CN115030734B - Cutter head and cutter configuration method for shield cutting of large-diameter reinforced concrete pile foundation - Google Patents

Abstract

The invention relates to a cutter head and cutter configuration method for shield cutting of a large-diameter reinforced concrete pile foundation, which comprises the following steps: three-zone knife configuration on the plane: the three-zone cutter is divided into a central zone, a main grinding zone and a main damage zone from inside to outside; the central area is provided with a central duplex tearing knife, the main grinding area is provided with a front tearing knife, and the main damage area is provided with a hob and a welding type tearing knife; the three-layer knife is arranged in height: the three-layer cutter is divided into a main cutting layer, an auxiliary cutting layer and a scraping layer from high to low; the main cutting layer comprises a main tearing knife and a hobbing cutter, the main tearing knife comprises a center duplex tearing knife and a front tearing knife, the knife height is H1, the auxiliary cutting layer comprises an auxiliary tearing knife, namely a welding type tearing knife, the knife height is H2, the scraping layer comprises a scraper, the knife height is H3, and H1 is more than H2 and more than H3. The invention can meet the requirement that the shield cuts the large-diameter reinforced concrete pile foundation, simultaneously improves the pile cutting efficiency and reduces the construction cost.

Description

Cutter head and cutter configuration method for shield cutting of large-diameter reinforced concrete pile foundation

Technical Field

The invention belongs to the technical field of shield construction, particularly relates to a shield cutting reinforced concrete pile foundation technology, and particularly relates to a cutter head and cutter configuration method for shield cutting of a large-diameter reinforced concrete pile foundation.

Background

With the rapid development of subway networks in China, the situation of conflict with the pile foundation of the existing building (structure) is increasing in the construction process of the urban shield tunnel. The traditional treatment method mostly adopts modes of pile body side penetration, pile foundation underpinning, pile body pull-out and the like to avoid piles, and has the disadvantages of high construction cost, long construction period, large environmental influence and the like. Therefore, the existing pile body is directly cut and broken through improving the configuration of the shield cutter, the flexible selection and adjustment of the line are realized, and meanwhile, the obvious benefits are brought to the aspects of cost control, environmental protection and the like.

The soft flow plastic stratum has the characteristics of high sticky particle content, high water content, high compressibility, low water permeability, low bearing capacity and the like, and the risk of blocking a cabin by a mud cake is easily generated, so the shield construction of the soft flow plastic stratum mostly adopts a small panel spoke type cutter head and a central pipe column supporting structure, and the shield cutter is mainly configured by a scraper. The shield pile cutting needs to consider whether the integral rigidity and the structural form of the cutter head and the cutter can meet the pile cutting requirement, and the damage effect of the cutter on the reinforcing steel bars and the concrete is ensured. Therefore, the research on the shield cutter configuration is very important in combination with the soft flow plastic stratum pile cutting working condition.

Cutter wearing and tearing can produce when cutter cutting reinforced concrete pile foundation, along with the increase of cutter orbit radius, cutter wearing and tearing degree often is the exponential increase trend. In order to ensure subsequent normal tunneling operation, particularly in soft soil strata and soft plastic-flowing strata, a preset reinforcing area and other modes are usually adopted in engineering to open a bin and change a tool, along with obvious economic cost and personnel operation risk; if the number of tools on the same path line is increased, the wear of the tools is reduced, but the cost of tool arrangement is increased.

In the existing pile cutting case, shell cutters and tearing cutters are mainly used for cutting reinforced concrete pile foundations. On the basis of the original cutter head and cutter configuration of the Suzhou subway No. 2 shield, 49 shell cutters are additionally welded, and 214 cutters are configured together, so that 14 pile foundations with the diameters of 1.0 to 1.2m are continuously cut by a left line and a right line, and the Guangji bridge pile group is successfully crossed; 49 large shell cutters and 40 welding type advanced cutters are arranged on the No. 2 line shield of the Hangzhou subway, 6 reinforced concrete pile foundations are cut, and the maximum pile diameter is 1m; the Ningbo subway No. 3 wire is formed by welding 49 shells, 37 cutting blades and 9 peripheral blades, cutting pile body steel bars and concrete, and cutting 26 pile foundations with diameters of 377mm in an accumulated mode.

The cutter configuration of the above case realizes that the shield cuts through the reinforced concrete pile foundation, but still has the following defects: firstly, the track radiuses are different, the abrasion degrees of cutters are different, cutter discs are divided according to the functions and the abrasion degrees of the cutters, and the cutter spacing and the arrangement cost are controlled; secondly, the traditional shield cutter head is provided with a plurality of single type cutters, such as a full-disc tearing cutter or a full-disc hobbing cutter, and the advantages of the hobbing cutter and the tearing cutter are exerted according to the characteristics of the stratum, so that the cutter head cutters can be flexibly configured.

Therefore, in view of the above problems, it is important to provide a cutter head and cutter tool arrangement method which can meet the pile cutting requirements of engineering and control the construction cost.

Disclosure of Invention

In order to solve the problems, the invention provides a cutter head cutter configuration method for cutting a large-diameter reinforced concrete pile foundation by a shield based on the Shaoxing subway No. 2 line pile cutting project, which is particularly suitable for the shield in a soft plastic stratum to cut the large-diameter reinforced concrete pile foundation, so that the shield can meet the requirement of cutting the reinforced concrete pile foundation, the construction period is shortened, and the construction cost is reduced.

