Visualization method for rockburst assessment of deep and long tunnels based on BIM model

Abstract

The present invention relates to the technical field of tunnel survey and construction, and in particular to a visualization method for rockburst assessment of deep-buried long tunnels based on a BIM model. A BIM model having a three-dimensional geological model of a tunnel site and a tunnel model is established, and the BIM model is subjected to geostress inversion to obtain the three-dimensional geostress distribution of the tunnel site, which is input into the BIM model, and the high geostress area is divided. The BIM model is divided into potential rockburst sections and rockburst grade assessment is performed according to preset length segments, and the graphic element information of the BIM model in the segment is changed according to the assessment result, and a visualization expression is performed. Finally, the BIM model is subjected to tunnel excavation numerical simulation, and combined with finite element numerical analysis, suggestions are made on the excavation method. The present invention realizes the storage of tunnel data and rockburst assessment information, and also realizes the visualization expression of rockburst assessment results.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel exploration and construction, and particularly relates to a visualization method for rockburst assessment of deep-buried long tunnels based on a BIM model. Background Art

[0002] Tunnels can be divided into two categories: deep-buried tunnels and shallow-buried tunnels according to the burial depth. Most of the tunnels along the major railway projects in the southwestern region of China are long tunnels with a length of dozens of kilometers. For such deep-buried long tunnels passing through hard rock development areas, high-stress rockburst disasters seriously threaten the construction safety. Therefore, it is particularly important to carry out rockburst assessment in the high-stress areas of deep-buried long tunnels during the exploration and design stage. The rockburst assessment results will effectively affect the adjustment of the engineering line and the optimization of the construction plan.

[0003] For deep-buried long tunnels, it is relatively common to carry out rockburst assessment work with a section length of 100 meters. However, in existing actual projects, high-stress rockburst phenomena also occur in some shallow-buried sections of deep-buried long tunnels due to the influence of the stress distribution characteristics of high mountains and river valleys. Since the existing technology uses a section length of 100 meters (including 100 meters and several hundred meters) for section division, this means that only one rockburst assessment result is output for the 100-meter section length area, ignoring the possible details at each location within the 100-meter section length and being unable to intuitively know the rockburst assessment situation within this section. Therefore, this type of shallow-buried rockburst in the river valley stress field is often ignored in the rockburst assessment work carried out in 100-meter sections. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems in the prior art that due to only one rockburst assessment result being output for the 100-meter section length area, some shallow-buried sections of deep-buried long tunnels are easily ignored in the rockburst assessment and the rockburst assessment situation is not intuitive, and to provide a visualization method for rockburst assessment of deep-buried long tunnels based on a BIM model.

[0005] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] A visualization method for rockburst assessment of deep-buried long tunnels based on a BIM model, comprising the following steps:

[0007] S1, establish a BIM model with a three-dimensional geological model of the tunnel site area; based on the three-dimensional geological model of the tunnel site area in the BIM model, establish a tunnel model segmented by a preset length; the preset length segment is less than 100 meters;

[0008] S2, import the BIM model into a three-dimensional finite difference program for mesh generation, obtain the simulation parameters of geotechnical physical parameters, perform in-situ stress inversion on the BIM model, and obtain the three-dimensional in-situ stress distribution of the tunnel site area;

[0009] S3. Input the in-situ stress distribution into the BIM model, and divide the high in-situ stress area of the BIM model according to a threshold value.

[0010] S4. Divide the potential rockburst sections of the BIM model and evaluate the rockburst grades by segmenting according to the preset length, and change the element information of the BIM model in the potential rockburst sections according to the results of the division of the potential rockburst sections and / or the evaluation of the rockburst grades.

[0011] Further, after step S4 is executed, the method further includes the following steps:

[0012] S5. Conduct numerical simulation of tunnel excavation on the BIM model, and combine finite element numerical analysis to provide suggestions for the excavation method.

