Safety Evaluation Method for the Construction of Tunnel Shotcrete-Arch Structure

Abstract

The present invention belongs to the field of tunnel engineering, and particularly relates to a construction safety evaluation method for a tunnel shotcrete-arch structure. The specific technical solution is as follows: according to the measured value of the surrounding rock pressure, a surrounding rock pressure-time function is obtained; according to the measured data of the shotcrete strength and elastic modulus, a shotcrete strength-age function and an elastic modulus-age function are obtained; based on the surrounding rock pressure-time function, the shotcrete strength-age function, and the elastic modulus-age function, the safety of the tunnel construction is evaluated by using the cross-section strength safety evaluation method in the failure stage. This method solves the defects of the current safety evaluation of the shotcrete-arch structure, takes into account the surrounding rock pressure and the time effect of the shotcrete, and realizes the safety evaluation of the whole construction process of the tunnel shotcrete-arch structure by the mechanized large-section method.

Description

Technical Field

[0001] The invention belongs to the field of tunnel engineering, and particularly relates to a construction safety evaluation method for a tunnel shotcrete-arch structure. Background Technique

[0002] The composite lining of a tunnel generally consists of primary support, waterproof isolation layer and secondary lining. Among them, the primary support, as the main load-bearing structure, is constructed in time after the tunnel excavation and bears most of the surrounding rock load. Therefore, as a form of tunnel primary support, it is necessary to evaluate the safety of the shotcrete-arch structure. At present, the commonly used safety analysis methods for primary support structures mainly include engineering analogy method, load-structure method, stratum-structure method, characteristic curve method, etc. Among them, the load-structure method has been widely used in tunnel engineering because its calculation theory is relatively easy to understand and the calculation means are relatively simple. The two key factors for evaluating the safety of primary support using the load-structure are the surrounding rock pressure and the calculation parameters of the primary support structure.

[0003] However, a large amount of measured data of surrounding rock pressure shows that the surrounding rock pressure will not be stable immediately after excavation, but gradually releases over time until it reaches the final stable state. Therefore, before the surrounding rock pressure reaches the stable state, if the surrounding rock pressure at the final stable state is still used to analyze the safety of the structure, certain errors will obviously occur. At the same time, after the shotcrete-arch structure is constructed, due to the certain time effect of shotcrete, it will not immediately reach the design strength and elastic modulus. Using the final design strength and elastic modulus values for safety evaluation will also produce certain errors. It can be seen that if the time effects of the surrounding rock pressure and shotcrete are not considered, the safety during the tunnel construction process cannot be evaluated.

[0004] Therefore, a construction safety evaluation method for a tunnel shotcrete-arch structure that simultaneously considers the time effects of surrounding rock pressure and shotcrete is needed. Summary of the Invention

[0005] To solve the above problems, the purpose of the present invention is to provide a construction safety evaluation method for a tunnel shotcrete-arch structure.

[0006] The technical solution adopted by the present invention to achieve the above invention purpose is: a tunnel construction safety evaluation method, obtaining a surrounding rock pressure-time function according to the measured value of the surrounding rock pressure; obtaining a shotcrete strength-age function and an elastic modulus-age function according to the measured data of the shotcrete strength and elastic modulus; and evaluating the tunnel construction safety based on the surrounding rock pressure-time function, the shotcrete strength-age function, and the elastic modulus-age function by using the cross-section strength safety evaluation method at the damage stage.

[0007] Preferably, it includes the following steps

[0008] Step 101: Obtain the measured values of the in-situ surrounding rock pressure under different tunnels and different surrounding rock grades, perform curve fitting on the measured values of the surrounding rock pressure, and obtain the surrounding rock pressure-time function;

[0009] Step 102: Obtain the measured values of the in-situ experimental strength and elastic modulus of shotcrete, perform curve fitting on the measured values of the strength and elastic modulus of shotcrete, and obtain the shotcrete strength-age function and elastic modulus-age function;

[0010] Step 103: Based on the surrounding rock pressure-time function, shotcrete strength-age function, and elastic modulus-age function, use the cross-section strength safety evaluation method in the damage stage to evaluate the safety of the entire construction process of the tunnel shotcrete-arch structure.

