A shield cutter suitable for a composite stratum with soft upper and hard lower layers and a configuration method thereof

Abstract

The application discloses a shield cutter disc suitable for a soft-hard composite stratum and a configuration method thereof. The shield cutter disc comprises a cutter disc body, a plurality of main rib plates are arranged on a cutter face of the cutter disc body along the radial direction of the cutter face, a plurality of double-blade rollers are arranged on each main rib plate at intervals, the double-blade rollers are arranged on the main rib plates through cutter barrels, and a mud guard is arranged in the cutter barrel; rib plates are arranged or not arranged between two adjacent main rib plates according to a required opening rate of the cutter disc, and the number of the arranged rib plates is determined; the shield cutter disc is suitable for shield tunneling construction of the soft-hard composite stratum, can effectively reduce the situation of mud cake on the cutter disc, improve the liquidity of the soil in the cabin, reduce the frequency of inspection and replacement of the rollers, thereby reducing the construction cost and improving the shield construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) construction technology, specifically to a TBM cutterhead and its configuration method suitable for composite strata with soft upper and hard lower layers. Background Technology

[0002] In recent years, with the country's investment in transportation infrastructure construction increasing year by year, shield tunneling has been used more and more widely in underground tunnel construction, and its application environment has become increasingly complex.

[0003] Shield tunneling is generally suitable for relatively homogeneous strata. However, due to the randomness and complexity of geological environments in nature, geological interfaces are undulating, and encountering composite strata with soft upper layers and hard lower layers has become a common occurrence during shield tunneling. In these strata, the clay mineral content is high while the water content is low, resulting in poor flowability of the excavated soil. This makes it easier for the soil to accumulate on the cutterhead, forming mud cakes, which reduces the shield tunneling speed, increases cutter wear, and significantly reduces tunneling efficiency, thus delaying the construction process. Furthermore, existing shield machines cannot fully adapt to composite strata with soft upper layers and hard lower layers. Abnormal wear of the cutterhead and cutters frequently occurs, and the distribution and installation of cutter components such as the fishtail scraper, toothed cutter, edge scraper, tearing cutter, and spoke ribs are not always appropriate. In particular, mud cake formation is extremely common, severely impacting shield tunneling efficiency. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a cutterhead and its configuration method suitable for composite strata with soft upper and hard lower layers. By changing the shape of the cutterhead, cutters, and cutter cylinder, it alleviates the problem of mud cake formation caused by the poor fluidity and high viscosity of the cut soil in composite strata, which leads to a decrease in tunneling speed of the tunnel boring machine and a significant increase in cutter wear, seriously affecting the efficiency of tunnel boring machine construction.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect of the invention, a shield cutterhead suitable for composite strata with soft upper and hard lower layers is provided, comprising a cutterhead body, wherein multiple main ribs are arranged radially along the cutter surface of the cutterhead body, and multiple double-edged cutters are arranged at intervals on each main rib, wherein the double-edged cutters are mounted on the main ribs through a cutter cylinder, and a mudguard is provided inside the cutter cylinder; ribs are selectively provided or not provided between two adjacent main ribs according to the required cutterhead opening ratio, and the number of ribs provided is determined.

[0007] In some embodiments of the present invention, the double-edged hob includes two toothed hobs, and a plurality of V-shaped cutting teeth are provided on the circumferential surface of the toothed hob. The cutting edges of the plurality of V-shaped cutting teeth are in the same direction and are evenly distributed along the circumferential direction of the toothed hob.

[0008] In some embodiments of the present invention, a weld overlay layer is provided on the circumferential position on both sides of the V-shaped cutting teeth on the toothed hob, and the thickness of the weld overlay layer is 45-55mm.

[0009] In some embodiments of the present invention, one end of the cutter barrel is provided with a cutter limiting groove for mounting a double-edged hob, and the other end is provided with a mounting base, through which the cutter barrel is mounted on the main rib plate on the cutter disc.

[0010] In some embodiments of the present invention, the mudguard is disposed at the rear of the double-edged roller cutter inside the cutter barrel, and the mudguard has an irregular rectangular structure.

[0011] In some embodiments of the present invention, the double-edged hobs are arranged in a star-shaped pattern from the center to the edge of the cutter disc. The multiple double-edged hobs located at the center of the cutter disc are irregularly arranged, while the axes of the multiple double-edged hobs located on the outer periphery of the center of the cutter disc are all arranged radially along the cutter disc.

[0012] In some embodiments of the present invention, a plurality of leading blades are evenly spaced on the outer periphery of the cutter head body, and the height of the leading blades is 5-15mm higher than the height of the double-edged hob.