[0013] Further, in step S1, establishing a BIM model with a 3D geological model of the tunnel site area specifically includes: establishing a BIM model with a 3D geological model of the tunnel site area according to the lithology, surrounding rock category, and geological structure in the geological exploration data of the tunnel area to be evaluated; in step S1, the tunnel model includes geological characteristics and tunnel design parameter information such as tunnel site lithology information, surrounding rock grade information, rock mass mechanics information, contour elevation information, buried depth information along the tunnel, and tunnel dimension information.

[0014] Further, step S3 specifically includes:

[0015] S31. Calculate the average in-situ stress in each preset length segment of the tunnel model according to the in-situ stress distribution, and input it into the BIM model.

[0016] S32. Divide the high in-situ stress area of the BIM model according to a threshold value.

[0017] Further, when dividing the potential rockburst sections of the BIM model and evaluating the rockburst grades by segmenting according to the preset length in step S4, if the BIM model in the preset length segment is a high stress area, then in the preset length segment, divide the potential rockburst sections of the BIM model and evaluate the rockburst grades by segmenting according to a second preset length; where the second preset length is less than the preset length.

[0018] Further, the methods for dividing the rockburst sections and evaluating the rockburst grades in step S4 specifically include:

[0019] Division of rockburst sections: Divide the rockburst sections based on the high in-situ stress area, surrounding rock category, buried depth information along the tunnel, surrounding rock grade information, and rock mass mechanics information.

[0020] Rockburst level assessment: The rock strength-stress ratio method or the rock stress-strength ratio method is selected for rockburst level assessment, and the rockburst level assessment includes five categories: no rockburst, slight rockburst, moderate rockburst, strong rockburst, and extremely strong rockburst.

[0021] Furthermore, the method of changing the element information of the BIM model within the potential rockburst section according to the potential rockburst section division and / or rockburst level assessment result in step S4 specifically includes:

[0022] In the BIM model, the rockburst level assessment results from no rockburst to extremely strong rockburst are presented in a color gradient manner.

[0023] Furthermore, the three-dimensional finite difference program in step S2 is the FLAC3D software.

[0024] Furthermore, step S2 specifically includes the following steps:

[0025] Import the three-dimensional geological BIM model of the tunnel site area into the FLAC3D software for mesh division and mesh refinement;

[0026] Obtain the simulation parameters of the geotechnical physical parameters through indoor tests and the recommended values of geotechnical physical parameters in the geological exploration report;

[0027] In the FLAC3D software, fix the lower, left, right, front, and back 5 faces of the BIM model, and consider the self-weight of the overlying rock mass layer of the tunnel;

[0028] Adopt the Mohr-Coulomb elastoplastic constitutive model for in-situ stress inversion to obtain the calculated value of the in-situ stress distribution in the tunnel site area;

[0029] Based on the calculated value of the in-situ stress distribution in the tunnel site area and combined with the measured data of in-situ stress by the deep-hole hydraulic fracturing method in the project, obtain the three-dimensional in-situ stress distribution in the tunnel site area.

[0030] Furthermore, the simulation parameters of the geotechnical physical parameters include elastic modulus, Poisson's ratio, shear modulus, residual strength, cohesion, and internal friction angle.

[0031] Compared with the prior art, the beneficial effects of the present invention:

[0032] The present invention provides a solution for the refined evaluation of rockburst and the visualization of results based on BIM technology. By establishing a BIM model with a three-dimensional geological model and a tunnel model of the tunnel site area, performing in-situ stress inversion on the BIM model to obtain the three-dimensional in-situ stress distribution of the tunnel site area, inputting it into the BIM model, dividing the high in-situ stress area, segmenting the BIM model according to a preset length to divide potential rockburst sections and evaluate rockburst grades, changing the primitive information of the BIM model within the segment according to the evaluation results for visual expression, and finally conducting numerical simulation of tunnel excavation on the BIM model, and combining finite element numerical analysis to provide suggestions on the excavation method. The present invention digitally stores rockburst evaluation work and parameter information using BIM technology, achieving effective storage of data on the geology of the tunnel site area, data on long deep-buried tunnels, and rockburst evaluation information; by segmenting the BIM model including the three-dimensional geological model and the tunnel model of the tunnel site area according to a preset length of less than 100 meters for rockburst evaluation respectively, achieving refined evaluation of long deep-buried tunnels, and also realizing a more intuitive visual expression of the rockburst evaluation results by changing the primitives of the BIM model. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flowchart of the visualization method for rockburst evaluation of long deep-buried tunnels based on BIM model in Embodiment 1.

[0034] Figure 2 It is a schematic diagram of the three-dimensional geological model of the tunnel site area in Embodiment 1.

[0035] Figure 3 It is a schematic diagram of the three-dimensional in-situ stress distribution of the tunnel site area in Embodiment 1.

[0036] Figure 4 It is a schematic diagram of the division of high in-situ stress sections in Embodiment 1.

[0037] Figure 5 It is a schematic diagram of the division of rockburst sections in Embodiment 1.

[0038] Figure 6 It is a schematic diagram of the division of sections to be evaluated for rockburst and the rockburst evaluation results in Embodiment 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The present invention will be further described in detail below in combination with test examples and specific embodiments. However, it should not be understood that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments. All technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0040] Since the BIM model itself has the characteristics of fine geometric structure and covering parameter feature information, and can realize the function of three-dimensional digital visualization expression of traditional engineering two-dimensional graphics, the present invention provides a solution for the refined evaluation of rockburst and the visualization of results based on BIM technology.

[0041] The rockburst assessment and visualization method described in the present invention is mainly carried out in deep-buried tunnels, which is beneficial to solving the problem that the shallow-buried area of deep-buried tunnels is easily overlooked when the evaluation section is divided into hundreds of meters. Therefore, it is necessary to distinguish between the shallow-buried area of deep-buried tunnels and shallow-buried tunnels. The division of deep-buried tunnels and shallow-buried tunnels is defined by the maximum burial depth of an entire tunnel. For example, if the maximum burial depth of a tunnel is 2000m, this tunnel is a deep-buried tunnel, but there is also a section in this tunnel with a burial depth of 500m, which is the shallow-buried area of the deep-buried tunnel; the shallow-buried area is a relative concept relative to the maximum burial depth of the tunnel. The deep-buried area in a shallow-buried tunnel will not exceed a maximum burial depth of 500m. For example, a tunnel with a maximum burial depth of 500m is a shallow-buried tunnel.

[0042] Embodiment 1

[0043] A visualization method for rockburst assessment of long deep-buried tunnels based on a BIM model, as Figure 1 shown, includes the following steps:

[0044] S1. Establish a BIM model with a three-dimensional geological model of the tunnel site area; based on the three-dimensional geological model of the tunnel site area in the BIM model, establish a tunnel model segmented by a preset length; the preset length segment is less than 100 meters;

[0045] S2. Import the BIM model into a three-dimensional finite difference program for mesh generation, obtain the simulation parameters of geotechnical physical parameters, perform in-situ stress inversion on the BIM model, and obtain the three-dimensional in-situ stress distribution of the tunnel site area;

[0046] S3. Input the in-situ stress distribution into the BIM model, and divide the high in-situ stress area of the BIM model according to a threshold;

[0047] S4. Divide the potential rockburst sections of the BIM model and evaluate the rockburst grades according to the preset length segments, and change the primitive information of the BIM model in the potential rockburst sections according to the results of the potential rockburst section division and / or rockburst grade evaluation;

[0048] S5. Carry out numerical simulation of tunnel excavation on the BIM model, and combine finite element numerical analysis to give suggestions on the excavation method.

