Safety assessment methods, devices, electronic equipment and storage media for tunnels

Abstract

This application provides a method, apparatus, electronic device, and computer-readable storage medium for tunnel safety assessment. The method includes: constructing a three-dimensional numerical model of the tunnel; analyzing the acceleration of the tunnel's internal structure using frequency domain analysis based on the three-dimensional numerical model to obtain a frequency domain distribution curve of the structure after vibration under excited load; determining the vibration frequency of the tunnel's internal structure after vibration under excited load based on the frequency domain distribution curve; calculating the natural frequency of the tunnel's internal structure based on the three-dimensional numerical model; and conducting a safety assessment of the tunnel based on the vibration frequency and the natural frequency. This application enables effective structural safety assessment.

Description

TECHNICAL FIELD

[0001] The present application relates to tunnel engineering technology, and in particular to a tunnel safety evaluation method and device, an electronic device, and a storage medium. BACKGROUND

[0002] In recent years, large-diameter tunnels are increasingly widely used in the construction of urban underground projects. In order to improve the cross-section utilization rate of large-diameter tunnels, some complex treatments are performed on the structure of the tunnel, such as adopting single-hole double-line or even single-hole double-layer public and private structures for tunnel design. Existing safety evaluation during operation mostly takes tunnel diseases as carriers to evaluate the safety performance of the overall structure of the tunnel. SUMMARY

[0003] The embodiments of the present application provide a tunnel safety evaluation method and device, an electronic device, and a computer readable storage medium, which can effectively evaluate the safety of the structure.

[0004] The technical solutions of the embodiments of the present application are implemented as follows:

[0005] The embodiments of the present application provide a tunnel safety evaluation method, which comprises the following steps:

[0006] Constructing a three-dimensional numerical model of the tunnel;

[0007] Based on the three-dimensional numerical model, the acceleration of the internal structure of the tunnel is analyzed by a frequency domain analysis method to obtain a frequency domain distribution curve after the structure is vibrated by an excited load;

[0008] Based on the frequency domain distribution curve, a vibration frequency of the internal structure of the tunnel after being vibrated by the excited load is determined;

[0009] Based on the three-dimensional numerical model, the natural frequency of the internal structure of the tunnel is calculated;

[0010] According to the vibration frequency and the natural frequency, the safety of the tunnel is evaluated.

[0011] In the above scheme, based on the three-dimensional numerical model, the acceleration of the internal structure of the tunnel is analyzed by a frequency domain analysis method to obtain a frequency domain distribution curve after the structure is vibrated by an excited load, which comprises the following steps:

[0012] An acceleration time history curve at the wheel-rail contact position of the middle section is extracted from the three-dimensional numerical model;

[0013] Based on the acceleration time history curve, a frequency domain analysis of the acceleration time history is performed by fast Fourier transform to obtain the frequency domain distribution curve.

[0014] In the above scheme, based on the three-dimensional numerical model, the natural frequency of the internal structure of the tunnel is calculated, which comprises the following steps:

[0015] vibrating the three-dimensional numerical model by linear perturbation to obtain a plurality of mode shape results;

[0016] calculating the natural frequency of the internal structure of the tunnel based on the plurality of mode shape results.

[0017] In the above scheme, the safety evaluation of the tunnel according to the vibration frequency and the natural frequency comprises:

[0018] determining the frequency ratio of the vibration frequency and the natural frequency;

[0019] obtaining the relationship between the dynamic coefficient and the frequency ratio;

[0020] determining the corresponding dynamic coefficient based on the frequency ratio and the relationship between the dynamic coefficient and the frequency ratio;

[0021] performing safety evaluation of the tunnel based on the dynamic coefficient.

[0022] In the above scheme, the safety evaluation of the tunnel based on the dynamic coefficient comprises:

[0023] obtaining a dynamic coefficient threshold;

[0024] when the dynamic coefficient threshold is greater than or equal to the dynamic coefficient threshold, determining that the safety evaluation of the tunnel fails;

[0025] when the dynamic coefficient threshold is less than the dynamic coefficient threshold, determining that the safety evaluation of the tunnel passes.

[0026] In the above scheme, the three-dimensional numerical model comprises a geological model of the periphery of the tunnel, and the method further comprises:

[0027] determining a plurality of sections that do not meet the high-quality geological condition from the three-dimensional numerical model based on the geological model;

[0028] performing safety evaluation for each section of the plurality of sections respectively.

[0029] In the above scheme, the method further comprises:

[0030] based on the three-dimensional numerical model, checking the strength of the bolt at the top of the tunnel's mid-partition wall, and analyzing the dynamic response of the bolt at the top and bottom of the mid-partition wall under the action of train load.

[0031] The embodiment of the present application provides a safety evaluation device of a tunnel, comprising:

[0032] a construction module configured to construct a three-dimensional numerical model of the tunnel;

[0033] An acceleration analysis module is configured to analyze acceleration of the internal structure of the tunnel based on the three-dimensional numerical model by using a frequency domain analysis method, and obtain a frequency domain distribution curve of the internal structure of the tunnel after the internal structure of the tunnel is vibrated by an exciting load.

