Evaluation method of surrounding rock characteristics of engineering tunnel during service period

Abstract

The present invention relates to the technical field of physical model test data analysis, and in particular to a method for evaluating tunnel surrounding rock characteristics during the service period of an engineering tunnel. Static and dynamic experiments are performed through a tunnel surrounding rock physical model to monitor the load and deformation changes of anchor rods, gantry supports and support cylinders to evaluate the homogeneity and stability of the tunnel surrounding rock. The present invention is used to truly reproduce the force process and support characteristics of the engineering tunnel during service in the laboratory, effectively analyze the acquired data, and establish a connection between the support system response and the tunnel deformation state during the tunnel service period. Dynamic and static load parameters are applied through a tunnel surrounding rock physical model consistent with the engineering site, and data is acquired for analysis, which can better restore the engineering practice process, ensure the consistency of the model process with the engineering scene, thereby improving the authenticity and reliability of the simulation results, better guiding the design of coal mine tunnel support schemes, and can also reversely infer the deformation and failure morphology of the tunnel according to the response characteristics of support components such as anchor rods.

Description

Technical Field

[0001] The invention relates to the technical field of physical model test data analysis, and in particular to a method for evaluating tunnel surrounding rock characteristics during the service period of an engineering tunnel. Background Art

[0002] Anchor bolt and support technology has become a commonly used support method for surrounding rock control in coal mine tunnels. The mechanical response characteristics of support bodies such as anchor bolts and supports in tunnel stability analysis have important theoretical significance and engineering guidance value. However, since the anchor bolt support project in coal mine tunnels is a concealed project, there are many limitations in on-site engineering monitoring. In comparison, laboratory similar model tests have comprehensive advantages such as controllable test process, strong visibility of test phenomena, and quantifiable test results. They can truly reproduce the deformation and damage phenomena of the prototype tunnel and have become an important means to study the force response characteristics of support components such as tunnel anchor bolts. Since the 1980s, they have been widely used in the field of coal mine tunnel support research.

[0003] After the tunnel excavation is completed, the tunnel is in the original rock stress state. During the mining process of the working face, the static load of the tunnel increases; after mining, the load decreases again. At the same time, during the mining process, the tunnel will be subjected to impact loads. Therefore, the tunnel will experience repeated loading and unloading and frequent impact disturbances during service. In the existing tunnel support model test, it is difficult for similar models to strictly restore the static and dynamic loads of the engineering prototype according to the similarity ratio. At the same time, there is a lack of quantitative analysis methods for the anchor support system and the static and dynamic response characteristics. The depth of mining the response data of the support system during the full cycle of tunnel service is not enough, which makes it difficult to correspond the laboratory anchor support system with the surrounding rock deformation characteristics during the tunnel service in engineering practice. Summary of the invention

[0004] The present invention provides an evaluation method for the surrounding rock characteristics of an engineering tunnel during service, so as to solve the defect that it is difficult to correspond the anchor support system in the laboratory in the prior art with the deformation characteristics of the surrounding rock during the tunnel service in engineering practice, so as to realize the laboratory to truly reproduce the stress process and support characteristics of the engineering tunnel during service, and effectively analyze the acquired data to establish the connection between the support system response during the tunnel service and the deformation characteristics of the tunnel.

[0005] The present invention provides a method for evaluating the surrounding rock characteristics of an engineering tunnel during its service period, comprising the following steps S1 to S4.

[0006] S1. Prepare a physical model of the tunnel surrounding rock, and apply an initial static load to the physical model of the tunnel surrounding rock through a loading device.

[0007] S2, excavating the tunnel surrounding rock physical model of step S1, drilling anchor holes in the excavated tunnel, using anchors and gantry supports to support the tunnel, and providing support cylinders for the gantry supports to perform cylinder support.

[0008] S3. Set up monitoring devices to monitor the stress load and deformation displacement of the support cylinder, anchor rod and gantry support.

[0009] S4. Use a loading device to apply static and dynamic loads to the physical model of the tunnel surrounding rock to conduct static and dynamic experiments; monitor the load changes and deformation displacement changes of anchor rods, gantry supports and support cylinders during static and dynamic experiments to evaluate the homogeneity and stability of the tunnel surrounding rock.

[0010] According to a method for evaluating tunnel surrounding rock characteristics during tunnel service provided by the present invention, in step S4, using a loading device to apply static load and dynamic load to a tunnel surrounding rock physical model includes the following steps S41-S43.

[0011] S41. Maintain the displacement constraint in the axial direction of the excavated tunnel by the tunnel surrounding rock physical model, apply loads to the two sides and the top plate of the excavated tunnel, and increase the applied load value from the initial static load to the ultimate static load at a constant loading rate.

[0012] S42. The ultimate static load applied to the sides and top of the tunnel excavation physical model of the tunnel surrounding rock is unloaded at a constant rate until the load is unloaded to the post-mining static load.

[0013] S43. Apply impact dynamic load to the physical model of tunnel surrounding rock.

[0014] When conducting a static experiment on the physical model of the tunnel surrounding rock, step S41 and step S42 are repeated alternately; when conducting a dynamic experiment on the physical model of the tunnel surrounding rock, step S41, step S42 and step S43 are repeated alternately in sequence.

[0015] According to a method for evaluating the surrounding rock characteristics of an engineering tunnel during service provided by the present invention, in step S41, a gradient loading method is adopted in the process of increasing the applied load value from the initial static load to the ultimate static load at a constant loading rate, including a static load loading stage and a static load stabilization stage. In the static load loading stage, the applied load value increases from the initial static load value to the first intermediate static load value, or from one of the intermediate static load values ​​to the next intermediate static load value, at a constant loading rate; in the static load stabilization stage, the applied intermediate static load value does not increase, and the currently applied intermediate static load value is used for stabilization for a set time.

[0016] According to a method for evaluating the surrounding rock characteristics of an engineering tunnel during service provided by the present invention, in step S4, monitoring the load changes and deformation displacement changes of anchor rods, gantry supports and support cylinders during static and dynamic experiments includes: in the static load loading stage of the static experiment, monitoring the deformation of the anchor rod end and the anchor rod end load data, the gantry support deformation and load data, and the support cylinder load and displacement data; in the static load stabilization stage of the static experiment, monitoring the deformation of the anchor rod end and the anchor rod end load data, the gantry support deformation and load data, and the support cylinder load and displacement data; in the dynamic experiment impact load loading stage, monitoring the load and deformation data of the gantry support and the anchor rod end, and calculating the impulse and energy data.

[0017] According to a method for evaluating the characteristics of tunnel surrounding rock during the service of an engineering tunnel provided by the present invention, in the static load loading stage of the static experiment, based on the load and displacement data of the support cylinder, a support cylinder load-displacement curve is drawn, and a linear function is used for linear fitting to obtain a load-displacement fitting line of the support cylinder. The stiffness of the tunnel surrounding rock physical model and the stability of the tunnel surrounding rock are positively correlated with the fitting slope of the load-displacement curve of the support cylinder, the degree of crack development in the tunnel surrounding rock physical model is negatively correlated with the fitting goodness of the load-displacement fitting line of the support cylinder, and the stability of the tunnel surrounding rock is positively correlated with the fitting goodness of the load-displacement fitting line of the support cylinder.

[0018] In the static load stabilization stage of the static experiment, the displacement time history curve of the support cylinder was drawn based on the displacement data of the support cylinder, and a linear function was used for linear fitting to obtain the displacement time history fitting line of the support cylinder. The stiffness of the tunnel surrounding rock physical model and the stability of the tunnel surrounding rock were positively correlated with the absolute value of the fitting slope of the displacement time history curve of the support cylinder. The degree of crack development in the tunnel surrounding rock physical model was negatively correlated with the goodness of fit of the displacement time history fitting line of the support cylinder. The stability of the tunnel surrounding rock was positively correlated with the goodness of fit of the displacement time history fitting line of the support cylinder.

[0019] In the static load loading stage and static load stabilization stage of the static experiment, the load time history curve and deformation time history curve of the portal support / anchor were drawn based on the deformation and load data of the portal support / anchor, and linear fitting was performed using linear functions to obtain the load time history fitting line and deformation time history fitting line of the portal support / anchor. The stiffness of the tunnel surrounding rock physical model and the stability of the tunnel surrounding rock were positively correlated with the fitting slopes of the load time history curve and deformation time history curve of the portal support / anchor. The degree of crack development in the tunnel surrounding rock physical model was negatively correlated with the goodness of fit of the load time history fitting line or deformation time history fitting line of the portal support / anchor. The stability of the tunnel surrounding rock was positively correlated with the goodness of fit of the load time history fitting line or deformation time history fitting line of the portal support / anchor.

[0020] In the impact load loading stage of the dynamic experiment, after one impact load, the load time history curve of the anchor / gantry is drawn based on the load data of the anchor end / gantry, and the initial load value, load peak value and final load after impact of the anchor / gantry are obtained. The load growth rate of the anchor / gantry at any time is calculated, and the load growth rate time history curve of the anchor / gantry is drawn to obtain the maximum load growth rate, minimum load growth rate and average load growth rate of the anchor / gantry. The response of the anchor / gantry to the impact is positively correlated with the load peak value of the anchor / gantry, the final load after impact, the maximum load growth rate, the minimum load growth rate and the average load growth rate of the anchor / gantry, respectively.

[0021] In the impact load loading stage of the dynamic experiment, after one impact load, the impulse of the anchor end / gantry is calculated based on the load data of the anchor end / gantry, and the impulse time-history curve of the anchor / gantry is drawn to obtain the initial value of the impulse of the anchor / gantry, the impulse peak value and the final impulse after the impact, the impulse growth rate of the anchor / gantry at any time is calculated, and the impulse growth rate time-history curve of the anchor / gantry is drawn to obtain the maximum growth rate, minimum growth rate and average growth rate of the impulse of the anchor / gantry. The response of the anchor / gantry to the impact is positively correlated with the impulse peak value of the anchor / gantry, the final impulse after the impact, the maximum growth rate of the impulse, the minimum growth rate of the impulse, and the average growth rate of the impulse.

[0022] In the impact load loading stage of the dynamic experiment, after one impact load, the deformation time-history curve of the anchor / gantry is drawn based on the deformation data of the anchor end / gantry, and the initial deformation value, deformation peak value and final deformation after impact of the anchor / gantry are obtained. The deformation growth rate of the anchor / gantry at any time is calculated, and the deformation growth rate time-history curve of the anchor / gantry is drawn to obtain the maximum growth rate, minimum growth rate and average growth rate of the deformation of the anchor / gantry. The response of the anchor / gantry to the impact is positively correlated with the deformation peak value of the anchor / gantry, the final deformation after impact, the maximum growth rate, the minimum growth rate and the average growth rate of the deformation.

