Method for controlling the impact of tunnel opening construction in broken rock geology on adjacent tunnel openings

Abstract

The present invention provides a method for controlling the impact of broken rock geological tunnel entrance construction on adjacent tunnel entrances, including setting a monitoring section, obtaining section monitoring results, analyzing the section monitoring results and achieving the control purpose. It has better safety and comprehensiveness and can be widely used in the field of tunnel construction.

Description

Technical Field

[0001] The invention relates to a method for controlling the influence of broken rock geological tunnel opening construction on adjacent tunnel openings, and is applicable to the field of tunnel construction. Background Art

[0002] Tunnel portal construction under broken rock geological conditions faces many technical challenges. Due to the fragmentation of the rock mass, the construction process may cause surface settlement, portal deformation, and even damage to adjacent tunnel structures. These risk factors seriously affect construction safety and project quality. Although traditional construction methods, such as drilling and blasting, are less expensive in some cases, they cause greater disturbance to the surrounding rock mass and can easily lead to stability problems at adjacent portals. Therefore, the development and application of more advanced control technologies to minimize the impact of construction on adjacent portals has become a research hotspot in the field of tunnel engineering.

[0003] In recent years, with the technological progress in the field of tunnel engineering, a series of innovative construction methods and control technologies have emerged. For example, the use of prestressed anchors and grouting reinforcement technology can significantly improve the stability of broken rock masses and reduce the adverse effects on adjacent tunnel openings during construction. In addition, by implementing dynamic design and construction monitoring, the rock mass response during construction can be evaluated in real time, and the construction plan can be adjusted in time to ensure construction safety and project quality.

[0004] In terms of the impact on adjacent tunnel openings during the construction of the broken rock geological tunnel opening, the current main practice in the industry is to set up monitoring points at the adjacent tunnel openings, such as the vault settlement monitoring point and the surrounding convergence monitoring line. However, these methods have serious problems. The process of deformation caused by the adjacent tunnel opening is a complex reaction process. It is easy to "miss detection" the deformation of the adjacent tunnel opening by only doing a little "point" or "line" monitoring, and it cannot truly reflect the deformation impact of the adjacent tunnel opening. Therefore, there is an urgent need for a comprehensive control method that can fully reflect the impact of the construction of the broken rock geological tunnel opening on the adjacent tunnel opening. Summary of the invention

[0005] The purpose of the present invention is to solve the current urgent need for a comprehensive control method that can fully reflect the impact of broken rock geological tunnel opening construction on adjacent tunnel openings. Therefore, a control method for the impact of broken rock geological tunnel opening construction on adjacent tunnel openings is proposed.

[0006] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0007] The steps of the method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings are as follows:

[0008] S101, setting monitoring section;

[0009] The setting of monitoring sections includes setting n monitoring sections at a certain interval along the tunnel axis direction near the tunnel opening before the construction of the broken rock geological tunnel opening, which is represented by A i , i = 1 to n;

[0010] S102, obtaining cross-section monitoring results;

[0011] The cross-section monitoring results are obtained by, during the construction of the broken rock geological tunnel entrance, using three-dimensional laser scanning technology to scan each monitoring section A at a certain time interval. i The scanning results of m inner contour sections are obtained in sequence, and sorted into a data set according to the acquisition time. i The obtained inner contour cross-section scanning results are expressed as the cross-section scanning result set C i = {P ij |j=1,2,...m}, where P ij is the j-th cross-sectional scanning result of the i-th section;

[0012] S103, analysis of cross-section monitoring results;

[0013] The section monitoring results analysis includes the following: i The obtained inner contour cross-section scanning results are expressed as the cross-section scanning result set C i = {P ij |j=1,2,...m} for comparative analysis, and obtain the monitoring section A i The cross-section coincidence rate series data set D i = {B ik |k=2,3,...m};

[0014] S104, realization of control objectives;

[0015] The realization of the control purpose includes obtaining the monitoring section A i The cross-section coincidence rate series data set D i Analyze the data and obtain monitoring section A i The predicted value of the overlap rate B i(m+1) , and combined with the early warning standards, the monitoring section A i The stability of the system is evaluated and corresponding response measures are implemented according to the evaluation results to achieve the purpose of control.

