Evaluation method of ground settlement deformation in shield tunnel construction stage considering recovery time

Abstract

The present application relates to a kind of considering recovery time's shield tunnel construction stage surface subsidence deformation evaluation method, this method includes: by real-time acquisition shield tunnel construction area surface subsidence absolute deformation and deformation rate, to determine the time when ground performance is disturbed and recovery stable time and calculate recovery time;Based on monitoring data, the way of combining single index and double index is used to calculate the ground performance index, combined with average recovery time to build toughness evaluation model, divide surface subsidence deformation toughness grade, finally output evaluation result and formulate corresponding construction control measures.The present application includes recovery time in evaluation system, solves the defect that present method ignores stratum recovery characteristics, improves the accuracy of surface subsidence deformation evaluation, can identify construction risk in time, provides reliable basis for shield tunnel construction safety early warning, protects surrounding infrastructure safety, reduces potential loss caused by stratum deformation.

Description

Technical Field

[0001] This invention relates to the field of surface deformation evaluation technology, and specifically to a method for evaluating surface settlement and deformation during the construction phase of a shield tunnel that takes recovery time into account. Background Technology

[0002] With the acceleration of urbanization, large-diameter shield tunnels are increasingly used in densely populated urban areas. Their construction inevitably disturbs the surrounding strata, causing surface settlement and deformation, which in turn threatens the safety of above-ground buildings, roads, pipelines, and other infrastructure. Therefore, effectively controlling surface settlement and deformation and establishing scientific and reasonable evaluation methods for surface settlement and deformation are crucial to ensuring the safety of shield tunnel construction.

[0003] Currently, existing methods for evaluating surface settlement and deformation in shield tunnels mostly focus on monitoring a single indicator, such as deformation amount or deformation rate, neglecting the impact of the strata's recovery characteristics after disturbance on the deformation evaluation results. This leads to biased evaluation results and makes it difficult to fully reflect the surface strata's resistance to disturbance and stable recovery characteristics.

[0004] While existing toughness assessment models have been applied in tunnel engineering, they are mostly applicable to the operational phase and do not fully consider the characteristics of ground disturbance during shield tunneling. Furthermore, they do not incorporate recovery time as a core influencing factor into the evaluation system, making it impossible to accurately quantify the dynamic evolution of surface settlement and deformation and the safety status during shield tunnel construction. In addition, existing evaluation methods lack unified grading standards, resulting in insufficient practicality and guidance of the evaluation results, making it difficult to meet the needs of safety early warning and construction control at engineering sites. Summary of the Invention

[0005] The present invention proposes a method for evaluating surface settlement and deformation during the construction stage of shield tunnels that takes into account recovery time, which can at least solve one of the technical problems in the background art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for evaluating surface settlement and deformation during the construction phase of a shield tunnel, taking recovery time into account, involves the following steps performed using computer equipment. S1. Real-time acquisition of settlement and deformation data of surface monitoring points in the shield tunnel construction area, the data including absolute surface deformation and deformation rate; based on the acquired settlement and deformation data, determining the time when the surface performance of each surface monitoring point is disturbed and the time when it recovers to stability, and calculating the recovery time of each monitoring point from the difference between the time of recovery to stability and the time of disturbance. S2. Based on the absolute deformation and deformation rate obtained from S1, the surface performance indicators of each surface monitoring point are calculated separately or jointly. S3. Collect the recovery time of each monitoring point calculated in S1, and calculate the average recovery time of all monitoring points; S4. Input the surface performance index obtained in S2 and the average recovery time obtained in S3 into the pre-constructed resilience evaluation model to calculate the resilience evaluation index of each monitoring point. S5. Based on the values ​​of the toughness evaluation index calculated in S4, determine the surface settlement deformation toughness level of each surface monitoring point according to the preset grading standard, and output the evaluation results.

[0007] In another aspect, the present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the method described above.

[0008] In another aspect, the present invention also discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method described above.