[0023] In the dynamic experiment impact load loading stage, after one impact load, the deformation absorption energy of the anchor end / gantry is calculated based on the load data and deformation data of the anchor end / gantry, and the deformation absorption energy time history curve of the anchor / gantry is drawn to obtain the initial value of the deformation absorption energy of the anchor / gantry, the deformation absorption energy peak value and the final deformation absorption energy after impact, the deformation absorption energy growth rate of the anchor / gantry at any time is calculated, and the deformation absorption energy growth rate time history curve of the anchor / gantry is drawn to obtain the maximum growth rate, minimum growth rate and average growth rate of the deformation absorption energy of the anchor / gantry. The response of the anchor / gantry to the impact is positively correlated with the deformation absorption energy peak value of the anchor / gantry, the final deformation absorption energy after impact, the maximum growth rate of the deformation absorption energy, the minimum growth rate of the deformation absorption energy and the average growth rate of the deformation absorption energy.

[0024] According to a method for evaluating the surrounding rock characteristics of an engineering tunnel during service provided by the present invention, the load-displacement fitting line of the support cylinder is obtained by linear fitting through the following formula 1: Formula 1, where Indicates the load data of the support cylinder loading stage, represents the fitted slope of the load-displacement curve, Indicates the displacement data of the support cylinder during loading phase, represents the fitting constant.

[0025] The displacement time history fitting line of the support cylinder is obtained by linear fitting through the following formula 2: Formula 2, where Indicates the displacement data of the support cylinder during the pressure stabilization stage. represents the fitting slope of the displacement time history curve, Indicates the pressure stabilization time of the support oil cylinder during the pressure stabilization stage. represents the fitting constant.

[0026] The load time history fitting line of the portal bracket is obtained by linear fitting through the following formula 3: Formula 3, where Indicates the load data of the portal support, represents the fitting slope of the load-time curve, represents the loading time of the portal support, represents the fitting constant.

[0027] The deformation time history fitting line of the portal bracket is obtained by linear fitting through the following formula 4: Formula 4, where Indicates the deformation data of the portal bracket. represents the fitting slope of the deformation time history curve, represents the loading time of the portal support, represents the fitting constant.

[0028] The load time history fitting line of the anchor rod is obtained by linear fitting through the following formula 5: Formula 5, where Indicates the load data at the end of the anchor rod. represents the fitting slope of the load-time curve, represents the loading time of the anchor, represents the fitting constant.

[0029] The deformation time history fitting line of the anchor rod is obtained by linear fitting through the following formula 6: Formula 6, where Indicates the deformation data of the anchor end. represents the fitting slope of the deformation time history curve, represents the loading time of the anchor, represents the fitting constant.

[0030] The load growth rate of the anchor / gantry support at any time is calculated by the following formula 7: Formula 7, where Indicates the load growth rate of the anchor / gantry support at any time, represents the load of the anchor / gantry support at time t+1 after the jth impact, represents the load of the anchor / gantry support at time t-1 after the jth impact, Represents the time difference between two data points.

[0031] The deformation growth rate of the anchor rod / gantry support at any time is calculated by the following formula 8: Formula 8, where Indicates the deformation growth rate of the anchor rod / gantry support at any time, represents the deformation of the anchor rod / gantry support at time t+1 after the jth impact, represents the deformation of the anchor rod / gantry support at time t-1 after the jth impact, Represents the time difference between two data points.

[0032] After an impact load, the impulse of the anchor end / gantry support is calculated by the following formula 9: Formula 9, where Indicates the impulse of the anchor end / gantry support, represents the load of the anchor / gantry support at time t+1 after the jth impact, represents the load of the anchor / gantry support at time t-1 after the jth impact, Represents the time difference between two data points.

[0033] The impulse growth rate of the anchor / gantry support at any time is calculated by the following formula: Formula 10, where Indicates the impulse growth rate of the anchor / gantry support at any time, represents the impulse of the anchor / gantry support at time t+1 after the jth impact, represents the impulse of the anchor / gantry support at time t-1 after the jth impact, Represents the time difference between two data points.

[0034] After an impact load, the deformation absorption energy of the anchor end / gantry support is calculated by the following formula 11: Formula 11, where Indicates the deformation absorption energy of the anchor end / gantry support, represents the load of the anchor / gantry support at time t+1 after the jth impact, represents the load of the anchor / gantry support at time t-1 after the jth impact, represents the deformation of the anchor rod / gantry support at time t+1 after the jth impact, It represents the deformation of the anchor rod / gantry support at time t-1 after the j-th impact.

[0035] The deformation absorption energy growth rate of the anchor rod / gantry support at any time is calculated by the following formula 12: Formula 12, where It indicates the growth rate of deformation absorption energy of anchor rod / gantry support at any time. represents the deformation absorption energy of the anchor rod / gantry support at time t+1 after the jth impact, represents the deformation absorption energy of the anchor rod / gantry support at time t-1 after the jth impact, Represents the time difference between two data points.

[0036] According to a method for evaluating the surrounding rock characteristics of an engineering tunnel during service provided by the present invention, for a support cylinder, in the static load loading stage of a static experiment, the load-displacement curve fitting slope increment, the load-displacement fitting line fitting goodness, and the maximum displacement of the support cylinder in two adjacent loading stages are used to obtain the load-displacement curve fitting slope increment, the load-displacement fitting line fitting goodness increment, and the maximum displacement increment of the support cylinder; in the static load stabilization stage of the static experiment, the displacement time history curve fitting slope increment, the displacement time history fitting line fitting goodness increment, and the maximum displacement of the support cylinder in two adjacent stabilization stages are used to obtain the displacement time history curve fitting slope increment, the displacement time history fitting line fitting goodness increment, and the maximum displacement increment of the support cylinder.

[0037] For the portal bracket, the fitting slope of the load-time history curve and deformation time-history curve of the portal bracket in two adjacent loading stages or pressure stabilization stages, the goodness of fit of the load-time history fitting line and deformation time-history fitting line of the portal bracket, the maximum load of the portal bracket, and the maximum deformation of the portal bracket are obtained to obtain the fitting slope increment of the load-time history curve and deformation time-history curve of the portal bracket, the fitting goodness increment of the load-time history fitting line and deformation time-history fitting line of the portal bracket, the maximum load increment of the portal bracket, and the maximum deformation increment of the portal bracket.

[0038] For anchor rods, the fitting slope of the load-history curve and deformation-history curve of the anchor rod in two adjacent loading stages or pressure stabilization stages, the goodness of fit of the load-history fitting line or the deformation-history fitting line of the anchor rod, the maximum load at the end of the anchor rod, and the maximum deformation at the end of the anchor rod are obtained to obtain the fitting slope increment of the load-history curve and deformation-history curve of the anchor rod, the fitting goodness increment of the load-history fitting line or the deformation-history fitting line of the anchor rod, the maximum load increment at the end of the anchor rod, and the maximum deformation increment at the end of the anchor rod.

[0039] By assigning different weights to the data increments of the above-mentioned support cylinders, gantry supports and anchor rods, the change in the stability of the tunnel confining pressure can be quantitatively characterized.

[0040] According to a method for evaluating the surrounding rock characteristics of a tunnel during the service period of an engineering tunnel provided by the present invention, the tunnel confining pressure stability in the static load loading stage or the pressure stabilization stage of the static experiment is positively correlated with the data increments of the above-mentioned support cylinder, gantry support, and anchor rod, respectively, and the change in the tunnel confining pressure stability is quantitatively characterized by the following formula 13: Formula 13, where Indicates the stability of the tunnel confining pressure, Indicates the data increments of the support cylinder, gantry support, and anchor rod. represents the number of increments, represents the weight of each increment, and .

[0041] According to a method for evaluating the surrounding rock characteristics of a tunnel during the service period of an engineering tunnel provided by the present invention, during the impact load loading stage of a dynamic experiment, the anchor rod / gantry support obtains the corresponding increments of two adjacent impact loads through the load peak values ​​of two adjacent impact loads, the final load after the impact, the maximum load growth rate, the minimum load growth rate, the average load growth rate, the impulse peak value, the final impulse after the impact, the maximum impulse growth rate, the minimum impulse growth rate, the average impulse growth rate, the deformation peak value, the final deformation after the impact, the maximum deformation growth rate, the minimum deformation growth rate, the average deformation growth rate, the deformation absorption energy peak value, the final deformation absorption energy after the impact, the maximum deformation absorption energy growth rate, the minimum deformation absorption energy growth rate, and the average deformation absorption energy growth rate, and the corresponding increments of the two adjacent impact loads are positively correlated. The response of the anchor rod / gantry support to the impact is positively correlated with the corresponding increments of the two adjacent impact loads.

[0042] According to a method for evaluating the characteristics of surrounding rock of an engineering tunnel during service provided by the present invention, the homogeneity and stability of the surrounding rock are evaluated by calculating the standard deviation, variance and range of various mechanical response parameters of the anchor rod / gantry support during the impact load loading stage of the dynamic experiment. The standard deviation, variance and range of various mechanical response parameters are negatively correlated with the homogeneity and stability of the surrounding rock.

[0043] The standard deviation of a mechanical response parameter is calculated by the following formula 14: Formula 14, where represents the standard deviation, m represents the number of anchors / gantry supports, x represents the mechanical response parameter value, is the mean value of the mechanical response parameters corresponding to m anchors / gantry supports.

[0044] The variance of a mechanical response parameter is calculated by the following formula: Formula 15, where represents the variance, m represents the number of anchors / gantry supports, x represents the mechanical response parameter value, is the mean value of the mechanical response parameters corresponding to m anchors / gantry supports.

[0045] The range of a certain mechanical response parameter is calculated by the following formula: Formula 16, where Indicates extremely poor, is the maximum value of the mechanical response parameter corresponding to m anchors / gantry supports, is the minimum value of the mechanical response parameter corresponding to m anchors / gantry supports.

[0046] The various mechanical response parameters include load peak, final load after impact, maximum load growth rate, minimum load growth rate, average load growth rate, impulse peak, final impulse after impact, maximum impulse growth rate, minimum impulse growth rate, average impulse growth rate, deformation peak, final deformation after impact, maximum deformation growth rate, minimum deformation growth rate, average deformation growth rate, deformation absorption energy peak, final deformation absorption energy after impact, maximum deformation absorption energy growth rate, minimum deformation absorption energy growth rate, and average deformation absorption energy growth rate.

