A method and system for determining the load of surrounding rock of a primary-secondary combined load-bearing arch

Abstract

This invention discloses a method and system for determining the surrounding rock load of a mother-and-child composite arch structure, belonging to the field of tunnel and underground engineering technology. The method includes: acquiring the geological, structural, and excavation parameters of the mother-and-child composite arch; calculating the baseline surrounding rock load of a single child arch; quantitatively calculating the mutual influence coefficient between child arches and the cross-lap reinforcement coefficient of anchor bolts using a pre-set structural column method; solving the comprehensive load of the child arches by combining distance attenuation characteristics; introducing a prestressed anchor cable unloading coefficient to quantify the unloading effect of active support, and correcting to obtain the final surrounding rock load; considering the longitudinal constraint effect at the tunnel face, outputting the peak load envelope diagram and the final long-term load distribution during the construction stage. This invention solves the problem of the inability to quantitatively and analytically calculate the surrounding rock load of ultra-large span mother-and-child composite arch structures, closely aligns with the construction sequence and structural mechanical characteristics, has high calculation accuracy, and can be programmed, providing a reliable basis for the support design of deep ultra-large span caverns.

Description

Technical Field

[0001] This invention relates to the field of tunnel and underground engineering science and technology, and in particular to a method and system for determining the surrounding rock load of a mother-daughter combined bearing arch applicable to ultra-large span caverns in deep underground spaces. Background Technology

[0002] With the deepening of energy, transportation, water conservancy and hydropower, and national defense infrastructure construction in my country, large underground storage facilities, ultra-long-span transportation tunnels, and deep mine chambers are increasingly common. Underground caverns are characterized by "large spans, high sidewalls, and high excavation rates," with some ultra-long-span caverns exceeding 80 meters in span. Under complex geological conditions such as high ground stress, traditional single-arch support structures and design theories are no longer sufficient to meet stability requirements. In engineering practice, an innovative mother-and-child composite arch support system has been proposed: using the sub-archs with critical stability sections as basic units, a single load-bearing arch is formed by systematic anchor bolts and shotcrete. Then, multiple sub-archs are continuously excavated according to a reasonable procedure, and the overall load-bearing mother arch is formed by cross-overlapping anchor bolts. This is supplemented by prestressed anchor cables for back tension reinforcement, ultimately achieving active control of ultra-long-span caverns.

[0003] However, there is still a lack of mature theoretical methods for calculating the surrounding rock load of the mother-daughter arch composite structure, resulting in the following significant technical shortcomings: 1. Traditional methods for calculating surrounding rock pressure, such as Protodyakonov's theory, Terzaghi's theory, and the deep-buried formulas in highway tunnel design specifications, all take the final formed single cavern as the calculation object. They can only give empirical estimates of the overall uniformly distributed load, which cannot reflect the non-uniformly distributed wave-like distribution characteristics of the load of each sub-arch during the step-by-step excavation of the mother-daughter combined arch. They also do not consider the load superposition effect of the excavated sub-arch on the excavated sub-arch. The calculation results deviate significantly from the actual mechanical behavior.

[0004] 2. Existing design methods do not consider the load-bearing contribution of active support. The combined arch effect formed by the cross-lapping of anchor bolts in the mother-daughter composite arch and the active anti-tension unloading effect of prestressed anchor cables will significantly change the distribution and magnitude of the surrounding rock load. However, traditional designs only treat the support as a passive load-bearing structure, ignoring the reduction effect of active support on the surrounding rock load. This leads to overly conservative design results, resulting in waste of engineering materials and increased costs.

[0005] 3. Lack of dynamic load calculation methods for the entire construction process. The longitudinal spatial constraint effect of the tunnel face has a significant impact on the load during the construction stage. Existing methods mostly only focus on the load in the final tunnel state, which cannot reflect the load evolution law of the entire process of step-by-step excavation, and it is difficult to guide the stability control of the surrounding rock and the optimization of support timing during the construction period.

[0006] 4. In engineering design, the determination of surrounding rock load relies heavily on numerical simulations and calculations. The design cycle is long, the parameter values ​​are highly dependent on the engineer's experience, and it is difficult to reuse and promote the technology across different projects. There is a lack of a systematic, analytical, and programmable system for calculating the surrounding rock load of the parent-child combined arch, which seriously restricts the engineering application and technology promotion of this new type of support structure.

[0007] Therefore, there is an urgent need for a method and system for determining the surrounding rock load of a parent-child composite bearing arch to solve the existing technical problems. Summary of the Invention

[0008] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a method and system for determining the surrounding rock load of a mother-daughter combined bearing arch.

[0009] In a first aspect, embodiments of the present invention provide a method for determining the surrounding rock load of a mother-daughter combined bearing arch, including: S100. Obtain the basic input parameters for determining the surrounding rock load of the parent-child composite arch; the basic input parameters include geological parameters, parent-child composite arch structural parameters, excavation parameters, and calculation control parameters; S200. Calculate the vertical reference surrounding rock load of a single sub-arch under isolated excavation conditions based on geological parameters and sub-arch geometric parameters; S300. Establish a numerical model for the excavation and support of the sub-arches. Set up high-rigidity elastic columns at the junction of adjacent sub-arches. Through step-by-step excavation and support construction, record the axial reaction force of the elastic columns under different working conditions. Calculate the mutual influence coefficient between sub-arches and the cross-lap reinforcement coefficient of anchor bolts based on the reaction force ratio. S400. Based on the reference load of a single sub-arch, combined with the mutual influence coefficients of all other sub-archs, span correction factor, distance attenuation coefficient, and anchor cross-lap reinforcement coefficient, the comprehensive vertical load of the sub-arch before applying prestressed anchor cables is calculated. S500. Calculate the equivalent unloading pressure of the prestressed anchor cable, introduce an unloading coefficient to quantify the reduction effect of the active counter-tension of the anchor cable on the load of the main arch, correct the comprehensive load of the sub-arch, and obtain the final surrounding rock load after the anchor cable is installed. S600. Based on the excavation and support status of each construction stage, calculate the final surrounding rock load of each sub-arch in the corresponding stage, extract the peak control load, and output the load envelope diagram and final cross-sectional load distribution of the construction stage.

