on the outside of the loading device.

[0013] Furthermore, the outer sheaths of the steel strand and the micro fiber grating sensor are provided with plastic tubes.

[0014] The beneficial effects of the present invention are:

[0015] 1) It can reduce the difficulty of anchor bolt maintenance during the operation stage and improve the anchor bolt detection efficiency during the operation stage. Compared with strain gauges, gratings have a longer life and can be used for long-term monitoring through reserved ports during the anchor bolt operation stage;

[0016] 2) The hydraulic servo system can control the anchor force in real time to keep the anchor prestress value at a fixed value. It can also adjust the anchor force according to real-time data to ensure the stability of the support structure.

[0017] 3) The anchor rods at multiple positions of the support structure can be monitored simultaneously. According to the monitoring requirements, smart anchor rods can be implanted at multiple positions to achieve overall monitoring of an area. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention.

[0019] Figure 2 It is a structural schematic diagram of the loading device.

[0020] Explanation of the reference numerals: 1-protective cover, 2-loading device, 3-steel strand, 4-micro fiber grating strain sensor, 5-hole, 6-data transmission line, 7-outer ring structure, 8-inner ring structure, 9-anchoring hole, 10-hydraulic servo system. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. 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.

[0022] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] Referring to the accompanying drawings, an intelligent anchor controlled by a hydraulic servo system includes an anchor body, a loading device located at one end of the anchor body, and a micro fiber grating strain sensor attached to the anchor body;

[0025] The anchor rod body is divided into an anchoring section and a free section. The anchor rod body includes a plurality of steel strands 3 parallel to each other. The steel strands 3 pass through the loading device 2 and are fixed in the anchoring hole of the loading device 2. Micro fiber grating strain sensors 4 are pasted on the outer surface of the steel strands 3 along the axial intervals. The micro fiber grating strain sensors 4 are used to detect the bearing capacity and stress strain of the steel strands 3. The number and density of the micro fiber grating strain sensors 4 can be adjusted according to the actual project, and can be appropriately encrypted at the anchoring section. The micro fiber grating strain sensor 4 is connected to the controller signal to transmit the detection data to the controller, and the controller is connected to the hydraulic servo system 10 signal. The steel strands 3 and the micro fiber grating sensors 4 are covered with plastic tubes. The plastic tubes can slow down the corrosion of the steel strands and ensure the survival rate of the micro fiber grating strain sensors.

[0026] The loading device 2 includes an outer ring structure 7 and an inner ring structure 8. The outer ring structure 7 is fixed to the waist beam by bolts, and a protective cover is installed on the outside of the outer ring structure 7; the outer ring structure 7 adopts a large-scale through-type hydraulic jack structure, and the inner ring structure 8 is installed on the outer end of the piston of the outer ring structure 7; the inner ring structure 8 is a disc-type structural member, and a plurality of through holes are provided on the disc-type structural member along its circumference. The number of through holes is customized according to the design, and an anchoring structure is fixedly installed in the through hole; the anchoring structure adopts a small through-type hydraulic jack structure, and a single-hole tool anchor is installed at the front end of the piston rod of the anchoring structure. An anchoring hole 9 is provided at the center of the single-hole tool anchor, and a steel strand 3 is anchored in each anchoring hole 9; the hydraulic servo system 10 drives and connects the outer ring structure and the anchoring structure.

[0027] The controller is electrically connected to the alarm. When the data collected by the micro fiber grating strain sensor is lower than a preset threshold, the controller triggers the alarm to turn on. The controller is connected to a remote terminal via wireless communication, and the remote terminal is a computer, a mobile phone or a tablet computer.

[0028] Anchor construction: Place the finished anchor into the pre-drilled hole 5, install the loading device 2 and the protective cover 1 in order from the inside to the outside, and ensure that each steel strand 3 passes through an anchor hole 9. Before grouting, the micro fiber grating strain sensor 4, the data transmission line 6, and the hydraulic servo system should be tested to see if they are working properly. After the grouting is completed, the anchor tensioning work can be carried out. When applying prestress, considering that the loading device involved in the present invention has a small range, a conventional hydraulic jack can be used to tension it to the design value first, and then the loading device 2 can be used to lock the steel strand 3.

[0029] Anchor operation: The monitoring data of the support structure is fed back to the controller through the fiber Bragg grating strain sensor 4 and other monitoring equipment. The controller performs a preliminary analysis according to the pre-set settings. If a certain monitoring data exceeds the threshold, the controller will automatically warn and report the danger. In addition, the operator can make real-time adjustments to the stress of the anchor through the loading device 2 according to the actual situation. For example, when tensioning the anchor, a single steel strand 3 may be unevenly stressed. If the stress of a single steel strand 3 is too large or too small, it will affect the overall stress of the anchor. At this time, the controller can send a command to the hydraulic servo system 10, and use the anchoring structure to hydraulically adjust the stress of a single steel strand 3. For example, if the prestress of the anchor is lost too much, it is necessary to adjust the prestress of the entire anchor, and the outer ring structure of the loading device is used to hydraulically adjust the entire anchor. In addition, the controller can control multiple anchors in an area at the same time, and adjust the anchors of the entire area at the same time, so as to achieve overall control of the support structure.

[0030] The contents described in the embodiments of this specification are merely an enumeration of the implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. An intelligent anchor controlled by a hydraulic servo system, characterized in that: It includes an anchor rod body, a loading device located at one end of the anchor rod body, and a micro fiber grating strain sensor attached to the anchor rod body; The anchor rod body is divided into an anchoring section and a free section. The anchor rod body includes a plurality of steel strands parallel to each other. The steel strands pass through a loading device and are fixed in an anchoring hole of the loading device. Micro fiber grating strain sensors are pasted on the outer surface of the steel strands along the axial intervals. The micro fiber grating strain sensors are used to monitor the bearing capacity of the anchor rod and the stress and strain of the steel strands. The micro fiber grating strain sensors are connected to the controller signal to transmit the detection data to the controller. The controller is connected to the hydraulic servo system signal. The loading device comprises an outer ring structure and an inner ring structure, wherein the outer ring structure is fixed to the waist beam by bolts; the outer ring structure adopts a large through-type hydraulic jack structure, and the inner ring structure is installed on the outer end of the piston of the outer ring structure; the inner ring structure is a disc-type structural member, and a plurality of through holes are arranged on the disc-type structural member along its circumference, and an anchoring structure is fixedly installed in the through hole; the anchoring structure adopts a small through-type hydraulic jack structure, and a single-hole tool anchor is installed at the front end of the piston rod of the anchoring structure, and an anchoring hole is arranged at the center of the single-hole tool anchor, and a steel strand is anchored in the anchoring hole; the hydraulic servo system drives and connects the outer ring structure and the anchoring structure; The arrangement density of the micro fiber Bragg grating strain sensors on the anchoring section is greater than the arrangement density of the micro fiber Bragg grating strain sensors on the free section; The controller is electrically connected to the alarm, and when the data collected by the micro fiber grating strain sensor is lower than a preset threshold, the controller triggers the alarm to turn on; The controller is connected to a remote terminal via wireless communication, and the remote terminal is a computer, a mobile phone or a tablet computer; The outer sheaths of the steel strand and the micro fiber grating sensor are provided with plastic tubes.

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