[0047] The evaluation method of tunnel surrounding rock characteristics during the service period of an engineering tunnel provided by the present invention is used to truly reproduce the stress process and support characteristics of the engineering tunnel during the service period in the laboratory, and effectively analyze the acquired data, in order to establish a connection between the response of the support system during the service period of the tunnel and the deformation state of the tunnel. Dynamic and static load parameters are applied through a tunnel surrounding rock physical model consistent with the engineering site, and data is acquired for analysis. On the one hand, the engineering practice process can be better restored, and the consistency of the model process and the engineering scene can be ensured, thereby improving the authenticity and reliability of the simulation results, and better guiding the design of coal mine tunnel support schemes. On the other hand, the deformation and failure morphology of the tunnel can be inferred according to the response characteristics of support components such as anchor rods. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 It is a schematic flow chart of the method for evaluating the characteristics of surrounding rock of an engineering tunnel during its service period provided by the present invention.

[0050] Figure 2 It is the linear fitting diagram of the load-displacement curve of the support cylinder during the static load loading stage of the static experiment.

[0051] Figure 3 It is the linear fitting diagram of the displacement time history curve of the support cylinder in the static load stabilization stage of the static experiment.

[0052] Figure 4 It is the linear fitting diagram of the portal support load time history curve in the static load loading stage and the pressure stabilization stage of the static experiment.

[0053] Figure 5 It is the linear fitting diagram of the deformation time history curve of the portal bracket in the static load loading stage and the pressure stabilization stage of the static experiment.

[0054] Figure 6 It is the linear fitting diagram of the anchor load time history curve in the static load loading stage and the stabilizing pressure stage of the static experiment.

[0055] Figure 7 It is the linear fitting diagram of the anchor deformation time history curve in the static load loading stage and the stabilization pressure stage of the static experiment.

[0056] Figure 8 It is the time history curve of anchor load in the dynamic experiment impact load loading stage.

[0057] Figure 9It is the time history curve of anchor load growth rate in the impact load loading stage of dynamic experiment. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] Combine the following Figure 1~Figure 9 The present invention describes a method for evaluating the surrounding rock characteristics of an engineering tunnel during its service period.

[0060] One embodiment of the present invention provides a method for evaluating the characteristics of surrounding rock in an engineering tunnel during service. Figure 1 As shown, the process includes the following steps S1 to S4.

[0061] S1. Prepare a physical model of the tunnel surrounding rock, and apply an initial static load to the physical model of the tunnel surrounding rock through a loading device.

[0062] S2, excavating the tunnel surrounding rock physical model of step S1, drilling anchor holes in the excavated tunnel, using anchors and gantry supports to support the tunnel, and setting support cylinders for the gantry supports in the excavated tunnel to perform cylinder support.

[0063] S3. Set up monitoring devices, use force gauges to monitor the force loads on anchor rods and gantry supports, and use non-contact detectors to monitor the deformation and displacement of anchor rods and gantry supports.

[0064] S4. Use a loading device to apply static and dynamic loads to the physical model of the tunnel surrounding rock to conduct static and dynamic experiments; monitor the load changes and deformation displacement changes of anchor rods, gantry supports and support cylinders during static and dynamic experiments to evaluate the homogeneity and stability of the tunnel surrounding rock.

[0065] Specifically, the model material ratio is determined according to the geometric similarity ratio n, mechanical similarity ratio q and bulk density similarity ratio m, and the tunnel similarity material model is made and maintained; after the model maintenance is completed, the physical model is placed in the loading device, and the model adopts a displacement boundary in the axial direction of the tunnel to limit its axial deformation; stress boundaries are applied to the two sides and the top plate of the model, and the applied stress value is the initial static load, which is the product of the original rock stress of the tunnel at the engineering site and the mechanical similarity ratio q. After the initial static load is applied, the tunnel is excavated. The tunnel size is determined according to the tunnel size at the engineering site and the geometric similarity ratio n. Then the excavated tunnel is supported, and the support material selection and support density are determined by the engineering site size and the geometric similarity ratio n. According to the simulated anchor length, the anchor hole is drilled in the model using a handheld electric drill, and the anchoring method is selected according to engineering practice, including end anchor, the anchoring section is shorter than 1 / 3 of the anchor length; the extension anchor, the anchoring section is between 0.3 and 0.9 of the anchor length. Determine the amount of anchoring agent based on the anchor length, anchoring method, and anchor hole diameter d. For example, if you choose an end anchor, the amount of anchoring agent is V Should meet If you choose to lengthen the anchor, the amount of anchoring agent V Should meet . Place the anchoring agent at the bottom of the anchor hole and insert the simulated anchor into the anchor hole. During operation, ensure that the anchor is located in the center of the anchor hole. After the anchor is stabilized by the anchor, install the simulated tray, nut, etc., and then apply the preload force to complete the preload force of the anchor. The real-time preload force during the application process can be obtained by installing an anchor dynamometer at the tail of the anchor.

[0066] Then, a gantry support is used in the tunnel for tunnel support, and a support cylinder is set on the gantry support in the excavated tunnel for cylinder support. The hydraulic system of the gantry support is adjusted to apply initial support force. After the installation of the anchor rod and the adjustment gantry is completed, the test device needs to be installed, and the force load of the anchor rod and the gantry support is monitored by a dynamometer, and the deformation displacement of the anchor rod and the gantry support is monitored by a non-contact detector. After the installation of the above model and support structure is completed, the loading device is used to apply static and dynamic loads to the physical model of the tunnel surrounding rock to conduct static and dynamic experiments to obtain the deformation characteristics of the anchor rod and the gantry support during the service period of the engineering tunnel.

[0067] It can be understood that the evaluation method of the surrounding rock characteristics of the tunnel during the service period of the engineering tunnel in this embodiment is used to truly reproduce the stress process and support characteristics of the engineering tunnel during the service period in the laboratory, and effectively analyze the acquired data, in order to establish the connection between the support system response and the deformation state of the tunnel during the service period. By applying dynamic and static load parameters through the tunnel surrounding rock physical model consistent with the engineering site, and acquiring data for analysis, on the one hand, the engineering practice process can be better restored, and the consistency of the model process and the engineering scene can be ensured, thereby improving the authenticity and reliability of the simulation results, and better guiding the design of coal mine tunnel support schemes; on the other hand, the deformation and failure morphology of the tunnel can be inferred based on the response characteristics of support components such as anchors.

[0068] In some embodiments of a method for evaluating tunnel surrounding rock characteristics during service of an engineering tunnel of the present invention, in step S4, applying static load and dynamic load to the tunnel surrounding rock physical model using a loading device includes the following steps S41 to S43.

[0069] S41. Maintain the displacement constraint in the axial direction of the excavated tunnel by the tunnel surrounding rock physical model, apply loads to the two sides and the top plate of the excavated tunnel, and increase the applied load value from the initial static load to the ultimate static load at a constant loading rate.

[0070] Initial static load ,in is the original rock stress of the tunnel at the project site, q is the mechanical similarity ratio; the ultimate static load ,in is the tunnel support pressure at the engineering site, and q is the mechanical similarity ratio.

[0071] In the process of increasing the applied load value from the initial static load to the ultimate static load at a constant loading rate, a gradient loading method is adopted, including a static load loading stage and a static load stabilization stage. In the static load loading stage, the applied load value increases from the initial static load value to the first intermediate static load value, or from one of the intermediate static load values ​​to the next intermediate static load value, at a constant loading rate; in the static load stabilization stage, the applied intermediate static load value does not increase, and the current applied intermediate static load value is used for stabilization for a set time.

[0072] S42. The ultimate static load applied to the sides and top of the tunnel excavation physical model of the tunnel surrounding rock is unloaded at a constant rate until the load is unloaded to the post-mining static load.

[0073] Post-harvest static load ,in is the measured pressure on the roof and sides of the tunnel after mining at the working face at the project site, and q is the mechanical similarity ratio.

[0074] S43. Apply impact dynamic load to the physical model of tunnel surrounding rock. Impact dynamic load energy ,in is the dynamic load borne by the tunnel at the engineering site, and q is the mechanical similarity ratio.

[0075] When conducting a static experiment on the physical model of the tunnel surrounding rock, step S41 and step S42 are repeated alternately; when conducting a dynamic experiment on the physical model of the tunnel surrounding rock, step S41, step S42 and step S43 are repeated alternately in sequence.

[0076] It can be understood that in step S4, monitoring the load changes and deformation and displacement changes of the anchor rods, gantry supports and supporting cylinders during static and dynamic experiments includes: in the static load loading stage of the static experiment, monitoring the deformation of the anchor rod end and the anchor rod end load data, the gantry support deformation and load data, and the supporting cylinder load and displacement data; in the static load stabilization stage of the static experiment, monitoring the deformation of the anchor rod end and the anchor rod end load data, the gantry support deformation and load data, and the supporting cylinder load and displacement data; in the impact load loading stage of the dynamic experiment, monitoring the load and deformation data of the gantry support and the anchor rod end, and calculating the impulse and energy data.

[0077] Specifically, in the static test stage, the loading cylinder load and displacement data, the gantry support deformation and load data, the anchor end deformation and anchor end load data can be obtained from the initial static load to the ultimate static load.

[0078] In the static load loading stage of the static experiment, the load-displacement curve of the support cylinder was drawn based on the load and displacement data of the support cylinder, and a linear function was used for linear fitting to obtain the load-displacement fitting line of the support cylinder. The stiffness of the tunnel surrounding rock physical model and the stability of the tunnel surrounding rock were positively correlated with the fitting slope of the load-displacement curve of the support cylinder. The degree of crack development in the tunnel surrounding rock physical model was negatively correlated with the goodness of fit of the load-displacement fitting line of the support cylinder, and the stability of the tunnel surrounding rock was positively correlated with the goodness of fit of the load-displacement fitting line of the support cylinder.

[0079] See also Figure 2 As shown in the figure, in the static load i-th loading stage of the static experiment, the load-displacement curve of the support cylinder is drawn, and the load-displacement fitting line of the support cylinder is obtained by linear fitting through the following formula 1: Formula 1, where Indicates the load data of the support cylinder loading stage, represents the fitted slope of the load-displacement curve, Indicates the displacement data of the support cylinder during loading phase, represents the fitting constant, and the goodness of fit is recorded as . The larger the value, the greater the stiffness of the physical model and the better the stability of the tunnel surrounding rock. Find the maximum displacement of each level of loading cylinder , the physical model stiffness and Negative correlation, that is, the stability of the surrounding rock of the tunnel is Negative correlation.

[0080] In the static load stabilization stage of the static experiment, the displacement time history curve of the support cylinder was drawn based on the displacement data of the support cylinder, and a linear function was used for linear fitting to obtain the displacement time history fitting line of the support cylinder. The stiffness of the tunnel surrounding rock physical model and the stability of the tunnel surrounding rock were positively correlated with the absolute value of the fitting slope of the displacement time history curve of the support cylinder. The degree of crack development in the tunnel surrounding rock physical model was negatively correlated with the goodness of fit of the displacement time history fitting line of the support cylinder. The stability of the tunnel surrounding rock was positively correlated with the goodness of fit of the displacement time history fitting line of the support cylinder.