[0016] Furthermore, in the above S102, the method for obtaining m inner contour line section scanning results for each monitoring section based on the three-dimensional laser scanning technology is as follows: for section A i , set the fixed tunnel section scanner position unchanged, and scan the current section A at a certain time intervali Perform inner contour line section scanning to obtain m inner contour line section scanning results.

[0017] Furthermore, in the above S103, the comparative analysis step is:

[0018] a) Obtain monitoring section D i The inner contour line section scanning result is expressed as the section scanning result set C i = {P ij |j=1,2,...m},

[0019] b) Calculating the cross-sectional scanning result set C i The cross-sectional overlap rate of adjacent data B ik , the calculation formula is formula (1),

[0020]

[0021] In the formula, B ik For the set C i Medium i(k-1) With P i(k) The cross-sectional overlap ratio between the k-1,k P is the cross-sectional scanning result i(k-1) The cross-sectional scan results P i(k) The overlap area between them, S k-1 P is the cross-sectional scanning result i(k-1) The calculated value of the cross-sectional scanning area,

[0022] Furthermore, the overlap area S k-1,k The acquisition method is as follows: a) for the cross-sectional scanning result P i(k-1) The cross-sectional scan results P i(k) , combined with the placement information of the instrument when obtaining the scanning results, draw the building boundary lines respectively, b) convert the cross-sectional scanning results P i(k-1) The cross-sectional scan results P i(k) According to the building limit line, the area of ​​the overlapping area is calculated as S k-1,k .

[0023] c) After obtaining the calculation results according to formula (1), for section A i , sort out and obtain the monitoring section A i The cross-section coincidence rate series data set D i = {B ik |k=2,3,...m}.

[0024] Furthermore, in the above S104, the monitoring section A is obtained i The predicted value of the overlap rate B i(m+1) The steps are: a) obtaining the monitoring section Ai The cross-section coincidence rate series data set D i = {B ik |k=2,3,...m}, b) for the data section A i The data of the cross-section coincidence rate sequence data set are normalized, and c) the data cross section A is i The invention discloses a method for preparing a cross-sectional overlap rate sequence data set, comprising: dividing the data of the cross-sectional overlap rate sequence data set into a training set and a test set; d) constructing a long short-term memory neural network prediction model; f) using the training set to train the prediction model to obtain a trained prediction model; g) using the test set to test and adjust the trained prediction model to finally obtain a complete prediction model; and h) using the complete prediction model to predict the next data of the sequence data to obtain a prediction value Bi(m+1).

[0025] The beneficial effects of the present invention are:

[0026] The present invention utilizes three-dimensional laser scanning technology to accurately obtain the scanning results of the inner contour line of the tunnel section, and through data analysis, understands the changes of the tunnel section in real time, and provides accurate data support for construction; through the analysis and prediction of the section overlap rate sequence data set, the stability change trend of the tunnel section can be predicted, and combined with the early warning standards, early warning of potential risks can be achieved, providing protection for construction safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 : Flow chart of the method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings of the present invention;

[0028] Figure 2 : The monitored value and predicted value of the overlap rate of the monitoring section A1 of the embodiment of the present invention. DETAILED DESCRIPTION

[0029] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings; it should be understood that the specific embodiments given here are only used to illustrate and explain the present invention and cannot be used to limit the present invention.

[0030] The following is a specific embodiment of a method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings.

[0031] like Figure 1 Shown is a flow chart of a method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings according to the present invention.

[0032] A method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings, characterized in that the method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings comprises the following steps:

[0033] S101, setting monitoring section;

[0034] The setting of monitoring sections includes setting n monitoring sections at certain intervals along the tunnel axis direction adjacent to the tunnel opening before the construction of the broken rock geological tunnel opening, expressed as Ai, i=1~n;

[0035] In this embodiment, the actual project is the construction project of the Taohualing Tunnel Portal of the XMSG-2 section of the Jiaozuo to Pingdingshan Expressway Xingyang to Xinmi section. The Taohualing Tunnel is designed to be separated with a net distance of 27m. The starting and ending points of the left line are ZK27+301~ZK29+983, with a length of 2682m, and the starting and ending points of the right line are YK27+308~YK30+015, with a length of 2707m. The tunnel entrances are both end wall portals, and the lengths of the left and right open tunnels are both 5m. The temporary slope of the left tunnel is 1:0.3, and the slope of the tunnel surface is 1:0.1. Sprayed anchor protection is used for slope protection; the temporary slope of the right tunnel is 1:0.5, and the slope of the tunnel surface is 1:0.1. Sprayed anchor protection is used for slope protection; the permanent side slopes of the left and right tunnels have two types: 1:0.5 and 1:0.75, and frame anchors and grass planting are used for slope protection.