[0010] Furthermore, in S100: the geological parameters include the unit weight of the surrounding rock γ, the angle of internal friction φ, the cohesion c, the uniaxial compressive strength Rc, the Protodyakonov strongness coefficient f, and the surrounding rock grade S; the structural parameters of the mother-daughter combined arch include the number of sub-arches n and the span of each sub-arch. , the height of each sub-arch Length of the cross-overlap zone of anchor bolts between sub-arches Parameters for the prestressed anchor cable arrangement scheme; the excavation parameters include the excavation sequence of each sub-arch and the excavation lag of each sub-arch relative to the first sub-arch. The calculated control parameters include the tunnel burial depth H and the safety factor of the support structure. .

[0011] Furthermore, in S200, Protodyakonov's formula is used to calculate the vertical reference surrounding rock load of a single sub-arch. The calculation formula is:

[0012] in, , which is the number of sub-arches, and f is the strength coefficient, which can be obtained from a table based on the hardness of the surrounding rock; For the span of the sub-arch, Φ is the arch height, f is the internal friction angle of the surrounding rock, f is the Protodyakonov hardness coefficient, and γ is the unit weight of the surrounding rock.

[0013] Furthermore, the specific methods of S300 include: S301. Establish a numerical model of excavation and support that includes the overlapping area of ​​adjacent sub-arches and anchor bolts, set the in-situ stress field and boundary conditions, and define the excavation and support steps according to the construction sequence. S302. A high-rigidity elastic column is set at the junction of the i-th sub-arch and the (i+1)-th sub-arch. The elastic modulus of the elastic column is a preset multiple of the elastic modulus of the surrounding rock. The lower end of the column is fixed and the upper end is hinged. It is used to sense the compressive stress at the junction. S303. Step-by-step loading and reaction force recording: The first step involves excavating only the i-th sub-arch and installing its own system of anchor bolts and shotcrete, without installing cross anchor bolts, and recording the axial pressure of the elastic column. ; The second step involves continuing to excavate the (i+1)th sub-arch and installing its own system of anchor bolts and shotcrete, without installing cross anchor bolts, and recording the axial pressure of the elastic column. ; The third step is to install the cross anchor bolts between the two sub-arches and record the axial pressure of the elastic column. ; S304. Calculate the mutual influence coefficient between sub-arches. The mutual influence coefficient between sub-arches is used to characterize the amplification effect of the later-excavated sub-arch on the load of the earlier-excavated sub-arch. The calculation formula is as follows:

[0014] S305. Calculate the reinforcement coefficient of anchor bolt cross-lap joints. The anchor bolt cross-lap reinforcement coefficient is used to characterize the reinforcement effect of cross anchor bolts on the load in the cross-lap area. The calculation formula is as follows: .

[0015] Furthermore, S300 also includes the calculation of the generalized influence coefficient for non-adjacent sub-arches. For the i-th sub-arch and the j-th sub-arch that are not directly adjacent, the generalized influence coefficient is calculated using an exponential decay function. The calculation formula is as follows:

[0016] in, The center distance between sub-arches i and j. , Let α be the span of the sub-arch, and α be the attenuation coefficient.

[0017] Furthermore, in S400, the calculation formula for the combined vertical load of the sub-arch is:

[0018] in, The vertical reference surrounding rock load for a single sub-arch is... This is the generalized influence coefficient. This is a span correction factor, reflecting the differences in the loosening range of sub-arches with different spans; The distance attenuation coefficient is calculated using the following formula:

[0019] in, Let be the center distance between sub-arches i and j. The distance attenuation coefficient for adjacent sub-arches is 1, and the distance attenuation coefficient for non-adjacent sub-arches is less than 1.

[0020] 1. Further, in S500, the prestressed anchor cable arrangement scheme includes centralized and distributed types. For the centralized arrangement, the total tension of the anchor cables in the junction area is... The area of ​​influence of the anchor cable is centered on the center of the junction area, with an effective radius of influence. , Anchorage length; unloading coefficient The calculation formula is:

[0021] In the formula, The area of ​​the anchor cable's influence zone. The average value of the combined loads of the two adjacent sub-arches is taken as the comprehensive load of the junction area. For a distributed arrangement, spacing is applied radially along the parent arch. The anchor cables are installed, and the tension of a single anchor cable is... The equivalent unloading pressure across the entire cross section is calculated by integration, and then the unloading coefficient is solved.

[0022] Furthermore, the unloading coefficient can also be precisely calculated directly using the preset structural column method, the specific method of which includes: Before and after applying anchor cable prestress in the numerical model, the axial pressure of the elastic column at the junction is recorded respectively. and The unloading coefficient is:

[0023] The revised final surrounding rock load is:

[0024] in, The total vertical load of the sub-arch.

