Tunnel construction risk assessment method and system

Abstract

The application discloses a tunnel construction risk evaluation method and system, relates to the technical field of risk evaluation, and is used for solving the problems of low precision identification and continuous control ability of asymmetric risks of cross tunnels. Before construction, the intersection angle, the geological data of the working face and the pipe shed drilling angle are acquired, the geological smoothness index is calculated, and the direction bias coefficient is generated. In the excavation process, the arch waist displacement difference and mechanical disturbance energy collection are triggered based on the advancing distance, the direction bias coefficient is dynamically corrected, the disturbance propagation trend is identified, after the excavation is completed, the rebound risk state is constructed combined with the rebound data of the sprayed concrete and the track displacement data, the risk accumulation mechanism is triggered, the risk memory factor is further generated based on the track displacement, the directional risk characteristics are formed, and the superimposed risk grade is evaluated and the risk inheritance tunnel is identified according to the directional risk characteristics, so that the identification precision and the whole process control ability of the asymmetric risks in the cross tunnel construction are improved.

Description

Technical Field

[0001] This invention relates to the field of risk assessment technology, and more specifically, to a method and system for risk assessment in tunnel construction. Background Technology

[0002] In the process of urban underground space development and complex transportation engineering construction, the construction of intersecting tunnels has become a common engineering form. Due to the spatial intersection of different tunnels, the stress state of their surrounding rock exhibits obvious asymmetric characteristics. Especially when the intersection angle is small or the geological conditions change significantly, the disturbance of the surrounding rock exhibits directional propagation and superposition effects.

[0003] The existing technology has the following shortcomings: Currently, existing construction processes rely heavily on static geological survey results before construction and monitoring data from a single stage for decentralized risk assessment. Furthermore, the data from each stage are independent of each other and lack correlation. There is a lack of a dynamic assessment and risk transmission characterization mechanism that addresses the coupling of multiple factors such as intersection angles, geological conditions, construction disturbances, and structural responses throughout the entire process. This makes it difficult to identify the directional propagation trend of surrounding rock disturbances and the cumulative and inherited effects of risks between different construction stages and adjacent tunnel structures. Consequently, the ability to accurately identify and continuously control asymmetric risks in intersecting tunnels is reduced. Therefore, a tunnel construction risk assessment method and system are proposed. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a tunnel construction risk assessment method and system. This method addresses the problems mentioned in the background by employing directional bias modeling based on multi-source parameter coupling before construction, a dynamic correction mechanism driven by disturbance response during construction, and a directional risk assessment method that combines risk accumulation and memory after construction.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for assessing tunnel construction risks, comprising the following steps: Step S1: Before receiving the excavation instruction, access the construction design library to retrieve the intersection angle of the intersecting tunnels, collect geological data of the tunnel face and calculate the geological smoothness index, collect the drilling deviation angle of the pipe roof, and match the intersection angle with the geological smoothness index to generate the directional deviation coefficient. Step S2: Excavate the intersecting tunnel and monitor the excavation progress distance. Determine whether to collect the arch waist displacement difference and mechanical disturbance energy based on the excavation progress distance. Correct the directional offset coefficient by combining the arch waist displacement difference and mechanical disturbance energy and analyze the disturbance propagation trend. Step S3: Determine whether the risk accumulation mechanism is triggered based on the disturbance propagation trend. In the risk accumulation mechanism, after the excavation of the intersecting tunnel is completed, collect the rebound data of the shotcrete and the track displacement data, and assess the rebound risk status of the shotcrete based on the rebound data. Step S4: Generate a risk memory factor based on track displacement data, analyze the directional risk characteristics of the intersecting tunnels in conjunction with the rebound risk status analysis, assess the superimposed risk level based on the directional risk characteristics, and identify tunnels with inherited risks.

[0006] In a preferred embodiment, in step S1, before receiving the excavation instruction, the construction design library is accessed to retrieve the design structural parameters of the intersecting tunnel to be constructed, including the intersection angle. The construction design database refers to a structured data storage system established by the design or construction unit before the implementation of tunnel engineering. The intersection angle refers to the spatial angle between the axis direction of the newly built tunnel and the axis direction of the existing tunnel. Geological data of the working face is obtained by deploying ground-penetrating radar at the working face. The geological data of the working face is the echo amplitude value of the surrounding rock corresponding to the sampling location. The average geological index value is obtained by calculating the average value of the geological data of the working face.

[0007] In a preferred embodiment, in step S1, the dispersion of the geological data of the working face at each sampling location relative to the average geological index value is calculated to generate a geological smoothing index. The actual drilling direction angle is read by the guide platform of the pipe roof drilling rig and compared with the designed drilling direction angle. The actual drilling direction angle is subtracted from the designed drilling direction angle to generate the drilling deviation angle. The geological smoothness index is used to match and correct the cross angle. The geological smoothness index is multiplied by the cross angle to generate the effective cross direction angle. The directional offset coefficient is generated based on the effective cross direction angle and drilling deviation angle: ; in, This is the direction offset coefficient. To drill at an angle, The effective cross direction angle.

