A double-shield TBM advance small-catheter grouting reinforcement construction method

Abstract

The present application relates to the technical field of advanced pipe grouting reinforcement construction, and particularly relates to a double-shield TBM advanced small pipe grouting reinforcement construction method, which comprises the following steps: S1, judging whether the front stratum needs grouting reinforcement based on real-time monitoring of TBM tunneling parameters and advanced geological drilling; S2, establishing a coordinate system with the center of the shield machine face as the base point, and calculating the three-dimensional coordinates of each grouting point on the initial reinforcement surface and the total number of grouting points according to the radius of the shield machine and the slurry diffusion radius; S3, according to the grouting point coordinate position determined in S2, in this scheme, the well is drilled downward from the ground and the pipe is installed, the working environment is safe and spacious, and because the working surface has moved to the ground, the geological environment can be detected in real time during the drilling process, and the grouting reinforcement work is carried out in sections, which is not limited by the length of the pipe, the tunneling operation can be carried out after the reinforcement of the entire reinforcement section is completed, and the problem of intermittent reinforcement and tunneling operation is avoided.

Description

Technical Field

[0001] This invention relates to the field of advanced guide tube grouting reinforcement construction technology, and in particular to a double-shield TBM advanced small guide tube grouting reinforcement construction method. Background Technology

[0002] Double-shield TBMs (tunnel boring machines) are crucial equipment for traversing complex geological formations, especially weak, fractured, or water-rich rock layers. To ensure their safe and continuous excavation, pre-grouting reinforcement of unfavorable geological formations ahead is a vital auxiliary method, designed to improve the surrounding rock in advance and prevent disasters such as collapse and water inrush.

[0003] However, traditional grouting reinforcement work is carried out at the tunnel face, and the reinforcement length is limited. If there are still parts that need reinforcement, the tunnel boring machine needs to complete the tunneling work of the current reinforcement section before reinforcement can be carried out. During this process, the position of the tunnel boring machine needs to be adjusted to provide space for grouting reinforcement work, and the operation is repeated continuously. The process is extremely complicated, time-consuming and labor-intensive.

[0004] To address this, the present invention proposes a double-shield TBM advanced small-diameter guide pipe grouting reinforcement construction method. By drilling from the ground downwards and installing guide pipes, the working environment is safe and spacious. Since the working face is moved to the ground, the geological environment can be monitored in real time during the drilling process. Furthermore, the grouting reinforcement work is carried out in sections without being limited by the length of the guide pipes. The entire reinforcement section can be reinforced before tunneling operations can be carried out, avoiding the problem of intermittent reinforcement and tunneling operations. Summary of the Invention

[0005] The technical problems to be solved include: limited working space, high safety risks, and intermittent operation.

[0006] To address the shortcomings of existing technologies, this invention provides a double-shield TBM advanced small-diameter pipe grouting reinforcement construction method, thereby solving the technical problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for grouting reinforcement using a double-shield TBM with advanced small-diameter guide pipes, the method comprising the following steps:

[0009] S1. Based on real-time monitoring of TBM tunneling parameters and advanced geological drilling, determine whether the strata ahead need grouting reinforcement.

[0010] S2. Establish a coordinate system with the center of the tunnel boring machine face as the base point. Calculate the three-dimensional coordinates of each grouting point on the initial reinforcement surface and the total number of grouting points based on the radius of the tunnel boring machine and the grout diffusion radius.

[0011] S3. Based on the grouting point coordinates determined in S2, determine the number and location of wells by constructing a ground projection, and calculate the drilling depth by using the distance H between the center point of the working face and the projection point A.

[0012] S4. Prepare a guide pipe that matches the drilling depth, and open grouting holes on the guide pipe at the grouting point coordinates determined in S2. The guide pipes located on both sides of the tunnel are full-hole guide pipes with all grouting holes, and the rest are double-hole guide pipes with some grouting holes.

[0013] S5. After the guide pipe is inserted into the well, the stone filling and concrete filling are alternately filled. The uppermost stone filling layer is filled with concrete filling layer between it and the ground. The stone filling layer extends into the borehole section with buffer sections above and below.