[0025] Secondly, this invention also discloses a system for determining the surrounding rock load of a mother-daughter combined bearing arch, comprising: a parameter input module, a reference load calculation module, an influence coefficient calculation module, a comprehensive load calculation module, a load correction module, and a result output module; wherein: The parameter input module is used to obtain the basic input parameters for determining the surrounding rock load of the parent-child composite arch; the basic input parameters include geological parameters, parent-child composite arch structural parameters, excavation parameters, and calculation control parameters. The benchmark load calculation module is used to calculate the vertical benchmark surrounding rock load of a single sub-arch in isolated excavation state based on geological parameters and sub-arch geometric parameters. The influence coefficient calculation module is used to establish a numerical model of sub-arch excavation and support. High-rigidity elastic columns are set at the junction of adjacent sub-arches. Through step-by-step excavation and support construction, the axial reaction force of the elastic columns under different working conditions is recorded. Based on the reaction force ratio, the mutual influence coefficient between sub-arches and the cross-lap joint reinforcement coefficient of anchor bolts are calculated. The comprehensive load calculation module is used to calculate the comprehensive vertical load of the sub-arch before the application of prestressed anchor cables, based on the reference load of a single sub-arch and combined with the mutual influence coefficients of all other sub-archs, span correction factor, distance attenuation coefficient, and anchor cross-lap reinforcement coefficient. The load correction module is used to calculate the equivalent unloading pressure of the prestressed anchor cable, introduce an unloading coefficient to quantify the reduction effect of the active counter-tension of the anchor cable on the load of the main arch, correct the comprehensive load of the sub-arch, and obtain the final surrounding rock load after the anchor cable is installed. The results output module is used to calculate the final surrounding rock load of each sub-arch in the corresponding stage based on the excavation and support status of each construction stage, extract the peak control load, and output the load envelope diagram and final cross-sectional load distribution of the construction stage.

[0026] Thirdly, the present invention also discloses an electronic device, comprising: One or more processors; Memory, used to store 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 method.

[0027] This invention discloses a method and system for determining the surrounding rock load of a mother-and-child composite arch structure, belonging to the field of tunnel and underground engineering technology. The method includes: acquiring the geological, structural, and excavation parameters of the mother-and-child composite arch; calculating the baseline surrounding rock load of a single child arch; quantitatively calculating the mutual influence coefficient between child arches and the cross-lap reinforcement coefficient of anchor bolts using a pre-set structural column method; solving the comprehensive load of the child arches by combining distance attenuation characteristics; introducing a prestressed anchor cable unloading coefficient to quantify the unloading effect of active support, and correcting to obtain the final surrounding rock load; considering the longitudinal constraint effect at the tunnel face, outputting the peak load envelope diagram and the final long-term load distribution during the construction stage. This invention solves the problem of the inability to quantitatively and analytically calculate the surrounding rock load of ultra-large span mother-and-child composite arch structures, closely aligns with the construction sequence and structural mechanical characteristics, has high calculation accuracy, and can be programmed, providing a reliable basis for the support design of deep ultra-large span caverns.

[0028] Compared with the prior art, the present invention has the following beneficial effects: 1. The method and system for determining the surrounding rock load of the mother-and-child composite arch proposed in this invention establishes for the first time a surrounding rock load calculation system adapted to the staged excavation characteristics of the mother-and-child composite arch, breaking through the limitation of traditional methods that can only calculate the uniformly distributed load of a single final cavern. Through the quantitative calculation of the mutual influence coefficient between sub-arches and the reinforcement coefficient of the cross-lap joint of anchor bolts, the superposition effect of loads in the staged excavation of multiple sub-arches and the load concentration characteristics in the junction area are accurately reflected. The load distribution exhibits a wave-shaped characteristic consistent with the actual mechanical behavior, and the calculation accuracy is significantly improved compared with traditional empirical methods.

[0029] 2. This invention innovatively introduces a prestressed anchor cable unloading coefficient, quantifying the reduction effect of active support on the surrounding rock load, breaking the traditional design limitation that "support only passively bears the load." By accurately calculating the unloading effect of anchor cable counter-tension through the pre-set structural column method or analytical formula, it achieves coordinated design of active support and surrounding rock load, avoiding overly conservative design, effectively optimizing lining thickness and anchor cable usage, and reducing engineering construction costs.

[0030] 3. The pre-set structural column method proposed in this invention transforms the complex three-dimensional stress redistribution effect into quantitatively calculable dimensionless coefficients by setting high-stiffness elastic columns at the junctions to retrieve mechanical parameters. These coefficients have clear physical meaning and a standardized calculation process. Furthermore, by combining the exponential decay function with the generalized influence calculation of non-adjacent sub-arches, a complete influence coefficient matrix is ​​formed, balancing calculation accuracy with engineering practicality. After parameter calibration, it can be quickly extended to similar projects.

[0031] 4. The method of this invention has clear logic and standardized steps. All parameters have explicit calculation bases and can be fully implemented programmatically. It is easy to embed into existing underground engineering CAD design software or numerical simulation platforms. By inputting geometric, geological, and support parameters, the load envelope curve of the entire construction process can be generated with one click, eliminating the need for extensive repeated numerical simulations and calculations, significantly shortening the design cycle and improving design efficiency. It also supports iterative optimization functions, automatically matching support parameters with safety factor requirements, making it highly applicable to various engineering projects.

[0032] 5. This invention can also incorporate the longitudinal spatial constraint effect of the tunnel face to achieve accurate calculation of dynamic loads during the construction phase. It can fully reflect the load evolution law from the excavation of a single sub-arch to the formation of the main arch, providing a scientific theoretical basis for the control of surrounding rock stability, optimization of support timing, and adjustment of construction procedures during the construction period. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the sub-arch assembly forming a mother arch according to an embodiment of the present invention; Figure 2 A flowchart illustrating a method for determining the surrounding rock load of a mother-daughter combined bearing arch according to an embodiment of the present invention; Figure 3 This is a structural block diagram of a system for determining the surrounding rock load of a parent-child combined bearing arch, provided in an embodiment of the present invention. Figure 4 This is a structural block diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solutions of the present invention, exemplary embodiments of the present invention are described below in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0035] Where there is no conflict, the various embodiments of the present invention and the features thereof may be combined with each other.

[0036] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0037] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded. Terms such as “connected” or “linked” are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect.

[0038] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art and the invention, and will not be interpreted as having an idealized or overly formal meaning unless expressly so defined herein.