The invention is realized by the following steps:

the invention firstly provides a cutter head and cutter configuration method for shield cutting of a large-diameter reinforced concrete pile foundation, which comprises the following steps:

the three-zone cutter configuration is carried out on the plane of the cutter head, and comprises the following steps: (1) Dividing the cutter on the plane of the cutter head into a central area, a main grinding area and a main loss area from inside to outside; (2) Performing 'three-zone cutter' configuration according to zone division, wherein slag is discharged from a 'central zone', a central duplex tearing cutter is configured, a 'main grinding zone' pile cutting is configured, a front tearing cutter is configured, a 'main damage zone' gauge protection is configured, and a hobbing cutter and a welding type tearing cutter are configured; (3) setting the knife spacing according to the configuration of the three-zone knife;

the 'three-layer cutter' configuration is carried out on the height of the cutter, and comprises the following steps: (1) According to the main factors affecting cutter abrasion and shield tunneling, namely pile body steel bars, the height of the cutter is divided into layers from high to low, and the layers are divided into a main cutting layer, an auxiliary cutting layer and a scraping layer; (2) And performing cutter height difference configuration on the 'three-layer cutter' according to layering division, wherein the 'main cutting layer' cutter comprises a main tearing cutter and a hob, the main tearing cutter comprises a center duplex tearing cutter and a front tearing cutter, the cutter height is H1, the 'auxiliary cutting layer' cutter comprises an auxiliary tearing cutter, namely a welding type tearing cutter, the cutter height is H2, the 'scraping layer' cutter comprises a scraper, the cutter height is H3, and H1 & gtH 2 & gtH 3.

In some embodiments, in the partition division of the cutter on the cutter plane, the track radius of the central area meets 0 < R < 0.3R, the track radius of the main grinding area meets 0.3R < R < 0.85R, the track radius of the main damage area meets 0.85R < R < R, and R is the cutter radius.

In some embodiments, in the knife spacing setting according to the configuration of the three-zone knife, the knife spacing of the knife in the central zone is set to be 90mm ≦ L1 ≦ 95mm, the knife spacing of the knife in the main grinding zone is set to be 80mm ≦ L2 ≦ 85mm, and the knife spacing of the knife in the main damage zone is set to be 25mm ≦ L3 ≦ 80mm.

In some embodiments, in the configuration of the cutter height difference of the three-layer cutter according to the layered division, the cutter height difference H1-H3 of the main tearing cutter and the scraper is set to meet the condition that the scraper scrapes the concrete of the steel bar protection layer before the main tearing cutter cuts the steel bars.

In some embodiments, in the step height difference configuration of the three-layer cutter according to the layering division, the cutter height difference H2-H3 of the auxiliary tearing cutter and the scraper is set to be not less than the diameter of the steel bar.

In some embodiments, the configuring of the knife height difference of the three-layer knife according to the layering division further includes setting the height of the hob knife to be consistent with the height of the main tearing knife.

The invention provides a cutter head cutter structure for shield cutting of a large-diameter reinforced concrete pile foundation, which comprises a cutter head and cutters arranged on the cutter head, wherein the cutter head comprises a central area, a main grinding area and a main damage area from inside to outside on a plane, the central area is used for discharging slag and is provided with a central duplex tearing cutter, the main grinding area is used for cutting piles and is provided with a front tearing cutter, the diameter of the main damage area is kept, and a hob and a welding type tearing cutter are arranged; the cutter comprises a main cutting layer, an auxiliary cutting layer and a scraping layer from high to low in height, wherein the main cutting layer cutter comprises a main tearing cutter and a hob, the main tearing cutter comprises a center duplex tearing cutter and a front face tearing cutter, the cutter height is H1, the auxiliary cutting layer cutter comprises an auxiliary tearing cutter, namely a welding type tearing cutter, the cutter height is H2, the scraping layer cutter comprises a scraper, the cutter height is H3, and H1 is more than H2 and more than H3.

In some embodiments, the "primary cutting layer" cutter height H1 is 160mm, the "secondary cutting layer" cutter height H2 is 140mm, and the "skiving layer" cutter height H3 is 115mm.

In some embodiments, the hob in the "primary cutting layer" is co-orbitally arranged with the welded tear knife in the "secondary cutting layer".

The invention also provides a method for shield cutting of a large-diameter reinforced concrete pile foundation by using the cutter head and cutter structure of the previous aspect, which comprises the following steps:

s10: rotationally propelling the shield cutter head;

s20: the 'main cutting layer' cutter firstly contacts the soil body of the tunnel face and the pile body, and the main tearing cutter and the hob cutter cut into the concrete of the reinforcing steel bar protection layer;

s30: the shield cutter head continues to rotate and advance, and when the cutting depth reaches the cutter height difference H1-H3 between the main tearing cutter and the scraper, the scraper scrapes the concrete of the reinforcing steel bar protective layer;

s40: the scraper continuously peels off the concrete of the reinforcing steel bar protective layer along with the continuous rotation and propulsion of the cutter head, the main tearing knife and the hob cutter reach the reinforcing steel bar, the main tearing knife and the hob cutter cut off the reinforcing steel bar, and the scraper does not contact the reinforcing steel bar;

s50: if the main tearing knife is damaged, the auxiliary tearing knife participates in pile cutting in a successive compensation mode, the auxiliary tearing knife cuts off the reinforcing steel bars, and the scraper still does not touch the reinforcing steel bars or just touches the reinforcing steel bars;

s60: the complete long reinforcing bar of pile body is cut into the nipple joint reinforcing bar by tearing the sword, and along with the continuation rotation of blade disc, the scraper is close the nipple joint reinforcing bar gradually, progressively peels off the pile body with the nipple joint reinforcing bar, discharges along with the dregs together.

