Settlement calculation, risk assessment and dynamic control method for shield under-crossing building
By combining the Mindlin solution and the Segaseta pooling method in the calculation model, the problem of insufficient scientific rigor in settlement calculation and risk assessment during shield tunneling under buildings was solved. This enabled high-precision settlement calculation and personalized risk assessment, dynamic adjustment of construction parameters, and avoidance of safety and economic risks during construction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-07
- Publication Date
- 2026-04-07
AI Technical Summary
Existing technologies lack a progressive assessment process during the tunnel boring machine (TBM) tunneling under buildings, failing to effectively quantify structural differences in buildings. This results in a lack of scientific risk assessment and delayed control decisions, leading to increased construction costs or safety risks.
A calculation model combining the Mindlin solution and the Segaseta pooling method was adopted to comprehensively consider the additional thrust at the tunnel face, the amount of excavated soil, the friction of the cutterhead, the shield tail gap, the synchronous grouting pressure, and the friction of the shield shell to perform settlement calculation and risk assessment, and to achieve dynamic control by back-calculating construction parameters.
It enables high-precision calculation and personalized risk assessment of settlement of old buildings, dynamically adjusts construction parameters, avoids ineffective costs and safety hazards, shortens response time, and reduces irreversible damage.
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Abstract
Description
Technical Field
[0001] This invention relates to a method for calculating, assessing the risk of, and dynamically controlling the settlement of tunnel boring machines (TBMs) passing under buildings. It is applicable to the field of civil engineering. Background Technology
[0002] With the rapid development of urban underground space, subway shield tunnels frequently traverse densely built-up urban areas, making shield tunneling under buildings a common occurrence during construction. Shield tunneling can cause ground disturbance, soil loss, and surface settlement, leading to uneven settlement, cracks, and even structural damage to surface buildings. Therefore, it is not only necessary to accurately assess the risks to buildings during shield tunneling, but also to establish a coordinated "risk assessment-construction control" mechanism to fundamentally ensure the safety and economy of the project. This is the core need that urgently needs to be addressed in current shield tunneling projects.
[0003] Currently, some patents and technical solutions have attempted to address the risks associated with tunnel boring machines (TBMs) passing under buildings by focusing on structural support and construction control. However, existing technical solutions have the following limitations: First, the assessment is fragmented, focusing only on passive protection (such as support and grouting) or only on a single construction stage, lacking a progressive assessment process of "surface settlement screening → sensitivity classification → structural damage quantification". Second, the lack of mechanical support and the absence of mechanical analysis of the building during the assessment process meant that risk assessment relied heavily on experience rather than quantitative analysis. Third, the assessment and control are disconnected. The mapping relationship between "risk level → construction parameter inversion" has not been established. It is impossible to guide real-time parameter adjustment through assessment results, nor can the accuracy of assessment be verified through control effects. As a result, risk control decisions lack scientific rigor and foresight.
[0004] If the risk level of a building cannot be clearly defined through phased assessments before construction, and construction parameters cannot be dynamically adjusted based on the assessment results during construction, only extremely conservative construction plans (such as full-range grouting and low-speed tunneling) can be adopted, leading to soaring costs, extended construction periods, or actual damage to the building due to insufficient control, bringing greater safety and economic risks to the contractor.
[0005] Analysis revealed that the aforementioned deficiencies in existing technologies stem from the following technical challenges: First, surface settlement calculations are largely based on empirical methods, neglecting key roles such as cutterhead friction and synchronous grouting coupling; second, building damage assessments use uniform thresholds, failing to quantify the differences in deformation resistance of older buildings due to structural type and construction time, and lacking mechanical model support; third, adjustments to construction parameters rely on empirical trial and error, lacking quantitative control methods, resulting in a delayed response. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide a method for calculating, assessing the risk of, and dynamically controlling the settlement of shield tunnels passing under buildings, in view of the above-mentioned problems.
