Construction method for shield tunneling machine to penetrate through anchor cable area

Abstract

The invention relates to the technical field of tunnel engineering, in particular to a construction method for a shield tunneling machine to penetrate through an anchor cable area, an anchor cable is cut off only through double tearing cutters in the tunneling process, and the ground treatment step that the anchor cable is cut through a rotary excavating pile is omitted; the relative heights of the double tearing cutters and other cutters and the cutter head are configured, the double tearing cutters make contact with the intruded anchor cable preferentially and cut off the intruded anchor cable, the free end of the anchor cable is hidden to the back of a pipe piece, anchor cable stumps are discharged along with improved muck after secondary cutting, and the probability that the anchor cable winds around the cutter head is reduced. The technology is applied to shield construction of urban rail transit, effectively solves the difficulty of crossing a long-distance anchor cable section in the shield construction, is not limited by ground construction conditions, improves the construction efficiency, reduces the construction cost, reduces the construction risk, and meets the construction requirements of the urban rail transit.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering, and more particularly to a construction method for a shield machine to pass through an anchor cable area. Background Art

[0002] Shield construction of subway tunnels often requires traversing strata containing anchor cable clusters. These highly resilient anchor cables are buried in the soil and used for slope stabilization and foundation pit support. They are also pre-installed in front of the shield machine to stabilize the surrounding soil, prevent collapse, and maintain the stability of the excavation surface. Improper handling when the shield machine traverses an anchor cable cluster can easily lead to the following problems: First, the cutterhead may fail to sever the anchor cable, causing the cutterhead to rip the entire cable and anchor head, resulting in significant ground disturbance, significant ground subsidence, or even landslides. Second, while the cutterhead can sever the anchor cable, it can entangle the shield machine cutterhead, wearing the cutterhead, increasing the shield machine's torque, and even causing the machine to become trapped, impacting construction progress. Third, once the anchor cable is drawn into the soil compartment, it can easily entangle the screw conveyor, preventing excavation and preventing the shield machine from advancing.

[0003] Therefore, it is necessary to properly handle the construction issues of shield tunneling through anchor cable groups. The common processing technologies currently used mainly include: ground cutting technology for rotary piles, segmented extraction technology using manually bored piles to form a narrow space, cutting and processing with a full-casing rotary drill, and shield opening and cutting extraction technology. The above-mentioned pretreatment technologies are subject to geological conditions, surface environment, surrounding pipelines, and other conditions, and have limitations such as high cost and long construction period. The shield opening and cutting extraction technology has a relatively high risk factor and a large hidden risk. At present, there is no shield machine tool that can get rid of the dependence on stratum pretreatment. The Chinese patent with application number 2024103478521 uses a rotary drill on the ground to preliminarily cut the anchor cable, and then uses a slurry shield mode to pass through the anchor cable area, and uses the double tearing knife of the shield machine cutter head to further cut the anchor cable. The method provided by this patent has the following problems: first, the drill bit or drill rod may entangle or stir the anchor cable, causing soil disturbance and still posing a high construction risk; second, it does not get rid of the reliance on ground cutting technology for rotary piles and cannot be implemented when ground working conditions are limited; finally, the pressure of the shield machine's diverter needs to be monitored during shield tunneling. When the pressure is high, the diverter needs to be opened to clean the anchor cable residues, which is a complicated process and costly. Summary of the Invention

[0004] The present invention aims to overcome at least one of the shortcomings of the above-mentioned prior art and provide a construction method for a shield machine to pass through an anchor cable area, so that the shield machine can cut the anchor cable efficiently, stably and safely without relying on ground pretreatment, thereby facilitating excavation in the anchor cable area.

[0005] The technical solution adopted by the present invention is to provide a construction method for a shield machine to pass through an anchor cable area, comprising the following steps:

[0006] S1. Before shield tunneling, various cutters are installed on the cutterhead of the shield machine;

[0007] S2. When the shield machine approaches the anchor cable area, the shield machine excavation is suspended, the shield machine excavation chamber is opened, some cutters are removed from the cutterhead and double tearing cutters are installed, and excavation parameters for passing through the anchor cable area are set, wherein the excavation parameters include the propulsion speed, the torque threshold, the cutterhead rotation direction, and the synchronous grouting;

[0008] S3. The shield machine adopts earth pressure mode or mud water mode to pass through the anchor cable area. The double tearing knife cuts the anchor cable, and the anchor cable residue is mixed in the slag and discharged by the shield machine. At the same time, the shield machine hides the free end of the anchor cable behind the assembled pipe segment; the shield machine performs synchronous grouting.