[0036] In this embodiment, the geological conditions of the entrance section of the tunnel are as follows: the upper part of the entrance section is a slightly dense gravel soil layer of about 1 to 2 meters thick; below it is a medium-thick layer of strongly to moderately weathered dolomite, limestone intercalated with thin layers of marl, etc. The weathering layer is relatively thick, the rock mass is broken to relatively broken, but the weak intercalated rock mass presents a fragmented stone-like fragmented structure, and the local medium weathering presents a block mosaic structure. The rock layer has an incidence of 6°∠17°. A group of shear joints are developed, with an incidence of 212°∠76°, a spacing of about 30cm, and a general density, mostly closed to slightly open. The slope is mainly composed of medium-thick layers of strongly to moderately weathered limestone, dolomite intercalated with thin layers of marl and mudstone, with strong weathering, local cracks developed, a fragmented stone-like fragmented structure, general structural surface bonding, and a relatively broken rock mass. According to the rock slope rock mass type classification, it is classified as Class IV. The main controlling structural surface of the tunnel entrance slope is the layer and micro-cracks. The rock formation inclination intersects the left and right slopes at a large angle, which is a tangent slope and a basically stable structure. The wedge-shaped body of the occurrence-joint combination is located outside the slope line and is a relatively stable structure. The natural slope intersects the rock formation inclination at a small angle, which is a bedding slope and is not stable. It is relatively stable at present, and there is a possibility of landslides under strong disturbance. The rock formation occurrence and joint combination wedge-shaped body are located outside the slope range. Due to the fragmentation of the rock mass, excessive slope cutting can easily cause local landslides and rockfalls.

[0037] In this embodiment, the left entrance of the tunnel enters the tunnel on April 20, 2023, and the specific entry time of the right entrance is June 29, 2023. Therefore, when the right tunnel of the tunnel in this embodiment begins to enter the tunnel, a monitoring section is set in the left tunnel of the tunnel at an interval of 5m. A total of 8 monitoring sections are set, marked as A1 to A8;

[0038] S102, obtaining cross-section monitoring results;

[0039] The obtaining of section monitoring results includes, during the construction of the broken rock geological tunnel entrance, obtaining m inner contour section scanning results for each monitoring section Ai in sequence based on the three-dimensional laser scanning technology at certain time intervals, and sorting and organizing them into a data set in sequence according to the acquisition time, and the inner contour section scanning results obtained for the monitoring section Ai are expressed as a section scanning result set Ci={Pij|j=1,2,...m}, wherein Pij is the jth scanning result of the ith section; further, in the above S102, the method for obtaining m inner contour section scanning results for each monitoring section based on the three-dimensional laser scanning technology is as follows: for section Ai, the position of the fixed tunnel section scanner is set unchanged, and the inner contour section scanning of the current section Ai is performed at certain time intervals to obtain m inner contour section scanning results.

[0040] In this embodiment, we perform inner contour line section scanning results for each monitoring section A1-A8 at a fixed time interval, obtain 30 inner contour line section scanning results for each monitoring section Ai based on the three-dimensional laser scanning technology at a certain time interval, and sort them into a data set in sequence according to the acquisition time. The inner contour line section scanning results obtained by the monitoring section Ai are expressed as a section scanning result set Ci={Pij|j=1,2,...30}. The three-dimensional laser scanner used for the inner contour line section scanning is shown in Table 1.

