A method and system for determining a control parameter of stability of a roadway surrounding rock

Abstract

The application discloses a kind of determination method and system of roadway surrounding rock stability control parameter.It is determined that method includes: receiving input parameter, including tectonic stress grade identification, overburden average specific gravity, roadway buried depth, surrounding rock lithology information, component span and concrete compressive strength;Determine lateral pressure coefficient based on tectonic stress grade identification and query preset mapping table, calculate basic lateral ground stress;According to surrounding rock lithology information, it is judged whether it belongs to soft rock category, if it is, according to softening degree, another mapping table is inquired to obtain correction coefficient, and the basic stress is softened and expanded to correct, to obtain the modified lateral ground stress value;Using the correction stress value, component span and concrete compressive strength, the design thickness of stress self-balancing precast component is calculated by the formula of built-in comprehensive safety factor;Finally, the modified lateral ground stress value and component design thickness are output, and support scheme early warning can be output when stress value is too high.

Description

Technical Field

[0001] This invention relates to the field of tunnel surrounding rock stability detection technology, and particularly to a method and system for determining tunnel surrounding rock stability control parameters. Background Technology

[0002] In underground engineering projects such as mining, transportation tunnels, and water conservancy culverts, the stability of the surrounding rock directly affects project safety, construction costs, and long-term operational reliability. Ensuring tunnel stability hinges on designing a reasonable support structure and parameters, based on an accurate assessment of the loads on the surrounding rock, particularly lateral stresses, and the scientific determination of key dimensions (such as thickness) of the support components.

[0003] Traditional methods for analyzing the stability of surrounding rock in tunnels and designing support parameters primarily rely on simplified theoretical formulas, engineering analogies, and limited geological survey and laboratory test data. A common approach is to estimate vertical stress using formulas based on the Kinnick or Heim hypothesis, then extrapolate horizontal stress using empirical Poisson's ratio values ​​of the rock mass, and finally design the support. This approach has significant limitations: First, it severely undervalues ​​geological tectonic stress. In actual engineering, horizontal stress is often composed of the rock mass's own weight and residual stress generated by tectonic movements throughout geological history, and in areas of intense tectonic activity, tectonic stress may become the dominant factor. Traditional methods typically use only a fixed lateral pressure coefficient (often based on Poisson's ratio) to reflect the relationship between horizontal and vertical stress, failing to systematically distinguish the significant differences between different tectonic stress levels (such as weak tectonic zones and strong compression zones), leading to potentially large deviations in the estimation of lateral loads from reality. Second, it does not adequately consider the time-varying deterioration characteristics of the surrounding rock, especially soft rock. Soft rocks such as mudstone and shale are easily softened, muddied, and expanded by water and wind in underground engineering environments. Their strength decreases over time and may generate continuously increasing nonlinear additional loads on the support structure. Traditional design methods often treat rock mass parameters as static values ​​and lack quantitative correction mechanisms for these time-varying effects. This results in underestimation of design loads, which can easily lead to deformation, cracking, or even failure of the support structure in later stages. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method and system for determining the stability control parameters of roadway surrounding rock, so as to solve the problems mentioned in the background art.

[0005] The main objective of this application is to provide a method for determining the stability control parameters of roadway surrounding rock, comprising the following steps: Receive input parameters, which include structural stress level identifier, average unit weight γ of overlying strata, tunnel burial depth H, surrounding rock lithology information, component span L, and concrete compressive strength fc. Based on the structural stress level identifier, the pre-stored structural stress-lateral pressure coefficient mapping table is queried to determine the corresponding lateral pressure coefficient λ. Using the lateral pressure coefficient λ, the average unit weight γ of the overlying strata, and the tunnel burial depth H, the lateral stress value σ of the foundation is calculated. h = λ × γ × H; Based on the surrounding rock lithology information, determine whether the surrounding rock of the roadway belongs to the preset soft rock category; When the rock is determined to be soft rock, the softening degree-correction coefficient mapping table is consulted based on the softening degree determined on-site or in the laboratory to obtain the mudstone softening and expansion correction coefficient k. The foundation lateral stress value σ h Combined with the mudstone softening and expansion correction factor k, the corrected lateral stress value P = σ is calculated. h × (1 + k); When it is determined that the rock does not belong to the soft rock category, the foundation lateral stress value σ is directly applied. h The corrected lateral stress value P; Based on the corrected lateral stress value P, the span L of the component, and the compressive strength fc of the concrete, the design thickness t of the stress-self-balancing precast component is calculated as: t = 1.5 × P × L / (2 × fc) c ); Output the corrected lateral stress value P and the design thickness t.