[0013] In a second aspect of the invention, a method for configuring a shield cutterhead suitable for composite strata with a soft upper layer and a hard lower layer is provided. The shield cutterhead before configuration includes a cutterhead body with multiple main ribs. Multiple tearing cutters or smooth rolling cutters are mounted on the main ribs. Ribs are provided between adjacent main ribs, with the ribs close to the circumferential edge of the cutterhead and fixed by multiple rib spokes. The method is characterized in that, during shield tunneling, when encountering composite strata with a soft upper layer and a hard lower layer, the shield cutterhead before configuration cannot meet the requirements of such strata. Therefore, the shield cutterhead is configured as follows:

[0014] Replace the tearing blade or smooth hob on the original cutter head with a double-edged hob.

[0015] The double-edged hob is mounted on the cutter head via a cutter barrel, and a mudguard is installed inside the cutter barrel.

[0016] In some embodiments of the present invention, removing the ribs on the cutter head near the circumference of the cutter head includes:

[0017] Based on the specific geological conditions, determine the cutterhead opening ratio, the location where the ribs need to be removed, and the number of spokes to be cut;

[0018] The edge rib spokes are cut off one by one using a cutting machine. After each spoke is cut off, the stiffness of the cutter head at that location and around it is tested to ensure the overall stability of the cutter head.

[0019] After the surrounding spokes are removed, the shaft ribs are removed. After the removal is completed, the stiffness of the cutter head is checked.

[0020] If the rigidity is up to standard, it can continue to be used. If the rigidity is compromised, the cutter head should be reinforced immediately.

[0021] In some embodiments of the present invention, the double-edged hob includes two toothed hobs, wherein a plurality of V-shaped cutting teeth are uniformly arranged on the circumferential surface of the toothed hob, and the cutting edges of the plurality of V-shaped cutting teeth are in the same direction and along the circumferential direction of the toothed hob.

[0022] One or more technical solutions of the present invention have the following beneficial effects:

[0023] (1) The shield cutterhead provided by the present invention is suitable for composite strata with soft upper and hard lower layers. By selecting to set or not setting ribs between adjacent main ribs and by determining the number of ribs set, the opening ratio of the cutterhead can be changed to achieve the required cutterhead opening ratio. While ensuring the strength of the cutterhead, the cutterhead has a larger opening ratio, thereby improving the fluidity of the excavated soil in the excavation chamber and effectively alleviating the mud cake situation.

[0024] (2) The shield cutterhead provided by the present invention, which is suitable for composite strata with soft upper and hard lower layers, is equipped with toothed cutters. By forming a double-edged cutter with two toothed cutters, the tunneling force can be increased in a certain area, thereby reducing the wear of a single cutter and improving the tunneling efficiency. By setting a weld overlay layer on both sides of the toothed cutter, the cutter wear under the condition of mud cake can be effectively prevented, reducing the wear of the cutter. By using V-shaped cutter teeth, it can not only break hard rock, but also increase the friction with soft soil due to the V-shaped cutter surface, which can better adapt to soft soil strata, avoid the cutter from spinning idly, and improve the tunneling efficiency of composite strata with soft upper and hard lower layers.

[0025] (3) The shield cutterhead provided by the present invention is suitable for composite strata with soft upper and hard lower layers. The cutters are arranged irregularly and densely at the center position. The empty positions are convenient for later installation of high-pressure jetting devices to assist the central cutter in excavation. The cutters around the center are arranged in a relatively uniform cross shape to ensure high tunneling efficiency and uniform stress on the tunnel face, and maintain the stability of the tunnel face.

[0026] (4) The shield cutterhead provided by the present invention, which is suitable for composite strata with soft upper and hard lower layers, can prevent clay clumps from entering the cavity behind the cutter after mud cake formation occurs in the guide tube by setting a mud baffle inside the guide tube, ensuring that the cutter does not wear unevenly and can rotate normally for a long time, reducing the frequency of inspection and cutter replacement, thereby reducing construction costs and improving construction efficiency.