[0034] A vibration frequency determination module is configured to determine a vibration frequency of the internal structure of the tunnel after the internal structure of the tunnel is vibrated by the exciting load based on the frequency domain distribution curve.

[0035] An inherent frequency calculation module is configured to calculate an inherent frequency of the internal structure of the tunnel based on the three-dimensional numerical model.

[0036] A safety evaluation module is configured to perform safety evaluation on the tunnel according to the vibration frequency and the inherent frequency.

[0037] An electronic device is provided in an embodiment of the present application, and the electronic device comprises:

[0038] A memory is configured to store executable instructions.

[0039] A processor is configured to execute the executable instructions stored in the memory, and implement a safety evaluation method of a tunnel provided in an embodiment of the present application.

[0040] A computer readable storage medium is provided in an embodiment of the present application, and the computer readable storage medium stores executable instructions, and is configured to cause a processor to execute the safety evaluation method of the tunnel provided in an embodiment of the present application.

[0041] In an embodiment of the present application, a three-dimensional numerical model of a tunnel is constructed; acceleration of an internal structure of the tunnel is analyzed based on the three-dimensional numerical model by using a frequency domain analysis method, and a frequency domain distribution curve of the internal structure of the tunnel after the internal structure of the tunnel is vibrated by an exciting load is obtained; a vibration frequency of the internal structure of the tunnel after the internal structure of the tunnel is vibrated by the exciting load is determined based on the frequency domain distribution curve; an inherent frequency of the internal structure of the tunnel is calculated based on the three-dimensional numerical model; and safety evaluation is performed on the tunnel according to the vibration frequency and the inherent frequency. The safety evaluation method can effectively realize safety detection of the overall structure of the tunnel by three-dimensional modeling and related frequency analysis, and can realize safety evaluation of the tunnel based on the vibration frequency and the inherent frequency. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 FIG. 1 is an optional structural schematic diagram of an electronic device 100 provided in an embodiment of the present application;

[0043] Figure 2 FIG. 2 is an optional flow schematic diagram of a safety evaluation method of a tunnel provided in an embodiment of the present application;

[0044] Figure 3 FIG. 3 is an optional structural schematic diagram of a three-dimensional numerical model provided in an embodiment of the present application;

[0045] Figure 4 is one optional structural schematic view of a tunnel body structure provided by an embodiment of the present application

[0046] Figure 5A is one optional structural schematic view of a cross section of a three-dimensional numerical model provided by an embodiment of the present application

[0047] Figure 5B is one optional structural schematic view of a cross section of a three-dimensional numerical model provided by an embodiment of the present application

[0048] Figure 5C is one optional structural schematic view of a cross section of a three-dimensional numerical model provided by an embodiment of the present application

[0049] Figure 6 is one optional schematic view of the relationship between a power coefficient and a frequency ratio provided by an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the purposes, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings, and the described embodiments should not be regarded as limiting the present application, and all other embodiments obtained by those of ordinary skill in the art without making any creative labor fall within the scope of protection of the present application.

[0051] In the following description, "some embodiments" are described, which describe a subset of all possible embodiments, but it can be understood that "some embodiments" can be the same subset or different subset of all possible embodiments, and can be combined with each other without conflict.

[0052] In the following description, the terms "first\second\third" are only to distinguish similar objects, and do not represent a specific order of the objects, and it can be understood that "first\second\third" can be interchanged with a specific order or sequence as allowed, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application, and are not intended to limit the present application.

[0054] In recent years, large-diameter tunnels are increasingly used in the construction of urban underground projects. In order to improve the cross-sectional utilization rate of large-diameter tunnels, single-hole double-line tunnels or even single-hole double-layer tunnels are designed. For single-hole double-line tunnels, a mid-partition wall is often constructed in the middle of the tunnel to distinguish the driving direction for disaster prevention and evacuation. The connection between the top of the mid-partition wall and the tunnel lining is always an important part affecting the structural safety of the tunnel during operation. The "flexible" joint scheme for the top of the mid-partition wall is constantly emerging. In this design scheme, the gap between the mid-partition wall and the top π-shaped piece is filled after the segment is assembled, that is, the gap is not filled immediately after the segment is assembled, but is filled after the segment generates a certain displacement. The purpose of this is to prevent the top of the mid-partition wall from being directly compressed and crushed. However, the new design brings new safety evaluation problems. The design of the joint at the top of the mid-partition wall reduces the connection strength between the mid-partition wall and the surrounding structure, which is prone to safety problems under the action of train load, ultimately affecting the safety of train operation. The traditional safety evaluation method for tunnels during operation cannot meet the safety evaluation of this kind of tunnel structure, so a safety evaluation method for this kind of tunnel structure during operation needs to be proposed.

[0055] Based on this, the embodiments of the present application provide a tunnel safety evaluation method and device, electronic equipment and computer readable storage medium, which can effectively evaluate the safety of the structure.