Compared with the prior art, the invention has the beneficial effects that:

1. the three-section cutter arrangement concept of 'central area deslagging, main grinding area pile cutting and main damage area diameter protection' is provided, the grinding and damage of the cutters are controlled, and the arrangement cost and the pile cutting efficiency of the cutters are balanced.

2. The three-layer cutter arrangement concept of 'one main cutter, one auxiliary cutter and one scraping' is provided, the main cutter, the auxiliary cutter and the scraper are configured in a layering mode, and the pile cutting capability, the pile cutting efficiency and the safety storage of the shield are improved.

3. The pile cutting cutterhead is configured in a combined mode of a tearing cutter and a hobbing cutter, the excavation diameter is controlled by fully utilizing a rolling concrete breaking mechanism of the hobbing cutter, the effective cutting of a reinforced concrete pile body is realized by utilizing a concrete breaking and rib cutting mechanism of the tearing cutter, and the pile cutting capability of the shield is comprehensively improved.

4. Through the knife height difference of rational configuration main rip sword and scraper to and the knife height difference of assisting rip sword and scraper, ensure to cut off the reinforcing bar at stake in-process main rip sword, assist the rip sword and provide safe deposit, the reinforcing bar protective layer concrete is scraped to the scraper, and the scraper can not touch the reinforcing bar before cutting off the reinforcing bar, avoids the scraper to damage.

5. The lengths of the cut and scraped steel bars and the size of the concrete slag sample are moderate, the expectation is met, the discharge of a screw machine is easy, and the phenomenon of blocking is avoided.

6. Compared with the existing pile cutting case, the number of the tearing cutters required for pile cutting is obviously reduced, the pile cutting cost is reduced, and the cutter abrasion degree meets the expectation.

It should be understood that the implementation of any embodiment of the present invention is not intended to achieve or achieve many or all of the above-described benefits simultaneously.

It should be understood that the statements herein reciting aspects are not intended to limit the critical or essential features of any embodiment of the invention, nor are they intended to limit the scope of the invention. Other features of the present invention will become apparent from the following description.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so that those skilled in the art can understand and read the present invention, and do not limit the conditions for implementing the present invention, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the functions and purposes of the present invention, shall fall within the scope covered by the technical contents disclosed in the present invention.

FIG. 1 illustrates a schematic view of a "three zone knife" arrangement of a preferred embodiment;

FIG. 2 schematically illustrates a "triple layer knife" arrangement in accordance with a preferred embodiment;

FIG. 3 is a diagram illustrating an actual arrangement of a shield cutterhead cutter;

FIG. 4 (a) is a schematic diagram illustrating an exemplary center duplex tear-off knife configuration;

FIG. 4 (b) is a schematic view illustrating a front tearing knife configuration;

FIG. 4 (c) is a schematic view illustrating a welded type tearing knife;

FIG. 4 (d) is a schematic view illustrating a hob construction;

FIG. 5 illustrates a tool wear statistical diagram;

FIG. 6 illustrates a tool breakage statistical schematic;

FIG. 7 is a diagram illustrating an example of a cut concrete slag sample;

FIG. 8 (a) is a diagram illustrating an object of a steel bar cutting mark in an early stage of pile cutting;

FIG. 8 (b) is a physical diagram illustrating the cut marks of the steel bars in the middle and later stages of pile cutting;

fig. 8 (c) exemplarily shows a real object diagram of the tendon cutting result.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the present invention is described in further detail below with reference to the embodiments and the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.

In the description of the present invention, the terms "comprises/comprising," "consists of ...components" or any other variations thereof are intended to cover non-exclusive inclusions, such that a product, device, process or method comprising a list of elements does not include only those elements but may include other elements not expressly listed if necessary or inherent to such product, device, process or method. Without further limitation, an element defined by the phrases "comprising/including" ... "comprising ...and ... "comprises;" does not exclude the presence of additional like elements in a product, device, process, or method comprising the element.

It is to be understood that, unless otherwise expressly specified or limited, the terms "disposed," "mounted," "connected," "secured," and the like are intended to be inclusive and mean, for example, that any suitable arrangement may be utilized and that any suitable connection, whether permanent or removable, or integral, may be utilized; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

It will be further understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," "center," and the like are used in an orientation or positional relationship illustrated in the drawings for convenience in describing and simplifying the invention, and do not indicate or imply that the device, component, or structure being referred to must have a particular orientation, be constructed in a particular orientation, or be operated in a particular manner, and should not be construed as limiting the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

The following describes the implementation of the present invention in detail with reference to preferred embodiments.

The invention provides a cutter head and cutter configuration method for shield cutting of a large-diameter reinforced concrete pile foundation, which is particularly suitable for a soft flow plastic stratum shield and aims at the large-diameter reinforced concrete pile foundation. The large diameter, i.e. the pile base diameter, is generally not less than 800mm, for example in the range of 800mm to 1500mm.