[0039] In the technical solution of this invention, the collection, storage, use, processing, transmission, provision, and disclosure of user personal information all comply with relevant laws and regulations and do not violate public order and good morals. The use of user data in this technical solution follows relevant national laws and regulations (e.g., the "Information Security Technology - Personal Information Security Specification"). For example: appropriate measures are taken for personal information access control; restrictions are imposed on the display of personal information; the purpose of using personal information does not exceed the scope of direct or reasonable association; and explicit identity targeting is eliminated when using personal information to avoid precisely locating a specific individual.

[0040] Existing technology proposes a design method for deep ultra-large span caverns that combines multiple sub-arches (critically stable caverns) to form a main arch (ultra-large span cavern). Using the critically stable cavern cross-section as a benchmark, additional system anchors and shotcrete are added to form load-bearing sub-arches; simultaneously, a reasonable excavation sequence (such as...) is followed. Figure 1 (Illustrated by numbers 1, 2, 3, and 4) Multiple continuous sub-arches are combined to form a "composite mega-arch" composed of a system of anchor bolts, serving as the load-bearing main arch for the ultra-large span cavern (as shown in the shaded area in the figure). Finally, prestressed anchor cables act as virtual rock columns to counter-tension the main arch, reducing the stress in the tension zone of the main arch and fully utilizing the mechanical advantages of the surrounding rock composite load-bearing arch under compression, ultimately forming a cavern structure that meets the target large span cavern type.

[0041] This structure transforms the traditional passive arch into an active arch that bears the load as a whole. The passive arch and the active arch work together to control the deformation of the surrounding rock and the risk of structural instability. Although the above technology provides the structural design and construction procedures for the mother-daughter composite arch, it lacks a quantitative and analytically calculable method for determining the surrounding rock pressure load, which is not convenient for carrying out support design work.

[0042] To address at least one of the technical problems existing in the aforementioned related technologies, the present invention provides a method and system for determining the surrounding rock load of a mother-daughter combined bearing arch.

[0043] This embodiment discloses a method for determining the surrounding rock load of a mother-daughter combined bearing arch, such as... Figure 1 ,include: S100. Obtain the basic input parameters for determining the surrounding rock load of the parent-child composite arch; the basic input parameters include geological parameters, parent-child composite arch structural parameters, excavation parameters, and calculation control parameters; In this embodiment, the geological parameters include the unit weight of the surrounding rock γ, the angle of internal friction φ, the cohesion c, the uniaxial compressive strength Rc, the Protodyakonov strongness coefficient f, and the surrounding rock grade S; the structural parameters of the mother-daughter combined arch include the number of sub-arches n and the span of each sub-arch. , the height of each sub-arch Length of the cross-overlap zone of anchor bolts between sub-arches Parameters for the prestressed anchor cable arrangement scheme; the excavation parameters include the excavation sequence of each sub-arch and the excavation lag of each sub-arch relative to the first sub-arch. The calculated control parameters include the tunnel burial depth H and the safety factor of the support structure. .

[0044] Specifically, the basic input parameters include: (1) Geological parameters (from the geological survey report): Commonly used rock mass physical and mechanical parameters include the unit weight of the surrounding rock γ (kN / m³), the internal friction angle φ (°), the cohesion c (kPa, used as an alternative formula), the uniaxial compressive strength of the rock Rc (MPa), the Protodyakonov coefficient f=0.1Rc (dimensionless), and the surrounding rock grade S (Ⅰ~Ⅵ).

[0045] (2) The parameters of the mother-daughter combined arch structure are as follows: Number of sub-arches n; Span of each sub-arch (m), ; Each son's arch is high (m) (For city gate arches, this refers to the height of the arch crown, which is the height of the straight wall section plus the arch rise). Length of the cross-over joint area of ​​anchor bolts between sub-arches (m); Prestressed anchor cable arrangement scheme (centralized or distributed): Centralized: Anchor cable tension at each junction area (kN), anchorage length (m); Distributed: Anchor cable radial spacing along the main arch Single tensile force Anchorage length (m).

[0046] (3) The excavation parameters are as follows: Excavation sequence of each sub-arch (determined according to the design, excavated in sequence according to the numbering); The excavation progress of each sub-arch lags behind that of the first sub-arch. (m) (For example, sub-arch 1 is excavated first, sub-arch 2 is 10m behind, and so on).

[0047] (4) The control parameters are calculated as follows: The burial depth of the cavern H (m) (this method is for deep burial); Safety factor (For anchor cable design, refer to the specifications or provided by the design team).

[0048] S200. Based on the geological parameters and the geometric parameters of the sub-arch, calculate the vertical reference surrounding rock load of a single sub-arch under isolated excavation conditions; in S200 of this embodiment, Protodyakonov's formula is used to calculate the vertical reference surrounding rock load of a single sub-arch. The calculation formula is:

[0049] in, , which is the number of sub-arches, and f is the strength coefficient, which can be obtained from a table based on the hardness of the surrounding rock; For the span of the sub-arch, Φ is the arch height, f is the internal friction angle of the surrounding rock, f is the Protodyakonov hardness coefficient, and γ is the unit weight of the surrounding rock.

[0050] Specifically, based on geological parameters (γ, φ, c, surrounding rock grade) and the geometric parameters of the sub-arch (span b_i, rise h_i), the vertical surrounding rock pressure of a single sub-arch in isolated excavation is calculated using Protodyakonov's formula or the deep-buried formula from the highway tunnel design specifications. .

[0051] ( (That is, the number of sub-arches) Where f is the firmness coefficient, which can be obtained from a table based on the hardness of the surrounding rock.

[0052] In the formula: —Span of the sub-arch; —Sub-arch rise (or sidewall height + rise, depending on the cross-sectional shape); φ—Internal friction angle of the surrounding rock (°); f—Protodextrin's strength coefficient, f=0.1Rc (Rc is the uniaxial compressive strength of rock, MPa); γ—Unit weight of surrounding rock (kN / m³).

