CN116752995B

CN116752995B - Construction method for collapse of shield tail top of open TBM full-face heading machine

Info

Publication number: CN116752995B
Application number: CN202310878491.9A
Authority: CN
Inventors: 李亚隆; 毛锦波; 张斌斌; 安佩娟; 赵红刚; 曾煜; 陈永刚; 于海涛
Original assignee: CCCC SHEC Dong Meng Engineering Co Ltd
Current assignee: CCCC SHEC Dong Meng Engineering Co Ltd
Priority date: 2023-07-18
Filing date: 2023-07-18
Publication date: 2025-12-19
Anticipated expiration: 2043-07-18
Also published as: CN116752995A

Abstract

This invention provides a construction method for addressing the collapse of the shield tail top of an open-face TBM (Tunnel Boring Machine). By analyzing the surrounding rock conditions at the face in front of the cutterhead through pre-drilling, the tunneling support parameters are adjusted. Corresponding support methods are adopted for the cavities formed by shield tail collapse during tunneling. Simultaneously, for strata with severe collapse and rockfall, long strip steel plates are densely arranged on the upper steel arch frame to utilize the reinforcement bar, enabling the open-face TBM to quickly and safely pass through complex strata such as folded zones without reinforcement bars. This allows the TBM to safely and quickly traverse long folded zones, thereby improving tunneling efficiency, reducing construction safety risks, and minimizing damage to machinery from rockfall and collapse. For cavities caused by collapse above the support shoe, a "strong support followed by filling" technique is adopted; for cavities at the support shoe, a "temporary filling followed by permanent filling" technique is adopted, ensuring safe and efficient tunneling of the open-face TBM.

Description

Construction method for collapse of shield tail top of open TBM full-face heading machine

Technical Field

The invention belongs to the technical field of TBM construction of long and large tunnels, and particularly relates to a construction method for collapse of the top of the shield tail of an open TBM full-face heading machine.

Background

The open TBM is widely applied in mountain long tunnel construction, the construction technology is mature day by day, especially, the advantages of quick tunneling can be fully exerted for hard strata with high stability of II level, III level, IV level and V level, but the TBM usually penetrates through a fold belt in the tunneling process, due to soft surrounding rock, broken rock and crack development, the top of a shield is usually accompanied with collapse blocks in the tunneling process, collapse cavities with different sizes are formed, construction safety is endangered, mechanical equipment is damaged, collapse occurs at the supporting shoes, the supporting shoes cannot be stressed uniformly, the supporting shoes cannot slip and cannot tunnel, temporary supporting is needed, smooth passing is achieved, meanwhile, a large amount of manpower is needed to be input for slag removal at the bottom of the collapsed shield, and the tunneling period is delayed.

Especially in the two lithology cross transition stages, the rock is in an embedded block structure, the integrity is poor, the stability is poor, the collapse is more serious, and the rapid tunneling of the TBM is influenced. Especially for the open type TBM without the reinforcement bar supporting function, the safety risk is greater during tunneling.

Disclosure of Invention

The invention provides a construction method for collapsing the top of the shield tail of an open TBM full-face tunneling machine, which solves the problems that the TBM has no reinforcement bar function but has the functions of die casting and opening and passes through a fold belt, adopts a corresponding supporting mode through a collapse cavity formed by collapsing the shield tail in the tunneling process, and simultaneously densely arranges strip-shaped steel plates on a steel arch frame of the last truss for a stratum with serious collapse and collapse block so as to play the role of reinforcement bar, thereby realizing the rapid and safe passage of the open TBM without reinforcement bar through complex strata such as the fold belt and the like, ensuring that the TBM safely and rapidly passes through the long-distance fold belt, further improving tunneling efficiency, reducing construction safety risks and damage of collapse block collapse to mechanical equipment.

The invention is realized by the following technical scheme:

a construction method for collapse of the top of the shield tail of an open TBM full-face heading machine comprises the following specific contents:

The collapse cavity depth caused by the collapse of the upper part of the supporting shoe is detected, and different strong supporting treatment measures are corresponding to different depths and positions, and the method is as follows:

i, when the collapse cavity depth H is less than 0.5m in the tunneling process in the range above the top of the shield tail support boot, the disposal measure of the collapse cavity is as follows:

Removing slag in a collapse cavity after finishing the N-th cyclic tunneling, performing primary injection concrete sealing on exposed surrounding rock of the collapse cavity by an L1-zone emergency spraying and mixing system, laying reinforcing steel meshes, installing an N-th cyclic steel arch, firmly welding the N-th cyclic steel arch and the N-1-th cyclic steel arch in a staggered manner by adopting a circumferential connecting rib, spraying concrete to a designed intrados by adopting a wet spraying and mixing zone, wherein the circumferential connecting rib spacing between the N-th cyclic steel arch and the N-1-th cyclic steel arch is B, the B is less than or equal to 100cm, and the spacing L between the N-th cyclic steel arch and the N-1-th cyclic steel arch is equal to the per-cyclic tunneling stroke L' of an open TBM;

