Intelligent and automatic grouting method suitable for soft and broken roof of deep buried highway tunnel

Abstract

This invention discloses an intelligent automated grouting method suitable for weak and fractured roof slabs in deeply buried highway tunnels, comprising the following steps: (1) During the excavation of the highway tunnel, a grouting main pipe system is deployed along the entire length of its sidewalls; (2) During the advancement of the tunnel face, hollow grouting anchor cables are installed in the weak and fractured roof slabs of the highway tunnel at a distance of 10-20m from the tunnel face, and the hollow grouting anchor cables are connected to the grouting main pipe for grouting; (3) During the advancement of the tunnel face, a monitoring and early warning instrument is quickly deployed in the weak and fractured roof slabs of the tunnel lagging behind the tunnel face; (4) When the grouting main pipe system receives an early warning signal, the weak and fractured roof slabs of the highway tunnel are automatically grouted. This invention can monitor the delamination amount of the weak and fractured roof slabs in real time, accurately grasp the grouting timing, ensure the grouting effect, significantly reduce the tedious and repetitive work of manual grouting, avoid incorrect judgment of the grouting timing, and improve the grouting efficiency of the weak and fractured roof slabs of highway tunnels.

Description

Technical Field

[0001] This invention belongs to the field of tunnel engineering, and in particular relates to an intelligent automated grouting method suitable for the weak and broken roof slab of deeply buried highway tunnels. Background Technology

[0002] In the field engineering practice of deep-buried highway tunnels, it has been found that after strong excavation disturbance, the internal cracks of weak and fractured roof slabs supported by high-strength materials develop and break down, leading to phenomena such as loosening and failure of the support structure, and even roof collapse. At the construction site, grouting was attempted to reinforce the disturbed cracks in the weak and fractured roof slabs of deep-buried highway tunnels. However, determining the optimal grouting time is difficult because the cracks in the weak and fractured roof slabs are at different stages of deformation and fracture development at different times and in different areas. If grouting is done too early, the crack opening in the roof slab is small, making it difficult to inject grout, resulting in poor grouting effect. Furthermore, strong disturbance may cause further damage to the grout-reinforced rock mass, leading to grouting reinforcement failure. If grouting is done too late, the roof slab is severely deformed and has lost its bearing capacity. Although the crack opening in the roof slab is large, making grout injection easier, the roof slab and the primary support structure have already become unstable and damaged. At this point, grouting is meaningless, meaning the optimal grouting time has been missed. Grouting the roof too early or too late can result in poor grouting effects on weak and fractured roofs, making it difficult to form a complete load-bearing structure. This invention provides an intelligent automated grouting method suitable for weak and fractured roofs in deeply buried highway tunnels. It not only determines the correct grouting timing but also achieves automated grouting, aiming to improve the grouting effect on mining-induced fractures in weak and fractured roofs, ensuring the formation of a complete load-bearing structure and protecting the integrity, stability, and safety of the surrounding rock in deeply buried highway tunnels. Summary of the Invention

[0003] The purpose of this invention is to solve the above-mentioned problems and provide an intelligent automated grouting method suitable for weak and fractured roof slabs in deeply buried highway tunnels. This method is used for intelligent automated grouting of weak and fractured roof slabs during highway tunnel excavation, or for intelligent automated grouting of the weak and fractured roof slab of Highway Tunnel No. 2 when excavating another highway tunnel (Highway Tunnel No. 2) next to a completed highway tunnel (Highway Tunnel No. 1) (the wall between the two tunnels is a concrete wall). The aim is to improve the grouting effect on weak and fractured roof slabs in deeply buried highway tunnels, ensure that the roof slab forms a complete load-bearing structure, and guarantee the integrity, stability, and safety of the surrounding rock of the highway tunnel.