[0011] Preferably, the said Step 101 includes,

[0012] Step 1011: Obtain a large number of measured values of the in-situ surrounding rock pressure, classify the measured values of the surrounding rock pressure in different tunnels according to different surrounding rock grades, convert the measured surrounding rock pressure into vertical pressure and horizontal pressure, and obtain the envelope curves of the vertical pressure and horizontal pressure time history curves under each surrounding rock grade;

[0013] Step 1012: Based on the envelope curves of the vertical pressure and horizontal pressure time history curves, perform curve fitting on the vertical pressure and horizontal pressure of the measured values of the surrounding rock pressure, and obtain the variation laws of the vertical pressure and horizontal pressure with time.

[0014] Preferably, in the said Step 1012, multiple functions are used for data fitting, and the optimal fitting function is selected as the horizontal pressure-time function and vertical pressure-time function.

[0015] Preferably, the said Step 102 includes,

[0016] Step 1021: Conduct in-situ measurement experiments on the strength and elastic modulus of shotcrete to obtain the measured data of the strength and elastic modulus of shotcrete varying with age;

[0017] Step 1022: Based on the measured values of the in-situ strength and elastic modulus of shotcrete, perform curve fitting on the measured values obtained in this step, and obtain the variation laws of the strength and elastic modulus of shotcrete with age.

[0018] Preferably, in the said Step 1022, an exponential function is used to perform fitting analysis on the measured values of the in-situ strength and elastic modulus of shotcrete.

[0019] Preferably, the fitting function of the shotcrete strength:

[0020] σt = σ c，0 (1 - e -βt )

[0021] The fitting function of the elastic modulus of the shotcrete:

[0022] E t = E shot，0 (1 - e -αt )

[0023] E shot，σ and σ c，0 are respectively the ultimate elastic modulus and the uniaxial compressive strength value of the shotcrete; α and β are time constants.

[0024] Preferably: The step 103 includes,

[0025] Step 1031: Determine the surrounding rock level where the tunnel is located, calculate the theoretical ultimate value of the surrounding rock pressure at this surrounding rock level, and obtain the surrounding rock pressure values at different days based on the variation law of the surrounding rock pressure with time;

[0026] Step 1032: Determine the strength grade of the shotcrete, obtain the theoretical ultimate values of the strength and elastic modulus of the shotcrete at this strength grade, and obtain the strength and elastic modulus values of the shotcrete at different ages based on the variation law of the strength and elastic modulus of the shotcrete with age;

[0027] Step 1033: Establish a tunnel load - structure model, assign the surrounding rock pressure values at different days and the strength and elastic modulus values of the shotcrete at different ages to the load - structure model, and calculate the internal forces of the structure at different days after the shotcrete - arch structure is constructed;

[0028] Step 1034: Based on the internal forces of the shotcrete - arch structure obtained in step 1033, use the safety evaluation method of the cross - section strength at the failure stage to conduct a safety evaluation of the construction process of the shotcrete - arch structure.

[0029] Correspondingly: An electronic device, including:

[0030] One or more processors;

[0031] A storage device for storing one or more programs;

[0032] When the one or more programs are executed by the one or more processors, the one or more processors implement the tunnel construction safety evaluation method.

[0033] Correspondingly: A computer - readable medium, the readable medium stores a computer program, and when the computer program is executed by a processor, the tunnel construction safety evaluation method is implemented.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] Based on the measured values of the in-situ surrounding rock pressure, various functional forms are used to fit and analyze the data to obtain the variation law of the surrounding rock pressure with time; according to the measured data of the in-situ experimental strength and elastic modulus of shotcrete, the exponential function is used to fit and analyze the data to obtain the variation laws of the strength and elastic modulus of shotcrete with age; based on the variation law of the surrounding rock pressure with time and the variation laws of the strength and elastic modulus of shotcrete with age, the safety evaluation method of the cross-section strength in the damage stage is used to evaluate the safety of the whole construction process of the shotcrete-arch structure in the mechanized large-section tunnel method. After obtaining the variation law of the surrounding rock pressure with time and the variation laws of the strength and elastic modulus of shotcrete with age, the structural safety of each day after the construction of the shotcrete-arch structure can be evaluated, so as to optimize the design parameters. This method solves the defects of the current safety evaluation of the shotcrete-arch structure, takes into account the time effect of the surrounding rock pressure and shotcrete, and realizes the safety evaluation of the whole construction process of the shotcrete-arch structure in the mechanized large-section tunnel method. Description of the Drawings

[0036] Figure 1 is the flow chart of the construction safety evaluation method for the shotcrete-arch structure of the tunnel in the present invention;

[0037] Figure 2 is the schematic diagram of the variation law of the vertical component of the measured value of the surrounding rock pressure in the mechanized large-section tunnel method of the present invention with time;

