A long tunnel multi-working face construction period deduction method and system based on spatial optimization

Abstract

The present application relates to the technical field of water conservancy construction progress plan and control, in particular to a long tunnel multi-working face construction period deduction method and system based on space optimization. The geological sectional data is sorted according to the stake number and the adjacent sectional end stake numbers are checked to see if they are equal, the data gaps or overlaps are detected and blocked, and the standardized geological feature set is obtained; according to the corresponding relationship between the surrounding rock category and the footage speed, the interval time consumption is defined in the sectional overlapping accumulation mode; for two working faces of adjacent and opposite tunneling, the bisection method is used to find the zero point of the time difference value containing the buffer offset of the leading working face, and the dynamic through stake number is determined; the maximum value of the excavation completion time of the two working faces triggers the secondary lining, and the interval time consumption is accumulated in the reverse direction along the direction of the construction channel intersection stake number from the dynamic through stake number, and the lining completion node is obtained; the latest one in each completion node is taken as the key line control node and output.

Description

Technical Field

[0001] This invention relates to the field of water conservancy project construction schedule planning and control technology, specifically to a method and system for extrapolating the construction period of long tunnels with multiple working faces based on spatial optimization. Background Technology

[0002] In the construction of long-distance tunnel projects in fields such as water conservancy and hydropower, railways, and highways, multiple construction channels (such as inclined shafts, vertical shafts, and horizontal tunnels) are usually arranged along the tunnel axis to meet the construction period requirements, thus forming multiple working faces for bidirectional excavation of the main tunnel. The progress control of this type of project has strong spatiotemporal coupling characteristics: First, the geological conditions traversed by the tunnel axis are not uniformly distributed, and the surrounding rock categories (such as Class I to Class V) are different in different sections, resulting in large differences in the excavation and lining construction progress rates of each section; Second, due to the different geological conditions and different entry times faced by two adjacent working faces excavating in opposite directions, their breakthrough position (meeting station) changes dynamically with the excavation progress on both sides, making it difficult to determine in advance; Third, the secondary lining of the tunnel usually can only be carried out after the excavation of the corresponding section is completed, and its operation direction is often opposite to the excavation direction, that is, a backward lining is adopted, which makes the lining process subject to strong constraints in terms of spatial location and process sequence of excavation completion.

[0003] Currently, the industry mainly relies on two methods to prepare project schedules for this type of project. One method involves engineers manually calculating the schedule segmented by using spreadsheets: based on the advance rate corresponding to the surrounding rock type of each section, the excavation time is estimated segment by segment, and the meeting point between working faces is calculated. To simplify the calculation, this manual method usually calculates the meeting point by dividing the average speed or the total excavation time equally. It is difficult to fully account for the impact of sudden changes in the surrounding rock along the excavation path on the advance rate. There is a discrepancy between the calculated meeting point and the actual breakthrough point. The resulting project schedule often deviates from the actual project, and the calculation process is complicated and prone to errors in temporal and spatial logic. Another type uses general project management software (such as schedule management software based on the critical path method and Gantt chart connection): The underlying logic of this type of software is oriented towards the temporal relationship of "task - predecessor task - duration", lacks the concept of spatial coordinates along the tunnel mileage, and has difficulty in handling strong constraint relationships such as "using the spatial connection position as the trigger condition for subsequent processes, and the process time needs to be reversed in the opposite direction of space", so it cannot automatically schedule reverse processes such as reverse secondary lining.

[0004] Furthermore, most existing progress estimation methods directly use the entered segmented geological data for calculation. However, in engineering practice, the start and end station numbers of segmented geological data may have gaps, overlaps, or boundaries between segments during input. Such data defects are often only detected when the calculation results are abnormal, affecting the reliability of the estimation results. Additionally, when two opposing working faces are nearing breakthrough, according to construction safety requirements, one side must stop, and the other side must advance unidirectionally to complete the final segment. Existing simplified estimation methods usually treat breakthrough as a natural encounter between the two working faces, failing to incorporate the aforementioned unidirectional breakthrough safety requirements into the calculation of the encounter position.

[0005] Some existing methods focus on displaying the tunnel construction progress graphically, but they emphasize the visualization of progress and do not provide specific methods for accurately solving the dynamic breakthrough point under non-uniform geological conditions, or for extrapolating the construction period of the retrograde secondary lining based on this.

[0006] In summary, existing technologies are insufficient to accurately calculate the dynamic connection position of multiple working faces under complex geological conditions, and to automatically schedule the secondary lining construction period in accordance with the reverse construction process. This often leads to the project schedule deviating from the actual project, resulting in idle resources or project delays. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the above-mentioned technologies by providing a method and system for projecting the construction period of multiple working faces in long tunnels based on spatial optimization. Under complex geological conditions, this method can accurately calculate the dynamic connection position of multiple working faces and automatically complete the secondary lining schedule that conforms to the reverse construction process.

