Construction method for open type TBM full face tunnel boring machine shield tail top collapse

Abstract

The application provides a construction method for open TBM full-face tunneling machine shield tail top collapse, which adjusts the tunneling support parameters by analyzing the surrounding rock conditions of the tunnel face in front of the cutter head through advanced drilling. The corresponding support mode is adopted for the collapse cavity formed by the shield tail collapse in the tunneling process. Meanwhile, long strip steel plates are densely arranged on the last set of steel arches for the serious collapse block stratum, which plays the role of steel bar row, realizes the open TBM fast and safe passing through the complex stratum such as fold belt without steel bar row, so that the TBM safely and quickly passes through the long distance fold belt, and further improves the tunneling efficiency, reduces the construction safety risk and the damage of the mechanical equipment caused by the collapse block collapse, and adopts the technical measures of "strong support and then filling" for the collapse cavity caused by the upper collapse of the support shoe, and adopts the technical measures of "temporary filling first and then permanent filling" for the collapse cavity at the support shoe, so as to ensure the safe and efficient tunneling of the open TBM.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of long tunnel TBM construction, and particularly relates to a construction method for collapse of a shield tail top of an open TBM full-face tunneling machine. BACKGROUND

[0002] The open TBM has been widely applied in the construction of long tunnels in mountain ranges, and its construction technology is increasingly mature. In particular, it can fully exert the advantage of rapid excavation in good hard strata of grade II, grade III, grade IV and grade V stability. However, in the process of excavation, the TBM usually passes through a fold belt. Due to the softness of the surrounding rock, the broken rock and the development of cracks, the top of the shield is usually accompanied by collapse and block formation, forming a collapsed cavity of different sizes, which endangers the safety of construction and damages the mechanical equipment. Collapse occurs at the support shoe, causing uneven stress on the support shoe and causing the support shoe to slip and fail to excavate. Temporary support is required to successfully pass through. At the same time, the collapsed slag falls to the bottom of the shield, requiring a large amount of manpower to clean the slag, delaying the excavation period.

[0003] Especially in the transition stage of two kinds of lithology, the rock is in mosaic block structure, the integrity is poor, the stability is poor, and the collapse is more serious, which affects the rapid excavation of the TBM. In particular, the open TBM without steel bar support function has greater safety risks during excavation. SUMMARY

[0004] The present application provides a construction method for collapse of a shield tail top of an open TBM full-face tunneling machine, which solves the construction method for TBM without steel bar support function but with die casting and open function passing through a fold belt. The collapsed cavity formed by the collapse of the shield tail during excavation is supported in a corresponding way, and long strip steel plates are densely arranged on the last arch of the steel arch for serious collapse and block formation, which plays the role of steel bar support, enabling the open TBM without steel bar support to pass through complex strata such as fold belts safely and quickly, thereby enabling the TBM to pass through long distance fold belts safely and quickly, and further improving the excavation efficiency and reducing the damage of the collapse of the block to the mechanical equipment.

[0005] The present application is implemented by the following technical solutions:

[0006] A construction method for collapse of a shield tail top of an open TBM full-face tunneling machine, the specific contents are as follows:

[0007] Detect the depth of the collapsed cavity caused by the collapse of the upper part of the support shoe. Different support measures are taken according to different depths and positions, as follows:

[0008] I: When the depth H of the collapsed cavity formed by the collapse above the top of the shield tail support shoe during excavation is less than 0.5m, the disposal measure for the collapsed cavity is:

[0009] After the Nth cycle of tunneling is completed, the tail shield is pulled out, the inside of the collapsed cavity is cleaned, the exposed surrounding rock of the Nth cycle of collapsed cavity is closed by the initial spraying of the L1 area emergency shotcrete system, the steel mesh is laid, the Nth cycle of steel arch is installed, the Nth cycle of steel arch and the Nth-1 cycle of steel arch are firmly connected by the ring-shaped connecting rib staggered welding, the shotcrete is sprayed to the designed inner arc surface by the wet shotcrete machine in the shotcrete area, the distance between the ring-shaped connecting rib between the Nth cycle of steel arch and the Nth-1 cycle of steel arch is B, and B≤100cm, the distance L between the Nth cycle of steel arch and the Nth-1 cycle of steel arch is equal to the tunneling distance L' of the open TBM per cycle;

[0010] II: When the tunneling process in the range above the top of the tail shield support shoe collapses to form a collapsed cavity with a depth of 0.5m≤H<2m, the treatment measures are:

[0011] S1: After the Nth cycle of tail shield is pulled out, the inside of the collapsed cavity is cleaned, the exposed surrounding rock of the Nth cycle of collapsed cavity is closed by the initial spraying of the L1 area emergency shotcrete system, n layers of dense steel mesh are laid, the Nth cycle of steel arch is installed, and the connecting rib between the Nth cycle of steel arch and the Nth-1 cycle of steel arch is replaced by a strip-shaped steel member, wherein n≥2. The length of the strip-shaped steel member is equal to the distance between the Nth cycle of steel arch and the Nth-1 cycle of steel arch, and the strip-shaped steel member can be an HW steel or a channel steel. The ring-shaped distance of the steel arch is B, and B≤80cm;

