Shield tail grout stopping system for shield tunneling in full-face hard rock strata, its installation method and construction method

Abstract

The present invention relates to a tail seal grouting system for a shield tunneling in a full-face hard rock formation, and an installation method and a construction method thereof. The tail seal grouting system includes: an abrasion-resistant grouting plate brush structure, including an inner grouting plate brush and an outer grouting plate brush. The inner grouting plate brush is fixedly connected to a first part of the shield tail through a first connecting mechanism, and the outer grouting plate brush is fixedly connected to a second part of the shield tail through a second connecting mechanism. The first part is different from the second part, and both the inner grouting plate brush and the outer grouting plate brush are open towards the tunneling rear, with the inner grouting plate brush abutting against the segment and the outer grouting plate brush abutting against the surrounding rock; an airbag structure, which has a sealing surface facing the tunneling rear, and in the inflated state, the inner area of the sealing surface is in close contact with the segment, and the outer area is in close contact with the surrounding rock. The present invention can ensure the sealing of the post-grouting behind the segment wall and prevent slurry leakage to the shield shell or even into the front soil chamber.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, in particular to the technology of backfilling the excavation gap, and specifically to the tail seal slurry system for shield tunneling in full-section hard rock strata, its installation method and construction method. Background Art

[0002] Shields (shield machines) generally include two types: earth pressure balance shields and slurry balance shields, and are a kind of machinery used for tunneling in soft soil or loose rock mass tunnels, as Figure 1 shown. Its main characteristics are as follows:

[0003] (1) In order to discharge slag, the cutter head needs to have a certain opening ratio;

[0004] (2) There is a closed soil chamber that can apply a stable pressure to the heading face during the excavation process;

[0005] (3) There is a closed and stable slag discharge system. For example, the earth pressure balance shield discharges slag through a screw conveyor, while the slurry balance shield discharges slag through a slurry pressure pipeline;

[0006] (4) There is a closed tail seal brush structure. The tail seal brush can be in full contact with the outer wall of the segment to ensure complete sealing and prevent the synchronous grouting slurry from leaking into the tunnel interior.

[0007] When a shield tunnels in full-section hard rock strata, the following problems are faced:

[0008] Shields are usually used for excavating soil. However, with the gradual development of engineering construction, the strata in some coastal cities in China, such as Qingdao, Dalian, Shenzhen and other regions, show very complex characteristics such as soil-rock composite, uneven hardness, etc. There are a large number of stratum fracture zones, and even the results of geological exploration cannot fully show the distribution of these complex strata. This leads to the situation that when a shield is tunneling in soft strata (soil or strongly weathered rock stratum), it suddenly encounters a full-section hard rock stratum section. Or although a small section of hard rock stratum is detected by geological exploration (according to the geological conditions in Qingdao area, generally there is a 50 - 100m hard rock section in a 1000m interval), due to construction period or cost issues, it is impossible to replace the TBM (or other construction methods for hard rock strata) for this small section of hard rock stratum at this time. Therefore, the shield has to continue to tunnel through this hard rock stratum.

[0009] The grouting process of shields (including both earth pressure balance shields and slurry balance shields) in full-section hard rock strata is as Figure 2As shown in the figure, due to the existence of the tail seal brush, the slurry for synchronous grouting will not flow into the tunnel interior along with the inner gap (the gap between the tail shield and the segment). However, there is a lack of sealing equipment between the tail shield and the surrounding rock, which makes it easy for the slurry to flow into the shield shell or even into the soil chamber from the outer gap (the gap between the tail shield and the surrounding rock). Generally speaking, the following problems will occur:

[0010] (1) The slurry for synchronous grouting will flow into the gap between the shield shell and the surrounding rock, posing a risk of jamming the shield shell after coagulation and causing the shield machine to be trapped;

[0011] (2) In a more serious situation, the slurry will flow forward into the soil chamber through the gap between the shield shell and the surrounding rock, posing a risk of jamming the cutter head and cutters after coagulation;

[0012] (3) Although there are also excavation gaps when the shield machine is in soft soil strata, part of the soil will collapse after excavation, resulting in a reduction in the gap. Moreover, after grouting the soft soil strata, the slurry will also infiltrate into the soil layer to play a role in reinforcement. Therefore, it will not flow into areas such as the shield shell in a large area. However, in hard rock strata, there is neither collapse nor the effect of slurry infiltration. Therefore, it is very easy to cause the risk of slurry leakage;

[0013] (4) Since the slurry will not infiltrate into the hard rock strata, the segment will be completely wrapped by the slurry, resulting in a more serious phenomenon of segment floating than in soft soil strata. Subsequently, it is very easy to cause serious tunnel structure quality problems such as segment misalignment, damage, and gasket dislocation.

[0014] (5) Due to concerns about problems such as slurry leakage and slurry leakage, sometimes the on-site construction will abandon the synchronous grouting work and change it to radial grouting through the reserved holes in the segment after the segment has been withdrawn from the tail shield by 3 to 5 rings. This will cause more problems. For example, these rings of segments withdrawn from the tail shield are only supported by the friction between the jacks and adjacent segments and bolt connections at this time, and there is no support force in the vertical direction, so it is very easy to cause segment misalignment, damage, and even affect the tunnel safety. At the same time, since there is no need to build pressure in the soil chamber in the full-section rock strata (excavating with an empty chamber), the jacking force is very low, increasing the hidden danger of segment instability. Summary of the Invention

[0015] In view of the deficiencies of the prior art, the main purpose of the present invention is to provide a tail seal slurry stopping system for a shield machine during tunneling in a full-section hard rock stratum, its installation method, and construction method to solve one or more problems in the prior art.