[0008] To achieve the above objectives, the present invention provides a method for project duration estimation of long tunnels with multiple working faces based on spatial optimization, characterized by comprising: Obtain the global start and end station numbers of the tunnel, the intersection station numbers of each construction passage and the available entry time, as well as geological segment data including the start and end station numbers of each segment and the surrounding rock type; The geological segment data is sorted by station number, and the end station number of the previous segment and the start station number of the next segment are checked to see if they are equal. If there are unequal adjacent segment pairs, the simulation is interrupted and an alarm is issued, and subsequent steps are not executed. If they are all equal, the sorted geological segment data is determined as a standardized geological feature set. Based on the preset correspondence between the surrounding rock type and the excavation and lining speeds, the surrounding rock type of each segment in the standardized geological feature set is replaced with the corresponding speed to obtain the speed segment set; the interval time of any station interval is defined as: the sum of the overlap length between the interval and each speed segment divided by the corresponding speed. Select the first and second working faces that are adjacent and excavating in opposite directions, and obtain their starting station number st respectively. L Start time t L and starting station number st R Start time t R ; Receive specified information to determine a dominant working face from the two, and set a buffer time offset for the dominant working face; With st L for lower bound, st R Establish a search interval for the upper limit of the chainage, take the midpoint as the trial breakthrough chainage m, and calculate the time difference value ΔT(m) according to the following formula: ΔT(m)=[t L +f(st L ,m)]–[t R +f(st R [,m)]–Offset In the formula f(st) L ,m),f(st R m) are the values ​​obtained according to the interval time definition, respectively. L To m, from st R The interval time up to m; Offset is the buffer time required for the dominant working face when one of the two opposing working faces stops and the dominant working face breaks through in one direction; When ΔT(m)>0, update the upper bound of the search interval to m; when ΔT(m)<0, update the lower bound of the search interval to m. Take the midpoint of the updated interval as the new m and recalculate ΔT(m). Repeat the above update and calculation until the length of the search interval is less than 0.001 meters. Then, determine the m at this time as the dynamic connection station number between the first working face and the second working face. For opposing interconnected sections defined by the dynamic interconnected station number, the maximum value between the excavation completion time of the first and second working faces is taken as the trigger start time for the secondary lining process of the opposing interconnected section. Taking the dynamic connection chainage of the opposite through section as the lining start point and the construction channel intersection chainage corresponding to the first or second working face as the lining end point, starting from the start time, the interval time is called in reverse along the direction from the lining start point to the lining end point, and the duration and completion node of the secondary lining process are obtained. Based on the excavation completion nodes of each working face and the secondary lining completion nodes of each opposite through section, the node with the latest completion time is determined as the critical path control node and its completion time is output.

[0009] In this design, by verifying the continuity of geological segment data, gaps or overlaps in segment data can be automatically detected and blocked before simulation, ensuring the reliability of the input foundation. The conversion from surrounding rock type to advance speed is used to accurately map spatial geological information into a time calculation basis. In particular, by repeatedly performing binary search on the time difference value containing buffer offsets, and determining the search direction by its positive or negative sign, it can quickly converge to a preset accuracy (e.g., 0.001 meters), solving for the dynamic connection point where the difference in arrival time between two working faces equals the set buffer time offset. Traditional manual segment calculations typically calculate the meeting position by dividing the average speed or total time equally, and lack a deterministic optimization process based on spatial binary search of station numbers. This method obtains a definite and reproducible connection station number. Simultaneously, the buffer time offset of the dominant working face is introduced, making the simulation results conform to the unidirectional connection process arrangement in actual construction. The maximum value of the excavation completion time triggers the secondary lining process, and the lining duration is accumulated in reverse, achieving seamless connection between excavation and lining, and ultimately automatically identifying the critical path control node.

[0010] Preferably, when Offset is positive, the dynamic breakthrough station number is offset from the breakthrough station number when Offset is zero in a direction away from the dominant working face.

[0011] In this design, it is clearly defined that when the Offset is positive, the dynamic breakthrough station number deviates from the dominant working face, that is, the dominant working face undertakes a longer tunneling section. This realistically simulates the construction practice of "stopping on one side and tunneling through from the dominant face in one direction", ensuring that the breakthrough station number can provide a definite solution that conforms to the process logic under different dominant face selections.

[0012] Preferably, the time consumption of each station interval is accumulated in reverse order, including: along the direction from the dynamic through station to the lining end point, the station range from the lining start point to the lining end point is divided into multiple continuous sub-intervals according to the segment boundary of the segment set of the advance speed; for each sub-interval, the length of the sub-interval is divided by the lining advance speed corresponding to the sub-interval to obtain the lining time of the sub-interval; and the lining time of each sub-interval is accumulated sequentially.

[0013] In this design, the lining construction process is decomposed into multiple continuous sub-intervals defined by the segment boundaries of the advance speed. For each sub-interval, the lining advance speed corresponding to that interval is accumulated over time, ensuring that the lining simulation can fully reflect the impact of surrounding rock changes on the lining speed within the same opposing penetration section. The reverse accumulation (pushing back from the penetration point towards the construction channel) fully conforms to the spatiotemporal logic of secondary lining construction from the penetration position outwards, guaranteeing the authenticity and reliability of the lining completion node calculation.

[0014] Preferably, the lining starting point is replaced with one of the following: the physical midpoint station of the opposing through section, the dynamic through station, or an externally input custom station.

[0015] In this design, the starting point of the lining is expanded to three optional modes: the physical midpoint of the opposite through section, the dynamic through station, or the externally customized station. This can adapt to the lining division habits under different construction processes and greatly improve the versatility and adaptability of this method in different tunnel construction organization design schemes.

