Method for reducing cost and increasing efficiency of cutter of cutter head in shield construction in composite stratum

Abstract

The application discloses a method for reducing cost and increasing efficiency of a cutter of a cutter head of a shield construction in a composite stratum, and can effectively reduce cutter wear and damage probability, improve cutter use efficiency, reduce time consumed by a shield machine due to cutter replacement and stop of advancing, shorten a construction period, reduce construction cost, and further realize reduction of construction cost and improvement of construction efficiency of tunnel engineering construction. The application solves the problem of the conventional shield cutter head construction in the composite stratum with the upper soft and the lower hard, the fracture zone and the full-face hard rock cooperation, the serious cutter wear, the high damage rate and the influence on the construction period.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shield construction, in particular to a method for reducing costs and increasing efficiency of cutter of cutter head in shield construction of composite stratum. BACKGROUND

[0002] In some cross-sea channel engineering construction sections, they belong to typical composite stratum of upper soft and lower hard, fracture zone and hard rock of full section cooperation. The construction in such stratum is easy to cause deformation of shield cutter ring, and in severe cases, it will lead to fracture of cutter ring, causing uneven stress of cutter head and affecting the stability of shield machine propulsion.

[0003] For such composite stratum, a 15.55m diameter radial plate type composite cutter is usually used, which is assembled with 1 piece of normal pressure replacement overbreak cutter, 12 pieces of 17 inch normal pressure replacement cutter, 66 pieces of 19 inch normal pressure replacement cutter, 12 pieces of peripheral shovel cutter, 52 pieces of normal pressure replacement scraper, and 146 pieces of ordinary scraper. When the shield is propelled, the cutter head speed is controlled at 1.5r / min, and the torque is less than 5000kNm. For different stratum structures, the bubble chamber pressure is adjusted in time, and when the rock hardness is large, the penetration degree should be appropriately reduced, and the torque limit value and cutter head speed should be increased.

[0004] Because the excavation surface is mostly composed of granite, the hardness is large, and the cutter wear is serious. When the cutter head starting torque is too large, it will also cause cutter eccentric wear. Due to the complex and variable geological conditions, when the excavation surface suddenly becomes hard or the cutter collides with hard objects, it will cause local overload of the cutter ring, causing the cutter ring to break, the cutter damage rate to be high, the cutter fastener to frequently break, the cutter replacement time to be long, the cost to be high, and the total construction period and total cost to be affected.

[0005] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the background of the present application and should not be regarded as an acknowledgment or any form of suggestion that this information forms prior art that is publicly known. SUMMARY

[0006] In order to overcome the defects of the prior art, a method for reducing costs and increasing efficiency of cutter of cutter head in shield construction of composite stratum is provided to solve the problems of serious cutter wear and high damage rate in the construction of composite stratum of upper soft and lower hard, fracture zone and hard rock of full section cooperation using conventional shield cutter head.

[0007] In order to achieve the above purpose, a method for reducing costs and increasing efficiency of cutter of cutter head in shield construction of composite stratum is provided, comprising the following steps:

[0008] The application provides a radial composite cutter head and a cutter, wherein the cutter installed on the radial composite cutter head comprises a thickened hob, a spade and a wear-resistant alloy scraper, the cutter is installed on the radial composite cutter head through a front cutter barrel before shield construction, and the hardness of the cutter ring of the cutter head gradually decreases from the outer ring to the inner ring of the cutter head.

[0009] Anti-collision baffles are arranged on opposite sides of the cutter respectively, the anti-collision baffles are fixed on the cutter head, and the anti-collision baffles on the opposite sides of the cutter are arranged along the circumferential direction of the cutter head.

[0010] The cutter seat is hardfaced with a wear-resistant layer.

[0011] During the shield construction, when the shield machine passes through a soft and hard uneven stratum and the rock hardness is 40-90 MPa, the cutter head is replaced with a cutter ring with a hardness of HRC55-HRC58 and a blade width of 20-24 mm; when the shield machine passes through a fractured stratum and the rock hardness is 30-60 MPa, the cutter head is replaced with a cutter ring with a hardness of HRC55 and a blade width of 22 mm; and when the shield machine passes through a full-face hard rock stratum and the rock hardness is 50-110 MPa, the cutter head is replaced with a cutter ring with a hardness of HRC57 and a blade width of 20 mm.

[0012] During the advancing of the shield machine, the cutter head is alternately used in forward and reverse directions, the bubble chamber pressure of the shield machine is reduced when the ground settlement meets the design requirements, and the wear of the cutter is reduced.

[0013] Further, the wear-resistant layer is formed by tungsten carbide or high-chromium hardfacing welding rods.

