An active intelligent anchor and control system for geotechnical engineering

Abstract

The present invention provides an active intelligent anchor for geotechnical engineering, comprising an anchor body, a metal shell, a steel strand for applying and adjusting anchor prestress, and an anchor head. The anchor body is divided into an anchoring section and a free section. The active intelligent anchor for geotechnical engineering comprises a piezoelectric module, an electrothermal evaporation module, and an annular micro-blower. The piezoelectric module is connected to one end of the anchor body. The piezoelectric module body is composed of a plurality of piezoelectric rings made of piezoelectric material and stacked in an annular shape, which are rigidly connected to the steel strand. The electrothermal evaporation module is arranged on the periphery of the anchoring section of the anchor, and comprises a sleeve, a heat-conducting layer, and a heat-insulating film. The annular micro-blower comprises a micro-blower and a collar connected thereto. The micro-blower is connected to a guide cavity. Under the action of the micro-blower, water vapor is discharged through the guide cavity along the anchoring section toward the anchor head. The collar is provided with a hole for accommodating the steel strand. The present invention also provides an active control system for geotechnical engineering.

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. It 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 during engineering blasting, mechanical rock breaking, and water conservancy project construction. Background Art

[0002] Current technologies for protecting geotechnical and underground projects in the context of vibrations caused by earthquakes, blasting, or mechanical rock breaking are often passive, making long-term environmental adaptability a crucial issue. These projects may include ultra-large tunnels, military facilities, and large slopes. Their design and construction must consider the complexity of the underground environment and potential safety hazards, such as sudden vibrations caused by natural or man-made earthquakes, such as large earthquakes, engineering blasting, rockbursts, traditional mechanical rock breaking, and military nuclear explosions.

[0003] At present, the application of sensing technology in geotechnical engineering is mostly used in tunnel surrounding rock deformation monitoring or temperature field intelligent monitoring. [1] , or by arranging corresponding sensors inside the support anchor to achieve real-time monitoring [2-3] However, the above technology can only obtain real-time monitoring of 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 ] Anchor rods can only be used to achieve a certain degree of shock absorption and energy consumption adjustment, 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 engineering structures, and the scale and range of adjustment cannot be controlled, and thus cannot play a good disaster prevention and buffering role for geotechnical engineering structures. The above-mentioned monitoring and control methods are all passive control methods that lack an intelligent system, which often cannot meet the protection requirements for sudden underground projects under special circumstances. In addition, this passive protection may be limited in some cases, so it is impossible to effectively provide timely and effective protection for important geotechnical engineering and related facilities. At present, based on the existing technology, 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 of geotechnical engineering 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 hazards 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] To overcome the potential damage to geotechnical structures caused by vibrations from large earthquakes, blasting, and mechanical rock breaking, as well as the potential instability hazards associated with water conservancy construction, precipitation, and snowmelt, this invention proposes an intelligent anchor for earthquake resistance and geotechnical stability maintenance, along with an associated active control system. The technical solution is as follows:

[0013] An active intelligent anchor rod for geotechnical engineering, comprising an anchor rod body, a metal shell, a steel strand for applying and adjusting anchor rod prestress, and an anchor head. The anchor rod body is divided into an anchoring section and a free section. The active intelligent anchor rod for geotechnical engineering comprises 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 main body of the piezoelectric module is composed of a plurality of piezoelectric rings processed into an annular stack of piezoelectric materials, which are rigidly connected to the steel strand. When the piezoelectric module deforms upon receiving an electric pulse wave, it generates tension deformation on the steel strand. 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 stack meets the prestressing adjustment requirements.

[0015] The electric evaporation module is arranged on 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 guide 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 guide cavity; the heat-insulating film is used to isolate the electric heating tube from interfering with the steel strand inside the anchoring section of the anchor rod during the heating process; the heat-conducting layer is located on the outer surface of the electric heating tube to ensure that the electric heating tube does not come into direct contact with water and plays a heat-conducting role, so that the heat of the electric heating tube is transferred in the flow guide cavity, so as to play an electric evaporation role on the water introduced into the anchor rod guide cavity; the sleeve is provided with micro water-conducting holes;

[0016] The micro-blower includes a micro-blower and a collar 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, under the action of the micro-blower, the water vapor is discharged through the guide cavity along the anchoring section toward the anchor head; the collar is reserved with a hole for accommodating the steel strand to pass through.