[0009] The principle of the above construction method is: remove some cutting tools from the shield machine cutter head and install a double tearing knife. The double tearing knife cuts the anchor cable when the cutter head rotates, and divides it into the free end of the anchor cable and the anchor cable residue. The free end of the anchor cable is squeezed to the tunnel face by the cutter head, and is continuously peeled outward as the shield advances. When the jack stroke is in place, the pipe segments are assembled, and the free end of the anchor cable is naturally hidden behind the pipe segments, leaving the excavation range of the shield machine. The cut anchor cable residue is mixed with the debris cut by the cutter head and discharged.

[0010] The principle behind the naturally concealed free ends of anchor cables is as follows. Since the shield machine is shaped like a horizontal cylinder, segment assembly takes place inside this cylinder. The resulting tunnel has an outer diameter smaller than the cylinder itself, and the shield machine only moves forward after a ring of segments is fully assembled. Therefore, after the anchor cable breaks, the free ends remaining are pushed away by the shield machine and naturally fall outside the segments.

[0011] Compared with existing technologies, this construction method relies solely on dual tearing blades to sever the anchor cables during excavation, eliminating the ground processing step of cutting anchor cables with rotary piles. This method is not restricted by ground construction conditions, improving construction efficiency and reducing construction costs. Furthermore, using a rotary drill on the ground may not accurately sever the anchor cables. The drill bit or drill rod may entangle and agitate the anchor cables, causing soil disturbance. Furthermore, drilling itself disturbs the surrounding strata. Therefore, avoiding rotary drilling is a disturbance-reducing measure, reducing construction risks. The dual tearing blades can be easily replaced during shield tunneling, further improving construction efficiency and emergency response capabilities.

[0012] Furthermore, in step S2, the cutter disc is equipped with a double-tear cutter, a single-edged roller cutter, and a scraper, and the relative heights of the tops of the double-tear cutter, single-edged roller cutter, and scraper to the cutter disc decrease in sequence; the decreasing value of the relative height is 25 to 40 mm; and the relative height of the tops of the double-tear cutter to the cutter disc is 190 to 230 mm. The existing double-tear cutter extension is not set properly and the height is insufficient, so this solution increases its height to about 20 cm above the cutter disc, allowing the double-tear cutter to preferentially contact and cut off the intruding anchor cable; because some of the double-tear cutters are located in the outer area of ​​the cutter disc, the free ends of the anchor cables within the outer edge of the cutter disc are shorter and less likely to entangle on the cutter disc. The arrangement of multiple cutters can increase the probability of cutting the same anchor cable into multiple segments, shorten the length of the anchor cable fragments, and further reduce the probability of the anchor cable fragments entangled in the cutter disc. The cutter heights are set in descending order so that the double tearing cutters with the best cutting effect contact the anchor cable first, increasing the probability of cutting and chopping, reducing the probability of the anchor cable and its fragments being entangled in the cutter disc, and allowing the fragments to enter the excavation chamber through the cutter disc.

[0013] Furthermore, multiple double-tearing blades are arranged in parallel to form a double-tearing blade assembly. Several of these double-tearing blade assemblies are mounted at equal angles on multiple spokes of the cutterhead. Multiple scrapers are located between and on both sides of the double-tearing blade assemblies, and the single-edged rollers are located at the edge of the cutterhead. The single-edged rollers are installed on the edges and spokes of the original cutterhead for general soil excavation. When the shield machine approaches the anchor cable area, excavation is paused, the machine retreats 2-3 cm, and the excavation chamber is opened. The single-edged rollers on the cutterhead's spokes are removed and replaced with double-tearing blades for excavation in the anchor cable area. Soil stability must be ensured during the excavation process. Normal pressure excavation relies primarily on the soil's inherent stability, while pressurized excavation involves forming a sealed chamber and then applying pressure before opening. The single-edged rollers on the cutterhead's edge are not replaced because they have a greater ability to break rock than double-tearing blades. Retaining a sufficient number of rollers ensures the shield machine has a certain degree of rock-breaking capability to complete subsequent excavation. The above-mentioned tool installation position facilitates quick replacement when the shield machine is paused in excavation, which is conducive to shortening the construction period.

[0014] Furthermore, the single-edged hob faces the front of the cutterhead and / or the radially outer side of the cutterhead. Since the single-edged hob is located at the edge of the cutterhead, the single-edged hob facing the radially outer side of the cutterhead is conducive to increasing the cutting trajectory and cutting angle, thereby enhancing the cutterhead's ability to break the anchor cable.