[0016] Preferably, the interval time is calculated as follows: for any input station interval [a,b], extract all the advance speed segments that overlap with the station interval [a,b] from the advance speed segment set, divide the intersection length of each overlapping segment with [a,b] by the advance speed corresponding to the overlapping segment to obtain the segment time, and then sum up all the segment times and output them.

[0017] In this design, the time consumption of any station interval is given by segmented overlapping and accumulation. It automatically handles the complex situation of spanning multiple segments with different advance speeds, without the need for manual division of calculation segments. This ensures that the time calculation result of any station interval is an accurate calculation result based on the given advance speed, providing a high-precision basic operator for subsequent breakthrough point search and lining simulation.

[0018] Preferably, it also includes: outputting a one-dimensional process data table, which lists the starting station number, start time, and completion time of the excavation process of each working face in rows, as well as the starting and ending station numbers, trigger start time, and completion time of the secondary lining process of each opposite through section.

[0019] In this design, the simulation results are presented in the form of a structured data table. Each row lists the start and end chainages and time nodes of the excavation process of each working face and the secondary lining process of the opposite connecting section, making the spatiotemporal layout of the entire construction period clear at a glance. This facilitates direct import into project management software or data processing, providing standardized and reusable digital results for construction planning and schedule management.

[0020] Preferably, it further includes: generating a construction progress time-distance diagram in a two-dimensional rectangular coordinate system, where the horizontal axis of the two-dimensional rectangular coordinate system is the station number and the vertical axis is the time increasing downwards; in the construction progress time-distance diagram, multiple broken lines are used to represent the excavation trajectory of each working face and the secondary lining trajectory of each opposite through section, the slope of each broken line is determined by the advance speed of the segment through which the broken line passes, and the critical path control nodes are marked.

[0021] In this design, multiple polylines are drawn in a two-dimensional rectangular coordinate system with the station number as the horizontal axis and time as the vertical axis that increases downwards. The slope of each polyline directly reflects the advance rate of the corresponding segment, making the impact of changes in the surrounding rock on the construction progress visible. At the same time, critical path control nodes are marked, which makes it easier for construction managers to intuitively identify bottlenecks in the overall schedule and improves the readability of the simulation results and decision support capabilities.

[0022] Preferably, for all adjacent and opposing working faces within the global start and end chainage range, the steps of determining the dynamic breakthrough chainage and deriving the duration and completion node of the secondary lining process are performed one by one, and the critical path control nodes are output for all opposing breakthrough sections.

[0023] In this design, the method is extended from local extrapolation of a single pair of working faces to global solution of multiple working faces in the entire tunnel, fully capturing the spatiotemporal coupling relationship of all working faces in the entire tunnel, accurately screening out the critical path that restricts the overall project duration, ensuring the global integrity of the extrapolation results, and avoiding the omission of potential project duration bottlenecks.

[0024] On the other hand, to achieve the above objectives, the present invention provides a long tunnel multi-face construction period prediction system based on spatial optimization, characterized by comprising: a data verification module, used to acquire data and perform operations such as sorting by station number, comparing the end station number and starting station number of adjacent segments, interrupting the prediction and issuing an alarm, or determining the sorted data as a standardized geological feature set; a time consumption calculation module, used to store the correspondence between each surrounding rock type and the excavation advance rate and the lining advance rate, and to perform the operation of calculating the interval time for a given station number interval; and a breakthrough optimization module, used to receive specified information and determine the dominant... The system performs the following operations: setting the working face and buffer time offset, establishing a station search interval, taking the midpoint, calculating ΔT(m), updating the upper or lower bound of the station search interval according to the positive or negative value of ΔT(m), determining whether the length of the station search interval is less than 0.001 meters, and determining the dynamic breakthrough station; the lining simulation module is used to perform the following operations: taking the maximum excavation completion time as the trigger start time, calling the interval time in reverse accumulation along the direction from the dynamic breakthrough station to the lining endpoint, and obtaining the secondary lining duration and completion node; the results output module is used to perform the following operations: determining the critical path control node and outputting it.

[0025] In this design, by dividing the method into a data verification module, a time consumption calculation module, a through-lined optimization module, a lining simulation module, and a result output module, each step of the method is solidified into a software component with clearly defined functions. The interfaces of each module are clear, easy to maintain and upgrade, and easy to integrate into a tunnel construction management information system or BIM platform. It can efficiently handle the complex schedule simulation tasks of large-scale tunnel groups.

[0026] Thirdly, in order to achieve the above objectives, the present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the steps of the above method.

[0027] Compared with existing technologies, this invention has the following advantages: By constructing a standardized set of geological features and rigorously verifying the continuity of geological segment data, it can automatically detect and block errors such as gaps and overlaps in segment data before calculation, preventing problematic data from entering the subsequent extrapolation process. Based on this, the geological information is uniformly converted into time calculation parameters using the mapping relationship between surrounding rock type and drilling speed, and accurate time consumption calculation for arbitrary station intervals is achieved through segmented overlapping and accumulation, laying the foundation for quantitative analysis.

[0028] Unlike traditional simplified methods that divide the time into average speeds or total time, this method accurately maps complex and variable surrounding rock conditions into segments of advance speed. By repeatedly probing the zero point of the time difference equation containing buffer offsets using a bisection method, it automatically solves for the dynamic breakthrough station number until the calculation accuracy reaches a preset threshold (e.g., 0.001 meters). This allows for the acquisition of the dynamic breakthrough point where the difference in arrival time between two working faces equals the set buffer time offset (when the offset is zero, it is the natural meeting point). The solution process is deterministic and the results are reproducible.