[0027] (5) The method for configuring a shield cutterhead suitable for composite strata with soft upper layer and hard lower layer provided by the present invention directly changes the cutterhead opening ratio by cutting ribs on the existing cutterhead, thereby improving the fluidity of the excavated soil in the excavation chamber without affecting the rigidity and strength of the cutterhead and effectively alleviating the mud cake situation; by changing the shape of the cutter and the cutter cylinder, the mud cake situation in composite strata with soft upper layer and hard lower layer is reduced and there is no uneven wear, thereby improving the tunneling speed of the shield; the method provided by the present invention does not require the design or replacement of a new cutterhead, but only requires modification of the existing cutterhead, which will not delay the construction progress and also reduces costs. Attached Figure Description

[0028] Figure 1 This is an overall structural diagram of the shield cutterhead of the present invention, applicable to composite strata with soft upper and hard lower formations;

[0029] Figure 2 This is a schematic diagram of the toothed hob of the present invention;

[0030] Figure 3 This is a schematic diagram of the V-shaped cutting tooth structure of the present invention;

[0031] Figure 4 This is a schematic diagram of the external structure of the knife barrel of the present invention;

[0032] Figure 5 This is a schematic diagram of the internal structure of the cutter barrel of the present invention.

[0033] In the diagram: 1. Rib plate structure before removal; 101. Rib plate spokes; 102. Shaft rib plate; 2. Structure after rib plate removal; 3. Toothed hob; 4. V-shaped cutter teeth; 5. Lead cutter; 6. Weld overlay; 7. Cutter barrel; 8. Double-edged hob; 9. Cutter limiting groove; 10. Mudguard; 11. Main rib plate; 12. Mounting base. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] Example 1

[0036] In a typical embodiment of the present invention, such as Figures 1-5 As shown, a shield cutterhead suitable for composite strata with soft upper and hard lower formations is proposed, including a cutterhead body. Multiple main ribs 11 are arranged radially along the cutterhead surface of the cutterhead body. Multiple double-edged cutters 8 are arranged at intervals on each main rib 11. The double-edged cutters 8 are mounted on the main ribs 11 through a cutter cylinder 7. A mudguard 10 is arranged inside the cutter cylinder 7. The number of ribs is determined by selecting whether to set ribs between two adjacent main ribs 11 according to the required cutterhead opening ratio.

[0037] The cutterhead opening ratio refers to the ratio of the area of ​​the opening portion of the cutterhead to the area of ​​the cutterhead itself. A larger opening ratio allows for smoother flow of excavated soil. The opening ratio of existing shield cutterheads is relatively small, generally not exceeding 30%. The opening ratio of the cutterhead can be changed by selecting or not setting ribs between adjacent main ribs, and by determining the number of ribs to be set. While ensuring the strength of the cutterhead, a larger opening ratio can be achieved to improve the fluidity of excavated soil in the excavation chamber and effectively alleviate the problem of mud cake formation.

[0038] In this embodiment, six main ribs are provided. One end of the six main ribs intersects at the center of the cutter head body, and the other end is connected to the circumference of the cutter head body. Figure 1 As shown, the main rib plate 11, located near the periphery of the cutter head body, is fan-shaped, which can effectively increase the connection area between the main rib plate and the periphery of the cutter head body, thereby improving the overall strength of the cutter head.

[0039] like Figure 2 and Figure 3 As shown, the double-edged cutter 8 includes two toothed cutters 3. Multiple V-shaped teeth 4 are evenly arranged on the circumferential surface of each toothed cutter 3. The cutting edges of the multiple V-shaped teeth 4 are in the same direction and along the circumference of the toothed cutter. The V-shaped cutter teeth can break through hard rock, and due to the V-shaped cutting surface, the friction with soft soil is increased, allowing for better adaptation to soft soil strata, preventing the cutter from spinning idly, and improving the tunneling efficiency in composite strata with a soft upper layer and a hard lower layer.

[0040] Furthermore, a weld overlay layer 6 is provided on the toothed hob 3 at the circumferential position on both sides of the V-shaped cutter teeth 4. The thickness of the weld overlay layer is 45-55mm, preferably 50mm. The weld overlay layer can effectively prevent the cutter from wearing out due to mud cake formation, reduce the wear of the cutter, and improve the tunneling speed of the shield.

[0041] like Figure 4As shown, one end of the cutter barrel is provided with a cutter limiting groove 9 for installing double-edged cutters. Two cutter limiting grooves 9 are provided, and two toothed cutters are fixed in the cutter limiting grooves at the top of the cutter barrel. By adding double-edged cutters to the cutter barrel, the tunneling force can be increased in a certain area, thereby reducing the wear of individual cutters and improving tunneling efficiency. The other end of the cutter barrel is provided with a mounting base 12, through which the cutter barrel is mounted on the main rib plate 11 on the cutterhead. The cutter limiting groove 9 is an irregularly shaped rectangular groove. The mudguard 10 is located at the rear of the double-edged cutter inside the cutter barrel 7, i.e., at the bottom of the cutter limiting groove 9. The mudguard 10 has an irregularly shaped rectangular structure, and the distance between the mudguard and the cutter is relatively close, preventing the entering clay from accumulating. The mudguard prevents clay clumps from entering the cavity behind the cutter after mud cake formation, ensuring that the cutter does not experience uneven wear and can rotate normally for a long time, reducing the frequency of inspection and cutter replacement, thereby reducing construction costs and improving construction efficiency.