[0014] Further, when the cutter head is alternately used in forward and reverse directions, the cutting lengths of the cutting tools in the forward and reverse directions of the cutter head are equal.

[0015] The application has the advantages that the method for reducing the cost and increasing the efficiency of the cutter of the shield construction cutter head for composite strata can effectively reduce the wear and damage of the cutter, improve the use efficiency of the cutter, reduce the time consumed by the shield machine due to the replacement of the cutter, shorten the construction period, reduce the construction cost, and further reduce the construction cost and improve the construction efficiency of the tunnel construction. DETAILED DESCRIPTION

[0016] The application will be further described in detail below with reference to the embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, and are not a limitation on the application.

[0017] It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict. The application will be described in detail below with reference to the embodiments.

[0018] The application provides a method for reducing costs and increasing efficiency of a cutter of a shield construction cutter head in a composite stratum, comprising the following steps:

[0019] S1: providing a radial plate type composite cutter head and cutters, the cutters installed on the composite cutter head comprising thickened rollers, spades and wear-resistant alloy scrapers, the cutters being installed on the radial plate type composite cutter head through a front-mounted cutter cylinder before shield construction, and the hardness of the cutter ring of the cutter head gradually decreasing from the outer ring of the cutter head to the inner ring of the cutter head.

[0020] Specifically, in the embodiment, in order to stably realize the advancement of the shield machine in the typical composite stratum with soft upper and hard lower and fracture zone and full-face hard rock, a radial plate type composite cutter head with a diameter of 15.55 m is adopted. The radial plate type composite cutter head is assembled with one normal-pressure replacement overbreak cutter, twelve normal-pressure replacement 17-inch rollers, sixty-six normal-pressure replacement 19-inch rollers, twelve peripheral spades, fifty-two normal-pressure replacement scrapers and one hundred and forty-six ordinary scrapers.

[0021] In the embodiment, the cutter ring gradient adopts the form of inner soft and outer hard, the hardness of the outer ring of the cutter head and the toughness of the inner ring are improved, and the wear of the outer ring of the cutter and the impact resistance of the inner ring are reduced.

[0022] The fastener of the front-mounted cutter cylinder is between the cutter and the excavation surface, the force of mutual extrusion of the cutter and the rock cannot be transmitted to the fastener, and then the fastener can be prevented from being broken.

[0023] The fastener of the front-mounted cutter cylinder is between the cutter and the excavation surface, when the cutter is excessively worn and the cutter cylinder is damaged, the cutter fastener is easily worn and broken to be invalid, the cutter ring falls off to the front end of the cutter head, the rotation monitoring and wear pressure relief working conditions need to be carefully observed, and the accident is prevented.

[0024] In the embodiment, the rolling adopts thickened rollers. For the hard alloy cutter, the hardness is high and the toughness is low, impact fracture is the main failure form, the blade position bears severe impact to cause the failure of the cutter, and the thickened blade and cutter body can improve the strength and wear resistance of the roller.

[0025] Increasing the thickness of the blade and the cutter body can improve the toughness of the cutter, but due to the widening of the blade, the cutting capacity is reduced, the wear of the cutter is aggravated, and the relationship between the toughness and the cutting capacity of the cutter should be well grasped.

[0026] In the embodiment, the cutting cutter on the blade adopts wear-resistant alloy blocks to enhance the strength and wear resistance of the cutter in the composite hard rock stratum.

[0027] S2: anti-collision baffles are arranged on opposite sides of the cutter respectively, the anti-collision baffles are fixedly arranged on the cutter head, and the anti-collision baffles on the opposite sides of the cutter are arranged in the circumferential direction of the cutter head.

[0028] In the embodiment, the anti-collision baffle is used to bear the impact of large-diameter rocks, reduce the direct impact of large-diameter rocks on the cutter, avoid the direct impact of rocks on the cutter, and thus prevent the damage of the cutter.

[0029] S3: hardfacing a wear-resistant layer on the cutter seat.

[0030] As a preferred embodiment, the wear-resistant layer is formed by tungsten carbide or high-chromium hardfacing electrode. Specifically, the hardfacing wear-resistant material can adopt tungsten carbide or high-chromium hardfacing electrode to improve the wear resistance.

[0031] S4: during the shield construction process, when the shield machine passes through the uneven soft and hard stratum and the rock hardness is 40 MPa-90 MPa, the cutter head is replaced with a cutter ring with a hardness of HRC55-HRC58 and a blade width of 20 mm-24 mm, when the shield machine passes through the fractured zone stratum and the rock hardness is 30 MPa-60 MPa, the cutter head is replaced with a cutter ring with a hardness of HRC55 and a blade width of 22 mm, and when the shield machine passes through the full-face hard rock stratum and the rock hardness is 50 MPa-110 MPa, the cutter head is replaced with a cutter ring with a hardness of HRC57 and a blade width of 20 mm.