II, when the shield tail support boot top is in the range of more than the top, collapsing to form a collapse cavity depth of 0.5m or less and H <2m, wherein the treatment measures are as follows:

S1, cleaning slag in the collapse cavity after the Nth circulation is separated from the shield tail, and performing primary injection concrete sealing on exposed surrounding rock of the collapse cavity of the Nth circulation by an L1 area emergency injection mixing system, laying N layers of dense reinforcing steel meshes, installing an Nth circulation type steel arch, wherein connecting ribs between the Nth circulation type steel arch and the N-1 th circulation type steel arch are replaced by strip-shaped steel members, and N is more than or equal to 2. The length of the strip steel member is equal to the spacing between the Nth circulating steel arch and the N-1 th circulating steel arch, and the strip steel member can be HW steel or channel steel. The annular distance between the section steel arches is B, and B is less than or equal to 80cm;

S2, a grouting guide pipe and a ventilation pipe are arranged in the Nth circulating collapse cavity and are welded with the Nth circulating steel arch frame, the distance between the grouting guide pipe and the ventilation pipe and the surrounding rock surface at the top of the collapse cavity is B, wherein B is less than or equal to 10cm, and the grouting guide pipe and the ventilation pipe have grouting and ventilation functions;

s3, blocking the grouting guide pipe and the tail part of the vent pipe, and supporting sprayed concrete for the Nth cyclic collapse cavity by an L1 area emergency spraying and mixing system, wherein the thickness of the sprayed concrete is more than or equal to 10cm;

s4, along with the forward tunneling of the open TBM, after the Nth cyclic collapse cavity is supported to a wet spraying machine in a spraying and mixing area, connecting a sprayed concrete pipeline, carrying out layered backfilling on concrete in the Nth cyclic collapse cavity to the top of the collapse cavity through a grouting conduit, and then spraying the concrete to an intrados surface by adopting the wet spraying machine in the spraying and mixing area, wherein the layered backfilling sequence of the concrete is from two sides to the middle and from bottom to high;

S5, detecting compactness by using monitoring equipment, judging whether grouting plugging is needed according to a monitoring result, and continuously monitoring and measuring;

And III, when the collapse cavity depth H is more than 2m in the tunneling process in the range above the top of the shield tail support boot and the shield tail surrounding rock continuously collapses and blocks in the tunneling process, the treatment measures are as follows:

s1, a bar-shaped steel plate is adopted to replace a steel bar net piece, after the installation of the Nth circulating type steel arch frame is completed, the bar-shaped steel plate is welded on the outer wing plate of the Nth circulating type steel arch frame in a circumferential close-packed mode, the dimension of the bar-shaped steel plate is L multiplied by B multiplied by h (longitudinal multiplied by circumferential multiplied by thickness), wherein L is equal to the tunneling stroke of the open type TBM, B is determined by the outer arc degree of the steel bar arch frame, h is less than or equal to 8mm, one end of the length direction of the bar-shaped steel plate is welded at the outer wing plate of the Nth circulating type steel arch frame, and one end of the bar-shaped steel plate extends into the inner side of the open type TBM shield and is tightly attached to the outer wing plate of the Nth+1 circulating type steel arch frame which is pre-installed on the inner side of the shield.

The circumferential radian range of the welding of the end part of the strip steel plate is determined according to the collapse degree of surrounding rock separated from the shield tail;

S2, when the open TBM is used for tunneling forward for the (N+1) -th cycle, the strip steel plate and the pre-installed (N+1) -th cycle steel arch are slowly separated from the inner side of the shield, stone falling from the tail of the shield is intercepted, after the (N+1) -th cycle tunneling is completed, the arch frame splicing machine is used for tightly supporting the (N+1) -th cycle steel arch to be tightly attached to surrounding rocks with the strip steel plate, the strip steel plate is firmly welded with the outer edge of the arch frame, and the (N+2) -th cycle steel plate, the (N+n) -th cycle steel plate and the steel arch frame are sequentially completed, and 1/2 of the outer wing plate of the (N+n) -th cycle steel arch frame is welded with the end part of the strip steel plate;

S3, after S2 is finished, a plurality of strip steel members are adopted between the n+n cycle steel arch and the N cycle steel arch to be firmly welded, wherein the strip steel members can be HW steel or channel steel, and the distance B is less than or equal to 60cm;

S4, punching holes at the positions of the (n+n) th circulation strip steel plate and the (N) th circulation strip steel plate, and installing grouting guide pipes and ventilation pipes, wherein the quincuncial arrangement of the grouting guide pipes and the ventilation pipes is welded with the profile steel arch, the distance between the grouting guide pipes and the ventilation pipes and the surrounding rock surface at the top of the collapse cavity is B, wherein B is less than or equal to 10cm, and the grouting guide pipes and the ventilation pipes have grouting and exhaust functions;

S5, along with tunneling of an open TBM, after an Nth cyclic collapse cavity support and an n+n cyclic collapse cavity support are connected to a wet spraying machine in a spraying and mixing area, carrying out concrete layered backfilling on the Nth cyclic collapse cavity and the n+n cyclic collapse cavity through a grouting conduit, and then spraying concrete to an intrados surface by adopting the wet spraying machine in the spraying and mixing area, wherein the concrete layered backfilling sequence is from two sides to the middle and from the bottom to the high, the concrete layered backfilling height is at least higher than the highest point N of a profile steel arch frame, wherein N is a natural number which is not zero, and the residual space of the collapse cavity is filled with light materials;

And S6, the N-th cycle and the N+n-th cycle collapse cavity support and spray concrete to the designed intrados.

