A method for monitoring surface directional grouting of deep-buried tunnel or tunnel

Abstract

The application discloses a kind of deep-buried tunnel or tunnel surface directional grouting monitoring methods, comprising: S1, signal hole is arranged: signal hole is arranged in front of L-shaped grouting hole, and detection device is lowered to weak broken stratum in signal hole;S2, drill L-shaped grouting hole;S3, the monitoring collection of broken zone stratum information: including stratum information of three time periods before grouting, during grouting and after grouting;S4, stratum information data analysis and result output: the grouting diffusion law monitored is introduced into the geological model established, and the three-dimensional diffusion effect of grouting is directly reflected.This application can be implemented using existing signal hole or geological hole, reduce monitoring cost;Detection device is arranged in broken stratum, does not affect grouting hole construction, can obtain the change of stratum in real grouting process and diffusion law, to provide monitoring method for deep-buried tunnel surface grouting, to provide analysis basis for deep-buried grouting process and grouting mechanism analysis.

Description

Technical Field

[0001] This invention relates to the field of rock mass grouting monitoring technology. Specifically, it relates to a method for monitoring directional grouting at the surface of deeply buried tunnels or tunnels. Background Technology

[0002] Advanced surface grouting technology, as a method for water plugging and soil reinforcement, has been increasingly used in engineering projects because it does not interfere with underground construction and can pre-treat the tunnel interior. However, due to the technological characteristics of this advanced grouting reinforcement technology, it is difficult to deploy relevant monitoring instruments to comprehensively analyze the grouting process. Therefore, the analysis of its grouting reinforcement mechanism and grouting effect is delayed. Most analytical methods are still based on the working face excavated within the tunnel and laboratory tests.

[0003] CN202410146491.4 discloses a method and system for monitoring grouting pressure under slabs. CN202311179475.7 provides a method and device for monitoring the grouting effect in coal mine surface areas. CN202011527120.9 discloses a method, system, and device for monitoring the diffusion area of ​​grout in rock and soil. CN202310389628.4 provides a grouting monitoring device and a grouting method for goaf grouting. CN201610035140.1 discloses a three-dimensional monitoring system and method for grout diffusion. The above patents are mainly based on indoor or working face grouting reinforcement monitoring and analysis, making it difficult to obtain real data on grouting in deeply buried strata, especially the grout diffusion law and reinforcement mechanism under different grouting pressures in deeply buried strata. There is a lack of real data to guide technological advancements and mechanism research. In order to accurately reveal the water-blocking and reinforcement mechanism and effect of surface grouting in deep-buried tunnels, it is urgent to propose a grouting monitoring method with high feasibility and accurate data, so as to provide a basis for the research of digital twin technology and grouting mechanism. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a method for monitoring directional grouting on the surface of deep-buried tunnels or tunnels, so as to solve the problems of lag in grouting effect analysis, inaccurate grouting monitoring, and difficulty in implementing monitoring operations with existing methods.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for monitoring directional grouting on the surface of deeply buried tunnels or tunnels, comprising the following steps:

[0006] S1. Arrange signal holes: Determine the location of the fracture zone, arrange signal holes in front of the vertical section of the L-shaped grouting hole along the drilling direction of the deep-buried tunnel or tunnel, and lower the detection device into the weak and fractured strata inside the signal hole.

[0007] S2. Drilling L-shaped grouting holes: Drill holes according to the designed L-shaped grouting holes and make inclined holes to the soft and broken strata of the deep buried tunnel or tunnel. Lower the casing to form the hole for wall protection. Place the grout stop plug at the grouting position inside the casing.

[0008] S3. Monitoring and collection of stratigraphic information in fractured zones: Before grouting in L-shaped grouting holes, during grouting, and after grouting, stratigraphic information of weak and fractured strata is collected using a detection device.