[0017] Furthermore, the sleeve is made of a thermally responsive porous material, which forms micro water-conducting holes after being heated and expanded when the electric heating tube is started.

[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, comprising an electrical resistance tomography module and a data processing and feedback terminal;

[0020] The electrical resistance tomography module uses the metal casing of each geotechnical active intelligent anchor as an electrode. The signals collected by the electrical resistance tomography module are sent to a data processing and feedback terminal for inversion imaging. This module obtains the distribution and changes of electrical conductivity within the geotechnical structural cross-section where the anchor system is located, thereby monitoring the changes in soil moisture content within the geotechnical active intelligent anchor arrangement area. When the soil moisture content within a geotechnical active intelligent anchor arrangement area is detected to exceed a threshold, the electrothermal transpiration module is activated, energizing and heating the electric heating pipe. Water in the anchoring area is introduced into the diversion cavity through micro-water guide holes distributed on the surface of the casing. After being heated by the electric heating pipe in the electrothermal transpiration module, the water evaporates into water vapor, which is then discharged through the diversion cavity along the anchoring section toward the anchor head by generating airflow through a micro-blower connected to the diversion cavity. The airflow is discharged through the diversion cavity along the anchoring section toward the anchor head until the water content drops below the active control threshold. The electrothermal transpiration module is then deactivated, thereby achieving 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, 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 based on the signals collected by the various sensors, constructs a comprehensive data set from the multimodal parameters of the physical entity space, and performs virtual numerical simulation space parameter feature mapping. By combining the comprehensive data set obtained from historical monitoring data and the damage and stability analysis of the geotechnical engineering physical model, an active control model for evaluating geotechnical engineering structures is constructed, and active control of geotechnical engineering active intelligent anchor rods is realized.

[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 indicators of peak vibration velocity are: 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, and the damage factor It is defined by the following formula:

[0025]

[0026] Where α1, α2, ..., α n , β1, β2, ..., β n In order 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 starting 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 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] Where 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] Where 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 that adversely affects the prestress of the piezoelectric anchor due to the damage factor calculated at the control point of the geotechnical engineering structure.

[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 calculated. As the input parameter of the neural network, the equivalent pulse voltage pre-applied to the piezoelectric material is used. 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 are used as known parameters of the objective function of the third BP neural network for calculation;

[0040] When the three BP neural networks mentioned above 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 the equivalent pulse voltage of corresponding magnitude to the piezoelectric module of the active intelligent anchor in geotechnical engineering And calculate the total prestress σ applied by the piezoelectric anchor to the rock and soil 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 when facing 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 disaster prevention control method. It is mainly aimed at two application scenarios: geotechnical engineering structures are subjected to vibrations caused by super-large earthquakes, blasting, and mechanical rock breaking; 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 includes a piezoelectric module and an electrothermal evaporation module, wherein the piezoelectric module utilizes the inverse piezoelectric effect of the piezoelectric material, 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 anchor deformation section of the anchor rod to deform, thereby realizing active adjustment of the prestress of the anchor rod; wherein the electrothermal evaporation 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 the electrothermal evaporation and airflow device, 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 the active intelligent anchor rod of 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 computation of a digital-physical fusion twin model, failure parameters of geotechnical structures are obtained. For example, by calculating failure parameters such as the peak vibration velocity and the depth of the surrounding rock damage zone at relevant control points in the geotechnical anchorage zone, the damage state of the geotechnical structure is quantified. This is then used to establish an active control assessment model. The damage factor is calculated by quantifying the model's damage parameters, and a damage threshold is set based on the damage factor. If the damage factor of the digital-physical fusion twin model falls below the damage threshold, active warning and active control signals are automatically triggered. The corresponding active control parameters are predicted using a BP neural network and transmitted to the geotechnical active intelligent anchor. Upon receiving the corresponding signal, the geotechnical active intelligent anchor performs active control of the piezoelectric module or the electrothermal evaporation module to achieve instantaneous adjustment of the prestress in the anchorage zone and control of the soil moisture content in the anchorage zone. The processing system also transmits this information to the geotechnical structure monitoring center or the management personnel's terminal device for reference and assessment.The above-mentioned active control provides a means for comprehensive monitoring and active control of geotechnical engineering sites. By adjusting the mechanical properties and moisture content of the rock mass in the anchoring area, the adverse effects of external vibration or excessive moisture content on the damage and instability of geotechnical engineering structures can be mitigated or offset.