IV, when the two side support boot parts collapse, the treatment measures are as follows:

when the cavity collapse depth H is less than 0.5m, dense reinforcing steel meshes are laid at intervals in the cavity collapse, the L1 area emergency spraying and mixing system sprays concrete to the designed intrados layer by layer, and the strength of the sprayed concrete is early strength concrete;

When the cavity collapse depth H is more than or equal to 0.5m, temporarily filling the cavity collapse position by adopting sand bags and sleepers, laying strip steel plates with L multiplied by B multiplied by H (longitudinal multiplied by circumferential multiplied by thickness) on the surface, and spraying concrete to the designed intrados layer by layer at the wet spraying machine from the cavity collapse to the spraying and mixing area after the supporting boots at the two sides pass safely.

Preferably, the construction steps of the reinforcing mesh sheet are as follows:

S1, steel components such as a reinforcing mesh sheet, connecting ribs and the like are processed and formed in a reinforcing yard in a centralized manner, and an MSV multifunctional rubber-tyred vehicle is transported to a material lifting platform by an open TBM (tunnel boring machine) rear supporting trolley;

S2, starting a material lifting platform, lifting steel members such as a reinforcing mesh sheet and connecting ribs to a rotary crane on the top of the L1 girder, lifting the rotary crane to the girder, and manually transporting to a designated area for installation;

s3, overlapping and welding one end of the Nth circulating reinforcing steel bar net sheet with one end of the N-1 th circulating reinforcing steel bar net sheet, wherein the overlapping length of the reinforcing steel bar net sheet is more than or equal to 30 times of the diameter of the reinforcing steel bar;

S4, assembling an nth circulating steel arch by an arch assembling machine, and rounding and tightly attaching a steel bar net sheet to a rock surface;

The supporting shoe and the reinforcing steel mesh below the bottom of the supporting shoe are installed before the wet spraying machine in the spraying and mixing area sprays concrete after the supporting shoe passes through the position.

Preferably, the section steel arch is installed as follows:

s1, intensively processing a section steel arch in a reinforced bar yard, transporting an MSV multifunctional rubber-tyred vehicle to an inverted arch crane through an open TBM (tunnel boring machine) rear supporting trolley, transporting to a service beam through the inverted arch crane, and transporting to an arch frame assembling machine through the service beam;

S2, the section steel arch frame is formed by splicing N section steel, connecting plates are arranged at the ends of the N section steel and the N+1 section steel, the N section steel and the N+1 section steel are connected into a whole through M bolts, an arch frame splicing machine grabbing head grabs the N section steel and rotates to vacate the installation position of the N+1 section steel, then the N+1 section steel is installed and rotated, the N+n section steel is installed in sequence, wherein M is more than or equal to 4, and N is a natural number which is not zero;

S3, the assembled section steel arch is moved to a designated position by the tightening device, the circle is tightened to be tightly attached to the rock face, the reinforcing ribs are installed, the nuts of the connecting plates are tightened, and joints of the section steel arch in the Nth cycle and the (n+1) th cycle are staggered by at least 50%;

S4, installing the annular connecting ribs among the Nth cycle, the N+1 th cycle and the N+n th cycle, and installing the supporting shoe and the connecting rib at the bottom of the supporting shoe before the wet spraying machine in the spraying and mixing area sprays concrete after the supporting shoe passes.

Preferably, the grouting plugging step comprises the following steps:

S1, forward prefabricating an overhead arch block in a centralized manner in a prefabricating field, conveying the overhead arch block to an inverted arch crane by adopting an MSV multifunctional rubber tire vehicle through an open TBM and a matched trolley, and installing a water stop strip on the Nth inverted arch block before conveying;

S2, cleaning an N-th inverted arch block installation area, installing cushion blocks, and installing the inverted arch crane to a designated position in a rotary manner after lifting;

S3, installing bolts between the N block and the N-1 inverted arch block and screwing the bolts;

s4, connecting a grouting pipeline to perform grouting plugging;

the installation of the upward arch blocks and the construction of the steel mesh and the section steel arch are not mutually interfered, can be independently performed.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. Three strong supporting modes and supporting modes when the two side supporting shoe parts collapse cavities are provided for the open TBM to penetrate through the fold zone collapse stratum, the three strong supporting modes and the supporting modes are flexibly adopted according to the condition of the shield tail collapse and collapse block and the size of the collapse cavity, and the risk of initial supporting deformation and even collapse of the collapse block-collapse stratum due to insufficient initial supporting strength is reduced.