[0056] First, the electronic equipment provided by the embodiments of the present application for implementing the tunnel safety evaluation method described above is described. Referring to Figure 1 , Figure 1 is an optional structural schematic diagram of the electronic equipment 100 provided by the embodiments of the present application. In actual application, the electronic equipment 100 can be implemented as a terminal or a server. The terminal can be a notebook computer, a tablet computer, a desktop computer, a smart phone, a dedicated message device, a portable game device, a smart speaker, a smart watch, etc., but is not limited thereto. The server can be a standalone physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server providing cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content distribution networks (CDN, Content Delivery Network) services, and basic cloud computing services such as big data and artificial intelligence platforms. Figure 1The illustrated electronic device 100 includes at least one processor 101, memory 105, at least one network interface 102, and a user interface 103. The various components of the electronic device 100 are coupled together by a bus system 104, which is capable of facilitating communication therebetween. It is understood that the bus system 104 is used in a generic sense and that the bus system 104 can include a combination of buses that can be implemented using any suitable bus structure including, for example, a data bus, a power bus, a control bus, and a state signal bus. For the sake of brevity, the various buses are collectively denoted as the bus system 104 in the following description. Figure 1

[0057] The processor 101 can be an integrated circuit chip that has processing capability, such as a general purpose processor, a Digital Signal Processor (DSP), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc.

[0058] The user interface 103 includes one or more output devices 1031 that enable presentation of media content, including one or more speakers and / or one or more visual display screens. The user interface 103 also includes one or more input devices 1032 that facilitate user input, such as a keyboard, a mouse, a microphone, a touch screen display, a camera, other input buttons and controls.

[0059] The memory 105 can be removable, non-removable, or a combination thereof. Exemplary hardware devices include solid-state memory, hard drives, optical drives, etc. The memory 105 optionally includes one or more storage devices physically located in proximity to the processor 101.

[0060] The memory 105 includes volatile memory or non-volatile memory, and can also include both volatile and non-volatile memory. Non-volatile memory can be read only memory (ROM), and volatile memory can be random access memory (RAM). The memory 105 described in the embodiments of the present application is intended to encompass any suitable type of memory.

[0061] In some embodiments, the memory 105 is capable of storing data to support various operations, examples of which include programs, modules, and data structures or a subset or superset thereof. In the embodiments of the present application, the memory 105 stores an operating system 1051, a network communication module 1052, a presentation module 1053, an input processing module 1054, and a security evaluation device of a tunnel 1055. Specifically,

[0062] ​The operating system 1051 includes system programs for processing various basic system services and performing hardware-related tasks, such as a framework layer, a core library layer, a driver layer, and the like, for implementing various basic services and processing hardware-based tasks;

[0063] The network communication module 1052 is configured to communicate with other computing devices via one or more (wired or wireless) network interfaces 102, exemplary network interfaces 102 including Bluetooth, Wireless Fidelity (WiFi), and Universal Serial Bus (USB), and the like;

[0064] The presentation module 1053 is configured to enable presentation of information via one or more output devices 1031 (e.g., a display screen, a speaker, and the like) associated with the user interface 103 (e.g., a user interface for operating a peripheral device and displaying content and information);

[0065] The input processing module 1054 is configured to detect and interpret one or more user inputs or interactions from one or more input devices 1032.

[0066] In some embodiments, the tunnel security evaluation apparatus provided by the embodiments of the present application can be implemented in a software manner, Figure 1 A tunnel security evaluation apparatus 1055 stored in the memory 105 is shown, which can be software in the form of programs and plug-ins, including the following software modules: a construction module 10551, an acceleration analysis module 10552, a vibration frequency determination module 10553, an inherent frequency calculation module 10554, and a security evaluation module 10555. These modules are logical, and thus can be combined or further split according to the functions implemented. The functions of each module will be described below.

[0067] In some embodiments, the tunnel security evaluation device provided by the embodiments of the present application can be implemented in a hardware manner. For example, the tunnel security evaluation device provided by the embodiments of the present application can be a processor in the form of a hardware decoding processor, which is programmed to execute the tunnel security evaluation method provided by the embodiments of the present application. For example, the processor in the form of a hardware decoding processor can be one or more application specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), or other electronic elements.

[0068] The tunnel security evaluation method provided by the embodiments of the present application will be described below in combination with exemplary applications and implementations of a terminal provided by the embodiments of the present application.

[0069] Referring to Figure 2 , Figure 2 is an optional flowchart of the tunnel security evaluation method provided by the embodiments of the present application, which will be described in combination with the steps shown in Figure 2 .