[0009] As can be seen from the above technical solution, the surface settlement deformation evaluation method for shield tunnel construction stage considering recovery time of the present invention makes up for the deficiency of existing evaluation models that do not fully consider the stratum recovery characteristics. By introducing the recovery time parameter and combining the two core indicators of absolute surface settlement deformation and deformation rate, a scientific evaluation model and grading standard are constructed to achieve accurate evaluation of surface settlement deformation during shield tunnel construction stage and provide a reliable basis for construction safety early warning.

[0010] This invention outputs the surface settlement and deformation evaluation results of each monitoring point based on the calculated toughness evaluation index Re and the grading evaluation standard, and formulates corresponding construction control measures for different toughness levels. Among them, the results of the dual-index evaluation method are more secure and are given priority for evaluation of high-risk construction areas (such as under buildings and roads), while the single-index evaluation method can be used as an alternative when data is missing.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The introduction of the recovery time parameter compensates for the deficiency of existing evaluation methods in ignoring formation recovery characteristics. Traditional evaluations of surface settlement and deformation during shield tunnel construction often focus on monitoring single or dual indicators such as absolute deformation and deformation rate, failing to consider the recovery characteristics of the strata after disturbance. This invention, for the first time, incorporates recovery time into the surface settlement and deformation evaluation system. By defining the time when surface performance is disturbed and the time when it returns to stability, the recovery time is quantitatively calculated, thus more comprehensively reflecting the strata's resistance to disturbance and self-recovery characteristics. This addresses the technical blind spot of existing methods that "only assess losses, not recovery."

[0012] 2. A resilience evaluation model integrating recovery time and performance indicators was constructed to improve the scientific rigor and accuracy of the evaluation results. This invention combines mean recovery time with surface performance indicators to construct a toughness evaluation index calculation model in the form of an exponential function. This model comprehensively reflects the degree of performance degradation and recovery speed of the surface under construction disturbance, achieving a quantitative description of the dynamic evolution process of surface subsidence and deformation. Compared with existing single-threshold or static evaluation methods, the toughness evaluation results of this invention more accurately reflect the actual safety status of the strata, significantly improving the accuracy and engineering applicability of the evaluation.

[0013] 3. An evaluation strategy combining single and dual indicators is adopted to balance data completeness and evaluation security. This invention provides three methods for calculating surface performance indicators based on absolute deformation, deformation rate, and their product. It explicitly prioritizes the dual-indicator evaluation method for high-risk construction areas, while using the single-indicator evaluation method as an alternative when data is missing. This design ensures the safety and conservatism of the evaluation results under conditions of sufficient data, while also improving the method's adaptability and robustness in situations where on-site data collection is incomplete.

[0014] 4. A unified standard for resilience grading was established, enhancing the operability and guidance of the evaluation results. This invention classifies surface subsidence deformation toughness into four levels: high toughness, medium toughness, low toughness, and no toughness, and formulates corresponding construction control measures for each level. This classification standard is clear, easy to implement on-site, and can intuitively reflect the severity and urgency of surface subsidence deformation. It provides construction managers with clear safety warning signals and control guidelines, effectively reducing safety risks caused by ground deformation.

[0015] 5. To achieve dynamic evaluation and timely early warning of surface settlement throughout the entire shield tunnel construction process. Based on real-time monitoring data, this invention can identify disturbances in the early stages of surface performance degradation and dynamically track recovery time and toughness index changes throughout the construction process, demonstrating excellent timeliness. By periodically or continuously outputting the toughness level evaluation results of each monitoring point, high-risk areas can be identified in a timely manner, and targeted control measures can be taken. This avoids the drawbacks of traditional methods that rely on "post-event evaluation and delayed response," providing a reliable technical guarantee for the safety of shield tunnel construction.

[0016] 6. Ensure the safety of surrounding infrastructure and reduce potential economic losses caused by ground deformation. This invention scientifically evaluates the toughness level of surface settlement deformation and guides the optimization of construction parameters (such as adjusting the synchronous grouting volume, controlling the tunneling speed, and reinforcing the strata). It can effectively control surface deformation within the allowable range, reduce secondary disasters such as cracking of buildings above, road collapse, and pipeline damage caused by uneven settlement, thereby ensuring the safe operation of surrounding infrastructure and significantly reducing engineering accidents and economic losses caused by strata deformation. Attached Figure Description

[0017] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram of tunnel surface settlement monitoring according to an embodiment of the present invention; Figure 3 The toughness index Re is calculated under different evaluation methods in the embodiments of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, but not all embodiments.