[0016] The technical solution of the present invention is as follows:

[0017] The present invention first provides a tail seal grouting system for a shield tunneling in a full-face hard rock formation, comprising: a wear-resistant grouting plate brush structure, which is integrally annular and is fixedly connected to the shield tail in a shape consistent with the shield tail, including an inner grouting plate brush and an outer grouting plate brush. The inner grouting plate brush is fixedly connected to a first part of the shield tail through a first connecting mechanism, and the outer grouting plate brush is fixedly connected to a second part of the shield tail through a second connecting mechanism. The first part is different from the second part, and both the inner grouting plate brush and the outer grouting plate brush are open towards the tunneling rear. The inner grouting plate brush abuts against the segment, and the outer grouting plate brush abuts against the surrounding rock; an airbag structure, which is integrally annular and is arranged between the inner grouting plate brush and the outer grouting plate brush in a shape consistent with the shield tail. The airbag structure has a sealing surface facing the tunneling rear, and in the inflated state, the inner area of the sealing surface is in close contact with the segment, and the outer area is in close contact with the surrounding rock.

[0018] The present invention also provides an installation method for the aforementioned tail seal grouting system, comprising: S1: Bolt hole drilling, drilling bolt holes in the shield tail of the shield; S2: Base plate installation, first installing the base plate at the position of the synchronous grouting pipe, and then extending and connecting it to both sides respectively with this base plate as the center until the entire ring of the shield tail is covered; S3: Inner grouting plate brush installation, installing wire plate brushes, inner protection plates and outer protection plates. The wire plate brushes are arranged side by side, and the inner protection plates and the outer protection plates respectively adopt a three-layer overlapping and lapping method, and finally fastening them with tightening bolts; S4: Outer grouting plate brush installation, first installing the grouting and grouting-stop plate brush at the position of the synchronous grouting pipe, and then gradually lapping and assembling the conventional grouting-stop plate brushes to both sides with this grouting and grouting-stop plate brush as the center until the entire ring of the shield tail is covered; S5: Filling with sealing grease, after the installation of the entire wear-resistant grouting plate brush structure is completed, after the shield machine is hoisted into the well as a whole and assembled, filling sealing grease in the part of the wire plate brushes; S6: Extension of the synchronous grouting pipe, carrying out the extension operation of the synchronous grouting pipe in the well, and fixedly connecting the extended synchronous grouting pipe to the shield tail by full welding; S7: Airbag installation, positioning and installing the entire ring of airbag between the inner grouting plate brush and the outer grouting plate brush, welding and connecting it to the grouting pipe channel, and bolt-connecting it to the fixed steel plate; S8: Installation of the outer-wrapped wear-resistant elastic wire mesh, laying the outer-wrapped wear-resistant elastic wire mesh on the sealing surface of the airbag, and connecting and fixing both ends to the base plate; S9: Debugging of the air compressor and instruments, checking the airtightness of the airbag, checking the connection condition, opening degree and elasticity of the sealing plate, and the installation is completed.

[0019] The present invention further provides a construction method according to the aforementioned tail seal grouting system, including: S1: The shield tunneling forward, and after the tunneling is completed, segment assembly is carried out; S2: Set the air pressure and inflate the airbag; S3: Inspect the air pressure stability of the airbag. If it is unstable, check the airbag and reinflate it until the air pressure of the airbag is stable; S4: After the air pressure of the airbag is stable, carry out synchronous grouting / segment hole grouting; S5: After synchronous grouting / segment hole grouting, check whether the air pressure is stable until the entire ring of segments is filled / grouted; S6: Exhaust the airbag, and the shield continues to tunnel forward, preparing for the assembly and grouting prevention construction of the next ring of segments.

[0020] The beneficial effects of the present invention compared with the prior art are as follows: The present invention designs a tail seal grouting system for shield tunneling in full-section hard rock strata, its installation method and construction method to ensure the plugging of post-grouting behind the segments and prevent grout leakage into the shield shell or even the front soil chamber. The following specific effects are expected to be achieved:

[0021] On the basis of not changing the original tail seal brush structure, a wire brush structure is directly added to the end of the tail seal, and the inside of the wire brush is filled with sealing grease, which can not only play a sealing role but also protect the original tail seal brush. The protective plates on both the inner and outer sides are overlapped and arranged, which can seal the entire wire brush structure, ensure that the grease is not easily leaked, and at the same time can also play the role of stabilizing the entire structure.

[0022] The specially designed base plate is completely bolt-connected to the tail seal, without any special treatment for the existing tail seal. The connection method is simple and convenient, and it also facilitates its replaceability.

[0023] The outer grouting prevention plate brush and the inner grouting prevention plate brush are independently installed at different positions, so that when it is necessary to independently replace the outer plate brush, only the connecting bolts need to be opened.

[0024] The outer grouting prevention plate brush is specially designed and processed at the position of the synchronous grouting pipe of the shield, which not only ensures that the synchronous grouting process is not affected but also can play a sealing effect.

[0025] The material of the grouting prevention plate brush is 65Mn spring steel, which has certain elasticity and wear resistance. At the same time, the airbag is also embedded with wear-resistant steel wires to ensure that it is not easily worn and damaged during construction.

[0026] It should be understood that the implementation of any embodiment of the present invention does not mean that multiple or all of the above beneficial effects need to be simultaneously achieved or reached. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are merely exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0028] The structures, ratios, sizes, etc. shown are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the conditions under which the present invention can be implemented. Therefore, they do not have technical substance significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

[0029] Figure 1 It is a schematic diagram of the conventional shield composition structure, where (a) is a slurry balance shield and (b) is an earth pressure balance shield;

[0030] Figure 2 It is a schematic diagram of the grouting situation of the earth pressure balance shield in hard rock strata;

[0031] Figure 3 It is a schematic diagram of the overall structure of the wear-resistant grout stop brush;

[0032] Figure 4 It is a schematic diagram of the base plate structure, where (a) is a side view and (b) is a plan view;

[0033] Figure 5 It is a schematic diagram of the inner grout stop brush structure, where (a) is a side view and (b) is a plan view;

[0034] Figure 6 It is a schematic diagram of the composition plane of the inner grout stop brush, where (a) is the wire plate brushes arranged side by side, (b) is the lap joint of the inner protection plate, and (c) is the lap joint of the outer protection plate;

[0035] Figure 7 It is a schematic diagram of the outer grout stop brush structure, where (a) is a side view, (b) is a single-piece plan view, and (c) is a three-piece lap joint plan view;

[0036] Figure 8 It is a schematic diagram of the grout passing and stopping brush structure, where (a) is a side view, (b) is a disassembled plan view, and (c) is an assembled plan view;