2. Aiming at the open TBM without the reinforcement bar function or with insufficient reinforcement bar strength to resist the pressure of collapse slag, the method has the advantages that the strip steel plates are densely arranged and welded at the outer wing plates of the upper steel arch frame, the strip steel plates move backwards to block the collapse slag at the top of the shield along with the tunneling of the open TBM, the construction is safe and reliable, the safety risk is low, the damage of the collapse slag to personnel and equipment in the tunneling process is avoided, and the tunneling efficiency of the open TBM in a corrugated belt is improved.

3. For the small space in the matched trolley behind the open TBM, the general vehicle cannot be freely taken out, and the material transportation of the open TBM such as a profile steel arch, a steel bar net sheet, an overhead arch block and the like in the tunneling process is completed by adopting an MSV multifunctional rubber-tyred vehicle. The MSV multifunctional rubber-tyred vehicle has the double-head driving function, can be freely moved, is convenient and quick, is not limited by clearance of a rear matched trolley, and provides reliable material transportation guarantee for tunneling of an open TBM.

Drawings

The accompanying drawings, which are included to provide a further understanding of embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a schematic illustration of an open TBM in accordance with an embodiment of the present invention;

FIG. 3 is an enlarged view of A in a schematic view of an open TBM in accordance with an embodiment of the present invention;

FIG. 4 is an enlarged view of B in a schematic view of an open TBM in accordance with an embodiment of the present invention;

FIG. 5 is an enlarged view of C in a schematic view of an open TBM in accordance with an embodiment of the present invention;

FIG. 6 is a schematic illustration of an open TBM jumbolter in accordance with an embodiment of the present invention;

FIG. 7 is a schematic view of left and right side strut shoes of an open TBM in accordance with an embodiment of the present invention;

FIG. 8 is a schematic diagram of an MSV multi-functional cart in accordance with an embodiment of the present invention;

FIG. 9 is a cross-sectional view I of a continuous belt conveyor arrangement in accordance with an embodiment of the present invention;

FIG. 10 is a cross-sectional view II of a continuous belt conveyor arrangement in accordance with an embodiment of the present invention;

FIG. 11 is a schematic view of a support with a collapsed cavity of 0.5-2 m in an embodiment of the invention;

FIG. 12 is a schematic view of a collapsed cavity with a depth of 2m and above in an embodiment of the invention.

In the figure, a 1-cutter head, a 2-shield, a 3-arch frame assembling machine, a 4-anchor rod drilling machine, a 5-emergency spraying and mixing system, a 6-supporting shoe, a 7-rear support, an 8-upward arch block, a 9-inverted arch crane, a 10-rotary crane, a 11-material lifting platform, a 12-spraying and mixing area wet spraying machine, a No. 13-No. 1 trolley main control room, a 14-concrete conveying pump, a 15-concrete tank, a 16-concrete tank crane, a 17-MSV multifunctional rubber-tire vehicle, an 18-continuous belt conveyor, a 19-concrete layered backfilling machine, a 20-grouting guide pipe, a 21-ventilation pipe, a 22-sprayed concrete, a 23-shaped steel arch frame, a 24-reinforcing steel mesh, 25-bar steel members, 25-connecting ribs, 26-bar steel plates, 27-lightweight materials and 28-service beams are shown.

Detailed Description

For the purpose of making apparent the objects, technical solutions and advantages of the present invention, the present invention will be further described in detail with reference to the following examples and the accompanying drawings, wherein the exemplary embodiments of the present invention and the descriptions thereof are for illustrating the present invention only and are not to be construed as limiting the present invention. It should be noted that the present invention is already in a practical development and use stage.

1-12, A construction method for collapsing the top of the shield tail of an open TBM full-face heading machine comprises the following steps:

Preferably, the section steel arch is installed as follows:

S3, installing the annular connecting ribs among the Nth cycle, the N+1 th cycle and the N+n th cycle, and installing the supporting shoe and the connecting rib at the bottom of the supporting shoe before the wet spraying machine in the spraying and mixing area sprays concrete after the supporting shoe passes.

Preferably, the grouting plugging step comprises the following steps:

s4, connecting a grouting pipeline to perform grouting plugging;

Examples

As shown in fig. 2 to 12, a 22.13 km-level extra-long tunnel is arranged in Xinjiang, a 3 hole and 4 shaft design scheme is adopted in the high-cold high-altitude area, an open TBM (tunnel boring machine) method is adopted in the middle pilot tunnel, the excavation diameter is 8430mm, the total machine length is 285m, and the device has the functions of pressure injection and open excavation, so that the design of a steel bar row is canceled by lengthening the shield 2 to 10 m.