[0053] S300. Establish a numerical model for the excavation and support of the sub-arches. Set up high-rigidity elastic columns at the junction of adjacent sub-arches. Through step-by-step excavation and support construction, record the axial reaction force of the elastic columns under different working conditions. Calculate the mutual influence coefficient between sub-arches and the cross-lap reinforcement coefficient of anchor bolts based on the reaction force ratio. The specific method in S300 of this embodiment includes: S301. Establish a numerical model of excavation and support that includes the overlapping area of ​​adjacent sub-arches and anchor bolts, set the in-situ stress field and boundary conditions, and define the excavation and support steps according to the construction sequence. S302. A high-rigidity elastic column is set at the junction of the i-th sub-arch and the (i+1)-th sub-arch. The elastic modulus of the elastic column is a preset multiple of the elastic modulus of the surrounding rock. The lower end of the column is fixed and the upper end is hinged. It is used to sense the compressive stress at the junction. S303. Step-by-step loading and reaction force recording: The first step involves excavating only the i-th sub-arch and installing its own system of anchor bolts and shotcrete, without installing cross anchor bolts, and recording the axial pressure of the elastic column. ; The second step involves continuing to excavate the (i+1)th sub-arch and installing its own system of anchor bolts and shotcrete, without installing cross anchor bolts, and recording the axial pressure of the elastic column. ; The third step is to install the cross anchor bolts between the two sub-arches and record the axial pressure of the elastic column. ; S304. Calculate the mutual influence coefficient between sub-arches. The mutual influence coefficient between sub-arches is used to characterize the amplification effect of the later-excavated sub-arch on the load of the earlier-excavated sub-arch. The calculation formula is as follows:

[0054] S305. Calculate the reinforcement coefficient of anchor bolt cross-lap joints. The anchor bolt cross-lap reinforcement coefficient is used to characterize the reinforcement effect of cross anchor bolts on the load in the cross-lap area. The calculation formula is as follows: .

[0055] Specifically, the mutual influence coefficient between sub-arches is quantitatively calculated using the pre-set structural column method. Cross-lap reinforcement factor with anchor bolts Specific methods include: (1) Establishing a numerical model The target cross-section of the super-large span chamber is divided according to sub-arches (e.g.) Figure 2 As shown, sub-arches can be numbered 1, 2, ..., n from left to right. The overall geostress field, model boundary conditions, and excavation sequence are set to establish a two-dimensional or three-dimensional excavation and support model containing sub-arch i, sub-arch i+1, and the anchor bolt overlap zone between them.

[0056] (2) Install elastic columns A high-stiffness elastic column is installed at the junction of sub-arch i and sub-arch i+1. The elastic modulus is taken as 100 to 200 times the elastic modulus of the surrounding rock to make it approximately rigid, thereby "sensing" the compressive stress at that location. The lower end of the column is fixed and the upper end is hinged, and the axial force of the column is recorded (the nodal reaction force is output by software).

[0057] (3) Step-by-step loading and recording 1. Excavate only the sub-arch i (apply system anchor bolts + shotcrete, without cross anchor bolts), and record the axial pressure of the elastic column. .

[0058] 2. Continue excavating sub-arch i+1 (same as above, only install its own system anchor bolts + shotcrete, do not install cross anchor bolts between the two sub-arches), and record the axial pressure of the elastic column. .

[0059] 3. Construct cross anchor bolts between sub-arches i and i+1 (the anchor bolt length should be able to penetrate into the loosened areas on both sides), and record the axial pressure of the elastic column. .

[0060] (4) Record the influence coefficient definition The influence coefficient of the excavation of the (i+1)th sub-arch on the load of the i-th sub-arch (i ≠ j > 1, indicating that the excavation of the sub-arch after the excavation of the first sub-arch increases the load of the first sub-arch).

[0061]

[0062] Instead of relying on empirical values, the value is calculated by back-calculating using the pre-set structural column method at the junction of the sub-arches (the "pre-set column back-calculation of anchor cable force" approach), and its value is >1. Define the anchor bolt cross-lap reinforcement factor (reflecting the degree to which cross anchor bolts further increase the load in the cross-lap area).

[0063] If the cross anchors significantly constrain the lateral deformation of the surrounding rock, resulting in a reduction in the height of the loosened zone... It may be slightly less than 1, but in most cases, due to load transfer, the pressure in the junction area increases. Greater than 1.

[0064] (5) Generalized influence coefficient considering distance attenuation For non-directly adjacent sub-arches (such as sub-arches i and i+2), if it is not possible to obtain the results directly through numerical simulation... When this is the case, a decay function can be used:

[0065] in Let α be the center distance between sub-arches i and j, and α be the attenuation coefficient (which can be taken as 1.0 to 2.0, and can be determined by numerical calibration). Alternatively, the above parameters can be obtained by directly modeling all sub-arch pairs.

[0066] Based on the above calculations, the output influence coefficient matrix is ​​as follows: (diagonal element) =1) The overlap reinforcement coefficient for each junction area is: , (corresponding to the junction area to the right of sub-arch i).

[0067] S400. Based on the reference load of a single sub-arch, combined with the mutual influence coefficients of all other sub-archs, span correction factor, distance attenuation coefficient, and anchor cross-lap reinforcement coefficient, the comprehensive vertical load of the sub-arch before applying prestressed anchor cables is calculated. In S400 of this embodiment, for each sub-arch i, its combined vertical load The formula for calculating the comprehensive vertical load of a sub-arch, determined by its own reference load, the superposition effect of all other sub-arches, and the reinforcement of cross-lap joints of anchor bolts, is as follows:

[0068] in, The vertical reference surrounding rock load for a single sub-arch is... This is the generalized influence coefficient. This is a span correction factor, reflecting the differences in the loosening range of sub-arches with different spans; The distance attenuation coefficient is calculated using the following formula:

[0069] in, Let be the center distance between sub-arches i and j. The distance attenuation coefficient for adjacent sub-arches is 1, and the distance attenuation coefficient for non-adjacent sub-arches is less than 1.