[0008] In a preferred embodiment, in step S2, during the excavation construction process, the excavation advance distance is obtained in real time through the construction progress recording platform. The excavation advance distance is the axial advance length from the current excavation cycle start point to the current working face position. When the excavation advance distance is greater than or equal to the preset acquisition threshold distance, the disturbance response data acquisition mechanism is triggered. Conversely, the original directional offset coefficient remains unchanged; After the disturbance response data acquisition mechanism is triggered, the displacement of the left and right arch waists is obtained by the automated monitoring equipment deployed at the left and right arch waists of the tunnel, and the displacement of the left and right arch waists is subtracted to obtain the arch waist displacement difference. The power of the tunneling equipment is obtained based on the vibration sensing device, and the mechanical disturbance energy is calculated by integrating the power of the tunneling equipment over a unit of time.

[0009] In a preferred embodiment, in step S2, after obtaining the arch waist displacement difference and mechanical disturbance energy, a direction correction factor is constructed: ; in, This is the direction correction factor. For the difference in arch waist displacement, For mechanical disturbance energy, This refers to the distance the excavation is advanced; The orientation bias coefficient is updated based on the orientation correction factor to obtain the corrected orientation bias coefficient, and the change range of the orientation bias coefficient is calculated. When the change in the directional offset coefficient is greater than 0 and remains greater than 0 for a consecutive preset number of sampling periods, it is determined that the disturbance propagation trend is increasing. When the change in the directional offset coefficient is equal to 0, the disturbance propagation trend is determined to be stable. When the change in the directional offset coefficient is less than 0 and is less than 0 within a preset number of sampling periods, it is determined that the disturbance propagation trend is weakening.

[0010] In a preferred embodiment, in step S3, when the disturbance propagation trend is an enhancing trend, a risk accumulation mechanism is triggered; In the risk accumulation mechanism, the quality of rebound material at each construction section is obtained through the sprayed construction record terminal, and the quality of rebound material is used as the rebound data of sprayed concrete. The change in track displacement corresponding to the shotcrete support structure is obtained by a displacement monitoring device, and the change in track displacement is used as the track displacement data of the shotcrete.

[0011] In a preferred embodiment, in step S3, the mass of shotcrete is obtained through the shotcrete construction recording terminal, and the ratio of the mass of rebound material to the mass of shotcrete is used as the rebound rate of the construction section. When the rebound rate is greater than or equal to the preset rebound risk threshold, the construction section is marked as a high rebound section; otherwise, it is marked as a low rebound section. The ratio of the number of high-rebound sections to the total number of construction sections is used as the proportion of rebound risk. Access the construction quality database to obtain the rebound risk benchmark. If the rebound risk percentage is greater than the rebound risk benchmark, the rebound risk status is high rebound risk status. Conversely, the rebound risk state is a low rebound risk state.

[0012] In a preferred embodiment, in step S4, the absolute value of each track displacement data is taken to obtain each displacement offset, and the standardized processing result after taking the average value of each displacement offset is used as the risk memory factor. When the rebound risk state is high rebound risk state, the rebound adjustment coefficient is set to 2; When the rebound risk state is low, the rebound adjustment coefficient is set to 1. The product of the rebound adjustment coefficient and the risk memory factor is used as the directional risk characteristic of the intersecting tunnel.

[0013] In a preferred embodiment, in step S4, the directional risk characteristics are compared with a preset directional risk threshold to assess the superimposed risk level: When the directional risk characteristics are greater than or equal to the preset directional risk threshold, it is judged as a high superimposed risk level; Conversely, it is judged as a low-risk level. Existing tunnels are categorized and statistically analyzed. When the proportion of monitoring points with high superimposed risk levels corresponding to existing tunnels exceeds the preset inheritance threshold, the existing tunnels are identified as risk inheritance tunnels.

[0014] A tunnel construction risk assessment system includes an bias generation module, a trend analysis module, a cumulative triggering module, and a risk assessment module. The functions of each module are as follows: Before receiving the excavation command, the offset generation module accesses the construction design library to retrieve the intersection angle of the intersecting tunnels, collects geological data of the tunnel face and calculates the geological smoothness index, collects the drilling deviation angle of the pipe roof, matches the intersection angle with the geological smoothness index and generates the directional offset coefficient, and then transmits the directional offset coefficient to the trend analysis module. The trend analysis module excavates the intersecting tunnel and monitors the excavation progress distance. Based on the excavation progress distance, it determines whether to collect the arch waist displacement difference and mechanical disturbance energy. It combines the arch waist displacement difference and mechanical disturbance energy to correct the directional offset coefficient and analyze the directional disturbance trend. The directional disturbance trend is then transmitted to the cumulative trigger module. The cumulative triggering module determines whether to trigger the risk accumulation mechanism based on the directional disturbance trend. In the risk accumulation mechanism, after the excavation of the cross tunnel is completed, the rebound data of the shotcrete and the track displacement data are counted. The rebound risk status of the shotcrete is assessed based on the rebound data, and the track displacement data and rebound risk status are transmitted to the risk assessment module. The risk assessment module generates a risk memory factor based on track displacement data, combines the rebound risk status analysis with the directional risk characteristics of intersecting tunnels, assesses the superimposed risk level based on the directional risk characteristics, and identifies tunnels with inherited risks.