[0070] Step 201, constructing a three-dimensional numerical model of a tunnel;

[0071] Step 202, based on the three-dimensional numerical model, analyzing the acceleration of the internal structure of the tunnel by a frequency domain analysis method to obtain a frequency domain distribution curve after the structure is vibrated by an excited load;

[0072] Step 203, based on the frequency domain distribution curve, determining a vibration frequency of the internal structure of the tunnel after the structure is vibrated by the excited load;

[0073] Step 204, based on the three-dimensional numerical model, calculating a natural frequency of the internal structure of the tunnel;

[0074] Step 205, according to the vibration frequency and the natural frequency, performing a security evaluation on the tunnel.

[0075] In actual implementation, the terminal acquires survey geological information and design drawings, and establishes a fine three-dimensional numerical model of the tunnel based on the survey geological information and the design drawings. Here, the three-dimensional numerical model is constructed using a stratum structure method. The simulation of the external geology of the tunnel is performed according to information such as a geological survey report. The internal structure of the tunnel is simulated in a fine manner, and the main structures such as the joint piece, the partition wall, and the track slab are modeled finely according to the tunnel internal structure design drawings. The connection mode and interaction between the rings and between the internal structures can be further considered by a person skilled in the art according to the actual function of the tunnel.

[0076] Exemplarily, referring to Figure 3 , Figure 3 is an optional structural schematic diagram of the three-dimensional numerical model provided by the embodiments of the present application. Here, taking a municipal railway project as an example, a method for establishing a track bed-lining-soil system finite element model is introduced. Specifically, the model size is determined to be 110m x 70m x 50m in combination with the geological survey situation and the tunnel diameter. The three-dimensional numerical model includes a geological model 301 of the periphery of the tunnel and a tunnel body model 302 of the tunnel. Here, for the tunnel body structure, a single-hole double-line shield section is adopted, the shield diameter is 13.6m, the segment thickness is 0.55m, the ring width is 2m, and the segment adopts C60 concrete. The rings are connected by 34 M36 bolts, and a double-layer steel reinforcement is arranged inside the segment. The outer main reinforcement concrete protective layer has a thickness of 50mm, the inner main reinforcement concrete protective layer has a thickness of 40mm, the main reinforcement adopts HRB400E type steel reinforcement, and the average interval of the main reinforcement is 100mm. The tunnel bottom joint piece adopts C40 concrete. The tunnel partition wall is a reverse T-shaped structure, the bottom is connected to the joint piece by M36 bolts, the interval is 330mm, and the two sides are symmetrically placed, with a total of 10 in each section. The partition wall adopts C40 concrete. The top piece is connected to the lining by two rows of M20 bolts, the interval is 400mm, and the two sides are symmetrically placed, with a total of 8 in each section. The track slab adopts a solid element, and the material is C40 concrete. Referring to Figure 4 , Figure 4 is an optional structural schematic diagram of the tunnel body structure provided by the embodiments of the present application, and the tunnel body model includes top piece and lining connection bolts 401, partition wall 402, lining 403, joint piece 404, partition wall and joint piece connection bolts 405, track slab 406, and top piece 407.

[0077] In some embodiments, the three-dimensional numerical model includes a geological model of the periphery of the tunnel, and the method further includes: determining, based on the geological model, a plurality of sections that do not satisfy a high-quality geological condition from the three-dimensional numerical model; and respectively performing safety evaluation for each section in the plurality of sections.

[0078] In actual implementation, the terminal determines the tunnel operation period dynamic analysis working condition according to actual conditions. Specifically, the external load and internal member damage condition that the tunnel structure may be subjected to during the operation period are comprehensively analyzed, and different working condition analysis designs are performed in combination with different strata where the tunnel is located. The working conditions are divided into two types, namely, a regular working condition and a special working condition. The regular working condition is selected according to the shield tunnel design drawing, and the relevant section with a higher risk degree is selected for analysis according to the tunnel longitudinal section. The special working condition is simulated and evaluated in combination with the problems that may occur in the tunnel structure during train operation. In the embodiment of the present application, first, according to the regular working condition, the plurality of sections that do not meet the high-quality geological condition are determined from the three-dimensional numerical model based on the geological model, and the safety evaluation of the plurality of sections is performed, that is, the sections where the tunnel passes through the poor geological area are selected for analysis. The one-way and two-way driving working conditions are calculated respectively during the analysis. According to the calculation result, the most unfavorable condition is selected. For example, three sections are selected in the embodiment of the present application, as shown in Figures 5A-5C , Figures 5A-5C is a schematic structural diagram of a section of the three-dimensional numerical model provided by the embodiment of the present application. Secondly, the most unfavorable condition is taken as the reference, and the danger that may exist during the tunnel operation is considered. Here, the dangerous load conditions include train explosion load, train impact load and ground overload; the dangerous structure conditions include half failure of the top node and full failure of the top node. The above-mentioned possible dangers are combined through the actual operation of the tunnel during the operation period, and then the analysis and calculation are performed.