[0014] S6. Inject grout into the formation through the conduit. Stop when the grouting pressure reaches the design upper limit and continues to rise.

[0015] S7. Calculate the distance between the second reinforced surface and the initial reinforced surface based on the slurry diffusion radius R. Then, determine the coordinates of the center point of the subsequent reinforcement surface on the Y-axis, repeat step S2 to determine the coordinates of each grouting point on each reinforcement surface, and repeat steps 3 to 6 to carry out drilling, guide pipe installation, backfilling and grouting work.

[0016] In one possible implementation, in step S2, the coordinates of each grouting point are determined by first constructing a three-dimensional coordinate system with the center of the tunnel face of the shield machine as the origin. The coordinate system is based on the tunneling direction of the shield machine as the +y axis. The coordinates of the center point of the initial reinforced surface are obtained by extending the +y axis forward by 1.5 times the grout diffusion radius based on the starting position of the grouting reinforcement.

[0017] In one possible implementation, in step S2, the distances of the grout injection points on the X and Z axes from the center point of the initial reinforced surface are obtained based on the coordinates of the center point of the reinforced surface, the radius D of the tunnel boring machine, and the single-point grout diffusion radius R, and then the coordinates of the grout injection points at the four corners of the initial reinforced surface are determined.

[0018] In one possible implementation, in step S2, the distance L between adjacent angles and the spacing between adjacent points are obtained based on the shield machine radius D and the single-point slurry diffusion radius R. The diameter of the slurry diffusion Then, through the distance L between adjacent corners and the spacing between adjacent points Count the points on one side of the matrix That is, the total number of points in the grouting point matrix. Since the grouting points are evenly arranged along the X and Z axes at intervals d, forming an n×n rectangular frame grid, the coordinates of all grouting points on all initial reinforcement surfaces are determined by the number of grouting points and the coordinates of the grouting points at the four corners of the initial reinforcement surface.

[0019] In one possible implementation, in step S4, the length of the guide pipe is calculated based on the distance H from the center point of the tunnel face to the projection point A, the radius D of the tunnel boring machine, and the single-point grout diffusion radius R. At the same time, the grouting point position is marked on the guide pipe according to the Z-axis direction coordinate sequence in step S2, and the drilling section is marked with the grouting point base point. The drilling is carried out in layers at fixed intervals, and the positions of the upper and lower layers of drilling are set with a fixed deviation angle.

[0020] Beneficial effects compared to existing technologies:

[0021] 1. In this scheme, drilling from the ground downwards and installing guide pipes creates a safe and spacious working environment. More importantly, by distinguishing between full-hole guide pipes and double-hole guide pipes to form a grouting matrix, the grouting area intentionally avoids the core tunneling area directly in front of the tunnel boring machine cutterhead, greatly reducing tunneling resistance and cutterhead wear. This solves the long-standing technical problem of the contradiction between advanced reinforcement and efficient tunneling, and ensures the smooth passage of the TBM through the reinforced area.

[0022] 2. In this scheme, grouting reinforcement is carried out by drilling from the ground down and installing a guide pipe. During the drilling process, the geological environment can be monitored in real time. If the monitoring is unsatisfactory, grouting reinforcement is carried out. If the monitoring is satisfactory, the grouting reinforcement work is completed, thus prompting the tunnel boring machine to start tunneling. This solves the problem of discontinuous grouting reinforcement and tunneling in traditional grouting reinforcement. Traditional grouting reinforcement is carried out at the tunnel face, and its reinforcement length is limited. If there are still parts that need reinforcement, the tunnel boring machine needs to complete the tunneling work of the current reinforcement section before reinforcement is carried out. During this process, the position of the tunnel boring machine needs to be adjusted to provide space for grouting reinforcement work, and the operation is repeated continuously. The process is extremely complicated, time-consuming and labor-intensive. Attached Figure Description

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0024] Figure 1 This is a flowchart of the method steps of the present invention;

[0025] Figure 2 This is a schematic diagram of the working face and the initial reinforcement surface of the present invention;

[0026] Figure 3 This is a schematic diagram illustrating the determination of grouting point coordinates according to the present invention;

[0027] Figure 4 This is a schematic diagram of the ground projection of the present invention;

[0028] Figure 5 This is a schematic diagram of the borehole section of the conduit in this invention;

[0029] Figure 6 This is a schematic diagram of drilling and backfilling using the full-hole guide pipe of the present invention;

[0030] Figure 7 This is a schematic diagram of the drilling backfilling of the dual-hole guide pipe of the present invention. Detailed Implementation

[0031] Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can also be implemented in various different forms, and therefore the present invention is not limited to the embodiments described below.

