Active intelligent anchor rod for geotechnical engineering and control system

Abstract

The invention provides a geotechnical engineering active intelligent anchor rod which comprises an anchor rod body, a metal shell, a steel strand and an anchor head, the steel strand is used for applying and adjusting the prestress of the anchor rod, and the anchor rod body is divided into an anchoring section and a free section. The geotechnical engineering active intelligent anchor rod comprises a piezoelectric module, an electric heating transpiration module and an annular miniature air blower, the piezoelectric module is connected to one end of an anchor rod body, and a piezoelectric module body is composed of a plurality of piezoelectric ring pieces which are machined into an annular stacked shape through piezoelectric materials and is in rigid connection with a steel strand; the electric heating transpiration module is arranged on the periphery of the anchoring section of the anchor rod and comprises a sleeve, a heat conduction layer and a heat insulation film. The annular micro air blower comprises a micro air blower and a lantern ring connected with the micro air blower, the micro air blower communicates with the flow guide cavity, and under the action of the micro air blower, water vapor is discharged from the anchoring section to the anchor head through the flow guide cavity; and a hole for allowing the steel strand to pass through is reserved in the lantern ring. The invention also discloses a geotechnical engineering active control system.

Description

Technical Field

[0001] The present invention belongs to the field of intelligent geotechnical and underground engineering, and specifically relates to an active intelligent anchor rod design for geotechnical engineering and active control for digital twin technology, which can realize active control of most disasters such as large-scale earthquakes and landslides, and can also realize dynamic monitoring and active control of parameters in the process of engineering blasting, mechanical rock breaking, and water conservancy project construction. Background Art

[0002] The existing technologies are often passive in the protection of geotechnical or underground related projects under the vibration environment caused by earthquakes, blasting or mechanical rock breaking construction, and long-term environmental adaptability is a crucial issue. These projects may include super-large tunnels, military facilities, large slopes, etc., and the complexity of the underground environment and potential safety hazards must be considered during their design and construction, such as sudden vibrations caused by natural earthquakes or man-made earthquakes such as large earthquakes, engineering blasting, rock bursts, traditional mechanical rock breaking, military nuclear explosions, etc.

[0003] At present, the application of sensor technology in geotechnical engineering is mostly used for monitoring deformation of tunnel surrounding rock or intelligent monitoring of temperature field. [1] , or by arranging corresponding sensors inside the support anchor to achieve real-time monitoring [2-3] However, the above technology can only obtain the real-time monitoring of the relevant parameters and changes of underground engineering. When facing sudden large-scale earthquakes, explosions, and even nuclear explosions, it can only play the role of parameter acquisition. The above disasters cannot actively control and intervene in the deformation and damage of geotechnical engineering structures, and thus cannot reduce or avoid the destructive effects of disasters on geotechnical engineering structures. In addition, the use of prestressed shock-absorbing anchor rods as shock-absorbing and energy-absorbing devices in tunnels [4] Only anchor rods can be used to achieve a certain degree of shock absorption and energy dissipation, but the degree of adjustment is very limited, and there is a lack of monitoring and evaluation process for the structure, making it difficult to provide real-time parameters for geotechnical structures, and it is impossible to control the scale and range of adjustment, and thus it cannot play a good role in disaster prevention and buffering for geotechnical structures. The above-mentioned monitoring and control methods are all passive control methods that lack intelligent systems, which often cannot meet the protection requirements for sudden underground projects under special circumstances. In addition, this passive protection may be restricted in some cases, so it is impossible to effectively provide timely and effective protection for important geotechnical projects and related facilities. At present, combined with existing technologies, among the many requirements for the protection of geotechnical engineering structures and facilities, in addition to being able to achieve real-time monitoring of the structure, whether the structure itself can be used for active control intervention will become the key to reducing or avoiding large-scale damage and instability in geotechnical structures.

[0004] Related Literature

[0005] [1] Zhao Xueliang, Wan Chunfeng, Xia Cheng. Tunnel surrounding rock monitoring method based on multifunctional intelligent anchor, application number: CN201610563323.

[0006] [2] Xue Yiguo, Liu Qiushi, Li Zhiqiang, et al. An intelligent monitoring device and method for geological disasters in anchor-bolt tunnel engineering. Application number: CN202210582779.7.

[0007] [3] Li Qinghai, Yuan Shuhao, Li Shengjiang, et al. A regional intelligent induction anchor for mining, application number: CN202311746603.1.

[0008] [4] Guo Han, He Chao, Zhou Shunhua, et al. A new tunnel shock absorption and energy dissipation system using prestressed special shock-absorbing anchor rods [P]. Shanghai: CN202311111392.4, 2023-10-20.

[0009] [5] Zheng Guan, Yu Wang, Fusion of three-dimensional geotechnical and geophysical data for developing digital twin of underground space, Soils and Foundations, Volume 64, Issue 6, 2024.

[0010] [6]Haofeng Gong, Dong Su, Shiqi Zeng, Xiangsheng Chen, Advancements in digital twin modeling for underground spaces and lightweight geometric modeling technologies, Automation in Construction, Volume 165, 2024.

[0011] [7] Tao Li, Xiaojun Li, Yi Rui, Jiaxin Ling, Sicheng Zhao, Hehua Zhu, Digital twin for intelligent tunnel construction, Automation in Construction, Volume 158, 2024. Summary of the invention

[0012] In order to overcome the potential damage of conventional anchor rods to geotechnical engineering structures caused by vibrations due to large earthquakes, engineering blasting, mechanical rock breaking, etc., and the instability disasters of geotechnical engineering caused by water conservancy project construction, precipitation, snowmelt, etc., this invention proposes an intelligent anchor rod for engineering earthquake resistance and maintaining the stability of geotechnical engineering and an active control system coordinated with it. The technical solution is as follows:

[0013] An active intelligent anchor rod for geotechnical engineering includes an anchor rod body, a metal shell, a steel strand and an anchor head for applying and adjusting the prestress of the anchor rod, and the anchor rod body is divided into an anchoring section and a free section. The active intelligent anchor rod for geotechnical engineering includes a piezoelectric module, an electrothermal evaporation module and an annular micro blower, wherein:

[0014] The piezoelectric module is connected to one end of the anchor body. The piezoelectric module body is composed of a plurality of piezoelectric rings processed into a ring-shaped stack with piezoelectric materials, which are rigidly connected to the steel strand. When the piezoelectric module is deformed upon receiving an electric pulse wave, the steel strand is tensilely deformed. The number of piezoelectric materials and piezoelectric rings should ensure that the cooperative deformation of the piezoelectric material and the steel strand generated by the stacking meets the prestressing regulation requirements.