[0038] Figure 3 is the schematic diagram of the variation law of the horizontal component of the measured value of the surrounding rock pressure in the mechanized large-section tunnel method of the present invention with time;

[0039] Figure 4 is the schematic diagram of the variation law of the strength of shotcrete in the mechanized large-section tunnel method of the present invention with age;

[0040] Figure 5 is the schematic diagram of the load-structure calculation model of the mechanized large-section tunnel method of the present invention;

[0041] Figure 6 is the schematic diagram of the structural axial force obtained by calculating the load-structure model of the mechanized large-section tunnel method of the present invention;

[0042] Figure 7 is the schematic diagram of the structural bending moment obtained by calculating the load-structure model of the mechanized large-section tunnel method of the present invention. Detailed Embodiments

[0043] The present invention will be described in detail and completely in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention and are only further descriptions of the invention. If not specifically specified, the technical means and terms used in the embodiments are the same as the conventional understanding of those skilled in the art.

[0044] The present invention discloses a construction safety evaluation method for a tunnel shotcrete-arch structure. The core idea is: according to the measured value of the surrounding rock pressure, obtain the surrounding rock pressure-time function P = P 0 A(t); according to the measured data of the shotcrete strength and elastic modulus, obtain the shotcrete strength-age function σ = σ 0 B(t) and the elastic modulus-age function E = E 0 C(t); based on the surrounding rock pressure-time function, the shotcrete strength-age function, and the elastic modulus-age function, use the cross-section strength safety evaluation method at the damage stage to evaluate the construction safety of the tunnel. Where p 0 、σ 0 、E 0 are the final measured values of the surrounding rock pressure, the shotcrete strength, and the shotcrete elastic modulus respectively. The values after the surrounding rock pressure, the shotcrete strength, and the shotcrete elastic modulus are stabilized are used as the final values. A(t), B(t), and C(t) are all functions that change with time.

[0045] Specifically, based on the measured value of the on-site surrounding rock pressure, various function forms are used to fit and analyze the data to obtain the variation law of the surrounding rock pressure with time growth; according to the measured data of the shotcrete strength and elastic modulus from on-site experiments, the exponential function is used to fit and analyze the data to obtain the variation laws of the shotcrete strength and elastic modulus with age; based on the variation law of the surrounding rock pressure with time growth and the variation laws of the shotcrete strength and elastic modulus with age, the cross-section strength safety evaluation method at the damage stage is used to evaluate the construction safety of the entire process of the tunnel shotcrete-arch structure by the mechanized large-section method.

[0046] As Figure 1 shown, a construction safety evaluation method for a tunnel shotcrete-arch structure includes the following steps:

[0047] Step 101: Collect a large amount of measured data of the on-site surrounding rock pressure under different tunnels and different surrounding rock grades, use various function forms to fit and analyze the measured data of the surrounding rock pressure, select the optimal fitting result, that is, the optimal fitting function, and obtain the variation law of the surrounding rock pressure with time growth. The function forms include multi-segment functions, polynomial functions, power functions, exponential functions, logarithmic functions, hyperbolic functions, etc.

[0048] Specifically, step 101 includes the following steps:

[0049] Step 1011: Collect the on-site measured values of the surrounding rock pressure under a large number of different tunnels and different surrounding rock grades. Classify the measured values of the surrounding rock pressure of different tunnels according to different surrounding rock grades, convert the measured surrounding rock pressure into vertical pressure and horizontal pressure, and organize and optimize to obtain the envelope curves of the vertical pressure and horizontal pressure time history curves under each surrounding rock grade respectively.

[0050] Step 1012: Based on the envelope curves of the vertical pressure and horizontal pressure time history curves, use various function forms to perform fitting analysis on the data, select the optimal fitting result, and respectively obtain the variation laws of the vertical pressure and horizontal pressure with time growth under different surrounding rock grades, as Figure 2 、 Figure 3 shown. It should be noted that the method of using various function forms for fitting and then selecting the optimal result is that, assuming that a multi-segment function, a power function, and an exponential function are used to fit the data, the optimal fitting function is finally selected from these three functions. It can be understood that the more fitting functions are selected, the closer the optimal function selected from them is to the variation law of the surrounding rock pressure with time.

[0051] Step 102: Conduct on-site test experiments on the strength and elastic modulus of shotcrete. According to the on-site measured data, use the exponential function to perform fitting analysis on the on-site measured data to obtain the variation laws of the strength and elastic modulus of shotcrete with age.