[0070] S500. Calculate the equivalent unloading pressure of the prestressed anchor cable, introduce an unloading coefficient to quantify the reduction effect of the active counter-tension of the anchor cable on the load of the main arch, correct the comprehensive load of the sub-arch, and obtain the final surrounding rock load after the anchor cable is installed. In S500 of this embodiment, the prestressed anchor cable arrangement scheme includes centralized and distributed types. For the centralized arrangement, the total tension of the anchor cables in the junction area is... The area of ​​influence of the anchor cable is centered on the center of the junction area, with an effective radius of influence. , Anchorage length; unloading coefficient The calculation formula is:

[0071] In the formula, The area of ​​the anchor cable's influence zone. The average value of the combined loads of the two adjacent sub-arches is taken as the comprehensive load of the junction area. For a distributed arrangement, spacing is applied radially along the parent arch. The anchor cables are installed, and the tension of a single anchor cable is... The equivalent unloading pressure across the entire cross section is calculated by integration, and then the unloading coefficient is solved.

[0072] In this embodiment, the unloading coefficient can also be calculated precisely using a preset structural column method. The specific method includes: Before and after applying anchor cable prestress in the numerical model, the axial pressure of the elastic column at the junction is recorded respectively. and The unloading coefficient is:

[0073] The revised final surrounding rock load is:

[0074] in, The total vertical load of the sub-arch.

[0075] S600. Based on the excavation and support status of each construction stage, calculate the final surrounding rock load of each sub-arch in the corresponding stage, extract the peak control load, and output the load envelope diagram and final cross-sectional load distribution of the construction stage.

[0076] In this embodiment, the design load combination is first output. For each construction step k (excavation to a certain sub-arch, before / after applying anchor bolts, etc.), the qipost of all excavated sub-arches is calculated, and the maximum value among them is taken as the control load of that step.

[0077] Based on the control load and safety factor KS, the key design parameters of anchor bolts, shotcrete, and anchor cables are calculated.

[0078] Then, the above methods are integrated into the design system, based on numerical simulation calculations (such as using FLAC3D or ABAQUS for full three-dimensional detailed simulation), and the above steps are compiled into a programmable module and embedded into the numerical simulation verification module to form the following functions: (1) Input interface: geological parameters, sub-arch geometric parameters, initial parameters of anchor bolts (cables), construction sequence; (2) Automatic calculation: qi0 → Preset column method to solve various influence coefficients ηi,i+1, ηlap,i, ηi,j → Solve the comprehensive load qitotal → Solve the corrected load qipost after considering the unloading coefficient of the prestressed anchor cable → Output the load curve; (3) Results visualization: Displays the load envelope diagram of the construction process, the load distribution diagram of the final section, and the concentrated force value of the junction area; (4) Iterative optimization: If the final calculated load does not match the preset anchor (cable) safety factor, the system will automatically suggest adjusting the anchor cable parameters and recalculate until parameters that meet the design requirements are given.

[0079] This embodiment discloses a method for determining the surrounding rock load of a parent-child composite arch structure, including: obtaining the geological, structural, and excavation parameters of the parent-child composite arch, and calculating the benchmark surrounding rock load of a single sub-arch; quantitatively calculating the mutual influence coefficient between sub-arches and the cross-lap reinforcement coefficient of anchor bolts using the pre-set structural column method, and solving the comprehensive load of the sub-arches by combining the distance attenuation characteristics; introducing the prestressed anchor cable unloading coefficient to quantify the unloading effect of active support, and correcting to obtain the final surrounding rock load; considering the longitudinal constraint effect of the tunnel face, outputting the peak load envelope diagram and the final long-term load distribution during the construction stage. This invention solves the problem of the inability to quantitatively and analytically calculate the surrounding rock load of ultra-large span parent-child composite arch structures, conforms to the construction sequence and structural mechanical characteristics, has high calculation accuracy, and can be programmed, providing a reliable basis for the support design of deep ultra-large span caverns.

[0080] Based on the same inventive concept, embodiments of the present invention also provide a system for determining the surrounding rock load of a mother-daughter combined bearing arch, employing the aforementioned method for determining the surrounding rock load of a mother-daughter combined arch, such as... Figure 3 It includes: a parameter input module, a reference load calculation module, an influence coefficient calculation module, a comprehensive load calculation module, a load correction module, and a result output module; among which: The parameter input module is used to obtain the basic input parameters for determining the surrounding rock load of the parent-child composite arch; the basic input parameters include geological parameters, parent-child composite arch structural parameters, excavation parameters, and calculation control parameters. The benchmark load calculation module is used to calculate the vertical benchmark surrounding rock load of a single sub-arch in isolated excavation state based on geological parameters and sub-arch geometric parameters. The influence coefficient calculation module is used to establish a numerical model of sub-arch excavation and support. High-rigidity elastic columns are set at the junction of adjacent sub-arches. Through step-by-step excavation and support construction, the axial reaction force of the elastic columns under different working conditions is recorded. Based on the reaction force ratio, the mutual influence coefficient between sub-arches and the cross-lap joint reinforcement coefficient of anchor bolts are calculated. The comprehensive load calculation module is used to calculate the comprehensive vertical load of the sub-arch before the application of prestressed anchor cables, based on the reference load of a single sub-arch and combined with the mutual influence coefficients of all other sub-archs, span correction factor, distance attenuation coefficient, and anchor cross-lap reinforcement coefficient. The load correction module is used to calculate the equivalent unloading pressure of the prestressed anchor cable, introduce an unloading coefficient to quantify the reduction effect of the active counter-tension of the anchor cable on the load of the main arch, correct the comprehensive load of the sub-arch, and obtain the final surrounding rock load after the anchor cable is installed. The results output module is used to calculate the final surrounding rock load of each sub-arch in the corresponding stage based on the excavation and support status of each construction stage, extract the peak control load, and output the load envelope diagram and final cross-sectional load distribution of the construction stage.