[0004] This invention is achieved through the following technical solution:

[0005] An intelligent and automated grouting method applicable to the weak and fractured roof slab of deeply buried highway tunnels involves preparing for grouting of the weak and fractured roof slab during the tunnel excavation and support process. This method includes the following steps:

[0006] As the tunnel face advances, a grouting main system is deployed along the entire length of the tunnel face. This system includes a grouting main pipe and a grouting pump connected to it. The main pipe also has several grouting main pipe connectors with intelligent control valves for branch grouting. First, a grouting pump station is set up in the tunnel face to house the multi-functional grouting pump and grouting materials. Then, along the tunnel axis, the grouting main pipe is fixed in the upper middle part of the tunnel face, extending its entire length, and one end is connected to the multi-functional grouting pump.

[0007] The main grouting pipe is made of steel or plastic round pipe, with an internal partition dividing it into two grouting channels: Grouting Channel A and Grouting Channel B. Every 2-3 meters along the main grouting pipe, there is a pair of grouting pipe connectors, each equipped with an intelligent control valve. These connectors are used to connect to branch grouting pipes in the weak and fractured roof slab; one connects to Grouting Channel A, and the other to Grouting Channel B. The intelligent control valves are both closed when grouting is not in progress. Preferably, the main grouting pipe has a diameter of 50-80 mm and consists of several sections, each 2-3 meters long. A pair of grouting pipe connectors, each with an intelligent control valve, is located in the middle of each section.

[0008] Each section of the grouting main pipe has an internal thread section and an external thread section at both ends, and the two sections of the grouting main pipe are connected and fixed by the threaded section. After connection, the channels of grouting main pipe A and B are connected. The purpose of designing the grouting main pipe with two grouting channels A and B is to meet both single-liquid grouting and double-liquid grouting requirements, and to accommodate a wide variety of grouting materials to meet various grouting requirements.

[0009] Two-liquid grouting involves injecting two different grouts into the grout mixing section through two grouting pressurization units and two grouting pipes. After being mixed evenly, the mixture is injected into the target rock mass fissures.

[0010] Single-liquid grouting involves injecting a single grout (with the addition of different additives) into the target rock mass fissures through a grouting pressurization unit and a grouting pipe.

[0011] During tunnel face advancement, several hollow grouting anchor cables are installed as branch grouting pipes within 10-20m of the weak and fractured roof. These hollow grouting anchor cables are connected to the main grouting pipe for grouting. Generally, the width of a highway tunnel is greater than 9m. The arrangement parameters for the hollow grouting anchor cables in the weak and fractured roof are as follows: the hollow grouting anchor cable boreholes are located in the middle of the weak and fractured roof, with at least one borehole per row. All the hollow grouting anchor cable inlets in each row converge and correspond to a grouting main pipe joint, or each hollow grouting anchor cable corresponds to a corresponding number of grouting main pipe joints. The borehole diameter is 32-48mm, the borehole spacing is 2-3m, and the borehole depth is... LThe thickness is determined based on 1.2 times the thickness of the weak and fractured roof slab. Preferably, when there is already a highway tunnel next to the one under construction, the borehole is set vertically upward or inclined at 10-30° towards the side wall of the adjacent non-concrete wall; when there is no other highway tunnel next to the one under construction, the middle borehole is set vertically upward, and the boreholes on both sides are inclined at 10-30° towards the side walls on both sides respectively.

[0012] Hollow grouting anchors are chosen because they allow for grouting while simultaneously enhancing the support strength of weak and fractured roof slabs. Hollow grouting anchor parameters: diameter 22–32 mm, hollow grouting pipe diameter 12 mm, anchor length… l =Drilling depth L +300mm. Construction steps: First, use a ZQJJ120 / 2.3 column-supported drilling rig to drill holes. After each grouting drill is completed, immediately install one hollow grouting anchor cable. Then, fit a 350mm long sealing device onto the tail of the hollow grouting anchor cable and embed it 400mm into the drill hole to seal the borehole opening and prevent grout leakage. Finally, connect the hollow grouting anchor cable and the main grouting pipe through a Y-shaped rubber grouting pipe to achieve grouting. The bifurcated hose at one end of the Y-shaped rubber grouting pipe is connected to the intelligent control valve of the main grouting pipe joint on grouting channel A and the intelligent control valve of the main grouting pipe joint on grouting channel B, respectively. The other end is connected to the grouting pipe joint located at the tail of the hollow grouting anchor cable. The Y-shaped rubber grouting pipe is fixed tightly against the surrounding rock. Specifically, all the grouting pipe joints at the tail of the hollow grouting anchor cables in each row of drill holes are collected together through pipes to correspond to one Y-shaped rubber grouting pipe.