[0015] The technical effects and advantages of this invention are as follows: This invention addresses the issue of directional risk propagation and risk memory residue across construction processes during the construction of intersecting tunnels by constructing a risk assessment method that integrates spatial direction identification and temporal accumulation mechanisms. Before construction, geological data of the intersection angle, tunnel face, and pipe roof drilling deviation are acquired to calculate a geological smoothness index and generate a directional offset coefficient. During excavation, the directional offset coefficient is dynamically corrected based on the arch waist displacement difference triggered by the advance distance and the energy collection of mechanical disturbances, thereby identifying the disturbance propagation trend. After excavation, a rebound risk status is constructed and a risk accumulation mechanism is triggered by combining shotcrete rebound data and track displacement data. Furthermore, a risk memory factor is generated based on track displacement to form directional risk characteristics, which are then used to assess the superimposed risk level and identify tunnels with inherited risks, improving the accuracy of asymmetric risk identification and the overall control capability during the construction of intersecting tunnels. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the implementation of a tunnel construction risk assessment method according to the present invention.

[0017] Figure 2 This is a schematic diagram illustrating the steps of a tunnel construction risk assessment method according to the present invention.

[0018] Figure 3 This is a modular framework diagram of a tunnel construction risk assessment system according to the present invention. Detailed Implementation

[0019] 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.

[0020] This invention addresses the issue of directional risk propagation and risk memory residue across construction processes during the construction of intersecting tunnels by constructing a risk assessment method that integrates spatial direction identification and temporal accumulation mechanisms. Before construction, the method acquires data on the intersection angle, tunnel face geological data, and pipe roof drilling deviation angle to calculate a geological smoothness index and generate a directional offset coefficient. During excavation, the directional offset coefficient is dynamically corrected based on the arch waist displacement difference triggered by the advance distance and the mechanical disturbance energy acquisition, thereby identifying the disturbance propagation trend. After excavation, the method combines shotcrete rebound data and track displacement data to construct a rebound risk status and trigger a risk accumulation mechanism. Furthermore, a risk memory factor is generated based on track displacement to form directional risk characteristics, which are then used to assess the superimposed risk level and identify risk-inherited tunnels.

[0021] Example 1, as Figures 1 to 2 As shown, a method for assessing tunnel construction risks includes the following steps: Step S1: Before receiving the excavation instruction, access the construction design library to retrieve the intersection angle of the intersecting tunnels, collect geological data of the tunnel face and calculate the geological smoothness index, collect the drilling deviation angle of the pipe roof, and match the intersection angle with the geological smoothness index to generate the directional deviation coefficient. Step S2: Excavate the intersecting tunnel and monitor the excavation progress distance. Determine whether to collect the arch waist displacement difference and mechanical disturbance energy based on the excavation progress distance. Correct the directional offset coefficient by combining the arch waist displacement difference and mechanical disturbance energy and analyze the disturbance propagation trend. Step S3: Determine whether the risk accumulation mechanism is triggered based on the disturbance propagation trend. In the risk accumulation mechanism, after the excavation of the intersecting tunnel is completed, collect the rebound data of the shotcrete and the track displacement data, and assess the rebound risk status of the shotcrete based on the rebound data. Step S4: Generate a risk memory factor based on track displacement data, analyze the directional risk characteristics of the intersecting tunnels in conjunction with the rebound risk status analysis, assess the superimposed risk level based on the directional risk characteristics, and identify tunnels with inherited risks.

[0022] The specific implementation is as follows: In step S1, before receiving the excavation command, the initial spatial disturbance direction of the intersecting tunnel is pre-evaluated to generate a directional bias coefficient for directional risk analysis in the subsequent excavation stage.

[0023] Specifically, the first step is to access the construction design database and retrieve the design structural parameters of the intersecting tunnels to be constructed, including the intersection angle. The intersection angle refers to the spatial angle between the axis of the new tunnel and the axis of the existing tunnel, and the centerline angle in the construction design drawings is used as the standard value.

[0024] It should be noted that the construction design database refers to a structured data storage system established by the design or construction unit before the implementation of tunnel engineering. It is used to centrally store design parameters, structural layout information and construction control indicators related to construction.

