Construction method for highway tunnel underpassing existing water-crossing tunnel

Abstract

The application discloses a kind of highway tunnel underpass existing water tunnel construction method, it is related to tunnel construction technical field, in the surface area of construction area, set up several collection points, obtain and generate rainfall coefficient Jxs, the construction area is divided into several monitoring areas, in monitoring area, randomly set up several first monitoring points, establish groundwater body dataset and generate groundwater body safety factor Dxs, according to groundwater body safety factor Dxs, corresponding monitoring area is determined as first-level alarm area;The position information of first-level alarm area is marked on electronic map, obtain the image information of rock stratum in each first-level alarm area, and the crack on rock stratum in first-level alarm area, if the crack quantity of rock stratum is greater than the preset quantity threshold, mark corresponding first-level alarm area and send out early warning. By establishing first-level alarm area and obtaining the crack on rock stratum surface, the safety state of rock stratum can be judged in time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel construction, in particular to a construction method for a highway tunnel underpassing an existing water-crossing tunnel. BACKGROUND

[0002] In the entire highway network in China, the proportion of tunnels is increasing, which inevitably leads to the situation of tunnel crossing each other. Due to the complex stress characteristics of tunnels and the complex changes of geology, the construction of a new tunnel underpassing an existing tunnel is always a difficult problem. Not only the safety of the new tunnel must be ensured when the new tunnel underpasses the existing tunnel at a close distance, especially when the new tunnel is excavated near the existing tunnel, but also the safety operation of the existing tunnel must be ensured as much as possible.

[0003] Therefore, how to make the new tunnel pass through the existing tunnel smoothly in the construction process and not affect the safe operation is a difficult problem. The excavation of the new tunnel can disturb the surrounding rock mass, and the disturbed surrounding rock mass will change the external force conditions due to deformation, which may cause the existing tunnel to settle, deform, even collapse, etc.

[0004] In the existing construction method of underpassing the existing tunnel, in order to fully ensure the safety of construction, determine the optimal construction method to ensure the safety of construction and reduce the influence on the operation of the existing tunnel, usually pay special attention to the rock stratum settlement in the construction process, so that corresponding protection measures can be taken according to the degree of rock stratum settlement.

[0005] However, due to the lack of early warning mechanism in the existing construction method, it is difficult to judge the safety state of the rock stratum in the construction area in time, and at the same time, due to the difficulty in obtaining the settlement value of the rock stratum at each position in advance during construction, it is necessary to take protective measures for the construction area before excavation and construction, which also reduces the efficiency of construction.

[0006] Therefore, the present application provides a construction method for a highway tunnel underpassing an existing water-crossing tunnel. SUMMARY

[0007] (I) Technical problems solved

[0008] In view of the deficiencies of the prior art, the present application provides a highway tunnel underpass existing water tunnel construction method, by setting a plurality of collection points in the surface area of the construction area, obtaining the rainfall coefficient Jxs, dividing the construction area into a plurality of monitoring areas, randomly setting a plurality of first monitoring points in the monitoring area, establishing the underground water body dataset and generating the underground water body safety coefficient Dxs, and determining the corresponding monitoring area as a first warning area according to the underground water body safety coefficient Dxs; marking the position information of the first warning area on the electronic map, obtaining the image information of the rock stratum in each first warning area, and the cracks on the rock stratum in the first warning area, if the number of cracks in the rock stratum is greater than the preset number threshold, marking the corresponding first warning area and issuing a warning outside. By establishing the first warning area and obtaining the cracks on the surface of the rock stratum, the safety state of the rock stratum can be judged in time, and timely warning can be ensured, so as to solve the problems in the background art.

[0009] (II) Technical scheme

[0010] To achieve the above object, the present application is implemented by the following technical scheme: a highway tunnel underpass existing water tunnel construction method, comprising the following steps: setting a plurality of collection points in the surface area of the construction area, monitoring and obtaining the surface humidity Bs of the surface soil layer and the soil water content Ts below the ground at each collection point; after collecting the surface humidity Bs and the soil water content Ts and performing dimensionless processing, the rainfall coefficient Jxs is generated according to the following formula:

[0011]