[0013] The function of the Y-type rubber grouting pipe: During dual-liquid grouting, two different grouts enter the grout mixing section through the Y-type rubber grouting pipe, are mixed evenly, and then injected into the target rock mass fissures.

[0014] As the tunnel face advances, roof monitoring and early warning instruments are rapidly deployed within the weak and fractured roof slab of the lagging tunnel face to measure the amount of delamination and subsidence at both deep and shallow locations within the weak and fractured roof slab, thereby determining the timing for grouting. Preferably, as the tunnel face advances, roof monitoring and early warning instruments are rapidly deployed within the tunnel every 5-15m, more preferably every 10m, with the monitoring station 2m away from the concrete wall and a station spacing of 10m. The purpose is to measure the amount of delamination and subsidence at both deep and shallow locations within the weak and fractured roof slab, thereby determining the timing for grouting.

[0015] As a preferred option, the YHW150 roof monitoring and early warning instrument was selected. The YHW150 roof monitoring and early warning instrument is an intelligent instrument used to monitor tunnel roof settlement and crack development, and it has monitoring and early warning functions. This early warning instrument includes three sets of pawls and measuring ropes, and one digital display early warning device. The pawls and measuring ropes are disposable, while the digital display early warning device is reusable.

[0016] Installation steps for the roof monitoring and early warning device: ① Drill one hole vertically in the middle of the weak and fractured roof of the highway tunnel. The hole diameter is 30mm, and the drilling depth is determined based on 1.2 times the thickness of the weak and fractured roof. ② Install pawls for deep, medium-deep, and shallow foundation points sequentially inside the hole. Use the installation rod to move the pawls to the designed position, tightening the measuring rope during insertion. ③ Connect the exposed measuring rope at the borehole opening to the digital display early warning device to complete the installation. ④ The user sets the delamination amount and delamination speed early warning thresholds for the weak and fractured roof of the highway tunnel. When the thresholds are reached, the early warning device automatically issues an early warning. The early warning signal emitted by each roof monitoring and early warning device can be received by 3-6 pairs of nearby intelligent control valves, preferably 5 pairs.

[0017] The warning threshold of the roof monitoring and early warning instrument is set to two types: ① When the total amount of roof delamination is 150-200mm and the delamination speed is less than 2mm / d, an alarm is triggered; ② When the total amount of roof delamination is greater than 200mm, an alarm is triggered.

[0018] During highway tunnel construction, the grouting pump is in standby mode. When the intelligent control valve on the main grouting pipe receives a warning signal, it automatically opens immediately. The grouting fluid sequentially flows through the grouting pump, the main grouting pipe, the Y-shaped rubber grouting pipe, and the grouting pipe of the hollow grouting anchor cable into the weak and fractured rock mass of the roof. When the grouting time or grouting volume reaches the set value, the intelligent control valve closes, stopping the grouting, indicating that the grouting of the weak and fractured roof of one section of the highway tunnel is complete.

[0019] Preferably, the grouting material for the weak and fractured roof is Marisan, which has the characteristics of low viscosity, good adhesion, excellent compressive strength, high expansion rate, and strong flexibility. Marisan and the catalyst liquid solidify 1.5–3 hours after injection into the rock fractures. Grouting parameters: The volume ratio of Marisan resin to catalyst is 1:1, and the weight ratio is 1:1.17. The grouting time is determined according to the grouting requirements of the weak and fractured roof.