[0006] Furthermore, the pre-stored structural stress-lateral pressure coefficient mapping table includes: When the tectonic stress level is identified as weak horizontal tectonic stress, the corresponding lateral pressure coefficient λ is 0.3 to 0.5; when the tectonic stress level is identified as a normal sedimentary environment, the corresponding lateral pressure coefficient λ is 0.5 to 1.0; when the tectonic stress level is identified as a strong tectonic stress zone, the corresponding lateral pressure coefficient λ is 1.0 to 2.0; when the tectonic stress level is identified as an extremely strong tectonic zone, the corresponding lateral pressure coefficient λ is greater than 2.0.

[0007] Furthermore, the softening degree-correction coefficient mapping table includes: when the softening degree is weak, the corresponding mudstone softening and expansion correction coefficient k is 0.1 to 0.2; when the softening degree is moderate, the corresponding mudstone softening and expansion correction coefficient k is 0.2 to 0.4; and when the softening degree is strong, the corresponding mudstone softening and expansion correction coefficient k is 0.4 to 0.7.

[0008] Furthermore, the determination of whether the surrounding rock of the tunnel belongs to the preset soft rock category includes: The surrounding rock lithology information is compared with a preset soft rock lithology list; If the surrounding rock lithology information exists in the soft rock lithology list, it is determined to belong to the soft rock category; If it does not exist, it is determined that it does not belong to the soft rock category.

[0009] Further, after outputting the corrected lateral stress value P and the design thickness t, the following steps are executed: The corrected lateral stress value P is compared with a preset high stress threshold. If the corrected lateral stress value P is greater than the high stress threshold, then a warning message is generated and output to prompt the adoption of a support scheme with stress self-balancing or reverse bearing structure.

[0010] The present invention also provides a system for confirming the stability control parameters of roadway surrounding rock, comprising: The parameter input module is used to receive input parameters, including structural stress level identifier, average unit weight γ of overlying strata, tunnel burial depth H, surrounding rock lithology information, component span L, and concrete compressive strength f_c. The lateral pressure coefficient mapping module is connected to the parameter input module and is used to query the pre-stored structural stress-lateral pressure coefficient mapping table based on the structural stress level identifier to determine the corresponding lateral pressure coefficient λ. The foundation stress calculation module, connected to the lateral pressure coefficient mapping module and the parameter input module, is used to calculate the foundation lateral stress value σ using the lateral pressure coefficient λ, the average unit weight γ of the overlying strata, and the tunnel burial depth H. h = λ × γ × H; The lithology discrimination module is connected to the parameter input module and is used to determine whether the surrounding rock of the roadway belongs to a preset soft rock category based on the surrounding rock lithology information. The softening correction module, connected to the lithology discrimination module, is used to obtain the mudstone softening and expansion correction coefficient k by querying the softening degree-correction coefficient mapping table based on the softening degree determined on-site or in the laboratory when the mudstone is determined to be of the soft rock category. The integrated stress calculation module, connected to the foundation stress calculation module and the softening correction module, is used to calculate the lateral ground stress value σ of the foundation. h Combined with the mudstone softening and expansion correction factor k, the corrected lateral stress value P = σ is calculated. h × (1 + k); When the lithology discrimination module determines that it does not belong to the soft rock category, the foundation lateral stress value σh is directly used as the corrected lateral stress value P. The component thickness calculation module, connected to the comprehensive stress calculation module and the parameter input module, is used to calculate the thickness based on the corrected lateral stress value P, the component span L, and the concrete compressive strength f.c The design thickness t of the stress-self-balancing precast component is calculated as: t = 1.5 × P × L / (2 × f) c ); The result output module is connected to the comprehensive stress calculation module and the component thickness calculation module, and is used to output the corrected lateral stress value P and the design thickness t.

[0011] Furthermore, after calculating the corrected lateral stress value P, the integrated stress calculation module also performs the following: The corrected lateral stress value P is compared with a preset high stress threshold. If the corrected lateral stress value P is greater than the high stress threshold, then an early warning message is generated to suggest the use of a support scheme with stress self-balancing or reverse bearing structure. The result output module is also used to output early warning information for the support scheme.

[0012] Furthermore, the softening correction module is configured to activate and perform the operation of querying the softening degree-correction coefficient mapping table only when it receives a judgment signal output by the lithology discrimination module indicating that it belongs to the soft rock category.

[0013] Furthermore, the lithology discrimination module specifically comprises: It includes a soft rock lithology list storage unit for storing the preset soft rock lithology list; The lithology discrimination module completes the judgment by comparing the lithology information of the surrounding rock with the soft rock lithology list.