[0012] Wherein, C1 is a constant correction coefficient, F1 is a humidity factor, 0.64≤F1≤1.98, F2 is a water content factor, 1.13≤F2≤2.32; after obtaining the rainfall coefficient Jxs, if the rainfall coefficient Jxs is greater than the preset rainfall condition threshold, an electronic map of the construction area located underground is obtained, the construction area is divided into a plurality of monitoring areas in equal area, a plurality of first monitoring points are randomly set in the monitoring area, and the distance between two adjacent first monitoring points is not less than a preset distance threshold;

[0013] An underground water monitoring device is arranged at the first monitoring point, an underground water body dataset is established and an underground water body safety coefficient Dxs is generated, and when the underground water body safety coefficient Dxs is greater than a preset water body safety threshold, the corresponding monitoring area is marked; if the rainfall coefficient Jxs gradually decreases, but the underground water body safety coefficient Dxs in the marked area is still in an increasing state, the corresponding monitoring area is determined as a first warning area, and is displayed on the electronic map;

[0014] The position information of the first-level warning area is marked on the electronic map, and the trained path planning model plans a navigation path on the electronic map in combination with the position information, so that the inspection robot moves in the underground construction area; after imaging, the inspection robot obtains image information of the rock stratum in each first-level warning area, and obtains cracks on the rock stratum in the first-level warning area by image recognition on the image information; if the number of cracks in the rock stratum is greater than a preset number threshold, the corresponding first-level warning area is marked and a warning is sent outside.

[0015] Further, the underground water body safety coefficient Dxs is obtained in the following manner: the underground water level Dw of the first monitoring point is obtained first, if the underground water level Dw is greater than a preset water level threshold, the underground water pressure Ds and the underground water temperature Dt are obtained, and after the above data is summarized, an underground water body data set is established; after the underground water body data set is obtained, the underground water level Dw, the underground water pressure Ds and the underground water temperature Dt are dimensionless processed, and the underground water body safety coefficient Dxs is generated according to the following formula:

[0016]

[0017] Wherein, 0≤γ≤1, 0≤θ≤1, and 0.9≤γ+θ≤1.8, γ and θ are weights.

[0018] Further, a plurality of second monitoring points are arranged in the marked first-level warning area, and a rock stratum data collection device is arranged at the second monitoring points to periodically monitor the rock stratum structure information, obtain monitoring information and generate a rock stratum structure safety coefficient Yxs; if the rock stratum structure safety coefficient Yxs is greater than a preset structure safety threshold, the corresponding marked first-level warning area is upgraded to a second-level warning area and a warning is sent outside.

[0019] Further, the rock stratum structure safety coefficient Yxs is obtained in the following manner: the monitoring information includes a vibration speed Zp when the rock stratum vibrates, a rock stratum displacement Cy obtained when the vibration speed Zp exceeds a preset frequency threshold, and a rock stratum deformation variable Yb obtained when the rock stratum deforms; the vibration speed Zp, the rock stratum displacement Cy and the rock stratum deformation variable Yb are summarized to establish a rock stratum structure data set, and after the data in the rock stratum structure data set is dimensionless processed, the rock stratum structure safety coefficient Yxs is generated according to the following formula:

[0020]

[0021] Wherein, α and β are variable constant parameters, and the value range is as follows: 2.51≤α≤3.76, 3.61≤β≤7.93.

[0022] Further, if the number of secondary alert regions is greater than the preset alert threshold, a plurality of sets of groundwater body safety factors Dxs and a plurality of sets of rock stratum structure safety factors Yxs are respectively acquired at fixed time intervals; through Pearson correlation analysis, a correlation coefficient Rdy between the groundwater body safety factors Dxs and the rock stratum structure safety factors Yxs is acquired.

[0023] If the correlation coefficient Rdy is greater than a preset influence threshold, rock stratum structure data and groundwater body data are collected at the second monitoring point, and a model parameter data set is established after being summarized; after training and testing in combination with data in the model parameter data set, a tunnel rock stratum structure digital twin model is established.

[0024] Further, if the number of cracks in the rock stratum in the secondary alert region does not increase within a preset time, the tunnel rock stratum structure digital twin model is used in combination with a construction scheme to perform simulation analysis on the rock stratum settlement in the secondary alert region by taking the underpass excavation as an initial condition, to acquire a corresponding simulated settlement value Mcj; if the simulated settlement value Mcj is less than a predicted settlement value, the simulated settlement value Mcj must also be corrected.