[0032] The technical solution in this application embodiment is to solve the problems mentioned in the background art, and the overall idea is as follows:

[0033] Example:

[0034] Please refer to Figures 1 to 7 As shown in the figure, this embodiment introduces a method for grouting reinforcement using a double-shield TBM with advanced small guide pipes. The method includes the following steps:

[0035] S1. Real-time soil testing and reinforcement necessity assessment during tunneling.

[0036] S1.1 Real-time monitoring and analysis of TBM tunneling parameters: By continuously collecting core parameters related to shield machine advance speed, total thrust, cutterhead torque, cutterhead rotation speed, and penetration depth, and by establishing parameter baselines based on the current geological conditions of the section, the rate of change of key parameters is calculated in real time for real-time early warning.

[0037] Data acquisition includes thrust, torque, propulsion speed, and penetration depth, specifically:

[0038] The thrust is collected by a pressure sensor installed on the propulsion cylinder, the torque is directly measured by the torque sensor of the drive system, the propulsion speed is calculated by the displacement sensor of the propulsion cylinder per unit time, the cutter head rotation speed is directly measured by the encoder of the cutter head drive system, and the penetration is calculated in real time by the propulsion speed / cutter head rotation speed.

[0039] The key performance indicators (KPIs) are calculated in units of "rings" (the theoretical width of the tunnel boring machine's forward advance in one go, with one ring positioned to assemble a complete circle of tunnel segments), as detailed below:

[0040] Average penetration: The average of all penetration samples during the tunneling of this ring;

[0041] Unit thrust / torque: To eliminate the influence of tunneling speed, the total thrust / tunneling distance or total torque / tunneling distance is often calculated, or the coordinated change trend of thrust-speed and torque-speed is directly analyzed;

[0042] Torque fluctuation coefficient: Take the torque time series data during the stable phase of tunneling in this loop, and calculate the standard deviation of the series ( ) and arithmetic mean ( ),That The higher this value, the more uneven the force on the cutter head.

[0043] Parameter change rate: Calculates the percentage change between the parameter value of the current loop and the average value of the previous N loops (e.g., 5 loops).

[0044] Threshold setting involves establishing a dynamic baseline and comparing it with real-time dynamic data to determine changes. Specifically, in the initial tunneling section where the geological conditions are relatively uniform and stable, the system automatically collects data on various parameters and calculates the average value and standard deviation of each ring index within this stage, which serve as the initial geological unit baseline.

[0045] During subsequent tunneling, the system compares the index values ​​calculated for the current ring with the currently effective baseline. If the index of the current ring not only exceeds the baseline but also reaches the pre-set absolute value threshold (such as "penetration mutation rate > 30%" or "torque fluctuation coefficient > 0.4"), or if multiple consecutive rings (such as 3 rings) trigger an early warning, the system determines that a significant adverse change has occurred in the strata and enters S1.2 to conduct advanced geological drilling for verification.

[0046] S1.2 When the tunneling parameters in step S1.1 show a continuous abnormal warning, use an advanced geological drilling rig positioned at the front of the shield or behind the cutterhead of the dual-shield TBM to drill 1-2 exploratory holes in front of the tunnel face. By recording the drilling process and identifying rock cores and cuttings samples, the soil conditions are analyzed to determine whether grouting reinforcement is necessary. Specific parameter indicators are as follows:

[0047] Rock Quality Index (RQD): The core samples are statistically analyzed. When the RQD value is below 25%, the rock mass is considered to be extremely fragmented, with very poor self-stabilizing ability and a risk of collapse.

