A TSP and FLAC3D combined early warning method to prevent TBM jams

Abstract

The invention discloses an early warning method for preventing TBM jams by combining TSP and FLAC3D. The method can provide early warning for possible TBM jams based on the fast pressure speed and deformation speed of tunnel surrounding rocks, combined with the synergistic effect of TSP and FLAC3D, and includes the following steps: a. determining a tunnel section that may produce large deformation of surrounding rocks; b. determining the mechanical parameters of the surrounding rocks of the tunnel section; c. using TSP to monitor the wave velocity of surrounding rocks and the geological conditions of surrounding rocks ahead, and making an initial prediction of the possible jam risks of TBM; d. using FLAC3D to simulate the stress and strain of tunnel surrounding rocks; e. combining the wave velocity change of TSP and the stress and strain law of tunnel surrounding rocks simulated by FLAC3D to classify the pressure speed, deformation speed and deformation amount of surrounding rocks; and f. providing early warning for possible jam risks of TBM based on the classification results.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering and other underground engineering construction, and in particular to an early warning method for preventing TBM jams by combining TSP and FLAC3D. Background Art

[0002] With the development of science and technology, the development of underground engineering to deep ground has become an urgent need. More and more deep buried long tunnels are gradually emerging around the world, and TBM is being used more and more widely in these underground projects. Deep tunnel TBM often encounters surrounding rocks such as high ground stress and weak rock mass during excavation, which makes the shield easily stuck, such as the Dianzhong Water Diversion Project and the Yellow River Diversion Project. TBM jamming includes cutterhead jamming and shield jamming. Cutterhead jamming mainly occurs in the surrounding rock fracture zone, and is usually handled by the instantaneous release torque of the cutterhead (which can reach about 1.7 times the rated torque). Shield jamming refers to the jamming of the TBM shield due to large deformation of the surrounding rock, and the resistance caused by the surrounding rock stress acting on the shield exceeds the TBM escape thrust. This accident usually occurs in caverns with high ground stress and weak surrounding rock. As time goes by, the TBM shield is stuck tighter and tighter, mainly because the surrounding rock deformation continues to increase with time, that is, the surrounding rock deformation has significant rheological characteristics.

[0003] Faced with complex and ever-changing underground projects, there is still no strong theoretical and technical support for early warning of TBM jam risks. TSP and FLAC3D are commonly used equipment and simulation software in the field of underground engineering. TSP (tunnel seismic prediction) tunnel seismic wave prediction exploration is a set of advanced geological prediction system equipment developed by the Swiss Amberg Measurement Technology Company in the early 1990s. The principle is seismic wave reflection method. The purpose is to be used in the process of tunnel construction to make long-distance advance predictions of uncertain unfavorable geological bodies (such as fractured zones and faults) in front of the tunnel face. Its reliable prediction range is about 100~150m in front of the face, and can reach more than 200m in hard rocks with good geological conditions. Flac3D is a powerful engineering three-dimensional analysis software. The software provides users with rich modeling and analysis tools. Users can solve various complex mechanical and geotechnical problems through functions such as numerical analysis and geotechnical analysis. Develop a TBM jam early warning method that combines TSP and FLAC3D, combining the two to give full play to their strengths, and become a new concept for predicting TBM jam risks. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an early warning method for preventing TBM jams by combining TSP and FLAC3D, which can combine TSP and FLAC3D to provide a more accurate early warning of TBM jam risks.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A TSP and FLAC3D combined early warning method for preventing TBM jams is designed, including the following steps:

[0007] a. Determine the tunnel sections that may cause large deformation of the surrounding rock: obtain data through on-site geological reports and tectonic movement theory, and determine the locations that require TBM jam warning based on the geological information and support methods of the tunnel sections that may cause large deformation of the surrounding rock;

[0008] b. Determine the mechanical parameters of the surrounding rock of the tunnel section: Determine the mechanical properties and deformation laws of the surrounding rock by measuring the relevant basic mechanical parameters of the surrounding rock, and prepare for subsequent numerical simulation;

[0009] c. Use TSP to monitor the wave velocity of the surrounding rock and the geological conditions of the surrounding rock in front, and make an initial prediction of the risk of TBM getting stuck: Use the advanced geological prediction equipment TSP to monitor the wave velocity changes of the surrounding rock, and at the same time detect the nature, location and scale of the unfavorable geological body in front of the tunnel working face; and classify the surrounding rock to make an initial prediction of whether the TBM will encounter the risk of getting stuck during the excavation process; the geological conditions of the surrounding rock in front include different geological conditions such as weak zones, broken zones, faults, and water.