And tunneling 10.801km of tunnel outlet end open TBM, and sequentially passing through the medium-stroke granite porphyry, marble sandy slate and granite. The belt 3576m is influenced by the medium mountain folds, mainly a marble sand inclusion paper board, the harder rock is in a block mosaic structure, collapse is encountered 54 times in the process, and the collapse occurs on the top of the two-side supporting boots 6, wherein the maximum collapse cavity is 13m multiplied by 7.3m multiplied by 6m (longitudinal multiplied by circumferential multiplied by depth), meanwhile, light micro-blocking is accompanied, and the collapse cavity is treated for 7 days.

The open TBM in the embodiment comprises a cutter head 1, a shield 2, an arch centering assembly machine 3, an anchor rod drilling machine 4, an emergency spraying and mixing system 5, a supporting shoe 6, a rear support 7, an arch centering block 8, an inverted arch crane 9, a rotary crane 10, a material lifting platform 11, a spraying and mixing area wet spraying machine 12, a No. 1 trolley main control room 13, a concrete conveying pump 14, a concrete tank 15, a concrete tank crane 16, an MSV multifunctional rubber-tyred vehicle 17, a continuous belt conveyor 18, a concrete layering backfill 19, a grouting guide pipe 20, a ventilation pipe 21, a sprayed concrete 22, a section steel arch 23, a steel mesh 24, a strip steel member 25, a connecting rib 25, a strip steel plate 26, a lightweight material 27 and a service beam 28.

The present example is one of the 54 collapses with the largest collapse occurring at the top of the two side support shoes 6, the collapse cavity being 13m x 7.3m x 6m (longitudinal x circumferential x depth) with light micro-jamming.

At this time, the depth of the collapse cavity exceeds 2m, so that a III-type strong supporting mode is used, and the steps are as follows:

s1, a bar-shaped steel plate 26 is adopted to replace a reinforcing mesh 24, after the installation of the Nth circulating type steel arch 23 is completed, the bar-shaped steel plate 26 is welded on the outer wing plate of the Nth circulating type steel arch 23 in a circumferential close-packed manner, the size of the bar-shaped steel plate 26 is L multiplied by B multiplied by h (longitudinal multiplied by circumferential multiplied by thickness), wherein L is equal to the tunneling stroke of the open type TBM, B is determined by the outer arc degree of the steel arch 23, h is less than or equal to 8mm, one end of the length direction of the bar-shaped steel plate 26 is welded at the outer wing plate of the Nth circulating type steel arch 23, and one end of the bar-shaped steel plate 26 extends into the inner side of the open type TBM shield 2 and is tightly attached to the outer wing plate of the (n+1) circulating type steel arch 23 which is pre-installed on the inner side of the shield 2.

The circumferential radian range of the welding of the end part of the strip steel plate 26 is determined according to the collapse degree of surrounding rock separated from the shield tail;

S2, when the open TBM is used for tunneling forward for the (N+1) -th cycle, the strip steel plate 26 and the pre-installed (N+1) -th cycle steel arch 23 slowly fall out of the inner side of the shield 2, stone falling from the shield tail is intercepted, after the (N+1) -th cycle tunneling is completed, the arch centering assembly machine 3 tightly supports the (N+1) -th cycle steel arch 23 and the strip steel plate 26 to be tightly attached to surrounding rocks, the strip steel plate 26 is firmly welded with the outer edge of the arch, and the (N+2) -th cycle steel plate 26 and the steel arch 23 sequentially complete, wherein 1/2 of the outer wing plate of the (N+n) -th cycle steel arch 23 is welded with the end part of the strip steel plate 26;

s3, after S2 is finished, a plurality of strip steel members 25 are adopted to be firmly welded between the n+n circulating type steel arch 23 and the N circulating type steel arch 23, wherein the strip steel members 25 can be HW type steel or channel steel, and the interval B is less than or equal to 60cm;

S4, punching holes at the positions of the (n+n) th circulation and (N) th circulation strip steel plates 26, and installing grouting guide pipes 20 and ventilation pipes 21, wherein the quincuncial arrangement of the grouting guide pipes 20 and the ventilation pipes 21 is welded with a profile steel arch 23, the distance between the grouting guide pipes 20 and the ventilation pipes 21 and the surrounding rock surface at the top of the collapse cavity is B, wherein B is less than or equal to 10cm, and the grouting guide pipes 20 and the ventilation pipes 21 have grouting and exhaust functions;

S5, along with tunneling of an open TBM, after an Nth cyclic collapse cavity support and an N+n cyclic collapse cavity support are connected to a wet spraying machine 12 in a spraying and mixing area, a sprayed concrete 22 pipeline is connected to perform concrete layered backfilling 19 on the Nth cyclic collapse cavity and the N+n cyclic collapse cavity through a grouting conduit 20, then the wet spraying machine 12 in the spraying and mixing area is adopted to spray concrete 22 to an intrados surface, the concrete layered backfilling 19 is sequentially from two sides to the middle and from the bottom to the top, the height of the concrete layered backfilling 19 is at least higher than the highest point N of a profile steel arch 23, wherein N is a natural number which is not zero, and the residual space of the collapse cavity is filled with a light material 27;

And S6, the Nth cycle and the N+n cycle collapse cavity are used for supporting and spraying concrete 22 to the designed intrados, and the continuous belt conveyor 18 is hung right above the tunnel roof through a mortar anchor rod matched with a guide chain.