The cutter head cutter configuration method comprises the meaning of two layers, namely a three-layer cutter configuration on a plane and a three-layer cutter configuration on the height. The details are set forth in the detailed description below with reference to the specific figures.

The first layer, the "three zone knife" configuration on the plane, see fig. 1, specifically is:

firstly, the cutter is partitioned on the plane of a cutter head, and the cutter is partitioned into a central area, a main grinding area and a main loss area from inside to outside; the "three zone knife" provides the zoning criteria for the tearing knife, and the corresponding knife spacing L1, L2, L3 settings.

Next, referring to fig. 2 and 3, the configuration of "three zone knife" is performed according to the partition division:

(1) The "center area" knife is a center duplex tearing knife, as shown in fig. 4 (a). In order to realize pile cutting of a soft flow plastic stratum, the design of a central fishtail cutter is cancelled, and a central duplex tearing cutter with the height consistent with that of a main tearing cutter is selected, so that the stress of a pile body is uniform during pile cutting, and the stress concentration and the large deformation of the pile body are reduced. The 'central area' is added with foam and water injection ports which play a role in discharging concrete slag blocks and clay so as to prevent center mud cakes.

The 'central area' mainly plays a role in discharging slag, so that a central fishtail knife is omitted, and mud cakes in the central area are prevented. Although the "center area" is mainly based on slag discharge, it is obvious that the central duplex tearing knife also plays a role of cutting piles, and 7 pieces of alloy are arranged at the knife edge.

(2) The 'main grinding area' is mainly used for cutting piles, and is provided with a front tearing knife, as shown in fig. 4 (b), the rigidity and the concrete cutting and reinforcing capacity of the front tearing knife are superior to those of a center duplex tearing knife.

The main grinding area mainly plays a role of pile cutting, and the tool tip of the front tearing tool is provided with 9 pieces of alloy.

The invention does not arrange a hob cutter in the main grinding area, and because the hob cutter easily causes displacement of the pile body and is not beneficial to directly cutting off the pile body, the front tearing cutter is selected as the cutter of the main grinding area.

(3) The main damage area is mainly protected, the cutters are a hobbing cutter and a welding type tearing cutter, as shown in fig. 4 (c) and 4 (d), the welding type tearing cutter and the hobbing cutter share the same track line, the hobbing cutter is inserted with a single edge, 42 pieces of alloy are inserted into the edge, and 7 pieces of alloy are inserted into the welding type tearing cutter. The 'main damage area' is provided with a hob with higher tool rigidity and impact resistance, the hob mainly grinds the pile, alloy teeth are embedded to improve the concrete cutting and rib cutting capability of the hob, and meanwhile, a welding type tearing knife is arranged on a line with the same track as the hob, so that the safety storage of the 'main damage area' is improved, and the loss of the concrete cutting and rib cutting and diameter preserving capability due to chord grinding of the hob is prevented.

It should be noted that the "main damage area" is mainly the gauge protection, but not only the gauge protection, and since the linear velocity of the "main damage area" is relatively large, the shield machine is easily damaged, and once damaged, the shield machine will be clamped, and the section diameter cannot be guaranteed.

It should be noted that, for the welding type tearing knife, because the number of knife seats of a cutterhead is fixed, and the extra knife can only be welded on the small panel of the cutterhead when the extra knife is added, the welding type tearing knife mentioned in the invention is additionally added with the tearing knife and is welded on the small panel.

And finally, setting the knife interval according to the configuration of the three-zone knife. In particular, as described in detail below.

The second layer, configured with "three layers of knives" in height, with continued reference to fig. 2 and 3, specifically includes:

firstly, the height of the cutter is divided into layers according to the pile body steel bar which is a main factor influencing the cutter abrasion and the shield tunneling.

The three-layer cutter is divided into a main cutting layer, an auxiliary cutting layer and a scraping layer from high to low, and the three-layer cutter provides a cutter height difference arrangement scheme of the cutter. The scheme of 'three layers of cutters' considers that pile body steel bars are the main reasons influencing cutter abrasion and shield tunneling, so that cutter height difference is set, a multi-layer cutter scheme is formed in the height, the cutter height difference is respectively used in time nodes and space, and the cutter height difference is matched with the cutter height difference to jointly cut piles, so that the damage amount of a single cutter can be reduced, and the pile cutting efficiency can be improved.

Secondly, under the condition that the cutter height difference is determined to be divided in layers, cutter height difference configuration is carried out on a 'three-layer cutter' according to the layer division, wherein the 'main cutting layer' cutter comprises a main tearing cutter and a hobbing cutter, the main tearing cutter comprises a center duplex tearing cutter and a front tearing cutter, the cutter height is H1, the 'auxiliary cutting layer' cutter comprises an auxiliary tearing cutter, namely a welding type tearing cutter, the cutter height is H2, the 'scraping layer' cutter comprises a scraper, the cutter height is H3, and H1 & gtH 2 & gtH 3.

The main tearing knives in the main cutting layer are mainly distributed in the central area and the main grinding area and are used as the cutters which are firstly contacted with the pile body, so that the main tearing knives are cut into the concrete of the reinforcing steel bar protective layer in advance before cutting the reinforcing steel bars, the heights of the main tearing knives are consistent, uniform concrete breaking and uniform reinforcing steel bar cutting are realized, the damage amount of a single cutter is reduced, and the continuous pile cutting operation of the shield is facilitated.