[0020] Maresan is a two-component grouting material. The grouting process is as follows: After the multi-functional grouting pump and its accessories are assembled, two suction pipes are inserted into the tank containing Maresan resin and catalyst. The multi-functional grouting pump is started, and the Maresan resin enters the main grouting channel A, while the catalyst enters the main grouting channel B. During the tunnel face advancement, when the delamination of the weak and fractured roof slab in the highway tunnel gradually increases and reaches the set delamination value, the roof delamination instrument issues an early warning. Five nearby intelligent control valves receive the warning signal from the delamination instrument and automatically open the intelligent control valves, allowing the grout to enter the grouting pipe of the weak and fractured roof slab through the Y-shaped rubber hose. After the set grouting time is reached, the multi-functional grouting pump stops grouting. The Y-shaped rubber hose is removed, cleaned with a cleaning agent, and can be reused.

[0021] (5) Dismantle the grouting pipeline equipment

[0022] Once the grouting of the weak and fractured roof slab of a section of the highway tunnel is completed and has solidified, the disposable Y-shaped rubber hose and the reusable digital display early warning device can be removed. After the entire highway tunnel construction is completed, the main grouting pipe is flushed and all pipelines are removed for reuse.

[0023] The beneficial effects of this invention are:

[0024] Compared with existing technologies, the intelligent automated grouting method of the present invention, applicable to the weak and fractured roof slab of deeply buried highway tunnels, has the following advantages:

[0025] (1) During the construction of deep-buried highway tunnels, the amount of delamination of the weak and fractured roof slab is monitored in real time. When the amount of delamination reaches the set warning value, grouting is carried out in a timely manner to fill the mining-induced cracks in the weak and fractured roof slab, effectively ensuring the effective filling of different cracks and cavities. This innovative intelligent grouting method can accurately grasp the grouting opportunity in a timely manner, ensuring the grouting effect of the weak and fractured roof slab, improving the stability and safety of the weak and fractured roof slab, and realizing the scientific control of grouting reinforcement of mining-induced cracks in the weak and fractured roof slab of deep-buried highway tunnels.

[0026] (2) In highway tunnels, grouting pipelines are laid out along the entire line and intelligent automatic grouting is carried out, which significantly reduces the tedious and repetitive work of manual grouting, avoids the wrong judgment of grouting timing, improves the grouting efficiency of the roof of deeply buried highway tunnels, has a wider range of applications, is more practical, and is worth promoting. Attached Figure Description

[0027] For ease of explanation, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0028] Figure 1 This is a structural schematic diagram of the highway tunnel layout and grouting equipment arrangement in an embodiment of the present invention;

[0029] Figure 2 for Figure 1 The cross-sectional view along the central axis (II) shows a schematic diagram of the hollow grouting anchor cable arrangement structure for the weak and fractured roof slab of the highway tunnel.

[0030] Figure 3 yes Figure 1 The cross-sectional view along the middle II-II direction shows a schematic diagram of the layout structure of the monitoring station for the delamination deformation of the weak and fractured roof slab in the highway tunnel.

[0031] Figure 4 This is a schematic diagram of the longitudinal structure of the grouting main pipe in an embodiment of the present invention;

[0032] Figure 5 yes Figure 4 Schematic diagram of the cross-sectional structure in the middle II direction.

[0033] Explanation of reference numerals in the attached diagrams: 1. Highway Tunnel No. 1; 2. Highway Tunnel No. 2; 3. Concrete wall; 4. Working face; 5. Connecting passage; 6. Main grouting pipe; 6-1. Grouting pipe A channel; 6-2. Intelligent control valve for grouting pipe A channel joint; 6-3. Grouting pipe B channel; 6-4. Intelligent control valve for grouting pipe B channel joint; 6-5. Grouting pipe partition; 7. Grouting pump station; 8. Side wall; 9. Y-type rubber grouting pipe; 10. Grouting borehole; 11. Soft and broken roof; 12. Hollow grouting anchor cable; 13. Roof delamination device; 13-1. Pawl; 13-2. Steel wire; 13-3. Digital display early warning device. Implementation

[0034] This intelligent automated grouting method is applicable to the weak and fractured roof slab of deeply buried highway tunnels. It is used for intelligent automated grouting of weak and fractured roof slabs during highway tunnel excavation, or for intelligent automated grouting of the weak and fractured roof slab of Highway Tunnel No. 2 when excavating another highway tunnel (Highway Tunnel No. 2) next to an already constructed highway tunnel (the wall between the two tunnels is a concrete wall). Because if there is already a highway tunnel nearby, the weak and fractured roof slab of the newly constructed tunnel will be more vulnerable and more easily damaged due to the increased disturbance. Therefore, this embodiment selects the support object when there is already a highway tunnel next to the newly constructed Highway Tunnel No. 2, that is, when Highway Tunnel No. 1 has already been constructed next to the newly constructed Highway Tunnel No. 2, the intelligent automated grouting method is applied to its weak and fractured roof slab.