[0079] In the embodiment of the present application, the safety evaluation of the structure is further performed for different working condition designs. For the regular working condition detail structure response analysis, the vertical displacement, speed and acceleration values of different tunnel internal members need to be extracted, and the size of the dynamic response is determined whether it is out of limit in combination with the relevant specification. The tunnel safety state can be evaluated according to the acceleration, speed, displacement and structure resonance of the tunnel structure. The traditional dynamic response result evaluation is determined according to the current specification limit value, or through the way of refined numerical calculation. The conventional dynamic response limit value is shown in Table 1 and Table 2, wherein Table 1 is a safety allowable vibration speed table, and Table 2 is a tunnel displacement deformation monitoring early warning value, alarm value and control value table.

[0080] Table 1 Safety allowable vibration speed table

[0081] Serial No. Region Safety Allowable Vibration Velocity Commencement of Execution Time 1 Hong Kong 2.5 cm / s 1979 2 Beijing 2.5 cm / s 1969 3 Shanghai 2.5 cm / s 1993 4 Guangzhou 2.5 cm / s 1997 5 Tianjin 2.5 cm / s 2003

[0082] Table 2 Tunnel displacement deformation monitoring early warning value, alarm value and control value

[0083]

[0084]

[0085] In the embodiment of the present application, the terminal determines the safety evaluation result of the tunnel by evaluating the structural resonance of the tunnel. Specifically, in step 202, the terminal analyzes the acceleration of the internal structure of the tunnel based on the three-dimensional numerical model by a frequency domain analysis method to obtain a frequency domain distribution curve after the internal structure of the tunnel is vibrated by an excited load. In actual implementation, step 202 can be implemented by the following manner: extracting an acceleration time history curve at the wheel-rail contact of the middle section from the three-dimensional numerical model; performing frequency domain analysis on the acceleration time history based on the acceleration time history curve by fast Fourier transform to obtain the frequency domain distribution curve.

[0086] Then, the terminal obtains a vibration frequency f1 of the internal structure of the tunnel after the internal structure of the tunnel is vibrated by the excited load according to the frequency domain distribution based on the frequency domain distribution curve. Then, the terminal calculates the natural frequency of the internal structure of the tunnel based on the three-dimensional numerical model. Specifically, step 204 can be implemented by the following manner: performing self-vibration of the three-dimensional numerical model by a linear perturbation method to obtain a plurality of mode shape results; and calculating the natural frequency of the internal structure of the tunnel based on the plurality of mode shape results.

[0087] In actual implementation, the three-dimensional numerical model established in the first step is taken as an analysis object, the linear perturbation method is used to make the three-dimensional numerical model self-vibrate, the results of the first 20 modes are selected, and the high-order mode with the highest contribution in the dynamic response is used as a criterion to calculate the natural frequency f2 of the structure.

[0088] Then, the terminal performs safety evaluation on the tunnel according to the vibration frequency and the natural frequency. Specifically, step 205 can be implemented by the following manner: determining a frequency ratio of the vibration frequency to the natural frequency; obtaining a relationship between a dynamic coefficient and the frequency ratio; determining a corresponding dynamic coefficient based on the frequency ratio and the relationship between the dynamic coefficient and the frequency ratio; and performing safety evaluation on the tunnel based on the dynamic coefficient.

[0089] Specifically, the terminal calculates a frequency ratio β = f1 / f2 of the vibration frequency of the structure after the structure is loaded to the natural frequency of the structure by combining the structural dynamics method. The corresponding dynamic amplification coefficient D can be obtained by querying the relationship between the dynamic coefficient and the frequency ratio according to the value of the frequency ratio. Here, refer to Figure 6 , Figure 6 is an optional schematic diagram of the relationship between the dynamic coefficient and the frequency ratio provided by the embodiment of the present application. The damping ratio ξ is related to the material.

[0090] In some embodiments, the safety evaluation on the tunnel based on the dynamic coefficient comprises: obtaining a dynamic coefficient threshold; determining that the safety evaluation of the tunnel fails when the dynamic coefficient threshold is greater than or equal to the dynamic coefficient threshold; and determining that the safety evaluation of the tunnel passes when the dynamic coefficient threshold is less than the dynamic coefficient threshold.

[0091] In the embodiments of the present application, the power coefficient threshold value can be 3. When the frequency ratio β is located near 1 and ξ is less than 0.15, D≥3, then it is represented that the resonance has an influence on the tunnel body structure. According to the analysis result of the present example, the frequency ratio β is 50, and then the resonance phenomenon will not be generated.

[0092] In some embodiments, for special working conditions, the strength of the top bolt of the partition wall is also calculated. Specifically, the method further comprises: based on the three-dimensional numerical model, calculating the strength of the top bolt of the partition wall of the tunnel, and analyzing the dynamic response of the top and bottom bolts of the partition wall under the action of the train load.