[0048] Abnormal drilling speed and return water: In the expected hard rock strata, a sudden and abnormal increase in drilling speed, accompanied by the disappearance of borehole return water, a sharp decrease in water volume, or the return water becoming turbid, is a typical sign of revealing fault fracture zones, karst caves, or water-rich cavities.

[0049] Borehole water inflow: The water output per unit length of the exploration borehole is a key quantitative indicator; if the water inflow rate is consistently greater than 10 liters / minute, a water-rich area is confirmed, and the potential risks of water inflow and mud inflow must be assessed.

[0050] When any of the above indicators, especially the core direct detection indicators (such as RQD < 25% or confirmed water-rich fractured zone) or multiple tunneling parameter indicators, simultaneously reach the red action threshold, the system will trigger an early warning, determining that the surrounding rock cannot remain self-stable after tunneling, and the advanced grouting reinforcement procedure must be started immediately.

[0051] S2. Determination of grouting point coordinates

[0052] like Figure 2 As shown, a three-dimensional coordinate system is constructed with the center of the tunnel boring machine face as the origin, and the tunneling direction of the tunnel boring machine is taken as the +y axis. Then, the left side of the tunnel boring machine is the -x axis, the right side is the +x axis, the top of the tunnel boring machine is the +z axis, and the bottom of the tunnel boring machine is the -z axis.

[0053] To account for the grout diffusion radius, the reinforcement starting point is extended forward along the +y axis by a distance of 1.5 times the grout diffusion radius. Calculated with a diffusion radius of 1.5 meters, the reinforcement starting point should be located at 2.25 meters along the +y axis; therefore, the coordinates of the center point of the initial reinforcement surface are (0, 2.25, 0).

[0054] The number and coordinates of grout injection points are determined based on the tunnel boring machine (TBM) diameter and the grout diffusion area. Let the TBM radius be D, and the grout diffusion radius at a single point be R. To ensure reinforcement effectiveness, a 1 / 3 safety margin is maintained between adjacent grout injection points.

[0055] like Figure 2 As shown, the formula for calculating the distance from the grout injection point along the X and Z axes from the center point of the initial reinforced surface is: Subsequently, the coordinates of the grouting points at the four corners of the initial reinforced surface are respectively the upper right corner... Top left corner Bottom left corner bottom right corner ;

[0056] Then, the number of grouting points needs to be determined based on the tunnel boring machine radius D and the single-point grout diffusion radius R. The distance between adjacent corners can be determined based on the coordinates of the grouting points at the four corners of the initial reinforced surface. Furthermore, since the diffusion radius of the slurry at a single point is R and a safety margin of 1 / 3 is required, This indicates the distance from the outer edge of the tunnel boring machine to the edge of the grouting point.

[0057] To ensure the integrity and continuity of the grouting reinforcement, the grout diffusion range must effectively overlap between adjacent grouting points. The distance between adjacent points is set to a value equal to the grout diffusion diameter. That is, the distance between adjacent points ;

[0058] The steps for determining the number of grouting points are as follows:

[0059] First, calculate the number of points to be arranged in each direction (X-axis or Z-axis). Arrange grouting points along one side (length L) of the reinforced area, with the first and last points located at both ends, and the middle points evenly distributed at intervals d. The formula for calculating the number of points n is: In the formula This indicates rounding down to the nearest integer, ensuring the spacing is no greater than d;

[0060] Considering the actual arrangement as a grid, it is then arranged along the X-axis on the initial reinforced surface. Columns are arranged along the Z-axis. Okay, form The grouting point matrix. It is usually arranged symmetrically, i.e. .

[0061] Finally, calculate the total number of grouting points, i.e., the total number of points. .

[0062] Example calculation:

[0063] Assuming D = 3.0 m and R = 1.5 m, then: ; ; Therefore, the grouting points are arranged in a 5×5 grid, with a total of 25 points.