[0015] The electric heating transpiration module is arranged at the periphery of the anchoring section of the anchor rod, and includes a sleeve, a heat-conducting layer and a heat-insulating film from the outside to the inside. An annular flow-guiding cavity is formed between the heat-insulating film and the heat-conducting layer, and a plurality of electric heating tubes are arranged in the flow-guiding cavity; the heat-insulating film is used to isolate the interference of the electric heating tube heating process on the steel strand inside the anchoring section of the anchor rod; the heat-conducting layer is located on the outer surface of the electric heating tube to ensure that the electric heating tube is not in direct contact with water and plays a heat-conducting role, so that the heat of the electric heating tube is transferred in the flow-guiding cavity, so as to play an electric heating transpiration role on the water introduced into the anchor rod flow-guiding cavity; the sleeve is provided with micro water-conducting holes;

[0016] The micro-blower comprises a micro-blower and a sleeve connected thereto. The micro-blower is connected to the guide cavity. During the heating process of the electric heating tube, water around the anchor rod enters the guide cavity through the micro-water guide hole. After the water in the guide cavity evaporates into water vapor, the water vapor is discharged through the guide cavity along the anchoring section toward the anchor head under the action of the micro-blower. The sleeve is provided with a hole for accommodating the steel strand to pass through.

[0017] Furthermore, the sleeve is made of a thermally responsive porous material, and the thermally responsive porous material expands when the electric heating tube is started to form micro water-conducting holes.

[0018] Furthermore, the collar is made of insulating material, which can fix the spatial position of the steel strand on the one hand, and prevent the micro-blower from causing deformation of the steel strand on the other hand.

[0019] The present invention also provides a geotechnical engineering active control system implemented by adopting the geotechnical engineering active intelligent anchor rod, comprising an electrical resistance tomography module and a data processing and feedback terminal;

[0020] The electrical resistance tomography module uses the metal shell of each geotechnical active intelligent anchor as an electrode. The signal collected by the electrical resistance tomography module is sent to the data processing and feedback terminal for inversion imaging to obtain the conductivity distribution and change in the geotechnical structural section area where the anchor system is located, so as to monitor the change of soil moisture content in the geotechnical active intelligent anchor arrangement area; when it is monitored that the soil moisture content in a geotechnical active intelligent anchor arrangement area exceeds the threshold, the electrothermal transpiration module is activated to energize the electric heating pipe and generate heat, and the water in the anchoring area is introduced into the diversion cavity through the micro water-conducting holes distributed on the surface of the casing. After being heated by the electric heating pipe in the electrothermal transpiration module, the water is evaporated into water vapor, and an air flow is generated by a micro blower connected to the diversion cavity, and discharged through the diversion cavity along the anchoring section toward the anchor head until the moisture content drops below the active control threshold, and the electrothermal transpiration module is closed, thereby realizing active control of the moisture content of the anchoring section of the anchor.

[0021] Furthermore, the geotechnical engineering active control system further includes sensors for collecting environmental parameters, and the sensors for collecting environmental parameters include optical fiber sensors, stress, strain, and temperature sensors. The optical fiber sensors are arranged outside the geotechnical engineering structure to monitor vibration signals, and the stress, strain sensors, and temperature sensors are arranged at preset structural control points inside the geotechnical engineering structure to obtain stress, strain, and temperature parameters of the geotechnical engineering structure control points. The signals collected by each sensor are sent to a data processing and feedback terminal;

[0022] The data processing and feedback terminal obtains the multimodal parameters of the physical entity space according to the signals collected by the various sensors, constitutes a comprehensive data set from the multimodal parameters of the physical entity space, and performs virtual numerical simulation space parameter feature mapping, combines the comprehensive data set obtained by historical monitoring data and the damage and stability analysis of the geotechnical engineering physical model, constructs an active control model for evaluating geotechnical engineering structures, and realizes active control of geotechnical engineering active intelligent anchors.

[0023] Furthermore, the method of constructing an active control model for evaluating geotechnical engineering structures and realizing instantaneous active control of geotechnical engineering active intelligent anchors includes:

[0024] The real-time data collected by the sensors used to collect environmental parameters are evaluated, and the peak vibration velocity PPV and surrounding rock damage depth D of the control point calculated in real time are used to calculate the peak vibration velocity PPV and surrounding rock damage depth D of the control point. pl To calculate the damage factor of geotechnical structures The evaluation indexes of peak vibration velocity are as follows: And surrounding rock damage zone depth evaluation index: PPV in the formula max and are the vibration peak velocity threshold and the damage depth threshold of the surrounding rock damage zone, respectively, and the damage factor Defined by:

[0025]

[0026] In the formula, α1, α2, ..., α n , β1, β2, ..., β n To reflect the influence coefficient of vibration peak velocity and surrounding rock damage zone depth, it is determined through parameter calibration and data fitting;

[0027] set up is the threshold of the damage factor, and the active control start parameter D ec satisfy:

[0028] When the active control starts parameter D ec =1, the calculation of piezoelectric active control parameters is started;

[0029] The piezoelectric active control parameters include the frequency of the instantaneous pulse voltage required to cause the piezoelectric module to deform due to the inverse piezoelectric effect. amplitude Duration

[0030] Determine the equivalent pulse voltage and express it as

[0031] Assume the piezoelectric strain tensor of the piezoelectric module Piezoelectric stress tensor Piezoelectric constant matrix d and stiffness matrix of piezoelectric material The strain tensor of the piezoelectric module satisfies the following formula:

[0032]

[0033] In the formula, K is the conversion coefficient between the required deformation electric field intensity and voltage of the piezoelectric material;

[0034] The objective function of piezoelectric active control is as follows:

[0035]

[0036] In the formula, σ tgt is the total prestress applied by the piezoelectric anchor to the rock and soil, is the deformation required for the initial stretching of the piezoelectric anchor to the target prestress, E is the stiffness matrix of the built-in steel strand of the piezoelectric anchor, κ1 is the correction coefficient of the total prestress of the piezoelectric anchor, and λ is the deformation weakening coefficient of the damage factor calculated at the control point of the geotechnical engineering structure that has an adverse effect on the prestress of the piezoelectric anchor.