[0007] The technical solution adopted in this invention is: a method for calculating the settlement of a shield tunneling structure, comprising: The relative position of the target building location and the tunnel boring machine (TBM) is obtained, as well as the operating parameters of the TBM, including the additional thrust at the tunnel face, the amount of excavated soil, the friction of the cutterhead, the tail clearance, the synchronous grouting pressure at the tail, and the friction of the shield shell. Based on the relative position of the target building location and the tunnel boring machine, as well as the tunnel boring machine's operating parameters and the vertical displacement calculation model corresponding to each operating parameter, the vertical displacement at the target building location caused by each operating parameter is determined. Based on the vertical displacement caused by various operating parameters, the total settlement at the target building location caused by shield tunneling is determined.
[0008] The calculation model for the vertical displacement corresponding to the additional thrust at the working face, the frictional force of the cutterhead, the synchronous grouting pressure at the shield tail, and the frictional force of the shield shell is derived and solved using the Mindlin method.
[0009] The calculation model for the vertical displacement corresponding to the excavated soil volume and the shield tail gap is derived using the Segaseta sink method.
[0010] A method for risk assessment of shield tunneling under buildings includes: The settlement calculation method described above is used to determine the total settlement at the target building location caused by the tunnel boring machine construction. The risk of the tunnel boring machine passing under the building is assessed based on the total settlement at the target building location.
[0011] The assessment of the risk of the tunnel boring machine (TBM) passing under the building, based on the total settlement at the target building location, includes: Obtain key structural indicators of the target building, including the overall condition of the building, the type of foundation, the type of building structure, and the construction time. Based on the key structural indicators of the target building, determine the building score corresponding to each key indicator of the target building; Based on the building scores corresponding to each key indicator, the total building score corresponding to the target building is determined, and the vulnerability correction coefficient of the target building is determined based on the total building score. Based on the vulnerability correction factor and the total settlement at the target building location, the bending strain and angular strain of the target building are calculated. Calculate the horizontal strain of the target building based on the difference in horizontal displacement between its two ends; The risk of the shield tunnel passing under the building is assessed based on the horizontal strain, bending strain, and angular strain of the target building.
[0012] The determination of the vulnerability correction factor for the target building based on the overall building score includes: Based on the total building score corresponding to the target building, the vulnerability correction factor of the target building is determined by referring to the building vulnerability correction factor table.
[0013] The vulnerability correction factor includes the moment of inertia correction factor and the elastic modulus correction factor.
[0014] The assessment of the risks of shield tunneling under a building, based on the horizontal strain, bending strain, and angular strain of the target building, includes: The first superimposed strain is obtained by superimposing the horizontal strain onto the bending strain; the second superimposed strain is obtained by superimposing the horizontal strain onto the angular strain. The maximum value between the first superimposed strain and the second superimposed strain is taken, and the risk level of the shield tunneling under the building is determined based on the maximum value and the preset risk classification standard.
[0015] A method for dynamic control of shield tunneling under buildings includes: S310. Obtain the real-time settlement value of the target building, as well as the relative position of the target building location and the tunnel boring machine; S320. When the real-time settlement value exceeds the settlement warning value, the vertical displacement adjustment value is determined based on the difference between the real-time settlement value and the settlement warning value. Then, combined with the vertical displacement calculation model corresponding to the relative position and each operating parameter, the motion parameter adjustment value is calculated in reverse, and the operating parameters of the tunnel boring machine are adjusted.
[0016] Step S320 includes: S321. Based on the vertical displacement adjustment value, combined with the vertical displacement calculation model corresponding to the relative position and the additional thrust at the tunnel face, the adjustment value of the additional thrust at the tunnel face is calculated in reverse, and then the additional thrust at the tunnel face of the shield machine is adjusted. S322. Obtain the real-time settlement value of the target building again. If the real-time settlement value still exceeds the settlement warning value, determine the vertical displacement adjustment value based on the difference between the real-time settlement value and the settlement warning value. S323. Based on the vertical displacement adjustment value determined in step S322, and combined with the vertical displacement calculation model corresponding to the relative position and the amount of excavated soil, the adjustment value of the amount of excavated soil is calculated in reverse, and then the amount of excavated soil of the tunnel boring machine is adjusted. S324. Obtain the real-time settlement value of the target building again. If the real-time settlement value still exceeds the settlement warning value, determine the vertical displacement adjustment value based on the difference between the real-time settlement value and the settlement warning value. S325. Based on the vertical displacement adjustment value determined in step S324, and combined with the vertical displacement calculation model corresponding to the relative position and the synchronous grouting pressure at the shield tail, the excavation soil volume adjustment value is calculated in reverse, and then the synchronous grouting pressure at the shield tail of the tunnel boring machine is adjusted.