[0029] By introducing a dominant working face strategy and a buffer time offset, the process can realistically simulate a construction arrangement where one side is stopped and the process is completed unidirectionally from the dominant working face. The lining time is accumulated backward from the completion time, achieving a tight connection between excavation and lining processes in the time dimension. Furthermore, by traversing each opposing completion section and automatically extracting the critical path control node with the latest completion time, the system automatically identifies global schedule bottlenecks under the complex spatiotemporal coupling relationship of multiple working faces throughout the entire tunnel. The method is logically rigorous and highly automated, providing accurate and quantifiable decision-making basis for construction organization design. Attached Figure Description

[0030] Figure 1 This is a flowchart illustrating the overall steps of a spatial optimization-based method for project duration estimation in long tunnels with multiple working faces, as described in this invention. Figure 2 This is a diagram illustrating the algorithm architecture for solving the dynamic through-chain station number using the bisection method described in this invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0032] This embodiment uses a long-distance water diversion tunnel project as an application scenario, combined with... Figure 1 The overall process shown illustrates the method for extrapolating the construction period of long tunnels with multiple working faces based on spatial optimization. For example... Figure 1As shown, the method sequentially includes steps S1 of acquiring and verifying geological segment data and generating a standardized geological feature set, steps S2 of establishing a segment set of advance speed and defining interval time, steps S3 of solving the dynamic breakthrough station number by binary search, steps S4 of reverse inference of secondary lining based on extreme value triggering, and steps S5 of identifying key path control nodes and outputting results.

[0033] It should be noted that the specific corresponding values ​​of the surrounding rock type and excavation advance rate and lining advance rate involved in the following embodiments, as well as the station number of each construction channel and the available tunnel entry time, are all exemplary values ​​selected for the purpose of illustration only, and do not constitute a limitation on the scope of protection of this invention.

[0034] Example 1 Step S1: Data Acquisition and Continuity Verification In this embodiment, the global starting and ending chainage of a long-distance water diversion tunnel is 0~10000m. The tunnel has two entry points: a first construction passage and an exit. The first construction passage intersects at chainage 5000m, with an available entry time of the third month. The exit intersects at chainage 10000m, with an available entry time of the fifth month. The input geological segmentation data includes two segments: the first segment starts at chainage 5000m, ends at chainage 7000m, and has a surrounding rock category of Class III; the second segment starts at chainage 7000m, ends at chainage 10000m, and has a surrounding rock category of Class IV.

[0035] After obtaining the above data, the geological segment data is sorted by station number from smallest to largest, and it is verified whether the end station number of the previous segment and the start station number of the next segment are equal. In this embodiment, the end station number of the first segment (7000m) is equal to the start station number of the second segment (7000m), and all adjacent segment pairs meet the equality condition, so no interruption is triggered, and the sorted geological segment data is determined as a standardized geological feature set.

[0036] To illustrate the blocking effect of the verification, two abnormal scenarios are given: First, if the end point of the first segment is recorded as 7000m and the start point of the second segment is recorded as 7050m, then there is a 50m gap between the two adjacent segments; Second, if the start point of the second segment is recorded as 6950m, then there is overlap between the two adjacent segments within the range of 6950m and 7000m. In both scenarios, there are adjacent segment pairs where the end point of the previous segment is not equal to the start point of the subsequent segment. Based on this, the method interrupts the deduction and issues an alarm, and does not execute subsequent steps, thereby detecting and blocking gaps or overlaps in the segment data before the deduction, preventing defective data from entering subsequent calculations.

[0037] Step S2: Establish a set of segmented advance speeds and define interval time. The pre-defined correspondence between different rock types and excavation and lining speeds is established. The exemplary correspondence used in this embodiment is as follows: for Class III rock, the excavation speed is 123.904779 m / month and the lining speed is 98.50 m / month; for Class IV rock, the excavation speed is 109.017283 m / month and the lining speed is 85.20 m / month.

[0038] Based on the above correspondence, the surrounding rock category of each segment in the standardized geological feature set is replaced with the corresponding excavation advance rate and lining advance rate to obtain the advance rate segment set, namely: the chainage interval [5000, 7000] corresponds to an excavation advance rate of 123.904779 m / month and a lining advance rate of 98.50 m / month; the chainage interval [7000, 10000] corresponds to an excavation advance rate of 109.017283 m / month and a lining advance rate of 85.20 m / month.

[0039] The time taken for any station interval is defined as follows: calculate the overlap length between the station interval and each segment in the set of advance speed segments, divide each overlap length by its corresponding advance speed, and then sum them. For example, when calculating the time taken for excavation from station 5000m to station 7500m of the first construction passage intersection, the overlap length between the interval [5000, 7500] and segment [5000, 7000] is 2000m, corresponding to an excavation advance speed of 123.904779m / month, and the overlap length with segment [7000, 10000] is 500m, corresponding to an excavation advance speed of 109.017283m / month. Therefore, the time taken for this interval is 2000÷123.904779+500÷109.017283=16.14+4.59=20.73 months.