[0025] The intersection angle reflects the spatial direction relationship between two tunnels. The smaller the value, the more parallel the axes of the two tunnels are, and the higher the possibility that construction disturbances will propagate along the direction of the existing tunnels. The larger the value, the stronger the degree of intersection between the two tunnels, and the more likely the disturbance propagation direction will be laterally dispersed.

[0026] After obtaining the intersection angle, geological data acquisition and processing are performed on the current working face. Geological data of the working face is acquired by ground-penetrating radar deployed on the working face. The geological data of the working face consists of the echo amplitude value of the surrounding rock corresponding to the sampling location. Each sampling location is deployed at equal intervals along the transverse direction of the working face, with the interval being a preset sampling distance.

[0027] It should be noted that ground-penetrating radar refers to geological exploration equipment deployed at or in front of the working face, used to obtain information about the structure of underground media by emitting electromagnetic waves and receiving their reflected signals in the surrounding rock.

[0028] The average geological index value is obtained by calculating the average geological data of the working face. The average geological index value represents the overall average geological level of the working face and reflects the overall mechanical state of the surrounding rock at the current excavation face.

[0029] Calculate the dispersion of the geological data at each sampling location relative to the average geological index value, and generate a geological smoothness index: ; in, Geological smoothness index, This represents the total number of sampling locations. This is the sampling location index value. For geological data of the tunnel face at each sampling location, This represents the average geological index value. This represents the standard deviation of the geological data at the working face.

[0030] The geological smoothness index reflects the continuity and smoothness of the surrounding rock structure at the tunnel face, and its numerical range is [missing value]. The larger the value, the smaller the fluctuation of the geological data at each sampling location, the more uniform and smooth the surrounding rock structure, and the easier it is for construction disturbances to propagate continuously along the predetermined direction; the smaller the value, the stronger the heterogeneity of the surrounding rock, the more obvious the local weak interlayers or fracture zones, and the easier it is for the disturbance direction to deviate.

[0031] After calculating the geological smoothness index, construction data for the pipe roof was collected. Specifically, the actual drilling direction angle was read through the pipe roof drilling rig's guide platform and compared with the designed drilling direction angle. The actual drilling direction angle was subtracted from the designed drilling direction angle to generate the drilling deviation angle. The drilling deviation angle reflects the degree of construction offset of the pre-support structure. The larger its absolute value, the more obvious the deviation of the actual support direction of the pipe roof from the design direction, and the more likely the initial propagation direction of subsequent excavation disturbance in space is to be directionally offset.

[0032] It should be noted that the pipe roof drilling rig guidance platform refers to the attitude detection and direction control system integrated into the pipe roof drilling rig, which is used to obtain the spatial direction information of the drill rod in real time during the drilling process.

[0033] After obtaining the drilling deviation angle, the cross angle is matched and corrected using the geological smoothness index. Specifically, the geological smoothness index is multiplied by the cross angle to generate the effective cross direction angle. The effective cross direction angle reflects the spatial reference angle for risk propagation analysis under the current surrounding rock continuity conditions. When the geological smoothness index is high, the effective cross direction angle is close to the design cross angle; when the geological smoothness index is low, the effective cross direction angle decreases, characterizing the weakening effect of surrounding rock heterogeneity on the propagation direction.

[0034] Furthermore, a directional offset coefficient is generated based on the effective cross direction angle and the drilling deviation angle, with the specific expression as follows: ; in, This is the direction offset coefficient. To drill at an angle, The effective cross direction angle is given; 1 is added to the denominator to avoid denominator anomalies when the cross angle is close to zero.

[0035] The directional offset coefficient reflects the degree of deviation of the initial disturbance from the design intersection direction. The larger the value, the easier it is for the pipe roof deviation to induce the risk to propagate in a directional manner to the existing tunnel side under the current surrounding rock conditions. The smaller the value, the higher the consistency between the initial disturbance direction and the design direction, and the better the stability of the subsequent risk propagation direction.

[0036] Through the above processing, the initial directional risk benchmark for the intersecting tunnel is established before excavation, providing unified quantitative input parameters for directional disturbance trend analysis in subsequent steps.

[0037] In step S2, after the directional offset coefficient is generated, the excavation construction of the intersecting tunnel is carried out and the disturbance propagation monitoring and correction process is carried out simultaneously to realize the dynamic updating of the directional offset coefficient and the identification of the disturbance propagation trend.

[0038] Specifically, during the excavation process, the excavation progress distance is obtained in real time through the construction progress recording platform. The excavation progress distance is the axial advancement length from the current excavation cycle start point to the current working face position, reflecting the extent of the expansion of construction disturbance in space. The larger the value, the wider the scope of the construction disturbance and the longer the potential propagation path.

[0039] It should be noted that the construction progress recording platform refers to a digital management system used to record the execution status of each process during tunnel construction.