[0015] Furthermore, in step S3, the slurry mode removes anchor cable fragments from the soil through the circulation system. When using the slurry mode to pass through the anchor cable area, the anchor cable fragments are mixed with the mud and enter the shield machine's circulation system. The circulation system is equipped with a diverter to prevent anchor cable fragments from clogging the circulation system. Excessive pressure in the diverter indicates excessive anchor cable accumulation, requiring the diverter to be opened for cleaning, resulting in a cumbersome operation.

[0016] Furthermore, in step S3, the earth pressure mode adds a soil modifier to improve the slag, and the anchor cable fragments in the slag are discharged through the spiral machine of the shield machine. The soil modifiers include bentonite and clay dispersant. When the earth pressure mode is used to pass through the anchor cable area, the anchor cable fragments are mixed with the slag and enter the soil bin. A large amount of bentonite is injected into the soil bin to lubricate the anchor cable, and clay dispersants and other soil modifiers are injected to increase the flow plasticity of the soil, thereby reducing the probability of the anchor cable fragments being entangled with the spiral machine. Therefore, the shield machine should preferably use the earth pressure mode when passing through the anchor cable area, which is relatively simple to operate and has a low failure rate. Another advantage of the earth pressure mode is that the slag pressure is slightly lower than the incision pressure, which is conducive to the shield machine squeezing the soil and allowing the free end of the anchor cable to slide outward in the soil as the shield advances. The incision pressure is achieved by supplementing the air pressure and supplementing the mud.

[0017] Furthermore, in geological conditions where the slurry mode is more suitable, a dual-mode shield machine with both slurry mode and earth pressure mode is used. The slurry mode is used to excavate before reaching the anchor area, and then the slurry mode is switched to the earth pressure mode after passing the anchor area, and then the slurry mode is switched back to continue excavation.

[0018] Furthermore, in step S2, the advancing speed is 20-25 mm / min.

[0019] Furthermore, in step S2, the filling ratio of the synchronous grouting is 1.8-2.0, and the grouting volume is 5-7m 3 / ring. The cutterhead wrapped with anchor cables will increase the disturbance to the soil and cause some soil loss. Therefore, the shield synchronous grouting should increase the filling ratio to 1.8-2.0 and the grouting volume to 5-7m 3 / ring, the slurry is an inert slurry mainly composed of fly ash, bentonite, etc. A second injection of double-liquid slurry is carried out in time at a position 5 rings away from the shield tail to form a water stop ring and fix the tunnel segments.

[0020] Furthermore, in step S2, the torque threshold is 1200-1500 kN·m. To prevent the anchor cable from becoming too entangled and trapping the cutterhead, the cutterhead torque is controlled within the above range or below by adjusting the oil pressure. If torque overload occurs, the machine automatically shuts down and quickly reverses the cutterhead.

[0021] Furthermore, in step S2, the cutterhead rotates clockwise or counterclockwise, and the direction of rotation is changed after every 1-2 rotations. Reducing the cutterhead speed to the minimum and changing the direction of rotation after every 1-2 rotations is beneficial to reducing the possibility of the anchor cable being entangled by the cutterhead blades.

[0022] Furthermore, the double tearing knife includes a knife base and two knife heads. The bottoms of the two knife heads are fixedly connected to the knife base. The two knife heads partially overlap and the tops are bent outward, forming a prismatic surface on the inside. The angle of the knife heads deviating from the shield machine's forward direction does not exceed 45 degrees, and the two knife heads deviate in opposite directions. The prismatic surface refers to the inclined surface formed by chamfering the vertical surface inside the knife head and the top horizontal surface, as well as the chamfering between the vertical surface inside the knife head and the left and right sides. The prismatic surface has multiple edges protruding inward, and the grinding effect is significantly stronger than that of existing knife heads with rectangular cross-sections. The two prismatic surfaces are simultaneously filed against the anchor cable, changing the single track line to a double track line, processing in all directions, and can cut the intruding anchor cable more quickly, thereby avoiding the disturbance of the soil caused by pulling the anchor cable for too long. The outward-bent prismatic surface design of the knife head makes it difficult for the anchor cable to get stuck in the gap between the two knife heads, allowing the shield machine to safely pass through the anchor cable area and reducing construction risks.