[0037] Figure 9 It is a schematic diagram of the special treatment of the airbag, where (a) is a side view and (b) is a front view;

[0038] Figure 10Schematic diagram of wear-resistant steel wire mesh structure;

[0039] Figure 11 Schematic diagram of airbag structure, where (a) is before inflation and (b) is after inflation;

[0040] Figure 12 Schematic diagram of the installation process of the grout stopping system;

[0041] Figure 13 Schematic diagram of the construction process using the grout stopping system;

[0042] Figure 14 Schematic diagram of the cross-section of the shield, where (a) is before inflation and (b) is after inflation;

[0043] Figure 15 Physical diagram of the on-site installation of the grout stopping system;

[0044] Figure 16 Effect diagram of the grout stopping plate system installed before the shield launching of a certain project, where (a) is the top view and (b) is the side view;

[0045] Figure 17 Diagram of the wear condition of the grout stopping plate received after the shield tunneling 544.5m of a certain project, where (a) is the left side, (b) is the right side, (c) is the top, and (d) is the bottom. Specific implementation mode

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer and more understandable, the embodiments of the present invention will be further described in detail below in combination with the embodiments and the drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not limit the present invention.

[0047] In the present invention, unless otherwise clearly specified and defined, terms such as "installation", "connection", "connection", "fixation", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] It should be understood that the terms "comprising / including", "consisting of" or any other variants are intended to cover non-exclusive inclusion, such that a product, device, process or method comprising a series of elements not only includes those elements but also, when necessary, other elements not expressly listed, or elements inherent to such product, device, process or method. Without further limitation, elements defined by the statement "comprising / including..." or "consisting of" do not exclude the presence of additional identical elements in the product, device, process or method comprising the said elements.

[0049] It also needs to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation to the present invention.

[0050] Based on the problems existing in the prior art, the present invention designs a grout stopping system that can be directly installed at the shield tail of a shield tunneling machine, and mainly considers the following design principles:

[0051] (1) Installation feasibility and applicability. The structure should be universal, that is, it can be directly installed on most shield tails, and at the same time, it should not damage or change the existing shield tail structure too much, affecting the use of the equipment of the shield itself.

[0052] (2) The ability to seal the gap between the shield shell and the surrounding rock. When synchronous grouting is carried out, the grout is likely to flow from the gap between the shield tail and the surrounding rock to the shield shell, causing the shield shell to be locked. If the amount of grout leakage is too large, it is also easy to flow to the position of the cutterhead in the front, seriously affecting problems such as the rock breaking of the rolling cutter. In addition, for the original shield tail brush, although it can ensure that the grout does not flow into the tunnel from the internal gap between the segment and the shield tail, the replacement of the shield tail brush and the excessive consumption of sealing grease have always been construction problems. Therefore, it is necessary to be able to protect the original shield tail brush and reduce the grease consumption.

[0053] (3) Wear resistance. This point is specifically for the outer sealing equipment, because the outer sealing equipment will directly contact the surrounding rock and generate contact friction with the surrounding rock during the shield tunneling process.

[0054] (4) Flexibility. This point is for the inner sealing equipment, because the inner sealing equipment directly contacts the outer wall of the segment, and excessive stiffness will cause damage to the segment. Therefore, it should have a certain degree of flexibility and deformability to ensure that the sealing equipment is in flexible contact with the outer wall of the segment.

[0055] (5) Inspectability and replaceability. Due to the uncontrollability of the harsh geological conditions during shield tunneling, it is necessary to ensure the integrity of the plugging equipment can be inspected under convenient conditions, and at the same time, its replaceability must be ensured to facilitate timely replacement in case of severe wear of the plugging equipment. Therefore, in order to facilitate manual replacement, the weight of each single piece should not be too large.

[0056] In view of the above existing problems and design requirements, the present invention designs a tail seal grouting system for a shield tunneling in a full-face hard rock formation. Taking a shield with a diameter of 6m as an example, the implementation of the present invention will be described in detail in combination with the preferred embodiments.

[0057] As Figure 3 shown, a tail seal grouting system for a shield tunneling in a full-face hard rock formation provided by the present invention is integrally installed on the existing shield tail 1, and is composed of a wear-resistant grout seal brush structure 2, an airbag structure 3 and the corresponding connecting bolts of each component.

[0058] Combining Figure 4 , the wear-resistant grout seal brush structure 2 is integrally connected and fixed to the shield tail 1 in a ring shape consistent with the shield tail 1, and includes an inner grout seal brush 21 and an outer grout seal brush 22. The inner grout seal brush 21 is connected and fixed to the first part of the shield tail 1 through the first connecting mechanism, and the outer grout seal brush 22 is connected and fixed to the second part of the shield tail 1 through the second connecting mechanism. The first part is different from the second part, and the inner grout seal brush 21 and the outer grout seal brush 22 are open towards the rear of tunneling. The inner grout seal brush 21 abuts against the segment, and the outer grout seal brush 22 abuts against the surrounding rock.

[0059] Since the outer grout seal brush 22 is in direct contact with the surrounding rock, it is more likely to be worn compared to the situation where the inner grout seal brush 21 is in contact with the segment. In the present invention, the inner grout seal brush and the outer grout seal brush are connected to different positions of the shield tail by different connecting mechanisms. When it is desired to replace the outer brush, only the second connecting mechanism of the outer grout seal brush 22 needs to be opened separately.

[0060] The airbag structure 3 is integrally arranged in a ring shape consistent with the shield tail between the inner grout seal brush 21 and the outer grout seal brush 22. The airbag structure 3 has a plugging surface facing the rear of tunneling, and in the inflated state, the inner area of the plugging surface is in close contact with the segment, and the outer area is in close contact with the surrounding rock.

[0061] In the present invention, the following terms should be generally understood:

[0062] The so-called inner area refers to the inner area of the ring shape of the airbag structure 3, which is a local area close to the segment side; the so-called outer area refers to the outer area of the ring shape of the airbag structure 3, which is a local area close to the surrounding rock side.

[0063] The so-called "front" should be understood as the direction of shield tunneling, and the "rear" is the opposite direction of shield tunneling.