[0019] like Figure 1 As shown in this embodiment, the method for evaluating surface settlement and deformation during the construction stage of a shield tunnel, which takes recovery time into account, includes the following steps: Step 1, real-time acquisition of monitoring data; Step 2, calculation of surface performance indicators; Step 3, calculation of average recovery time; Step 4, calculation of toughness evaluation indicators; Step 5, classification of surface deformation levels; and Step 6, application of deformation evaluation results.

[0020] Specifically, it includes the following steps: like Figure 2 As shown, monitoring points were set up on the surface of the shield tunnel construction area to collect the absolute deformation amount ΔM(t) and deformation rate ΔK(t) of the surface settlement in real time throughout the entire construction process. The monitoring time series was recorded to determine the time t when the surface was disturbed. i and the time t for restoring stability Calculate the recovery time Δt=t -t i ; where t i The point at which the surface performance index Q(t) drops below 95% of the initial performance Q0 and continues to decline is defined as t. The time is defined as the moment when the surface performance index Q(t) returns to a stable level and shows no significant decline for three consecutive monitoring days.

[0021] A combination of single-indicator and dual-indicator methods is used to calculate the land surface performance index Q(t) based on the collected monitoring data, specifically including: Single-index evaluation method 1 (based on absolute ground deformation): , where ΔMmax is the maximum allowable ground deformation during shield tunnel construction. According to GB 50446-2017 "Code for Construction and Acceptance of Shield Tunnelling Method", ΔMmax is set to 30 mm for ground subsidence, and ΔMmax is set to 10 mm for ground heave; Single-index evaluation method 2 (based on ground deformation rate): , where ΔKmax is the maximum allowable ground deformation rate during shield tunnel construction. According to GB 50446-2017 "Code for Construction and Acceptance of Shield Tunnelling Method", Kmax is set to 3 mm / d; Dual-index evaluation method: Q3(t)=Q1(t)×Q2(t), which comprehensively considers the synergistic effect of absolute deformation and deformation rate.

[0022] Select the recovery time Δt of all monitoring points in the shield tunnel construction area j , and calculate the average recovery time , where N is the number of monitoring points, and Δtj is the recovery time of the j-th monitoring point.

[0023] Introduce the influence of recovery time on the resilience of ground subsidence deformation, and construct a calculation model for the resilience evaluation index Re of ground subsidence deformation: , where a>1, b>0, and QD(t) is the ground performance index after disturbance (select Q1(t), Q2(t) or Q3(t)); preferably, a is set to the natural base e, and b is set to 1.63, so as to ensure the distribution rationality and engineering applicability of the resilience evaluation index.

[0024] Based on the calculation result of the resilience evaluation index Re, combined with engineering safety requirements, the ground subsidence deformation resilience is divided into 4 grades, and the specific grading criteria are as follows: High resilience: Re>0.75, the ground deformation is small, the safety performance does not decrease significantly after being disturbed by construction, and the recovery capacity and adaptability are good; Medium resilience: 0.50<Re≤0.75, the ground deformation is small, the safety performance does not decrease significantly after being disturbed by construction, and the overall deformation is within a controllable range; Low resilience: 0.25<Re≤0.50, the ground deformation is significant, the safety performance decreases obviously after being disturbed by construction, and construction control or deformation recovery measures need to be taken; No resilience: Re≤0.25, the ground deformation is extremely large, which is prone to major accidents such as ground collapse and endangers the safety of ground buildings.

[0025] The following is an example for illustration: Step 1: Deploy monitoring points on the ground surface. Monitoring points are deployed on the ground surface from the 1st to the 37th ring of the tunnel boring machine (TBM). One monitoring point is deployed every 10m longitudinally along the tunnel axis, and one monitoring section is deployed every 50m laterally, with 7 monitoring points deployed in each section. Deep-buried deployment is used. The absolute deformation of surface settlement ΔM(t) and the deformation rate ΔK(t) are collected in real time during TBM tunneling. The monitoring time series is recorded, and the disturbance time t at each monitoring point is determined. i and recovery time t Calculate the recovery time Δt; where t i t is the moment when Q(t) drops below 95% of Q0 and continues to decrease. This is the point at which Q(t) stabilizes and shows no significant decrease for three consecutive days.