[0049] In step S1, to establish a BIM model with a three-dimensional geological model of the tunnel site area, it specifically includes: according to the geological exploration data of the long deep-buried tunnel area to be evaluated, distinguish lithology, surrounding rock categories, geological structures, etc. to establish a BIM model with a three-dimensional geological model of the tunnel site area covering digital information. The schematic diagram of the three-dimensional geological model of the tunnel site area is as Figure 2As shown in the figure. A tunnel model is established based on the three-dimensional geological model of the tunnel site area in the BIM model, specifically including: on the basis of the three-dimensional geological model of the tunnel site area, a tunnel model segmented by a preset length is established; wherein, the tunnel model includes geological features such as tunnel site lithology information, surrounding rock grade information, rock mass mechanics information, contour elevation information, buried depth information along the tunnel, and tunnel dimension information, as well as tunnel design parameter information. Since both the three-dimensional geological model of the tunnel site area and the tunnel model are in the same BIM model, the BIM model also has the above information. In the present invention, the smaller the value of the preset length segmentation, the smaller the evaluation section and the more accurate the evaluation, but the larger the amount of data to be processed; preferably, the present invention proposes that the preset length segmentation is carried out in segments of 50 meters. When the preset length segmentation is 50 meters, it is possible to narrow the rockburst evaluation interval and better achieve the balance between the fine evaluation and control requirements of deep-buried long tunnels (such as deep-buried long tunnels of 30,000 meters) and the amount of data to be processed.

[0050] The three-dimensional finite difference program described in step S2 is the FLAC3D software. Specifically, step S2 specifically includes the following steps:

[0051] Import the three-dimensional geological BIM model of the tunnel site area into the FLAC3D software for mesh generation, and locally encrypt the mesh for complex geological areas. The complex geological areas are fault fracture zones, lithology dividing lines, structural plane influence areas, etc., and group the complex geological areas and arrange multiple measuring points in the model;

[0052] Obtain the simulation parameters of the geotechnical physical parameters through indoor tests and the recommended values of geotechnical physical parameters in the geological exploration report, including elastic modulus, Poisson's ratio, shear modulus, residual strength, cohesion, internal friction angle, etc.;

[0053] In the FLAC3D software, fix the lower, left, right, front, and rear 5 faces of the BIM model and consider the self-weight of the overlying rock mass layer of the tunnel;

[0054] Adopt the Mohr-Coulomb elastoplastic constitutive model for in-situ stress inversion to obtain the calculated value of the in-situ stress distribution in the tunnel site area;

[0055] Based on the calculated value of the in-situ stress distribution in the tunnel site area, combined with the measured data of in-situ stress by the engineering deep-hole hydraulic fracturing method, obtain the three-dimensional in-situ stress distribution in the tunnel site area.

[0056] The schematic diagram of the three-dimensional in-situ stress distribution in the tunnel site area is as Figure 3 shown. The color change from green to blue indicates that the in-situ stress decreases from large to small.

[0057] In step S3, it specifically includes:

[0058] S31. Calculate the average in-situ stress of each preset length segment of the tunnel model according to the in-situ stress distribution obtained in step S2. That is, in this embodiment, calculate the average in-situ stress within each 50-meter segment and input it into the BIM model for digital expression and storage.

[0059] S32. Divide the high in-situ stress area of the BIM model according to a threshold. In this embodiment, combined with the in-situ stress distribution characteristics of the tunnel site area, select an appropriate high / low in-situ stress boundary threshold of 20 MPa to divide the high in-situ stress sections along the tunnel.

[0060] The schematic diagram of the high in-situ stress section division is as Figure 4 shown.

[0061] In step S4, when dividing the potential rockburst sections and evaluating the rockburst grades of the BIM model according to the preset length segments, if the BIM model in the preset length segment is a high stress area, then within the preset length segment, divide the potential rockburst sections and evaluate the rockburst grades of the BIM model according to the second preset length segment; where the second preset length segment is less than the preset length segment. In another possible implementation, for sections with relatively shallow burial depth but high stress, appropriately densify the evaluation section length, that is, reduce the section length and increase the number of sections to improve the evaluation accuracy.