[0093] In actual implementation, the cross section shown in FIG. 1 is taken as an example, the position of the cross section in front of the train position when the front and tail of the opposite train coincide is taken as the research object, and the dynamic response of the top and bottom bolts of the partition wall under the action of the train load is analyzed. Based on Table 3, the maximum internal force of the bolt at t=1.68s is taken. Figure 5A Table 3 Internal force of bolt when meeting train

[0094]

[0095] Position Shear Force / kN Axial Force / kN Top Bolts 2.16 15.33 Bottom Bolts 0.12 7.93

[0096] In actual implementation, the stress and strain conditions and fatigue strength of the key nodes are mainly checked. The key nodes include the top concrete of the partition wall, the internal force of the top bolt of the partition wall, etc., and the material strength formula is used to check whether the internal force of the structure is out of limit. The position of the cross section in front of the train position when the front and tail of the opposite train coincide is taken as the research object. The fatigue strength of the structure is checked according to the following formula, wherein the normal stress amplitude fatigue calculation is: △σ=σ max -0.7σ min . The shear stress amplitude fatigue calculation is: △τ=τ max -0.7τ min .

[0097] Wherein: △σ is the normal stress amplitude of the component or connecting part (N / mm 2 ), σ max is the maximum tensile stress value (taking the positive value) in the stress cycle of the calculation part (N / mm 2 ), σ min is the minimum tensile stress value (taking the positive value) or compressive stress (taking the negative value) in the stress cycle of the calculation part (N / mm 2 ), △τ is the shear stress amplitude of the component or connecting part (N / mm 2 ), τ max is the maximum shear stress value (N / mm 2 ) in the stress cycle of the calculation part, and τ min ​The minimum shear stress value (N / mm 2 ) in the stress cycle of the part is calculated t , γ e is a correction coefficient, which is 1.0, is the fatigue cutoff line of the normal stress amplitude, which is 37 MPa, is the fatigue cutoff line of the shear stress amplitude, which is 20 MPa.

[0098] In the calculation of the bearing capacity of the ordinary bolt in the tension direction, the following formula should be met:

[0099]

[0100] wherein, d t is the effective diameter of the bolt, f v is the design value of the tensile strength of the bolt. The design value of the shear bearing capacity should meet:

[0101]

[0102] wherein, n v is the number of shear planes, f max is the design value of the shear strength of the bolt.

[0103] According to the above formula, the tension and shear of the top bolt both meet the standard.

[0104] When the bolt is subjected to tension and shear at the same time, its bearing capacity should meet the following formula:

[0105]

[0106] According to the formula, the bearing capacity of the top bolt is:

[0107]

[0108] The result meets the bearing capacity condition.

[0109] Since the train load in the tunnel is a dynamic repeated load, the top node bolt is subjected to the repeated action of the dynamic load and will produce fatigue, so the fatigue strength of the top bolt needs to be checked. During the service life of the structure, the maximum and minimum normal stresses σ min of the top bolt subjected to one dynamic cycle are: σ max = 4N tmax / πd 2 = 48.82 MPa, σ min = 4N tmin / πd 2 = 15.51 MPa. Then the normal stress amplitude △σ of an 8.8 grade M20 bolt ordinary bolt at the calculation part is: △σ = σ max - 0.7 × σ min=37.96MPa, Therefore, during the structural service life, it can withstand 2×10 6 The fatigue reciprocating load. Based on a train departure interval of 30 minutes, the top bolts can be used normally for at least 114 years under full-load operation without rest every day.

[0110] During the structural service life, the maximum and minimum shear stress τ borne by the top bolt under one dynamic cycle. max and τ min For: τ max =4N vmax / πd 2 =8.49MPa, τ min =4N vmin / πd 2 =0.67MPa, then the shear stress amplitude of an ordinary bolt of grade 8.8 M20 is: The top bolts were tested for shear stress fatigue.

[0111] For the bottom bolts, since their type is superior to the top bolts and they bear less stress, their load-bearing capacity will not be checked here; only their fatigue life will be checked. The maximum and minimum normal stress σ borne by the bottom bolts under one dynamic cycle during the structure's service life will be calculated. max and σ min For: σ max =4N tmax / πd 2 =11.12MPa, σ min =4N tmin / πd 2 =10.06MPa. Therefore, the normal stress amplitude of an 8.8 grade M36 bolt (ordinary bolt) at the calculation location is: Δσ = σ max -0.7×σ min =4.178MPa, The bottom bolts were verified through normal stress fatigue strength calculation. The maximum and minimum shear stress τ under one dynamic cycle on the top bolts were determined during the structure's service life. max and τ min For: τ max =4N vmax / πd 2 =0.17MPa, τ min =4N vmin / πd 2 =0.13MPa. Therefore, the shear stress amplitude of an ordinary bolt (8.8 grade M20 bolt) at the calculated location is: The bottom bolts were verified through shear stress fatigue calculation.

[0112] The embodiment of the present application constructs a three-dimensional numerical model of the tunnel; based on the three-dimensional numerical model, analyzes the acceleration of the internal structure of the tunnel by a frequency domain analysis method, obtains a frequency domain distribution curve after the structure is vibrated by an excited load, determines a vibration frequency of the internal structure of the tunnel after the structure is vibrated by the excited load based on the frequency domain distribution curve, calculates the natural frequency of the internal structure of the tunnel based on the three-dimensional numerical model, and performs safety evaluation on the tunnel according to the vibration frequency and the natural frequency. The safety evaluation on the tunnel based on the vibration frequency and the natural frequency can effectively realize safety detection on the overall structure of the tunnel.