[0081] See also Figure 3 As shown in the figure, in the static load i-level stabilization stage of the static experiment, since the load of the support cylinder remains constant, but the displacement of the cylinder is not constant, the displacement time history curve of the support cylinder is drawn, and the displacement time history fitting line of the support cylinder is obtained by linear fitting through the following formula 2: Formula 2, where Indicates the displacement data of the support cylinder during the pressure stabilization stage. represents the fitting slope of the displacement time history curve, Indicates the pressure stabilization time of the support oil cylinder during the pressure stabilization stage. represents the fitting constant, and the goodness of fit is recorded as .like A positive value indicates that the cylinder is extended and the model specimen is compressed. A negative value indicates that the cylinder is retracted and the model specimen is expanding. The larger the absolute value, the faster the cylinder expansion and contraction rate, indicating that the specimen has greater stiffness and the tunnel surrounding rock stability is better. Find the maximum displacement of the cylinder in each stage of pressure stabilization , the physical model stiffness and Negative correlation, that is, the stability of the surrounding rock of the tunnel is Negative correlation.

[0082] In the static load loading stage and static load stabilization stage of the static experiment, the load time history curve and deformation time history curve of the portal support / anchor were drawn based on the deformation and load data of the portal support / anchor, and linear fitting was performed using linear functions to obtain the load time history fitting line and deformation time history fitting line of the portal support / anchor. The stiffness of the tunnel surrounding rock physical model and the stability of the tunnel surrounding rock were positively correlated with the fitting slopes of the load time history curve and deformation time history curve of the portal support / anchor. The degree of crack development in the tunnel surrounding rock physical model was negatively correlated with the goodness of fit of the load time history fitting line or deformation time history fitting line of the portal support / anchor. The stability of the tunnel surrounding rock was positively correlated with the goodness of fit of the load time history fitting line or deformation time history fitting line of the portal support / anchor.

[0083] The analysis of the deformation and load data of the portal bracket during the static test phase is carried out in the following way.

[0084] See also Figure 4 As shown in the figure, in the i-th loading stage, the load time history curve of the portal bracket is drawn and fitted with a linear function. , where Indicates the load data of the portal support, represents the fitting slope of the load-time curve, represents the loading time of the portal support, represents the fitting constant, and the goodness of fit is , The larger the value, the greater the stiffness of the physical model and the better the stability of the tunnel surrounding rock. Negative correlation, tunnel surrounding rock stability and Positive correlation, goodness of fit The lower it is, the higher the degree of crack development, that is, the more cracks there are, the worse the stability of the tunnel surrounding rock.

[0085] See also Figure 5 As shown in the figure, in the i-th loading stage, the deformation time history curve of the portal bracket is drawn and fitted with a linear function. , where Indicates the deformation data of the portal bracket. represents the fitting slope of the deformation time history curve, represents the loading time of the portal support, represents the fitting constant, and the goodness of fit is . The larger the value, the greater the stiffness of the physical model and the better the stability of the tunnel surrounding rock. Negative correlation, tunnel surrounding rock stability and Positive correlation, goodness of fit The lower it is, the higher the degree of crack development, that is, the more cracks there are, the worse the stability of the tunnel surrounding rock.

[0086] Find the maximum load of the bracket at each loading stage and maximum displacement , the physical model stiffness and Negative correlation, that is, the stability of the surrounding rock of the tunnel is Negative correlation, the degree of response of the bracket to the loading process and Positive correlation.

[0087] See again Figure 4 As shown in the figure, in the i-th stage of voltage stabilization, the load time history curve of the portal support is drawn and fitted with a linear function. , where Indicates the load data of the portal support, represents the fitting slope of the load-time curve, represents the loading time of the portal support, represents the fitting constant, and the goodness of fit is . The larger the value, the greater the stiffness of the physical model and the better the stability of the tunnel surrounding rock. Negative correlation, tunnel surrounding rock stability and Positive correlation, goodness of fit The lower it is, the higher the degree of crack development, that is, the more cracks there are, the worse the stability of the tunnel surrounding rock.

[0088] See again Figure 5 As shown in the figure, in the i-th stage of voltage stabilization, the deformation time history curve of the portal bracket is drawn and fitted with a linear function. , where Indicates the deformation data of the portal bracket. represents the fitting slope of the deformation time history curve, represents the loading time of the portal support, represents the fitting constant, and the goodness of fit is . The larger the value, the greater the stiffness of the physical model and the better the stability of the tunnel surrounding rock. Negative correlation, tunnel surrounding rock stability and Positive correlation, goodness of fit The lower it is, the higher the degree of crack development, that is, the more cracks there are, the worse the stability of the tunnel surrounding rock.

[0089] Find the maximum load of the bracket at each stage of stabilization and maximum displacement , the physical model stiffness and Negative correlation, that is, the stability of the surrounding rock of the tunnel is Negative correlation, the degree of response of the bracket to the loading process and Positive correlation.

[0090] The analysis of anchor deformation and load data in the static test phase is consistent with the analysis of the deformation and load data of the portal support mentioned above, so it will not be described in detail here. Figure 6 and Figure 7 The linear fitting diagrams of the load time history curve and the linear fitting diagrams of the deformation time history curve of the anchor rod at different stages of the static experiment are respectively illustrated. The specific process can be found in the analysis process of the deformation and load data of the above-mentioned portal bracket.

[0091] In the dynamic experiment impact load loading stage, the anchor end load, deformation and other data after the jth impact are recorded, and then the impulse, energy, etc. are calculated. Specifically, after an impact load, based on the load data of the anchor end / portal support, the load time history curve of the anchor / portal support is drawn to obtain the initial load value, load peak value and final load after impact of the anchor / portal support, calculate the load growth rate of the anchor / portal support at any time, draw the load growth rate time history curve of the anchor / portal support, and obtain the maximum load growth rate, minimum load growth rate and average load growth rate of the anchor / portal support. The response of the anchor / portal support to the impact is positively correlated with the load peak value of the anchor / portal support, the final load after impact, the maximum load growth rate, the minimum load growth rate and the average load growth rate of the anchor / portal support.

[0092] Take the data analysis of the anchor bolt in the dynamic test impact load loading stage as an example, see Figure 8 As shown in the figure, after the jth impact, the anchor load time history curve is drawn to obtain the anchor load peak value and the final load after impact The stage where the anchor load increases with the impact time is the load rise stage, connecting the initial load value and the maximum load The slope of the connecting line is recorded as the average growth rate of the anchor load after the jth impact The load growth rate of the anchor at any time is calculated by the following formula: , where represents the load of the anchor at time t+1 after the jth impact, represents the load of the anchor at time t-1 after the jth impact, represents the time difference between two data points, which is one-tenth of the sampling frequency. Draw the time history curve of the anchor load growth rate and find the maximum value, that is, the maximum growth rate of the anchor load, recorded as Similarly, the minimum increase rate of anchor load can be obtained, which is recorded as After the jth impact, the anchor bolt's impact response is , , , , Positive correlation.

[0093] In the impact load loading stage of the dynamic experiment, after one impact load, the impulse of the anchor end / gantry is calculated based on the load data of the anchor end / gantry, and the impulse time-history curve of the anchor / gantry is drawn to obtain the initial value of the impulse of the anchor / gantry, the impulse peak value and the final impulse after the impact, the impulse growth rate of the anchor / gantry at any time is calculated, and the impulse growth rate time-history curve of the anchor / gantry is drawn to obtain the maximum growth rate, minimum growth rate and average growth rate of the impulse of the anchor / gantry. The response of the anchor / gantry to the impact is positively correlated with the impulse peak value of the anchor / gantry, the final impulse after the impact, the maximum growth rate of the impulse, the minimum growth rate of the impulse, and the average growth rate of the impulse.

[0094] Take the data analysis of the anchor bolt in the dynamic test impact load loading stage as an example, see Figure 9 As shown in the figure, after the jth impact, the deformation time history curve of the anchor rod is drawn to obtain the peak value of the anchor rod deformation. And the final deformation after impact The stage where the bolt deformation increases with the impact time is the tensile deformation stage, which connects the initial deformation value with the maximum deformation value. The slope of the connecting line is recorded as the average growth rate of anchor deformation after the jth impact The deformation growth rate of the anchor at any time is calculated by the following formula: , where represents the deformation of the anchor at time t+1 after the jth impact, represents the deformation of the anchor at time t-1 after the jth impact, represents the time difference between two data points, which is one-tenth of the sampling frequency. Draw the time history curve of anchor deformation growth rate and find the maximum value, that is, the maximum growth rate of anchor deformation, recorded as Similarly, the minimum increase rate of anchor load can be obtained, which is recorded as After the jth impact, the anchor bolt's impact response is , , , , Positive correlation.

[0095] In the impact load loading stage of the dynamic experiment, after one impact load, the deformation time-history curve of the anchor / gantry is drawn based on the deformation data of the anchor end / gantry, and the initial deformation value, deformation peak value and final deformation after impact of the anchor / gantry are obtained. The deformation growth rate of the anchor / gantry at any time is calculated, and the deformation growth rate time-history curve of the anchor / gantry is drawn to obtain the maximum growth rate, minimum growth rate and average growth rate of the deformation of the anchor / gantry. The response of the anchor / gantry to the impact is positively correlated with the deformation peak value of the anchor / gantry, the final deformation after impact, the maximum growth rate, the minimum growth rate and the average growth rate of the deformation.

[0096] Taking the data analysis of the anchor rod in the dynamic experimental impact load loading stage as an example, after the jth impact, the anchor rod impulse at any time , , where represents the load of the anchor at time t+1 after the jth impact, represents the load of the anchor at time t-1 after the jth impact, Represents the time difference between two data points. After the jth impact, draw the anchor impulse time history curve to obtain the anchor impulse peak value and the final impulse after impact The stage where the impulse of the anchor increases with the impact time is the impulse growth stage, which connects the initial value of the impulse with the maximum impulse. The slope of the connecting line is recorded as the average growth rate of the bolt impulse after the jth impact The impulse growth rate of the anchor at any time is calculated by the following formula: , where represents the impulse of the anchor at time t+1 after the jth impact, represents the impulse of the anchor at time t-1 after the jth impact, represents the time difference between two data points, which is one-tenth of the sampling frequency. Draw the time history curve of the anchor impulse growth rate and find the maximum value, that is, the maximum growth rate of the anchor impulse, recorded as Similarly, the minimum impulse speed increase of the anchor bolt can be obtained, which is recorded as After the jth impact, the anchor bolt's impact response is , , , , Positive correlation.