[0025] Further, the correction method of the simulated settlement value Mcj is as follows: a corrected settlement value Xcj is generated according to the following formula:

[0026]

[0027] Wherein, n is the number of times of generating the simulated settlement value Mcj under different conditions of the rainfall coefficient Jxs, and F is a correction factor; the correction factor F is formed according to the following formula:

[0028]

[0029] Wherein, Dxs is the groundwater body safety factor, Yxs is the rock stratum structure safety factor, Rdy is the correlation coefficient between the groundwater body safety factor Dxs and the rock stratum structure safety factor Yxs, and C2 is a constant correction coefficient.

[0030] Further, a first settlement threshold and a second settlement threshold are preset, the first settlement threshold is greater than the second settlement threshold, and the corrected settlement value Xcj is acquired; if the corrected settlement value Xcj is less than the second settlement threshold, a first reinforcement strategy is adopted: primary lining, spraying concrete under the rock stratum, and setting a steel frame under the rock stratum to support the rock stratum.

[0031] Further, if the modified correction settlement value Xcj is between the first settlement threshold value and the second settlement threshold value, a second reinforcement strategy is adopted on the basis of the first reinforcement strategy: marking the hole position on the rock stratum, drilling a hole with a rock drill, and punching a guide pipe from the upper and middle parts of the steel frame with the rock drill, with the guide pipe end exposed and supported on the steel frame behind the excavation face to form a pre-supporting system with the steel frame, so as to support the rock stratum with the pre-supporting system.

[0032] Further, if the modified correction settlement value Xcj is higher than the first settlement threshold value: on the basis of the first and second reinforcement strategies, a third reinforcement strategy is adopted: increasing the thickness of the sprayed concrete on the rock stratum surface, and lengthening and densifying the anchor rods or increasing the diameter of the steel mesh and reducing the spacing, and performing secondary lining.

[0033] (Three) beneficial effects

[0034] The present application provides a highway tunnel underpass existing water tunnel construction method, has the following beneficial effects:

[0035] 1. The safety of the underground construction area is evaluated and judged by the underground water body safety factor Dxs value and its change, and the safety state of the rock stratum can be judged in time by establishing a first warning area and obtaining the cracks on the rock stratum surface, which is beneficial to timely early warning, thereby ensuring the safety of underground construction.

[0036] 2. By pre-setting the first settlement threshold value and the second settlement threshold value, the construction personnel can take protective measures in advance after obtaining the modified settlement value Xcj, so that the protective measures are more targeted, thereby fully ensuring the safety of underground construction and slowing down the actual possible rock stratum settlement.

[0037] 3. By sequentially forming a first warning area and a second warning area, the protection area is gradually reduced, and when construction is needed or protection is preferred, the area can be quickly determined to avoid comprehensive protection and reduce the amount of construction, and by establishing an early warning mechanism, the construction risk can be discovered and prevented in time; construction safety is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The present application provides a highway tunnel underpass existing water tunnel construction method, has the following beneficial effects: DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0040] Please refer to Figure 1 The present application provides a highway tunnel under the existing water tunnel construction method, comprising the following contents:

[0041] After the tunnel enters the construction phase, if the surface area of the construction area enters the continuous rainfall weather during construction, and the rainfall is large, the rainwater collects and seeps downward, which will have a certain influence on the underground rock mass conditions and groundwater conditions; At this time, on the basis of obtaining the tunnel construction scheme: a plurality of collection points are set on the surface area of the construction area, and the surface humidity Bs of the surface soil layer and the soil water content Ts one meter below the ground are monitored and obtained at each collection point; After the surface humidity Bs and the soil water content Ts are collected and dimensionless processed, the rainfall coefficient Jxs is generated according to the following formula:

[0042]

[0043] Wherein, C1 is a constant correction coefficient, F1 is a humidity factor, 0.64≤F1≤1.98, F2 is a water content factor, 1.13≤F2≤2.32; The rainfall coefficient Jxs is used to preliminarily evaluate the external environmental conditions of the construction area. If the external environmental conditions are good, the construction will proceed normally. If the external weather conditions are poor and may have a certain negative impact on the underground construction area, the construction environment needs to be improved in time, or the construction will continue after the weather improves.

[0044] After obtaining the rainfall coefficient Jxs, if the rainfall coefficient Jxs is greater than the preset rainfall condition threshold, after obtaining the electronic map of the underground construction area, the construction area is divided into a plurality of monitoring areas in equal area, a plurality of first monitoring points are randomly set in the monitoring area, and the distance between two adjacent first monitoring points is not less than a preset distance threshold, so as to prevent the monitoring data of different monitoring points from being too similar.