[0062] In step S4, the methods for dividing the rockburst sections and evaluating the rockburst grades specifically include:

[0063] Rockburst section division: Based on the high in-situ stress area division results in step S32, further refine the control factors that may affect the rockburst grade, such as the surrounding rock type, surrounding rock grade information, tunnel burial depth information along the line (which can be in 100m steps), and rock mass mechanical parameters, within each high in-situ stress section to form potential rockburst sections to be evaluated. For example, when a certain 50-meter section is designated as a high stress area according to the method in step S32, in order to further carry out refined evaluation work on this section, it is necessary to further divide the potential rockburst sections. According to the analysis of the actual geological situation, there are two lithologies, granite and marble, two grades of surrounding rock, II and III, and three rock mass mechanical parameters (II-class granite, III-class granite, II-class marble) within this section, and the burial depth range of this section is 700 - 750m. Therefore, further divide this 50m high stress section into three potential rockburst sections (0 - 12m section, 12 - 35m section, and 35 - 50m section) as shown in Figure 5 shown.

[0064] Rockburst level assessment: In the potential rockburst sections to be evaluated, the rock strength-stress ratio method or the rock stress-strength ratio method, or other commonly used rockburst criteria in engineering are selected for rockburst level assessment. The rockburst level assessment includes five categories: no rockburst, slight rockburst, moderate rockburst, strong rockburst, and extremely strong rockburst.

[0065] In step S4, in a possible implementation manner, the method for changing the element information of the BIM model in the potential rockburst section according to the division of the potential rockburst section and / or the rockburst level assessment result specifically includes:

[0066] Select different colors and display the five rockburst level assessment results from no rockburst to extremely strong rockburst in the BIM model from light to deep.

[0067] The schematic diagram of the division of the rockburst section to be evaluated and the rockburst assessment result is as Figure 6 shown.

[0068] In step S5, in a possible implementation manner, the BIM model containing the 3D geological model of the tunnel site area and the tunnel model is imported into the ANSYS platform, and the bench cut method excavation numerical simulation under different working conditions is carried out for the potential rockburst sections in S04. Combining the finite element numerical analysis results, rockburst prevention and control suggestions for the high-risk rockburst areas are put forward from the perspectives of excavation methods and working conditions.

[0069] In step S5, reference can be made to the research report "Research on the Rockburst Incubation Process" (Feng Xiating, 2019). By using technical means such as indoor rock sample tests, indoor physical model tests, numerical simulations, on-site comprehensive observations, and on-site monitoring of the rockburst incubation process, according to the mechanisms of different types of rockburst incubation processes and the microseismic evolution laws of different types of rockbursts induced by different construction methods, and using the above-mentioned rockburst assessment method and the quantitative assessment method of rockburst areas and levels, dynamic prevention and control technologies for different types of rockbursts induced by different construction methods are given.

[0070] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A visualization method for rockburst assessment of deep and long tunnels based on BIM model, characterized by: The following steps are involved: S1, establishing a BIM model with a three-dimensional geological model of the tunnel site; establishing a tunnel model segmented by a preset length based on the three-dimensional geological model of the tunnel site in the BIM model; the preset length segment is less than 100 meters; S2, importing the BIM model into a three-dimensional finite difference program for meshing, obtaining simulation parameters of geotechnical physical parameters, performing geostress inversion on the BIM model, and obtaining the three-dimensional geostress distribution of the tunnel site; S3, inputting the distribution of geostress into the BIM model, and dividing the high geostress area of ​​the BIM model according to the threshold value; S4, dividing the BIM model into potential rockburst sections and performing rockburst grade assessment according to the preset length segments, and changing the graphic element information of the BIM model in the potential rockburst section according to the potential rockburst section division and / or rockburst grade assessment results; The step of establishing a BIM model with a three-dimensional geological model of the tunnel site in S1 specifically includes: establishing a BIM model with a three-dimensional geological model of the tunnel site according to the lithology, surrounding rock type and geological structure in the geological survey data of the tunnel area to be evaluated; In S1, the tunnel model includes geological features and tunnel design parameter information including tunnel site lithology information, surrounding rock grade information, rock mass mechanics information, contour elevation information, tunnel burial depth information, and tunnel size information; The S3 specifically includes: S31, calculating the average value of the ground stress in each preset length segment of the tunnel model according to the ground stress distribution, and inputting it into the BIM model; S32, dividing the high ground stress area of ​​the BIM model according to the threshold value.