[0037] Furthermore, the BP neural network architecture is used to calculate the active control parameters to realize the active control of the active intelligent anchor in geotechnical engineering. The method is as follows:

[0038] In the calculation process of damage factor, the peak vibration velocity PPV of the control point and the surrounding rock damage depth D pl As an input function, the damage factor As output parameters, the first BP neural network is constructed;

[0039] In the process of calculating the deformation of piezoelectric materials, the deformation of piezoelectric materials is As the input parameter of the neural network, the equivalent pulse voltage pre-applied on the piezoelectric material is As the output parameter, the second BP neural network is formed; in the objective function calculation process of piezoelectric active control, the damage factor As the input parameter of the neural network, the total prestress σ applied by the piezoelectric anchor to the rock and soil tgt As output parameters, a third BP neural network is formed; the second and third BP neural networks are trained in a front-to-back parallel manner, and the output parameters of the second BP neural network are used as known parameters of the objective function of the third BP neural network for calculation;

[0040] When the above three BP neural networks have complete training sets, the peak vibration velocity PPV and surrounding rock damage depth D pl , under the action of the above-mentioned failure parameters, the equivalent pulse voltage required by the piezoelectric module of the active intelligent anchor in geotechnical engineering can be obtained by instantaneous feedback and the total prestress σ applied by the piezoelectric anchor to the rock and soil in real time tgt , apply an equivalent pulse voltage of corresponding magnitude to the piezoelectric module of the active intelligent anchor in geotechnical engineering The total prestress σ applied by the piezoelectric anchor to the rock and soil is calculated in real time tgt , realizing the active control of geotechnical engineering active intelligent anchor rods in the anchoring area of ​​geotechnical engineering structures.

[0041] In order to solve the problem of poor active control ability of geotechnical engineering structures in most geotechnical engineering projects under vibration load conditions such as large earthquakes and blasting, the present invention proposes an active intelligent anchor rod for geotechnical engineering and a corresponding active control method for disaster prevention, which are mainly aimed at two application scenarios: vibrations caused by super-large earthquakes, blasting, and mechanical rock breaking in geotechnical engineering structures, and large-scale landslides caused by excessive water content in the soil due to the construction of water conservancy projects, precipitation, snowmelt, etc. The anchor rod comprises a piezoelectric module and an electrothermal transpiration module, wherein the piezoelectric module utilizes the inverse piezoelectric effect of piezoelectric materials, and can apply a high-voltage pulse wave to the piezoelectric module on the anchor rod to cause the piezoelectric module to produce an inverse piezoelectric effect, and utilize the piezoelectric module to drive the anchoring deformation section of the anchor rod to deform, thereby realizing active adjustment of the prestress of the anchor rod; wherein the electrothermal transpiration module introduces moisture in the soil into the anchor rod when the moisture content of the soil is too high, and discharges it from the anchor rod through electrothermal transpiration and airflow devices, thereby ensuring that the moisture content of the soil in the anchoring area is within a safe and stable range; in addition, in order to provide active control parameters for active intelligent anchor rods in geotechnical engineering, optical fiber sensors are arranged on the periphery of the geotechnical engineering structure to collect vibration signals generated by earthquakes, blasting, etc.; the present invention also combines electrical resistance tomography Like technology, by taking the entire anchor rod as an electrode, the anchor rod system in a geotechnical engineering section constitutes corresponding excitation electrodes and measurement electrodes in a preset order, and the conductivity field of the area where the anchor rod system of the geotechnical engineering section is located is obtained through adjacent excitations, so as to obtain the conductivity field mutation signal caused by the sudden increase in water content inside the geotechnical engineering due to conditions such as water conservancy project construction, rainfall, and snowmelt; in addition, a variety of sensors are arranged inside the geotechnical engineering structure to collect environmental parameter data such as stress and strain of the geotechnical engineering structure; the vibration signals and environmental parameters collected above are input into the digital-physical fusion twin model, and the multimodal parameters collected by the above-mentioned various sensors are input and the numerical model is updated in real time to form a digital-physical fusion twin model in which the numerical model and the physical entity model interact in real time. Through real-time calculation of the twin model of digital-physical fusion, the damage parameters of the geotechnical structure are obtained. For example, by calculating the damage parameters such as the vibration peak velocity and the depth of the surrounding rock damage zone of the relevant control measurement points arranged in the geotechnical anchoring area, the damage state of the geotechnical structure is quantified, and an active control evaluation model is established. The damage factor is calculated by quantifying the damage parameters of the model, and the damage threshold is set according to the damage factor. If the damage factor of the twin model of digital-physical fusion is lower than the damage threshold, the active warning information and active control information will be automatically triggered. The corresponding active control parameters are predicted by the BP neural network, and the corresponding active control signals are transmitted to the active intelligent anchor rod of the geotechnical engineering. After receiving the corresponding signals, the active intelligent anchor rod of the geotechnical engineering performs active control of the piezoelectric module or the electric thermal evaporation module to realize the instantaneous adjustment of the prestress in the anchoring area and the control and adjustment of the soil moisture content in the anchoring area. At the same time, the processing system will transmit the above information to the monitoring center of the geotechnical structure or the terminal equipment of the management personnel for judgment and reference.The above-mentioned active control provides a means for comprehensive monitoring and active control of geotechnical engineering sites, and reduces or offsets the adverse effects of external vibration or excessive water content on the destruction and instability of geotechnical engineering structures by adjusting the mechanical properties and water content of the rock mass in the anchoring area.