[0042] In this embodiment, the double-edged roller cutters are arranged in a star-shaped pattern from the center to the edge of the cutterhead. Multiple double-edged roller cutters located at the center of the cutterhead are irregularly arranged, while the axes of multiple double-edged roller cutters located on the outer periphery of the center are all arranged radially along the cutterhead. The irregular and dense arrangement of the roller cutters at the center allows for the later installation of high-pressure jetting devices to assist the central roller cutters in excavation. The more uniform star-shaped arrangement of the surrounding roller cutters ensures high tunneling efficiency and uniform stress on the tunnel face, maintaining its stability.

[0043] In this embodiment, a plurality of leading blades 5 are evenly spaced on the outer periphery of the cutter head body, and the height of the leading blades 5 is 5-15mm higher than the height of the double-edged hob.

[0044] The working method of the shield tunneling cutterhead suitable for composite strata with soft upper and hard lower layers provided in this embodiment is as follows:

[0045] The peripheral cutters on the shield cutterhead break through the rock, soil, and clay; the rolling cutters scrape away the soil on the working face; the scraped clay falls to the bottom of the excavation chamber and is transported away at the cutterhead opening.

[0046] Example 2

[0047] As described in the background section, existing shield tunneling cutterheads are suitable for homogeneous strata. However, when encountering composite strata with a soft upper layer and a hard lower layer, the existing cutterheads suffer from mud cake accumulation and cutter wear due to their small opening ratio and unreasonable cutter arrangement. Directly redesigning or replacing the cutterhead in this situation would delay construction and increase costs. Therefore, this embodiment proposes a method for modifying existing shield tunneling cutterheads, specifically a configuration method for shield tunneling cutterheads suitable for composite strata with a soft upper layer and a hard lower layer. The original shield tunneling cutterhead includes a cutterhead body with multiple main ribs. Multiple tearing cutters or smooth rolling cutters are mounted on the main ribs. Ribs are positioned between adjacent main ribs, close to the circumferential edge of the cutterhead, and fixed by multiple rib spokes. During tunneling, when encountering composite strata with a soft upper layer and a hard lower layer, the original shield tunneling cutterhead cannot meet the requirements of such strata. The following configuration is applied to the shield tunneling cutterhead:

[0048] Step 1: Remove the ribs on the cutter head near the circumferential edge of the cutter head:

[0049] Since the removed ribs are located at a relatively edge of the cutterhead, removing this portion of the ribs will not affect the rigidity and strength of the cutterhead itself. This allows for improved flowability of the excavated soil within the excavation chamber without compromising the cutterhead's rigidity and strength, effectively alleviating mud cake formation. In actual engineering projects, the number of ribs to be removed can be determined based on the severity of mud cake formation. The rib removal measures are as follows:

[0050] (1) Determine the cutterhead opening ratio, the location of the rib plate to be removed, and the number of spokes to be removed based on the specific geological conditions. Specifically, the greater the viscosity of the geological formation and the more serious the mud cake situation, the greater the cutterhead opening ratio. When removing the rib plate, ensure that the cutterhead stiffness is not affected.

[0051] (2) Figure 1 As shown, the edge rib spokes 101 are cut off sequentially using a cutting machine. After each spoke is cut off, the stiffness of the cutter head at that location and around it is tested to ensure the overall stability of the cutter head.

[0052] (3) After the peripheral spokes 101 are removed, the shaft rib 102 is removed. After the removal is completed, the cutter head stiffness is tested; by comparison... Figure 1 The specific cutting location can be seen in the images of structure 1 (without rib removal) and structure 2 (after rib removal).

[0053] (4) If the stiffness is qualified, it can continue to be used. If the stiffness is damaged, the cutter head should be reinforced immediately.

[0054] Step 2: Replace the existing tearing cutter or smooth roller cutter on the cutter head with a double-edged roller cutter. Tearing cutters and smooth roller cutters are suitable for hard rock formations and are used for rock breaking. However, when encountering a composite formation with soft upper and hard lower layers, the tearing cutter and smooth roller cutter have less friction, are prone to uneven wear, and have greater wear. In contrast, toothed roller cutters are more effective in highly viscous formations.