[0010] d. Use FLAC3D to simulate the stress and strain of the tunnel surrounding rock: According to the mechanical parameters of the tunnel section, numerical simulation is carried out to find the stress and strain law after the tunnel is excavated, as well as the speed of large deformation or creep of the surrounding rock and the time of maximum deformation, as well as the time of the first pressure of the surrounding rock. The surrounding rock is divided into grades for secondary prediction of whether the TBM will encounter the risk of jamming during the excavation process;

[0011] e. Classify the surrounding rock pressure velocity, deformation velocity and deformation amount by combining the wave velocity change of TSP and the stress-strain law of tunnel surrounding rock simulated by FLAC3D: conduct a comprehensive analysis based on the properties of the adverse geological body in front of the tunnel working face detected by advanced geological prediction and the surrounding rock stress-strain law obtained by numerical simulation; compare the TBM's excavation speed and reserved deformation amount with the surrounding rock deformation speed and deformation amount monitored by TSP and FLAC3D; thus make a third prediction on whether the TBM will encounter the risk of machine jam during the excavation process;

[0012] f. Issue early warnings for possible TBM jam risks based on the grading results: Based on the results of the previous three predictions, the prediction results are divided into three levels: jam, possible jam, and no jam, to issue early warnings for possible TBM jam risks.

[0013] Furthermore, the basic mechanical parameters determined in step b include uniaxial compressive strength, shear / tensile strength, elastic modulus, cohesion, and internal friction angle.

[0014] Furthermore, in step f, when the TBM passes through a tunnel section with large deformation of the surrounding rock, the deformation of the surrounding rock is less than the reserved deformation of the TBM, the initial pressure time is long, and no unfavorable geological body is encountered. It is judged that the TBM should not encounter the risk of jamming during the excavation process.

[0015] Furthermore, in step f, when the TBM passes through a tunnel section with large deformation of the surrounding rock, the surface deformation of the tunnel surrounding rock is greater than the reserved deformation of the TBM, then it is determined that the TBM will encounter a risk of getting stuck during the excavation process.

[0016] Furthermore, in step f, when the TBM passes through a tunnel section with large deformation of the surrounding rock, the surface deformation of the tunnel surrounding rock is close to the reserved deformation of the TBM, and the initial pressure of the surrounding rock after excavation is fast, less than 24 hours, it is judged that the TBM may encounter a risk of jamming during the excavation process.

[0017] Furthermore, in step f, when the TBM passes through a tunnel section with large deformation of the surrounding rock, the surface deformation of the tunnel surrounding rock is close to the reserved deformation of the TBM, and the periodic pressure will cause deformation of the surrounding rock; at this time, if the TBM excavation speed is too slow and fails to pass through the tunnel section with large deformation of the surrounding rock in time, the TBM will encounter the risk of getting stuck during the excavation process.

[0018] Furthermore, in step f, when the TBM passes through a tunnel section with large deformation of the surrounding rock, if there are unfavorable geological bodies such as caves, faults, and fracture zones in front of the heading face that are prone to cause surrounding rock collapse, the TBM may encounter the risk of getting stuck during excavation.

[0019] The beneficial effects of the present invention are:

[0020] The present invention conducts a comprehensive analysis based on the properties of the adverse geological bodies (weak zones, broken zones, faults, water content, etc.) in front of the tunnel working face detected by advanced geological prediction and the stress-strain law of the surrounding rock obtained by numerical simulation, and compares the excavation speed and reserved deformation of the TBM with the deformation speed and deformation of the surrounding rock monitored by TSP and FLAC3D, so as to conduct a scientific analysis and prediction; the prediction results are divided into three levels: machine jam, possible machine jam, and no machine jam, and the possible machine jam risk of the TBM is warned. This warning method can target the risks brought by the rapid deformation of the surrounding rock that may be encountered during the excavation of the TBM in all underground projects, effectively avoid the risk of machine jam or other disaster prevention risks caused by large deformation of the surrounding rock, and is of great significance for promoting the safe, rapid and efficient excavation of TBM tunnels. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1The present invention is a flow chart of an early warning method for preventing TBM jams by combining TSP and FLAC3D. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention is described below in conjunction with examples, but the following examples are only used to illustrate the present invention in detail and do not limit the scope of the present invention in any way. Unless otherwise specified, the equipment components involved in the following examples are all conventional equipment components.

[0023] Embodiment 1: A TSP and FLAC3D combined early warning method for preventing TBM jams, comprising the following steps:

[0024] a. Determine the tunnel sections that may cause large deformation of the surrounding rock: obtain data through on-site geological reports and tectonic movement theory, and determine the locations that require TBM jam warnings based on the geological information and support methods of the tunnel sections that may cause large deformation of the surrounding rock.