The hobbing cutters in the 'main cutting layer' are mainly distributed in a main damage area and have the same height as that of a main tearing cutter, the edge of the main damage area is provided with the embedded hobbing cutters which have higher rigidity and concrete cutting and rib cutting capacity, and the main damage area mainly depends on the hobbing cutters to participate in the first batch of pile grinding so as to ensure the excavation and the diameter protection. The main damage area adopts hobbing cutter excavation gauge protection, no longer sets up main tearing sword, avoids because the too big tearing sword of edge linear velocity leads to tearing the sword to hit badly, because the hobbing cutter has higher rigidity and shock resistance.

The 'auxiliary cutting layer' cutter is mainly distributed in a main damage area and is mainly an auxiliary tearing cutter, and although excavation and diameter protection are completed by a hob in the main damage area, the hob is easy to generate chord grinding in a soft plastic stratum and lose pile cutting capability, so that the auxiliary tearing cutter is arranged and safe storage is provided for shield pile cutting. When the auxiliary tearing cutter is used for cutting piles, the height difference between the auxiliary tearing cutter and the scraper cutter is required to be not smaller than the diameter (for example, 25 mm) of the steel bar, and the scraper is prevented from collapsing after being stressed.

The pile cutting cutterhead is configured in a combined mode of the tearing cutter and the hobbing cutter, the excavation diameter is controlled by fully utilizing a rolling concrete breaking mechanism of the hobbing cutter, the effective cutting of a reinforced concrete pile body is realized by utilizing a concrete breaking and rib cutting mechanism of the tearing cutter, and the pile cutting capability of the shield is comprehensively improved.

The scrapers of the scraping layer are responsible for scraping concrete ridges and unbroken reinforcing steel bars during pile cutting. To the scraper, the knife height difference that needs to set up main sword and scraper of tearing satisfies the main sword before tearing the sword cut the muscle that scrapes reinforcing bar protective layer concrete, reduces the muscle degree of difficulty of cutting.

In some embodiments, in the partition division of the cutter on the cutter plane, according to the analysis of statistical results, the track radius R of the central area is within 0.3R, the track radius R of the main grinding area is more than 0.3R and less than or equal to 0.85R, the track radius of the main damage area is more than 0.85R and less than or equal to R, and R is the cutter radius. For example, for a common 6980 shield machine, as shown in fig. 5 and 6, by counting tool wear and tool breakage, each square in the graph represents a statistical value of a tool, and fitting a logarithmic value point to obtain a fitted curve, two obvious slope turning points on the curve are obtained, wherein the two obvious slope turning points are respectively at 1058mm and 2985mm, which indicate that the tool wear and the tool breakage are suddenly changed at the track radius, so that a "central area" track radius R is less than or equal to 1058mm, a "main wear area" track radius 1058mm is less than or equal to 2985mm, and a "main wear area" track radius 2985mm is less than or equal to 3490mm. The specific zoning division is related to construction parameters, for example, the cutter head rotates too fast, and a cutter with a small radius may also have a high linear speed due to the fast rotation, and finally crack is generated, but the specific zoning division generally conforms to the division. The invention obtains the partition division of the cutter on the cutter plane through the statistical analysis of the pile cutting effect and the wear data in the actual subway shield project, provides reference for the partition division and the configuration of cutters of other projects, has universality, is also suitable for shield cutters with different diameters, and has an error within an allowable range.

In some embodiments, in the knife spacing setting according to the configuration of the three-zone knife, the wear degree of the knife in the central zone is low due to the small track radius, and the center duplex tearing knife with relatively high knife spacing and high overall rigidity is arranged, so that the arrangement cost of the knife is reduced. According to engineering experience and considering the characteristic of the soft flow plastic stratum, the cutter spacing of the cutter in the central area is set to be more than or equal to 90mm and less than or equal to L1 and less than or equal to 95mm.

The distance between the cutters in the main grinding area is smaller than that in the central area, and the arrangement density of the cutters is improved, so that the damage of the pile body is increased. According to engineering experience and consideration of the soft flow plastic stratum characteristics, the cutter spacing of the cutter in the main grinding area is set to be 80 mm-L2-85 mm.

The distance between the cutters in the main damage area is smaller than that in the main grinding area, the density of the cutters is increased to improve the pile cutting and diameter protecting capability, and the damage of the cutters in cutting concrete and cutting ribs is reduced. According to engineering experience and consideration of the soft flow plastic stratum characteristics, the cutter spacing of the cutter in the main damage area is set to be more than or equal to 25mm and less than or equal to L3 and less than or equal to 80mm.

In some embodiments, in the step height difference configuration of the three-layer cutter according to the layered division, the cutter height differences H1-H3 of the main tearing cutter and the scraper are set to meet the condition that the scraper scrapes the concrete of the steel bar protection layer before the main tearing cutter cuts the steel bars. When cutting the stake, the scraper is responsible for scraping concrete spine and not cracked reinforcing bar, for example pile foundation reinforcing bar protective layer thickness 75mm, needs to set up the sword difference in height of main rip sword and scraper and satisfies scraper scraping reinforcing bar protective layer before main rip sword muscle to reduce the muscle degree of difficulty of cutting.