[0064] Based on the determined number of grouting points and the coordinates of the four corner grouting points on the initial reinforced surface, the coordinates of all grouting points on all initial reinforced surfaces are determined. The reinforced surface as a whole is a rectangular frame, and grouting points are evenly distributed along the X and Z axes at intervals d, forming an n×n grid. Then:

[0065] X-axis coordinate sequence: , ;

[0066] Z-axis coordinate sequence: , ;

[0067] The coordinates of all grouting points, and the coordinates of the grouting point in the i-th row and j-th column are: ;

[0068] in: The corresponding bottom row (with the smallest Z-coordinate). Corresponding to the leftmost column (with the smallest X-coordinate);

[0069] Example calculation

[0070] Assuming D = 3.0 m and R = 1.5 m, then , , , ;

[0071] X, Z coordinate sequence: −4.0, −2.0, 0, 2.0, 4.0

[0072] Coordinates of all 25 grouting points: bottom left corner Center point Top right corner .

[0073] S3. Determination of the number, location, and depth of wells.

[0074] The number of wells drilled is determined based on the value of the number of X-axis points, n. When D = 3.0 m and R = 1.5 m, it can be calculated that... Therefore, it can be determined that the number of wells to be drilled is 5;

[0075] Drilling is a downward drilling process from the ground. Therefore, the first step is to determine the relative position of the tunnel boring machine (TBM) on the ground, namely, the projection point A of the center point of the tunnel face on the ground and the projection point B of the center point of the tail end of the TBM on the ground. The location of the projection point can be found using the TBM's shield guidance system, which provides its three-dimensional coordinates, attitude, and tunneling mileage in real time. By using methods such as gyro orientation, precision traverse surveying, or vertical shaft projection, the construction coordinate system of the underground tunnel can be accurately converted and unified with the ground city coordinate system or the engineering independent coordinate system. Similarly, the distance H from the center point of the tunnel face to the projection point A can be determined.

[0076] Once the positions of points A and B are determined, a line segment is constructed between points A and B. With point A as the center point, a line segment Q is constructed perpendicular to line segment AB. This line segment Q is a line parallel to the ground surface of the tunnel boring machine face. Then, an extension line perpendicular to line segment Q is drawn in the opposite direction from point A to point B. Subsequently, the initial reinforcement surface and the subsequent reinforcement surfaces are all perpendicular to this extension line.

[0077] The ground projection parallel line of the grouting reinforcement surface is determined. The position of the ground parallel line segment Q of the tunnel boring machine face has already been determined. Since the initial reinforcement surface is located at 2.25 meters along the +y axis, the ground projection parallel line of the initial reinforcement surface is perpendicular to the extension line and 2.25 meters away from line segment Q. Then, based on the X-axis coordinate sequence in step S2... , This allows us to determine the location of each shaft on the initial reinforcement surface.

[0078] Taking D=3.0 m and R=1.5 m as an example, the X coordinate sequence calculated in step S2 is −4.0, −2.0, 0, 2.0, 4.0, which determines that the number of wells allowed is 5, and the middle well point is exactly located on the extension line. Then, the middle well point C1 is located on the extension line at a distance of 2.25 meters from point A. With point C1 as the center point, a line segment C perpendicular to the extension line is constructed. Then, based on the X coordinate sequence, the positions of C2 to C5 can be determined. C2 is located on line segment C 2 meters below point C1, C3 is located on line segment C 4 meters below point C1, C4 is located on line segment C 2 meters above point C1, and C5 is located on line segment C 4 meters above point C1.

[0079] Once the drilling locations of C1~C5 are determined, the drilling depth can be determined, such as... Figure 5 As shown, the distance from the center point of the working face to the lowest grouting point is... The distance from the center point of the drilling face to the projection point A is H, and the drilling depth is... ;

[0080] Once the number, location, and depth of wells are determined, drilling can begin. The well diameter can be uniformly set at 30cm. Two to three drilling rigs should be organized to work simultaneously, following the sequence of "outer perimeter first, then inner perimeter, with intermittent skip drilling" to reduce mutual interference between adjacent boreholes.

[0081] S4. Catheter preparation

[0082] Since the conduit is buried in the ground and will not be retrieved later, a PE pipe with an outer diameter of 110mm and an inner diameter of 101.6mm can be selected. Prepare a conduit of appropriate length according to the drilling depth determined in S3. The drilling depth is... In other words, the catheter length can be selected. +0.2 meters, where 0.2 meters is the length left on the ground for connecting to the grouting equipment.