[0014] Furthermore, after the result output module outputs the design thickness t, it recommends matching standard component specifications for the design thickness t based on the pre-stored component specification library.

[0015] By establishing and querying a tectonic stress-lateral pressure coefficient mapping table, the qualitative description of the geological tectonic environment is transformed into a quantifiable range of lateral pressure coefficient λ values. The mapping table is based on statistical summarization of extensive measured geostress data from mining areas and historical data on geological tectonic activity, covering multi-level correspondences from weak tectonic stress to extremely strong tectonic zones. This rapid and reliable conversion from macroscopic geological judgments to specific engineering parameters is particularly suitable for engineering stages lacking detailed measured geostress data.

[0016] The surrounding rock is identified as soft rock using a pre-set soft rock lithology list and quantitative criteria. If identified as soft rock, the softening degree (weak, medium, strong) determined on-site or in the laboratory is further queried from a softening degree-correction coefficient mapping table to obtain the corresponding mudstone softening and expansion correction coefficient k (range 0.1–0.7). The strength attenuation and volume expansion effects of soft rock due to water exposure and weathering during the engineering service period are condensed into a load increment coefficient k, and expressed by the formula P = σ h × (1 + k) incorporates this time-varying additional load into the lateral geostress correction. This breaks through the limitation of treating the rock mass as a static mechanical medium in traditional design, and explicitly considers the time-varying deterioration characteristics of soft rock; by quantifying the correction coefficient k, the design load more realistically reflects the most unfavorable state under long-term interaction with the surrounding rock; and by combining the dual judgment mechanism of laboratory softening coefficient and field phenomena, the objectivity and accuracy of softening degree assessment are improved. Attached Figure Description

[0017] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a flowchart of the method for constructing the acquisition layer in this invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 The main objective of this application is to provide a method for determining the stability control parameters of roadway surrounding rock, comprising the following steps: receiving input parameters, wherein the input parameters include tectonic stress level identifier, average unit weight γ of overlying strata, roadway burial depth H, surrounding rock lithology information, component span L, and concrete compressive strength f. c Based on the tectonic stress level identifier, the pre-stored tectonic stress-lateral pressure coefficient mapping table is queried to determine the corresponding lateral pressure coefficient λ; using the lateral pressure coefficient λ, the average unit weight γ of the overlying strata, and the tunnel burial depth H, the foundation lateral stress value σ is calculated. h = λ × γ × H; Based on the surrounding rock lithology information, determine whether the surrounding rock of the tunnel belongs to the preset soft rock category; when it is determined to belong to the soft rock category, according to the softening degree determined on site or in the laboratory, query the softening degree-correction coefficient mapping table to obtain the mudstone softening and expansion correction coefficient k; and set the foundation lateral stress value σ hCombined with the mudstone softening and expansion correction factor k, the corrected lateral stress value P = σ is calculated. h × (1 + k); When it is determined that the rock does not belong to the soft rock category, the foundation lateral stress value σ is directly applied. h The corrected lateral stress value P; based on the corrected lateral stress value P, the member span L, and the concrete compressive strength f. c The design thickness t of the stress-self-balancing precast component is calculated as: t = 1.5 × P × L / (2 × f) c Output the corrected lateral stress value P and the design thickness t.

[0020] Before receiving input parameters, the process includes parameter acquisition and preprocessing steps: S1: Obtain the average unit weight γ of the overlying strata and the tunnel burial depth H from the geological survey report, and use in-situ stress testing or a regional geostress database to help determine the tectonic stress level identifier; S2: Obtain the lithology information and uniaxial compressive strength of the surrounding rock through core drilling and laboratory rock mechanics tests, and automatically classify lithologies with uniaxial compressive strength lower than the preset soft rock strength threshold into the preset soft rock category; S3: Perform on-site measurement and verification of the component span L to ensure that it is the design net span of the tunnel or the key bearing span of the support structure; S4: Based on the concrete compressive strength f c The design design number is used to obtain the standard or design value from the material specifications, which is then used as input for calculations.

[0021] After outputting the corrected lateral stress value P and the design thickness t, a verification and feedback step is included: substituting the design thickness t into a preset beam-slab structural mechanics model to perform ultimate limit state calculation of bearing capacity, and checking whether the maximum bending stress of the member is less than 0.85 × f under the action of a uniformly distributed lateral load P. c And whether the maximum deflection is less than L / 250; if the verification passes, the design thickness t is rounded to the modular thickness of the standard precast component, and the final recommended thickness is output; if the verification fails, the value of the design thickness t is automatically increased iteratively, and the verification is re-performed until the requirements are met, and the iteration process and the final thickness are recorded.