[0023] Furthermore, the blade head, viewed from above, has a shape that combines a trapezoid and a rectangle through its long sides, with the outer side of the blade head being wider than the inner side. Viewed from the side, the blade head is arched, with a curved top. This narrower inner side makes it less likely that the anchor cable will become stuck in the gap between the two blade heads. Furthermore, existing double-tear blades have rectangular blade heads with right-angled longitudinal sections. These edges are susceptible to wear, resulting in reduced cutting performance. In contrast, the curved top of the blade head in this embodiment improves wear resistance.

[0024] Furthermore, the spacing between the two blades is 30 to 50 mm. The common diameter specifications of existing soil anchor cables range from 12.7 to 28.6 mm. Therefore, setting the blade spacing of the double tearing knife to more than 30 mm helps reduce the probability of the anchor cable getting stuck in the gap between the two blades.

[0025] Furthermore, the two arcs partially overlap, with the overlapping portion accounting for 50% to 70% of one of the arcs; and the central angle of the arc does not exceed 100°. The partial overlap allows both blades to contact the anchor cable simultaneously, facilitating rapid cutting. Limiting the central angle of the arc makes the blades relatively sharper, enhancing cutting performance.

[0026] Furthermore, the inclination angle of the prismatic surface is 30° to 40°. Compared with a right-angled surface, the prismatic surface with the above inclination angle range can provide a larger effective grinding and filing area when contacting the anchor cable.

[0027] Preferably, the inclination angle of the prismatic surface is 35°.

[0028] Furthermore, the double tearing knife also includes a plug fixed on both sides of the knife seat for connecting the knife disc. The knife disc is provided with a corresponding socket, which is provided in the knife box where the knife is located, so as to facilitate quick replacement.

[0029] Furthermore, the top of the cutter head is provided with a plurality of parallel wear-resistant layers, which extend longitudinally from the prismatic surface on the inner side of the cutter head to the outer side of the cutter head, so that the wear-resistant layers are distributed on both the inner and outer sides of the cutter head, thereby enhancing the grinding and cutting effect.

[0030] Furthermore, the length of the wear-resistant layer on the inner side or outer side of the cutter head is 50 to 100 mm.

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

[0032] The present invention provides a construction method for a shield machine to traverse an anchor cable zone. This method relies solely on cutters to sever the anchor cables during excavation, eliminating the ground treatment step of cutting the anchor cables during rotary drilling. By configuring the relative heights of the dual tearing cutters, other cutters, and the cutterhead, the method preferentially contacts and cuts the intruding anchor cables, hiding the free ends of the anchor cables behind the segments. The anchor cable stubs are then expelled with the modified soil after secondary cutting, reducing the probability of the anchor cables becoming entangled with the cutterhead. This technology, applied to shield construction of urban rail transit, effectively addresses the difficulty of traversing long anchor cable sections during shield construction. It is not restricted by ground construction conditions, improves construction efficiency, reduces construction costs, mitigates construction risks, and meets the requirements of urban rail transit construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a flow chart of a construction method for a shield machine to pass through an anchor cable area provided in Example 1 of the present invention.

[0034] Figure 2 This is a diagram showing the relationship between the cutter head and the tool positions in Example 1 of the present invention.

[0035] Figure 3 This is a schematic diagram of the double tearing knife structure of Example 1 of the present invention.

[0036] Figure 4 Schematic diagram of the double tearing knife prism surface of Example 1 of the present invention.

[0037] Figure 5 This is a top view of the double tearing knife according to embodiment 1 of the present invention.

[0038] Figure 6 3-D view of the double tearing knife of Example 1 of the present invention (unit: mm).

[0039] Figure 7 These are three views of the cutter head according to Example 1 of the present invention (unit: mm).

[0040] Figure 8 This is a front view of the cutter disc of Example 1 of the present invention.

[0041] Explanation of reference numerals: cutter disc 100, replaced single-edged hob 110, double tearing knife 210, knife seat 211, cutter head 212, wear-resistant layer 213, plug 214, prismatic surface 215, single-edged hob 220, scraper 230, anchor head 310, anchor cable 320, anchor cable free end 330, anchor cable remnant 340, wall 400. DETAILED DESCRIPTION

[0042] The accompanying drawings are for illustrative purposes only and are not to be construed as limiting the present invention. To better illustrate the following embodiments, some components in the accompanying drawings may be omitted, enlarged, or reduced in size, and do not represent actual product dimensions. Those skilled in the art will appreciate that some well-known structures and their descriptions may be omitted from the accompanying drawings.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0044] Example 1

[0045] like Figure 2 As shown, there are multiple anchor cables in the soil of the anchor cable area, and an anchor cable 320 is taken as an example. One end of the anchor cable 320 is fixed to the wall 400 through the anchor head 310, and the other end passes through the shield tunnel.