[0052] Here, a function form of the strength and elastic modulus of shotcrete with age is given. Among them, the exponential function form of the strength of shotcrete can be:

[0053] σ t =σ c，0 (1 - e -βt )

[0054] The exponential function form of the elastic modulus of shotcrete can be:

[0055] E t =E shot，0 (1 - e -αt )

[0056] In the formula: E shot，0 、σ c，0 are the final elastic modulus and uniaxial compressive strength value of shotcrete respectively; α and β are time constants, and α is approximately equal to β.

[0057] Specifically, the said Step 102 includes the following steps:

[0058] Step 1021: Conduct the test experiments on the compressive strength and elastic modulus of the shotcrete used in the on-site construction of the shotcrete-arch structure, and obtain the measured values of the compressive strength and elastic modulus of the shotcrete at different ages.

[0059] Step 1022: Based on the measured values of the compressive strength and elastic modulus of the shotcrete at different ages obtained on-site, use the exponential function to perform fitting analysis on the data, and obtain the variation laws of the compressive strength and elastic modulus of the shotcrete with age. As Figure 4 shown is the variation law of the compressive strength of the shotcrete with age.

[0060] Step 103: Based on the variation law of the surrounding rock pressure with time growth, as well as the variation laws of the strength and elastic modulus of the shotcrete with age, use the cross-section strength safety evaluation method at the damage stage to evaluate the construction process safety of the shotcrete-arch structure in the mechanized large-section tunnel method.

[0061] Specifically, the step 103 includes the following steps:

[0062] Step 1031: Determine the surrounding rock level where the tunnel is located. According to the tunnel load calculation method in the railway tunnel design code, calculate the theoretical final values of the vertical and horizontal surrounding rock pressures P 1 , respectively, at this surrounding rock level. Based on the variation law of the surrounding rock pressure with time growth, calculate the vertical and horizontal surrounding rock pressure values P = P 1 A(t) at different days after the construction of the shotcrete-arch structure.

[0063] Step 1032: Determine the strength grade of the shotcrete used. Query the theoretical final values of the strength and elastic modulus of the shotcrete with the corresponding strength grade through the railway tunnel design code, σ 1 , E 1 , respectively. Based on the obtained variation laws of the strength and elastic modulus of the shotcrete with age, calculate the strength σ = σ 1 B(t) and the elastic modulus value E = E 1 C(t) of the shotcrete at different ages.

[0064] Step 1033: Establish a tunnel load-structure model for the mechanized large-section tunnel method in professional modeling software. The professional modeling software can be ansys, midas, abaqus, flac3D, etc. As Figure 5 shown, for the tunnel load-structure model established using ansys software, assign the strength and elastic modulus values of the shotcrete at different days to the model, and apply the surrounding rock pressure for the corresponding days for calculation to obtain the structural internal forces at different days after the construction of the shotcrete-arch structure, as Figure 6 , Figure 7 shown.

[0065] Step 1034: Based on the calculation results of the load - structure model, respectively extract the internal forces of the shotcrete - arch structure at different days after its construction. According to the regulations of the railway tunnel design code, use the cross - section strength safety evaluation method at the failure stage to calculate the structural cross - section safety factors of the shotcrete - arch structure at different days after its construction. Compare with the safety factor values specified in the code to obtain the structural safety of the shotcrete - arch structure at different days after its construction, and realize the safety evaluation of the whole construction process of the shotcrete - arch structure.

[0066] During the tunnel construction process, the surrounding rock pressure, the strength and elastic modulus of shotcrete all have time effects. After obtaining the variation laws of the surrounding rock pressure with time growth and the strength and elastic modulus of shotcrete with age, the safety of the primary support structure can be evaluated for each day after the shotcrete - arch structure is constructed, so as to optimize the design parameters. This method solves the defects of the current safety evaluation of the shotcrete - arch structure, takes into account the time effects of the surrounding rock pressure and shotcrete at the same time, and realizes the safety evaluation of the whole construction process of the shotcrete - arch structure in the mechanized large - section tunnel method.

[0067] An electronic device, comprising: one or more processors; a storage device for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the tunnel construction safety evaluation method. The electronic devices in the embodiments of the present disclosure may include, but are not limited to, mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Tablet Computers), PMPs (Portable Multimedia Players), vehicle terminals (such as vehicle navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc.