[0081] The specific working methods of the parameter input module, the reference load calculation module, the influence coefficient calculation module, the comprehensive load calculation module, the load correction module, and the result output module have been described in detail in the above-mentioned method for determining the surrounding rock load of a mother-daughter combined bearing arch, and will not be repeated here in this embodiment.

[0082] Based on the same inventive concept, embodiments of the present invention also provide an electronic device. Figure 4 This is a structural block diagram of an electronic device provided in an embodiment of the present invention. Figure 4 As shown, an embodiment of the present invention provides an electronic device including: one or more processors 101, a memory 102, and one or more I / O interfaces 103. The memory 102 stores one or more programs, which, when executed by the one or more processors, cause the one or more processors to implement any of the methods described in the above embodiments; the one or more I / O interfaces 103 are connected between the processor and the memory, configured to enable information interaction between the processor and the memory.

[0083] The processor 101 is a device with data processing capabilities, including but not limited to a central processing unit (CPU); the memory 102 is a device with data storage capabilities, including but not limited to random access memory (RAM, more specifically SDRAM, DDR, etc.), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and flash memory (FLASH); the I / O interface (read / write interface) 103 is connected between the processor 101 and the memory 102, and can realize information interaction between the processor 101 and the memory 102, including but not limited to a data bus (Bus).

[0084] In some embodiments, the processor 101, memory 102, and I / O interface 103 are interconnected via bus 104, and thus connected to other components of the computing device.

[0085] In some embodiments, the one or more processors 101 include a field-programmable gate array.

[0086] This invention also provides a computer-readable medium. The computer-readable medium stores a computer program, which, when executed by a processor, implements the steps of any of the methods described in the above embodiments. The computer-readable storage medium may be a volatile or non-volatile computer-readable storage medium.

[0087] This invention also provides a computer program product, including computer-readable code, or a non-volatile computer-readable storage medium carrying computer-readable code, wherein when the computer-readable code is run in the processor of an electronic device, the processor in the electronic device executes the above-described method.

[0088] Those skilled in the art will understand that all or some of the steps, systems, and apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software can be distributed on a computer-readable storage medium, which may include computer storage media (or non-transitory media) and communication media (or transient media).

[0089] As is known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable program instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), flash memory or other memory technologies, portable compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, it is known to those skilled in the art that communication media typically contain computer-readable program instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0090] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0091] The computer program instructions used to perform the operations of this invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via 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., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of the invention.

[0092] The computer program product described herein can be implemented specifically through hardware, software, or a combination thereof. In one alternative embodiment, the computer program product is specifically embodied in a computer storage medium; in another alternative embodiment, the computer program product is specifically embodied in a software product, such as a software development kit (SDK), etc.

[0093] Various aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0094] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0095] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0096] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0097] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A method for determining the surrounding rock load of a mother-daughter combined bearing arch, characterized in that, include: S100. Obtain the basic input parameters for determining the surrounding rock load of the parent-child composite arch; the basic input parameters include geological parameters, parent-child composite arch structural parameters, excavation parameters, and calculation control parameters; S200. Calculate the vertical reference surrounding rock load of a single sub-arch under isolated excavation conditions based on geological parameters and sub-arch geometric parameters; S300. Establish a numerical model for the excavation and support of the sub-arches. Set up high-rigidity elastic columns at the junction of adjacent sub-arches. Through step-by-step excavation and support construction, record the axial reaction force of the elastic columns under different working conditions. Calculate the mutual influence coefficient between sub-arches and the cross-lap reinforcement coefficient of anchor bolts based on the reaction force ratio. S400. Based on the reference load of a single sub-arch, combined with the mutual influence coefficients of all other sub-archs, span correction factor, distance attenuation coefficient, and anchor cross-lap reinforcement coefficient, the comprehensive vertical load of the sub-arch before applying prestressed anchor cables is calculated. S500. Calculate the equivalent unloading pressure of the prestressed anchor cable, introduce an unloading coefficient to quantify the reduction effect of the active counter-tension of the anchor cable on the load of the main arch, correct the comprehensive load of the sub-arch, and obtain the final surrounding rock load after the anchor cable is installed. S600. Based on the excavation and support status of each construction stage, calculate the final surrounding rock load of each sub-arch in the corresponding stage, extract the peak control load, and output the load envelope diagram and final cross-sectional load distribution of the construction stage.

2. The method according to claim 1, characterized in that, In S100: the geological parameters include the unit weight of the surrounding rock γ, the angle of internal friction φ, the cohesion c, the uniaxial compressive strength Rc, the Protodyakonov strongness coefficient f, and the surrounding rock grade S; the structural parameters of the parent-child composite arch include the number of child arches n and the span of each child arch. , the height of each sub-arch Length of the cross-overlap zone of anchor bolts between sub-arches Parameters for the prestressed anchor cable arrangement scheme; the excavation parameters include the excavation sequence of each sub-arch and the excavation lag of each sub-arch relative to the first sub-arch. The calculated control parameters include the tunnel burial depth H and the safety factor of the support structure. .

3. The method according to claim 1, characterized in that, In S200, the Protodyakonov formula is used to calculate the vertical reference surrounding rock load of a single sub-arch. The calculation formula is: ； in, , which is the number of sub-arches, and f is the strength coefficient, which can be obtained from a table based on the hardness of the surrounding rock; For the span of the sub-arch, Φ is the arch height, f is the internal friction angle of the surrounding rock, f is the Protodyakonov hardness coefficient, and γ is the unit weight of the surrounding rock.