[0017] The beneficial effects of this invention are as follows: For shield tunneling under old buildings, the surface settlement calculation comprehensively considers six core construction factors: additional thrust at the tunnel face, excavated soil, cutterhead friction, shield tail gap, synchronous grouting pressure, and shield shell friction. A hybrid analytical strategy of "Mindlin solution + Segaseta summation method" is adopted (Mindlin solution solves for displacements caused by additional thrust at the tunnel face, cutterhead friction, synchronous grouting pressure, and shield shell friction; Segaseta summation method solves for displacements caused by excavated soil and shield tail gap), and the total settlement is finally obtained by superimposing the displacements. This invention expands the dimensions of settlement calculation to "six core factors," better aligning with the actual mechanical behavior of shield tunneling. By solving for each source, it avoids the accuracy loss of a single method, enabling precise calculation of settlement distribution at any location on the ground surface. It is particularly suitable for the "small-scale, high-precision" settlement requirements under old buildings.
[0018] This invention constructs a scoring system based on four core indicators: "overall building condition, foundation type, building structure type, and construction time." The system categorizes buildings into low, medium, and high vulnerability levels by summing the scores, and correspondingly sets a moment of inertia correction coefficient k. I With the elastic modulus correction factor k E This invention simplifies the building into a deep beam model, and combines the surface settlement value calculated before construction to calculate the corrected moment of inertia I' and the corrected elastic modulus E'. It further solves for the superposition of bending strain, angular strain, and horizontal strain, and determines the damage level by comparing it with a risk threshold. This invention overcomes the limitations of existing technologies that ignore individual differences in buildings (such as the sensitivity differences between old masonry and reinforced concrete), quantifies the structural deformation resistance of different buildings, and upgrades damage assessment from "generalized" to "personalized." It avoids over-reinforcing low-sensitivity buildings or under-assessing high-sensitivity buildings, providing a clear basis for pre-construction reinforcement decisions, avoiding both ineffective cost investment and safety hazards.
[0019] During the construction phase, this invention, based on the vertical displacement calculation model system corresponding to each operating parameter, derives the linear analytical relationship between settlement and parameters through back-calculation. Target parameters are calculated in reverse order of priority: additional thrust at the tunnel face → excavation soil removal rate → synchronous grouting pressure at the shield tail. This achieves an immediate response of "monitoring data → parameter correction," dynamically controlling settlement within a safe range. It overcomes the shortcomings of traditional construction parameter adjustments, which rely on "experience-based trial and error and delayed response." The linear inversion formula can directly calculate target parameters through real-time monitoring of settlement values, eliminating the need for experience and reducing response time to the "minute level," thus avoiding continuous damage when settlement exceeds limits. Furthermore, this method grasps the core of settlement control in shield tunneling, addressing the issue from the "source" rather than "post-construction remediation," fundamentally reducing initial settlement values and preventing irreversible damage to old buildings caused by persistent excessive settlement. Attached Figure Description
[0020] Figure 1 This is a flowchart illustrating the method for calculating settlement when a shield tunnel passes under a building, as shown in the embodiment.
[0021] Figure 2 This is a flowchart of the risk assessment method for shield tunneling under buildings in the embodiment.
[0022] Figure 3 This is a flowchart of the dynamic control method for shield tunneling under buildings in the embodiment. Detailed Implementation
[0023] Example 1: Before tunneling under a building, the first stage of the work involves calculating and analyzing the potential surface settlement caused by the tunneling operation. For example... Figure 1 As shown, the method for calculating the settlement of a shield tunneling structure includes: S110. Obtain the relative position of the target building location and the tunnel boring machine, as well as the operating parameter values of the tunnel boring machine.
[0024] In this embodiment, the location information of the target building and the location information of the center of the tunnel boring machine cutterhead are obtained, and the relative position of the target building and the tunnel boring machine is determined based on the location information of the target building and the location information of the center of the cutterhead.