[0026] Step 2: Calculate surface performance indicators; according to GB 50446-2017 "Code for Construction and Acceptance of Shield Tunneling Method", the maximum allowable surface settlement deformation ΔM max =30mm, maximum allowable deformation rate ΔK max =3mm / d.

[0027] The surface performance index Q(t) was calculated using three different evaluation methods: Single-index evaluation method 1 (based on the absolute deformation of the surface): Single-index evaluation method 2 (based on surface deformation rate): The dual-index evaluation method is: Q3(t) = Q1(t) × Q2(t).

[0028] Step 3: Calculate the average recovery time; calculate the recovery time Δt of the selected monitoring points under the three evaluation conditions. j and mean recovery time Δ The average recovery time of the surface is 12.88 days under the evaluation method based on the absolute deformation of the surface; 14.01 days under the evaluation method based on the deformation rate of the surface; and 14.34 days under the dual-index evaluation method.

[0029] Step 4: Calculate the surface toughness evaluation index; toughness evaluation index Where a>1, b>0, and QD(t) is the surface performance index after disturbance (selecting Q1(t), Q2(t), or Q3(t)); a takes the natural base e, and b takes 1.63 to ensure the reasonable distribution of toughness evaluation indexes and their engineering applicability.

[0030] Step 5: Classify the toughness level according to the toughness evaluation index Re; the calculation results are as follows. Figure 3As shown, the calculation results indicate that when using Q1(t) and Q2(t) as single indicators for evaluation, the calculated Re values ​​are quite similar, with most monitoring points having Re values ​​between 0.50 and 0.83, indicating high and medium toughness. When using Q3(t) as a dual indicator for evaluation, the Re values ​​are between 0.25 and 0.60, with 75% being medium toughness and 25% being low toughness. The calculated Re values ​​using the single indicator evaluation are significantly higher than those using the dual indicator evaluation method, indicating that the evaluation results of the dual indicator method are more conservative and better meet the engineering safety requirements.

[0031] Step 6: Apply the surface settlement and deformation evaluation results and take targeted measures; for low toughness monitoring points (mainly concentrated in the shallow overburden soft soil section from ring 12 to ring 27), adjust the synchronous grouting volume, strengthen the stratum reinforcement measures, reduce the shield tunneling speed, and ensure that the surface settlement and deformation are within a controllable range; for high toughness and medium toughness monitoring points, maintain normal construction parameters and continue monitoring.

[0032] In another aspect, the present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the method described above.

[0033] In another aspect, the present invention also discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method described above.

[0034] In another embodiment provided in this application, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to execute any of the above embodiments of the method for evaluating surface settlement and deformation during the shield tunnel construction stage that takes recovery time into account.

[0035] It is understood that the systems, devices, and storage media provided in the embodiments of the present invention correspond to the methods provided in the embodiments of the present invention, and the explanations, examples, and beneficial effects of the relevant content can be referred to the corresponding parts of the above methods.

[0036] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. 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 limitations, 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.

[0038] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0039] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating surface settlement and deformation during the construction phase of a shield tunnel, considering recovery time, characterized in that, comprising the following steps, S1. Acquire settlement and deformation data of surface monitoring points in the shield tunnel construction area in real time, wherein the data includes the absolute surface deformation amount and the deformation rate; based on the acquired settlement and deformation data, determine the disturbance moment and the recovery stabilization moment of the surface performance of each surface monitoring point, and calculate the recovery time of each monitoring point from the difference between the recovery stabilization moment and the disturbance moment; S2. Based on the absolute deformation amount and the deformation rate acquired in S1, the surface performance index of each surface monitoring point is calculated separately or in combination; S3. Collect the recovery time of each monitoring point calculated in S1, and calculate the average recovery time of all monitoring points; S4. Input the surface performance index obtained in S2 and the average recovery time obtained in S3 into a pre-built resilience evaluation model, and calculate the resilience evaluation index of each monitoring point; S5. According to the value of the resilience evaluation index calculated in S4, determine the surface settlement deformation resilience grade of each surface monitoring point according to a preset grade classification standard, and output the evaluation result.