[0046] like Figures 1 to 7 As shown, this embodiment provides a construction method for a shield machine to pass through an anchor cable area, comprising the following steps:

[0047] S1. Before shield tunneling, multiple cutting tools are installed on the cutter head 100 of the shield machine;

[0048] S2. When the shield machine approaches the anchor cable area, the shield machine excavation is suspended, the shield machine excavation chamber is opened, some cutters are removed from the cutterhead 100 and the double tearing cutter 210 is installed, and the excavation parameters for passing through the anchor cable area are set, including the propulsion speed, torque threshold, rotation direction of the cutterhead 100, and synchronous grouting;

[0049] S3. The shield machine uses the earth pressure mode to pass through the anchor area. The double tearing knife 210 cuts the anchor, and the anchor residue 340 is mixed in the slag and discharged by the shield machine. At the same time, the shield machine hides the free end 330 of the anchor behind the assembled segment; the shield machine performs synchronous grouting.

[0050] The principle of the above construction method is: remove some cutting tools from the shield machine cutter head 100 and install a double tearing knife 210. The double tearing knife 210 cuts the anchor cable when the cutter head 100 rotates, and divides it into the anchor cable free end 330 and the anchor cable remnant 340; the anchor cable free end 330 is squeezed to the tunnel face by the cutter head 100, and is continuously peeled outward as the shield machine advances. When the jack stroke is in place, the pipe segments are assembled, and the anchor cable free end 330 is naturally hidden behind the pipe segments, leaving the shield machine excavation range; and the cut anchor cable remnant 340 is mixed with the debris cut by the cutter head 100 and discharged.

[0051] The principle behind the naturally concealed anchor cable free ends 330 is as follows. Since the shield machine is shaped like a horizontal cylinder, segment assembly takes place inside this cylinder. The outer diameter of the assembled tunnel is smaller than the cylinder itself, and the shield machine only moves forward after a ring of segments is fully assembled. Therefore, after the anchor cable breaks, the remaining free ends 330 are pushed aside by the shield machine and naturally fall outside the segments.

[0052] Compared with the existing technology, the above construction method only relies on the double tearing knife 210 to cut the anchor cable during the excavation process, eliminating the ground processing step of the rotary pile cutting anchor cable, and is not restricted by ground construction conditions, thereby improving construction efficiency and reducing construction costs. Secondly, the application of a rotary drill on the ground may not necessarily accurately cut the anchor cable. The drill bit or drill rod may entangle and stir the anchor cable, causing soil disturbance. At the same time, the drilling itself is also a disturbance to the surrounding strata. Therefore, this solution avoids the use of a rotary drill to drill holes, which is itself a measure to reduce disturbance and can reduce construction risks. The double tearing knife 210 can be opened and replaced during shield excavation, which is easy to operate and further improves construction efficiency and emergency response capabilities.

[0053] like Figures 3 to 7As shown, the double tearing blade 210 includes a blade holder 211 and two blade heads 212 welded to the blade holder 211. The two blade heads 212 partially overlap, and their orientation deviates from the shield machine's forward direction by no more than 45 degrees, with the two blade heads 212 deviating in opposite directions. The top of each blade head 212 is bent outward, forming a prismatic surface 215 on the inside. The prismatic surface refers to the inclined surface formed by chamfering the vertical surface inside the blade head and the horizontal surface at the top, as well as the chamfering between the vertical surface inside the blade head and the left and right sides. The prismatic surface has multiple inwardly protruding edges, and its filing effect is significantly stronger than that of existing blade heads with rectangular cross-sections. The two prismatic surfaces 215 are simultaneously filed against the anchor cable, changing the single trajectory into a dual trajectory, achieving all-round processing, and can more quickly cut the intruding anchor cable, thereby avoiding soil disturbance caused by excessive anchor cable pulling. The two cutter heads 212 each measure 140mm x 200mm. When combined, they form a V-shaped cutting surface 255.56mm long and 65mm wide, increasing cutting force. The outward curvature of the cutter heads 212 prevents anchor cables from becoming stuck in the gap between them, allowing the shield machine to safely pass through the anchor cable area and reducing construction risks.