[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 electrical conductivity in the anchoring area, and adjusts the moisture content in the anchoring area through active intelligent anchor rods in geotechnical engineering, providing 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 during 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 under 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 active intelligent anchor structure in geotechnical engineering according to an embodiment of the present invention;

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

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

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

[0047] Figure 5 This is a structural diagram of a BP neural network according to 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 embodiments described 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 making creative efforts 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, and 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 on the present invention.

[0052] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "mounted" and "connected" should be understood in a broad sense. For example, they can refer to a rigid connection, a detachable connection, a mechanical connection, an electrical connection, etc.; they can be directly connected, indirectly connected through an intermediate medium, or internally connected between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0053] In order to solve the problem of poor active control ability of geotechnical engineering structures in most geotechnical engineering projects when facing 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 disaster prevention control method. It is mainly aimed at two application scenarios: geotechnical engineering structures are subjected to vibrations caused by super-large earthquakes, blasting, and mechanical rock breaking; 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 includes a piezoelectric module and an electrothermal evaporation module, wherein the piezoelectric module utilizes the inverse piezoelectric effect of the piezoelectric material, 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 anchor deformation section of the anchor rod to deform, thereby realizing active adjustment of the prestress of the anchor rod; wherein the electrothermal evaporation 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 the electrothermal evaporation and airflow device, 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 the active intelligent anchor rod of 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 computation of a digital-physical fusion twin model, failure parameters of geotechnical structures are obtained. For example, by calculating failure parameters such as the peak vibration velocity and the depth of the surrounding rock damage zone at relevant control points in the geotechnical anchorage zone, the damage state of the geotechnical structure is quantified. This is then used to establish an active control assessment model. The damage factor is calculated by quantifying the model's damage parameters, and a damage threshold is set based on the damage factor. If the damage factor of the digital-physical fusion twin model falls below the damage threshold, active warning and active control signals are automatically triggered. The corresponding active control parameters are predicted using a BP neural network and transmitted to the geotechnical active intelligent anchor. Upon receiving the corresponding signal, the geotechnical active intelligent anchor performs active control of the piezoelectric module or the electrothermal evaporation module to achieve instantaneous adjustment of the prestress in the anchorage zone and control of the soil moisture content in the anchorage zone. The processing system also transmits this information to the geotechnical structure monitoring center or the management personnel's terminal device for reference and assessment.The above-mentioned active control provides a means for comprehensive monitoring and active control of geotechnical engineering sites. By adjusting the mechanical properties and moisture content of the rock mass in the anchoring area, the adverse effects of external vibration or excessive moisture content on the damage and instability of geotechnical engineering structures can be mitigated or offset.

[0054] Referring to the accompanying drawings, the active intelligent anchor rod for 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 nested on the anchor rod body; a geotechnical engineering active control method includes the above-mentioned active intelligent anchor rod for geotechnical engineering, various sensors such as optical fiber sensors, stress and strain sensors for collecting environmental parameters, an electrical resistance tomography module for monitoring changes in soil moisture content in the area where the active intelligent anchor rod for geotechnical engineering is arranged, and a data processing and feedback terminal.