[0097] In the dynamic experiment impact load loading stage, after one impact load, the deformation absorption energy of the anchor end / gantry is calculated based on the load data and deformation data of the anchor end / gantry, and the deformation absorption energy time history curve of the anchor / gantry is drawn to obtain the initial value of the deformation absorption energy of the anchor / gantry, the deformation absorption energy peak value and the final deformation absorption energy after impact, the deformation absorption energy growth rate of the anchor / gantry at any time is calculated, and the deformation absorption energy growth rate time history curve of the anchor / gantry is drawn to obtain the maximum growth rate, minimum growth rate and average growth rate of the deformation absorption energy of the anchor / gantry. The response of the anchor / gantry to the impact is positively correlated with the deformation absorption energy peak value of the anchor / gantry, the final deformation absorption energy after impact, the maximum growth rate of the deformation absorption energy, the minimum growth rate of the deformation absorption energy and the average growth rate of the deformation absorption energy.

[0098] Taking the data analysis of the anchor rod in the dynamic test impact load loading stage as an example, after the jth impact, the energy absorbed by the anchor rod due to deformation at any time is , , Chinese represents the load of the anchor at time t+1 after the jth impact, represents the load of the anchor at time t-1 after the jth impact, represents the deformation of the anchor rod at time t+1 after the jth impact, It represents the deformation of the anchor rod at time t-1 after the jth impact. After the jth impact, the time history curve of anchor rod deformation and energy absorption is plotted to obtain the peak value of anchor rod deformation and energy absorption. And the final deformation absorption energy after impact The stage where the deformation absorption energy of the anchor increases with the impact time is the absorption energy stage, which connects the initial value of the deformation absorption energy with the maximum deformation absorption energy. The slope of the connecting line is recorded as the average growth rate of anchor deformation absorption energy after the jth impact The deformation absorption energy growth rate of the anchor at any time is calculated by the following formula: , where represents the deformation absorption energy of the anchor rod at time t+1 after the jth impact, represents the deformation absorption energy of the anchor rod at time t-1 after the jth impact, represents the time difference between two data points, which is one of the sampling frequency. Draw the time history curve of anchor deformation absorption energy growth rate, find the maximum value, that is, the maximum growth rate of anchor deformation absorption energy, recorded as Similarly, the minimum growth rate of anchor deformation absorption energy can be obtained, which is expressed as After the jth impact, the anchor bolt's impact response is , , , , Positive correlation.

[0099] The analysis of the deformation, load, impulse and deformation absorption energy data of the portal support in the dynamic experiment stage is consistent with the analysis of the deformation, load, impulse and deformation absorption energy data of the above-mentioned anchor rods, and will not be described in detail here. For details, please refer to the analysis process of the deformation, load, impulse and deformation absorption energy data of the above-mentioned anchor rods.

[0100] In other embodiments of the method for evaluating the surrounding rock characteristics of an engineering tunnel during service of the present invention, for the support cylinder, in the static load loading stage of the static experiment, the load-displacement curve fitting slope increment, the load-displacement fitting line fitting goodness, and the maximum displacement of the support cylinder in two adjacent loading stages are used to obtain the load-displacement curve fitting slope increment, the load-displacement fitting line fitting goodness increment, and the maximum displacement increment of the support cylinder; in the static load stabilization stage of the static experiment, the displacement time history curve fitting slope increment, the displacement time history fitting line fitting goodness increment, and the maximum displacement of the support cylinder in two adjacent stabilization stages are used to obtain the displacement time history curve fitting slope increment, the displacement time history fitting line fitting goodness increment, and the maximum displacement increment of the support cylinder.

[0101] Specifically, the deformation stiffness of the cylinder in two adjacent loading stages is compared to calculate the i Cylinder deformation stiffness increment during the loading stage Compare the goodness of fit of the cylinder load-displacement curves in two adjacent loading stages and calculate the i The fitting goodness increment of the cylinder load-displacement curve in the loading stage D R 油缸Fi =R 油缸Fi -R 油缸Fi-1 Compare the maximum displacement of the cylinder in two adjacent loading stages and calculate the i Maximum displacement increment of the cylinder during the loading stage Compare the deformation stiffness of the oil cylinder in two adjacent pressure stabilization stages and calculate the i The increment of deformation stiffness of the oil cylinder during the pressure stabilization stage Δk 稳压油缸li = k 稳压油缸li - k 稳压油缸li-1 Compare the fitting goodness of the cylinder displacement time history curves in two adjacent pressure stabilization stages and calculate the i The fitting goodness increment of the cylinder displacement time history curve in the stage of loading D R 稳压油缸li =R 稳压油缸li -R 稳压油缸li-1 Compare the maximum displacement of the cylinder in two consecutive pressure stabilization stages and calculate the i Maximum displacement increment of the cylinder during the pressure stabilization stage Δl稳压油缸imax = l 稳压油缸imax - l 稳压油缸i－1max .

[0102] For the portal bracket, the fitting slope of the load-time history curve and deformation time-history curve of the portal bracket in two adjacent loading stages or pressure stabilization stages, the goodness of fit of the load-time history fitting line and deformation time-history fitting line of the portal bracket, the maximum load of the portal bracket, and the maximum deformation of the portal bracket are obtained to obtain the fitting slope increment of the load-time history curve and deformation time-history curve of the portal bracket, the fitting goodness increment of the load-time history fitting line and deformation time-history fitting line of the portal bracket, the maximum load increment of the portal bracket, and the maximum deformation increment of the portal bracket.

[0103] Specifically, the load stiffness of the portal bracket in two adjacent loading stages is compared to calculate the i Load stiffness increment of portal support during the loading stage Δk 加载支架Fi = k 加载支架Fi - k 加载支架Fi-1 Compare the deformation stiffness of the portal bracket in two adjacent loading stages and calculate the i Deformation stiffness increment of portal support during loading stage Δk 加载支架li = k 加载支架li - k 加载支架li-1 Compare the fitting goodness of the load time history curve of the portal support in two adjacent loading stages and calculate the i Goodness increment of fitting of load time history curve of portal support in stage of loading D R 加载支架Fi =R 加载支架Fi -R 加载支架Fi-1 Compare the fitting goodness of the deformation time history curve of the portal bracket in two adjacent loading stages and calculate the i Goodness increment of fitting of deformation time history curve of portal support in stage of loading D R 加载支架li =R 加载支架li -R 加载支架li-1 Compare the maximum load of the portal support in two adjacent loading stages and calculate the i Maximum load increment of portal support during loading stage ΔF 加载支架imax = F 加载支架imax - F 加载支架i-1max Compare the maximum load of the portal support in two adjacent loading stages and calculate the i Maximum load increment of portal support during loading stage Δl加载支架imax = l 加载支架imax - l 加载支架i-1max Compare the load stiffness of the portal support in two adjacent pressure stabilization stages and calculate the i The load stiffness increment of the portal support during the pressure stabilization stage Δk 稳压支架Fi = k 稳压支架Fi - k 稳压支架Fi-1 Compare the deformation stiffness of the portal support in two adjacent pressure stabilization stages and calculate the i Deformation stiffness increment of portal support during the pressure stabilization stage Δk 稳压支架li = k 稳压支架li - k 稳压支架li-1 Compare the fitting goodness of the portal support load time history curves in two adjacent pressure stabilization stages and calculate the i Goodness increment of fitting of portal support load time history curve in the first stage of pressure stabilization D R 稳压支架Fi =R 稳压支架Fi -R 稳压支架Fi-1 Compare the fitting goodness of the deformation time history curves of the portal support in two adjacent pressure stabilization stages and calculate the i The fitting goodness increment of the deformation time history curve of the portal support in the first stage of pressure stabilization D R 稳压支架li =R 稳压支架li -R 稳压支架li-1 Compare the maximum load of the portal support in two consecutive pressure stabilization stages and calculate the i Maximum load increment of portal support during the first stage of voltage stabilization ΔF 稳压支架imax = F 稳压支架imax - F 稳压支架i-1max Compare the maximum load of the portal support in two consecutive pressure stabilization stages and calculate the i Maximum load increment of portal support during the first stage of voltage stabilization Δl 稳压支架imax = l 稳压支架imax - l 稳压支架i-1max .

[0104] For anchor rods, the fitting slope of the load-history curve and deformation-history curve of the anchor rod in two adjacent loading stages or pressure stabilization stages, the goodness of fit of the load-history fitting line or the deformation-history fitting line of the anchor rod, the maximum load at the end of the anchor rod, and the maximum deformation at the end of the anchor rod are obtained to obtain the fitting slope increment of the load-history curve and deformation-history curve of the anchor rod, the fitting goodness increment of the load-history fitting line or the deformation-history fitting line of the anchor rod, the maximum load increment at the end of the anchor rod, and the maximum deformation increment at the end of the anchor rod.

[0105] Specifically, compare the anchor load stiffness in two adjacent loading stages and calculate the i Anchor load stiffness increment during the loading stage Δk 加载锚杆Fi = k 加载锚杆Fi - k 加载锚杆Fi-1 Compare the deformation stiffness of the anchor rod in two adjacent loading stages and calculate the i Anchor deformation stiffness increment during the loading stage Δk 加载锚杆li = k 加载锚杆li - k 加载锚杆li-1 Compare the goodness of fit of the anchor load time history curves in two adjacent loading stages and calculate the i Goodness increment of anchor load time history curve fitting in the first loading stage D R 加载锚杆Fi =R 加载锚杆Fi -R 加载锚杆Fi-1 Compare the fitting goodness of the anchor deformation time history curves in two adjacent loading stages and calculate the i Goodness increment of fitting of anchor deformation time history curve in the first loading stage D R 加载锚杆li =R 加载锚杆li -R 加载锚杆li-1 Compare the maximum load of the anchor rod in two adjacent loading stages and calculate the i Maximum load increment of anchor bolt during the loading stage ΔF 加载锚杆imax = F 加载锚杆imax - F 加载锚杆i-1max Compare the maximum load of the anchor rod in two adjacent loading stages and calculate the i Maximum load increment of anchor bolt during the loading stage Δl 加载锚杆imax = l 加载锚杆imax - l 加载锚杆i-1max Compare the anchor load stiffness of two adjacent stabilization stages and calculate the i Anchor load stiffness increment during the first stage of pressure stabilization Δk稳压锚杆Fi = k 稳压锚杆Fi - k 稳压锚杆Fi-1 Compare the deformation stiffness of the anchor rod in two adjacent stabilization stages and calculate the i Anchor deformation stiffness increment during the first stage of pressure stabilization Δk 稳压锚杆li = k 稳压锚杆li - k 稳压锚杆li-1 Compare the fitting goodness of the anchor load time history curves in two adjacent stabilization stages and calculate the i The fitting goodness increment of anchor load time history curve in the first stage of pressure stabilization D R 稳压锚杆Fi =R 稳压锚杆Fi -R 稳压锚杆Fi-1 Compare the fitting goodness of the anchor deformation time history curves in two adjacent stabilization stages and calculate the i The fitting goodness increment of anchor bolt deformation time history curve in the first stage of pressure stabilization D R 稳压锚杆li =R 稳压锚杆li -R 稳压锚杆li-1 Compare the maximum load of the anchor rod in two consecutive stabilization stages and calculate the i Maximum load increment of anchor bolt in the first stage of pressure stabilization ΔF 稳压锚杆imax = F 稳压锚杆imax - F 稳压锚杆i-1max Compare the maximum load of the anchor rod in two consecutive stabilization stages and calculate the i Maximum load increment of anchor bolt in the first stage of pressure stabilization Δl 稳压锚杆imax = l 稳压锚杆imax - l 稳压锚杆i-1max .