[0025] In this embodiment, when calculating surface settlement, six major operating parameters of the tunnel boring machine are comprehensively considered: additional thrust at the tunnel face, excavated soil volume, cutterhead friction, shield tail gap, shield tail synchronous grouting pressure, and shield shell friction.
[0026] S120. Based on the relative position of the target building location and the tunnel boring machine, as well as the tunnel boring machine's operating parameters and the vertical displacement calculation model corresponding to each operating parameter, determine the vertical displacement at the target building location caused by each operating parameter.
[0027] Surface settlement is the result of multiple factors acting together during shield tunneling. Therefore, Mindlin solution and sink method were used to calculate surface settlement caused by shield tunneling under different operating parameters.
[0028] ① Calculation model of vertical displacement corresponding to additional thrust at the tunnel face The support pressure at the tunnel boring machine (TBM) excavation face provides pressure in front of the excavator to balance the earth pressure ahead. The TBM excavation face is designed with openings to facilitate the entry of cut soil into the soil chamber, where it is then transported away. The ratio of the opening area to the total cutterhead surface area is called the opening ratio. During the tunneling process of a shield tunnel, the presence of the cutterhead opening causes the stress conditions of the soil in front of the excavation face to alternate between two conditions as the cutterhead rotates: (1) The cutterhead is supported by the cutterhead surface, and the cutterhead is supported by the jack behind it. At this time, the soil is subjected to the thrust from the cutterhead surface. When the thrust is greater than or less than the in-situ earth pressure, it will cause the surrounding strata to deform. (2) When the soil is located at the opening of the cutterhead, the stratum is supported by the soil inside the opening and flows into the soil chamber as the cutting progresses. If too much soil is discharged during the discharge process, additional stratum settlement will also occur.
[0029] In summary, considering the complex mechanism of shield tunnel face advancement, it is necessary to separately consider the two factors of cutterhead support force and excavated soil when analyzing the impact of the face on the settlement of the surrounding strata. The Mindlin method is used to derive the solution for the strata deformation caused by the cutterhead thrust; the Segaseta source method is used to derive the solution for the impact of excavated soil at the opening.
[0030] It should be noted that when using the Mindlin solution, the actual area of the soil supported by the cutterhead is considered. The area of the entire cutter head is times the total area, therefore, the integral is performed over the entire cutter head and then multiplied by... To avoid redundant considerations, the soil excavation at the opening is considered using the soil loss rate, which can be directly used for derivation and calculation. Finally, the two factors are superimposed to obtain the impact of the excavation face on the strata.
[0031] Based on the above discussion, the difference between the cutterhead support pressure provided by the jacks and the in-situ soil and water pressure at the excavation face is defined as the additional thrust of the shield tunneling machine, under which the soil undergoes a certain deformation. Consider any infinitesimal element on the surface of action. The concentrated force it experiences is .
[0032] Based on the Mindlin solution, the uniformly distributed additional thrust q at the front of the shield tunnel causes a change in the coordinate system. midpoint Vertical displacement for: in, For the shield radius, To add thrust to the tunnel face, To find the spatial coordinates of the points, Poisson's ratio of soil Shear modulus For the burial depth of the tunnel boring machine's axis, To solve for the spatial distance from the point to the shield tunnel face micro-element; To solve for the spatial distance from the point to the symmetrical point element of the shield tunnel face; Let be the radial distance from the center of the shield tunnel face micro-element. The polar angle is the micro-element of the tunnel face. The standard system in this embodiment... In the diagram, z=0 corresponds to the Earth's surface, y represents the direction of the tunnel boring machine's axis, and the coordinates of the tunnel boring machine cutterhead center are... .
[0033] Considering the cutter head opening ratio The vertical displacement caused by the additional thrust was obtained. ② Calculation model for vertical displacement corresponding to excavated soil volume In this embodiment, the ground deformation caused by excavation at the shield tunnel face is derived using the source-source method. The soil loss caused by excavation is related to the amount of excavated soil. Due to the imbalance of excavation, the soil at the excavation face exhibits a circular radial movement pattern. When the excavation rate at the shield tunnel face is greater than (less than) 100%, the soil at the tunnel face will produce a uniform radial displacement inward (outward).