2. The method for evaluating surface settlement and deformation during shield tunnel construction considering recovery time, as described in claim 1, is characterized in that: specifically comprising, S1. Set up monitoring points on the ground surface in the shield tunnel construction area to collect the absolute deformation Δ of ground settlement in real time throughout the entire construction process. M ( t and deformation rate Δ K ( t Record the monitoring time series to determine the moment when the surface is disturbed. t i and the moment of recovery to stability t Calculate the recovery time Δ t = t - t i ; S2. Using a combination of single and dual indicators, surface performance indicators are calculated based on the collected monitoring data. Q(t) ; S3, Select the recovery time Δ of all monitoring points within the construction area. t j Calculate the average recovery time, and the formula for calculating the average recovery time is as follows: ,in, N Δ is the number of monitoring points. t j For the first j Recovery time for each monitoring point; S4, combined with mean recovery time Δ and surface performance indicators Q ( t To construct a toughness evaluation index for surface subsidence deformation. Re The calculation model was used to calculate the results for each monitoring point. Re value; S5, according to Re The system classifies surface settlement deformation toughness into four levels: high, medium, low, and no toughness. It then outputs the evaluation results of each monitoring point and formulates corresponding construction control measures for different toughness levels.

3. The method for evaluating surface settlement and deformation during shield tunnel construction considering recovery time, as described in claim 2, is characterized in that: In S1, t i The point at which the surface performance index Q(t) drops below 95% of the initial performance Q0 and continues to decline is defined as t. The time is defined as the moment when the surface performance index Q(t) returns to a stable level and shows no significant decline for three consecutive monitoring days.

4. The surface settlement deformation evaluation method for the shield tunnel construction stage considering recovery time according to claim 2, characterized in that: The single index includes the absolute deformation of the land surface. and deformation rate ; The dual indexes are Q3(t)=Q1(t)×Q2(t), where ΔMmax is the maximum allowable surface deformation amount during the shield tunnel construction process, ΔM(t) is the surface settlement deformation amount at time t, ΔKmax is the maximum allowable surface deformation rate during the shield tunnel construction process, and ΔK(t) is the surface settlement deformation rate at time t.

5. The method for evaluating surface settlement and deformation during shield tunnel construction considering recovery time, as described in claim 4, is characterized in that: ΔM max According to GB 50446-2017 "Code for Construction and Acceptance of Shield Tunneling Method", ΔK is taken as 30mm when surface settlement occurs and 10mm when uplift occurs; max According to GB 50446-2017, the value is determined to be 3 mm / d.

6. The method for evaluating surface settlement and deformation during shield tunnel construction considering recovery time, as described in claim 4, is characterized in that: The toughness evaluation model for surface subsidence deformation , where a>1, b>0, and QD(t) are Q1(t), Q2(t), and Q3(t).

7. The method for evaluating surface settlement and deformation during shield tunnel construction considering recovery time, as described in claim 6, is characterized in that: In the resilience evaluation model for surface settlement deformation, a is the natural base e, and b is 1.63; the degree of surface performance loss is quantified by combining the monitored time series and the QD(t) variation curve.

8. The method for evaluating surface settlement and deformation during shield tunnel construction considering recovery time, as described in claim 2, is characterized in that: In S5, the classification criteria for the surface settlement deformation resilience grade are: high resilience with Re>0.75, medium resilience with 0.50<Re≤0.75, low resilience with 0.25<Re≤0.50, and no resilience with Re≤0.

25.

9. The method for evaluating surface settlement and deformation during shield tunnel construction considering recovery time, as described in claim 2, is characterized in that: In S2, the dual-index evaluation method is used for high-risk construction areas, and the single-index evaluation method is used as an alternative when data is missing.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, the processor is caused to execute the steps of the method according to any one of claims 1 to 9.

Images