[0106] No. i Level loading stage (or i The change in the stability of the tunnel confining pressure and the increment of the deformation stiffness of the cylinder in the loading stage (or the pressure stabilization stage) , cylinder load-displacement curve fitting goodness increment D R 油缸Fi , Maximum displacement increment of the cylinder , Cylinder deformation stiffness increment Δk 稳压油缸li , displacement time history curve fitting goodness increment D R 稳压油缸li , Maximum displacement increment of the cylinder Δl 稳压油缸imax , portal bracket load stiffness increment Δk 加载支架Fi, portal bracket deformation stiffness increment D k 加载支架li , the fitting goodness increment of the portal support load time history curve D R 加载支架Fi , fitting goodness increment of deformation time history curve of portal bracket D R 加载支架li , Maximum load increment of portal bracket ΔF 加载支架imax , Maximum load increment of portal bracket Δl 加载支架imax , portal bracket load stiffness increment Δk 稳压支架Fi , portal bracket deformation stiffness increment Δk 稳压支架li , the fitting goodness increment of the portal support load time history curve in the pressure stabilization stage D R 稳压支架Fi , the fitting goodness increment of the deformation time history curve of the portal support in the stabilization stage D R 稳压支架li , Maximum load increment of portal bracket ΔF 稳压支架imax , Maximum load increment of portal bracket Δl 稳压支架imax , Anchor load stiffness increment Δk 加载锚杆Fi , Anchor deformation stiffness increment Δk 加载锚杆li , anchor load time history curve fitting goodness increment D R 加载锚杆Fi , anchor deformation time history curve fitting goodness increment D R 加载锚杆li , Anchor maximum load increment ΔF 加载锚杆imax , Anchor maximum load increment Δl 加载锚杆imax , Anchor load stiffness increment Δk 稳压锚杆Fi , Anchor deformation stiffness increment Δk 稳压锚杆li , anchor load time history curve fitting goodness increment D R 稳压锚杆Fi , anchor deformation time history curve fitting goodness increment D R 稳压锚杆li , Anchor maximum load increment ΔF 稳压锚杆imax , Anchor maximum load increment Δl 稳压锚杆imax Positive correlation.

[0107] In addition, different weights can be assigned to the data increments of the above-mentioned support cylinders, gantry supports, and anchors to quantitatively characterize the change in the stability of the tunnel confining pressure. Specifically, the change in the stability of the tunnel confining pressure can be quantitatively characterized by the following formula: , where Indicates the stability of the tunnel confining pressure, Indicates the data increments of the support cylinder, gantry support, and anchor rod. represents the number of increments, represents the weight of each increment, and .

[0108] In other embodiments of the method for evaluating the surrounding rock characteristics of a tunnel during the service of an engineering tunnel of the present invention, during the impact load loading stage of the dynamic experiment, the anchor / gantry support obtains the corresponding increments of two adjacent impact loads through the load peak values ​​of two adjacent impact loads, the final load after the impact, the maximum load growth rate, the minimum load growth rate, the average load growth rate, the impulse peak value, the final impulse after the impact, the maximum impulse growth rate, the minimum impulse growth rate, the average impulse growth rate, the deformation peak value, the final deformation after the impact, the maximum deformation growth rate, the minimum deformation growth rate, the average deformation growth rate, the deformation absorption energy peak value, the final deformation absorption energy after the impact, the maximum deformation absorption energy growth rate, the minimum deformation absorption energy growth rate, and the average deformation absorption energy growth rate, and the response of the anchor / gantry support to the impact is positively correlated with the corresponding increments of the two adjacent impact loads.

[0109] Specifically, taking the data increment of the anchor rod in the dynamic test impact load loading stage as an example (the data increment of the portal bracket in the dynamic test impact load loading stage is consistent with that of the anchor rod, and the parameter data analysis can be performed with reference to the anchor rod), the peak values ​​of the anchor rod load after two adjacent impacts are compared. F 锚杆jmax , calculate the j Peak increment of anchor load after the first impact ΔF 锚杆jmax = F 锚杆jmax - F 锚杆j-1max Comparison of the final load of the anchor after two consecutive impacts F 锚杆jfin , calculate the j Final load increment of anchor bolt after the first impact ΔF 锚杆jfin = F 锚杆jfin - F 锚杆j-1fin Comparison of the average growth rate of anchor load after two consecutive impacts v F锚杆jave , calculate the j Average increase in anchor load after impact ΔvF锚杆jave = v F锚杆jave - v F锚杆j-1ave Comparison of the maximum growth rate of anchor load after two consecutive impacts v F锚杆jmax , calculate the j The maximum increase in the anchor load after the first impact Δv F锚杆jmax = v F锚杆jmax - v F锚杆j-1max Comparison of the minimum growth rate of anchor load after two consecutive impacts v F锚杆jmin , calculate the j Minimum increase in anchor load after impact Δv F锚杆jmin = v F锚杆jmin - v F锚杆j-1min Comparison of the peak values ​​of anchor deformation after two consecutive impacts l 锚杆jmax , calculate the j Peak increment of anchor deformation after the first impact Δl 锚杆jmax = l 锚杆jmax - l 锚杆j-1max Comparison of the final deformation of the anchor after two consecutive impacts l 锚杆jfin , calculate the j Final deformation increment of anchor bolt after the first impact Δl 锚杆jfin = l 锚杆jfin - l 锚杆j-1fin Comparison of the average growth rate of anchor deformation after two consecutive impacts v l锚杆jave , calculate the j Average growth rate of anchor bolt deformation after impact Δv l锚杆jave = v l锚杆jave - v l锚杆j-1ave Comparison of the maximum growth rate of anchor deformation after two consecutive impacts v l锚杆jmax , calculate the j The maximum increase in the deformation speed of the anchor bolt after the impact Δv l锚杆jmax = v l锚杆jmax - v l锚杆j-1maxComparison of the minimum growth rate of anchor deformation after two consecutive impacts v l锚杆jmin , calculate the j Minimum growth rate increment of anchor bolt deformation after the first impact D v l锚杆jmin = v l锚杆jmin - v l锚杆j-1min Comparison of the peak value of the bolt impulse after two consecutive impacts I 锚杆jmax , calculate the j Peak increment of bolt impulse after the first impact I 锚杆jmax = I 锚杆jmax - I 锚杆j-1max Comparison of the final impulse of the anchor after two consecutive impacts I 锚杆jfin , calculate the j Final impulse increment of anchor bolt after the first impact I 锚杆jfin = I 锚杆jfin - I 锚杆j-1fin Comparison of the average growth rate of the bolt impulse after two consecutive impacts v I锚杆jave , calculate the j Average increase in impulse speed of anchor bolt after impact Δv I锚杆jave = v I锚杆jave - v I锚杆j-1ave Comparison of the maximum impulse growth rate of the anchor bolt after two consecutive impacts v I锚杆jmax , calculate the j The maximum increase in the impulse speed of the anchor bolt after the first impact Δv I锚杆jmax = v I锚杆jmax - v I锚杆j-1max Comparison of the minimum impulse growth rate of the bolt after two consecutive impacts v I锚杆jmin , calculate the j Minimum increase in impulse speed of anchor bolt after impact Δv I锚杆jmin = v I锚杆jmin - v I锚杆j-1min Comparison of the peak value of the bolt impulse after two consecutive impacts I 锚杆jmax , calculate the jPeak increment of bolt impulse after the first impact I 锚杆jmax = I 锚杆jmax - I 锚杆j-1max Comparison of the final impulse of the anchor after two consecutive impacts I 锚杆jfin , calculate the j Final impulse increment of anchor bolt after the first impact I 锚杆jfin = I 锚杆jfin - I 锚杆j-1fin Comparison of the average growth rate of the bolt impulse after two consecutive impacts v I锚杆jave , calculate the j Average increase in impulse speed of anchor bolt after impact Δv I锚杆jave = v I锚杆jave - v I锚杆j-1ave Comparison of the maximum impulse growth rate of the anchor bolt after two consecutive impacts v I锚杆jmax , calculate the j The maximum increase in the impulse speed of the anchor bolt after the first impact Δv I锚杆jmax = v I锚杆jmax - v I锚杆j-1max Comparison of the minimum impulse growth rate of the bolt after two consecutive impacts v I锚杆jmin , calculate the j Minimum increase in impulse speed of anchor bolt after impact Δv I锚杆jmin = v I锚杆jmin - v I锚杆j-1min Comparison of the peak energy of the anchor bolt after two consecutive impacts E 锚杆jmax , calculate the j Peak increment of anchor energy after the first impact DE 锚杆jmax = E 锚杆jmax - E 锚杆j-1max Comparison of the final energy of the anchor after two consecutive impacts E 锚杆jfin , calculate the j Final energy increment of the bolt after the first impact DE 锚杆jfin = E 锚杆jfin - E锚杆j-1fin Comparison of the average energy growth rate of the anchor bolt after two consecutive impacts v E锚杆jave , calculate the j Average increase in bolt energy after impact Δv E锚杆jave = v E锚杆jave - v E锚杆j-1ave Comparison of the maximum energy growth rate of the anchor bolt after two consecutive impacts v E锚杆jmax , calculate the j The maximum increase in bolt energy after the first impact Δv E锚杆jmax = v E锚杆jmax - v E锚杆j-1max Comparison of the minimum energy growth rate of the anchor bolt after two consecutive impacts v E锚杆jmin , calculate the j Minimum increase in bolt energy after impact D v E锚杆jmin = v E锚杆jmin - v E锚杆j-1min . No. j After the first impact, the impact response of the anchor bolt is ΔF 锚杆jmax , ΔF 锚杆jfin , D v F锚杆jave , Δv F锚杆jmax , Δv F锚杆jmin Positive correlation.