[0009] S4. Stratigraphic Information Data Analysis and Result Output: Analyze the stratigraphic information collected in step S3 to obtain the grouting diffusion range and grouting diffusion rate; import the obtained grouting diffusion range and grouting diffusion rate into the established geological model to obtain a three-dimensional diffusion effect diagram of the grouting.

[0010] Preferably, in step S1, when arranging the signal hole, the drilling rig is used to drill vertically into the weak and fractured strata, and the bottom of the signal hole is located above the horizontal section of the L-shaped grouting hole; the signal hole includes a casing section and a bare hole section from top to bottom; after drilling is completed, the casing is lowered into the casing section to fix the hole wall, and the detection device is lowered to the bottom of the bare hole section of the signal hole by cable hoisting.

[0011] Preferably, in step S1, the bottom of the signal hole is located 5 to 10 m above the horizontal section of the L-shaped grouting hole; the length of the bare hole section of the signal hole is 10 to 20 m; retaining a bare hole section of 10 to 20 m in length makes it easier for the detection device to collect more accurate and true formation information.

[0012] Preferably, in step S1, along the drilling direction of the deep-buried tunnel or tunnel: the signal holes are evenly distributed within the extension range of the weak and fractured strata; the distance between two adjacent signal holes is 50 to 60 m, and the horizontal distance between the first signal hole in front of the L-shaped grouting hole and the vertical section of the L-shaped grouting hole is 50 to 100 m.

[0013] Preferably, the detection device is a split-type data sensor; the split-type data sensor includes a signal transmitter and a signal receiver; the signal transmitter is placed in the signal hole, and the signal receiver is arranged in the L-shaped grouting hole, and is lowered into the horizontal section of the L-shaped grouting hole along with the grout stop plug, and the position of the signal receiver is 50-100m away from the position of the signal transmitter.

[0014] Preferably, the detection device is an integrated data sensor; the integrated data sensor includes a signal transmitting module and a signal receiving module, and the signal transmitting module and the signal receiving module are connected by a screw and lowered into the signal hole.

[0015] Preferably, the outer casing and detection module of the above-mentioned detection device adopt a corrosion-resistant and sealed structure, and are protected by waterproof sealing rings and anti-corrosion coatings.

[0016] Preferably, in step S3, the collection of formation information after grouting is completed is carried out continuously from the time the grouting stops at the L-shaped grouting hole until the grout solidifies and stops spreading.

[0017] Preferably, in step S3 above, the collected formation information includes resistivity, voltage, current, frequency, and waveform information.

[0018] Preferably, in step S4 above, the method for judging the grouting effect based on the resistivity change in the formation information is as follows: the resistivity is calculated based on the monitored voltage and current, and the filling rate of the grouting slurry is judged based on the rate of change of resistivity; the relationship between the rate of change of resistivity and the filling rate of the grouting slurry is as follows:

[0019]

[0020] In the formula, The rate of change of resistivity; The resistivity of the water-bearing fissures before grouting; is the resistivity of the solidified slurry; S is the filling rate of the slurry in the crack.

[0021] The method for judging the grouting effect based on frequency changes in stratigraphic information is as follows: For the low-frequency band of stratigraphic information collected before grouting (frequency less than or equal to 100Hz): it is sensitive to pore fluids. After grouting, the water content in the medium decreases, and the current amplitude attenuates. The characteristic frequency band is identified and analyzed, and the grouting effect is evaluated based on the current attenuation amplitude. The larger the current attenuation amplitude, the better the grouting effect. For the high-frequency band of stratigraphic information collected before grouting (frequency greater than or equal to 1kHz): it is sensitive to changes in the rock mass skeleton. After grouting solidification, the signal penetration ability is enhanced. The characteristic frequency band is identified and analyzed, and the effect is evaluated based on the increase in resistivity. The larger the increase in resistivity, the better the rock mass reinforcement effect.