4. The method according to claim 1, characterized in that, The specific methods of S300 include: S301. Establish a numerical model of excavation and support that includes the intersection of adjacent sub-arches and anchor bolts, set the in-situ stress field and boundary conditions, and define the excavation and support steps according to the construction sequence. S302. A high-rigidity elastic column is set at the junction of the i-th sub-arch and the (i+1)-th sub-arch. The elastic modulus of the elastic column is a preset multiple of the elastic modulus of the surrounding rock. The lower end of the column is fixed and the upper end is hinged. It is used to sense the compressive stress at the junction. S303. Step-by-step loading and reaction force recording: The first step involves excavating only the i-th sub-arch and installing its own system of anchor bolts and shotcrete, without installing cross anchor bolts, and recording the axial pressure of the elastic column. ; The second step involves continuing to excavate the (i+1)th sub-arch and installing its own system of anchor bolts and shotcrete, without installing cross anchor bolts, and recording the axial pressure of the elastic column. ; The third step is to install the cross anchor bolts between the two sub-arches and record the axial pressure of the elastic column. ; S304. Calculate the mutual influence coefficient between sub-arches. The mutual influence coefficient between sub-arches is used to characterize the amplification effect of the later-excavated sub-arch on the load of the earlier-excavated sub-arch. The calculation formula is as follows: ； S305. Calculate the reinforcement coefficient of anchor bolt cross-lap joints. The anchor bolt cross-lap reinforcement coefficient is used to characterize the reinforcement effect of cross anchor bolts on the load in the cross-lap area. The calculation formula is as follows: 。 5. The method according to claim 4, characterized in that, S300 also includes the calculation of the generalized influence coefficient of non-adjacent sub-arches. For the i-th sub-arch and the j-th sub-arch that are not directly adjacent, the generalized influence coefficient is calculated using an exponential decay function. The calculation formula is as follows: ； in, The center distance between sub-arches i and j. , Let α be the span of the sub-arch, and α be the attenuation coefficient.

6. The method according to claim 1, characterized in that, In S400, the formula for calculating the combined vertical load of the sub-arch is: ； in, The vertical reference surrounding rock load for a single sub-arch is... This is the generalized influence coefficient. This is a span correction factor, reflecting the differences in the loosening range of sub-arches with different spans; The distance attenuation coefficient is calculated using the following formula: ； in, Let be the center distance between sub-arches i and j. The distance attenuation coefficient for adjacent sub-arches is 1, and the distance attenuation coefficient for non-adjacent sub-arches is less than 1.

7. The method according to claim 1, characterized in that, In S500, the prestressed anchor cable arrangement scheme includes centralized and distributed types. For the centralized arrangement, the total tension of the anchor cables in the junction area is... The area of ​​influence of the anchor cable is centered on the center of the junction area, with an effective radius of influence. , Anchorage length; unloading coefficient The calculation formula is: ； In the formula, The area of ​​the anchor cable's influence zone. The average value of the combined loads of the two adjacent sub-arches is taken as the comprehensive load of the junction area. For a distributed arrangement, spacing is applied radially along the parent arch. The anchor cables are installed, and the tension of a single anchor cable is... The equivalent unloading pressure across the entire cross section is calculated by integration, and then the unloading coefficient is solved.

8. The method according to claim 7, characterized in that, The unloading coefficient can also be calculated precisely using the preset structural column method, the specific method of which includes: Before and after applying anchor cable prestress in the numerical model, the axial pressure of the elastic column at the junction is recorded respectively. and The unloading coefficient is: ； The revised final surrounding rock load is: ； in, The total vertical load of the sub-arch.

9. A system for determining the surrounding rock load of a mother-daughter combined bearing arch, employing any one of the methods described in claims 1-8, characterized in that, include: The module includes a parameter input module, a reference load calculation module, an influence coefficient calculation module, a comprehensive load calculation module, a load correction module, and a result output module; among which: The parameter input module is used to obtain the basic input parameters for determining the surrounding rock load of the parent-child composite arch; the basic input parameters include geological parameters, parent-child composite arch structural parameters, excavation parameters, and calculation control parameters. The benchmark load calculation module is used to calculate the vertical benchmark surrounding rock load of a single sub-arch in isolated excavation state based on geological parameters and sub-arch geometric parameters. The influence coefficient calculation module is used to establish a numerical model of sub-arch excavation and support. High-rigidity elastic columns are set at the junction of adjacent sub-arches. Through step-by-step excavation and support construction, the axial reaction force of the elastic columns under different working conditions is recorded. Based on the reaction force ratio, the mutual influence coefficient between sub-arches and the cross-lap joint reinforcement coefficient of anchor bolts are calculated. The comprehensive load calculation module is used to calculate the comprehensive vertical load of the sub-arch before the application of prestressed anchor cables, based on the reference load of a single sub-arch and combined with the mutual influence coefficients of all other sub-archs, span correction factor, distance attenuation coefficient, and anchor cross-lap reinforcement coefficient. The load correction module is used to calculate the equivalent unloading pressure of the prestressed anchor cable, introduce an unloading coefficient to quantify the reduction effect of the active counter-tension of the anchor cable on the load of the main arch, correct the comprehensive load of the sub-arch, and obtain the final surrounding rock load after the anchor cable is installed. The results output module is used to calculate the final surrounding rock load of each sub-arch in the corresponding stage based on the excavation and support status of each construction stage, extract the peak control load, and output the load envelope diagram and final cross-sectional load distribution of the construction stage.

10. An electronic device, characterized in that, include: One or more processors; Memory, used to store 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 method as described in any one of claims 1 to 8.

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