[0040] A preset acquisition threshold distance is set. When the excavation advance distance is greater than or equal to the preset acquisition threshold distance, the disturbance response data acquisition mechanism is triggered; when the excavation advance distance is less than the preset acquisition threshold distance, the original directional offset coefficient remains unchanged.

[0041] It should be noted that the preset acquisition threshold distance is determined based on the step length or single-cycle advance, in order to ensure that the disturbance data has a sufficient cumulative effect before being included in the analysis.

[0042] After the disturbance response data acquisition mechanism is triggered, the displacements of the left and right arch waists are acquired by automated monitoring equipment deployed at the left and right arch waists of the tunnel. The left and right arch waist displacements are then subtracted to obtain the arch waist displacement difference. The arch waist displacement difference reflects the degree of asymmetric deformation of the tunnel cross section in the transverse direction. The larger the absolute value, the more uneven the stress distribution of the surrounding rock or support structure, and the more obvious the directional bias of the disturbance propagation in space. Its sign reflects the direction of disturbance offset. When the arch waist displacement difference is greater than 0, it indicates that the deformation on the left side is greater than that on the right side. When the arch waist displacement difference is less than 0, it indicates that the deformation on the right side is greater than that on the left side.

[0043] Simultaneously, mechanical disturbance energy is acquired through vibration sensing devices. Specifically, the power of the tunneling equipment is obtained based on the vibration sensing devices, and the mechanical disturbance energy is calculated by integrating the power of the tunneling equipment per unit time. The mechanical disturbance energy reflects the energy level input to the surrounding rock during construction; the larger the value, the higher the disturbance intensity to the surrounding rock and the stronger the disturbance propagation ability.

[0044] It should be noted that automated monitoring equipment refers to displacement monitoring devices installed at key locations in the tunnel structure (such as the arch crown, arch waist, and sidewalls) to collect structural deformation data in real time; vibration sensing devices refer to dynamic response detection devices installed on construction equipment or the surface of surrounding rock to collect vibration signals or equipment operating power signals generated during construction.

[0045] After obtaining the arch waist displacement difference and mechanical disturbance energy, a direction correction factor is constructed, the specific expression of which is as follows: ; in, This is the direction correction factor. For the difference in arch waist displacement, For mechanical disturbance energy, This represents the excavation advance distance; adding 1 to the denominator is to prevent numerical anomalies caused by excessively small advance distances.

[0046] The directional correction factor reflects the degree of directional reinforcement of the disturbance under the combined effect of asymmetric deformation and energy input during the current propulsion phase. The larger the value, the more obvious the tendency of the disturbance to propagate along a certain side.

[0047] The orientation bias coefficients are further updated based on the orientation correction factor to obtain the corrected orientation bias coefficients: ; in, This is the corrected direction offset coefficient. This is the direction offset coefficient. This is the direction correction factor.

[0048] The corrected directional bias coefficient reflects the degree of deviation of the risk propagation direction from the initial prediction under the actual excavation disturbance. The larger the value, the more significant the directional amplification of the disturbance at the current stage.

[0049] After updating the directional offset coefficient, the perturbation propagation trend is analyzed based on the changing trend. Specifically, the magnitude of the change in the directional offset coefficient is calculated: ; in, This represents the magnitude of the change in the directional offset coefficient. This is the corrected direction offset coefficient. This is the direction offset coefficient.

[0050] When the change in the directional offset coefficient is greater than 0 and is greater than 0 within a consecutive preset number of sampling periods, that is, when it increases monotonically within multiple sampling periods, it is determined that the disturbance propagation trend is strengthening. When the change in the directional offset coefficient is equal to 0, it is determined that the disturbance propagation trend tends to be stable. When the change in the directional offset coefficient is less than 0 and is less than 0 within a preset number of sampling periods, that is, when it decreases monotonically within multiple sampling periods, it is determined that the disturbance propagation trend is weakening.

[0051] The disturbance propagation trend is used to characterize the evolution of the risk propagation direction during construction, providing a basis for determining the triggering of risk accumulation mechanisms in subsequent steps.

[0052] In step S3, when the disturbance propagation trend is an enhancing trend, the risk accumulation mechanism is triggered to collect and evaluate the shotcrete rebound data and track displacement data, thereby improving the continuity and accuracy of risk identification in cross tunnel construction. In the risk accumulation mechanism, after the excavation of the cross tunnel is completed, the rebound material mass of each construction section is obtained through the shotcrete construction record terminal. The rebound material mass refers to the total mass of concrete material that does not adhere to the surrounding rock surface and rebounds and falls back during the shotcrete construction process. The rebound material mass is used as the rebound data of shotcrete to reflect the degree of material loss and the effectiveness of shotcrete adhesion during the construction process. The larger the rebound material mass value, the lower the adhesion efficiency of shotcrete and the weaker the ability to form surface support of surrounding rock. The change in track displacement corresponding to the shotcrete support structure is obtained by a displacement monitoring device. The change in track displacement refers to the difference in displacement between the baseline measurement time before the excavation of the cross tunnel is completed and the target measurement time after the excavation of the cross tunnel is completed by the displacement monitoring point located at the position of the tunnel track structure. The reference measurement time is the time node for initial displacement measurement of the existing tunnel track structure before the start of the excavation of the cross tunnel. The target measurement time is the time node for displacement re-measurement within a preset time interval after the excavation of the cross tunnel is completed. The change in track displacement is obtained by subtracting the displacement measurement value corresponding to the reference measurement time from the displacement measurement value corresponding to the target measurement time. The displacement monitoring points can be evenly distributed along the existing tunnel track structure in the cross-affected section at preset intervals.