2. The BIM model-based deep-buried long tunnel rockburst assessment visualization method according to claim 1, characterized in that: After step S4 is executed, the method further comprises the following steps: S5, conduct tunnel excavation numerical simulation on the BIM model, and make recommendations on the excavation method in combination with finite element numerical analysis.

3. The BIM model-based deep-buried long tunnel rockburst assessment visualization method according to claim 1, characterized in that: When the BIM model is divided into potential rockburst sections and rockburst grade assessment according to the preset length segments in step S4, if the BIM model in the preset length segment is a high stress area, then the BIM model is divided into potential rockburst sections and rockburst grade assessment according to the second preset length segment in the preset length segment; The second preset length segment is smaller than the preset length segment.

4. The BIM model-based deep-buried long tunnel rockburst assessment visualization method according to claim 1, characterized in that: The method of rockburst segmentation and rockburst grade assessment in step S4 specifically includes: Rockburst section division: rockburst section division is carried out according to high ground stress area, surrounding rock type, tunnel burial depth information, surrounding rock grade information and rock mass mechanics information; Rockburst level assessment: rock strength stress ratio method or rock stress intensity ratio method is used to conduct rockburst level assessment. Rockburst level assessment includes five categories: no rockburst, slight rockburst, moderate rockburst, strong rockburst and extremely strong rockburst.

5. The BIM model-based deep-buried long tunnel rockburst assessment visualization method according to claim 4, characterized in that: The method of changing the graphic element information of the BIM model in the potential rockburst section according to the potential rockburst section division and / or rockburst grade assessment result in step S4 specifically includes: In the BIM model, rockburst level assessment results from no rockburst to extremely strong rockburst are displayed in a color gradient manner.

6. The method for visualizing rockburst assessment of a deep and long tunnel based on a BIM model according to any one of claims 1 to 5, characterized in that: The three-dimensional finite difference program in step S2 is FLAC3D software.

7. The BIM model-based deep-buried long tunnel rockburst assessment visualization method according to claim 6, characterized in that: Step S2 specifically includes the following steps: Import the 3D geological BIM model of the tunnel site into FLAC3D software for mesh division and mesh encryption; The simulation parameters of the geotechnical physical parameters are obtained through indoor tests and recommended values ​​of the geotechnical physical parameters in the geological survey report; In the FLAC3D software, the five faces of the BIM model, namely, bottom, left, right, front and back, were fixed, taking into account the self-weight of the rock mass layer overlying the tunnel; The in-situ stress inversion is carried out using the Mohr-Coulomb elastoplastic constitutive model to obtain the calculated value of the in-situ stress distribution in the tunnel site. Based on the calculated value of the geostress distribution in the tunnel site area and combined with the measured geostress data of the engineering deep hole hydraulic fracturing method, the three-dimensional geostress distribution in the tunnel site area is obtained.

8. The BIM model-based deep-buried long tunnel rockburst assessment visualization method according to claim 7, characterized in that: The simulation parameters of the geotechnical physical parameters include elastic modulus, Poisson's ratio, shear modulus, residual strength, cohesion and internal friction angle.

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