[0042] The present invention uses active intelligent anchor rods in geotechnical engineering as active control equipment. On the one hand, it combines with electrical resistance tomography technology to realize dynamic monitoring of conductivity in the anchoring area, and adjusts the water content in the anchoring area through active intelligent anchor rods in geotechnical engineering, so as to provide active control means for geotechnical engineering structures facing stability damage caused by water conservancy project construction, precipitation, snowmelt, and potential water inrush; on the other hand, it uses multimodal monitoring data from various sensors as the source of parameter iteration and feature mapping of digital-physical fusion twins, combined with the prediction advantages of BP neural networks, it can provide real-time active control for geotechnical engineering structures facing potential destructive disasters that may exist in the process of large-scale earthquakes, engineering blasting, and mechanical rock breaking; the present invention can be used to ensure the structural integrity and stability of geotechnical engineering structures facing most disaster conditions, and is expected to provide effective active protection measures for the construction and operation of super-large tunnels, large slopes, and national defense projects and facilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the structure of an active intelligent anchor in geotechnical engineering according to an embodiment of the present invention;

[0044] Figure 2 It is the digital-physical fusion twin and the active intelligent anchor active control mechanism of geotechnical engineering in the embodiment of the present invention;

[0045] Figure 3 This is a full flow chart of active control of piezoelectric modules for active intelligent anchors in geotechnical engineering according to an embodiment of the present invention;

[0046] Figure 4 This is a full flow chart of active control of the geotechnical engineering active intelligent anchor electrothermal transpiration module according to the embodiment of the present invention

[0047] Figure 5 This is a BP neural network structure diagram of an embodiment of the present invention;

[0048] The accompanying drawings are as follows:

[0049] 1. Piezoelectric module; 2. Steel strand; 3. Metal housing; 4. Ring-shaped micro-blower; 4-1. Micro-blower; 4-2. Sleeve ring; 5. Flow guide cavity; 6. Electric heating pipe; 7. Thermal insulation film; 8. Thermal conductive layer; 9. Anchor head; 10. Sleeve made of thermally responsive porous material DETAILED DESCRIPTION

[0050] The following is a complete and clear description of the relevant technical solutions of the present invention 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.

[0051] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside" and the like appear in the description, the orientation or position relationship indicated is based on the orientation or position relationship shown in the corresponding drawings. It is only for the convenience of describing the present invention and simplifying the description. It is not intended to indicate or imply that the referred component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood and used as a limitation of the present invention.

[0052] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and the like in the description should be understood in a broad sense, for example, it can be a rigid connection, a detachable connection, a mechanical connection, an electrical connection, etc.; it can be a direct connection, an indirect connection through an intermediate medium, or the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0053] In order to solve the problem of poor active control ability of geotechnical engineering structures in most geotechnical engineering projects under vibration load conditions such as large earthquakes and blasting, the present invention proposes an active intelligent anchor rod for geotechnical engineering and a corresponding active control method for disaster prevention, which are mainly aimed at two application scenarios: vibrations caused by super-large earthquakes, blasting, and mechanical rock breaking in geotechnical engineering structures, and large-scale landslides caused by excessive water content in the soil due to the construction of water conservancy projects, precipitation, snowmelt, etc. The anchor rod comprises a piezoelectric module and an electrothermal transpiration module, wherein the piezoelectric module utilizes the inverse piezoelectric effect of piezoelectric materials, and can apply a high-voltage pulse wave to the piezoelectric module on the anchor rod to cause the piezoelectric module to produce an inverse piezoelectric effect, and utilize the piezoelectric module to drive the anchoring deformation section of the anchor rod to deform, thereby realizing active adjustment of the prestress of the anchor rod; wherein the electrothermal transpiration module introduces moisture in the soil into the anchor rod when the moisture content of the soil is too high, and discharges it from the anchor rod through electrothermal transpiration and airflow devices, thereby ensuring that the moisture content of the soil in the anchoring area is within a safe and stable range; in addition, in order to provide active control parameters for active intelligent anchor rods in geotechnical engineering, optical fiber sensors are arranged on the periphery of the geotechnical engineering structure to collect vibration signals generated by earthquakes, blasting, etc.; the present invention also combines electrical resistance tomography Like technology, by taking the entire anchor rod as an electrode, the anchor rod system in a geotechnical engineering section constitutes corresponding excitation electrodes and measurement electrodes in a preset order, and the conductivity field of the area where the anchor rod system of the geotechnical engineering section is located is obtained through adjacent excitations, so as to obtain the conductivity field mutation signal caused by the sudden increase in water content inside the geotechnical engineering due to conditions such as water conservancy project construction, rainfall, and snowmelt; in addition, a variety of sensors are arranged inside the geotechnical engineering structure to collect environmental parameter data such as stress and strain of the geotechnical engineering structure; the vibration signals and environmental parameters collected above are input into the digital-physical fusion twin model, and the multimodal parameters collected by the above-mentioned various sensors are input and the numerical model is updated in real time to form a digital-physical fusion twin model in which the numerical model and the physical entity model interact in real time. Through real-time calculation of the twin model of digital-physical fusion, the damage parameters of the geotechnical structure are obtained. For example, by calculating the damage parameters such as the vibration peak velocity and the depth of the surrounding rock damage zone of the relevant control measurement points arranged in the geotechnical anchoring area, the damage state of the geotechnical structure is quantified, and an active control evaluation model is established. The damage factor is calculated by quantifying the damage parameters of the model, and the damage threshold is set according to the damage factor. If the damage factor of the twin model of digital-physical fusion is lower than the damage threshold, the active warning information and active control information will be automatically triggered. The corresponding active control parameters are predicted by the BP neural network, and the corresponding active control signals are transmitted to the active intelligent anchor rod of the geotechnical engineering. After receiving the corresponding signals, the active intelligent anchor rod of the geotechnical engineering performs active control of the piezoelectric module or the electric thermal evaporation module to realize the instantaneous adjustment of the prestress in the anchoring area and the control and adjustment of the soil moisture content in the anchoring area. At the same time, the processing system will transmit the above information to the monitoring center of the geotechnical structure or the terminal equipment of the management personnel for judgment and reference.The above-mentioned active control provides a means for comprehensive monitoring and active control of geotechnical engineering sites, and reduces or offsets the adverse effects of external vibration or excessive water content on the destruction and instability of geotechnical engineering structures by adjusting the mechanical properties and water content of the rock mass in the anchoring area.