[0022] The method for judging the grouting effect based on waveform changes in formation information is as follows: the higher the waveform distortion rate before grouting, the stronger the inhomogeneity of the medium; as the grout is injected, the inhomogeneity of the medium decreases, the waveform approaches a sine wave, and the total harmonic distortion decreases; the diffusion radius of the grout and the grouting diffusion range are quantified by quantifying the reduction of total harmonic distortion.

[0023] Because the diffusion rate of grout varies at different spatial angles within the same location, this invention calculates the grout diffusion rate based on changes in formation pressure, grouting pressure, and formation information. The grout diffusion rate can be approximated by observing changes in formation information. Taking resistivity as an example: if the resistivity at a certain location before grouting changes by more than or equal to 20% at a certain time during grouting (this could be due to water being squeezed out or grout diffusing to that location), the grout diffusion rate is the ratio of the distance from that location to the bottom grout stop plug to the time elapsed.

[0024] The technical solution of the present invention achieves the following beneficial technical effects:

[0025] 1. This invention places the detection device in a soft and fractured stratum, without affecting the construction of the grouting hole, and can obtain the actual changes and diffusion patterns of the stratum during the grouting process. It solves the problem that existing analysis methods are insufficient to truly reveal the grouting reinforcement mechanism of deep-buried tunnels or tunnels. At the same time, it provides accurate data for digital twin technology and promotes the advancement of surface grouting reinforcement technology for deep-buried tunnels or tunnels.

[0026] 2. This invention can accurately monitor deeply buried strata, solving the problems of inaccurate grouting monitoring and the difficulty of implementation with existing methods. It provides a monitoring method for surface grouting in deep-buried tunnels and provides an analytical basis for the analysis of deep-buried grouting technology and grouting mechanism.

[0027] 3. This invention can utilize existing geological boreholes as signal boreholes for implementation, eliminating the need to drill new boreholes or reducing the number of boreholes required, thus further reducing monitoring costs. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the surface directional grouting monitoring process for deep-buried tunnels or tunnels in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram showing the arrangement of L-shaped grouting holes and signal holes in an embodiment of the present invention.

[0030] The reference numerals in the diagram are as follows: 1-Drilling rig; 2-Mountain; 3-L-shaped grouting hole; 4-Signal hole; 5-Detection device; 6-Weak and fractured strata; 7-Deeply buried tunnel or tunnel. Detailed Implementation

[0031] This embodiment is described in conjunction with the accompanying drawings during implementation.

[0032] like Figure 1 As shown, a method for monitoring directional grouting on the surface of deeply buried tunnels or tunnels includes the following steps:

[0033] S1. Setting up signal holes: First, determine the location of the fault zone. Generally, the reinforcement zone for the fault area is 200m. Signal hole 4 (an existing geological hole) is placed 50-100m in front of the vertical section of L-shaped grouting hole 3. Drilling rig 1 drills vertically into the weak and fractured stratum 6, with a drilling depth of 5-10m above the horizontal section of L-shaped grouting hole 3. Signal hole 4 includes a casing section and a bare hole section from top to bottom. The length of the bare hole section of signal hole 4 is 10-20m. After drilling is completed, the casing is lowered into the casing section to fix the hole wall. The detection device 5 is lowered into the weak and fractured stratum 6 via cable hoisting in signal hole 4. The final lowering position of the signal detector is the bare hole, i.e., facing the actual geological environment. In this embodiment, the detection device 5 is an integrated data sensor; the integrated data sensor includes a signal transmitting module and a signal receiving module, and the signal transmitting module and the signal receiving module are connected by a screw and lowered to the bottom of the bare hole section inside the signal hole 4; the transmitting signal source and receiving source of this detection device can receive signals in the range of 50 to 100m. Although it cannot obtain the entire grouting range, it can obtain the law of grouting diffusion, thereby reflecting the real grouting process and analyzing the subsequent grouting reinforcement effect.