[0035] like Figure 1-5 As shown in the figure, this embodiment describes an intelligent automated grouting method applicable to the weak and fractured roof slab of a deeply buried highway tunnel. According to the construction drawings, preparations for grouting the weak and fractured roof slab of the highway tunnel begin during the excavation and support of the No. 2 highway tunnel, as detailed below:

[0036] As the tunnel face 4 of Highway 2 advances, a grouting main pipe system is installed along the entire length of its sidewall 8. In this embodiment, the grouting main pipe system is installed within 20-30m of the tunnel face. First, a grouting pump station 7 is set up near the sidewall 8 of Highway 2 to house the multi-functional grouting pump and grouting materials. Then, along the axial direction of Highway 2, the grouting main pipe 6 is fixed in the upper middle part of the sidewall, extending its entire length, and one end of it is connected to the multi-functional grouting pump station 7.

[0037] The main grouting pipe 6 is made of steel or plastic round pipe with a diameter of 50-80mm and a length of 2-3m per section. A cross-section of the main grouting pipe 6 shows that an internal partition 6-5 divides the pipe into two grouting channels: grouting channel A 6-1 and grouting channel B 6-2. A pair of grouting pipe connectors, each equipped with an intelligent control valve, are located in the middle of each section. These connectors connect to branch grouting pipes on the roof slab. The upward-opening intelligent control valve 6-2 connects to grouting channel A 6-1, and the downward-opening intelligent control valve 6-4 connects to grouting channel B 6-3. Both valves are closed when not grouting. (See the structure of the main grouting pipe...) Figure 2 As shown.

[0038] Each section of the grouting main pipe has an internal thread section and an external thread section at both ends, and the two sections of the grouting main pipe are connected and fixed by the threaded section. After connection, the channels of grouting main pipe A and B are connected. The purpose of designing the grouting main pipe with two grouting channels A and B is to meet both single-liquid grouting and double-liquid grouting requirements, and to accommodate a wide variety of grouting materials to meet various grouting requirements.

[0039] Two-liquid grouting involves injecting two different grouts into the grout mixing section through two grouting pressurization units and two grouting pipes. After being mixed evenly, the mixture is injected into the target rock mass fissures.

[0040] Single-liquid grouting involves injecting a single grout (with the addition of different additives) into the target rock mass fissures through a grouting pressurization unit and a grouting pipe.

[0041] During the advancement of the tunnel face 4 of Highway 2, hollow grouting anchor cables 12 are installed in the weak and fractured roof slab 11 within 10-20m of the tunnel face 4. Each hollow grouting anchor cable 12 corresponds to a grouting main pipe joint in the sidewall. Generally, the width of a highway tunnel is greater than 9m. The arrangement parameters of the hollow grouting anchor cables 12 in the weak and fractured roof slab 11 are as follows: the hollow grouting anchor cable boreholes are located in the middle of the weak and fractured roof slab, with at least one borehole 10 arranged in each row. If multiple boreholes are included... Figure 1 Except for the central borehole shown, the adjacent boreholes are not shown. The grouting pipe inlets of all hollow grouting anchors within each row of boreholes converge via connecting pipes, corresponding to a grouting main pipe joint on a single grouting main pipe, or each hollow grouting anchor corresponds to a specific number of grouting main pipe joints. The borehole diameter is 32–48 mm, the borehole spacing is 2–3 m, and the borehole depth is… LThe thickness is determined based on 1.2 times the thickness of the weak and fractured roof slab 11. When there is already a highway tunnel next to it, such as when there is already a highway tunnel 1 next to highway tunnel 2 in this embodiment, the borehole is set vertically upward or inclined at 10-30° towards the side of the non-concrete wall next to it; when the highway tunnel is a new tunnel without other highway tunnels next to it, the borehole in the middle can be set vertically upward, and the boreholes on both sides can be inclined at 10-30° towards the side walls on both sides respectively.