The construction steps of the reinforcing mesh 24 are as follows:

S1, steel components such as a reinforcing mesh 24 and connecting ribs 25 are processed and formed in a reinforcing yard in a centralized mode, and the MSV multifunctional rubber-tyred vehicle 17 is transported to the material lifting platform 11 through an open TBM and a matched trolley.

S2, starting the material lifting platform 11, lifting steel members such as the reinforcing mesh 24 and the connecting ribs 25 to the rotary crane 10 on the top of the L1 girder, lifting the rotary crane 10 to the girder, and manually transporting to a designated area for installation.

S3, overlapping and welding one end of the Nth circulating reinforcing steel bar mesh 24 with one end of the N-1 th circulating reinforcing steel bar mesh 24. The overlap length of the reinforcing mesh 24 is more than or equal to 30 times of the diameter of the reinforcing.

S4, assembling the nth circulating steel arch 23 by the arch assembling machine 3, and rounding the steel mesh 24 to be tightly attached to the rock surface.

The shoe 6 and the reinforcing mesh 24 below the bottom of the shoe 6 are installed before the wet spraying machine 12 in the spraying and mixing area sprays the concrete 22 after the shoe 6 passes through the position.

The installation steps of the section steel arch 23 are as follows:

s1, intensively processing the section steel arch 23 in a reinforced bar yard, transporting the MSV multifunctional rubber-tyred vehicle 17 to an inverted arch crane 9 through an open TBM and a matched trolley, transporting to a service beam 28 through the inverted arch crane 9, and transporting to an arch assembly machine 3 through the service beam 28.

S2, the section steel arch 23 is formed by splicing N section steel, connecting plates are arranged at the ends of the N section and the N+1 section, the N section steel and the N section steel are connected into a whole through M bolts, the arch centering splicing machine 3 grabs the N section steel and rotates to vacate the installation position of the N+1 section steel, then the N+1 section steel is installed and rotated, and the N+n section steel is installed in sequence. Wherein M is more than or equal to 4, and N is a natural number which is not zero.

S3, the assembled section steel arch 23 is moved to a designated position by the tightening device, the circle is tightened to be tightly attached to the rock face, the reinforcing ribs are arranged, and the connecting plate nuts are tightened. The joints of the Nth circulation and the (n+1) th circulation type steel arches 23 are staggered by at least 50 percent.

S4, installing the annular connecting ribs 25 among the Nth cycle, the N+1th cycle and the N+n th cycle. The supporting shoe 6 and the connecting ribs 25 at the bottom of the supporting shoe 6 are arranged before the wet spraying machine 12 in the spraying and mixing area sprays the concrete 22 after the supporting shoe 6 passes

The grouting plugging steps are as follows:

s1, performing centralized forward prefabrication on the inverted arch blocks 8 in a prefabrication field, and conveying the inverted arch blocks to an inverted arch crane 9 by adopting an MSV multifunctional rubber-tyred vehicle 17 through an open TBM rear supporting trolley. The Nth inverted arch block 8 is provided with a water stop strip before transportation.

S2, cleaning an installation area of the N inverted arch block 8, and installing cushion blocks. The inverted arch crane 9 is lifted and mounted to a designated position by rotation.

S3, installing bolts between the N th block and the N-1 th inverted arch block 8 and screwing.

S4, connecting a grouting pipeline to perform grouting plugging.

The installation of the inverted arch block 8 and the construction of the reinforcing mesh 24, the section steel arch 23, the system anchor rod and the sprayed concrete 22 are not interfered with each other, and can be independently carried out.

Finally, under the method of the invention, the time for treating the collapse cavity is 7 days, thereby reducing the falling of the collapse stone and the damage to mechanical equipment, improving the tunneling efficiency and improving the safety degree. The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims

1. A construction method for addressing the collapse of the top of the shield tail of an open-face TBM (tunnel boring machine), characterized by the following measures:

The depth of the collapse cavity caused by the collapse of the upper part of the probe support (6) was determined. Different strong support measures were taken according to different depths and locations, as follows:

Ⅰ: When a collapse occurs during excavation above the top of the shield tail support shoe (6), forming a cavity with a depth H < 0.5m, the measures to handle the cavity are as follows:

After the Nth cycle of tunneling is completed, the shield tail is removed and the slag inside the collapse cavity is cleaned. The L1 area emergency shotcrete system (5) seals the exposed surrounding rock of the Nth cycle collapse cavity with initial shotcrete (22), lays steel mesh (24), and installs the Nth cycle steel arch frame (23). The Nth cycle steel arch frame (23) and the N-1 cycle steel arch frame (23) are firmly welded together with circumferential connecting bars (25). The shotcrete area wet shotcrete machine (12) sprays concrete (22) to the designed inner arc surface. The spacing of the circumferential connecting bars (25) between the Nth cycle steel arch frame (23) and the N-1 cycle steel arch frame (23) is B, and B≤100cm. The spacing L between the Nth cycle steel arch frame (23) and the N-1 cycle steel arch frame (23) is equal to the tunneling distance L′ of each cycle of the open TBM.