[0034] The receiving signal is debugged to obtain information such as resistivity within a certain range of the fractured zone before grouting. If necessary, anti-shielding measures are implemented for the detection device 5, such as using a corrosion-resistant sealed structure for the outer shell and detection module, and employing waterproof sealing rings and anti-corrosion coatings for anti-shielding measures to effectively ensure signal stability and accuracy. In this embodiment, such as... Figure 2 As shown, the detection device 5 uses an integrated data sensor and is placed in an open borehole, facing the real geological environment. The monitoring point is closer to the diffusion area, and the monitoring effect is more accurate. This method can monitor the diffusion and reinforcement characteristics of the strata throughout the grouting process, and provides a reliable operation method for evaluating the mechanism and effect of directional drilling grouting in deep-buried tunnels.

[0035] In some other embodiments, if a large grouting range is required along the drilling direction of the deep-buried tunnel or tunnel 7, multiple signal holes are evenly distributed in front of the vertical section of the L-shaped grouting hole 3 and along the extension range of the weak and fractured stratum 6 above the horizontal section of the L-shaped grouting hole 3. The distance between two adjacent signal holes 4 is 50 to 60 m, and the distance between the first signal hole 4 in front of the L-shaped grouting hole 3 and the L-shaped grouting hole 3 is 50 to 100 m, so as to further monitor the diffusion pattern of the entire section.

[0036] In some other embodiments, a split-type data sensor can be used as the detection device 5. The split-type data sensor includes a signal transmitter and a signal receiver. The signal transmitter is placed at the bottom of the bare hole section of the signal hole 4, and the signal receiver is arranged in the L-shaped grouting hole 3. It is placed in the horizontal section of the L-shaped grouting hole 3 along with the stop plug. The position of the signal receiver is 50 to 100 m away from the position of the signal transmitter.

[0037] S2. Drilling L-shaped grouting holes 3: L-shaped grouting holes 3 are formed by drilling L-shaped holes on the ground surface, creating inclined holes to the soft and fractured strata 6 of the deep-buried tunnel or tunnel 7, lowering the casing for wall protection and hole formation, and placing the grout stop plug at the grouting position inside the casing for grouting; if a split-type data sensor is used as a detection device, the signal receiver of the detection device is also arranged in the stratum when the grout stop plug is lowered.

[0038] S3. Monitoring and collection of information on the fractured zone: Grouting is carried out in L-shaped grouting holes 3. At the same time, the grouting diffusion law is monitored, including the formation resistivity, voltage, current, frequency and waveform at three time periods: before grouting, during grouting and after grouting.

[0039] S4. Stratigraphic Information Data Analysis and Result Output: By comparing and analyzing the stratigraphic information at three time periods—before grouting, during grouting, and after grouting—the grouting diffusion range and grouting diffusion rate are obtained, thus revealing the grouting diffusion law. The monitored grouting diffusion law is then imported into the established geological model to intuitively reflect the three-dimensional diffusion effect of grouting, thereby guiding grouting production.

[0040] Taking resistivity as an example, since grouting fills the cracks and reduces resistivity, the resistivity of the surrounding rock within the monitoring range decreases in real time during the grouting process. By comparing the magnitude of the resistivity decrease before and after, the grouting diffusion range and diffusion rate can be determined, thereby revealing the true grouting diffusion law.

[0041] Grouting diffusion law refers to the diffusion space and distance of strata with different lithologies and fracture development levels under different grouting process parameters (pressure, grout type) as grouting time changes. Taking the resistivity of a stratum as an example, the data obtained show the characteristics of stratum resistivity changes at different times. Then, based on the background value of stratum resistivity, the filling effect and spatial distribution characteristics of the grout are obtained.