[0053] Using the change in track displacement as track displacement data for shotcrete, it reflects the overall response degree after the disturbance from the construction of the cross tunnel is transmitted to the existing structure through the surrounding rock and support structure. The mass of shotcrete applied is obtained through the shotcrete construction recording terminal, and the ratio of the mass of rebound material to the mass of shotcrete applied is used as the rebound rate of the construction section. The rebound rate of each construction section is compared with the preset rebound risk threshold. When the rebound rate is greater than or equal to the preset rebound risk threshold, the construction section is marked as a high rebound section; otherwise, it is marked as a low rebound section. The ratio of the number of high-rebound sections to the total number of construction sections is used as the proportion of rebound risk. Access the construction quality database to obtain the rebound risk benchmark. The rebound risk benchmark is obtained by classifying and statistically analyzing the proportion of sections in historical construction sections whose rebound rate exceeds the control requirements and dividing them into intervals. The rebound risk percentage is compared with the rebound risk benchmark to assess the rebound risk status of shotcrete: If the rebound risk percentage is greater than the rebound risk benchmark, then the rebound risk status is a high rebound risk status. Conversely, the rebound risk state is a low rebound risk state; A high rebound risk condition reflects a high degree of adhesion loss of shotcrete and a weak buffering capacity of the support structure against construction disturbances; a low rebound risk condition reflects a good adhesion effect of shotcrete and a strong absorption capacity of the support structure against construction disturbances.

[0054] It should be noted that the spraying construction record terminal is a digital recording device that collects and stores material delivery data in real time during the spraying operation; the displacement monitoring device is a displacement detection device installed at the tunnel track structure to obtain displacement measurement values; the preset rebound risk threshold can be set according to the rebound risk ratio range corresponding to the rebound rate exceeding the quality control requirements under different construction conditions; the construction quality database is a structured database used to store various quality inspection data and historical construction records during the construction of intersecting tunnels.

[0055] In step S4, the absolute value of each track displacement data is taken to obtain each displacement offset, and the standardized result after averaging each displacement offset is used as the risk memory factor. The risk memory factor reflects the cumulative residual degree of construction disturbance in the existing tunnel track structure. The larger the value, the more obvious the overall track displacement change, and the stronger the residual effect of the previous construction disturbance in the structure. When the rebound risk state is high rebound risk state, the rebound adjustment coefficient is set to 2; When the rebound risk state is low, the rebound adjustment coefficient is set to 1. The product of the rebound adjustment coefficient and the risk memory factor is used as the directional risk characteristic of the cross tunnel. The larger the value of the directional risk characteristic, the more obvious the disturbance residue and the weaker the support absorption capacity, and the higher the possibility of the risk continuing along the direction of the existing structure. The level of superimposed risk is assessed by comparing the targeted risk characteristics with a preset targeted risk threshold. When the directional risk characteristics are greater than or equal to the preset directional risk threshold, it is judged as a high superimposed risk level; Conversely, it is judged as a low-risk level. The existing tunnels to which each displacement monitoring point belongs are classified and statistically analyzed. When the proportion of monitoring points with high superimposed risk levels among the displacement monitoring points corresponding to the existing tunnel is greater than the preset inheritance threshold, the existing tunnel is identified as a risk inheritance tunnel.

[0056] It should be explained that the standardization processing methods include, but are not limited to, standard linear transformation based on interval scaling, Z-Score standardization based on statistics, or normalization based on nonlinear mapping functions. The application methods of standardization processing will not be elaborated here. The preset directional risk threshold can be set according to the value range of directional risk characteristics corresponding to the occurrence of track displacement exceeding the limit or abnormal structural deformation in existing projects. The preset inheritance threshold can be set by screening sections with continuous displacement residual phenomena in historical construction data and statistically calculating the average value of their directional risk characteristics over multiple continuous monitoring periods.