[0055] The anchor rod body is divided into two parts: the anchoring section and the free section. The anchor rod body includes multiple parallel steel strands 2 that apply prestress, which are used to apply and adjust the prestress of the active intelligent anchor rod in geotechnical engineering. The steel strand 2 passes through the pad of the anchor rod body and is rigidly connected to the piezoelectric module 1 to ensure that the steel strand 2 and the piezoelectric module 1 produce collaborative deformation with the same deformation amount. 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. 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. It should be ensured that the selected piezoelectric material and the number of piezoelectric sheets can ensure that the piezoelectric material generates a cooperative deformation with the steel strand through stacking to meet the prestress 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 multiple electric heating tubes 6, which are parallel to each other and the anchoring section of the anchor rod body, a thermal insulation film 7, a thermal conductive layer 8, a flow guide cavity 5, and an annular micro-blower 4 disposed above the flow guide cavity 5. The electric heating tubes 6 are located within the flow guide cavity 5, which can accommodate a certain number of electric heating tubes 6 and meet the electric heating evaporation requirements during the operation of the anchor rod. The thermal insulation film 7 covers the inner surface of the flow guide cavity 5 that contacts the electric heating tubes to isolate the heating process of the electric heating tubes 5 from interfering with the steel strands 2 within the anchoring section of the anchor rod. The thermal conductive layer 8 is located on the outer surface of the electric heating tubes 6 and has a certain thickness to ensure that the electric heating tubes 6 do not come into direct contact with water. At the same time, it provides good thermal conductivity, allowing the heat from the electric heating tubes 6 to be fully transferred to the flow guide cavity 5, thereby causing electrothermal evaporation of water introduced into the anchor rod's flow guide cavity 5. The diversion cavity 5 is an annular cavity formed by a metal sleeve nested outside the anchor body from the anchoring section to the anchor head 9. The sleeve is made of a thermally responsive porous material. When the electric heating tube is activated, the thermally responsive porous material expands due to heat, and the water guide holes open. When the moisture content in the soil is abnormal, the geotechnical active intelligent anchor activates the electric heating transpiration module, energizing the electric heating tube 6 and generating heat. The tiny holes (referred to as water guide holes in this patent) opened by the thermal expansion of the sleeve 10 made of the thermally responsive porous material are used to guide the water in the anchoring area into the diversion cavity 5 through the micro-water guide holes distributed on the surface of the sleeve 10 made of the thermally responsive porous material through capillary action. After being heated by the electric heating tube 6 in the electric heating transpiration module, the water evaporates into water vapor. The water is then discharged through the annular micro-blower 4 at the top of the diversion cavity 5 along the anchoring section toward the anchor head 9 to achieve 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 fiber optic sensors, stress and strain sensors. Fiber optic sensors are placed outside the geotechnical structure perpendicular to the geotechnical structure section 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 fiber optic sensor. 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, and 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 electrical conductivity inside the test body or test area as the imaging basis. It can realize long-term real-time monitoring of the test body or test area, and obtain the moisture content of the test area based on the distribution or change of electrical 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 covering 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 for one 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 total amount of data collected in the above cycle is N = 16 × 13 = 208. After the above data is cleaned and denoised, the Tikhonov regularization method is used for inversion imaging. This allows the real-time acquisition of the conductivity distribution and changes in the geotechnical engineering structure profile area where the anchor system is located, and thus the moisture content distribution and changes in the area. When imaging detects a gradient increase in the moisture content in the anchoring area, an early warning will be sent to the technicians at the data processing and feedback terminal, and the electric thermal evaporation module will be automatically turned on according to preset parameters. When the electric thermal evaporation module is turned on, the data processing and feedback terminal will simultaneously turn on the diversion cavity 5 of the geotechnical active intelligent anchor. At this time, moisture outside the anchor can be sucked into the diversion cavity 5 of the anchor by capillary action, and then heated by the electric heating tubes 6 distributed in the electric thermal evaporation module to evaporate the water into water vapor. The annular micro-blower 4 at the top of the diversion cavity 5 generates an air flow, 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 evaporation module is then turned off. Combined with the active decision-making and control behavior of the technicians at the data processing and feedback terminal, active control of the moisture content in the anchoring area of ​​the geotechnical active intelligent anchor is jointly constituted and realized.

[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 created in a virtual numerical simulation space by combining existing numerical simulation methods, corresponding to the geotechnical engineering physical object in the numerical simulation space and maintaining 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 form a comprehensive data set and perform virtual numerical simulation space parameter feature mapping. Combined with the comprehensive data set obtained from 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 indicators of peak vibration velocity are: 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. The damage factor It should be defined by the following formula:

[0071]

[0072] Where 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 value of the damage factor should be determined by combining historical monitoring data with physical test or numerical simulation results. Active control startup 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] Where 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 strands 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, to accelerate active control, a digital-physical fusion twin feature mapping platform, which integrates a sensor network composed of multiple sensors such as fiber optic sensors and stress sensors with real-time mapping and calculation of numerical model parameters, was used to implement "super real-time" active control of geotechnical active intelligent anchors. By introducing a BP neural network architecture, efficient data processing was achieved. Please note that "super real-time" here means that before the vibration waves caused by large earthquakes, explosions, etc. reach the structure, the required active control parameters can be quickly obtained and output based on the input parameters due to the completeness of the neural network training samples. Instantaneous active control of the geotechnical active intelligent anchor is then performed. When the aforementioned vibration waves reach the structure, the anchor has already completed active control in advance, adjusted the anchor prestress, and optimized the mechanical properties of the anchoring zone. This is a proactive prediction behavior that can prevent damage and destruction to the geotechnical structure caused by the vibration waves.