[0055] Step 3: The double-edged hob is mounted on the cutter head through a cutter tube, and a mudguard is installed inside the cutter tube.

[0056] In this embodiment, the double-edged cutter includes two toothed cutters. Multiple V-shaped teeth are evenly arranged on the circumferential surface of each toothed cutter. The cutting edges of these V-shaped teeth are aligned in the same direction and along the circumference of the cutter. The V-shaped cutter teeth can break through hard rock, and due to the V-shaped cutting surface, they increase the friction with soft soil, allowing for better adaptation to soft soil strata, preventing the cutter from spinning freely, and improving the tunneling efficiency in composite strata with a soft upper layer and a hard lower layer.

[0057] This embodiment improves the fluidity of excavated soil in the excavation chamber and effectively alleviates mud cake formation by directly altering the cutterhead opening ratio through cutting ribs on the existing cutterhead, without affecting the cutterhead's rigidity and strength. By changing the shape of the cutterhead and cutter cylinder, mud cake formation in composite strata with soft upper and hard lower layers is reduced without causing uneven wear, thus increasing the tunneling speed of the shield tunnel. The method provided in this embodiment does not require the design or replacement of a new cutterhead; it can be implemented simply by modifying the existing cutterhead, without delaying the construction progress and reducing costs.

[0058] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for configuring a shield tunnel cutterhead suitable for composite strata with a soft upper layer and a hard lower layer, wherein the shield tunnel cutterhead before configuration includes a cutterhead body, multiple main ribs are provided on the cutterhead body, multiple tearing cutters or smooth rolling cutters are installed on the main ribs, and ribs are provided between adjacent main ribs, the ribs are close to the circumferential edge of the cutterhead, and the ribs are fixed by multiple rib spokes, characterized in that, During tunnel boring machine (TBM) operations, when encountering a composite stratum with a soft upper layer and a hard lower layer, the pre-configured cutterhead cannot meet the requirements of this stratum. Therefore, the cutterhead is configured as follows: Remove the ribs on the cutter head near the circumferential edge of the cutter head; Replace the tearing blade or smooth hob on the original cutter head with a double-edged hob. The double-edged hob is mounted on the cutter head via a cutter barrel, and a mudguard is installed inside the cutter barrel; The double-edged hob includes two toothed hobs, each with multiple V-shaped teeth on its circumferential surface. The cutting edges of the multiple V-shaped teeth are in the same direction and are evenly distributed along the circumferential direction of the toothed hob. A weld overlay layer with a thickness of 45-55mm is provided on the circumference of the toothed hob on both sides of the V-shaped tooth.

2. The method for configuring a shield cutterhead suitable for composite strata with a soft upper layer and a hard lower layer as described in claim 1, characterized in that, One end of the cutter barrel is provided with a cutter limiting groove for installing a double-edged hob, and the other end is provided with a mounting base, through which the cutter barrel is mounted on the main rib plate on the cutter disc.

3. The method for configuring a shield cutterhead suitable for composite strata with a soft upper layer and a hard lower layer as described in claim 1, characterized in that, The mudguard is located at the rear of the double-edged roller cutter inside the cutter barrel, and the mudguard has an irregular rectangular structure.

4. The method for configuring a shield cutterhead suitable for composite strata with a soft upper layer and a hard lower layer as described in claim 1, characterized in that, The double-edged hobs are arranged in a star-shaped pattern from the center to the edge of the cutter head. The multiple double-edged hobs located at the center of the cutter head are irregularly arranged, while the axes of the multiple double-edged hobs located on the outer periphery of the cutter head are all arranged radially along the cutter head.

5. The method for configuring a shield cutterhead suitable for composite strata with a soft upper layer and a hard lower layer as described in claim 1, characterized in that, Multiple leading blades are evenly spaced on the outer periphery of the cutter head body, and the height of the leading blades is 5-15mm higher than that of the double-edged hob.

6. The method for configuring a shield cutterhead suitable for composite strata with a soft upper layer and a hard lower layer as described in claim 1, characterized in that, Removing the ribs on the cutter head near the circumference of the cutter head includes: Based on the specific geological conditions, determine the cutterhead opening ratio, the location where the ribs need to be removed, and the number of spokes to be cut; The edge rib spokes are cut off one by one using a cutting machine. After each spoke is cut off, the stiffness of the cutter head at that location and around it is tested to ensure the overall stability of the cutter head. After the surrounding spokes are removed, the shaft ribs are removed. After the removal is completed, the stiffness of the cutter head is checked. If the rigidity is up to standard, it can continue to be used. If the rigidity is compromised, the cutter head should be reinforced immediately.

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