[0045] The underground water monitoring device, such as pressure gauge, temperature sensor, etc., is set at the first monitoring point to obtain the underground water level Dw of the first monitoring point. If the underground water level Dw is greater than the preset water level threshold, the water pressure Ds and the underground water temperature Dt of the underground water are continuously obtained. After the above data is collected, the underground water body dataset is established; wherein, the underground water environment is periodically monitored, the period is half an hour or one hour, which can be freely set and is not limited further.

[0046] After obtaining the underground water body dataset, the underground water level Dw, water pressure Ds and underground water temperature Dt are dimensionless processed, and the underground water body safety coefficient Dxs is generated according to the following formula:

[0047]

[0048] Wherein, 0≤γ≤1, 0≤θ≤1, and 0.9≤γ+θ≤1.8, γ, θ are weights, and the specific values thereof are adjusted and set by a user;

[0049] In use, the generated groundwater body safety factor Dxs can preliminarily judge whether the underground construction area is safe, and when the groundwater body safety factor Dxs is greater than the preset water body safety threshold, the corresponding monitoring area is marked;

[0050] If the rainfall coefficient Jxs gradually decreases, but the groundwater body safety factor Dxs in the marked area is still in an increasing state, it indicates that the groundwater state of the monitoring area is gradually deteriorating under the influence of continuous rainfall, and the groundwater of other areas is also converging or seeping to the monitoring area, which will eventually have a great impact on the rock stratum of the construction area and cause safety hazards. Under this condition, sufficient drainage or other safety management measures need to be taken, and the load on the rock stratum above also needs to be reduced and the erosion of the rock stratum by groundwater needs to be reduced.

[0051] At this time, the corresponding monitoring area is determined as a first warning area, and the position information of the first warning area is marked on the electronic map. The trained path planning model plans a navigation path on the electronic map in combination with the position information, so that the inspection robot moves in the underground construction area.

[0052] The position information of the first warning area is marked on the electronic map, and the trained path planning model plans a navigation path on the electronic map in combination with the position information, so that the inspection robot moves in the underground construction area.

[0053] After imaging, the inspection robot acquires image information of the rock stratum in each first warning area, and obtains cracks on the rock stratum in the first warning area by image recognition on the image information. If the number of cracks on the rock stratum is greater than a preset number threshold, the corresponding first warning area is marked and a warning is issued.

[0054] In use, the underground water environment in the construction area is monitored when it is in a state of continuous rainfall outside the construction area, and the groundwater body safety factor Dxs is established and acquired based on the monitoring data. Through the change of the value of the groundwater body safety factor Dxs, the safety of the underground construction area can be evaluated and judged, and through the establishment of the first warning area and the acquisition of the cracks on the rock stratum surface, the safety state of the rock stratum can be judged in time, which is beneficial to timely warning and thus ensures the safety of underground construction.

[0055] Reference Figure 1 A plurality of second monitoring points are arranged in the marked first warning area, and rock stratum data acquisition devices such as deformation monitoring instruments, vibration sensors and displacement sensors are arranged at the second monitoring points to periodically monitor the rock stratum structure information,

[0056] The monitoring information includes a vibration speed Zp when the rock stratum produces vibration, a displacement of the rock stratum when the vibration speed Zp exceeds a preset frequency threshold, a displacement Cy of the rock stratum, and a deformation amount Yb of the rock stratum when the rock stratum produces deformation.

[0057] The vibration speed Zp, the displacement Cy of the rock stratum, and the deformation amount Yb are summarized to establish a rock stratum structure data set, and after the data in the rock stratum structure data set is processed dimensionlessly, a rock stratum structure safety coefficient Yxs is generated according to the following formula:

[0058]

[0059] wherein a and β are variable constant parameters, and the value ranges are as follows: 2.51≤a≤3.76 and 3.61≤β≤7.93, and a user can adjust them according to actual conditions;

[0060] If the rock stratum structure safety coefficient Yxs is greater than a preset structure safety threshold, the corresponding marked first warning area is upgraded to a second warning area and a warning is sent outward.