[0042] The relationship between monitored geological information and grout diffusion:

[0043] 1. Resistivity is calculated by monitoring voltage and current. The core of the grouting diffusion law is to establish the resistivity change rate (…). Quantitative relationship between resistivity change rate and slurry filling rate (S). Relationship between resistivity change rate and filling rate:

[0044]

[0045] in: : Resistivity of water-bearing fractures before grouting (low value); : Resistivity of the solidified slurry (high value, typically >100 Ω·m); S: Filling rate of the slurry in the cracks (0~100%); Elevation of resistivity ∝S. The higher the slurry filling rate, the greater the increase in resistivity.

[0046] 2. Frequency:

[0047] For the low-frequency band (frequency ≤100Hz in the formation information collected before grouting): it is sensitive to pore fluids. After grouting, the water content in the medium decreases and the current amplitude attenuates. The characteristic frequency band is identified and analyzed. The effect is evaluated based on the current attenuation amplitude. The larger the current attenuation amplitude, the better the grouting effect.

[0048] For high-frequency bands (frequency ≥1kHz in the stratigraphic information collected before grouting): these bands are sensitive to changes in the rock mass framework, and the signal penetration ability is enhanced after grouting and solidification. Characteristic frequency bands are identified and analyzed, and the effect is evaluated based on the increase in resistivity; the greater the increase in resistivity, the better the rock mass reinforcement effect.

[0049] 3. Waveform;

[0050] Before grouting, the waveform distortion rate is high and the medium is highly inhomogeneous. As the grout is injected, the inhomogeneity of the medium decreases, the waveform approaches a sine wave, and the total harmonic distortion (THD) decreases. By quantifying the THD reduction, the diffusion radius of the grout can be quantified, thereby obtaining the grout diffusion range.

[0051] Because the diffusion rate of grout varies at different spatial angles within the same location, this invention calculates the grout diffusion rate based on changes in formation pressure, grouting pressure, and formation information. The grout diffusion rate can be approximated by observing changes in formation information. Taking resistivity as an example: if the resistivity at a certain location before grouting changes by more than or equal to 20% at a certain time during grouting (this could be due to water being squeezed out or grout diffusing to that location), the grout diffusion rate is the ratio of the distance from that location to the bottom grout stop plug to the time elapsed.

[0052] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for monitoring directional grouting on the surface of deeply buried tunnels or tunnels, characterized in that, Includes the following steps: S1. Arrange signal holes (4): Determine the location of the fracture zone, arrange signal holes (4) in front of the vertical section of the L-shaped grouting hole (3) along the drilling direction of the deep-buried tunnel or tunnel (7), and lower the detection device (5) into the weak and fractured stratum (6). S2. Drilling L-shaped grouting holes (3): Drill holes according to the designed L-shaped grouting holes (3) and make inclined holes to the soft and broken strata (6) of the deep buried tunnel or tunnel (7), lower the casing to form the hole for wall protection, and put the grout stop plug at the grouting position in the casing. S3. Monitoring and collection of stratigraphic information of fractured zone: Before grouting, during grouting and after grouting in L-shaped grouting hole (3), stratigraphic information of weak fractured strata (6) is collected by detection device (5); S4. Stratigraphic Information Data Analysis and Result Output: Analyze the stratigraphic information collected in step S3 to obtain the grouting diffusion range and grouting diffusion rate; The grouting diffusion range and grouting diffusion rate obtained from the analysis are imported into the established geological model to obtain a three-dimensional diffusion effect diagram of the grouting. In step S1, when setting up the signal hole (4), the drilling rig (1) is used to drill vertically into the weak and broken stratum (6). The bottom of the signal hole (4) is located above the horizontal section of the L-shaped grouting hole (3). The signal hole (4) includes a casing section and a bare hole section from top to bottom. After drilling is completed, the casing is lowered to fix the hole wall in the casing section, and the detection device (5) is lowered to the bottom of the bare hole section of the signal hole (4) by cable hoisting. In step S3, the collected formation information includes resistivity, voltage, current, frequency, and waveform information; In step S4, the method for judging the grouting effect based on the resistivity change in the formation information is as follows: The resistivity is calculated based on the monitored voltage and current, and the filling rate of the grout is determined based on the rate of change of resistivity; the relationship between the rate of change of resistivity and the filling rate of the grout is as follows: In the formula, The rate of change of resistivity; The resistivity of the water-bearing fissures before grouting; The resistivity of the solidified slurry; S This represents the filling rate of the grout in the crack; The method for judging the grouting effect based on frequency changes in stratigraphic information is as follows: For the low-frequency band of stratigraphic information collected before grouting (frequency less than or equal to 100Hz): it is sensitive to pore fluids. After grouting, the water content in the medium decreases, and the current amplitude attenuates. The characteristic frequency band is identified and analyzed, and the grouting effect is evaluated based on the current attenuation amplitude. The larger the current attenuation amplitude, the better the grouting effect. For the high-frequency band of stratigraphic information collected before grouting (frequency greater than or equal to 1kHz): it is sensitive to changes in the rock mass skeleton. After grouting solidification, the signal penetration ability is enhanced. The characteristic frequency band is identified and analyzed, and the effect is evaluated based on the increase in resistivity. The larger the increase in resistivity, the better the rock mass reinforcement effect. The method for judging the grouting effect based on waveform changes in formation information is as follows: the higher the waveform distortion rate before grouting, the stronger the inhomogeneity of the medium; as the grout is injected, the inhomogeneity of the medium decreases, the waveform approaches a sine wave, and the total harmonic distortion decreases; the diffusion radius of the grout and the grouting diffusion range are quantified by quantifying the reduction of total harmonic distortion. The grouting diffusion rate is calculated based on the variation values ​​of formation pressure, grouting pressure, and formation information.