II: When the area above the top of the shield tail support shoe (6) collapses during excavation, forming a cavity with a depth of 0.5m ≤ H < 2m, the treatment measures are as follows:

S1: After the Nth cycle exits the shield tail, the slag inside the collapse cavity is cleaned. The L1 area emergency spraying system (5) seals the exposed surrounding rock of the Nth cycle collapse cavity with initial sprayed concrete (22), lays n layers of dense steel mesh (24), and installs the Nth cycle steel arch frame (23). The connecting bar (25) between the Nth cycle steel arch frame (23) and the N-1th cycle steel arch frame (23) is replaced by a strip steel component (25), where n≥2. The length of the strip steel component (25) is equal to the distance between the Nth cycle steel arch frame (23) and the N-1th cycle steel arch frame (23). The strip steel component (25) is HW steel or channel steel. The circumferential spacing of the steel arch frame (23) is B, and B≤80cm.

S2: Grouting pipe (20) and ventilator (21) are installed in the Nth cycle collapse cavity. The grouting pipe (20) and ventilator (21) are arranged in a quincunx pattern and welded to the Nth cycle steel arch frame (23). The distance between the grouting pipe (20) and ventilator (21) and the top surrounding rock surface of the collapse cavity is B, where B≤10cm. The grouting pipe (20) and ventilator (21) have both grouting and ventilation functions.

S3: Block the tail of the grouting pipe (20) and the vent pipe (21), and spray concrete (22) for the Nth cycle collapse cavity support of the L1 area emergency spraying system (5), wherein the thickness of the sprayed concrete (22) is ≥10cm;

S4: As the open-face TBM advances forward, after the Nth cycle collapse cavity is supported to the wet shotcrete machine (12) in the shotcrete zone, the shotcrete (22) pipeline is connected to the grouting pipe (20) to backfill the Nth cycle collapse cavity with concrete in layers (19) to the top of the collapse cavity. Then, the wet shotcrete machine (12) in the shotcrete zone is used to spray concrete (22) to the inner arc surface. The sequence of the concrete backfilling (19) is from both sides to the middle and from the bottom to the top.

S5: Use monitoring equipment to test its density, determine whether grouting is needed for sealing based on the monitoring results, and continuously monitor and measure.

III: When the area above the top of the shield tail support shoe (6) collapses during excavation, forming a cavity depth H > 2m, and the surrounding rock of the shield tail continues to collapse and fall off during excavation, the following measures shall be taken:

S1: Strip steel plate (26) is used instead of steel mesh (24). After the Nth cycle steel arch frame (23) is installed, strip steel plate (26) is welded in close rows around the outer wing plate of the Nth cycle steel arch frame (23). The dimensions of the strip steel plate (26) are L×B×h, longitudinal×circular×thickness, where L is equal to the excavation stroke of the open TBM, B is determined by the outer arc of the steel arch frame (23), and h≤8mm. One end of the strip steel plate (26) is welded to the outer wing plate of the Nth cycle steel arch frame (23) in the length direction, and the other end extends into the inner side of the open TBM shield (2) and is in close contact with the outer wing plate of the N+1 cycle steel arch frame that is pre-installed inside the shield.

The circumferential arc range welded to the end of the strip steel plate (26) is determined according to the degree of collapse of the shield tail detached from the surrounding rock;

S2: When the open-type TBM advances forward for the N+1th cycle, the strip steel plate (26) and the pre-installed N+1th cycle steel arch frame slowly detach from the inside of the shield (2) to intercept the rocks falling from the shield tail. After the N+1th cycle of tunneling is completed, the arch frame assembly machine tightens the N+1th cycle steel arch frame so that it is close to the surrounding rock with the strip steel plate, and welds the strip steel plate to the outer flange of the arch frame firmly. The strip steel plate (26) and steel arch frame (23) of the N+2th and N+nth cycles are completed in sequence. Half of the outer flange of the N+nth cycle steel arch frame (23) is welded to the end of the strip steel plate (26).

S3: After S2 is completed, multiple strip steel components (25) are welded firmly between the N+n cycle steel arch frame (23) and the Nth cycle steel arch frame (23). The strip steel components (25) are HW steel or channel steel, and the spacing B is ≤60cm.

S4: Drill holes in the N+n and Nth cycles of the strip steel plate (26) and install grouting pipe (20) and vent pipe (21). The grouting pipe (20) and vent pipe (21) are arranged in a quincunx pattern and welded to the steel arch frame (23). The distance between the grouting pipe (20) and vent pipe (21) and the surrounding rock surface at the top of the collapsed cavity is B, where B≤10cm. The grouting pipe (20) and vent pipe (21) have both grouting and venting functions.