[0040] Step S3: Binary solution for dynamic connection station number See Figure 2 The algorithm architecture for solving the dynamic breakthrough station number using the bisection method is shown. In this embodiment, adjacent and opposing first and second working faces are selected: the first working face corresponds to the first construction passage, and its starting station number is st. L =5000m, start time t L The third month; the second working face corresponds to the aforementioned exit, its starting station number st. R =10000m, start time t R This is the 5th month. The first working face is excavating from station 5000m in the direction of increasing station, and the second working face is excavating from station 10000m in the direction of decreasing station.

[0041] Upon receiving specified information, a dominant working face is determined from the first and second working faces based on the specified information, and a buffer time offset (Offset) is set for the dominant working face. This embodiment first illustrates the solution process for the natural meeting point with Offset=0. The influence of the dominant working face strategy on the dynamic breakthrough station number is specifically explained in Embodiment 2.

[0042] With st L =5000m is the lower bound, st R =10000m is used as the upper limit to establish the chainage search interval. The midpoint is taken as the trial breakthrough chainage m. The time difference value ΔT(m) is calculated according to the following formula: ΔT(m)=[t L +f(st L ,m)]–[t R +f(st R, m)]–Offset Where f(stL,m) is the excavation time from station 5000m to the test breakthrough station m, calculated according to the aforementioned interval time definition. R ΔT(m) represents the time taken to excavate the section from chainage 10000m to the test breakthrough chainage m. When ΔT(m) > 0, it indicates that the first working face reaches the test breakthrough chainage m late, and the upper boundary of the search interval is updated to m; when ΔT(m) < 0, the lower boundary of the search interval is updated to m; the midpoint of the updated interval is taken as the new test breakthrough chainage m, and ΔT(m) is recalculated. This process is repeated until the length of the search interval is less than 0.001 meters.

[0043] The iterative process in this embodiment is as follows (excavation advance rate is taken as 123.904779 m / month for Class III surrounding rock and 109.017283 m / month for Class IV surrounding rock): First, the midpoint m = 7500.00 m is taken, ΔT(m) = –4.204 months, which is less than 0, so the lower bound is updated to 7500.00 m; Second, the midpoint m = 8750.00 m is taken, ΔT(m) = +18.728 months, which is greater than 0, so the upper bound is updated to 8750.00 m; Third, the midpoint m = 8125.00 m is taken, ΔT(m) = +7.262 months, and the upper bound is updated... Upper bound; 4th iteration: midpoint m = 7812.50m, ΔT(m) = +1.529 months, upper bound updated; 5th iteration: midpoint m = 7656.25m, ΔT(m) = -1.338 months, lower bound updated; 6th iteration: midpoint m = 7734.38m, ΔT(m) = +0.095 months, upper bound updated; After this, the binary search continues, and after a total of 23 iterations, the search interval length converges to less than 0.001 meters. The test breakthrough station number at this point is determined as the dynamic breakthrough station number m* = 7729.17m between the first and second working faces. The time t for the first working face to reach this station number is then determined. L+f(st L (m*) and the time t when the second working face reaches that station. R +f(st R Both m and m* are the 25th and 83rd month, and the difference between their arrival times is equal to the set buffer time offset (zero in this embodiment).

[0044] It should be noted that when the first working face advances in the direction of increasing station number, it successively traverses Class III surrounding rock sections [5000, 7000] and Class IV surrounding rock sections [7000, 7729.17], while the second working face only advances within the Class IV surrounding rock section [7729.17, 10000]. Due to the abrupt change in surrounding rock type along the route, resulting in different advance speeds on both sides, the dynamically connected station number 7729.17m is not equal to the geometric midpoint 7500m of the two construction channels. This demonstrates the spatial optimization capability of this method compared to the simplified method of calculating the meeting position by equalizing the average speed or total time.

[0045] Step S4: Backward deduction of secondary lining based on extreme value triggering For the opposing penetration section defined by the dynamically connected chainage 7729.17m, the maximum value between the excavation completion time of the first working face and the excavation completion time of the second working face is taken as the trigger start time for the secondary lining process of the opposing penetration section. In this embodiment, both working faces reach the dynamically connected chainage in the 25th and 83rd months, therefore, the trigger start time for the secondary lining process of the opposing penetration section is the 25th and 83rd months.

[0046] Taking the dynamic connection chainage of the opposing through section 7729.17m as the lining starting point, and taking the first construction channel intersection chainage of the first working face 5000m and the exit intersection chainage of the second working face 10000m as the lining ending point, starting from the 25.83rd month, the time consumed in the section is accumulated in reverse order from the lining starting point to the lining ending point.

[0047] Towards the first construction passage, the lining section [5000, 7729.17] is divided into Class IV surrounding rock sub-sections [7000, 7729.17] and Class III surrounding rock sub-sections [5000, 7000] according to the segment boundaries. The lining duration is 729.17 ÷ 85.20 + 2000 ÷ 98.50 = 8.56 + 20.30 = 28.86 months, with a completion date of 25.83 + 28.86 = 54.69 months. Towards the exit, the lining section [7729.17, 10000] is in Class IV surrounding rock, with a lining duration of 2270.83 ÷ 85.20 = 26.65 months, and a completion date of 25.83 + 26.65 = 52.48 months. Thus, the duration and completion date of the secondary lining process for this opposing through section are obtained.