[0022] In some embodiments, the pre-stored tectonic stress-lateral pressure coefficient mapping table includes: when the tectonic stress level is identified as weak horizontal tectonic stress, the corresponding lateral pressure coefficient λ is 0.3 to 0.5; when the tectonic stress level is identified as a normal depositional environment, the corresponding lateral pressure coefficient λ is 0.5 to 1.0; when the tectonic stress level is identified as a strong tectonic stress zone, the corresponding lateral pressure coefficient λ is 1.0 to 2.0; and when the tectonic stress level is identified as an extremely strong tectonic zone, the corresponding lateral pressure coefficient λ is greater than 2.0.

[0023] The determination of the lateral pressure coefficient λ depends on the angle θ between the roadway axis and the direction of the maximum horizontal principal stress in the region: when the angle θ is less than 30°, the value obtained from the structural stress-lateral pressure coefficient mapping table is multiplied by a directional influence coefficient of 1.0 to 1.2; when the angle θ is between 30° and 60°, the directional influence coefficient is 0.8 to 1.0; when the angle θ is greater than 60°, the directional influence coefficient is 0.6 to 0.8. The final lateral pressure coefficient λ' = λ × directional influence coefficient.

[0024] When the roadway is located within the lateral support pressure zone of the goaf, the calculation of the foundation lateral stress value σh needs to introduce the stress concentration factor K: First, determine the initial lateral pressure factor λ according to the structural stress level identifier; then, determine the stress concentration factor K by referring to the table according to the ratio of the distance of the roadway from the edge of the goaf to the thickness of the key layer of the overlying strata, and its value range is 1.2~3.0; finally, calculate the foundation lateral stress value σh = K × λ × γ × H.

[0025] In some embodiments, the softening degree-correction coefficient mapping table includes: when the softening degree is weak, the corresponding mudstone softening and expansion correction coefficient k is 0.1 to 0.2; when the softening degree is moderate, the corresponding mudstone softening and expansion correction coefficient k is 0.2 to 0.4; and when the softening degree is strong, the corresponding mudstone softening and expansion correction coefficient k is 0.4 to 0.7.

[0026] The degree of softening is determined based on the ratio R of the laboratory saturated uniaxial compressive strength to the natural uniaxial compressive strength. s When R s When R > 0.75, it is judged as weakly softened; when 0.5 < R s When R ≤ 0.75, it is judged as moderate softening; when R s When the density is ≤0.5, it is considered strongly softened. If there is no laboratory data, the qualitative judgment is made based on the phenomenon of water immersion and disintegration of the core sample: slow mudification indicates weak softening, rapid fragmentation indicates moderate softening, and rapid disintegration indicates strongly softening.

[0027] In the above embodiments, the pre-stored tectonic stress-lateral pressure coefficient mapping table is established and maintained through the following steps: collecting historical data on geological tectonic activity, field measurement data of geostress, and corresponding geological environment descriptions of multiple typical mining areas; performing statistical analysis on the field measurement data of geostress, calculating the ratio of average level geostress to vertical geostress in each mining area, and using it as the measured benchmark for the lateral pressure coefficient λ; dividing the mining area into four levels based on the intensity of historical geological tectonic activity: weak horizontal tectonic stress, normal sedimentary environment, strong tectonic stress zone, and extremely strong tectonic zone, as tectonic stress level identifiers; associating and matching the tectonic stress level identifier of each mining area with its corresponding measured benchmark range for the lateral pressure coefficient λ to form an initial mapping table; continuously collecting data on the selection of tectonic stress level identifiers and actual engineering feedback when using this method for calculation, and calibrating and updating the range of lateral pressure coefficient λ values ​​under a certain level identifier when a systematic deviation occurs in the engineering feedback under that level identifier, so as to achieve dynamic optimization of the mapping table.

[0028] The determination of whether the surrounding rock of the tunnel belongs to a preset soft rock category includes: comparing the lithological information of the surrounding rock with a preset soft rock lithology list, which at least includes mudstone, carbonaceous mudstone, bentonite, and severely weathered sandy mudstone; if the lithological information of the surrounding rock exists in the soft rock lithology list, it is preliminarily determined that it belongs to the soft rock category; after the preliminary determination, the uniaxial saturated compressive strength Rc and softening coefficient η of the surrounding rock are further obtained; if the uniaxial saturated compressive strength Rc is higher than the softening coefficient η, the determination is further made based on the following criteria: c If the strength is less than a preset threshold and the softening coefficient η is less than a preset threshold, then it is finally determined to belong to the soft rock category; if the surrounding rock lithology information does not exist in the soft rock lithology list, or although it exists, the uniaxial saturated compressive strength Rc and the softening coefficient η do not meet the quantitative criteria for soft rock, then it is determined not to belong to the soft rock category.