[0034] The surface data derived using Segaseta based on the sink method ( Simplified formula: This represents the soil loss per unit length due to excavation at the excavation face; other variable names are the same as above.
[0035] ③ Calculation model for vertical displacement corresponding to cutter head friction force The cutterhead of a tunnel boring machine disturbs the surrounding soil through friction. Based on the Mindlin solution, the frictional force of the cutterhead... Cause coordinate system midpoint Vertical displacement for: in, : Cutter head friction; other parameters ( The meaning is the same as the formula for additional thrust at the working face.
[0036] ④ Calculation model for vertical displacement corresponding to the shield tail gap During shield tunneling, a tail gap exists because the shield diameter is larger than the outer diameter of the tunnel segments. As the tunnel boring machine (TBM) excavates forward, the entire shield shell moves forward as well. At this time, the assembled concrete tunnel segments gradually detach from the tail. To fill the tail gap in a timely manner, grouting must be carried out simultaneously. Because the grout is in a fluid state and the grouting pressure is coupled with the deformation of the strata, this process is very complex. As the tail tunnel segments detach, the original tail gap causes initial ground loss, leading to surface subsidence. Meanwhile, the subsequently injected grout, while filling the tail gap, also exerts a certain reverse pressure on the surrounding soil, causing some strata to rebound or heave.
[0037] Given the complexity of this process, this embodiment adopts an equivalent simplification strategy in the calculation: the formation loss after the shield tail disengages is considered to originate from the superposition of two aspects: (1) When the segments just leave the shield tail, consider the soil settlement caused by the gap between the complete shield tail, that is, assume that the soil has completely retracted. (2) Due to the surface uplift caused by the pressure of the grout injected synchronously at the shield tail acting on the surrounding strata, the supporting effect of the grouting is considered.
[0038] The calculation of surface settlement caused by the shield tail gap is based on the sinking method.
[0039] The surface data derived using Segaseta based on the sink method ( The simplified formula can be used to derive the settlement caused by the shield tail gap: The loss per unit length of soil due to the shield tail gap is represented by L, which is the distance between the shield tail and the cutterhead.
[0040] ⑤ Calculation model for vertical displacement corresponding to synchronous grouting pressure at the shield tail Based on the Mindlin solution derivation, due to the synchronous grouting pressure Cause coordinate system midpoint Vertical displacement for: in, To synchronize grouting pressure, For the shield radius, The distance from the shield tail to the cutterhead, and other parameters ( The meaning is the same as the formula for additional thrust at the tunnel face. ⑥ Calculation model for vertical displacement corresponding to shield friction force Based on the Mindlin solution, shield friction force Cause coordinate system midpoint Vertical displacement for: in, For shield friction, the other parameters ( The meaning is the same as the formula for additional thrust at the tunnel face. S130. Based on the vertical displacement caused by each operating parameter, determine the total settlement at the target building location caused by the shield tunneling construction.
[0041] The calculation of ground settlement during shield tunneling requires comprehensive consideration of the additional thrust at the shield face, excavated soil, cutterhead friction, shield tail clearance, synchronous grouting, and shield shell friction. Finally, the total ground settlement value is obtained by superimposing the ground deformation values obtained from each factor, as shown in the following formula: Example 2: This example is a risk assessment method for shield tunneling under buildings, specifically including the following steps: S210. Using the settlement calculation method described in Example 1, determine the total settlement at the target building location caused by shield tunneling.
[0042] S220. Assess the risk of the tunnel boring machine (TBM) passing under the building based on the total settlement at the target building location. For example... Figure 2 As shown, the details are as follows: S221. Obtain key structural indicators of the target building. Due to significant differences in factors such as building structure and construction time, it is necessary to first investigate and analyze the structural information of the building when conducting an impact analysis. The key indicators affecting the building structure mainly include: overall building condition, foundation type, building structure type, and construction time.
[0043] S222. Based on the key structural indicators of the target building, determine the building score corresponding to each key indicator of the target building.
[0044] Based on the results of the building survey, please refer to the table below for scoring. surface Building rating S223. Based on the building scores corresponding to each key indicator, determine the total building score corresponding to the target building, and determine the vulnerability correction coefficient of the target building based on the total building score.