[0083] After cutting the appropriate length of the guide pipe, seal the end buried underground, and then open the grouting holes. It is necessary to first determine the number of double-hole guide pipes and full-hole guide pipes. The so-called double-hole guide pipes are the guide pipes for the wells in the middle of the shield machine, while the full-hole guide pipes are the guide pipes for the wells on both sides of the shield machine. Only two of them are needed, and the rest are double-hole guide pipes. The combination of double-hole guide pipes and full-hole guide pipes is to establish a grouting reinforcement matrix underground. However, it is necessary to avoid not grouting reinforcement in the direction of shield machine excavation, so as to avoid cement slurry reinforcement during the excavation process, which would increase the difficulty of excavation.

[0084] For the grouting holes of the full-bore guide pipe, the location of the sealing end of the guide pipe, i.e., the lowest grouting point, is used as the starting point to mark the positions of each grouting point. The positions of the grouting points are based on the Z-axis coordinate sequence in step S2. , For example, with D=3.0 m and R=1.5 m, the Z coordinate sequence is −4.0, −2.0, 0, 2.0, 4.0. The spacing between each grouting point is calculated to be 2 meters. Therefore, starting from the bottom grouting point, the points are marked sequentially at 2-meter intervals upwards. There are a total of 5 Z coordinate sequences, so 5 marks are sufficient.

[0085] In addition, the coordinates of the distance between the lowest grouting point and the highest grouting point are (−4.0, 4.0), which is 8 meters. Then, based on the position of the sealing end of the guide pipe, i.e. the position of the lowest grouting point, the position of the highest grouting point can be marked by moving upwards at a distance of 8 meters from this position.

[0086] After the grouting point locations are marked, the drilling section needs to be determined. The length of the drilling section is uniformly set to 20cm. For the drilling section at the lowest grouting point of each guide pipe, the drilling section is marked 20cm upwards from the grouting point as the starting point. For the drilling sections at other grouting points, the drilling section is marked 10cm above and below the grouting point as the midpoint, with a total length of 20cm.

[0087] After marking, drilling work begins. The drilling section is 20cm long, with each layer spaced 5cm apart. There are a total of 5 drilling layers from the beginning to the end of the section. Each layer of drilling uses a through-hole method and is drilled twice. Each layer has 4 grout outlet holes. There are 20 grouting holes at one grouting point. The positions of the upper and lower layers of drilling are offset by 60° from each other, forming a spiral drilling matrix. A drill bit with a cutting diameter of 20mm is selected for drilling.

[0088] Once drilling is complete, the guide pipe can be placed inside the well. Note the distinction between double-hole guide pipes and full-hole guide pipes. Full-hole guide pipes are drilled on both sides of the well, while double-hole guide pipes are drilled in the middle.

[0089] S5, Drilling Backfill

[0090] Backfilling of the well is achieved through alternating filling with stones and concrete. This is to prevent the borehole from being blocked by backfill material and to prevent grout from gushing out of the well during grouting. Based on the 20cm length of the borehole section, the height of the stone filling layer can be set at 40cm, with an additional 10cm extending above and below the borehole section as a buffer. The spaces between each stone filling layer and between the top stone filling layer and the ground surface are filled with concrete. Note that the concrete should not be vibrated here to prevent cement from flowing into the stone filling layer and causing blockage of subsequent grout filling.

[0091] Taking D=3.0 m and R=1.5 m as an example, the Z-coordinate sequence is −4.0, −2.0, 0, 2.0, 4.0, and the drilling depth is... In other words, the catheter length can be selected. +0.2 meters, assuming H=20, the drilling depth is 24m, and based on the setting of a 40cm height for the rock filling layer,

[0092] The filling sequence and height of the drill rock filling layer and the concrete filling layer on both sides are as follows:

[0093] A 0.3m stone filling layer, a 1.5m concrete filling layer, a 0.4m stone filling layer, a 1.6m concrete filling layer, a 0.4m stone filling layer, a 1.6m concrete filling layer, a 0.4m stone filling layer, a 1.6m concrete filling layer, a 0.4m stone filling layer, a 15.8m concrete filling layer, are used to form a 24m filling section.