[0054] like Figure 5 As shown, the blade head 212, viewed from above, is a combination of a trapezoid and a rectangle, with the outer side of the blade head 212 being wider than the inner side. Viewed from the side, the blade head 212 is arched, with a curved top. This narrower inner side prevents the anchor cable from becoming lodged in the gap between the two blade heads. Furthermore, conventional double-tear blades have rectangular blade heads with right-angled longitudinal sections. These edges are susceptible to wear, resulting in reduced cutting performance. The curved top of the blade head in this embodiment improves wear resistance.

[0055] like Figure 6 As shown, the distance between the two cutting heads 212 is 40 mm. The common diameter specifications of existing soil anchor cables range from 12.7 to 28.6 mm. Therefore, setting the distance between the cutting heads 212 of the double tearing knife to more than 30 mm helps reduce the probability of the anchor cable getting stuck in the gap between the two cutting heads.

[0056] like Figure 6 As shown, the two arcs at the top of the blade head partially overlap, with the overlap accounting for 50% to 70% of one of the arcs. The central angle of the arc does not exceed 100°. This partial overlap allows both blades 212 to contact the anchor cable simultaneously, facilitating faster cutting. Limiting the central angle of the arc makes the blade head relatively sharper, enhancing cutting performance.

[0057] like Figure 7 As shown in FIG. 1 , the inclination angle of the prism surface is 35°. Compared with a right-angle surface, the prism surface with the above inclination angle can provide a larger effective grinding area when contacting the anchor cable.

[0058] In terms of material, the cutter head 212 is made of tungsten steel KE15 with a bending strength of 1480 MPa, and the cutter seat 211 is made of 42CrMo steel, which is a high-strength alloy structural steel with a tensile strength of σ b ≥1080MPa. Tungsten steel KE15 density 14.5g / cm 3 , the hardness is 88HRA, which is 30% higher than ordinary alloy steel, and the bending strength is 1480MPa, which is 25% higher. Combined with the high tensile strength of 42CrMo tool holder 211, it can effectively withstand the impact of anchor cables.

[0059] When the cutter head 212 and the cutter seat 211 are welded, a silver brazing process is used, and the weld strength is ≥ 240 MPa. After welding, a heat preservation and slow cooling treatment is required to prevent the weld from cracking due to rapid cooling. The above process ensures that the weld strength reaches above 240 MPa.

[0060] The top of the blade 212 is provided with multiple parallel wear-resistant layers 213. These layers extend longitudinally from the inner prismatic surface to the outer side of the blade 212. They are 3 mm thick and 3 mm from the edge of the alloy groove. They are produced using a laser cladding process. The wear-resistant layers 213 are 50 to 100 mm long on either the inner or outer side of the blade 212. Distributing the wear-resistant layers 213 on both the inner and outer sides of the blade 212 enhances the cutting effect.

[0061] The double tearing knife 210 for cutting the anchor rope also includes a plug 214, which is fixed on both sides of the knife seat 211 and is used to connect to the knife disc 100. The knife disc 100 is provided with a corresponding socket 110, which is provided in the knife box where the knife is located for easy replacement.

[0062] like Figure 8 As shown, in step S2, the cutting tools installed on the cutterhead 100 include double tearing knives 210, single-edged roller cutters 220 and scrapers 230. A plurality of the double tearing knives 210 are arranged in parallel to form a double tearing knife 210 group. Several of the double tearing knife 210 groups are installed at equal angles on multiple radial lines of the cutterhead 100. A plurality of scrapers 230 are located between and on both sides of the double tearing knife 210 group. The single-edged roller cutters 220 are located at the edge of the cutterhead 100. Some of the single-edged roller cutters 220 face the front of the cutterhead, and the other part of the single-edged roller cutters 220 face the radial outside of the cutterhead. The original single-edged roller cutters 220 are installed on the edge and radial lines of the cutterhead 100 for excavation of general soil. When the shield machine approaches the anchor cable area, the shield excavation is suspended, the shield machine excavation chamber is opened, and the single-edged roller cutters at the radial lines on the cutterhead 100 are removed and replaced with double tearing knives 210 for excavation in the anchor cable area. The replaced single-edged roller cutters 110 are shown in FIG. Figure 6As shown, it can be seen that the height of the double tearing knife 210 relative to the cutter disc 100 is significantly higher than the replaced single-edged roller cutter 110. The soil needs to be stable during the opening process. The normal pressure opening mainly relies on the stability of the soil itself, while the pressure opening is to form the soil bin into a closed space and then pressurize it before opening. The single-edged roller cutter at the edge of the cutter disc is not replaced because the roller cutter has a stronger ability to break the rock layer than the double tearing knife. Retaining a certain number of roller cutters can ensure that the shield machine has a certain degree of rock breaking ability to complete the subsequent excavation construction. The above-mentioned tool installation position facilitates quick replacement when the shield machine excavation is suspended, which is conducive to shortening the construction period.