[0045] The scores of the four core indicators are summed and divided into three vulnerability levels (the higher the score, the stronger the vulnerability), providing a grading basis for the correction coefficient: S = S 状况 + S 基础 + S 类型 + S 时间 Based on the rating, vulnerability correction factors for the building are given, namely, the moment of inertia correction factor k. I and elastic modulus correction factor k E Set quantization value: Table 2 Building Vulnerability Correction Factors Vulnerability rating Score range S <![CDATA[Moment of inertia correction factor k I > <![CDATA[Elastic modulus correction factor k E <!-- 9 -->]]> Low (L) S<10 0.90 0.95 (M) 11~20 0.75 0.80 High (H) S>21 0.60 0.65 S224. Based on the vulnerability correction factor and the total settlement at the target building location, calculate the bending strain and angular strain of the target building.
[0046] To calculate the risk of damage to the building, the building is simplified into a deep beam model with a height of H and a length of L. The building height is calculated from the foundation to the eaves, and the roof structure is ignored.
[0047] (1) Delineate the calculation area: Based on the settlement distribution, determine the uplift zone and settlement zone that the building spans, and delineate the corresponding span L. h (Span of the building in the uplifted area) and L S (Span of the building in the settlement zone).
[0048] (2) Calculate the bending strain of the building caused by surface settlement due to shield tunneling. and angular strain in, It refers to the building height. It is the length of the building.
[0049] Corrected moment of inertia : For buildings in the uplifted area For buildings in the settlement zone Modified elastic modulus of building : These are standard values for building materials.
[0050] It is the shear modulus of the building. in, The material's Poisson's ratio.
[0051] S225. Calculate the horizontal strain of the target building based on the difference in horizontal displacement between the two ends of the target building.
[0052] Calculate the difference in horizontal displacement between the two ends of the building to obtain the horizontal strain. in, Given the tunnel axis burial depth, the coordinates of the two ends of the structure are respectively... and ,in S226. Assess the risk of shield tunneling under a building based on the horizontal strain, bending strain, and angular strain of the target building.
[0053] In this embodiment, the horizontal strain is superimposed on the bending strain to obtain the first superimposed strain. The horizontal strain is superimposed on the angular strain to obtain the second superimposed strain. The maximum value between the first and second superimposed strains is taken, and the risk level of the shield tunneling under the building is determined based on this maximum value and a preset risk classification standard. If the maximum value exceeds 0.075%, the building is considered a high-risk building and additional reinforcement measures are required before construction.
[0054] Example 3: In shield tunneling under sensitive structures, traditional parameter adjustments rely on trial and error based on experience, resulting in "lag" and "blindness." This example, based on the "operating parameters-vertical position" relationship model established in Example 1, proposes a real-time inversion adjustment method—using a given settlement threshold as a constraint, when the monitored settlement approaches the alarm value, the operating parameters that need adjustment are directly calculated using analytical formulas, achieving an immediate response of "monitoring data → parameter correction," ensuring that settlement is always controlled within a safe range.
[0055] This embodiment, based on the linear analytical model derived in Embodiment 1, establishes a quantitative mapping of "target settlement → parameter adjustment amount." It prioritizes adjusting source parameters such as the additional thrust at the tunnel face and the excavation soil removal rate, supplemented by synchronous grouting compensation, to achieve precise settlement control. Among these, the core adjustable parameters during shield tunneling are the additional thrust at the tunnel face, excavation soil removal, and synchronous grouting. Tunnel face pressure (controlling the soil balance ahead) and excavation soil removal rate (controlling immediate soil loss) are source parameters that directly determine the initial settlement value; synchronous grouting is a compensatory parameter, mainly compensating for the later shield tail gap. Therefore, the back-calculation priority is: 1. Additional thrust at the tunnel face (most directly affecting the excavation face balance); 2. Excavation soil removal rate (directly controlling soil loss); 3. Synchronous grouting pressure at the shield tail (compensatory adjustment).
[0056] Based on the analytical model derivation in Example 1, the following formulas for calculating shield tunneling operation parameters based on settlement back-calculation can be given: 1. Additional thrust at the working face Within the linear elastic Mindlin solution framework, vertical displacement Additional thrust to the working face It is linear, so we can reverse the formula to calculate the magnitude of the uniform surface load.