S5: As the open-type TBM is excavated, after the Nth cycle collapse cavity support and the N+nth cycle collapse cavity support are connected to the wet shotcrete machine (12) in the shotcrete zone, the shotcrete (22) pipeline is connected to the grouting pipe (20) to backfill the Nth cycle and N+nth cycle collapse cavity with concrete in layers (19). Then, the wet shotcrete machine (12) in the shotcrete zone is used to spray concrete (22) onto the inner arc surface. The concrete backfilling (19) sequence is from both sides to the middle and from bottom to top. The height of the concrete backfilling (19) is at least higher than the highest point N of the steel arch frame (23), where N is a non-zero natural number. The remaining space of the collapse cavity is filled with lightweight material (27) and compacted.

S6: Shotcrete (22) for cavity support in the Nth and N+nth cycles to the designed inner arc surface;

IV: When the cavity collapses at the two sides of the support boot (6), the following measures shall be taken:

When the depth of the collapsed cavity H < 0.5m, a dense steel mesh (24) is laid at a certain interval in the collapsed cavity, and the L1 area emergency spraying system (5) sprays concrete (22) in layers to the designed inner arc surface. The strength of the sprayed concrete (22) is early strength concrete.

When the depth of the collapsed cavity H≥0.5m, the collapsed cavity is temporarily filled with sandbags and sleepers, and the surface is covered with a strip steel plate (26) with L×B×h, longitudinal × circumferential × thickness. After the support boots (6) on both sides have passed safely, the collapsed cavity is sprayed with concrete (22) in layers to the wet spraying machine (12) in the spraying area to the designed inner arc surface.

2. The construction method for the collapse of the top of the shield tail of an open-face TBM tunneling machine according to claim 1, characterized in that the construction steps of the steel mesh (24) are as follows:

S1. Steel components such as steel mesh (24) and connecting bars (25) are processed and formed in the steel yard. The MSV multi-functional rubber-wheeled vehicle (17) is transported to the material lifting platform (11) via the open TBM and the matching trolley.

S2. Start the material lifting platform (11) to lift the steel components such as steel mesh (24) and connecting bars (25) to the rotating crane (10) on the top of the L1 main beam. The rotating crane (10) lifts the main beam and is then manually transported to the designated area for installation.

S3. One end of the Nth cycle steel mesh (24) is overlapped and welded to one end of the N-1th cycle steel mesh (24), wherein the overlap length of the steel mesh (24) is ≥30 times the diameter of the steel bar;

S4. Arch frame assembly machine (3) assembles the Nth cycle type steel arch frame (23), and supports it in a round shape to fit tightly against the steel mesh (24) so that it fits tightly against the rock surface;

The aforementioned support boot (6) and the steel mesh (24) below the bottom of the support boot (6) are installed after the support boot (6) passes through this part and before the wet spraying machine (12) sprays concrete (22).

3. The construction method for the collapse of the top of the shield tail of an open-face TBM tunneling machine according to claim 1, characterized in that the installation steps of the steel arch frame (23) are as follows:

S1. The steel arch frame (23) is centrally processed in the steel bar yard. The MSV multi-functional rubber-wheeled vehicle (17) is transported to the arch crane (9) via the open TBM and the matching trolley. It is then transported to the service beam (28) via the arch crane (9) and then to the arch frame assembly machine (3) via the service beam (28).

S2. The steel arch frame (23) is assembled from N sections of steel. The Nth section and the N+1th section are connected by M bolts. The arch frame assembly machine (3) grabs the Nth section and rotates it to make room for the N+1th section. Then it installs the N+1th section and rotates it. The N+nth section is installed in sequence. M≥4 and N is a non-zero natural number.

S3. The bracing device moves the assembled steel arch frame (23) to the designated position, braces it tightly against the rock surface and installs reinforcing ribs, and tightens the connecting plate nuts. The joints of the steel arch frame (23) in the Nth and N+1th cycles are staggered by at least 50%.

S4. Install the circumferential connecting bars (25) between the Nth cycle, the N+1th cycle, and the N+nth cycle. The bottom connecting bars (25) of the support shoe (6) and the support shoe (6) are installed after the support shoe (6) has passed and before the wet spraying machine (12) sprays concrete (22) in the spraying area.

4. The construction method for the collapse of the top of the shield tail of an open-face TBM tunneling machine according to claim 1, characterized in that the above-mentioned grouting and sealing step is as follows:

S1. The inverted arch block (8) is prefabricated in a centralized forward manner at the prefabrication yard. It is transported to the inverted arch crane (9) by an MSV multi-functional rubber-wheeled vehicle (17) via an open TBM and a matching trolley. The Nth inverted arch block (8) is prefabricated with a waterstop strip before transportation.

S2. Clean the installation area of the Nth inverted arch block (8), install the pad block, and use the inverted arch crane (9) to lift and rotate the installation to the designated position;

S3. Install and tighten the bolts between the Nth and N-1th inverted arch blocks (8);

S4. Connect the grouting pipeline for grouting and sealing;

The installation of the inverted arch block (8) does not interfere with the construction of the steel mesh (24) and the steel arch frame (23) and can be carried out independently.