[0063] like Figure 2 As shown, the relative heights of the tops of the dual-tear blades 210, single-edged roller cutter 220, and scraper 230 relative to the cutter disc 100, i.e., the cutting point heights, decrease in sequence to 200mm, 175mm, and 135mm, respectively. The spacing between adjacent blades of different types is at least 25mm. The existing dual-tear blades 210 have unreasonable extension settings and insufficient height. Therefore, this solution increases their height, approximately 20cm above the cutter disc 100, allowing the dual-tear blades 210 to preferentially contact and sever intruding anchor cables. Because a portion of the dual-tear blades 210 are located near the outer edge of the cutter disc 100, the free ends 330 of the anchor cables within the outer edge of the cutter disc 100 are shorter, making them less likely to become entangled in the cutter disc 100. The existing cutting tools have only one or two cutting trajectory lines, which have limited effect on breaking the anchor cable. However, this embodiment provides three trajectory lines, including a double tearing knife 210, a single-edged roller 220 and a scraper 230. The cutting point height is also improved from the existing 175mm~135mm to 200mm~175mm~135mm, with richer levels, so that tools of different heights act on the same point at different levels of the anchor cable. The anchor cable invading the shield tunnel section can be effectively disconnected from the anchor head section and cut into multiple small sections in a layered manner, shortening the length of the anchor cable segment 340, further reducing the probability of the anchor cable wrapping around the cutter head 100, and allowing the fragments to enter the soil bin through the cutter head 100, which is beneficial for the shield machine to discharge the anchor cable segment 340.

[0064] In step S3, the earth pressure mode adds a soil modifier to improve the slag, and the anchor cable stubs 340 in the slag are discharged through the shield machine's screw machine. The soil modifiers include bentonite and clay dispersants. When the earth pressure mode is used to pass through the anchor cable area, the anchor cable stubs 340 are mixed with the slag and enter the soil bin. A large amount of bentonite is injected into the soil bin to lubricate the anchor cable, and clay dispersants and other soil modifiers are injected to increase the soil flow plasticity, thereby reducing the probability of the anchor cable stubs 340 being entangled in the screw machine. Therefore, the earth pressure mode should be preferred when the shield machine passes through the anchor cable area. The operation is relatively simple and the failure rate is low. Another advantage of the earth pressure mode is that the slag pressure is slightly lower than the incision pressure, which is conducive to the shield machine squeezing the soil and allowing the free end 330 of the anchor cable to slide outward in the soil as the shield advances. The incision pressure is achieved by supplementing air pressure and mud.

[0065] In geological conditions where the slurry mode is more suitable, a dual-mode shield machine with both slurry mode and earth pressure mode is used. The slurry mode is used to excavate before reaching the anchor area, and then the slurry mode is switched to the earth pressure mode after passing the anchor area, and then the slurry mode is switched back to continue excavation.

[0066] In step S2, the advancing speed is 20-25 mm / min.

[0067] In step S2, the filling ratio of the synchronous grouting is 1.8-2.0, and the grouting volume is 5-7m 3 / ring. The cutterhead 100 wrapped with anchor cables will increase the disturbance to the soil and cause some soil loss. Therefore, the shield synchronous grouting should increase the filling ratio to 1.8-2.0 and the grouting volume to 5-7m 3 / ring, the slurry is an inert slurry mainly composed of fly ash, bentonite, etc. A second injection of double-liquid slurry is carried out in time at a position 5 rings away from the shield tail to form a water stop ring and fix the tunnel segments.

[0068] In step S2, the torque threshold is 1200-1500 kN·m. To prevent the anchor cable from becoming entangled and trapping the cutterhead 100, the oil pressure is set to control the torque of the cutterhead 100 within the above range or below. If the torque is overloaded, the machine automatically shuts down and quickly reverses the cutterhead 100.