[0057] will with With irrelevant constants introduced, the formula for surface subsidence caused by additional thrust at the tunnel face can be rewritten as: in The target displacement to be achieved is (equal to the above formula) Then, calculate the additional thrust at the working face. The analytical expression is 2. Excavation and soil removal The formula for calculating surface settlement based on the sinking method is linear, therefore, the calculation formula for excavated soil can be derived to adjust the excavation soil accordingly for the target displacement: 3. Shield tail synchronous grouting pressure Within the linear elastic Mindlin solution framework, vertical displacement Since the grouting pressure p is linear, we can calculate the magnitude of the grouting pressure in reverse.
[0058] The formula for surface subsidence caused by additional thrust at the tunnel face can be rewritten as: in The target displacement to be achieved is (equal to the above formula) Then the analytical expression for back-calculating the grouting pressure q is: This embodiment describes a dynamic control method for shield tunneling under buildings, specifically including the following steps: S310. Obtain the real-time settlement value of the target building, as well as the relative position of the target building location and the tunnel boring machine.
[0059] S320. When the real-time settlement value exceeds the settlement warning value, the vertical displacement adjustment value is determined based on the difference between the real-time settlement value and the settlement warning value. Then, combined with the vertical displacement calculation model corresponding to the relative position and each operating parameter, the motion parameter adjustment value is calculated in reverse, and the operating parameters of the tunnel boring machine are adjusted.
[0060] S321. Based on the difference between the real-time settlement value and the settlement warning value, the vertical displacement adjustment value is determined. Combined with the vertical displacement calculation model corresponding to the relative position and the additional thrust at the tunnel face, the adjustment value of the additional thrust at the tunnel face is calculated, and then the additional thrust at the tunnel face of the shield machine is adjusted. For example... Figure 3 As shown, it specifically includes: S322. Obtain the real-time settlement value of the target building again. If the real-time settlement value still exceeds the settlement warning value, determine the vertical displacement adjustment value based on the difference between the real-time settlement value and the settlement warning value. S323. Based on the vertical displacement adjustment value determined in step S322, and combined with the vertical displacement calculation model corresponding to the relative position and the amount of excavated soil, the adjustment value of the amount of excavated soil is calculated in reverse, and then the amount of excavated soil of the tunnel boring machine is adjusted. S324. Obtain the real-time settlement value of the target building again. If the real-time settlement value still exceeds the settlement warning value, determine the vertical displacement adjustment value based on the difference between the real-time settlement value and the settlement warning value. S325. Based on the vertical displacement adjustment value determined in step S324, and combined with the vertical displacement calculation model corresponding to the relative position and the synchronous grouting pressure at the shield tail, the excavation soil volume adjustment value is calculated in reverse, and then the synchronous grouting pressure at the shield tail of the tunnel boring machine is adjusted.
[0061] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0062] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-including system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.
[0063] More specific examples (a non-exhaustive list) of computer-readable media include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the aforementioned program can be printed, because the aforementioned program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.
[0064] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.
[0065] In the foregoing description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0066] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
[0067] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.
Claims
1. A method for calculating settlement when a shield tunnel passes under a building, characterized in that, include: The relative position of the target building location and the tunnel boring machine (TBM) is obtained, as well as the operating parameters of the TBM, including the additional thrust at the tunnel face, the amount of excavated soil, the friction of the cutterhead, the tail clearance, the synchronous grouting pressure at the tail, and the friction of the shield shell. Based on the relative position of the target building location and the tunnel boring machine, as well as the tunnel boring machine's operating parameters and the vertical displacement calculation model corresponding to each operating parameter, the vertical displacement at the target building location caused by each operating parameter is determined. Based on the vertical displacement caused by various operating parameters, the total settlement at the target building location caused by shield tunneling is determined.
2. The method for calculating settlement of a shield tunneling structure according to claim 1, characterized in that, The calculation model for the vertical displacement corresponding to the additional thrust at the working face, the frictional force of the cutterhead, the synchronous grouting pressure at the shield tail, and the frictional force of the shield shell is derived and solved using the Mindlin method.