[0054] Referring to the accompanying drawings, the active intelligent anchor rod of geotechnical engineering of the present invention includes an anchor rod body, a piezoelectric module 1 located at one end of the anchor rod body close to the pad, and an electrothermal transpiration module embedded in the anchor rod body; an active control method for geotechnical engineering includes the above-mentioned active intelligent anchor rod of geotechnical engineering, optical fiber sensors for collecting environmental parameters, various sensors such as stress and strain sensors, a resistance tomography module for monitoring the changes in soil moisture content in the arrangement area of ​​the active intelligent anchor rod of geotechnical engineering, and a data processing and feedback terminal.

[0055] The anchor rod body is divided into two parts: an anchoring section and a free section. The anchor rod body includes a plurality of parallel steel strands 2 for applying prestress, which are used to apply and adjust the prestress of the active intelligent anchor rod for geotechnical engineering. The steel strands 2 pass through the pad of the anchor rod body and are rigidly connected to the piezoelectric module 1 to ensure that the steel strands 2 and the piezoelectric module 1 produce the same collaborative deformation, and the other end passes through the entire anchor rod and maintains a rigid connection with the anchor head 9.

[0056] The piezoelectric module 1 is located at one end of the anchor body close to the pad, and the main body of the piezoelectric module 1 is composed of a plurality of piezoelectric ring sheets processed into an annular stack with piezoelectric materials. The piezoelectric material here should be a material with a relatively high piezoelectric constant, including but not limited to piezoelectric quartz, lead zirconium titanium (PZT) piezoelectric ceramics, polymer-based composite piezoelectric materials, etc. The selected piezoelectric material and the number of piezoelectric sheets should ensure that the piezoelectric material can generate a coordinated deformation with the steel strand through stacking to meet the prestressing adjustment requirements of the corresponding geotechnical engineering. At the same time, it should be noted that when the piezoelectric module 1 receives an electric pulse wave and deforms, the deformation generated by all the piezoelectric sheets contained in the piezoelectric module 1 starts from one end of the pad and sequentially generates tension deformation on the steel strand 2.

[0057] The electrothermal evaporation module is located in the anchoring section of the anchor rod, and includes a plurality of electrothermal tubes 6 parallel to each other and parallel to the anchoring section of the anchor rod body, a heat insulation film 7, a heat conductive layer 8, a flow guide cavity 5, and an annular micro-blower 4 arranged on the upper part of the flow guide cavity 5. The electrothermal tube 6 is located in the flow guide cavity 5, and a certain number of electrothermal tubes 6 can be accommodated in the flow guide cavity 5, and the electrothermal evaporation requirements during the operation of the anchor rod can be met; the heat insulation film 7 is coated on the inner surface of the flow guide cavity 5 in contact with the electrothermal tube, so as to isolate the interference of the electrothermal tube 5 heating process on the steel strand 2 inside the anchoring section of the anchor rod; the heat conductive layer 8 is located on the outer surface of the electrothermal tube 6, and has a certain thickness to ensure that the electrothermal tube 6 does not directly contact with water, and at the same time has good thermal conductivity, and can fully transfer the heat of the electrothermal tube 6 to the flow guide cavity 5, so as to play an electrothermal evaporation role on the water introduced into the anchor rod guide cavity 5. The diversion cavity 5 is an annular cavity formed by a metal sleeve nested in the anchoring section of the anchor body to the anchor head 9 segment. The sleeve is made of a thermally responsive porous material. When the thermally responsive porous material is started, the thermally responsive porous material expands due to heat, and the water guide hole opens. When the moisture content in the soil is abnormal, the geotechnical active intelligent anchor activates the electric heating transpiration module, so that the electric heating tube 6 is energized and generates heat, and the water in the anchoring area is introduced into the diversion cavity 5 through the micro-holes distributed on the surface of the sleeve 10 made of thermally responsive porous material through capillary action. After being heated by the electric heating tube 6 in the electric heating transpiration module, the water is evaporated into water vapor, and then an annular micro-blower 4 at the top of the diversion cavity 5 generates airflow, which is discharged along the anchoring section toward the anchor head 9 through the diversion cavity 5, thereby realizing active control of the moisture content of the anchoring section of the anchor.

[0058] The annular micro-blower 4 mainly includes two parts. One is the micro-blower 4-1. When the electric heating tube 6 in the electric evaporation module heats the water body and evaporates it into water vapor, the micro-blower 4-1 discharges the water vapor through the guide cavity 5 along the anchoring section toward the anchor head 9. The other is the ring 4-2 with reserved holes for steel strands to pass through, and the holes can accommodate a corresponding number of steel strands 2; the ring 4-2 is made of insulating material. In addition to further fixing the spatial position of the steel strands 2, it can also avoid the possible influence of the micro-blower 4-1 on the deformation of the steel strands 2.

[0059] Sensors used to collect environmental parameters include optical fiber sensors, stress and strain sensors. Optical fiber sensors are arranged outside the geotechnical structure perpendicular to the geotechnical structure profile and maintain a good data communication connection with the data processing terminal to monitor vibration signals caused by earthquakes, engineering blasting, mechanical rock breaking, etc. The above vibration signals mainly refer to the vibration frequency f and vibration phase obtained by the optical fiber sensor collection and processing. Amplitude A; the latter is a variety of stress, strain, temperature and other types of sensors arranged at the preset structural control points inside the geotechnical engineering structure to obtain the stress σ of the geotechnical engineering structure control point k , strain ε k , Temperature T k And other environmental parameters, each sensor maintains a good data communication connection with the data processing terminal.