[0029] The degree of softening determined by on-site or laboratory testing specifically includes: the degree of softening is determined by quantitative indicators obtained through on-site investigation or laboratory testing; wherein, the degree of softening determined by on-site investigation is based on: the severity of surface mudification and detachment of the surrounding rock after it comes into contact with water, the disintegration rate and amount of the borehole core after immersion in water, and the time period during which the strength of the surrounding rock deteriorates when exposed to humid air after tunnel excavation; the degree of softening determined by laboratory testing is based on: the ratio of uniaxial compressive strength of rock in dry state to that in saturated state as measured by rock mechanics tests, i.e., the softening coefficient η, and is judged according to the preset softening coefficient range and the correspondence between weak softening, moderate softening, and strong softening levels; when the on-site investigation phenomena and laboratory test results are inconsistent, the softening coefficient η of the laboratory test is given priority as the basis for querying the softening degree-correction coefficient mapping table.

[0030] Furthermore, determining whether the surrounding rock of the tunnel belongs to a preset soft rock category includes: comparing the lithological information of the surrounding rock with a preset soft rock lithology list; if the lithological information of the surrounding rock exists in the soft rock lithology list, it is determined to belong to the soft rock category; if it does not exist, it is determined not to belong to the soft rock category.

[0031] The preset soft rock lithology list includes not only lithology names but also corresponding rock strength coefficient f value ranges. If the surrounding rock lithology information exists in the list and the rock mass integrity index from the field investigation is less than 50%, it is directly identified as the soft rock category. If the lithology information is not in the list, but the uniaxial compressive strength obtained by back-calculation through point load test or rebound hammer test is less than 15 MPa, it is also supplemented and identified as the soft rock category.

[0032] Further, after outputting the corrected lateral stress value P and the design thickness t, the following steps are performed: comparing the corrected lateral stress value P with a preset high stress threshold; if the corrected lateral stress value P is greater than the high stress threshold, then a warning message is generated and output to prompt the adoption of a support scheme with stress self-balancing or reverse bearing structure.

[0033] The high stress threshold is not a fixed value, but is dynamically set based on the surrounding rock lithology information: for hard, intact rock masses (such as granite and limestone), the high stress threshold is set to 0.4 × γ × H; for medium-hard rock masses (such as sandstone and sandy shale), the high stress threshold is set to 0.3 × γ × H; and for the soft rock category, the high stress threshold is set to 0.25 × γ × H. When P exceeds the corresponding threshold, a warning of the corresponding level is triggered.

[0034] The specific early warning information for the support scheme includes: when P exceeds the high stress threshold but is less than 1.5 times the threshold, it is recommended to use high-strength prestressed anchor bolts (cables) in conjunction with the stress self-balancing precast components for joint support; when P is greater than or equal to 1.5 times the threshold, it is recommended to use a closed anti-arch roadway structure or double-layer nested stress self-balancing precast components for strong support, and strengthen the treatment of the roadway floor.

[0035] Example 2 This invention also provides a system for confirming the stability control parameters of roadway surrounding rock, comprising: a parameter input module for receiving input parameters, wherein the input parameters include tectonic stress level identifier, average unit weight γ of overlying strata, roadway burial depth H, surrounding rock lithology information, component span L, and concrete compressive strength f. cThe lateral pressure coefficient mapping module, connected to the parameter input module, is used to query a pre-stored tectonic stress-lateral pressure coefficient mapping table based on the tectonic stress level identifier to determine the corresponding lateral pressure coefficient λ. The foundation stress calculation module, connected to both the lateral pressure coefficient mapping module and the parameter input module, is used to calculate the foundation lateral stress value σ using the lateral pressure coefficient λ, the average unit weight γ of the overlying strata, and the tunnel burial depth H. h = λ × γ × H; Lithology discrimination module, connected to the parameter input module, is used to determine whether the surrounding rock of the tunnel belongs to a preset soft rock category based on the surrounding rock lithology information; Softening correction module, connected to the lithology discrimination module, is used to, when determined to belong to the soft rock category, query the softening degree-correction coefficient mapping table according to the softening degree determined on site or in the laboratory to obtain the mudstone softening and expansion correction coefficient k; Comprehensive stress calculation module, connected to the foundation stress calculation module and the softening correction module, is used to calculate the foundation lateral stress value σ h Combined with the mudstone softening and expansion correction factor k, the corrected lateral stress value P = σ is calculated. h × (1 + k); When the lithology discrimination module determines that it does not belong to the soft rock category, the foundation lateral stress value σh is directly used as the corrected lateral stress value P; The component thickness calculation module is connected to the comprehensive stress calculation module and the parameter input module, and is used to calculate the thickness based on the corrected lateral stress value P, the component span L, and the concrete compressive strength f. c The design thickness t of the stress-self-balancing precast component is calculated as: t = 1.5 × P × L / (2 × f) c The result output module is connected to the comprehensive stress calculation module and the component thickness calculation module, and is used to output the corrected lateral stress value P and the design thickness t.