In some embodiments, in the step height difference configuration of the three-layer cutter according to the layering division, the cutter height difference H2-H3 of the auxiliary tearing cutter and the scraper is not less than the diameter of the steel bar. When assisting the tearing sword and cutting the stake, need consider with scraper knife difference in height should not be less than reinforcing bar diameter (25 mm), cut the muscle with assisting the tearing sword promptly, prevent that the scraper from contacting the reinforcing bar in advance, avoid its atress after collapsing.

Referring to fig. 2 and 3, the cutter head tool structure for shield cutting of large-diameter reinforced concrete pile foundations of the invention is as follows:

the cutter head comprises a central area, a main grinding area and a main damage area from inside to outside on a plane, wherein the central area is used for discharging slag, a central fishtail cutter is omitted, a central duplex tearing cutter is configured, a pile is cut in the main grinding area, a front tearing cutter is configured, the diameter of the main damage area is protected, and a single-edge inserted hob and a welding type tearing cutter are configured;

the cutter comprises a main cutting layer, an auxiliary cutting layer and a scraping layer from high to low in height, wherein the main cutting layer cutter comprises a main tearing cutter and a hob, the main tearing cutter comprises a center duplex tearing cutter and a front face tearing cutter, the cutter height is H1, the auxiliary cutting layer cutter comprises an auxiliary tearing cutter, namely a welding type tearing cutter, the cutter height is H2, the scraping layer cutter comprises a scraper, the cutter height is H3, and H1 & gtH 2 & gtH 3.

In some embodiments, the "primary cutting layer" cutter height H1 is 160mm, the "secondary cutting layer" cutter height H2 is 140mm, the "skiving layer" cutter height H3 is 115mm, and the hob height is 160mm consistent with the "primary cutting layer" cutter height.

The method for shield pile cutting by using the cutter head cutter structure comprises the following steps:

s10: rotationally propelling the shield cutter head;

s20: the 'main cutting layer' cutter firstly contacts the soil body of the tunnel face and the pile body, and the main tearing cutter and the hob cutter cut into the concrete of the reinforcing steel bar protection layer;

s30: the shield cutter head continues to rotate and advance, and when the cutting depth reaches the cutter height difference H1-H3 between the main tearing cutter and the scraper, the scraper scrapes concrete on the reinforcing steel bar protective layer;

s40: the scraper continuously peels off the concrete of the reinforcing steel bar protective layer along with the continuous rotation and propulsion of the cutter head, the main tearing knife and the hob knife cut off the reinforcing steel bars, and the scraper does not touch the reinforcing steel bars;

s50: when the main tearing knife and/or the hobbing cutter are damaged and the auxiliary tearing knife is high, the auxiliary tearing knife is supplemented to participate in pile cutting, the auxiliary tearing knife cuts off the reinforcing steel bars, and the scraper is not contacted with the reinforcing steel bars or just contacted with the reinforcing steel bars;

s60: the complete long reinforcing bar of pile body is cut into the nipple joint reinforcing bar by tearing the sword, and along with the continuation rotation of blade disc, the scraper is close the nipple joint reinforcing bar gradually, progressively peels off the pile body with the nipple joint reinforcing bar, discharges along with the dregs together.

In the whole pile cutting process, the working process of the hob and the working process of the main tearing knife are the same, the heights of the main tearing knife and the hob are both 160mm, the alloy height of the main tearing knife and the height of the cutter teeth of the hob are also the same, for example, the heights of the main tearing knife and the cutter teeth of the hob are both 3cm, when the main tearing knife is damaged to 140, the auxiliary tearing knife participates in working, and when the hob is damaged to 140, the auxiliary tearing knife also participates in working.

Engineering application:

the Shaoxing subway No. 2 line shield is used for a certain section, the engineering geological condition is a soft flow plastic stratum, 22 large-diameter reinforced concrete pile foundations are cut on the right line, wherein 8 engineering piles with the diameter of 1000mm, 14 guard piles with the diameter of 800mm are arranged in the shield. The main reinforcement of the pile body is 18 HRB400 type screw-thread steels with the diameter of 25mm, the stirrup is smooth steel reinforcement with the diameter of 10mm, and the concrete grade is C30. The tunnel excavation radius R =3490mm. The cutter is arranged in a soft plastic stratum shield to cut a large-diameter reinforced concrete pile foundation.

"three-zone knife" cutter arrangement:

(1) The radius R of a control track in the central area is less than or equal to 1058mm, the knife interval is controlled to be L1=90mm, and 12 pairs of central duplex tearing knives are arranged together.

(2) The radius of a control track in the main grinding area is more than 1058 and less than or equal to 2985mm, the distance between knives is controlled to be L2=80mm, and 24 pairs of front tearing knives are arranged.

(3) The radius of a control track in the 'main damage area' is more than 2985 and less than or equal to 3490mm, the distance between knives is controlled to be L3 between 27 and 79mm, and 12 handles of the welding type tearing knife are configured.

"three layer knife" cutter arrangement:

(1) In the main cutting layer, the main tearing knife is a front tearing knife and a center duplex tearing knife, the height of the main tearing knife is set to be 160mm, the main tearing knife firstly contacts the soil body of the tunnel face and the pile body, and the distance between the main tearing knife and the scraper is 45mm, so that the reinforcing steel bar protective layer is broken in advance before the reinforcing steel bar is cut.