[0057] Example 2, as Figure 3As shown, a tunnel construction risk assessment system includes an bias generation module, a trend analysis module, a cumulative triggering module, and a risk assessment module. The functions of each module are as follows: Before receiving the excavation command, the offset generation module accesses the construction design library to retrieve the intersection angle of the intersecting tunnels, collects geological data of the tunnel face and calculates the geological smoothness index, collects the drilling deviation angle of the pipe roof, matches the intersection angle with the geological smoothness index and generates the directional offset coefficient, and then transmits the directional offset coefficient to the trend analysis module. The trend analysis module excavates the intersecting tunnel and monitors the excavation progress distance. Based on the excavation progress distance, it determines whether to collect the arch waist displacement difference and mechanical disturbance energy. It combines the arch waist displacement difference and mechanical disturbance energy to correct the directional offset coefficient and analyze the directional disturbance trend. The directional disturbance trend is then transmitted to the cumulative trigger module. The cumulative triggering module determines whether to trigger the risk accumulation mechanism based on the directional disturbance trend. In the risk accumulation mechanism, after the excavation of the cross tunnel is completed, the rebound data of the shotcrete and the track displacement data are counted. The rebound risk status of the shotcrete is assessed based on the rebound data, and the track displacement data and rebound risk status are transmitted to the risk assessment module. The risk assessment module generates a risk memory factor based on track displacement data, combines the rebound risk status analysis with the directional risk characteristics of intersecting tunnels, assesses the superimposed risk level based on the directional risk characteristics, and identifies tunnels with inherited risks.

[0058] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0059] Finally, it should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0060] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] In this document, the singular forms “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that terms such as “comprising / including” or “having” specify the presence of the stated features, integrals, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integrals, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0062] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0063] The above description of the disclosed embodiments will enable those skilled in the art to make or use various modifications to these embodiments. It will be readily apparent to those skilled in the art that the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for assessing tunnel construction risks, characterized in that: Includes the following steps: Step S1: Before receiving the excavation instruction, access the construction design library to retrieve the intersection angle of the intersecting tunnels, collect geological data of the tunnel face and calculate the geological smoothness index, collect the drilling deviation angle of the pipe roof, and match the intersection angle with the geological smoothness index to generate the directional deviation coefficient. Step S2: Excavate the intersecting tunnel and monitor the excavation progress distance. Determine whether to collect the arch waist displacement difference and mechanical disturbance energy based on the excavation progress distance. Correct the directional offset coefficient by combining the arch waist displacement difference and mechanical disturbance energy and analyze the disturbance propagation trend. Step S3: Determine whether the risk accumulation mechanism is triggered based on the disturbance propagation trend. In the risk accumulation mechanism, after the excavation of the intersecting tunnel is completed, collect the rebound data of the shotcrete and the track displacement data, and assess the rebound risk status of the shotcrete based on the rebound data. Step S4: Generate a risk memory factor based on track displacement data, analyze the directional risk characteristics of the intersecting tunnels in conjunction with the rebound risk status analysis, assess the superimposed risk level based on the directional risk characteristics, and identify tunnels with inherited risks.

2. The tunnel construction risk assessment method according to claim 1, characterized in that: In step S1, before receiving the excavation instruction, the construction design library is accessed to retrieve the design structural parameters of the intersecting tunnel to be constructed, including the intersection angle. The construction design database refers to a structured data storage system established by the design or construction unit before the implementation of tunnel engineering. The intersection angle refers to the spatial angle between the axis direction of the newly built tunnel and the axis direction of the existing tunnel. Geological data of the working face is obtained by deploying ground-penetrating radar at the working face. The geological data of the working face is the echo amplitude value of the surrounding rock corresponding to the sampling location. The average geological index value is obtained by calculating the average value of the geological data of the working face.

3. The tunnel construction risk assessment method according to claim 2, characterized in that: In step S1, the dispersion of the geological data of the tunnel face at each sampling location relative to the average geological index value is calculated, and a geological smoothing index is generated. The actual drilling direction angle is read by the guide platform of the pipe roof drilling rig and compared with the designed drilling direction angle. The actual drilling direction angle is subtracted from the designed drilling direction angle to generate the drilling deviation angle. The geological smoothness index is used to match and correct the cross angle. The geological smoothness index is multiplied by the cross angle to generate the effective cross direction angle. The directional offset coefficient is generated based on the effective cross direction angle and drilling deviation angle: ; in, This is the direction offset coefficient. To drill at an angle, The effective cross direction angle.

4. The tunnel construction risk assessment method according to claim 1, characterized in that: In step S2, during the excavation process, the excavation progress distance is obtained in real time through the construction progress recording platform. The excavation progress distance is the axial advancement length from the current excavation cycle start point to the current working face position. When the excavation advance distance is greater than or equal to the preset acquisition threshold distance, the disturbance response data acquisition mechanism is triggered. Conversely, the original directional offset coefficient remains unchanged; After the disturbance response data acquisition mechanism is triggered, the displacement of the left and right arch waists is obtained by the automated monitoring equipment deployed at the left and right arch waists of the tunnel, and the displacement of the left and right arch waists is subtracted to obtain the arch waist displacement difference. The power of the tunneling equipment is obtained based on the vibration sensing device, and the mechanical disturbance energy is calculated by integrating the power of the tunneling equipment over a unit of time.