[0094] The initial 0.3m stone filling layer and the initial 1.3m concrete filling layer are because the drilling section at the lowest grouting point of each guide pipe is marked 20cm upwards from the grouting point as the starting point of the drilling section. Therefore, the initial stone filling layer is a buffer of 10cm upwards from the length of the drilling section, which is the 0.3m stone filling layer. The second stone filling layer is filled with 0.2m lengths above and below the grouting point, with a total length of 0.4m. Therefore, the distance between the second and the initial stone filling layer is a 1.5m concrete filling layer.

[0095] The filling sequence and height of the intermediate drill rock filling layer and concrete filling layer are as follows:

[0096] 0.3m stone filling layer, 7.5m concrete filling layer, 0.4m stone filling layer, 1.6m concrete filling layer;

[0097] The 7.5m concrete filling layer is to prevent the grout from reinforcing the tunnel boring machine's excavation area, which would increase the difficulty of excavation.

[0098] During the filling process, a plumb bob measuring rope is used to measure the current material surface elevation. According to the calculated filling sequence and height of the stone filling layer and concrete filling layer, a mark is set at the corresponding position on the measuring rope. After each part of the material is put in, the pre-marked measuring rope is lowered to the current material surface. By observing the relationship between the pre-marked design depth mark on the measuring rope and the fixed reference point at the wellhead, it is then determined whether the current material surface has reached the target depth.

[0099] S6. Grouting: Grouting operations are divided into two stages: preparation and implementation.

[0100] Grouting preparation:

[0101] Based on geological forecasts and exploration results, select a suitable grout type (such as cement grout, cement-water glass two-component grout, etc.) and determine the grout mix ratio, initial setting time and final setting time.

[0102] Connect the ground grouting equipment to the exposed end of the conduit and conduct a pipeline airtightness and unobstructedness test.

[0103] Set the upper limit of grouting pressure (usually 1.5 to 2.0 times the formation hydrostatic pressure) and the control value of grouting volume per hole.

[0104] Grouting implementation:

[0105] The grouting sequence is segmented, spaced, and skip-hole, first grouting the outer holes (full-hole guide pipe), then grouting the inner holes (double-hole guide pipe) to form a closed reinforcement ring from the outside to the inside.

[0106] When grouting a single hole, the principle of "low pressure and slow injection, gradually increasing pressure" should be followed, and the grouting pressure and flow rate should be monitored in real time.

[0107] When the grouting pressure reaches the design limit and continues to rise, stop grouting in that hole.

[0108] This completes the grouting work for the initial reinforcement surface.

[0109] S7. Stepping: The stepping process involves the continuous execution of reinforcement work, and it is necessary to monitor the geological conditions in real time during subsequent work to determine whether further reinforcement is needed.

[0110] Step S6 completes the initial grouting reinforcement of the surface. Then, the location of subsequent reinforcement surfaces needs to be determined based on the grout diffusion radius. Figure 4 As shown, the initial reinforcement surface and the working face are 2.25m apart, including the slurry diffusion radius and a reserved distance of 1.5 times the slurry diffusion radius;

[0111] The distance T between the second reinforced surface and the initial reinforced surface is the distance between the two slurry diffusion radii minus 1 / 3 of the safety margin. The formula for calculating the distance is as follows: Taking R=1.5 m as an example, the distance between the second reinforced surface and the initial reinforced surface is... Therefore, the coordinates of the center point of the second reinforced surface on the Y-axis can be obtained as (0, ). +2.25, 0) is equivalent to (0, 4.75, 0);

[0112] Based on this, the coordinates of the center point of the subsequent reinforcement surface on the Y-axis (0, ) can be calculated. +2.25, 0) ; For the third reinforcement surface, This is the fourth reinforced surface, and so on. For the first Reinforced surface;

[0113] Once the position of the reinforced surface on the Y-axis is determined, the coordinates of each grouting point on the reinforced surface can be determined according to step S2. Steps 3 to 6 are repeated to carry out drilling, guide pipe installation, backfilling and grouting work, and so on to complete all grouting work.