3. The method for calculating settlement of a shield tunneling structure according to claim 1, characterized in that, The calculation model for the vertical displacement corresponding to the excavated soil volume and the shield tail gap is derived using the Segaseta sink method.
4. A method for risk assessment of shield tunneling under buildings, characterized in that, include: The total settlement at the target building location caused by shield tunneling is determined by using the settlement calculation method described in any one of claims 1 to 3. The risk of the tunnel boring machine passing under the building is assessed based on the total settlement at the target building location.
5. The method for risk assessment of shield tunneling under buildings according to claim 4, characterized in that, The assessment of the risk of the tunnel boring machine (TBM) passing under the building, based on the total settlement at the target building location, includes: Obtain key structural indicators of the target building, including the overall condition of the building, the type of foundation, the type of building structure, and the construction time. Based on the key structural indicators of the target building, determine the building score corresponding to each key indicator of the target building; Based on the building scores corresponding to each key indicator, the total building score corresponding to the target building is determined, and the vulnerability correction coefficient of the target building is determined based on the total building score. Based on the vulnerability correction factor and the total settlement at the target building location, the bending strain and angular strain of the target building are calculated. Calculate the horizontal strain of the target building based on the difference in horizontal displacement between its two ends; The risk of the shield tunnel passing under the building is assessed based on the horizontal strain, bending strain, and angular strain of the target building.
6. The method for risk assessment of shield tunneling under buildings according to claim 5, characterized in that, The determination of the vulnerability correction factor for the target building based on the overall building score includes: Based on the total building score corresponding to the target building, the vulnerability correction factor of the target building is determined by referring to the building vulnerability correction factor table.
7. The method for risk assessment of shield tunneling under buildings according to claim 5 or 6, characterized in that, The vulnerability correction factor includes the moment of inertia correction factor and the elastic modulus correction factor.
8. The method for risk assessment of shield tunneling under buildings according to claim 5, characterized in that, The assessment of the risks of shield tunneling under a building, based on the horizontal strain, bending strain, and angular strain of the target building, includes: The first superimposed strain is obtained by superimposing the horizontal strain onto the bending strain; the second superimposed strain is obtained by superimposing the horizontal strain onto the angular strain. The maximum value between the first superimposed strain and the second superimposed strain is taken, and the risk level of the shield tunneling under the building is determined based on the maximum value and the preset risk classification standard.
9. A method for dynamic control of shield tunneling under buildings, characterized in that, include: S310. Obtain the real-time settlement value of the target building, as well as the relative position of the target building location and the tunnel boring machine; S320. When the real-time settlement value exceeds the settlement warning value, the vertical displacement adjustment value is determined based on the difference between the real-time settlement value and the settlement warning value. Then, combined with the vertical displacement calculation model corresponding to the relative position and each operating parameter, the motion parameter adjustment value is calculated in reverse, and the operating parameters of the tunnel boring machine are adjusted.
10. The method for dynamic control of shield tunneling under buildings according to claim 9, characterized in that, Step S320 includes: S321. Based on the vertical displacement adjustment value, combined with the vertical displacement calculation model corresponding to the relative position and the additional thrust at the tunnel face, the adjustment value of the additional thrust at the tunnel face is calculated in reverse, and then the additional thrust at the tunnel face of the shield machine is adjusted. S322. Obtain the real-time settlement value of the target building again. If the real-time settlement value still exceeds the settlement warning value, determine the vertical displacement adjustment value based on the difference between the real-time settlement value and the settlement warning value. S323. Based on the vertical displacement adjustment value determined in step S322, and combined with the vertical displacement calculation model corresponding to the relative position and the amount of excavated soil, the adjustment value of the amount of excavated soil is calculated in reverse, and then the amount of excavated soil of the tunnel boring machine is adjusted. S324. Obtain the real-time settlement value of the target building again. If the real-time settlement value still exceeds the settlement warning value, determine the vertical displacement adjustment value based on the difference between the real-time settlement value and the settlement warning value. S325. Based on the vertical displacement adjustment value determined in step S324, and combined with the vertical displacement calculation model corresponding to the relative position and the synchronous grouting pressure at the shield tail, the excavation soil volume adjustment value is calculated in reverse, and then the synchronous grouting pressure at the shield tail of the tunnel boring machine is adjusted.