[0061] In use, the rock stratum structure safety coefficient Yxs is continuously generated on the basis of the first warning area, and the safety of the rock stratum is judged by the rock stratum structure safety coefficient Yxs, which is more comprehensive than image recognition alone, and when the rock stratum structure safety coefficient Yxs value is abnormal, it is also convenient for construction personnel to judge whether to carry out the next operation.

[0062] Reference Figure 1 If the number of second warning areas is greater than a preset warning threshold, a plurality of sets of underground water body safety coefficients Dxs and a plurality of sets of rock stratum structure safety coefficients Yxs are respectively acquired at fixed time intervals; through Pearson correlation analysis, a correlation coefficient Rdy between the underground water body safety coefficient Dxs and the rock stratum structure safety coefficient Yxs is acquired.

[0063] If the correlation coefficient Rdy is greater than a preset influence threshold, rock stratum structure data such as rock stratum structure, porosity, permeability, and strength, and underground water body data such as flow rate, flow velocity, water level, water body pressure, and water body temperature of the underground water body are collected at the second monitoring point; after the above monitoring data are summarized to establish a model parameter data set, a tunnel rock stratum structure digital twin model is established by combining the data in the model parameter data set after training and testing.

[0064] In use, when the number of second warning areas is greater than a preset warning threshold and the correlation coefficient Rdy is greater than a preset influence threshold, the tunnel rock stratum structure digital twin model is established, and after the initial conditions are determined on the basis of the tunnel rock stratum structure digital twin model, the safety of the rock stratum can be simulated and analyzed.

[0065] If the number of cracks in the rock stratum in the secondary alert area does not increase within the preset time, the tunnel rock stratum structure digital twin model is used in combination with the construction scheme to simulate and analyze the rock stratum settlement in the secondary alert area as an initial condition of the underpass excavation, and the corresponding simulated settlement value Mcj is obtained. In use, when it is inconvenient to obtain the actual rock stratum settlement result under the construction state, the actual rock stratum settlement value is replaced by the simulation analysis result through simulation analysis, thereby reducing the cost and monitoring time of actual monitoring.

[0066] However, considering that the simulated settlement value Mcj generated by simulation simulation is usually higher than the actual settlement value due to errors and deficiencies in parameter selection, algorithm selection and training, if the simulated settlement value Mcj is less than the estimated settlement value, the simulated settlement value Mcj must also be corrected. Therefore, the corrected settlement value Xcj is generated according to the following formula:

[0067]

[0068] where n is the number of times the simulated settlement value Mcj is generated under different conditions of the rainfall coefficient Jxs, F is the correction factor, and the correction factor F is formed in accordance with the following formula:

[0069]

[0070] where Dxs is the underground water body safety coefficient, Yxs is the rock stratum structure safety coefficient, Rdy is the correlation coefficient between the underground water body safety coefficient Dxs and the rock stratum structure safety coefficient Yxs, and C2 is a constant correction coefficient.

[0071] In use, the simulated settlement value Mcj is corrected by the correction factor F in a dimensionless state to generate the corrected settlement value Xcj, which may be closer to the actual rock stratum settlement. Construction personnel can take corresponding safety measures when the rock stratum may settle according to the corrected settlement value Xcj.

[0072] Reference Figure 1 The first and second settlement thresholds are set in advance, the first settlement threshold is greater than the second settlement threshold, and the corrected settlement value Xcj is obtained.

[0073] If the corrected corrected settlement value Xcj is less than the second settlement threshold, the first reinforcement strategy is adopted: initial lining, spraying concrete under the rock stratum, and setting a steel frame under the rock stratum to support the rock stratum.

[0074] If the modified correction subsidence value Xcj is between the first subsidence threshold value and the second subsidence threshold value, a second reinforcement strategy is adopted on the basis of the first reinforcement strategy: marking the hole position on the rock stratum, drilling a hole with a rock drill, and punching a guide pipe from the upper and middle parts of the steel frame with the rock drill, the guide pipe being exposed at the end and supported on the steel frame behind the excavation face to form a pre-supporting system with the steel frame to support the rock stratum; the guide pipe is a steel pipe with a diameter of 108 mm, a steel cage is embedded in the pipe, and a grouting pump is used to press the cement slurry into the guide pipe until the grouting pressure of each hole reaches 1.0 MPa and the grouting amount reaches more than 95% of the designed amount.