[0114] In subsequent drilling operations, similar to step S1.2, the drilling process is recorded and core and slag samples are identified to analyze the soil conditions and determine whether grouting reinforcement is required. If no grouting reinforcement is required, the reinforcement work of the current warning section is completed, and tunneling can proceed until the next TBM tunneling parameter warning occurs in step S1.1.

[0115] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention 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. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for grouting reinforcement using a double-shield TBM with advanced small-diameter guide pipes, characterized in that, The method includes the following steps: S1. Based on real-time monitoring of TBM tunneling parameters and advanced geological drilling, determine whether the strata ahead need grouting reinforcement. S2. Establish a coordinate system with the center of the tunnel boring machine face as the base point. Calculate the three-dimensional coordinates of each grouting point on the initial reinforcement surface and the total number of grouting points based on the radius of the tunnel boring machine and the grout diffusion radius. S3. Based on the grouting point coordinates determined in S2, determine the number and location of wells by constructing a ground projection, and calculate the drilling depth by using the distance H between the center point of the working face and the projection point A. S4. Prepare a guide pipe that matches the drilling depth, and open grouting holes on the guide pipe at the grouting point coordinates determined in S2. The guide pipes located on both sides of the tunnel are full-hole guide pipes with all grouting holes, and the rest are double-hole guide pipes with some grouting holes. S5. After the guide pipe is inserted into the well, the stone filling and concrete filling are alternately filled. The uppermost stone filling layer is filled with concrete filling layer between it and the ground. The stone filling layer extends into the borehole section with buffer sections above and below. S6. Inject grout into the formation through the conduit. Stop when the grouting pressure reaches the design upper limit and continues to rise. S7. Calculate the distance between the second reinforced surface and the initial reinforced surface based on the slurry diffusion radius R. Then, determine the coordinates of the center point of the subsequent reinforcement surface on the Y-axis, repeat step S2 to determine the coordinates of each grouting point on each reinforcement surface, and repeat steps 3 to 6 to carry out drilling, guide pipe installation, backfilling and grouting work.

2. The method for grouting reinforcement using a double-shield TBM with advanced small guide pipes as described in claim 1, characterized in that, In step S2, the coordinates of each grouting point are determined by first constructing a three-dimensional coordinate system with the center of the tunnel face of the shield machine as the origin. The coordinate system is based on the tunneling direction of the shield machine as the +y axis. The coordinates of the center point of the initial reinforced surface are obtained by extending the +y axis forward by 1.5 times the grout diffusion radius from the starting position of the grouting reinforcement.

3. The method for grouting reinforcement using a double-shield TBM with advanced small guide pipes as described in claim 1, characterized in that, In step S2, the distances of the grout injection points on the X and Z axes from the center point of the initial reinforced surface are obtained based on the coordinates of the center point of the reinforced surface, the radius D of the tunnel boring machine, and the single-point grout diffusion radius R. Then, the coordinates of the grout injection points at the four corners of the initial reinforced surface are determined.

4. The construction method for double-shield TBM advanced small-diameter pipe grouting reinforcement as described in claim 1, characterized in that, In step S2, the distance L between adjacent angles and the spacing between adjacent points are obtained based on the shield machine radius D and the single-point slurry diffusion radius R. The diameter of the slurry diffusion Then, through the distance L between adjacent corners and the spacing between adjacent points Count the points on one side of the matrix That is, the total number of points in the grouting point matrix. Since the grouting points are evenly arranged along the X and Z axes at intervals d, forming an n×n rectangular frame grid, the coordinates of all grouting points on all initial reinforcement surfaces are determined by the number of grouting points and the coordinates of the grouting points at the four corners of the initial reinforcement surface.

5. The construction method for double-shield TBM advanced small-diameter pipe grouting reinforcement as described in claim 1, characterized in that, In step S4, the length of the guide pipe is calculated based on the distance H from the center point of the tunnel face to the projection point A, the radius D of the tunnel boring machine, and the single-point slurry diffusion radius R. At the same time, the grouting point position is marked on the guide pipe according to the Z-axis coordinate sequence in step S2. The drilling section is marked with the grouting point base point. The drilling is carried out in layers at fixed intervals, and the positions of the upper and lower layers of drilling are set with a fixed deviation angle.

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