[0060] The resistance tomography module of the present invention refers to a high-power resistance tomography unit that can support tunnel profile imaging. Resistance tomography technology is a detection technology that uses the distribution or change of conductivity inside the test body or test area as the imaging basis, which can realize long-term real-time monitoring of the test body or test area, and obtain the moisture content of the test area according to the distribution or change of conductivity. In the present invention, the detection range of the resistance tomography module is the anchoring area where the active intelligent anchor system of geotechnical engineering is distributed. One end of the resistance tomography module is well connected to the metal shell 3 coated on the outside of the active intelligent anchor of geotechnical engineering through an external clamp, and the other end is connected to the data processing and feedback terminal. It is worth noting that the metal shell 3 of the active intelligent anchor of geotechnical engineering is made of a metal material with good conductivity, which can ensure that the resistance tomography uses the active intelligent anchor of geotechnical engineering as an excitation electrode or a measurement electrode for monitoring. There are many ways to collect electrode excitation and measurement signals of the resistance tomography module in the prior art. The present invention adopts a quasi-adjacent excitation mode, and the test method is as follows:

[0061] Taking the tunnel section involved in this embodiment as an example, 16 geotechnical active intelligent anchors are arranged around the tunnel section, which are numbered Z1, Z2, Z3, ..., Z 16 The excitation and measurement sequence of a rotation projection is as follows:

[0062] Table 1 Excitation and measurement sequence of one rotation projection

[0063]

[0064]

[0065] The electrode numbers for the 2nd, 3rd, and 4th columns satisfy the following relationship:

[0066]

[0067] Where n is the electrode number, i is the excitation sequence, from 1 to 16 is a measurement cycle. If the number of electrodes is 16, then a measurement cycle requires 16 rotation projections, k is the additional number of the sequence in the table, Z n is the corresponding electrode sequence.

[0068] The amount of data collected in the above cycle is N = 16 × 13 = 208 in total. Then, after the above data is cleaned and denoised, the Tikhonov regularization method is used for inversion imaging, so that the conductivity distribution and changes in the geotechnical engineering structure profile area where the anchor system is located can be obtained in real time, and then the water content distribution and changes in the area can be obtained. When imaging detects that the moisture content in the anchoring area has a gradient increase, an early warning will be sent to the technicians at the data processing and feedback terminal, and the electric thermal transpiration module will be turned on according to the preset parameters. When the electric thermal transpiration module is turned on, the data processing and feedback terminal will synchronously turn on the diversion cavity 5 of the active intelligent anchor of geotechnical engineering. At this time, the moisture outside the anchor can be sucked into the diversion cavity 5 of the anchor through capillary action, and then heated by the electric heating tubes 6 distributed in the electric thermal transpiration module to evaporate the water body into water vapor. The annular micro-blower 4 at the top of the diversion cavity 5 generates an airflow, which is discharged through the diversion cavity 5 along the anchoring section toward the anchor head 9 until the moisture content drops below the active control threshold. The electric thermal transpiration module is turned off, and the active decision-making and regulation behavior of the technicians at the data processing and feedback terminal are combined to jointly constitute and realize the active control of the moisture content in the anchoring area of ​​the active intelligent anchor of geotechnical engineering.

[0069] The data processing and feedback terminal is a digital-physical fusion twin simulation platform for real-time parameter iteration and feature mapping. The data processing and feedback terminal is connected to the aforementioned optical fiber sensor, stress sensor, strain sensor, temperature sensor and other sensors, as well as the electrical resistance tomography module; the digital-physical fusion twin is a high-fidelity digital model that is created in a virtual numerical simulation space by combining existing numerical simulation methods, and is established in the numerical simulation space to correspond to the geotechnical engineering physical object and maintain real-time feature mapping and interaction. [5-7] The digital-physical fusion twin feature mapping platform can receive the multimodal parameters of the physical entity space collected by the above-mentioned sensors in real time. The multimodal parameters of the physical entity space will constitute a comprehensive data set, and perform virtual numerical simulation space parameter feature mapping. Combined with the comprehensive data set obtained by historical monitoring and the damage and stability analysis of the geotechnical engineering physical model, an active control model for evaluating geotechnical engineering structures is constructed. The active control model is as follows:

[0070] Taking the tunnel chamber as an example, the active control model will evaluate the real-time data collected by the sensor and calculate the peak vibration velocity PPV and surrounding rock damage depth D of the control point based on the real-time calculation. pl To calculate the damage factor of geotechnical structures The evaluation indexes of peak vibration velocity are as follows: And surrounding rock damage zone depth evaluation index: PPV in the formula max and They are the vibration peak velocity threshold and the damage depth threshold of the surrounding rock damage zone, which need to be determined by combining historical monitoring data with physical tests or numerical simulation results. It should be defined by:

[0071]

[0072] In the formula, α1, α2, ..., α n , β1, β2, ..., β n In order to reflect the influence coefficients of vibration peak velocity and surrounding rock damage zone depth, each influence coefficient needs to be combined with historical monitoring data and physical test or numerical simulation results for parameter calibration and data fitting. At the same time, the threshold of the damage factor should be determined by combining historical monitoring data with physical test or numerical simulation results. Active control start parameter D ec satisfy: When the active control starts parameter D ec =1, the calculation of the piezoelectric active control parameters will be started, wherein the piezoelectric active control parameters include the frequency of the instantaneous pulse voltage required to cause the piezoelectric module 1 to produce the inverse piezoelectric effect and deform. amplitude Duration It is worth noting that the instantaneous pulse voltage is applied in the form of a pulse square wave; the equivalent pulse voltage is calculated by combining the amplitude, frequency and other parameters of the instantaneous pulse voltage. For an ideal square wave signal, half of the time in one cycle is the amplitude voltage, so the equivalent pulse voltage at this time can be expressed as In addition, it also includes the parameters involved in the constitutive equation of piezoelectric materials, such as the piezoelectric strain tensor Piezoelectric stress tensor Piezoelectric constant matrix d and stiffness matrix of piezoelectric material For an ideal square wave, the strain tensor of the piezoelectric material can be calculated by combining the constitutive equation of the piezoelectric material, which satisfies the following formula:

[0073]

[0074] Where K is the conversion coefficient between the required deformation electric field strength and voltage of the piezoelectric material, and its value is related to the structure and geometric dimensions of the piezoelectric material.

[0075] Based on the parameters of the piezoelectric module 1, the objective function of the piezoelectric active control is given as follows:

[0076]

[0077] In the formula, σ tgt is the total prestress applied by the piezoelectric anchor to the rock and soil, is the deformation required for the initial stretching of the piezoelectric anchor to the target prestress, E is the stiffness matrix of the built-in steel strand of the piezoelectric anchor, κ1 is the correction coefficient of the total prestress of the piezoelectric anchor, and its value needs to be determined based on physical tests or numerical simulations. λ is the deformation weakening coefficient of the damage factor calculated at the control point of the geotechnical engineering structure that has an adverse effect on the prestress of the piezoelectric anchor, and its value needs to be determined based on physical tests or numerical simulations.