[0075] If the modified correction subsidence value Xcj is higher than the first subsidence threshold value: on the basis of the first and second reinforcement strategies, a third reinforcement strategy is adopted: increasing the thickness of the sprayed concrete on the rock stratum surface, and lengthening and densifying the anchor rods or increasing the diameter of the steel mesh and reducing the spacing, and constructing a secondary lining.

[0076] In use, by pre-setting the first subsidence threshold value and the second subsidence threshold value, after obtaining the modified correction subsidence value Xcj, the construction personnel can take protective measures in advance, so that the protective measures are more targeted, and the safety of underground construction is fully guaranteed, and the rock stratum subsidence is slowed down;

[0077] At the same time, by sequentially forming the first warning area and the second warning area, the protection area is gradually reduced, when construction is needed or protection is given priority, the area can be quickly determined, full protection is avoided, the amount of construction is reduced, and through the establishment of the early warning mechanism, when there is a construction risk, it can be discovered and prevented in time, and the construction safety is guaranteed.

[0078] The above embodiments can be realized wholly or partially by software, hardware, firmware or any combination thereof. When realized by software, the above embodiments can be realized in the form of a computer program product wholly or partially. Those skilled in the art can realize that the units and algorithm steps of the examples described in connection with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solutions.

[0079] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e. they can be located in one place or distributed on multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiments according to actual needs.

[0080] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A construction method for a highway tunnel to underpass an existing water-crossing tunnel, characterized in that: Comprise the following steps: A plurality of collection points are arranged in the ground surface area of the construction area, and the surface humidity Bs of the ground soil layer and the soil water content Ts below the ground are monitored and obtained at each collection point; after the surface humidity Bs and the soil water content Ts are collected and dimensionless processed, the rainfall coefficient Jxs is generated according to the following formula: Wherein, C1 is a constant correction coefficient, F1 is a humidity factor, 0.64≤F1≤1.98, F2 is a water content factor, 1.13≤F2≤2.32; After obtaining the rainfall coefficient Jxs, if the rainfall coefficient Jxs is greater than a preset rainfall condition threshold, an electronic map of the underground construction area is obtained, the construction area is divided into a plurality of monitoring areas in equal area, a plurality of first monitoring points are randomly arranged in the monitoring areas, and the distance between adjacent two first monitoring points is not less than a preset distance threshold; An underground water monitoring device is arranged at the first monitoring point, an underground water body data set is established, and an underground water body safety coefficient Dxs is generated; when the underground water body safety coefficient Dxs is greater than a preset water body safety threshold, the corresponding monitoring area is marked; if the rainfall coefficient Jxs gradually decreases, but the underground water body safety coefficient Dxs in the marked area is still in an increasing state, the corresponding monitoring area is determined as a first warning area, and the first warning area is displayed on the electronic map; The position information of the first warning area is marked on the electronic map, the trained path planning model plans a navigation path on the electronic map in combination with the position information, so that the inspection robot moves in the underground construction area; after imaging, the inspection robot obtains image information of the rock stratum in each first warning area, obtains cracks on the rock stratum in the first warning area by image recognition on the image information, and if the number of cracks on the rock stratum is greater than a preset number threshold, the corresponding first warning area is marked and a warning is issued.

2. The construction method of a highway tunnel underpassing an existing water-crossing tunnel according to claim 1, characterized in that: The underground water body safety coefficient Dxs is obtained as follows: The underground water level Dw of the first monitoring point is obtained preferentially, if the underground water level Dw is greater than a preset water level threshold, the water pressure Ds and the underground water temperature Dt of the underground water are obtained, and after the above data is collected, an underground water body data set is established; After obtaining the underground water body data set, the underground water level Dw, the water pressure Ds and the underground water temperature Dt are dimensionless processed, and the underground water body safety coefficient Dxs is generated according to the following formula: Wherein, 0≤γ≤1, 0≤θ≤1, and 0.9≤γ+θ≤1.8, γ and θ are weights.

3. The construction method of a highway tunnel underpassing an existing water-crossing tunnel according to claim 2, characterized in that: A plurality of second monitoring points are arranged in the marked first warning area, a rock stratum data acquisition device is arranged at the second monitoring point, the rock stratum structure information is periodically monitored, the monitoring information is obtained, and a rock stratum structure safety coefficient Yxs is generated; If the rock stratum structure safety coefficient Yxs is greater than a preset structure safety threshold, the corresponding marked first warning area is upgraded to a second warning area and a warning is issued.