(2) In the auxiliary cutting layer, the auxiliary tearing knife is a welding type tearing knife, the knife height is set to be 140mm, the distance between the auxiliary tearing knife and the scraper is 25mm, and safety storage is provided for shield pile cutting.

(3) In the scraping layer, the height of the scraper is set to be 115mm, and the function of scraping soil and reinforced concrete is achieved.

(4) The height of the hob cutter is set to be consistent with that of the main tearing cutter, and is 160mm.

Pile cutting effect:

(1) By means of the cutter arrangement method of the three-zone cutter and the three-layer cutter, 47 large-diameter reinforced concrete pile foundations in a certain interval of the No. 2 line of the Shaoxing subway are smoothly achieved, a cutter head is assembled with 12 double tearing cutters (R is less than or equal to 1058 mm), 24 front tearing cutters (1058 is greater than R and less than or equal to 2985 mm), 12 welded tearing cutters (2985 is greater than R and less than or equal to 3490 mm), 12 single-edge inserted hob cutters (2985 is greater than R and less than or equal to 3490 mm), 48 tearing cutters are matched, and 12 edge inserted hob cutters are arranged.

(2) As can be seen from the abrasion and damage results of the cutter shown in fig. 5 and 6, in the pile cutting process, the abrasion of the cutter surface in the "central area" is mainly the abrasion, i.e., the thinning of the overlay welding layer on the cutter surface, the initial overlay welding thickness of the cutter surface is 3mm, and the average overlay welding residual amount in the "central area" is 2.29mm; the main grinding area cutter also mainly takes abrasion as main part, a small amount of damage exists, part of alloy at the cutter point of the cutter is broken, the average surfacing residual amount is 1.94mm, and the average damage amount is 5.81mm; the tool in the main damage area mainly damages, and simultaneously has obvious abrasion, the alloy of the tool point of part of the tool is totally collapsed, the average build-up welding residual amount is 1.24mm, and the average damage amount is 23.11mm. Based on the partition standard of the three-area cutter, the shield pile cutting task is completed, and the abrasion degree of the cutter accords with expectation.

(3) Based on the principle of arranging three-zone cutters and three-layer cutters, the tearing cutters have good cutting effect on the reinforced concrete pile body.

The concrete slag sample is shown in fig. 7, and the diameter distribution of the concrete slag sample is counted as follows: 5 percent of D which is less than 9.5mm, 11 percent of D which is less than 16mm and is more than 9.5mm, 10 percent of D which is more than 16mm and is less than 19mm, 7 percent of D which is more than 19mm and is less than 26.5mm, 9 percent of D which is more than 26.5mm and is less than 31.5mm, 58 percent of D which is more than 31.5mm, 42 percent of slag blocks with the grain diameter of less than 31.5mm, and no slag blocks with the grain diameter of more than 10cm are found.

The steel bar shearing trace is obvious, as shown in fig. 8 (a), 8 (b) and 8 (c), fig. 8 (a) shows the steel bar shear mark when the pile cutting is just started, a plurality of shear marks are applied to a short steel bar section in an initial state, fig. 8 (b) shows the steel bar shear mark cut to the middle and later stages, as can be seen from the figure, the steel bar shear mark is further deepened along with the continuous pile cutting, the steel bar is mainly sheared and pulled to be damaged, the shearing angle is 11.2-12.0 degrees, the average shearing depth of a shearing opening is about 8mm, the average distance of the shearing opening is 79.24mm, the lengths of the broken steel bars are distributed in a range of 43-66cm, and as shown in fig. 8 (c), the arrangement of a three-section cutter and a three-layer cutter is reasonable.

The cutter head cutter arrangement scheme is successfully applied to Shaoxing subway pile cutting engineering, has a good construction effect, smoothly achieves the engineering target of continuously cutting and penetrating 47 large-diameter reinforced concrete pile foundations by a soft flow plastic stratum shield, and is worthy of popularization and reference for related engineering.

It will be readily appreciated by those skilled in the art that the above-described preferred embodiments may be freely combined, superimposed, without conflict.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (5)

1. A cutter head and cutter configuration method for shield cutting of a large-diameter reinforced concrete pile foundation is characterized by comprising the following steps:

the three-zone cutter configuration is carried out on the plane of the cutter head, and comprises the following steps:

(1) The cutter is divided into a center area, a main grinding area and a main damage area from inside to outside, the track radius of the center area is more than 0 and less than or equal to 0.3R, the track radius of the main grinding area is more than 0.3R and less than or equal to 0.85R, the track radius of the main damage area is more than or equal to 0.85R and less than or equal to R, and R is the radius of the cutter;

(2) Configuring three-area cutters according to partition division, wherein slag is discharged from a central area, center duplex tearing cutters are configured, a main grinding area pile cutting area is configured, a front tearing cutter is configured, a main loss area diameter is protected, a hob and a welding type tearing cutter are configured, and the hob and the welding type tearing cutter are arranged in the same track line;