[0078] Furthermore, in order to speed up the active control, the sensor network composed of multiple sensors such as optical fiber sensors and stress sensors and the digital-physical fusion twin feature mapping platform, which maps the parameters of the numerical model in real time, realizes the "super real-time" active control of the geotechnical active intelligent anchor rod, and the BP neural network architecture is introduced to achieve efficient data processing. Please note that the "super real-time" here means that before the vibration waves caused by large earthquakes, explosions, etc. are transmitted to the structure, due to the completeness of the neural network training samples, the required active control parameters can be quickly obtained and output according to the input parameters, and the geotechnical active intelligent anchor rod can be instantaneously actively controlled. When the aforementioned vibration waves are transmitted to the structure, the anchor rod has already completed the active control in advance, adjusted the prestress of the anchor rod, and optimized the mechanical properties of the anchoring area, so as to avoid the vibration waves from causing damage and destruction to the geotechnical structure. It is an advance prediction behavior.

[0079] The present invention embeds a digital-physical fusion twin feature mapping platform into the BP neural network architecture to optimize the parameters of the multiple functions mentioned above. The input parameters and output parameters of each function are described as follows:

[0080] In the calculation process of damage factor, the peak vibration velocity PPV of the control point and the surrounding rock damage depth D pl As an input function, the damage factor As output parameters, the results obtained through historical and real-time calculations of the digital-physical fusion twin feature mapping platform constitute the training set of the neural network.

[0081] In the process of calculating the deformation of piezoelectric materials, the deformation of piezoelectric materials is As the input parameter of the neural network, the equivalent pulse voltage pre-applied on the piezoelectric material is is the output parameter; in the objective function calculation process of piezoelectric active control, the damage factor As the input parameter of the neural network, the total prestress σ applied by the piezoelectric anchor to the rock and soil tgtAs output parameters, please note that the two neural networks described here for calculating the piezoelectric material deformation and the piezoelectric active control objective function are trained in a front-to-back parallel manner. The output parameters of the former neural network will be calculated as the known parameters of the objective function of the latter neural network. It should be noted that the input and output parameters involved in the two neural networks described here must be set by the initial values ​​according to the geotechnical engineering structure morphology and the experience of technical personnel, and then the data results obtained by historical and real-time calculations monitored by the digital-physical fusion twin feature mapping platform are continuously adjusted and optimized until the piezoelectric material deformation can meet the structural safety requirements. At this time, the optimized input parameters and output parameters can be used as the training sets of these two neural networks.

[0082] It is worth noting that the activation function in the BP neural network mentioned above uses the ReLU function, the loss function uses the MSE function, and the optimization algorithm uses the Adam algorithm, which can effectively capture and optimize the mathematical relationship between the input parameters and the output parameters.

[0083] When the above neural network has a complete training set, the peak vibration velocity PPV of the control point and the surrounding rock damage depth D can be obtained through the digital-physical fusion twin feature mapping platform. pl , under the action of the above-mentioned failure parameters, the equivalent pulse voltage required by the piezoelectric module of the active intelligent anchor in geotechnical engineering can be obtained by instantaneous feedback and the total prestress σ applied by the piezoelectric anchor to the rock and soil in real time tgt , so that the equivalent pulse voltage of corresponding magnitude can be applied to the piezoelectric module 1 of the active intelligent anchor of geotechnical engineering The total prestress σ applied by the piezoelectric anchor to the rock and soil is calculated in real time tgt , thereby realizing the active control of the geotechnical engineering active intelligent anchor rod in the anchoring area of ​​the geotechnical engineering structure and improving the seismic resistance of the geotechnical engineering structure.

[0084] It is worth noting that the contents described in the embodiments of the 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 active intelligent anchor for geotechnical engineering, comprising an anchor body, a metal shell, a steel strand and an anchor head for applying and adjusting the prestress of the anchor, wherein the anchor body is divided into an anchoring section and a free section, and is characterized in that: The geotechnical engineering active intelligent anchor comprises a piezoelectric module, an electrothermal evaporation module and an annular micro blower, wherein: The piezoelectric module is connected to one end of the anchor body. The piezoelectric module body is composed of a plurality of piezoelectric rings processed into a ring-shaped stack with piezoelectric materials, which are rigidly connected to the steel strand. When the piezoelectric module is deformed upon receiving an electric pulse wave, the steel strand is tensilely deformed. The number of piezoelectric materials and piezoelectric rings should ensure that the cooperative deformation of the piezoelectric material and the steel strand generated by the stacking meets the prestressing regulation requirements. The electric heating transpiration module is arranged at the periphery of the anchoring section of the anchor rod, and includes a sleeve, a heat-conducting layer and a heat-insulating film from the outside to the inside. An annular flow-guiding cavity is formed between the heat-insulating film and the heat-conducting layer, and a plurality of electric heating tubes are arranged in the flow-guiding cavity; the heat-insulating film is used to isolate the interference of the electric heating tube heating process on the steel strand inside the anchoring section of the anchor rod; the heat-conducting layer is located on the outer surface of the electric heating tube to ensure that the electric heating tube is not in direct contact with water and plays a heat-conducting role, so that the heat of the electric heating tube is transferred in the flow-guiding cavity, so as to play an electric heating transpiration role on the water introduced into the anchor rod flow-guiding cavity; the sleeve is provided with micro water-conducting holes; The annular micro-blower comprises a micro-blower and a sleeve ring connected thereto. The micro-blower is connected to the guide cavity. During the heating process of the electric heating tube, water around the anchor rod enters the guide cavity through the micro-water guide hole. After the water in the guide cavity evaporates into water vapor, the water vapor is discharged through the guide cavity along the anchoring section toward the anchor head under the action of the micro-blower. The sleeve ring is provided with a hole for accommodating the steel strand to pass through.

2. The geotechnical engineering active intelligent anchor according to claim 1, characterized in that: The sleeve is made of a thermally responsive porous material, and the thermally responsive porous material expands when the electric heating tube is started to form micro water-conducting holes.

3. The geotechnical engineering active intelligent anchor according to claim 1, characterized in that: The sleeve ring is made of insulating material, which can fix the spatial position of the steel strand on the one hand, and prevent the micro-blower from causing deformation of the steel strand on the other hand.