[0068] A computer - readable medium stores a computer program, and when the computer program is executed by a processor, it implements the tunnel construction safety evaluation method. In particular, according to the embodiments of the present disclosure, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments of the present disclosure include a computer program product, which includes a computer program carried on a non - transient computer - readable medium, and the computer program contains program codes for executing the method shown in the flowchart.

[0069] It should be noted that the computer-readable medium of the present disclosure can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0070] In the present disclosure, a computer-readable storage medium can be any tangible medium that contains or stores a program, and this program can be used by or in conjunction with an instruction execution system, apparatus, or device. In the present disclosure, a computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, and this computer-readable signal medium can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0071] In some embodiments, the client and the server can communicate using any currently known or future-developed network protocol such as HTTP (HyperText Transfer Protocol), and can be interconnected with digital data communication in any form or medium (e.g., a communication network). Examples of communication networks include local area networks ("LAN"), wide area networks ("WAN"), the Internet (e.g., the Internet), and peer-to-peer networks (e.g., ad hoc peer-to-peer networks), as well as any currently known or future-developed networks.

[0072] The above computer-readable medium can be included in the above electronic device; or it can exist separately without being assembled into the electronic device.

[0073] The above computer-readable medium carries one or more programs which, when executed by the electronic device, cause the electronic device to: based on the measured values of the in-situ surrounding rock pressure, perform fitting analysis on the data using various functional forms to obtain the variation law of the surrounding rock pressure with time; according to the measured data of the in-situ experimental values of the shotcrete strength and elastic modulus, perform fitting analysis on the data using an exponential function to obtain the variation laws of the shotcrete strength and elastic modulus with age; based on the variation law of the surrounding rock pressure with time and the variation laws of the shotcrete strength and elastic modulus with age, use the sectional strength safety evaluation method at the failure stage to evaluate the construction process safety of the shotcrete-arch structure in a mechanized large-section tunnel.

[0074] Computer program code for performing the operations of the present disclosure may be written in one or more programming languages or combinations thereof. The programming languages include, but are not limited to, object-oriented programming languages such as Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0075] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code that contains one or more executable instructions for implementing the specified logical function. It should also be noted that, in some alternative implementations, the functions marked in the blocks may occur in a different order than marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and the combinations of blocks in the block diagram and / or flowchart, may be implemented by a dedicated hardware-based system for performing the specified functions or operations, or may be implemented by a combination of dedicated hardware and computer instructions.

[0076] The units involved in the embodiments of the present disclosure can be implemented in software or in hardware. In some cases, the name of a unit does not constitute a limitation on the unit itself.

[0077] The functions described above herein can be performed, at least in part, by one or more hardware logic components. By way of example, and without limitation, the types of hardware logic components that may be used include: Field Programmable Gate Arrays (FPGA), Application Specific Integrated Circuits (ASIC), Application Specific Standard Products (ASSP), System on a Chip (SOC), Complex Programmable Logic Devices (CPLD), and the like.

[0078] In the context of the present disclosure, a machine-readable medium may be a tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of a machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a Read-Only Memory (ROM), an Erasable Programmable Read-Only Memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0079] The above description is only of the preferred embodiments of the present disclosure and an illustration of the technical principles applied. Those skilled in the art should understand that the scope of the disclosure involved in the present disclosure is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosure concept. For example, a technical solution formed by mutually replacing the above features with technical features having similar functions (but not limited to) disclosed in the present disclosure.

[0080] In addition, although the operations are depicted in a particular order, this should not be construed as requiring that the operations be performed in the particular order shown or in sequential order. In certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of the present disclosure. Certain features described in the context of separate embodiments may also be implemented combinatorially in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented separately or in any suitable sub-combination in multiple embodiments.

[0081] Although the subject matter has been described in language specific to structural features and / or methodological logical acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. On the contrary, the specific features and acts described above are merely example forms for implementing the claims.