[0042] Hollow grouting anchors are chosen because they allow for grouting while simultaneously enhancing the support strength of weak and fractured roof slabs. Hollow grouting anchor parameters: diameter 22–32 mm, hollow grouting pipe diameter 12 mm, anchor length… l =Drilling depth L +300mm. Construction steps: First, use a ZQJJ120 / 2.3 column-supported drilling rig to drill holes. After each grouting hole is completed, immediately install one hollow grouting anchor cable. Then, fit a 350mm long sealing device onto the tail of the hollow grouting anchor cable and embed it 400mm into the drill hole to seal the borehole opening and prevent grout leakage. Finally, connect the bifurcated hose at one end of the Y-type rubber grouting pipe 9 to the intelligent control valve 6-2 of the grouting main A channel connector and the intelligent control valve 6-4 of the grouting main B channel connector, and connect the other end to the grouting pipe connector at the tail of the anchor cable. The Y-type rubber grouting pipe is fixed tightly against the surrounding rock.

[0043] The function of the Y-type rubber grouting pipe: During dual-liquid grouting, two different grouts enter the grout mixing section through the Y-type rubber grouting pipe, are mixed evenly, and then injected into the target rock mass fissures.

[0044] As the tunnel face 4 advances, every 10m of the highway tunnel is completed, a roof monitoring and early warning instrument 13 is quickly deployed inside the highway tunnel. The measuring station is 32m away from the concrete wall and the station spacing is 10m. The purpose is to measure the amount of delamination and subsidence in the deep and shallow parts of the weak and broken roof slab 11, so as to determine the timing of grouting.

[0045] In this embodiment, the YHW150 roof monitoring and early warning device is selected for monitoring. The early warning device includes three sets of pawls 13-1, measuring ropes 13-2, and one digital display early warning device 13-3. The pawls and measuring ropes are disposable products, while the digital display early warning device can be reused.

[0046] Installation steps for Roof Monitoring and Early Warning Device 13: ① Drill one hole vertically in the middle of the weak and fractured roof slab of the highway tunnel. The hole diameter is 30mm, and the drilling depth is determined based on 1.2 times the thickness of the weak and fractured roof slab. ② Install pawls for deep, medium-deep, and shallow foundation points sequentially inside the hole. Use the installation rod to move the pawls to the designed position, tightening the measuring rope during insertion. ③ Connect the exposed measuring rope at the borehole opening to the digital display early warning device to complete the installation. ④ The user sets the delamination amount and delamination speed early warning thresholds for the weak and fractured roof slab of the highway tunnel. When the thresholds are reached, the early warning device automatically issues an early warning. The early warning signal emitted by each roof monitoring and early warning device can be received by five pairs of nearby intelligent control valves.

[0047] The warning threshold of the roof monitoring and early warning instrument is set to two types: ① When the total amount of roof delamination is 150-200mm and the delamination speed is less than 2mm / d, an alarm is triggered; ② When the total amount of roof delamination is greater than 200mm, an alarm is triggered.

[0048] A roof delamination meter is a specialized monitoring instrument for monitoring the movement of roof strata. The roof delamination meter 13 consists of a pawl 13-1, a steel wire 13-2, and a digital display early warning device 13-3. The digital display early warning device itself is common in this field. Working principle: In commonly used roof delamination meters, the pawl is connected to the digital display early warning device via a thin steel wire. The deep base point pawl of the roof delamination meter is arranged in the stable roof strata, serving as a reference point for observing deep roof delamination. It can be considered a fixed point to observe the roof delamination situation below the stable rock strata (at the deep base point). The intermediate-deep base point pawl and shallow base point pawl are arranged to observe the roof delamination settlement within the anchor cable support control range (intermediate-deep and shallow base points). The reading on the roof delamination meter is the amount of delamination settlement of the tunnel roof relative to the deep base point.