[0048] The reverse accumulation of the secondary lining process automatically calls up the interval time segment by segment along the space, so that the lining simulation fully reflects the influence of the surrounding rock change on the lining advance speed in the same opposite through section; the direction of the reverse accumulation (pushing back from the dynamic through pile number to the direction of the construction channel) is consistent with the construction spatiotemporal logic of the secondary lining pouring from the through position to the outside.

[0049] Step S5: Identification of Critical Path Control Nodes and Output of Results Based on the excavation completion milestones of each working face and the secondary lining completion milestones of each opposing through section, the milestone with the latest completion time is determined as the critical path control node. In the case of only a single opposing through section, the excavation completion milestones are in the 25.83rd month, and the secondary lining completion milestones are in the 54.69th month and 52.48th month, respectively. Therefore, the secondary lining completion milestone corresponding to the 54.69th month, in the direction of the first construction passage, is determined as the critical path control node, and its completion time is output.

[0050] Furthermore, a one-dimensional process data table can be output, which lists the starting station number, start time, and completion time of each working face excavation process in rows, as well as the starting and ending station numbers, trigger start time, and completion time of each opposite through section secondary lining process. The one-dimensional process data representation of this embodiment is as follows: First working face excavation process, starting at chainage 5000m, start time in the 3rd month, completion time in the 25.83rd month; Second working face excavation process, starting at chainage 10000m, start time in the 5th month, completion time in the 25.83rd month; Secondary lining process towards the first construction passage, starting and ending at chainage 7729.17m to 5000m, start time in the 25.83rd month, completion time in the 54.69th month; Secondary lining process towards the exit, starting and ending at chainage 7729.17m to 10000m, start time in the 25.83rd month, completion time in the 52.48th month.

[0051] Furthermore, a construction progress time-distance diagram can be generated. The construction progress time-distance diagram adopts a two-dimensional rectangular coordinate system, with the horizontal axis representing the station number and the vertical axis representing the time increasing downwards. In the construction progress time-distance diagram, multiple broken lines represent the excavation trajectory of each working face and the secondary lining trajectory of each opposite through section. The slope of each broken line is determined by the advance speed of the segment through which the broken line passes, and the critical path control nodes are marked to intuitively reflect the impact of changes in the surrounding rock on the construction progress and indicate the overall schedule bottleneck.

[0052] Example 2 (The Influence of the Offset of the Main Working Face and Buffer Time on the Dynamic Piling) This embodiment illustrates the setting direction of the buffer time offset and its impact on the dynamic connection station, corresponding to the offset direction defined in claim 2. To clearly demonstrate the causal relationship, simplified parameters are used in this embodiment.

[0053] Let the starting station number of the first working face be st. L =0m, starting station of the second working face st R =10000m, both started at the same time (t) L =t R Furthermore, both tunnels traversed sections with the same surrounding rock type and excavation speed of v (in this embodiment, v = 100 m / month).

[0054] When Offset = 0, the time difference equation ΔT(m) = [t L +f(st L ,m)]–[t R +f(st R The degenerates to (m–0) / v–(10000–m) / v=0, and the bisection solution yields the dynamic connection station number m=5000m, which means that the natural meeting point of the two working faces is exactly the geometric midpoint.

[0055] The first working face is designated as the dominant working face, and a positive buffer time offset, Offset, is assigned to it. The time difference equation is (m–0) / v–(10000–m) / v–Offset=0, which simplifies to m=5000+Offset·v / 2. It can be seen that when Offset is positive, the dynamic breakthrough station m is greater than 5000m, and relative to the breakthrough station 5000m when Offset is zero, it shifts in the direction of increasing station number, i.e., away from the direction of the first working face as the dominant working face. For example, when Offset=2 months, m=5100m; when Offset=5 months, m=5250m; and when Offset=10 months, m=5500m. The dynamic breakthrough station further deviates from the dominant working face as Offset increases.

[0056] The above-mentioned offset corresponds to the following construction practice in engineering: When two working faces tunneling in opposite directions are close to breakthrough, according to construction safety requirements, one of them must be stopped and the other side should tunnel through the last section in one direction. After designating the working face undertaking the unidirectional breakthrough section as the leading working face and using Offset to represent the buffer time required for its unidirectional breakthrough, the dynamic breakthrough station number deviates from the leading working face, which means that the leading working face undertakes a longer tunneling section, so that the deduction result is consistent with the construction arrangement of "stopping one side and tunneling through the leading working face in one direction".

[0057] Regarding the engineering basis for the Offset value, this embodiment further explains as follows: According to the construction safety requirements for excavation in opposite directions, when the distance between two opposing working faces is less than a certain safe distance (e.g., less than 30 meters or less than 5 times the tunnel diameter), personnel and equipment on both sides should be evacuated; when the distance is further reduced to, for example, 15 meters, one side should stop, and the other side should excavate in one direction to complete the last section. The buffer time offset Offset corresponds to the amount of time required for the main working face to complete the safe step section in one direction. Its typical value can be equivalent to about one month's time difference, and can be specifically set by the user according to the tunnel diameter, surrounding rock conditions, and safety regulations.

[0058] It should be noted that in this embodiment, the dominant working face is determined by the received designated information. This method does not impose a fixed limitation on the identity of the dominant working face. Users can flexibly designate the first working face or the second working face as the dominant working face according to the actual conditions of each construction channel.