5. The tunnel construction risk assessment method according to claim 4, characterized in that: In step S2, after obtaining the arch waist displacement difference and mechanical disturbance energy, a direction correction factor is constructed: ; in, This is the direction correction factor. For the difference in arch waist displacement, For mechanical disturbance energy, This refers to the distance the excavation is advanced; The orientation bias coefficient is updated based on the orientation correction factor to obtain the corrected orientation bias coefficient, and the change range of the orientation bias coefficient is calculated. When the change in the directional offset coefficient is greater than 0 and remains greater than 0 for a consecutive preset number of sampling periods, it is determined that the disturbance propagation trend is increasing. When the change in the directional offset coefficient is equal to 0, the disturbance propagation trend is determined to be stable. When the change in the directional offset coefficient is less than 0 and is less than 0 within a preset number of sampling periods, it is determined that the disturbance propagation trend is weakening.

6. The tunnel construction risk assessment method according to claim 1, characterized in that: In step S3, when the disturbance propagation trend is an enhancing trend, the risk accumulation mechanism is triggered; In the risk accumulation mechanism, the quality of rebound material at each construction section is obtained through the sprayed construction record terminal, and the quality of rebound material is used as the rebound data of sprayed concrete. The change in track displacement corresponding to the shotcrete support structure is obtained by a displacement monitoring device, and the change in track displacement is used as the track displacement data of the shotcrete.

7. The tunnel construction risk assessment method according to claim 6, characterized in that: In step S3, the mass of shotcrete is obtained through the shotcrete construction record terminal, and the ratio of the mass of rebound material to the mass of shotcrete is used as the rebound rate of the construction section. When the rebound rate is greater than or equal to the preset rebound risk threshold, the construction section is marked as a high rebound section; otherwise, it is marked as a low rebound section. The ratio of the number of high-rebound sections to the total number of construction sections is used as the proportion of rebound risk. Access the construction quality database to obtain the rebound risk benchmark. If the rebound risk percentage is greater than the rebound risk benchmark, the rebound risk status is high rebound risk status. Conversely, the rebound risk state is a low rebound risk state.

8. The tunnel construction risk assessment method according to claim 1, characterized in that: In step S4, the absolute value of each track displacement data is taken to obtain each displacement offset, and the standardized result after averaging each displacement offset is used as the risk memory factor. When the rebound risk state is high rebound risk state, the rebound adjustment coefficient is set to 2; When the rebound risk state is low, the rebound adjustment coefficient is set to 1. The product of the rebound adjustment coefficient and the risk memory factor is used as the directional risk characteristic of the intersecting tunnel.

9. The tunnel construction risk assessment method according to claim 8, characterized in that: In step S4, the directional risk characteristics are compared with a preset directional risk threshold to assess the superimposed risk level: When the directional risk characteristics are greater than or equal to the preset directional risk threshold, it is judged as a high superimposed risk level; Conversely, it is judged as a low-risk level. Existing tunnels are categorized and statistically analyzed. When the proportion of monitoring points with high superimposed risk levels corresponding to existing tunnels exceeds the preset inheritance threshold, the existing tunnels are identified as risk inheritance tunnels.

10. A tunnel construction risk assessment system, used to implement the tunnel construction risk assessment method according to any one of claims 1-9, characterized in that: It includes a bias generation module, a trend analysis module, a cumulative triggering module, and a risk assessment module. The functions of each module are as follows: Before receiving the excavation command, the offset generation module accesses the construction design library to retrieve the intersection angle of the intersecting tunnels, collects geological data of the tunnel face and calculates the geological smoothness index, collects the drilling deviation angle of the pipe roof, matches the intersection angle with the geological smoothness index and generates the directional offset coefficient, and then transmits the directional offset coefficient to the trend analysis module. The trend analysis module excavates the intersecting tunnel and monitors the excavation progress distance. Based on the excavation progress distance, it determines whether to collect the arch waist displacement difference and mechanical disturbance energy. It combines the arch waist displacement difference and mechanical disturbance energy to correct the directional offset coefficient and analyze the directional disturbance trend. The directional disturbance trend is then transmitted to the cumulative trigger module. The cumulative triggering module determines whether to trigger the risk accumulation mechanism based on the directional disturbance trend. In the risk accumulation mechanism, after the excavation of the cross tunnel is completed, the rebound data of the shotcrete and the track displacement data are counted. The rebound risk status of the shotcrete is assessed based on the rebound data, and the track displacement data and rebound risk status are transmitted to the risk assessment module. The risk assessment module generates a risk memory factor based on track displacement data, combines the rebound risk status analysis with the directional risk characteristics of intersecting tunnels, assesses the superimposed risk level based on the directional risk characteristics, and identifies tunnels with inherited risks.

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