[0113] The following continues to describe an exemplary structure of the tunnel safety evaluation device 1055 provided by the embodiment of the present application as a software module. In some embodiments, as shown in FIG. 10, the software module stored in the tunnel safety evaluation device 1055 of the memory 105 can include: Figure 1

[0114] The construction module 10551 is configured to construct a three-dimensional numerical model of the tunnel.

[0115] The acceleration analysis module 10552 is configured to analyze the acceleration of the internal structure of the tunnel by a frequency domain analysis method based on the three-dimensional numerical model, and obtain a frequency domain distribution curve after the structure is vibrated by an excited load.

[0116] The vibration frequency determination module 10553 is configured to determine a vibration frequency of the internal structure of the tunnel after the structure is vibrated by the excited load based on the frequency domain distribution curve.

[0117] The natural frequency calculation module 10554 is configured to calculate the natural frequency of the internal structure of the tunnel based on the three-dimensional numerical model.

[0118] The safety evaluation module 10555 is configured to perform safety evaluation on the tunnel according to the vibration frequency and the natural frequency.

[0119] In some embodiments, the acceleration analysis module 10552 is further configured to extract an acceleration time history curve at a middle section wheel-rail contact from the three-dimensional numerical model, perform frequency domain analysis on the acceleration time history by fast Fourier transform based on the acceleration time history curve, and obtain the frequency domain distribution curve.

[0120] In some embodiments, the natural frequency calculation module 10554 is further configured to perform self-vibration on the three-dimensional numerical model by linear perturbation to obtain a plurality of mode shape results, and calculate the natural frequency of the internal structure of the tunnel based on the plurality of mode shape results.

[0121] ​In some embodiments, the safety evaluation module 10555 is further configured to determine a frequency ratio of the vibration frequency and the natural frequency; obtain a relationship between a dynamic coefficient and the frequency ratio; determine a corresponding dynamic coefficient based on the frequency ratio and the relationship between the dynamic coefficient and the frequency ratio; and perform safety evaluation on the tunnel based on the dynamic coefficient.

[0122] In some embodiments, the safety evaluation module 10555 is further configured to obtain a dynamic coefficient threshold; determine that the safety evaluation of the tunnel fails when the dynamic coefficient threshold is greater than or equal to the dynamic coefficient threshold; and determine that the safety evaluation of the tunnel passes when the dynamic coefficient threshold is less than the dynamic coefficient threshold.

[0123] In some embodiments, the three-dimensional numerical model includes a geological model of a tunnel periphery, and the device further includes an evaluation module configured to determine, based on the geological model, a plurality of sections that do not meet a high-quality geological condition from the three-dimensional numerical model; and perform safety evaluation on each section of the plurality of sections, respectively.

[0124] In some embodiments, the device further includes a dynamic response analysis module configured to perform checking calculation on bolt strength of a top of a mid-partition wall of a tunnel based on the three-dimensional numerical model, and analyze dynamic response of the bolt of the top and bottom of the mid-partition wall under train load.

[0125] It should be noted that the description of the device of the embodiments of the present application is similar to the description of the above method embodiments, has similar beneficial effects to the method embodiments, and thus is not described herein.

[0126] The embodiments of the present application provide a computer program product or a computer program, which includes computer instructions stored in a computer readable storage medium. A processor of a computer device reads the computer instructions from the computer readable storage medium, and the processor executes the computer instructions to enable the computer device to perform the safety evaluation method of the tunnel provided in the embodiments of the present application.

[0127] The embodiments of the present application provide a computer readable storage medium storing executable instructions, wherein the executable instructions, when executed by a processor, cause the processor to perform the method provided in the embodiments of the present application.

[0128] In some embodiments, the computer readable storage medium can be a memory such as FRAM, ROM, PROM, EPROM, EEPROM, flash memory, magnetic surface memory, optical disc, or CD-ROM; or various devices including one or any combination of the above memories.

[0129] In some embodiments, the executable instructions can be in the form of programs, software, modules, scripts, or code, written in any programming language, including compiled or interpreted languages, or declarative or procedural languages; and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0130] By way of example, the executable instructions can or can not correspond to a file in a file system, can be stored in a part of a file that holds other programs or data, e.g., one or more scripts stored in a markup language document, in a single file dedicated to the program in question, or in multiple coordinated files, e.g., files that store one or more modules, sub programs, or portions of code.

[0131] By way of example, the executable instructions can be stored on the one or more computer- readable storage media of a data carrier product, distributed to users of the computer system 100 over a network, or stored locally on the computer system 100.

[0132] In summary, through the embodiments of the present application, the safety evaluation of the structure can be effectively performed.

[0133] The above merely provides an example of the embodiments of the present application, but is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, and improvement within the spirit and scope of the present application shall be included in the protection scope of the present application.