[0082] The embodiments described above are only for describing the implementation manners of the present invention, and do not limit the scope of the present invention. Based on the technical solutions of the present invention, all kinds of deformations, variations, modifications, and substitutions made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. Construction safety evaluation method for shotcrete-arch structure in tunnel, Characterized in that: According to the measured value of surrounding rock pressure, the surrounding rock pressure-time function is obtained; according to the measured data of shotcrete strength and elastic modulus, the shotcrete strength-age function and elastic modulus-age function are obtained; based on the surrounding rock pressure-time function, shotcrete strength-age function, and elastic modulus-age function, the safety of tunnel construction is evaluated by using the cross-section strength safety evaluation method in the failure stage; Including the following steps, Step 101: Obtain the measured values of on-site surrounding rock pressure under different tunnels and different surrounding rock grades, perform curve fitting on the measured values of surrounding rock pressure, and obtain the surrounding rock pressure-time function; Step 102: Obtain the measured values of on-site experimental shotcrete strength and elastic modulus, perform curve fitting on the measured values of shotcrete strength and elastic modulus, and obtain the shotcrete strength-age function and elastic modulus-age function; Step 103: Based on the surrounding rock pressure-time function, shotcrete strength-age function, and elastic modulus-age function, use the cross-section strength safety evaluation method in the failure stage to calculate the structural cross-section safety factors at different days after the construction of the shotcrete-arch structure respectively, compare with the specified safety factor value, obtain the structural safety at different days after the construction of the shotcrete-arch structure, and evaluate the safety of the whole construction process of the tunnel shotcrete-arch structure; The said Step 101 includes, Step 1011: Obtain a large number of measured values of on-site surrounding rock pressure, classify the measured values of surrounding rock pressure in different tunnels according to different surrounding rock grades, convert the measured surrounding rock pressure into vertical pressure and horizontal pressure, and obtain the envelope curves of vertical pressure and horizontal pressure time history curves under each surrounding rock grade; Step 1012: Based on the envelope curves of vertical pressure and horizontal pressure time history curves, perform curve fitting on the vertical pressure and horizontal pressure of the measured values of surrounding rock pressure, and obtain the variation law of vertical pressure and horizontal pressure with time.

2. The construction safety evaluation method for shotcrete-arch structure in tunnel according to claim 1, Characterized in that: In the said Step 1012, multiple functions are used for data fitting, and the optimal fitting function is selected as the horizontal pressure-time function and vertical pressure-time function.

3. The construction safety evaluation method for shotcrete-arch structure in tunnel according to claim 1, Characterized in that: The said Step 102 includes, Step 1021: Conduct on-site measurement experiments on shotcrete strength and elastic modulus to obtain the measured data of the variation of shotcrete strength and elastic modulus with age; Step 1022: Based on the measured values of on-site shotcrete strength and elastic modulus, perform curve fitting on the measured values obtained in this step to obtain the variation law of shotcrete strength and elastic modulus with age.

4. The construction safety evaluation method for shotcrete-arch structure in tunnel according to claim 3, Characterized in that: In the said Step 1022, the exponential function is used to fit and analyze the measured values of on-site shotcrete strength and elastic modulus.

5. The construction safety evaluation method for the tunnel shotcrete-arch structure according to claim 4, characterized in that: the fitting function of the shotcrete strength: σ t = σ c,0 (1 - e -βt ) the fitting function of the shotcrete elastic modulus: E t = E shot,0 (1 - e -αt ) E shot,0 and σ c,0 are the ultimate elastic modulus and uniaxial compressive strength values of shotcrete, respectively; α and β are time constants.

6. The construction safety evaluation method for the tunnel shotcrete-arch structure according to claim 1, characterized in that: step 103 includes, step 1031: Determine the surrounding rock level of the tunnel, calculate the theoretical final value of the surrounding rock pressure at this surrounding rock level, and obtain the surrounding rock pressure values at different days based on the variation law of the surrounding rock pressure with time; step 1032: Determine the shotcrete strength grade, obtain the theoretical final values of the shotcrete strength and elastic modulus at this strength grade, and obtain the shotcrete strength and elastic modulus values at different ages based on the variation law of the shotcrete strength and elastic modulus with age; step 1033: Establish a tunnel load-structure model, assign the surrounding rock pressure values at different days and the shotcrete strength and elastic modulus values at different ages to the load-structure model, and calculate the structural internal forces at different days after the shotcrete-arch structure is constructed; step 1034: Based on the internal forces of the shotcrete-arch structure obtained in step 1033, use the cross-section strength safety evaluation method in the failure stage to conduct a construction process safety evaluation of the shotcrete-arch structure.

7. An electronic device, characterized in that: it includes: one or more processors; a storage device for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the construction safety evaluation method for the tunnel shotcrete-arch structure as described in any one of claims 1-6.

8. A computer-readable medium storing a computer program, characterized in that: when the computer program is executed by a processor, it implements the construction safety evaluation method for the tunnel shotcrete-arch structure as described in any one of claims 1-6.

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