[0041] Table 1 Parameters of 3D laser scanner

[0042] project content brand Trimble Technical Parameters Point cloud quantity Range 0.6m~80m Ranging noise 2mm Distance measurement accuracy 2mm Field of view 360°*292° Resolution 3840×2746

[0043] S103, analysis of cross-section monitoring results;

[0044] The cross-section monitoring result analysis includes comparing and analyzing the inner contour line cross-section scanning results obtained from the monitoring cross-section Ai, expressed as a cross-section scanning result set Ci={Pij|j=1,2,...m}, to obtain a cross-section coincidence rate sequence data set Di={Bik|k=2,3,...m} of the monitoring cross-section Ai;

[0045] Furthermore, the comparative analysis steps are:

[0046] a) Obtain the inner contour line section scanning result of the monitoring section Di, which is expressed as the section scanning result set Ci = {P ij |j=1,2,...m},

[0047] b) Calculate the cross-sectional overlap ratio Bik of adjacent data of the cross-sectional scanning result set Ci, using the following formula (1):

[0048]

[0049] Wherein, Bik is the cross-sectional overlap rate between Pi(k-1) and Pi(k) in the set Ci, Sk-1,k is the overlap area between the cross-sectional scanning result Pi(k-1) and the cross-sectional scanning result Pi(k), Sk-1 is the calculated cross-sectional scanning area of ​​the cross-sectional scanning result Pi(k-1),

[0050] Furthermore, the method for obtaining the overlap area Sk-1,k is as follows: a) for the cross-sectional scanning result Pi(k-1) and the cross-sectional scanning result Pi(k), in combination with the placement information of the instrument when the scanning result is obtained, the building boundary line is drawn respectively; b) the cross-sectional scanning result Pi(k-1) and the cross-sectional scanning result Pi(k) are superimposed according to the building boundary line, and the area of ​​the overlap area is calculated as Sk-1,k. c) after obtaining the calculation result according to formula (1), for the cross-sectional Ai, the cross-sectional overlap rate sequence data set Di={Bik|k=2,3,...m} of the monitoring cross-sectional Ai is sorted and obtained.

[0051] In this embodiment, taking section A1 as an example, the section monitoring data Ci={Pij|j=1,2,...30} is obtained for comparative analysis and calculation to obtain the section coincidence rate sequence data set D1={95.13, 95.63, 95.68, 95.92, 95.75, 95.63, 95.82, 95.86, 95.91, 95.99, 96.08, 96.15, 96.31, 96.52, 96.34, 96.22, 96.25, 96.31, 96.42, 96.39, 96.46, 96.24, 96.85, 97.09, 96.88, 96.89, 97.05, 97.02, 97.12}

[0052] S104, realization of control objectives;

[0053] The realization of the control purpose includes performing data analysis on the section overlap rate sequence data set Di of the monitoring section Ai, obtaining the predicted value Bi(m+1) of the overlap rate of the monitoring section Ai, and evaluating the stability of the monitoring section Ai in combination with the early warning standard, and implementing corresponding response measures according to the evaluation results to achieve the control purpose.

[0054] Furthermore, in the above S104, the step of obtaining the predicted value Bi(m+1) of the overlap rate of the monitoring section Ai is: a) obtaining the section overlap rate sequence data set Di={Bik|k=2,3,...m} of the monitoring section Ai, b) performing data normalization on the data of the section overlap rate sequence data set of the data section Ai, c) dividing the data of the section overlap rate sequence data set of the data section Ai into a training set and a test set, d) constructing a long short-term memory neural network prediction model, f) using the training set to train the prediction model to obtain a trained prediction model, g) using the test set to test and adjust the trained prediction model to finally obtain a complete prediction model, and h) using the complete prediction model to predict the next data of the sequence data to obtain a predicted value Bi(m+1).

[0055] In this embodiment, according to the obtained section overlap rate sequence data set D1 = {95.13, 95.63, 95.68, 95.92, 95.75, 95.63, 95.82, 95.86, 95.91, 95.99, 96.08, 96.15, 96.31, 96.52, 96.34, 96.22, 96.25, 96.31, 96.42, 96.39, 96.46, 96.24, 96.85, 97.09, 96.88, 96.89, 97.05, 97.02, 97.12}, data analysis is performed to obtain a predicted value of the overlap rate of the monitoring section A1 of 97.09, see Figure 2 As mentioned above, in terms of total amount, 97.09 is less than 95% of the total threshold of the warning standard. In terms of change, the predicted value change of 0.03 is less than 0.50 of the change threshold of the warning standard. Therefore, it can be concluded that the current displacement development of the section meets the requirements, and the next step is to continue monitoring according to the established plan.