[0064] With the grout stopping system of the present invention, it is directly installed on the existing shield tail. The inner grout stopping plate brush 21 abuts against and fits the segment to achieve the sealing of the inner side of the shield tail (i.e., the gap between the shield tail and the outer wall of the segment), and the outer grout stopping plate brush 22 abuts against and fits the surrounding rock to achieve the sealing of the outer side of the shield tail (i.e., the gap between the shield tail and the surrounding rock). At the same time, with the help of air inflation sealing, in this way, the gap behind the segment can be completely blocked to ensure the sealing of the grouting behind the segment and prevent the grout from leaking into the shield shell or even the front soil chamber.

[0065] In some embodiments, continue to refer to Figure 3 , bolt holes are temporarily opened at the edge of the shield tail 1, and the wear-resistant grout stopping plate brush structure 1 is fixed to the shield tail 1 through the base plate 4 and the fixing bolts 5. The base plate 4 is a strip-shaped straight plate or an arc-shaped plate structure with a certain curvature. The edge shape corresponds to the edge of the shield tail 1. For example, it is designed as a rabbet type and can be fixed by fitting with the edge of the shield tail 1. A plurality of bolt holes are opened on it. By using the fixing bolts 5 to pass through the bolt holes on the base plate 4 and the bolt holes temporarily opened on the edge of the shield tail 1, the base plate 4 is connected and fixed to the shield tail 1. The wear-resistant sealing plate is connected to the shield tail by bolts. The bolts are easy to disassemble. When the sealing plate brush is severely worn, it can be directly replaced by disassembling the bolts instead of cutting it off like welding. Whether it is installation or replacement after wear, it is more convenient; compared with heat treatment methods such as welding, welding is prone to cause deformation of the shield tail due to heat. After the shield tail is deformed (i.e., becomes non-circular), it will seriously affect the quality of segment assembly. Bolt connection will not damage the structure of the shield tail and will not cause problems such as shield tail deformation due to heat treatment such as welding.

[0066] Design of the base plate:

[0067] As Figure 4 shown, in some embodiments, the base plate 4 has a connecting section 41 facing the tunneling front. A first bolt hole (not marked in the figure, that is, the bolt hole for passing the fixing bolt 5) is opened on the connecting section 41, and the connecting section 41 is connected and fixed to the shield tail 1 by the fixing bolt 5 passing through the first bolt hole.

[0068] In some embodiments, a second bolt hole (not marked in the figure, that is, the bolt hole for passing the tightening bolt 42) is also opened on the connecting section 41, and the first part is the position on the connecting section 41 relatively close to the shield tail. The first connecting mechanism is the tightening bolt 42, and the inner grout stopping plate brush 21 is connected and fixed to the connecting section 41 by the tightening bolt 42 passing through the second bolt hole.

[0069] Specifically, the connecting section 41 is formed with a protruding end and a slot portion. A first bolt hole is formed in the protruding end, and a second bolt hole is formed in the slot portion. A slot is formed inside the slot portion, and the inner grout stop brush 21 is inserted into the slot and fastened and fixed with a fastening bolt 42. By inserting the inner grout stop brush 21 into the slot and fastening and fixing it with the fastening bolt 42, the inner grout stop brush 21 is stably held on the connecting section 41 to prevent it from falling off.

[0070] Continue to refer to Figure 4 , in some embodiments, the base plate 4 has an extension section 43 facing the rear of the tunneling. A third bolt hole (not marked in the figure, that is, the bolt hole for passing through the connecting bolt 44) is formed in the extension section 43. The second part is the position on the extension section 43 relatively far from the shield tail. The second connecting mechanism is the connecting bolt 44. The outer grout stop brush 22 is connected and fixed to the extension section 43 by the connecting bolt 44 passing through the third bolt hole.

[0071] It should be noted that the extension section 43 extends obliquely towards the outside of the shield tunnel, and as a whole forms a Y shape with the inner grout stop brush 21.

[0072] Preferably, the second bolt hole is a single-row hole, the third bolt hole is a double-row hole, the connecting bolt 44 is arranged in two rows, and the outer grout stop brush 22 and the extension section 43 are fixed with two rows of bolts, which is more stable during lapping and not easy to rotate in the width direction.

[0073] Preferably, considering the feasibility of processing and production and the convenience of on-site installation, the width of the base plate 4 is designed to be 200 mm.

[0074] Design of the inner grout stop brush:

[0075] There are multiple groups of the inner grout stop brushes 21 arranged in a ring shape consistent with the shield tail. Continue to refer to Figure 5In some embodiments, the inner slurry-stopping brush 21 is composed of a wire brush 211, an inner protective plate 212, and an outer protective plate 213. The wire brush 211, the inner protective plate 212, and the outer protective plate 213 are each provided with a corresponding tightening bolt hole 214. This arrangement is advantageous in that, since the shield tail of the shield machine is equipped with a tail brush, the tail brush can also ensure that the slurry does not flow from the inner side of the tail into the tunnel. However, sometimes the tail brush may be worn or fail due to factors such as incorrect segment posture. In consideration of the above problems, the present invention does not change the original tail brush structure, but directly adds a wire brush structure to the end of the tail, and the wire brush is filled with sealing grease. This not only plays a sealing role but also protects the original tail brush from erosion by slurry, thereby increasing the service life of the tail brush and reducing the frequency of replacing the sealing grease. On the other hand, it forms an open whole with the outer slurry-stopping brush, which can support and protect the airbag when the airbag is inflated. However, since the wire brush is full of grease, it is very troublesome to replace it, and because the inner slurry-stopping brush is not seriously worn in contact with the pipe segment, it is only necessary to replace the outer one after wear. Therefore, the present invention configures the inner slurry-stopping brush and the outer slurry-stopping brush separately, and they can be disassembled and replaced independently during subsequent replacement without affecting each other. There is no need to disassemble the inner slurry-stopping brush when replacing the outer slurry-stopping brush that wears faster.