[0059] Example 3 (Traversal and deduction of global multi-directional through-interval) This embodiment illustrates the method of sequentially tracing all adjacent and opposing working faces within the global start and end station range, corresponding to claim 8.

[0060] When the tunnel has multiple construction channels arranged along the axis, thus forming multiple opposing excavation working faces, for all adjacent and opposing excavation working faces within the global start and end chainage range, the steps described in Example 1 for determining the dynamic connection chainage (step S3) and for deduce the duration and completion node of the secondary lining process (step S4) are executed one by one, thereby obtaining the dynamic connection chainage of each opposing connection section, the excavation completion node of each working face, and the secondary lining completion node of each opposing connection section.

[0061] Subsequently, the node with the latest completion time among all excavation completion nodes and all secondary lining completion nodes is identified as the critical path control node for the entire tunnel, and its completion time is output. Thus, the method extends from local extrapolation to a global solution for multiple working faces throughout the entire tunnel, fully capturing the spatiotemporal coupling relationships of all working faces, accurately identifying the critical path that constrains the overall project duration, and avoiding the omission of potential schedule bottlenecks.

[0062] The derivation of each opposite through section is independent of each other. The dynamic through station number, lining start point and lining end point are determined separately according to the method described in Example 1. The values ​​will not be listed one by one here.

[0063] System Implementation Examples The present invention also provides a spatial optimization-based long tunnel multi-face construction period prediction system corresponding to the above method, including a data verification module, a time consumption calculation module, a breakthrough optimization module, a lining prediction module, and a result output module.

[0064] The data verification module is used to obtain the global start and end station numbers, the intersection station numbers of each construction channel and the available tunnel entry time, and the geological segment data. It performs the following operations: sorting by station number, comparing the end station number and start station number of adjacent segments, interrupting the simulation and issuing an alarm when there are unequal adjacent segment pairs, and determining the sorted data as a standardized geological feature set when all are equal. That is, it performs the operation described in step S1.

[0065] The time consumption calculation module is used to store the correspondence between each surrounding rock type and the excavation advance speed and the lining advance speed, and to perform the operation of calculating the interval time of a given station interval, that is, to perform the operation described in step S2.

[0066] The through-connection optimization module is used to perform the following operations: receiving specified information to determine the dominant working face and setting the buffer time offset Offset, establishing the station number search interval, taking the midpoint, calculating ΔT(m), updating the upper or lower boundary of the station number search interval according to the positive or negative of ΔT(m), determining whether the length of the station number search interval is less than 0.001 meters, and determining the dynamic through-connection station number, that is, performing the operations described in step S3.

[0067] The lining simulation module is used to perform the following operations: taking the maximum excavation completion time as the trigger start time, calling the interval time in reverse accumulation along the direction from the dynamic connection station to the lining end point, and obtaining the secondary lining duration and completion node, i.e., performing the operation described in step S4.

[0068] The output module is used to perform the operation of determining and outputting the critical path control nodes, that is, to perform the operation described in step S5.

[0069] The aforementioned modules can be implemented using computer programs, hardware, or a combination of hardware and software with corresponding data processing capabilities. The modules exchange data such as the standardized geological feature set, the segmented advance speed set, the dynamic breakthrough station number, the trigger start time, and the completion node through data interfaces. The system can be integrated into a tunnel construction management information system or a building information modeling platform.

[0070] Examples of electronic devices and storage media The method described in this invention can be implemented by an electronic device, which includes a memory and a processor. The memory stores a computer program that can run on the processor. When the processor executes the computer program, it implements the steps of the method described in any of the above embodiments.

[0071] The present invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the method described in any of the above embodiments. The computer-readable storage medium includes, but is not limited to, media capable of storing program code such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0072] The specific values ​​for advance rate, station number, available tunneling time, and buffer time offset in the above embodiments are exemplary values ​​selected for ease of explanation and do not constitute a limitation on the scope of protection of this invention. Those skilled in the art can adjust the above parameters accordingly based on the geological segmentation, construction access layout, and safety regulations of the actual project.