[0032] S5: during the advancing process of the shield machine, the cutter head is alternately used in forward and reverse directions, and when the ground settlement meets the design requirements, the bubble chamber pressure of the shield machine is reduced to reduce the wear of the cutter.

[0033] The cutter head speed is controlled to be 1.5 r / min during the advancing process, and the torque is less than 5000 kNm. For different stratum structures, the bubble chamber pressure is adjusted in time,

[0034] The cutter wear is proportional to the number of cutter head revolutions and inversely proportional to the advancing speed. Reducing the cutter head speed and increasing the cutter penetration can reduce the cutter wear, thereby increasing the advancing distance and improving the efficiency of the cutter.

[0035] The shield cutters are usually symmetrically arranged, and the forward and reverse rotation of the cutter head is alternately used to avoid the large difference in the wear of adjacent cutters, fully utilize the cutting capacity of the cutters, and simultaneously have a certain deviation correction effect on the shield body posture.

[0036] When the forward and reverse rotation of the cutter head is alternately used, the cutting lengths of the cutting tools in the forward and reverse directions of the cutter head are equal.

[0037] When the bubble chamber pressure setting value is high, the cutting resistance of the cutter is increased, and the wear of the cutter is aggravated. Under the premise that the ground settlement meets the design requirements, the bubble chamber pressure is appropriately reduced to reduce the wear of the cutter and improve the durability of the cutter.

[0038] The method for reducing cost and increasing efficiency of a shield construction cutter of a composite stratum can effectively reduce cutter wear and damage probability, improve cutter use efficiency, reduce time consumed by a shield machine due to cutter replacement to stop advancing, shorten a construction period, reduce construction cost, and further realize reduction of construction cost and improvement of construction efficiency of tunnel engineering construction.

[0039] The above description is merely the preferred embodiments of the present application and the description of the technical principles used. It should be understood by those skilled in the art that the inventive scope involved in the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by any combinations of the above technical features or equivalent features without departing from the inventive concept. For example, the above features and the technical features disclosed in the present application (but not limited to) with similar functions are replaced with each other to form technical solutions.

Claims

1. A method for reducing costs and increasing efficiency of a cutter of a shield construction cutter head in a composite ground, characterized in that, The method comprises the following steps: A radial plate composite cutter head and cutters are provided, the cutters installed on the radial plate composite cutter head include thickened milling cutters, spade cutters and wear-resistant alloy scrapers, the cutters are installed on the radial plate composite cutter head through a front cutter barrel before shield construction, the hardness of a cutter ring of the radial plate composite cutter head gradually decreases from an outer ring of the radial plate composite cutter head to an inner ring of the radial plate composite cutter head; Anti-collision baffles are arranged on opposite sides of the cutters respectively, the anti-collision baffles are fixed on the radial plate composite cutter head, and the anti-collision baffles on the opposite sides of the cutters are arranged along a circumferential direction of the radial plate composite cutter head; A wear-resistant layer is built up on a cutter seat of the cutters; During the shield construction, when the shield machine passes through a soft and hard uneven stratum and the rock hardness is 40 MPa to 90 MPa, the radial plate composite cutter head is replaced with a cutter ring with a hardness of HRC55 to HRC58 and a blade width of 20 mm to 24 mm, when the shield machine passes through a fractured zone stratum and the rock hardness is 30 MPa to 60 MPa, the radial plate composite cutter head is replaced with a cutter ring with a hardness of HRC55 and a blade width of 22 mm, and when the shield machine passes through a full-face hard rock stratum and the rock hardness is 50 MPa to 110 MPa, the radial plate composite cutter head is replaced with a cutter ring with a hardness of HRC57 and a blade width of 20 mm; During the advancing of the shield machine, the radial plate composite cutter head is alternately used in forward and reverse rotation, when the ground settlement meets the design requirements, the bubble chamber pressure of the shield machine is reduced, and the wear of the cutters is reduced.

2. The method of reducing the cost and increasing the efficiency of the shield tunneling cutter bit of the composite ground according to claim 1, characterized in that, The wear-resistant layer is formed by tungsten carbide or high-chromium build-up welding rods.

3. The method of reducing the cost and increasing the efficiency of the shield tunneling cutter bit of the composite ground according to claim 1, characterized in that, When the radial plate composite cutter head is alternately used in forward and reverse rotation, the cutting lengths of the cutting tools in the forward and reverse directions of the radial plate composite cutter head are equal.