[0049] Step 4: Automatic grouting of weak and fractured roof slabs in highway tunnels

[0050] During the construction of Highway 2 tunnel, the grouting pump was in standby mode. When the intelligent control valve 6-2 or 6-4 on the main grouting pipe received a warning signal, it automatically opened immediately. The grouting fluid sequentially passed through the grouting pump station 7, the main grouting pipe 6, the Y-shaped rubber grouting pipe 9, and the grouting pipe of the hollow grouting anchor cable 12 into the fractured rock mass of the weak and broken roof slab 11. When the grouting time or grouting volume reached the set value, the intelligent control valve closed, stopping the grouting, indicating that the grouting of the weak and broken roof slab of one section of the highway tunnel was completed.

[0051] Preferably, the grouting material for the weak and fractured roof is Marisan, which has the characteristics of low viscosity, good adhesion, excellent compressive strength, high expansion rate, and strong flexibility. Marisan and the catalyst liquid solidify 1.5–3 hours after injection into the rock fractures. Grouting parameters: The volume ratio of Marisan resin to catalyst is 1:1, and the weight ratio is 1:1.17. The grouting time is determined according to the grouting requirements of the weak and fractured roof.

[0052] Maresan is a two-component grouting material. The grouting process is as follows: After the multi-functional grouting pump and its accessories are assembled, two suction pipes are inserted into the tank containing Maresan resin and catalyst. The multi-functional grouting pump is started, and the Maresan resin enters the main grouting channel A, while the catalyst enters the main grouting channel B. During the tunnel face advancement, when the delamination of the weak and fractured roof slab in the highway tunnel gradually increases and reaches the set delamination value, the roof delamination instrument issues an early warning. The five pairs of nearby intelligent control valves receive the warning signal from the delamination instrument and automatically open the intelligent control valves. The grout enters the grouting pipe of the weak and fractured roof slab through the Y-shaped rubber hose. After the set grouting time is reached, the multi-functional grouting pump stops grouting. The Y-shaped rubber hose is removed, cleaned with a cleaning agent, and can be reused.

[0053] (5) Dismantle the grouting pipeline equipment

[0054] Once the grouting of the weak and fractured roof slab of a section of the highway tunnel is completed and has solidified, the disposable Y-shaped rubber hose and the reusable digital display early warning device can be removed. After the entire highway tunnel construction is completed, the main grouting pipe is flushed and all pipelines are removed for reuse.

[0055] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived without inventive effort should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An intelligent automated grouting method applicable to the weak and fractured roof slab of deeply buried highway tunnels, characterized in that, Includes the following steps: Step 1: As the tunnel face (4) of the highway tunnel (2) advances, a grouting main system is arranged along the entire length of its sidewall (8). The grouting main system includes a grouting main pipe and a grouting pump connected to the grouting main pipe. The grouting main pipe is also equipped with several grouting main pipe joints with intelligent control valves for branch grouting. Step 2: During the advancement of the tunnel face (4) of the highway tunnel, several hollow grouting anchor cables (12) are installed as branch grouting pipes on the weak and broken roof slab (11) within 10-20m from the tunnel face (4). The hollow grouting anchor cables are connected to the main grouting pipe for grouting. Step 3: As the tunnel face (4) of the highway tunnel advances, a roof monitoring and early warning instrument (13) is quickly deployed in the weak and broken roof slab (11) of the lagging tunnel face to measure the amount of delamination and subsidence in the deep and shallow parts of the weak and broken roof slab (11), thereby determining the timing of grouting. Step 4: During the construction of the highway tunnel, the grouting pump is in standby mode; when the intelligent control valve on the grouting main pipe receives the warning signal from the roof monitoring and early warning instrument (13), it will immediately start automatically and automatically grout the weak and broken roof (11) of the highway tunnel. When the delamination amount and delamination speed of the weak and fractured roof slab of the highway tunnel reach the warning threshold, the warning instrument will automatically issue a warning; the warning signal issued by each roof slab monitoring and warning instrument can be received by 3-6 pairs of nearby intelligent control valves.