[0076] Figure 5 The plan view shows that the width of a single wire brush and the protective plates on both sides is preferably 100mm, which is half of the width of the base plate (200mm). Therefore, at least two side by side are required to cover the entire base plate. Since the wire brush is in an open state, it can only be arranged side by side, and the inner and outer protective plates are connected and arranged in an overlapping manner, as shown in the figure. Figure 6 The characteristics of this arrangement are as follows: the wire brush has a certain thickness and is in an open state, so it cannot be overlapped. However, there are protective plates on both sides of it, which can be overlapped. The advantage of this is that it can seal the entire wire brush structure to ensure that grease is not easy to leak out, and at the same time it can stabilize the entire structure.

[0077] External slurry stop brush design:

[0078] The outer slurry-stopping brushes 22 have multiple groups arranged in a ring shape consistent with the shield tail. Figure 7 In some embodiments, one end of the outer slurry-stopping brush 22 is provided with a double row of bolt holes, connected to the extension section 43 with a double row of bolts. The other end is bent inward, with the corners rounded. Preferably, the bend is 90° or approximately 90°, with the corners rounded to form arc-shaped edges. The overall structural details have the following features:

[0079] (1) It is fixed to the base plate by double-row bolts, and it is more stable during lapping and not prone to rotation in the width direction.

[0080] (2) One end of the outer side of the grout stop brush is in an arc-shaped corner. In this way, it contacts the surrounding rock surface by means of a smooth surface, aiming to reduce the friction with the surrounding rock and damage to the grout stop brush, and also reduce its wear.

[0081] As Figure 7 As shown, the width of a single grout stop brush is 100 mm, and the width of the base plate is 200 mm. Therefore, the grout stop brush is fixed to the base plate by bolts in an overlapping lapping manner. The width of a single grout stop brush is half of the base plate, so that the sealing connection can be ensured by the overlapping lapping of the grout stop brushes between each base plate, and the sealing effect of the structure is guaranteed.

[0082] Preferably, the grout stop brushes are arranged in a three-layer overlapping lapping manner, and waterproof rubber is pasted between every two layers to ensure the sealing between the grout stop brushes. The three-layer grout stop brushes are connected and fixed by bolts.

[0083] The outer grout stop brush is made of 65Mn spring steel. The 65Mn spring steel material has a certain elasticity, which is convenient for bending into a certain angle in the aforementioned bending treatment, and the 65Mn spring steel material also has a certain wear resistance to ensure the wear resistance in contact with the surrounding rock.

[0084] There are pipelines for synchronous grouting arranged at the tail of the shield. In order to prevent the grout stop brush from affecting the synchronous grouting process, the present invention makes special design and treatment at the position of the grouting pipe, as Figure 8 shown. The outer grout stop brush 22 includes a conventional grout stop brush 221 and a grout-passing grout stop brush 222. The width of a single grout-passing grout stop brush 222 is greater than that of the conventional grout stop brush 221. The grout-passing grout stop brush 222 is arranged at the position of the synchronous grouting pipe 6. The synchronous grouting pipe 6 is extended at the position of the grout-passing grout stop brush 222. The grout-passing grout stop brush 222 is provided with at least one grouting pipe channel 223 with the same aperture as the synchronous grouting pipe at the corresponding position of the synchronous grouting pipe 6. The grouting pipe channel 223 is used for passing through the extended synchronous grouting pipe 6.

[0085] Specifically, two grouting pipe channels 223 are provided. Considering the widths of the two grouting pipe channels 223 at the position of the grouting pipeline, the dimensions at the position of the grouting pipeline at the tail of different shields need to be measured on site and designed separately. As Figure 8As shown, in the present invention, the total length of the two grouting pipe channels 223 after being overlapped by two plate brushes is exactly 365 mm, meeting the construction requirements. Therefore, the overall width of a single slurry-passing and grout-stopping plate brush is designed to be 365 mm, which is formed by overlapping two special 200-mm-wide grout-stopping plate brushes and two normal 100-mm-wide grout-stopping plate brushes. The connecting side edges of the two special 200-mm-wide grout-stopping plate brushes are reserved with grouting pipe channels 223. A single grout-stopping plate brush is specially treated according to the grouting holes. By setting two channels with the same diameter as the original grouting holes of the shield at the specified positions, it not only ensures that the synchronous grouting process is not affected but also can achieve a sealing effect. The physical diagram of the entire structure is as shown in Figure 15 shown.

[0086] Airbag design:

[0087] The airbag is arranged and installed in a complete ring throughout the tail shield, and the airbag is fixed on the outer wall of the channel. In order to ensure that the synchronous grouting process and the inflation of the airbag do not conflict with each other and do not affect each other, the synchronous grouting pipe is extended and made to completely pass through the airbag. Correspondingly, slurry-passing holes 31 are reserved on the airbag corresponding to the grouting pipe channels 223, as shown in Figure 9 shown. The positions and sizes of the slurry-passing holes 31 correspond to the grouting pipe channels 223. Before leaving the factory, the airbag can be edge-sealed and sealed at the positions of the slurry-passing holes 31 to ensure the integrity and sealing performance of the airbag.

[0088] Preferably, the structural material of the airbag is rubber, and a high-pressure thick rubber airbag is made of three layers of nitrile rubber sandwiching two layers of nylon cloth, with a maximum bearing pressure of 5 bar. Before the airbag is inflated, it is protected by the inner and outer grout-stopping plate brushes. When the airbag is inflated and expanded, it closely adheres to the segment and the surrounding rock, playing a role in sealing and stopping grout.

[0089] The airbag structure 3 also has an inflation surface facing the tunneling front, and at least two groups of air inlet holes and air outlet holes with an interval not greater than 180° are arranged on the inflation surface. Two air inlet / outlet holes can also be connected to the left and right sides of the airbag, and air compressors are installed on both holes and equipped with digital display airbag pressure gauges. The digital display airbag pressure gauges can record the changes in the pressure received by the airbag at any time, including the extrusion pressure of the slurry, etc., so as to judge the grout-stopping situation of the sealing system at any time.

[0090] Since the airbag is installed in a complete ring outside the grout-stopping plate brush, it needs to be protected by the grout-stopping plate brush and also have a certain wear resistance after inflation. In some embodiments, the present invention provides an airbag protection structure 7 outside the airbag, which at least surrounds the sealing surface of the airbag structure and can stretch with the inflation and expansion of the airbag. By setting a protection structure outside the airbag, the airbag is protected to prevent accidental damage to the airbag caused by construction processes or surrounding rock debris.