[0025] b. Determine the mechanical parameters of the surrounding rock of this tunnel section: Determine the mechanical properties and deformation laws of the surrounding rock by measuring its uniaxial compressive strength, shear (tensile) strength, elastic modulus, cohesion, internal friction angle and other basic mechanical parameters, and prepare for subsequent numerical simulation.

[0026] c. Use TSP to monitor the wave velocity of the surrounding rock and the geological conditions of the surrounding rock in front, and make an initial prediction of the risk of TBM getting stuck. Use the advanced geological prediction equipment TSP to monitor the wave velocity changes of the surrounding rock, and at the same time detect the nature (weak zone, broken zone, fault, water content, etc.) and location and scale of the unfavorable geological body in front of the tunnel working face; and classify the surrounding rock to make an initial prediction of whether the TBM will encounter the risk of getting stuck during the excavation process.

[0027] d. Use FLAC3D to simulate the stress and strain of the tunnel surrounding rock. According to the mechanical parameters of the tunnel section, numerical simulation is carried out to find the stress and strain law after the tunnel is excavated, as well as the speed of large deformation or creep of the surrounding rock and the time of maximum deformation, as well as the time of the first pressure of the surrounding rock. The surrounding rock grade is divided twice, and the second prediction is made on whether the TBM will encounter the risk of jamming during the excavation process.

[0028] e. Combining the wave velocity changes of TSP and the stress-strain law of tunnel surrounding rock simulated by FLAC3D, the surrounding rock pressure velocity, deformation velocity and deformation amount are classified.

[0029] A comprehensive analysis is conducted based on the properties of the adverse geological bodies (weak zones, broken zones, faults, water content, etc.) in front of the tunnel working face detected by advanced geological forecasting and the stress-strain laws of the surrounding rock obtained by numerical simulation; the excavation speed and reserved deformation of the TBM are compared with the deformation speed and deformation of the surrounding rock monitored by TSP and FLAC3D; thus a third prediction is made as to whether the TBM will encounter the risk of getting stuck during the excavation process.

[0030] f. Issue early warnings for possible TBM jam risks based on the grading results: Based on the previous prediction results, the prediction results are divided into three levels: jam, possible jam, and no jam, to issue early warnings for possible TBM jam risks.

[0031] The specific classification standards are:

[0032] (1) When the TBM passes through a tunnel section with large deformation of the surrounding rock, the deformation of the surrounding rock is less than the reserved deformation of the TBM. The initial pressure time is long and no adverse geological body is encountered. It is judged that the TBM should not encounter the risk of machine jam during the excavation process.

[0033] (2) When the TBM passes through a tunnel section with large deformation of the surrounding rock, the deformation of the tunnel surrounding rock surface is greater than the reserved deformation of the TBM, and it is judged that the TBM will encounter a risk of jamming during the excavation process. At this time, it is necessary to prepare in advance to expand the excavation or change the excavation method, or to pre-reinforce the surrounding rock in front of the face.

[0034] (3) When the TBM passes through a tunnel section with large deformation of the surrounding rock, the surface deformation of the tunnel surrounding rock is close to the reserved deformation of the TBM, and the initial pressure of the surrounding rock after excavation is fast, less than 24 hours, it is judged that the TBM may encounter the risk of machine jam during the excavation process. At this time, it is necessary to prepare for the expansion of the excavation in advance and be prepared for the possibility of machine jam.

[0035] (4) When the TBM passes through a tunnel section with large deformation of the surrounding rock, the surface deformation of the tunnel surrounding rock is close to the reserved deformation of the TBM, and the periodic pressure will cause the surrounding rock to deform. At this time, if the TBM excavation speed is too slow and fails to pass through the tunnel section with large deformation of the surrounding rock in time, the TBM will encounter the risk of jamming during the excavation process. At this time, it is necessary to prepare in advance to expand the excavation or change the excavation method, or to reinforce the surrounding rock in front of the face in advance.

[0036] (5) When the TBM passes through a tunnel section with large deformation of the surrounding rock, if there are unfavorable geological bodies such as karst caves, faults, and fracture zones in front of the face that are prone to cause surrounding rock collapse, the TBM may encounter the risk of machine jam during excavation. In this case, it is necessary to prepare for excavation expansion in advance and be prepared for machine jams.

[0037] After judging the results according to the above standards, the warning results will be fed back. The staff can take countermeasures based on the warning results, thereby effectively avoiding the risk of machine jam or other disaster risks caused by large deformation of the surrounding rock, which is of great significance for promoting the safe, rapid and efficient excavation of TBM tunnels.

[0038] The present invention has been described in detail above in conjunction with the embodiments. However, those skilled in the art will appreciate that, without departing from the spirit of the present invention, the specific parameters in the above embodiments may be changed to form a plurality of specific embodiments, which are all within the common variation range of the present invention and will not be described in detail herein.