2. The method for monitoring directional grouting on the surface of deep-buried tunnels or tunnels according to claim 1, characterized in that, In step S1, the bottom of the signal hole (4) is located 5 to 10 m above the horizontal section of the L-shaped grouting hole (3); the length of the bare hole section of the signal hole (4) is 10 to 20 m.

3. The method for monitoring directional grouting on the surface of deep-buried tunnels or tunnels according to claim 1, characterized in that, In step S1, along the drilling direction of the deep-buried tunnel or tunnel (7): the signal holes (4) are evenly distributed within the extension range of the weak and fractured strata (6); the distance between two adjacent signal holes (4) is 50 to 60 m, and the horizontal distance between the first signal hole (4) in front of the L-shaped grouting hole (3) and the vertical section of the L-shaped grouting hole (3) is 50 to 100 m.

4. The method for monitoring directional grouting on the surface of deep-buried tunnels or tunnels according to claim 1, characterized in that, The detection device (5) is a split data sensor; the split data sensor includes a signal transmitter and a signal receiver; the signal transmitter is placed in the signal hole (4), and the signal receiver is arranged in the L-shaped grouting hole (3), and is placed in the horizontal section of the L-shaped grouting hole (3) along with the grout stop plug, and the position of the signal receiver is 50-100m away from the position of the signal transmitter.

5. The method for monitoring directional grouting on the surface of deep-buried tunnels or tunnels according to claim 1, characterized in that, The detection device (5) is an integrated data sensor; the integrated data sensor includes a signal transmitting module and a signal receiving module, and the signal transmitting module and the signal receiving module are connected by a screw and then lowered into the signal hole (4).

6. The method for monitoring directional grouting on the surface of deep-buried tunnels or tunnels according to claim 1, characterized in that, The outer shell and detection module of the detection device (5) are both made of corrosion-resistant and sealed structure, and are protected by waterproof sealing rings and anti-corrosion coating.

7. The method for monitoring directional grouting on the surface of deep-buried tunnels or tunnels according to claim 1, characterized in that, In step S3, after grouting is completed, the collection of formation information is carried out by continuously collecting data after grouting stops at the L-shaped grouting hole (3) until the grout solidifies and no longer diffuses.

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