4. The construction method of a highway tunnel underpassing an existing water-crossing tunnel according to claim 3, characterized in that: The rock stratum structure safety coefficient Yxs is obtained as follows: The monitoring information includes: vibration velocity Zp when the rock stratum produces vibration, displacement of the rock stratum when the vibration velocity Zp exceeds a preset frequency threshold, rock stratum displacement Cy, and deformation amount of the rock stratum when the rock stratum produces deformation, and rock stratum deformation amount Yb; the vibration velocity Zp, the rock stratum displacement Cy, and the rock stratum deformation amount Yb are summarized to establish a rock stratum structure data set, and after dimensionless processing is performed on data in the rock stratum structure data set, a rock stratum structure safety coefficient Yxs is generated according to the following formula: Wherein, α and β are variable constant parameters, and the value range is as follows: 2.51≤α≤3.76, 3.61≤β≤7.

93.

5. The construction method of a highway tunnel underpassing an existing water-crossing tunnel according to claim 4, characterized in that: If the number of the secondary warning areas is greater than a preset warning threshold, a plurality of sets of the underground water body safety coefficient Dxs and a plurality of sets of the rock stratum structure safety coefficient Yxs are respectively acquired at fixed time intervals; Through Pearson correlation analysis, a correlation coefficient Rdy between the underground water body safety coefficient Dxs and the rock stratum structure safety coefficient Yxs is acquired; If the correlation coefficient Rdy is greater than a preset influence threshold, rock stratum structure data and underground water body data are collected at the second monitoring point, and a model parameter data set is established after summarization; After training and testing in combination with data in the model parameter data set, a tunnel rock stratum structure digital twin model is established.

6. The construction method of a highway tunnel underpassing an existing water-crossing tunnel according to claim 5, characterized in that: If the number of cracks of the rock stratum in the secondary warning area does not increase within a preset time, the tunnel rock stratum structure digital twin model is used in combination with a construction scheme to perform simulation analysis on rock stratum settlement in the secondary warning area as an initial condition to obtain a corresponding simulated settlement value Mcj; if the simulated settlement value Mcj is less than a predicted settlement value, the simulated settlement value Mcj must also be corrected.

7. The construction method of a highway tunnel underpassing an existing water-crossing tunnel according to claim 6, characterized in that: The correction method of the simulated settlement value Mcj is as follows: a corrected settlement value Xcj is generated according to the following formula: Wherein, n is the number of times of generating the simulated settlement value Mcj under different conditions of the rainfall coefficient Jxs, and F is a correction factor; the correction factor F is formed according to the following formula: Wherein, Dxs is the underground water body safety coefficient, Yxs is the rock stratum structure safety coefficient, Rdy is the correlation coefficient between the underground water body safety coefficient Dxs and the rock stratum structure safety coefficient Yxs, and C2 is a constant correction coefficient.

8. The construction method of a highway tunnel underpassing an existing water-crossing tunnel according to claim 7, characterized in that: A first settlement threshold and a second settlement threshold are preset, the first settlement threshold is greater than the second settlement threshold, and the corrected settlement value Xcj is acquired; if the corrected settlement value Xcj after correction is less than the second settlement threshold, a first reinforcement strategy is adopted: initial lining, spraying concrete under the rock stratum, and setting a steel frame under the rock stratum to form support for the rock stratum.

9. The construction method of a highway tunnel underpassing an existing water-crossing tunnel according to claim 8, characterized in that: If the corrected settlement value Xcj after correction is between the first settlement threshold and the second settlement threshold, a second reinforcement strategy is adopted on the basis of the first reinforcement strategy: designing hole positions on the rock stratum and marking, drilling holes by a rock drill, and drilling a guide pipe into the upper and middle parts of the steel frame by the rock drill, so that the guide pipe is exposed at the end and supported on the steel frame behind the excavation face to form a pre-supporting system with the steel frame, thereby forming support for the rock stratum by the pre-supporting system.

10. The construction method of a highway tunnel underpassing an existing water-crossing tunnel according to claim 9, characterized in that: If the corrected settlement value Xcj after correction is higher than the first settlement threshold: on the basis of the first and second reinforcement strategies, a third reinforcement strategy is adopted: Three reinforcement strategies: increase the thickness of the concrete surface, and lengthen the encryption anchor rod or increase the diameter of the reinforcement mesh and reduce the spacing, The second lining is applied.

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