[0073] The order of steps in the method described in this invention can be appropriately adjusted without contradiction, and some operations in each step can be combined or split. The above description is only a preferred embodiment of this invention and is not intended to limit this invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A method for project duration estimation of long tunnels with multiple working faces based on spatial optimization, characterized in that, include: Obtain the global start and end station numbers of the tunnel, the intersection station numbers of each construction passage and the available entry time, as well as geological segment data including the start and end station numbers of each segment and the surrounding rock type; The geological segment data is sorted by station number, and the end station number of the previous segment and the start station number of the next segment are checked to see if they are equal. If there are unequal adjacent segment pairs, the simulation is interrupted and an alarm is issued, and subsequent steps are not executed. If they are all equal, the sorted geological segment data is determined as a standardized geological feature set. Based on the preset correspondence between the surrounding rock type and the excavation and lining speeds, the surrounding rock type of each segment in the standardized geological feature set is replaced with the corresponding speed to obtain the speed segment set; the interval time of any station interval is defined as: the sum of the overlap length between the interval and each speed segment divided by the corresponding speed. Select the first and second working faces that are adjacent and excavating in opposite directions, and obtain their starting station number st respectively. L Start time t L and starting station number st R Start time t R ; Receive specified information to determine a dominant working face from the two, and set a buffer time offset for the dominant working face; With st L for lower bound, st R Establish a search interval for the upper limit of the chainage, take the midpoint as the trial breakthrough chainage m, and calculate the time difference value ΔT(m) according to the following formula: ΔT(m)=[t L +f(st L ,m)]–[t R +f(st R ,m)]–Offset In the formula f(st L ,m),f(st R m) are the values ​​obtained according to the interval time definition, respectively. L To m, from st R The interval time up to m; Offset is the buffer time required for the dominant working face when one of the two opposing working faces stops and the dominant working face breaks through in one direction; When ΔT(m)>0, update the upper bound of the search interval to m; when ΔT(m)<0, update the lower bound of the search interval to m. Take the midpoint of the updated interval as the new m and recalculate ΔT(m). Repeat the above update and calculation until the length of the search interval is less than 0.001 meters. Then, determine the m at this time as the dynamic connection station number between the first working face and the second working face. For opposing interconnected sections defined by the dynamic interconnected station number, the maximum value between the excavation completion time of the first and second working faces is taken as the trigger start time for the secondary lining process of the opposing interconnected section. Taking the dynamic connection chainage of the opposite through section as the lining start point and the construction channel intersection chainage corresponding to the first or second working face as the lining end point, starting from the start time, the interval time is called in reverse along the direction from the lining start point to the lining end point, and the duration and completion node of the secondary lining process are obtained. Based on the excavation completion nodes of each working face and the secondary lining completion nodes of each opposite through section, the node with the latest completion time is determined as the critical path control node and its completion time is output.

2. The method for project duration estimation of long tunnels with multiple working faces based on spatial optimization according to claim 1, characterized in that, When Offset is positive, the dynamic breakthrough station number is offset from the breakthrough station number when Offset is zero, in the direction away from the dominant working face.

3. The method for project duration estimation of long tunnels with multiple working faces based on spatial optimization according to claim 1, characterized in that, The time consumption of each interval is accumulated in reverse order, including: along the direction from the dynamic through-lined station to the lining end point, the station range from the lining start point to the lining end point is divided into multiple continuous sub-intervals according to the segment boundary of the segment set of the advance speed. For each sub-interval, the length of the sub-interval is divided by the lining advance speed corresponding to the sub-interval to obtain the lining time of the sub-interval. The lining time of each sub-interval is accumulated in sequence.

4. The method for project duration estimation of long tunnels with multiple working faces based on spatial optimization according to claim 1, characterized in that, The lining starting point can be replaced with one of the following: the physical midpoint station of the opposite through section, the dynamic through station, or an externally input custom station.

5. The method for project duration estimation of long tunnels with multiple working faces based on spatial optimization according to claim 1, characterized in that, The interval time is calculated as follows: For any input station interval [a,b], extract all the advance speed segments that overlap with the station interval [a,b] from the advance speed segment set. Divide the intersection length of each overlapping segment with [a,b] by the advance speed corresponding to the overlapping segment to obtain the segment time. Then, sum up all the segment times and output them.

6. The method for project duration estimation of long tunnels with multiple working faces based on spatial optimization according to claim 1, characterized in that, Also includes: Output a one-dimensional process data table. The one-dimensional process data table lists the starting station number, start time, and completion time of the excavation process of each working face in rows, as well as the starting and ending station numbers, trigger start time, and completion time of the secondary lining process of each opposite through section.

7. The method for project duration estimation of long tunnels with multiple working faces based on spatial optimization according to claim 6, characterized in that, It also includes: generating a construction progress time-distance diagram in a two-dimensional rectangular coordinate system, where the horizontal axis of the two-dimensional rectangular coordinate system is the station number and the vertical axis is the time increasing downwards; in the construction progress time-distance diagram, multiple broken lines are used to represent the excavation trajectory of each working face and the secondary lining trajectory of each opposite through section, and the slope of each broken line is determined by the advance speed of the segment through which the broken line passes, and the critical path control nodes are marked.

8. The method for project duration estimation of long tunnels with multiple working faces based on spatial optimization according to claim 1, characterized in that, For all adjacent and opposing working faces within the global start and end chainage range, the steps of determining the dynamic breakthrough chainage and deriving the duration and completion node of the secondary lining process are executed one by one, and the critical path control nodes are output for all opposing breakthrough sections.

9. A system for project duration estimation for long tunnels with multiple working faces based on spatial optimization, characterized in that, include: The data verification module is used to acquire data and perform operations such as sorting by station number, comparing the end station number and start station number of adjacent segments, interrupting the simulation and issuing an alarm, or determining the sorted data as a standardized geological feature set. The time consumption calculation module is used to store the correspondence between each surrounding rock type and the excavation advance rate and lining advance rate, and perform operations to calculate the interval time of a given station number interval. The breakthrough optimization module is used to perform operations such as receiving specified information to determine the dominant working face and setting the buffer time offset, establishing the station number search interval, taking the midpoint, calculating ΔT(m), updating the upper or lower boundary of the station number search interval according to the positive or negative of ΔT(m), determining whether the length of the station number search interval is less than 0.001 meters, and determining the dynamic breakthrough station number. The lining simulation module is used to perform operations such as taking the maximum excavation completion time as the trigger start time, calling the interval time in reverse accumulation along the direction from the dynamic breakthrough station number to the lining end point, and obtaining the secondary lining duration and completion node. The result output module is used to perform operations to determine the critical path control node and output it.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as claimed in any one of claims 1 to 8.

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