[0091] As shown in Figure 3 , Figure 10As shown, in some embodiments, the airbag protection structure 7 is a wear-resistant elastic wire mesh. The wear-resistant elastic wire mesh first includes an outer-wrapped wear-resistant elastic wire mesh, which is wrapped on the sealing surface and its two ends bypass the inner and outer regions of the sealing surface and are connected and fixed to the base plate 4; see Figure 11 , the sealing side of the airbag is filled with the wear-resistant elastic wire mesh. After inflation and expansion, the wear-resistant elastic wire mesh is stretched and serves as a protective layer to directly contact the segment and the surrounding rock, avoiding direct contact between the rubber and the surrounding rock and thus wearing, playing a role in protecting the airbag.

[0092] In addition, the wear-resistant elastic wire mesh may further include an embedded wear-resistant elastic wire mesh (not shown in the figure), which is embedded in the surface layer or the interior of the airbag; in this way, part of the wire mesh is embedded in the rubber, and the wire mesh and the rubber form an integral body. For example, when the rubber is molded, the wire mesh is integrally embedded in the surface or the interior of the airbag by means of heat treatment, which can be more firmly combined with the rubber and improve the strength of the rubber airbag itself.

[0093] It should be noted that the outer-wrapped wear-resistant elastic wire mesh and the embedded wear-resistant elastic wire mesh can be two independent groups of wire meshes, or they can be a group of wire meshes. In this case, the wire mesh is a multi-layer structure, with the inner layer embedded in the rubber and the outer layer wrapped on the surface of the airbag. Of course, the wire mesh can also be a single-layer structure, with part of the wire mesh embedded in the rubber and part of it wrapped on the surface of the airbag. The present invention does not make specific restrictions on this.

[0094] It is easy to understand that when the wire mesh is wrapped or embedded, it is made into a folded and bent structure, similar to a household kitchen wire brush, so that it can stretch together when the rubber stretches.

[0095] Preferably, as Figure 10 shown, the wire mesh is connected to a fixing steel plate 71, and the fixing steel plate 71 is finally fixed to the base plate 4 by bolts.

[0096] It should be noted that both the inner and outer grout stop plate brushes of the present invention are composed of multiple groups, and the multiple groups of plate brushes are integrally connected in a ring shape consistent with the shield tail 1 and fixed to the shield tail 1 of the shield machine.

[0097] Similarly, taking the installation of the grout stop plate brush of a certain 6m-class diameter shield tail as an example, the basic installation process of the grout stop system of the present invention will be elaborated in detail below.

[0098] The installation of the base plate and the grout stop plate brush can be carried out on the ground or underground. Considering the inconvenience of underground operation, since the shield tail is in an upright state on the ground and the installation is relatively convenient, it is preferably carried out on the ground. It is necessary to lay the shield tail horizontally on the ground before the shield machine starts, and carry out the connection work of the base plate and the grout stop plate brush on the ground, while the connection of the airbag and the like needs to be carried out underground. After the entire shield machine is installed, it is installed at the starting portal. See Figure 12 , the installation process of the entire grout stop system is as follows:

[0099] (1) Sealing of the shield tail slots and drilling of bolt holes (if there are slots);

[0100] If there are shield tail slots, fill in the gaps of the shield tail slots to form a complete shield shell to ensure the integrity of the installation of the grout stop plate brush. At the same time, drill bolt holes around the shield tail.

[0101] (2) Installation of the base plate, and install the base plate to the shield tail with bolts;

[0102] First, install the base plates at the positions of the four synchronous grouting pipes, and then extend and connect them to both sides respectively with the base plates at the positions of each grouting pipe as the center until the entire ring of the shield tail is covered. If the distance at the last splicing position is not enough for one piece, consider cutting or welding.

[0103] (3) Installation of the wire brush and the protection plates on both its inner and outer sides;

[0104] The wire brushes are arranged side by side, and the two inner and outer protection plates respectively adopt the method of three - layer overlapping lap joint, and finally are fastened by tightening bolts.

[0105] (4) Installation of the outer grout stop plate brush and the fixing steel plate;

[0106] First, install the grout - passing and grout - stopping plate brushes at the positions of the four synchronous grouting pipes, and then gradually lap and assemble the ordinary 100 - mm - wide conventional grout stop plate brushes until the entire ring is covered. Finally, pay attention to tightening the bolts.

[0107] (5) Filling of sealing grease;

[0108] After the installation of the entire grout stop plate brush structure is completed, and after the shield machine is hoisted into the well as a whole and assembled, fill the wire brush part with sealing grease;

[0109] (6) First, carry out the extension work of the synchronous grouting pipes in the well. The channel and the shield tail are welded, and full welding is carried out to ensure the quality.

[0110] (7) Installation of the airbag, position and install the whole - ring airbag between the inner grout stop plate brush and the outer grout stop plate brush, weld it to the grouting pipe channel, and connect it to the fixing steel plate with bolts;

[0111] After the installation of the airbag is completed, install the outer - wrapped wear - resistant elastic wire mesh as appropriate.

[0112] (8) Debugging of the air compressor and instruments, check the airtightness of the airbag, check the connection of the sealing plate, the opening degree and elasticity, and the installation is completed.

[0113] See Figure 13 , the construction method of the shield tail grout stop system according to the present invention includes:

[0114] S1: The shield tunneling machine advances forward. After the tunneling is completed, segment erection is carried out.

[0115] S2: Set the air pressure and inflate the airbag.

[0116] S3: Check the air pressure stability of the airbag. If it is unstable, check the airbag and reinflate it until the air pressure of the airbag is stable.

[0117] S4: After the air pressure of the airbag is stable, grouting is carried out through the synchronous grouting pipeline, or radial grouting is carried out through the reserved holes in the segments.

[0118] S5: After synchronous grouting / segment hole grouting, check whether the air pressure is stable until the filling / grouting of the entire ring of segments is completed. Judge the grouting situation by the stability of the air pressure. If the air pressure finally stabilizes without decreasing, the grouting is completed.