[0036] The parameter input module also includes a data verification unit and a default value recommendation unit: the data verification unit is used to check the rationality and logical consistency of the numerical range of the input parameters and to provide alerts for abnormal values; the default value recommendation unit, when some parameters are missing, selects typical values ​​from the built-in engineering database to recommend and fill them in based on the input tunnel burial depth H and surrounding rock lithology information.

[0037] Furthermore, after calculating the corrected lateral stress value P, the integrated stress calculation module also performs the following: comparing the corrected lateral stress value P with a preset high stress threshold; if the corrected lateral stress value P is greater than the high stress threshold, then generating early warning information to prompt the adoption of a support scheme using stress self-balancing or reverse bearing structure; the result output module is also used to output the early warning information of the support scheme.

[0038] Furthermore, the softening correction module is configured to activate and perform the operation of querying the softening degree-correction coefficient mapping table only when it receives a judgment signal output by the lithology discrimination module indicating that it belongs to the soft rock category.

[0039] Furthermore, the lithology discrimination module specifically includes a soft rock lithology list storage unit for storing the preset soft rock lithology list; the lithology discrimination module completes the judgment by comparing the surrounding rock lithology information with the soft rock lithology list.

[0040] Furthermore, after the result output module outputs the design thickness t, it recommends matching standard component specifications for the design thickness t based on the pre-stored component specification library.

[0041] The above includes information such as structural stress level identifier, average unit weight γ of overlying strata, tunnel burial depth H, surrounding rock lithology information, component span L, and concrete compressive strength f. c The input parameters are used to systematically model the stability problem of the surrounding rock in the tunnel. All key variables are integrated into an initial condition set, in which the tectonic stress level identifier, along with γ and H, defines the original three-dimensional stress field environment of the surrounding rock. The lithological information of the surrounding rock characterizes the physical and mechanical properties of the medium itself and its potential time-varying behavior, while the component span L and material strength f... c This constitutes the design boundary and resistance basis of the support structure.

[0042] Based on the tectonic stress level identifier, a pre-stored tectonic stress-lateral pressure coefficient mapping table is used to determine the lateral pressure coefficient λ, thus transforming macroscopic geological qualitative judgment into a quantitative mechanical parameter for engineering applications. Classical geostress theory connects vertical and horizontal stresses in ideal isotropic rock masses solely through Poisson's ratio. However, actual rock masses are profoundly affected by geological tectonic movements, with horizontal tectonic stress often becoming dominant. The mapping table (e.g., λ = 0.3~0.5 for weak tectonic stress, and λ > 2.0 for extremely strong tectonic zones) is essentially a database of statistical regularities and empirical summaries from extensive field geostress measurements, geological structural analysis, and engineering inversion cases. It does not seek precise theoretical formulas, but rather establishes an empirical correspondence between tectonic environment intensity and the range of lateral pressure coefficients, providing a reliable λ estimation range consistent with regional geological patterns for engineering stages lacking detailed geostress measurement data.

[0043] Using the formula σ h = λ × γ × H calculates the lateral stress value of the foundation, and its derivation is directly derived from the model assumption that the overlying rock strata are simplified as a homogeneous continuous medium. γ × H calculates the vertical stress σ caused by its own weight. vIn this model, the lateral pressure coefficient λ is given a physical meaning that comprehensively characterizes the combined contribution of the Poisson effect and tectonic residual stress in the rock mass, i.e., the ratio of horizontal stress to vertical stress. Therefore, the σ calculated by this formula... h This represents an engineering approximation of the horizontal stress in the original rock acting on the designed orientation of the tunnel under a specific geological background. The principle behind this calculation process is to provide a clear, calculable, and well-defined initial stress state for the entire method, integrating the three factors of burial depth, rock density, and tectonic influence into a single lateral geostress.