[0056] In the above embodiment, the present invention discloses a method for controlling the impact of broken rock geological tunnel entrance construction on adjacent tunnel entrances, including setting monitoring sections, obtaining section monitoring results, analyzing section monitoring results and achieving control purposes. It has better safety and comprehensiveness and can be widely used in the field of tunnel construction.

[0057] The above description is a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings, characterized in that: The steps of the method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings are as follows: 1) Set monitoring section; The setting of monitoring sections includes setting n monitoring sections at a certain interval along the tunnel axis direction near the tunnel opening before the construction of the broken rock geological tunnel opening, which is represented by A i , i = 1 to n; 2) Obtain cross-section monitoring results; The cross-section monitoring results are obtained by, during the construction of the broken rock geological tunnel entrance, using three-dimensional laser scanning technology to scan each monitoring section A at a certain time interval. i The scanning results of m inner contour sections are obtained in sequence, and are sorted into a data set according to the acquisition time. i The obtained inner contour cross-section scanning results are expressed as the cross-section scanning result set C i = {P ij |j=1,2,...m}, where P ij is the j-th cross-sectional scanning result of the i-th section; 3) Analysis of cross-section monitoring results; The section monitoring results analysis includes the following: i The obtained inner contour cross-section scanning results are expressed as the cross-section scanning result set C i = {P ij |j=1,2,...m} for comparative analysis, the steps of comparative analysis are: a) Calculating the cross-sectional scanning result set C i The cross-sectional overlap rate of adjacent data B ik , the calculation formula is formula (1), In the formula, B ik For the set C i Medium i(k-1) With P i(k) The cross-sectional overlap ratio between the k-1,k P is the cross-sectional scanning result i(k-1) The cross-sectional scan results P i(k) The overlap area between them, S k-1 P is the cross-sectional scanning result i(k-1) The calculated value of the cross-sectional scanning area, b) After obtaining the calculation results according to formula (1), for section A i , sort out and obtain the monitoring section A i The cross-section coincidence rate series data set D i = {B ik |k=2,3,...m}; 4) Achievement of control objectives; The realization of the control purpose includes obtaining the monitoring section A i The cross-section coincidence rate series data set D i Analyze the data and obtain monitoring section A i The predicted value of the overlap rate B i(m+1) , and combined with the early warning standards, the monitoring section A i The stability of the system is evaluated and corresponding response measures are implemented according to the evaluation results to achieve the purpose of control.

2. The method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings according to claim 1 is characterized in that: In the above 2), the method for obtaining m inner contour line section scanning results for each monitoring section based on the three-dimensional laser scanning technology is as follows: for section A i , set the fixed tunnel section scanner position unchanged, and scan the current section A at a certain time interval i Perform inner contour line section scanning to obtain m inner contour line section scanning results.

3. The method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings according to claim 1 is characterized in that: In said 4), the monitoring section A is obtained i The predicted value of the overlap rate B i(m+1) The steps are: a) obtaining the monitoring section A i The cross-section coincidence rate series data set D i = {B ik |k=2,3,...m}, b) for the data section A i The data of the cross-section coincidence rate sequence data set are normalized, and c) the data cross section A is i The invention discloses a method for preparing a cross-sectional overlap rate sequence data set, comprising: dividing the data of the cross-sectional overlap rate sequence data set into a training set and a test set; d) constructing a long short-term memory neural network prediction model; f) using the training set to train the prediction model to obtain a trained prediction model; g) using the test set to test and adjust the trained prediction model to finally obtain a complete prediction model; and h) using the complete prediction model to predict the next data of the sequence data to obtain a prediction value Bi(m+1).

4. The method for controlling the impact of broken rock geological tunnel opening construction on adjacent tunnel openings according to claim 1 is characterized in that: The overlap area S k-1,k The acquisition method is as follows: a) for the cross-sectional scanning result P i(k-1) The cross-sectional scan results P i(k) , combined with the placement information of the instrument when obtaining the scanning results, draw the building boundary lines respectively, b) convert the cross-sectional scanning results P i(k-1) The cross-sectional scan results P i (k) Superimpose the building limit line and calculate the area of ​​the overlapping area, which is S k-1,k .

Images