[0110] No. j After the first impact, the response of the anchor to the impact is Δl 锚杆jmax , Δl 锚杆jfin , Δv l锚杆jave , Δv l锚杆jmax , D v l锚杆jmin The response of the anchor to the impact is positively correlated with I 锚杆jmax , I 锚杆jfin , Δv I锚杆jave , Δv I锚杆jmax , Δv I锚杆jmin The response of the anchor to the impact is positively correlated with DE 锚杆jmax , DE 锚杆jfin , Δv E锚杆jave , Δv E锚杆jmax , Δv E锚杆jmin Positive correlation.

[0111] Assuming that m anchors are installed in a certain test, the standard deviation, variance and range of various mechanical response parameters of all anchors (or those arranged in the same position) can be calculated to evaluate the homogeneity and stability of the surrounding rock. The standard deviation, variance and range of various mechanical response parameters are negatively correlated with the homogeneity and stability of the surrounding rock. The various mechanical response parameters include load peak, final load after impact, maximum load growth rate, minimum load growth rate, average load growth rate, impulse peak, final impulse after impact, maximum impulse growth rate, minimum impulse growth rate, average impulse growth rate, deformation peak, final deformation after impact, maximum deformation growth rate, minimum deformation growth rate, average deformation growth rate, deformation absorption energy peak, final deformation absorption energy after impact, maximum deformation absorption energy growth rate, minimum deformation absorption energy growth rate, and average deformation absorption energy growth rate.

[0112] For all anchors, the standard deviation of a mechanical response parameter is , the variance of a mechanical response parameter is , the range of a mechanical response parameter is , where X Can be replaced by any mechanical response parameter, such as F 锚杆jmax 、F 锚杆jfin , v F锚杆jave , v F锚杆jmax , v F锚杆jmin wait, X ave is the mean value of m anchor rods corresponding to the mechanical response parameters, .

[0113] According to the location of anchor bolt installation, anchor bolts can be divided into two categories: top anchor bolts, the number of which is m 顶 ; Anchor rod, quantity is m 帮 .

[0114] For the top anchor, the standard deviation of a mechanical response parameter is , the variance of a mechanical response parameter is , the range of a mechanical response parameter is , where X Can be replaced by any mechanical response parameter, such as F 锚杆jmax 、F 锚杆jfin , v F锚杆jave , v F锚杆jmax , v F锚杆jmin wait, X ave m is the corresponding mechanical response parameter 顶 The mean value of the anchor rods, .

[0115] For the anchor rod, the standard deviation of a mechanical response parameter is , the variance of a mechanical response parameter is , the range of a mechanical response parameter is , where X Can be replaced by any mechanical response parameter, such as F 锚杆jmax 、F 锚杆jfin , v F锚杆jave , v F锚杆jmax , v F锚杆jmin wait, X ave m is the corresponding mechanical response parameter 帮 The mean value of the anchor rods, .

[0116] Similarly, the side anchor rods can be divided into left side anchor rods and right side anchor rods, the number of which is m 左帮 , m 右帮 .

[0117] For the left anchor, the standard deviation of a mechanical response parameter is , the variance of a mechanical response parameter is , the range of a mechanical response parameter is , where X Can be replaced by any mechanical response parameter, such as F 锚杆jmax 、F 锚杆jfin , v F锚杆jave , v F锚杆jmax , v F锚杆jmin wait, X ave m is the corresponding mechanical response parameter 左帮 The mean value of the anchor rods, .

[0118] For the right anchor, the standard deviation of a mechanical response parameter is , the variance of a mechanical response parameter is , the range of a mechanical response parameter is , where X Can be replaced by any mechanical response parameter, such as F 锚杆jmax 、F 锚杆jfin , v F锚杆jave , v F锚杆jmax , v F锚杆jmin wait, X ave m is the corresponding mechanical response parameter 右帮 The mean value of the anchor rods, .

[0119] The standard deviation, variance, and range of any mechanical parameter at any position are negatively correlated with the homogeneity of the surrounding rock at that position. Generally speaking, the more developed the internal cracks in the surrounding rock, the worse the homogeneity and stability, that is, the homogeneity of the surrounding rock is positively correlated with its stability. Therefore, the standard deviation, variance, and range of any mechanical parameter at any position are negatively correlated with the stability of the surrounding rock at that position.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating the surrounding rock characteristics of an engineering tunnel during its service period, characterized in that: include: S1. Making a physical model of tunnel surrounding rock, and applying an initial static load to the physical model of tunnel surrounding rock through a loading device; S2, excavating the tunnel surrounding rock physical model of step S1, drilling anchor holes in the excavated tunnel, using anchors and gantry supports to support the tunnel, and providing support cylinders for the gantry supports to perform cylinder support; S3. Set up monitoring devices to monitor the load and deformation displacement of the support cylinder, anchor rod and gantry support; S4. Use a loading device to apply static and dynamic loads to the tunnel surrounding rock physical model to conduct static and dynamic experiments; monitor the load changes and deformation displacement changes of anchor rods, gantry supports and support cylinders during static and dynamic experiments to evaluate the homogeneity and stability of the tunnel surrounding rock; In step S4, applying static load and dynamic load to the tunnel surrounding rock physical model by using a loading device includes: S41, maintaining the displacement constraint in the axial direction of the excavated roadway by the physical model of the surrounding rock of the roadway, applying loads to the two sides and the top plate of the excavated roadway, and increasing the applied load value from the initial static load to the ultimate static load at a constant loading rate; the initial static load ,in is the original rock stress of the tunnel at the project site, q is the mechanical similarity ratio; the ultimate static load ,in is the tunnel support pressure at the engineering site, q is the mechanical similarity ratio; S42, unloading the ultimate static load applied to the two sides and the top plate of the tunnel excavation physical model at a constant rate until the load is unloaded to the post-mining static load; the post-mining static load ,in is the measured pressure on the roof and two sides of the tunnel after mining at the working face at the engineering site, and q is the mechanical similarity ratio; S43, applying impact dynamic load to the physical model of the tunnel surrounding rock; Wherein, when conducting a static experiment on the physical model of the tunnel surrounding rock, step S41 and step S42 are repeated alternately; when conducting a dynamic experiment on the physical model of the tunnel surrounding rock, step S41, step S42 and step S43 are repeated alternately in sequence; In step S41, a gradient loading method is adopted in the process of increasing the applied load value from the initial static load to the ultimate static load at a constant loading rate, including a static load loading stage and a static load stabilization stage. In the static load loading stage, the applied load value increases from the initial static load value to the first intermediate static load value, or from one of the intermediate static load values ​​to the next intermediate static load value, at a constant loading rate; in the static load stabilization stage, the applied intermediate static load value does not increase, and the currently applied intermediate static load value is used for stabilization for a set time.

2. The method for evaluating the surrounding rock characteristics of an engineering tunnel during service according to claim 1, characterized in that: In step S4, monitoring the load changes and deformation displacement changes of the anchor rod, the gantry support and the support cylinder during the static test and the dynamic test includes: During the static load loading stage of the static experiment, monitor the anchor end deformation and anchor end load data, gantry support deformation and load data, support cylinder load and displacement data; During the static load stabilization stage of the static test, monitor the anchor end deformation and anchor end load data, gantry support deformation and load data, support cylinder load and displacement data; During the impact load loading stage of the dynamic experiment, the load and deformation data of the portal support and the anchor end are monitored, and the impulse and energy data are calculated.

3. The method for evaluating the surrounding rock characteristics of an engineering tunnel during service according to claim 2, characterized in that: In the static load loading stage of the static experiment, based on the load and displacement data of the support cylinder, the load-displacement curve of the support cylinder is drawn, and a linear function is used for linear fitting to obtain the load-displacement fitting line of the support cylinder. The stiffness of the tunnel surrounding rock physical model and the stability of the tunnel surrounding rock are positively correlated with the fitting slope of the load-displacement curve of the support cylinder. The degree of crack development in the tunnel surrounding rock physical model is negatively correlated with the fitting goodness of the load-displacement fitting line of the support cylinder, and the stability of the tunnel surrounding rock is positively correlated with the fitting goodness of the load-displacement fitting line of the support cylinder. In the static load stabilization stage of the static experiment, based on the displacement data of the support cylinder, the displacement time history curve of the support cylinder is drawn, and a linear function is used for linear fitting to obtain the displacement time history fitting line of the support cylinder. The stiffness of the tunnel surrounding rock physical model and the stability of the tunnel surrounding rock are positively correlated with the absolute value of the fitting slope of the displacement time history curve of the support cylinder. The degree of crack development in the tunnel surrounding rock physical model is negatively correlated with the fitting goodness of the displacement time history fitting line of the support cylinder. The stability of the tunnel surrounding rock is positively correlated with the fitting goodness of the displacement time history fitting line of the support cylinder. In the static load loading stage and the static load stabilization stage of the static experiment, the load time history curve and the deformation time history curve of the portal support / anchor are drawn based on the deformation and load data of the portal support / anchor, and linear fitting is performed using linear functions to obtain the load time history fitting line and the deformation time history fitting line of the portal support / anchor. The stiffness of the tunnel surrounding rock physical model and the stability of the tunnel surrounding rock are positively correlated with the fitting slopes of the load time history curve and the deformation time history curve of the portal support / anchor. The degree of crack development in the tunnel surrounding rock physical model is negatively correlated with the goodness of fit of the load time history fitting line or the deformation time history fitting line of the portal support / anchor. The stability of the tunnel surrounding rock is positively correlated with the goodness of fit of the load time history fitting line or the deformation time history fitting line of the portal support / anchor. In the dynamic experiment impact load loading stage, after one impact load, based on the load data of the anchor end / gantry support, the load time history curve of the anchor / gantry support is drawn to obtain the initial load value, load peak value and final load after impact of the anchor / gantry support, calculate the load growth rate of the anchor / gantry support at any time, draw the load growth rate time history curve of the anchor / gantry support, and obtain the maximum load growth rate, minimum load growth rate and average load growth rate of the anchor / gantry support. The response of the anchor / gantry support to the impact is positively correlated with the load peak value of the anchor / gantry support, the final load after impact, the maximum load growth rate, the minimum load growth rate and the average load growth rate of the anchor / gantry support. In the dynamic experiment impact load loading stage, after one impact load, based on the load data of the anchor rod end / gantry support, the impulse of the anchor rod end / gantry support is calculated, and the impulse time history curve of the anchor rod / gantry support is drawn to obtain the initial value of the impulse of the anchor rod / gantry support, the impulse peak value and the final impulse after the impact of the anchor rod / gantry support. The impulse growth rate of the anchor rod / gantry support at any time is calculated, and the impulse growth rate time history curve of the anchor rod / gantry support is drawn to obtain the maximum growth rate, minimum growth rate and average growth rate of the impulse of the anchor rod / gantry support. The response of the anchor rod / gantry support to the impact is positively correlated with the impulse peak value of the anchor rod / gantry support, the final impulse after the impact, the maximum impulse growth rate, the minimum impulse growth rate and the average impulse growth rate of the anchor rod / gantry support respectively; In the dynamic experiment impact load loading stage, after one impact load, based on the deformation data of the anchor end / portal support, the deformation time history curve of the anchor / portal support is drawn to obtain the initial deformation value, deformation peak value and final deformation after impact of the anchor / portal support, the deformation growth rate of the anchor / portal support at any time is calculated, and the deformation growth rate time history curve of the anchor / portal support is drawn to obtain the maximum growth rate, minimum growth rate and average growth rate of the deformation of the anchor / portal support. The response of the anchor / portal support to the impact is positively correlated with the deformation peak value of the anchor / portal support, the final deformation after impact, the maximum growth rate of deformation, the minimum growth rate of deformation and the average growth rate of deformation. In the dynamic experiment impact load loading stage, after one impact load, the deformation absorption energy of the anchor end / gantry is calculated based on the load data and deformation data of the anchor end / gantry, and the deformation absorption energy time history curve of the anchor / gantry is drawn to obtain the initial value of the deformation absorption energy of the anchor / gantry, the deformation absorption energy peak value and the final deformation absorption energy after impact, the deformation absorption energy growth rate of the anchor / gantry at any time is calculated, and the deformation absorption energy growth rate time history curve of the anchor / gantry is drawn to obtain the maximum growth rate, minimum growth rate and average growth rate of the deformation absorption energy of the anchor / gantry. The response of the anchor / gantry to the impact is positively correlated with the deformation absorption energy peak value of the anchor / gantry, the final deformation absorption energy after impact, the maximum growth rate of the deformation absorption energy, the minimum growth rate of the deformation absorption energy and the average growth rate of the deformation absorption energy.