[0044] Based on the surrounding rock lithology information, it is determined whether the rock belongs to the preset soft rock category. Then, based on the softening degree determined on-site or in the laboratory, the softening degree-correction coefficient mapping table is consulted to obtain the correction coefficient k. Finally, the formula P = σ is used to determine the corrected rock type. h × (1 + k) calculates the corrected lateral stress value P. A prominent engineering characteristic of soft rock (such as mudstone and shale) is that its strength significantly decreases (softens) over time and due to environmental factors (especially water and wind), and its volume may increase (expansion). This generates additional loads on the support structure far exceeding the initial stress calculation. The softening degree-correction coefficient mapping table essentially condenses the complex physical and chemical degradation process of rock and its mechanical effects into load increment coefficients for different degradation levels through back-analysis of experimental data and engineering cases. The final design lateral pressure P is composed of two superimposed parts: one part is the static reference value σ obtained based on the initial stress field calculation. h The other part covers the additional pressure σ that soft rock may experience due to deterioration during its service life. h ×k. The value of the coefficient k is based on a large amount of empirical experience, which allows the design load to more realistically reflect the most unfavorable state of long-term interaction between the surrounding rock and the support structure in soft rock tunnels. When the rock is determined to be non-soft rock, the process automatically skips this correction (i.e., equivalent to k=0). The principle behind this is that it is acknowledged that the mechanical behavior of hard rock and stable rock masses is mainly elastoplastic during the engineering time, and the time-varying additional load can be ignored.

[0045] Based on the corrected lateral stress value P, the member span L, and the concrete compressive strength f c The formula t = 1.5 × P × L / (2 × f) c The design thickness t of the stress-self-balancing precast component is calculated. The stress state of the precast component (such as an arched slab) under uniformly distributed lateral pressure P is simplified and simulated as a bending member with a span L for bending strength design. The bending moment borne by the component (proportional to the product of P and L) must be less than or equal to the bending capacity of its section (proportional to the material strength f). cIt is proportional to the section modulus, and the section modulus for a rectangular section is proportional to the square of the thickness t. The numerical coefficients 1.5 and 2 in the formula are design coefficients that take into account multiple engineering factors. The principles include: 1) Comprehensive safety factor: used to cover the uncertainty of load calculation (such as variations in geological conditions, empirical correction coefficient k), the dispersion of material strength, the simplification assumptions of the calculation model, and the necessary safety reserve; 2) Design model calibration: simplifying the complex stress state of the actual arch structure into a beam model for calculation, and the coefficient includes the correction for the differences in internal force distribution caused by this simplification; 3) Structural and durability adjustment: ensuring that the calculated theoretical thickness meets the minimum structural requirements, long-term durability, and construction feasibility, so that the results directly serve engineering manufacturing.

[0046] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A method for determining the stability control parameters of roadway surrounding rock, characterized in that, Includes the following steps: The system receives input parameters, including structural stress level identifier, average unit weight γ of overlying strata, tunnel burial depth H, surrounding rock lithology information, component span L, and concrete compressive strength f. c ; Based on the structural stress level identifier, the pre-stored structural stress-lateral pressure coefficient mapping table is queried to determine the corresponding lateral pressure coefficient λ. Using the lateral pressure coefficient λ, the average unit weight γ of the overlying strata, and the tunnel burial depth H, the lateral stress value σ of the foundation is calculated. h = λ × γ × H; Based on the surrounding rock lithology information, determine whether the surrounding rock of the roadway belongs to the preset soft rock category; When the rock is determined to be soft rock, the softening degree-correction coefficient mapping table is consulted based on the softening degree determined on-site or in the laboratory to obtain the mudstone softening and expansion correction coefficient k. The foundation lateral stress value σ h Combined with the mudstone softening and expansion correction factor k, the corrected lateral stress value P = σ is calculated. h × (1 + k); When it is determined that the rock does not belong to the soft rock category, the foundation lateral stress value σ is directly applied. h The corrected lateral stress value P; Based on the corrected lateral stress value P, the span L of the component, and the compressive strength f of the concrete. c The design thickness t of the stress-self-balancing precast component is calculated as: t = 1.5 × P × L / (2 × f) c ); Output the corrected lateral stress value P and the design thickness t.

2. The method for determining the stability control parameters of roadway surrounding rock according to claim 1, characterized in that, The pre-stored structural stress-lateral pressure coefficient mapping table includes: When the tectonic stress level is identified as weak horizontal tectonic stress, the corresponding lateral pressure coefficient λ is 0.3 to 0.5; when the tectonic stress level is identified as a normal sedimentary environment, the corresponding lateral pressure coefficient λ is 0.5 to 1.0; when the tectonic stress level is identified as a strong tectonic stress zone, the corresponding lateral pressure coefficient λ is 1.0 to 2.0; when the tectonic stress level is identified as an extremely strong tectonic zone, the corresponding lateral pressure coefficient λ is greater than 2.

0.