[0119] S6: The airbag is deflated, and the shield tunneling machine continues to advance forward, preparing for the erection of the next ring of segments and the slurry stop construction.

[0120] See Figure 11 、 Figure 14 As shown, two air compressors are equipped at two positions on the left and right inside the tunnel to maintain the inflation and deflation of the airbag. Before the airbag is inflated, it is protected by the slurry stop brush on both the inner and outer sides. At this time, the airbag does not contact the surrounding rock, so the seal of the shield tail gap is only provided by the outer slurry stop brush. When the airbag is inflated and bulges, the airbag is in full contact with the surrounding rock, forming a highly sealed effect. Therefore, the inflated airbag ensures the contact seal with the surrounding rock without affecting the synchronous grouting.

[0121] Leakage inspection:

[0122] Three leakage inspection methods are recommended. The first is to check whether the rock slag of the muck truck contains slurry. This method is simple but has poor reliability because once slurry is detected in the rock slag, it means that the amount of leaked slurry has been large enough to flow into the soil chamber. The second is to record the amount of grout each time. This method is also very simple but not intuitive enough. The third method is to directly drill several holes with a diameter of 1 - 2 cm at the shield tail (a little inside the slurry stop brush), then seal the holes with ball valves, and insert a wooden stick or a thin tube that can distinguish the color of the slurry to directly check whether there is leakage.

[0123] Replacement of the slurry stop brush:

[0124] The replacement process of the slurry stop brush of the present invention is to remove 1 - 2 rings of segments at the shield tail under the condition of ensuring a full-section rock formation and stable surrounding rock. After the slurry stop brush is exposed, it can be directly replaced. If only the inner wire brush or the outer slurry stop brush needs to be replaced, the bolts can be directly disassembled; if the base plate is damaged and needs to be replaced as a whole, it can be re-welded. The entire replacement process is not cumbersome and is within the operable range.

[0125] Evaluation of the application effect of the grout stop system:

[0126] The grout stop system designed by the present invention has been applied in actual engineering on site. Before the launch of a certain earth pressure balance shield tunneling machine, the grout stop system was installed (as shown in Figure 16 ). After that, it tunnelled a total of 544.5 m until it reached the reception. When it reached the reception (as shown in Figure 17 ), it could be clearly observed that:

[0127] (1) Wear condition of the sealing plate

[0128] When the TBM reached the reception, there was no damage or peeling on both sides, the top and the bottom, indicating that the grout stop plate withstood the wear and damage of the surrounding rock over a distance of 544.5 m.

[0129] (2) Residue after the hardening of the grout could be clearly seen on the concave side of the grout stop plate (i.e., the side where the grout was blocked), and the residue at the bottom was the most obvious. This indicates that the grout stop plate played an obvious role in blocking and stopping the grout, resulting in a large area of residue of the grout.

[0130] (3) The tail seal brushes and tail seal grease were not replaced during the entire 544.5 m tunneling of the shield tunneling machine, indicating that the inner grout stop plate played an obvious protective role, withstood the loss of the tail seal grease, and also protected the tail seal brushes from damage.

[0131] It is easy for those skilled in the art to understand that, on the premise of no conflict, the above preferred solutions can be freely combined and superimposed.

[0132] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A tail seal grouting system for a shield tunneling in a full-face hard rock formation, characterized in that, Comprising: A wear-resistant grout stop brush structure, which is integrally annular and connected and fixed to the shield tail in a shape consistent with the shield tail. It includes an inner grout stop brush and an outer grout stop brush. The inner grout stop brush is connected and fixed to the first part of the shield tail through a first connection mechanism, and the outer grout stop brush is connected and fixed to the second part of the shield tail through a second connection mechanism. The first part is different from the second part, and both the inner grout stop brush and the outer grout stop brush open towards the rear of tunneling. The inner grout stop brush abuts against the segment, and the outer grout stop brush abuts against the surrounding rock; wherein, bolt holes are temporarily opened at the edge of the shield tail, and the wear-resistant grout stop brush structure is connected and fixed to the shield tail through a base plate; and, the outer grout stop brush includes a conventional grout stop brush and a grout-passing grout stop brush. The grout-passing grout stop brush is arranged at the position of the synchronous grouting pipe. The width of a single grout-passing grout stop brush is greater than that of the conventional grout stop brush, and at least one grouting pipe channel with the same aperture as the synchronous grouting pipe is opened at the position corresponding to the synchronous grouting pipe. The grouting pipe channel is used for passing through the extended synchronous grouting pipe; An airbag structure, which is integrally annular and arranged between the inner grout stop brush and the outer grout stop brush in a shape consistent with the shield tail. The airbag structure has a sealing surface facing the rear of tunneling, and in the inflated state, the inner area of the sealing surface is in close contact with the segment, and the outer area is in close contact with the surrounding rock.

2. The shield tail grout stop system according to claim 1, wherein: The base plate has a connecting section facing the front of tunneling. A first bolt hole is opened on the connecting section, and the connecting section is connected and fixed to the shield tail through a fixing bolt passing through the first bolt hole.

3. The shield tail grout stop system according to claim 2, wherein: The width of the base plate is 200 mm.

4. The shield tail grout stop system according to claim 2, wherein: A second bolt hole is further opened on the connecting section, and the first part is the position on the connecting section relatively close to the shield tail. The first connection mechanism is a tightening bolt, and the inner grout stop brush is connected and fixed to the connecting section through the tightening bolt passing through the second bolt hole.

5. The shield tail grout stop system according to claim 4, wherein: The base plate has an extending section facing the rear of tunneling. A third bolt hole is opened on the extending section. The second part is the position on the extending section relatively far from the shield tail. The second connection mechanism is a connecting bolt, and the outer grout stop brush is connected and fixed to the extending section through the connecting bolt passing through the third bolt hole.

6. The shield tail grout stop system according to claim 5, wherein: The extending section extends obliquely towards the outside of the shield tunnel.

7. The shield tail grout stop system according to claim 5, wherein: The second bolt hole is a single-row hole, and the third bolt hole is a double-row hole.