(3) Setting the distance between the cutters according to the configuration of three cutters, wherein the distance between the cutters in the central area is set to be more than or equal to 90mm and less than or equal to L1 and less than or equal to 95mm, the distance between the cutters in the main grinding area is set to be more than or equal to 80mm and less than or equal to L2 and less than or equal to 85mm, and the distance between the cutters in the main damage area is set to be more than or equal to 25mm and less than or equal to L3 and less than or equal to 80mm;

performing a "three layer knife" configuration at the knife height, comprising:

(1) According to the main factors affecting cutter abrasion and shield tunneling, namely pile body steel bars, the height of the cutter is divided into layers from high to low, and the layers are divided into a main cutting layer, an auxiliary cutting layer and a scraping layer;

(2) Carrying out cutter height difference configuration on a 'three-layer cutter' according to layered division, wherein the 'main cutting layer' cutter comprises a main tearing cutter and a hob, the main tearing cutter comprises a center duplex tearing cutter and a front tearing cutter, the cutter height is H1, the 'auxiliary cutting layer' cutter comprises an auxiliary tearing cutter, namely a welding type tearing cutter, the cutter height is H2, the 'scraping layer' cutter comprises a scraper, the cutter height is H3, H1 is more than H2 and is more than H3, and the hob height is consistent with the cutter height of the main tearing cutter; and the cutter height difference H1-H3 of the main tearing cutter and the scraper meets the requirement that the scraper scrapes concrete on the protective layer of the steel bar before the main tearing cutter cuts the steel bar, and the cutter height difference H2-H3 of the auxiliary tearing cutter and the scraper is not smaller than the diameter of the steel bar.

2. The utility model provides a shield constructs blade disc cutter structure of cutting major diameter reinforced concrete pile foundation, includes the blade disc and arranges cutter on the blade disc, its characterized in that:

the cutter head comprises a central area, a main grinding area and a main damage area from inside to outside on a plane, wherein the central area is used for discharging slag and is provided with a central duplex tearing cutter, the main grinding area is used for cutting piles and is provided with a front tearing cutter, the diameter of the main damage area is protected and is provided with a hob and a welding type tearing cutter, and the hob and the welding type tearing cutter are arranged in the same track line; the track radius of the central area is more than 0 and less than or equal to 0.3R, the track radius of the main grinding area is more than 0.3R and less than or equal to 0.85R, the track radius of the main damage area is more than 0.85R and less than or equal to R, and R is the radius of the cutter head; the cutter spacing of the cutter in the central area is more than or equal to 90mm and less than or equal to L1 and less than or equal to 95mm, the cutter spacing of the cutter in the main grinding area is more than or equal to 80mm and less than or equal to L2 and less than or equal to 85mm, and the cutter spacing of the cutter in the main damage area is more than or equal to 25mm and less than or equal to L3 and less than or equal to 80mm;

the cutter comprises a main cutting layer, an auxiliary cutting layer and a scraping layer from high to low in height, wherein the main cutting layer cutter comprises a main tearing cutter and a hob, the main tearing cutter comprises a center duplex tearing cutter and a front face tearing cutter, the cutter height is H1, the auxiliary cutting layer cutter comprises an auxiliary tearing cutter, namely a welding type tearing cutter, the cutter height is H2, the scraping layer cutter comprises a scraper, the cutter height is H3, H1 is more than H2 and more than H3, and the cutter height of the hob is consistent with that of the main tearing cutter; and the height difference H1-H3 between the main tearing knife and the scraper meets the requirement that the scraper scrapes the concrete of the protective layer of the steel bar before the main tearing knife cuts the steel bar, and the height difference H2-H3 between the auxiliary tearing knife and the scraper is not less than the diameter of the steel bar.

3. The cutter head structure according to claim 2, wherein:

the cutter height H1 of the 'main cutting layer' is 160mm, the cutter height H2 of the 'auxiliary cutting layer' is 140mm, and the cutter height H3 of the 'scraping layer' is 115mm.

4. The cutter head structure according to claim 2, wherein:

and the hob in the main cutting layer and the welded tearing knife in the auxiliary cutting layer are arranged in the same track line.

5. A method of shield-cutting a large-diameter reinforced concrete pile foundation using the cutterhead cutter structure of any one of claims 2 to 4, comprising:

s10: rotationally propelling the shield cutter head;

s20: the 'main cutting layer' cutter firstly contacts the soil body of the tunnel face and the pile body, and the main tearing cutter and the hob cutter cut into the concrete of the reinforcing steel bar protection layer;

s30: the shield cutter head continues to rotate and advance, and when the cutting depth reaches the cutter height difference H1-H3 between the main tearing cutter and the scraper, the scraper scrapes concrete on the reinforcing steel bar protective layer;

s40: the scraper continuously peels off the concrete of the reinforcing steel bar protective layer along with the continuous rotation and propulsion of the cutter head, the main tearing knife and the hob knife cut off the reinforcing steel bars, and the scraper does not touch the reinforcing steel bars;

s50: if the main tearing knife is damaged, the auxiliary tearing knife participates in pile cutting in a successive compensation mode, the auxiliary tearing knife cuts off the reinforcing steel bars, and the scraper still does not touch the reinforcing steel bars or just touches the reinforcing steel bars;

s60: the complete long reinforcing bar of pile body is cut into the nipple joint reinforcing bar by tearing the sword, and along with the continuation rotation of blade disc, the scraper is close the nipple joint reinforcing bar gradually, progressively peels off the pile body with the nipple joint reinforcing bar, discharges along with the dregs together.

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