Claims

1. A method for security assessment of a tunnel, characterized in that, The method comprises: constructing a three-dimensional numerical model of the tunnel; based on the three-dimensional numerical model, analyzing the acceleration of the internal structure of the tunnel by frequency domain analysis method to obtain the frequency domain distribution curve after the structure is vibrated by the excited load, comprising: extracting the acceleration time history curve of the wheel-rail contact at the middle section from the three-dimensional numerical model; based on the acceleration time history curve, performing frequency domain analysis on the acceleration time history by fast Fourier transform to obtain the frequency domain distribution curve; based on the frequency domain distribution curve, determining the vibration frequency of the internal structure of the tunnel after being vibrated by the excited load; based on the three-dimensional numerical model, calculating the natural frequency of the internal structure of the tunnel, comprising: self-vibrating the three-dimensional numerical model by linear perturbation to obtain multiple mode results; based on the multiple mode results, calculating the natural frequency of the internal structure of the tunnel; wherein, taking the three-dimensional numerical model as the analysis object, using the linear perturbation method to let it self-vibrate, selecting the results of the first 20 modes, and calculating the natural frequency of the structure according to the high-order mode with the highest contribution in the dynamic response; based on the vibration frequency and the natural frequency, performing safety evaluation on the tunnel, comprising: determining the frequency ratio of the vibration frequency and the natural frequency; obtaining the relationship between the dynamic coefficient and the frequency ratio; based on the frequency ratio and the relationship between the dynamic coefficient and the frequency ratio, determining the corresponding dynamic coefficient; based on the dynamic coefficient, performing safety evaluation on the tunnel; wherein, the safety evaluation on the tunnel based on the dynamic coefficient comprises: obtaining a dynamic coefficient threshold; when the dynamic coefficient is greater than or equal to the dynamic coefficient threshold, determining that the safety evaluation of the tunnel fails; when the dynamic coefficient is less than the dynamic coefficient threshold, determining that the safety evaluation of the tunnel passes.

2. The method of claim 1, wherein, The three-dimensional numerical model comprises a geological model of the tunnel periphery, and the method further comprises: based on the geological model, determining multiple sections that do not meet the high-quality geological conditions from the three-dimensional numerical model; performing safety evaluation on each section of the multiple sections respectively.

3. The method of claim 1, wherein, The method further comprises: based on the three-dimensional numerical model, checking the bolt strength of the top of the tunnel partition wall, and analyzing the dynamic response of the bolts at the top and bottom of the partition wall under the action of train load.

4. A security evaluation apparatus of a tunnel, characterized by comprising: The method comprises: a construction module for constructing a three-dimensional numerical model of the tunnel; an acceleration analysis module for analyzing the acceleration of the internal structure of the tunnel based on the three-dimensional numerical model by frequency domain analysis method to obtain the frequency domain distribution curve after the structure is vibrated by the excited load, and further for extracting the acceleration time history curve of the wheel-rail contact at the middle section from the three-dimensional numerical model; based on the acceleration time history curve, performing frequency domain analysis on the acceleration time history by fast Fourier transform to obtain the frequency domain distribution curve; a vibration frequency determination module for determining the vibration frequency of the internal structure of the tunnel after being vibrated by the excited load based on the frequency domain distribution curve; The inherent frequency calculation module is configured to calculate the inherent frequency of the internal structure of the tunnel based on the three-dimensional numerical model, and to obtain a plurality of vibration mode results by self-vibration of the three-dimensional numerical model in a linear perturbation manner; and to calculate the inherent frequency of the internal structure of the tunnel based on the plurality of vibration mode results. The inherent frequency calculation module is configured to calculate the inherent frequency of the internal structure of the tunnel based on the three-dimensional numerical model, and to obtain a plurality of vibration mode results by self-vibration of the three-dimensional numerical model in a linear perturbation manner; and to calculate the inherent frequency of the internal structure of the tunnel based on the plurality of vibration mode results. The safety evaluation module is configured to perform safety evaluation on the tunnel based on the vibration frequency and the inherent frequency, to determine a frequency ratio of the vibration frequency and the inherent frequency, to obtain a relationship between a dynamic coefficient and the frequency ratio, to determine a corresponding dynamic coefficient based on the frequency ratio and the relationship between the dynamic coefficient and the frequency ratio, and to perform safety evaluation on the tunnel based on the dynamic coefficient. The safety evaluation based on the dynamic coefficient includes obtaining a dynamic coefficient threshold value, determining that the safety evaluation of the tunnel fails when the dynamic coefficient is greater than or equal to the dynamic coefficient threshold value, and determining that the safety evaluation of the tunnel passes when the dynamic coefficient is less than the dynamic coefficient threshold value.

5. An electronic device, comprising: The method comprises: The memory is configured to store executable instructions. The processor is configured to execute the executable instructions stored in the memory to implement the method of any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, The executable instructions are stored in the memory and are configured to be executed by the processor to implement the method of any one of claims 1 to 3.

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