[0079] The present invention embeds a data-physics 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 calculated. As the input parameter of the neural network, the equivalent pulse voltage pre-applied to the piezoelectric material is used. 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 themselves based on the geotechnical engineering structure morphology and the experience of technical personnel. 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 input parameters and 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 in geotechnical engineering And calculate the total prestress σ applied by the piezoelectric anchor to the rock and soil 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 scope of protection of the present invention should not be regarded as limited to the specific forms described in the embodiments. The scope of protection of the present invention also extends to equivalent technical means that can be thought of 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 casing, a steel strand for applying and adjusting anchor prestress, and an anchor head. The anchor body is wrapped with the metal casing, and the steel strand is arranged inside the anchor body. The anchor body is divided into an anchoring section and a free section. The invention is characterized in that: The geotechnical engineering active intelligent anchor includes 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 material, which is rigidly connected to one end of the steel strand. The other end of the steel strand is connected to the anchor head. When the piezoelectric module is deformed by receiving an electric pulse wave, it generates tension deformation on the steel strand. 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 stack meets the prestressing adjustment requirements. The electric evaporation module is arranged on 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 guide 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 guide cavity; the heat-insulating film is used to isolate the electric heating tube from interfering with the steel strand inside the anchoring section of the anchor rod during the heating process; the heat-conducting layer is located on the outer surface of the electric heating tube to ensure that the electric heating tube does not come into direct contact with water and plays a heat-conducting role, so that the heat of the electric heating tube is transferred in the flow guide cavity, so as to play an electric evaporation role on the water introduced into the anchor rod guide cavity; the sleeve is provided with micro water-conducting holes; The annular micro-blower includes a micro-blower and a collar 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, under the action of the micro-blower, the water vapor is discharged through the guide cavity along the anchoring section toward the anchor head; the collar is reserved 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, which expands when heated when the electric heating tube is started, forming micro water-conducting holes.

3. The geotechnical engineering active intelligent anchor according to claim 1, characterized in that: The sleeve 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 using 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 casing of each geotechnical active intelligent anchor as an electrode. The signals collected by the electrical resistance tomography module are sent to a data processing and feedback terminal for inversion imaging. This module obtains the distribution and changes of electrical conductivity within the geotechnical structural cross-section where the anchor system is located, thereby monitoring the changes in soil moisture content within the geotechnical active intelligent anchor arrangement area. When the soil moisture content within a geotechnical active intelligent anchor arrangement area is detected to exceed a threshold, the electrothermal transpiration module is activated, energizing and heating the electric heating pipe. Water in the anchoring area is introduced into the diversion cavity through micro-water guide holes distributed on the surface of the casing. After being heated by the electric heating pipe in the electrothermal transpiration module, the water evaporates into water vapor, which is then discharged through the diversion cavity along the anchoring section toward the anchor head by generating airflow through a micro-blower connected to the diversion cavity. The airflow is discharged through the diversion cavity along the anchoring section toward the anchor head until the water content drops below the active control threshold. The electrothermal transpiration module is then deactivated, thereby achieving 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, wherein 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, 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 based on the signals collected by the various sensors, constructs a comprehensive data set from the multimodal parameters of the physical entity space, and performs virtual numerical simulation space parameter feature mapping. By combining the comprehensive data set obtained from historical monitoring data and the damage and stability analysis of the geotechnical engineering physical model, an active control model for evaluating geotechnical engineering structures is constructed, and active control of geotechnical engineering active intelligent anchor rods is realized.

6. The geotechnical engineering active control system according to claim 5, characterized in that: The method for constructing an active control model for evaluating geotechnical structures and realizing instantaneous active control of geotechnical 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 indicators of peak vibration velocity are: 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, and the damage factor It is defined by the following formula: Where α1, α2, ..., α n , β1, β2, ..., β n In order 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 starting 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 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: Where 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: Where 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 that adversely affects the prestress of the piezoelectric anchor due to the damage factor calculated at the control point of the geotechnical engineering structure.

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 strain tensor of the piezoelectric material is used. As the input parameter of the neural network, the equivalent pulse voltage pre-applied to the piezoelectric material is used. 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 the known parameters of the objective function of the third BP neural network for calculation; When the three BP neural networks mentioned above have complete training sets, the peak vibration velocity PPV and surrounding rock damage depth D of the control points are obtained. 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 the equivalent pulse voltage of corresponding magnitude to the piezoelectric module of the active intelligent anchor in geotechnical engineering And calculate the total prestress σ applied by the piezoelectric anchor to the rock and soil 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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