[0069] In step S2, the cutterhead 100 rotates clockwise or counterclockwise, and the cutterhead 100 changes its rotation direction after every 1-2 rotations. Reducing the speed of the cutterhead 100 to the minimum and changing its rotation direction after every 1-2 rotations helps reduce the possibility of the anchor cable being entangled by the cutters of the cutterhead 100.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] The present invention provides a construction method for a shield machine to traverse an anchor cable zone. This method relies solely on cutters to sever the anchor cables during excavation, eliminating the ground treatment step required for drilling piles to cut the anchor cables. By configuring the relative heights of the dual tearing cutters 210, other cutters, and the cutterhead 100, the system preferentially contacts and severs intruding anchor cables, hiding the free ends 330 of the anchor cables behind the segments. The anchor cable stubs 340 are then expelled with the modified soil after secondary cutting, reducing the probability of the anchor cables becoming entangled with the cutterhead 100. This technology, applied to shield tunneling in urban rail transit, effectively addresses the difficulty of traversing long anchor cable sections during shield tunneling. Unrestricted by ground construction conditions, it improves construction efficiency, reduces construction costs, mitigates construction risks, and meets the requirements of urban rail transit construction.

[0072] Example 2

[0073] This embodiment differs from Example 1 only in that, in step S3, a muddy water mode is used to pass through the anchor cable area. This muddy water mode removes anchor cable fragments from the soil through a circulation system. The anchor cable fragments, mixed with mud, enter the shield machine's circulation system. The circulation system is equipped with a diverter to prevent anchor cable fragments from clogging the circulation system. Excessive pressure in the diverter indicates excessive anchor cable accumulation, requiring the diverter to be opened for cleaning, a cumbersome operation.

[0074] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A construction method for a shield machine to pass through an anchor cable area, characterized in that: The following steps are involved: S1. Before shield tunneling, various cutters are installed on the cutterhead of the shield machine; S2. When the shield machine approaches the anchor cable area, the shield machine excavation is suspended, the shield machine excavation chamber is opened, some cutters are removed from the cutterhead and double tearing cutters are installed, and excavation parameters for passing through the anchor cable area are set, including the propulsion speed, the cutterhead rotation direction, and the synchronous grouting; S3. The shield machine adopts earth pressure mode or mud water mode to pass through the anchor cable area. The double tearing knife cuts the anchor cable, and the anchor cable residue is mixed in the slag and discharged by the shield machine. At the same time, the shield machine hides the free end of the anchor cable behind the assembled pipe segment; the shield machine performs synchronous grouting.

2. A construction method for a shield machine passing through an anchor cable area according to claim 1, characterized in that: In step S2, the cutting tools installed on the cutter disc include a double tearing knife, a single-edged rolling knife and a scraper, and the relative heights of the top ends of the double tearing knife, the single-edged rolling knife and the scraper to the cutter disc decrease in sequence.

3. A construction method for a shield machine passing through an anchor cable area according to claim 2, characterized in that: The decreasing value of the relative height is 25 to 40 mm.

4. The construction method of a shield machine passing through an anchor cable area according to claim 2, characterized in that: The relative height between the top of the double tearing knife and the knife disc is 190-230 mm.

5. The construction method of a shield machine passing through an anchor cable area according to claim 2, characterized in that: Multiple double tearing knives are arranged in parallel to form a double tearing knife group, several double tearing knife groups are installed at equal angles on multiple spokes of the knife disc, multiple scrapers are located between and on both sides of the double tearing knife group, and the single-edged hob is located at the edge of the knife disc.

6. A construction method for a shield machine to pass through an anchor cable area according to any one of claims 1 to 5, characterized in that: In step S3, the mud-water mode discharges the anchor cable residues in the slag through the circulation system.

7. A construction method for a shield machine to pass through an anchor cable area according to any one of claims 1 to 5, characterized in that: In step S3, the soil modifier is added to improve the slag in the earth pressure mode, and the anchor cable fragments in the slag are discharged by the screw machine of the shield machine.

8. The construction method of a shield machine passing through an anchor cable area according to claim 7, characterized in that: The soil modifier includes bentonite and clay dispersant.

9. A construction method for a shield machine to pass through an anchor cable area according to any one of claims 1 to 5, characterized in that: In step S2, the cutter disc rotates clockwise or counterclockwise, and the cutter disc changes its rotation direction after every 1 to 2 rotations.

10. A construction method for a shield machine passing through an anchor cable area according to any one of claims 1 to 5, characterized in that: The double tearing knife includes a knife seat and two knife heads. The bottoms of the two knife heads are fixedly connected to the knife seat. The two knife heads partially overlap and the tops are bent outward, forming a prismatic surface on the inside. The angle of the knife head deviating from the forward direction of the shield machine does not exceed 45° and the deviation directions of the two knife heads are opposite.

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