2. The intelligent automated grouting method for weak and fractured roof slabs of deeply buried highway tunnels according to claim 1, characterized in that: The steps for arranging the main grouting pipe system along the entire length of a highway tunnel are as follows: First, a grouting pump station is set up near the tunnel wall to house the grouting pump and grouting material; then, the main grouting pipe is fixed in the upper middle part of the wall along the tunnel axis, and is arranged along the entire length of the tunnel, with one end connected to the grouting pump.

3. The intelligent automated grouting method for weak and fractured roof slabs of deeply buried highway tunnels according to claim 1, characterized in that: The main grouting pipe is a steel or plastic round pipe with an internal partition that divides the pipe into two grouting channels: grouting channel A and grouting channel B. Every 2-3 meters along the main grouting pipe, there is a pair of grouting main pipe connectors, each equipped with an intelligent control valve. These connectors are used to connect to branch grouting pipes on the weak and broken roof. One connector is connected to grouting channel A, and the other is connected to grouting channel B. The intelligent control valves are both closed when grouting is not in progress.

4. The intelligent automated grouting method for weak and fractured roof slabs in deeply buried highway tunnels according to claim 1, characterized in that: The hollow grouting anchor cable (12) is installed on the weak and broken top plate through drilling. The drilling is located in the middle of the weak and broken top plate. At least one drilling is arranged in each row. The diameter of the drilling is 32-48mm, the spacing between the drilling is 2-3m, and the drilling depth L is determined according to 1.2 times the thickness of the weak and broken top plate.

5. The intelligent automated grouting method for weak and fractured roof slabs of deeply buried highway tunnels according to claim 1, characterized in that: The hollow grouting anchor cable (12) and the grouting main pipe are connected by a Y-shaped rubber grouting pipe to achieve grouting. The bifurcated hose at one end of the Y-shaped rubber grouting pipe is connected to the intelligent control valve of the grouting main pipe joint on the grouting channel A and the intelligent control valve of the grouting main pipe joint on the grouting channel B respectively. The other end is connected to the grouting pipe joint located at the tail of the hollow grouting anchor cable (12). The Y-shaped rubber grouting pipe is fixed tightly against the surrounding rock.

6. The intelligent automated grouting method for weak and fractured roof slabs of deeply buried highway tunnels according to claim 1, characterized in that: As the tunnel face advances, every 5-15m of the highway tunnel is completed, roof monitoring and early warning instruments are quickly deployed inside the tunnel. The monitoring and early warning instruments are positioned 2m away from the concrete wall and spaced 10m apart to measure the amount of delamination and subsidence in the deep and shallow parts of the weak and broken roof, thereby determining the timing of grouting.

7. The intelligent automated grouting method for weak and fractured roof slabs of deeply buried highway tunnels according to claim 1, characterized in that: The warning threshold of the roof monitoring and early warning instrument is set to two types: ① When the total amount of roof delamination is 150-200mm and the delamination speed is less than 2mm / d, an alarm is triggered; ② When the total amount of roof delamination is greater than 200mm, an alarm is triggered.

8. The intelligent automated grouting method for weak and fractured roof slabs of deeply buried highway tunnels according to claim 1, characterized in that: When the intelligent control valve on the grouting main pipe receives an early warning signal, it will automatically open immediately. The grouting slurry will then pass through the grouting pump, the grouting main pipe, the Y-shaped rubber grouting pipe, and the grouting pipe of the hollow grouting anchor cable into the weak and fractured rock mass of the roof. When the grouting time or grouting volume reaches the set value, the intelligent control valve will close and the grouting will stop, indicating that the grouting of the weak and fractured roof of a section of the highway tunnel is complete.

9. The intelligent automated grouting method for weak and fractured roof slabs of deeply buried highway tunnels according to claim 1, characterized in that: After the grouting of the weak and broken roof of a section of the highway tunnel is completed, and the grouting liquid has solidified, the disposable Y-type rubber grouting pipe and the reusable digital display early warning instrument are removed. After the construction of the entire highway tunnel is completed, the main grouting pipe is flushed and all grouting pipelines are removed for reuse.

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