8. The shield tail grout stop system according to claim 5, wherein: There are multiple groups of the inner grout stop brushes, which are annularly arranged in a shape consistent with the shield tail and are composed of a wire brush, an inner protection plate, and an outer protection plate. Tightening bolt holes are correspondingly opened on the wire brush, the inner protection plate, and the outer protection plate.

9. The shield tail grout stop system according to claim 8, wherein: The wire plate brushes are arranged side by side, and the inner protection plate and the outer protection plate are overlapped and lapped on the inner and outer sides of the wire plate brushes.

10. The tail shield grout stop system according to claim 8, characterized in that: The single-piece width of the wire plate brush, the inner protection plate and the outer protection plate is 100 mm.

11. The tail shield grout stop system according to claim 5, characterized in that: There are multiple groups of the outer grout stop plate brushes, which are arranged in a ring shape consistent with the tail shield. One end is provided with double-row bolt holes and is connected to the extension section by double-row bolts. The other end is bent inward, and a fillet is made at the bending part.

12. The tail shield grout stop system according to claim 11, characterized in that: The bending treatment is a 90° bend.

13. The tail shield grout stop system according to claim 11, characterized in that: The outer grout stop plate brushes are connected and fixed to the extension section by an overlapping and lapping method, and a waterproof rubber is pasted between every two layers.

14. The tail shield grout stop system according to claim 11, characterized in that: The single-piece width of the outer grout stop plate brush is 100 mm.

15. The tail shield grout stop system according to claim 11, characterized in that: The outer grout stop plate brush is made of 65Mn spring steel.

16. The tail shield grout stop system according to claim 1, characterized in that: Two grouting pipe channels are provided.

17. The tail shield grout stop system according to claim 1, characterized in that: The overall width of a single-piece slurry-passing and grout-stopping plate brush is 365 mm, which is formed by overlapping and lapping two special 200-mm-wide grout-stopping plate brushes and two normal 100-mm-wide grout-stopping plate brushes. The connecting side edges of the two special 200-mm-wide grout-stopping plate brushes are reserved with the grouting pipe channels.

18. The tail shield grout stop system according to claim 1, characterized in that: The airbag structure is reserved with slurry-passing holes corresponding to the grouting pipe channels.

19. The tail shield grout stop system according to claim 1, characterized in that: The airbag structure also has an inflation surface facing the tunneling front, and at least two groups of air inlet holes and air outlet holes with an interval not greater than 180° are arranged on the inflation surface.

20. The tail shield grout stop system according to claim 1, characterized in that: The airbag structure is made of rubber and is made into a high-pressure thick rubber airbag by sandwiching two layers of nylon cloth between three layers of nitrile rubber, with a maximum bearing pressure of 5 bar.

21. The tail shield grout stop system according to claim 1, characterized in that: This tail shield grout stop system further includes: An airbag protection structure that at least surrounds the plugging surface of the airbag structure and can stretch with the inflation and expansion of the airbag.

22. The tail shield grout stop system according to claim 21, characterized in that: The airbag protection structure includes an outer package of wear-resistant elastic wire mesh, and the outer package of wear-resistant elastic wire mesh is coated on the plugging surface and bypasses the inner area and the outer area of the plugging surface and is connected and fixed to the base plate.

23. The tail shield grout stop system according to claim 22, characterized in that: The outer package of wear-resistant elastic wire mesh is connected and fixed to the base plate through a fixing steel plate.

24. The tail shield grout stop system according to claim 21, characterized in that: The airbag protection structure further includes an embedded wear-resistant elastic wire mesh, which is embedded in the surface layer or the interior of the airbag.

25. An installation method of the tail seal grouting system according to any one of claims 1 to 24, characterized in that, It includes: S1: Bore bolt holes. Bore bolt holes in the shield tail of the shield tunneling machine. S2: Install the base plate. First, install the base plate at the position of the synchronous grouting pipe, and then extend and connect it to both sides centered on this base plate until the entire ring of the shield tail is covered. S3: Install the inner slurry stop brush. Install the wire brush, the inner protection plate and the outer protection plate. The wire brushes are arranged side by side. The inner protection plate and the outer protection plate respectively adopt the method of three-layer overlapping and lapping, and finally fasten them with tightening bolts. S4: Install the outer slurry stop brush. First, install the slurry passing and stopping brush at the position of the synchronous grouting pipe, and then gradually lap and assemble the conventional slurry stop brushes centered on this slurry passing and stopping brush until the entire ring of the shield tail is covered. S5: Fill with sealing grease. After the installation of the entire wear-resistant slurry stop brush structure is completed, after the shield tunneling machine is hoisted into the well as a whole and assembled, fill the wire brush part with sealing grease. S6: Extend the synchronous grouting pipe. Carry out the extension operation of the synchronous grouting pipe in the well, and fixedly connect the extended synchronous grouting pipe to the shield tail by full welding. S7: Install the airbag. Position and install the whole-ring airbag between the inner slurry stop brush and the outer slurry stop brush, weld and connect it to the grouting pipe channel, and bolt-connect it to the fixed steel plate. S8: Install the outer-wrapped wear-resistant elastic wire mesh. Lay the outer-wrapped wear-resistant elastic wire mesh on the sealing surface of the airbag, and connect and fix both ends to the base plate. S9: Debug the air compressor and instruments. Check the airtightness of the airbag, check the connection condition, the opening degree and the elasticity of the sealing plate, and the installation is completed.

26. A construction method of the tail seal grouting system according to any one of claims 1 to 24, characterized in that, It includes: S1: The shield tunnels forward. After the tunneling is completed, segment assembly is carried out. S2: Set the air pressure and inflate the airbag. S3: Check the air pressure stability of the airbag. If it is unstable, check the airbag and reinflate it until the air pressure of the airbag is stable. S4: After the air pressure of the airbag is stable, carry out synchronous grouting / segment hole grouting. S5: After synchronous grouting / segment hole grouting, check whether the air pressure is stable until the filling / grouting of the entire ring of segments is completed. S6: Exhaust the airbag. The shield continues to tunnel forward, and prepare for the assembly and slurry stopping construction of the next ring of segments.

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