Claims

1. A TSP and FLAC3D combined early warning method for preventing TBM jams, characterized in that: The following steps are involved: a. Determine the tunnel sections that may cause large deformation of the surrounding rock: obtain data through on-site geological reports and tectonic movement theory, and determine the locations that require TBM jam warning based on the geological information and support methods of the tunnel sections that may cause large deformation of the surrounding rock; b. Determine the mechanical parameters of the surrounding rock of the tunnel section: Determine the mechanical properties and deformation laws of the surrounding rock by measuring the relevant basic mechanical parameters of the surrounding rock, and prepare for subsequent numerical simulation; c. Use TSP to monitor the wave velocity of the surrounding rock and the geological conditions of the surrounding rock ahead, and make an initial prediction of the risk of TBM jamming: Use the advanced geological prediction equipment TSP to monitor the wave velocity changes of the surrounding rock, and at the same time detect the nature, location and scale of the unfavorable geological body ahead of the tunnel working face; and classify the surrounding rock to make an initial prediction of whether the TBM will encounter the risk of jamming during the excavation process; d. Use FLAC3D to simulate the stress and strain of the tunnel surrounding rock: According to the mechanical parameters of the tunnel section, numerical simulation is carried out to find the stress and strain law after the tunnel is excavated, the speed of large deformation or creep of the surrounding rock and the time of maximum deformation, as well as the time of the first pressure of the surrounding rock. The surrounding rock is divided into grades for secondary classification, and the risk of TBM jamming is predicted for the second time during the excavation process; e. Classify the surrounding rock pressure velocity, deformation velocity and deformation amount by combining the wave velocity change of TSP and the stress-strain law of tunnel surrounding rock simulated by FLAC3D: conduct a comprehensive analysis based on the properties of the adverse geological body in front of the tunnel working face detected by advanced geological prediction and the surrounding rock stress-strain law obtained by numerical simulation; compare the TBM's excavation speed and reserved deformation amount with the surrounding rock deformation speed and deformation amount monitored by TSP and FLAC3D; thus make a third prediction on whether the TBM will encounter the risk of machine jam during the excavation process; f. Issue early warnings for possible TBM jam risks based on the grading results: Based on the results of the previous three predictions, the prediction results are divided into three levels: jam, possible jam, and no jam, to issue early warnings for possible TBM jam risks.

2. The early warning method for preventing TBM jams by combining TSP and FLAC3D according to claim 1 is characterized in that: The basic mechanical parameters determined in step b include uniaxial compressive strength, shear / tensile strength, elastic modulus, cohesion, and internal friction angle.

3. The early warning method for preventing TBM jams by combining TSP and FLAC3D according to claim 1 is characterized in that: In step f, when the TBM passes through a tunnel section with large deformation of the surrounding rock, the deformation of the surrounding rock is less than the reserved deformation of the TBM, the initial pressure time is long, and no adverse geological body is encountered. It is judged that the TBM should not encounter the risk of jamming during the excavation process.

4. The early warning method for preventing TBM jams by combining TSP and FLAC3D according to claim 1 is characterized in that: In step f, when the TBM passes through a tunnel section with large deformation of the surrounding rock, the surface deformation of the tunnel surrounding rock is greater than the reserved deformation of the TBM, and it is determined that the TBM will encounter a risk of getting stuck during the excavation process.

5. The early warning method for preventing TBM jams by combining TSP and FLAC3D according to claim 1 is characterized in that: In step f, when the TBM passes through a tunnel section with large deformation of the surrounding rock, the surface deformation of the tunnel surrounding rock is close to the reserved deformation of the TBM, and the initial pressure of the surrounding rock after excavation is fast, less than 24 hours, it is judged that the TBM may encounter a risk of jamming during the excavation process.

6. The early warning method for preventing TBM jams by combining TSP and FLAC3D according to claim 1 is characterized in that: In step f, when the TBM passes through a tunnel section with large deformation of the surrounding rock, the surface deformation of the tunnel surrounding rock is close to the reserved deformation of the TBM, and the periodic pressure will cause deformation of the surrounding rock; At this time, if the TBM excavation speed is too slow and fails to pass through the tunnel section with large deformation of the surrounding rock in time, the TBM will encounter the risk of getting stuck during the excavation process.

7. The early warning method for preventing TBM jams by combining TSP and FLAC3D according to claim 1 is characterized in that: In step f, when the TBM passes through a tunnel section with large deformation of the surrounding rock, if there are unfavorable geological bodies such as karst caves, faults, and fracture zones in front of the face that are prone to cause surrounding rock collapse, the TBM may encounter the risk of getting stuck during excavation.

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