4. A geotechnical engineering active control system implemented by the geotechnical engineering active intelligent anchor according to any one of claims 1 to 3, comprising an electrical resistance tomography module and a data processing and feedback terminal; The electrical resistance tomography module uses the metal shell of each geotechnical active intelligent anchor as an electrode. The signal collected by the electrical resistance tomography module is sent to the data processing and feedback terminal for inversion imaging to obtain the conductivity distribution and change in the geotechnical structural section area where the anchor system is located, so as to monitor the change of soil moisture content in the geotechnical active intelligent anchor arrangement area; when it is monitored that the soil moisture content in a geotechnical active intelligent anchor arrangement area exceeds the threshold, the electrothermal transpiration module is activated to energize the electric heating pipe and generate heat, and the water in the anchoring area is introduced into the diversion cavity through the micro water-conducting holes distributed on the surface of the casing. After being heated by the electric heating pipe in the electrothermal transpiration module, the water is evaporated into water vapor, and an air flow is generated by a micro blower connected to the diversion cavity, and discharged through the diversion cavity along the anchoring section toward the anchor head until the moisture content drops below the active control threshold, and the electrothermal transpiration module is closed, thereby realizing active control of the moisture content of the anchoring section of the anchor.

5. The geotechnical engineering active control system according to claim 4, characterized in that: The geotechnical engineering active control system further includes sensors for collecting environmental parameters, and the sensors for collecting environmental parameters include optical fiber sensors, stress, strain, and temperature sensors. The optical fiber sensors are arranged outside the geotechnical engineering structure to monitor vibration signals, and the stress, strain sensors, and temperature sensors are arranged at preset structural control points inside the geotechnical engineering structure to obtain stress, strain, and temperature parameters of the geotechnical engineering structure control points. The signals collected by each sensor are sent to a data processing and feedback terminal; The data processing and feedback terminal obtains the multimodal parameters of the physical entity space according to the signals collected by the various sensors, constitutes a comprehensive data set from the multimodal parameters of the physical entity space, and performs virtual numerical simulation space parameter feature mapping, combines the comprehensive data set obtained by historical monitoring data and the damage and stability analysis of the geotechnical engineering physical model, constructs an active control model for evaluating geotechnical engineering structures, and realizes active control of geotechnical engineering active intelligent anchors.

6. The geotechnical engineering active control system according to claim 5, characterized in that: The method of constructing an active control model for evaluating geotechnical engineering structures and realizing instantaneous active control of geotechnical engineering active intelligent anchors includes: The real-time data collected by the sensors used to collect environmental parameters are evaluated, and the peak vibration velocity PPV and surrounding rock damage depth D of the control point calculated in real time are used to calculate the peak vibration velocity PPV and surrounding rock damage depth D of the control point. pl To calculate the damage factor of geotechnical structures The evaluation indexes of peak vibration velocity are as follows: And surrounding rock damage zone depth evaluation index: PPV in the formula max and are the vibration peak velocity threshold and the damage depth threshold of the surrounding rock damage zone, respectively, and the damage factor Defined by: In the formula, α1, α2, ..., α n , β1, β2, ..., β n To reflect the influence coefficient of vibration peak velocity and surrounding rock damage zone depth, it is determined through parameter calibration and data fitting; set up is the threshold of the damage factor, and the active control start parameter D ec satisfy: When the active control starts parameter D ec =1, the calculation of piezoelectric active control parameters is started; The piezoelectric active control parameters include the frequency of the instantaneous pulse voltage required to cause the piezoelectric module to deform due to the inverse piezoelectric effect. amplitude Duration Determine the equivalent pulse voltage and express it as Assume the piezoelectric strain tensor of the piezoelectric module Piezoelectric stress tensor Piezoelectric constant matrix d and stiffness matrix of piezoelectric material The strain tensor of the piezoelectric module satisfies the following formula: In the formula, K is the conversion coefficient between the required deformation electric field intensity and voltage of the piezoelectric material; The objective function of piezoelectric active control is as follows: In the formula, σ tgt is the total prestress applied by the piezoelectric anchor to the rock and soil, is the deformation required for the initial stretching of the piezoelectric anchor to the target prestress, E is the stiffness matrix of the built-in steel strand of the piezoelectric anchor, κ1 is the correction coefficient of the total prestress of the piezoelectric anchor, and λ is the deformation weakening coefficient of the damage factor calculated at the control point of the geotechnical engineering structure that has an adverse effect on the prestress of the piezoelectric anchor.

7. The geotechnical engineering active control system according to claim 6, characterized in that: The BP neural network architecture is used to calculate the active control parameters to realize the active control of active intelligent anchor bolts in geotechnical engineering. The method is as follows: In the calculation process of damage factor, the peak vibration velocity PPV of the control point and the surrounding rock damage depth D pl As an input function, the damage factor As output parameters, the first BP neural network is constructed; In the process of calculating the deformation of piezoelectric materials, the deformation of piezoelectric materials is As the input parameter of the neural network, the equivalent pulse voltage pre-applied on the piezoelectric material is As the output parameter, the second BP neural network is formed; in the objective function calculation process of piezoelectric active control, the damage factor As the input parameter of the neural network, the total prestress σ applied by the piezoelectric anchor to the rock and soil tgt As output parameters, the third BP neural network is constructed; The second and third BP neural networks are trained in a front-to-back parallel manner, and the output parameters of the second BP neural network will be used as known parameters of the objective function of the third BP neural network for calculation; When the above three BP neural networks have complete training sets, the peak vibration velocity PPV and surrounding rock damage depth D pl , under the action of the above-mentioned failure parameters, the equivalent pulse voltage required by the piezoelectric module of the active intelligent anchor in geotechnical engineering can be obtained by instantaneous feedback and the total prestress σ applied by the piezoelectric anchor to the rock and soil in real time tgt , apply an equivalent pulse voltage of corresponding magnitude to the piezoelectric module of the active intelligent anchor in geotechnical engineering The total prestress σ applied by the piezoelectric anchor to the rock and soil is calculated in real time tgt , realizing the active control of geotechnical engineering active intelligent anchor rods in the anchoring area of ​​geotechnical engineering structures.

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