3. The method for determining the stability control parameters of the surrounding rock of a roadway according to claim 1, characterized in that, The softening degree-correction coefficient mapping table includes the following: when the softening degree is weak, the corresponding mudstone softening and expansion correction coefficient k is 0.1 to 0.2; when the softening degree is moderate, the corresponding mudstone softening and expansion correction coefficient k is 0.2 to 0.4; and when the softening degree is strong, the corresponding mudstone softening and expansion correction coefficient k is 0.4 to 0.

7.

4. The method for determining the stability control parameters of the surrounding rock of a roadway according to claim 1, characterized in that, The determination of whether the surrounding rock of the tunnel belongs to the preset soft rock category includes: The surrounding rock lithology information is compared with a preset soft rock lithology list; If the surrounding rock lithology information exists in the soft rock lithology list, it is determined to belong to the soft rock category; If it does not exist, it is determined that it does not belong to the soft rock category.

5. The method for determining the stability control parameters of the surrounding rock of a roadway according to claim 1, characterized in that, After outputting the corrected lateral stress value P and the design thickness t, execute: The corrected lateral stress value P is compared with a preset high stress threshold. If the corrected lateral stress value P is greater than the high stress threshold, then a warning message is generated and output to prompt the adoption of a support scheme with stress self-balancing or reverse bearing structure.

6. A system for confirming control parameters of roadway surrounding rock stability, characterized in that, include: The parameter input module is used to receive input parameters, including structural stress level identifier, average unit weight γ of overlying strata, tunnel burial depth H, surrounding rock lithology information, component span L, and concrete compressive strength f_c. The lateral pressure coefficient mapping module is connected to the parameter input module and is used to query the pre-stored structural stress-lateral pressure coefficient mapping table based on the structural stress level identifier to determine the corresponding lateral pressure coefficient λ. The foundation stress calculation module, connected to the lateral pressure coefficient mapping module and the parameter input module, is used to calculate the foundation lateral stress value σ using the lateral pressure coefficient λ, the average unit weight γ of the overlying strata, and the tunnel burial depth H. h = λ × γ × H; The lithology discrimination module is connected to the parameter input module and is used to determine whether the surrounding rock of the roadway belongs to a preset soft rock category based on the surrounding rock lithology information. The softening correction module, connected to the lithology discrimination module, is used to obtain the mudstone softening and expansion correction coefficient k by querying the softening degree-correction coefficient mapping table based on the softening degree determined on-site or in the laboratory when the mudstone is determined to be of the soft rock category. The integrated stress calculation module, connected to the foundation stress calculation module and the softening correction module, is used to calculate the lateral ground stress value σ of the foundation. h Combined with the mudstone softening and expansion correction factor k, the corrected lateral stress value P = σ is calculated. h × (1 + k); When the lithology discrimination module determines that it does not belong to the soft rock category, the foundation lateral stress value σ is directly calculated. h The corrected lateral stress value P; The component thickness calculation module, connected to the comprehensive stress calculation module and the parameter input module, is used to calculate the thickness based on the corrected lateral stress value P, the component span L, and the concrete compressive strength f. c The design thickness t of the stress-self-balancing precast component is calculated as: t = 1.5 × P × L / (2 × f) c ); The result output module is connected to the comprehensive stress calculation module and the component thickness calculation module, and is used to output the corrected lateral stress value P and the design thickness t.

7. The system for confirming the stability control parameters of roadway surrounding rock according to claim 6, characterized in that, After calculating the corrected lateral stress value P, the integrated stress calculation module also performs the following: The corrected lateral stress value P is compared with a preset high stress threshold. If the corrected lateral stress value P is greater than the high stress threshold, then an early warning message is generated to suggest the use of a support scheme with stress self-balancing or reverse bearing structure. The result output module is also used to output early warning information for the support scheme.

8. The system for confirming the stability control parameters of roadway surrounding rock according to claim 6, characterized in that, The softening correction module is configured to activate and perform the operation of querying the softening degree-correction coefficient mapping table only when it receives a judgment signal from the lithology discrimination module indicating that it belongs to the soft rock category.

9. The system for confirming the stability control parameters of roadway surrounding rock according to claim 6, characterized in that, The lithology discrimination module is specifically as follows: It includes a soft rock lithology list storage unit for storing the preset soft rock lithology list; The lithology discrimination module completes the judgment by comparing the lithology information of the surrounding rock with the soft rock lithology list.

10. The system for confirming the stability control parameters of roadway surrounding rock according to claim 6, characterized in that, After the result output module outputs the design thickness t, it recommends matching standard component specifications for the design thickness t based on the pre-stored component specification library.

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