4. The method for evaluating the surrounding rock characteristics of an engineering tunnel during service according to claim 3, characterized in that: The load-displacement fitting line of the support cylinder is obtained by linear fitting through the following formula 1: Formula 1; In the formula Indicates the load data of the support cylinder loading stage, represents the fitted slope of the load-displacement curve, Indicates the displacement data of the support cylinder during loading phase, represents the fitting constant; The displacement time history fitting line of the support cylinder is obtained by linear fitting through the following formula 2: Formula 2: In the formula Indicates the displacement data of the support cylinder during the pressure stabilization stage. represents the fitting slope of the displacement time history curve, Indicates the pressure stabilization time of the support oil cylinder during the pressure stabilization stage. represents the fitting constant; The load time history fitting line of the portal bracket is obtained by linear fitting through the following formula 3: Formula 3; In the formula Indicates the load data of the portal support, represents the fitting slope of the load-time curve, represents the loading time of the portal support, represents the fitting constant; The deformation time history fitting line of the portal bracket is obtained by linear fitting through the following formula 4: Formula 4; In the formula Indicates the deformation data of the portal bracket. represents the fitting slope of the deformation time history curve, represents the loading time of the portal support, represents the fitting constant; The load time history fitting line of the anchor bolt is obtained by linear fitting through the following formula 5: Formula 5; In the formula Indicates the load data at the end of the anchor rod, represents the fitting slope of the load-time curve, represents the loading time of the anchor, represents the fitting constant; The deformation time history fitting line of the anchor rod is obtained by linear fitting through the following formula 6: Formula 6; In the formula Indicates the deformation data of the anchor end. represents the fitting slope of the deformation time history curve, represents the loading time of the anchor, represents the fitting constant; The load growth rate of the anchor / gantry support at any time is calculated by the following formula 7: Formula 7; In the formula Indicates the load growth rate of the anchor / gantry support at any time, represents the load of the anchor / gantry support at time t+1 after the jth impact, represents the load of the anchor / gantry support at time t-1 after the jth impact, Represents the time difference between two data points; The deformation growth rate of the anchor rod / gantry support at any time is calculated by the following formula 8: Formula 8; In the formula Indicates the deformation growth rate of the anchor rod / gantry support at any time, represents the deformation of the anchor rod / gantry support at time t+1 after the jth impact, represents the deformation of the anchor rod / gantry support at time t-1 after the jth impact, Represents the time difference between two data points; After an impact load, the impulse of the anchor end / gantry support is calculated by the following formula 9: Formula 9; In the formula Indicates the impulse of the anchor end / gantry support, represents the load of the anchor / gantry support at time t+1 after the jth impact, represents the load of the anchor / gantry support at time t-1 after the jth impact, Represents the time difference between two data points; The impulse growth rate of the anchor / gantry support at any time is calculated by the following formula: Formula 10; In the formula Indicates the impulse growth rate of the anchor / gantry support at any time, represents the impulse of the anchor / gantry support at time t+1 after the jth impact, represents the impulse of the anchor / gantry support at time t-1 after the jth impact, Represents the time difference between two data points; After an impact load, the deformation absorption energy of the anchor end / gantry support is calculated by the following formula 11: Formula XI; In the formula Indicates the deformation absorption energy of the anchor end / gantry support, represents the load of the anchor / gantry support at time t+1 after the jth impact, represents the load of the anchor / gantry support at time t-1 after the jth impact, represents the deformation of the anchor rod / gantry support at time t+1 after the jth impact, It represents the deformation of the anchor rod / gantry support at time t-1 after the jth impact; The deformation absorption energy growth rate of the anchor rod / gantry support at any time is calculated by the following formula 12: Formula twelve; In the formula It indicates the growth rate of deformation absorption energy of anchor rod / gantry support at any time. represents the deformation absorption energy of the anchor rod / gantry support at time t+1 after the jth impact, represents the deformation absorption energy of the anchor rod / gantry support at time t-1 after the jth impact, Represents the time difference between two data points.

5. The method for evaluating the surrounding rock characteristics of an engineering tunnel during service period according to claim 3 or 4, characterized in that: For the support cylinder, in the static load loading stage of the static experiment, the load-displacement curve fitting slope increment, the load-displacement fitting line fitting goodness increment and the maximum displacement increment of the support cylinder are obtained through the load-displacement curve fitting slope of the support cylinder in two adjacent loading stages, the fitting goodness of the load-displacement fitting line and the maximum displacement; in the static load stabilization stage of the static experiment, the displacement time history curve fitting slope increment, the displacement time history fitting line fitting goodness increment and the maximum displacement increment of the support cylinder are obtained through the displacement time history curve fitting slope of the support cylinder in two adjacent stabilization stages, the fitting goodness of the displacement time history fitting line and the maximum displacement; For the portal bracket, the fitting slope of the load-history curve and the deformation-history curve of the portal bracket in two adjacent loading stages or pressure stabilization stages, the goodness of fit of the load-history fitting line and the deformation-history fitting line of the portal bracket, the maximum load of the portal bracket, and the maximum deformation of the portal bracket are obtained to obtain the fitting slope increment of the load-history curve and the deformation-history curve of the portal bracket, the goodness of fit increment of the load-history fitting line and the deformation-history fitting line of the portal bracket, the maximum load increment of the portal bracket, and the maximum deformation increment of the portal bracket; For the anchor rod, the fitting slope increment of the load-history curve and deformation-history curve of the anchor rod, the fitting goodness of the load-history fitting line or the deformation-history fitting line of the anchor rod in two adjacent loading stages or pressure stabilization stages, the fitting goodness of the load-history fitting line or the deformation-history fitting line of the anchor rod, the maximum load at the end of the anchor rod, and the maximum deformation at the end of the anchor rod are obtained; By assigning different weights to the data increments of the above-mentioned support cylinders, gantry supports and anchor rods, the change in the stability of the tunnel confining pressure can be quantitatively characterized.

6. The method for evaluating the surrounding rock characteristics of an engineering tunnel during service period according to claim 5, characterized in that: The stability of the tunnel confining pressure in the static load loading stage or the pressure stabilization stage of the static experiment is positively correlated with the data increments of the above-mentioned support cylinder, gantry support, and anchor rod, and the change in the tunnel confining pressure stability is quantitatively characterized by the following formula 13: Formula XIII; In the formula Indicates the stability of the tunnel confining pressure, Indicates the data increments of the support cylinder, gantry support, and anchor rod. represents the number of increments, represents the weight of each increment, and .

7. The method for evaluating the surrounding rock characteristics of an engineering tunnel during service period according to claim 3 or 4, characterized in that: During the impact load loading stage of the dynamic experiment, the corresponding increments of the two adjacent impact loads are obtained through the load peak value of the two adjacent impact loads, the final load after impact, the maximum load growth rate, the minimum load growth rate, the average load growth rate, the impulse peak value, the final impulse after impact, the maximum impulse growth rate, the minimum impulse growth rate, the average impulse growth rate, the deformation peak value, the final deformation after impact, the maximum deformation growth rate, the minimum deformation growth rate, the average deformation growth rate, the deformation absorption energy peak value, the final deformation absorption energy after impact, the maximum deformation absorption energy growth rate, the minimum deformation absorption energy growth rate, and the average deformation absorption energy growth rate. The response of the anchor / gantry to the impact is positively correlated with the corresponding increments of the two adjacent impact loads.

8. The method for evaluating the surrounding rock characteristics of an engineering tunnel during service period according to claim 3 or 4, characterized in that: For each mechanical response parameter of the anchor / gantry support during the dynamic test impact load loading stage, the homogeneity and stability of the surrounding rock are evaluated by calculating the standard deviation, variance and range. The standard deviation, variance and range of each mechanical response parameter are negatively correlated with the homogeneity and stability of the surrounding rock. The standard deviation of a mechanical response parameter is calculated by the following formula 14: Formula 14; In the formula represents the standard deviation, m represents the number of anchors / gantry supports, x represents the mechanical response parameter value, is the mean value of the mechanical response parameters corresponding to m anchors / gantry supports; The variance of a mechanical response parameter is calculated by the following formula: Formula 15; In the formula represents the variance, m represents the number of anchors / gantry supports, x represents the mechanical response parameter value, is the mean value of the mechanical response parameters corresponding to m anchors / gantry supports; The range of a certain mechanical response parameter is calculated by the following formula: Formula 16; In the formula Indicates extremely poor, is the maximum value of the mechanical response parameter corresponding to m anchors / gantry supports, is the minimum value of the mechanical response parameter corresponding to m anchors / gantry supports; The various mechanical response parameters include load peak, final load after impact, maximum load growth rate, minimum load growth rate, average load growth rate, impulse peak, final impulse after impact, maximum impulse growth rate, minimum impulse growth rate, average impulse growth rate, deformation peak, final deformation after impact, maximum deformation growth rate, minimum deformation growth rate, average deformation growth rate, deformation absorption energy peak, final deformation absorption energy after impact, maximum deformation absorption energy growth rate, minimum deformation absorption energy growth rate, and average deformation absorption energy growth rate.

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