[0012] S2: The grouting pipe and the air pipe are installed in the Nth cycle of collapsed cavity, the grouting pipe and the air pipe are arranged in a quincunx shape and welded with the Nth cycle of steel arch, the distance between the grouting pipe and the air pipe and the top surrounding rock surface of the collapsed cavity is B, wherein B≤10cm, and the grouting pipe and the air pipe have the functions of grouting and air permeation;

[0013] S3: The tail part of the grouting pipe and the air pipe is blocked, the Nth cycle of collapsed cavity support is sprayed with shotcrete by the L1 area emergency shotcrete system, and the thickness of the sprayed shotcrete is≥10cm;

[0014] S4: As the open TBM advances, after the Nth cycle of collapsed cavity support is behind the wet shotcrete machine in the shotcrete area, the connecting shotcrete pipeline passes through the grouting pipe to perform layered backfilling of the Nth cycle of collapsed cavity with shotcrete to the top of the collapsed cavity, and then the wet shotcrete machine in the shotcrete area is used to spray shotcrete to the inner arc surface, and the layered backfilling sequence is from both sides to the middle and from the bottom to the top;

[0015] S5: The monitoring equipment is used to detect the compactness, and whether grouting is needed is determined according to the monitoring results, and the monitoring and measurement are continuously performed;

[0016] III: When the tunneling process in the range above the top of the tail shield support shoe collapses to form a collapsed cavity with a depth of H>2m, and the surrounding rock of the tail shield continuously collapses and drops during the tunneling process, the treatment measures are:

[0017] S1: replace the steel mesh with a strip steel plate, after the installation of the Nth cycle steel arch frame, the strip steel plate is densely welded around the outer wing plate of the Nth cycle steel arch frame, the size of the strip steel plate is LxBxh (length x ring direction x thickness), wherein L is equal to the open TBM tunneling distance, B is determined by the outer arc of the steel arch frame, h≤8mm, one end of the strip steel plate in the length direction is welded at the outer wing plate of the Nth cycle steel arch frame, one end extends into the inside of the open TBM shield, and is in close contact with the pre-installed outer wing plate of the N+1th cycle steel arch frame inside the shield.

[0018] The range of the ring direction arc of the end of the strip steel plate is determined according to the collapse degree of the surrounding rock after the shield tail is out of the surrounding rock;

[0019] S2: when the open TBM tunnels forward to the N+1th cycle, the strip steel plate and the pre-installed N+1th cycle steel arch frame slowly come out of the inside of the shield, intercept the falling stones of the shield tail, after the N+1th cycle tunneling is completed, the arch assembling machine tightens the N+1th cycle steel arch frame to make it in close contact with the surrounding rock, and the strip steel plate is welded firmly with the outer wing of the arch, and the strip steel plate and the steel arch frame of the N+2th cycle, the N+nth cycle are sequentially completed, 1 / 2 of the outer wing plate of the N+nth cycle steel arch frame is welded with the end of the strip steel plate;

[0020] S3: after S2 is completed, a plurality of strip steel members are welded firmly between the N+nth cycle steel arch frame and the Nth cycle steel arch frame, the strip steel member can be HW steel or channel steel, and the interval B≤60cm;

[0021] S4: the N+nth cycle and the Nth cycle strip steel plate part is punched, and a grouting guide pipe and a ventilation pipe are installed, the grouting guide pipe and the ventilation pipe are arranged in a Wulff pattern and welded with the steel arch frame, the distance between the grouting guide pipe and the ventilation pipe and the surrounding rock surface of the collapse cavity is B, wherein B≤10cm, the grouting guide pipe and the ventilation pipe have the functions of grouting and venting;

[0022] S5: as the open TBM tunnels, after the Nth cycle collapse cavity support and the N+nth cycle collapse cavity support reach the wet spraying machine of the spraying area, the connection spraying concrete pipeline performs layered backfilling of concrete in the Nth cycle and the N+nth cycle collapse cavities through the grouting guide pipe, and then the wet spraying machine of the spraying area sprays concrete to the inner arc surface, the concrete layered backfilling sequence is from both sides to the middle and from the bottom to the top, the concrete layered backfilling height is at least higher than the highest point N of the steel arch frame, wherein N is a natural number not equal to zero, and the remaining space of the collapse cavity is filled with light materials;

[0023] S6: the Nth cycle and the N+nth cycle collapse cavity support sprays concrete to the designed inner arc surface.

[0024] IV: When the two sides of the shoe collapse, the treatment measures are:

[0025] When the collapse depth H < 0.5m, the collapse interval is laid with dense steel mesh, and the L1 emergency spray mixing system is layered to spray concrete to the design inner arc surface. The sprayed concrete strength is early strength concrete.

[0026] When the collapse depth H ≥ 0.5m, the collapse is temporarily filled with sandbags and sleepers, and the surface is laid with LxBxh (length x ring x thickness) strip steel plate. After the two sides of the shoe pass safely, the collapse to the wet spray machine in the spray mixing area is layered to spray concrete to the design inner arc surface.

[0027] Preferably, the construction steps of the steel mesh are as follows:

[0028] S1. Steel members such as steel mesh and connecting bars are concentratedly processed and formed in a steel field, and MSV multi-functional rubber-tyred vehicles are transported to a material lifting platform through a matched trolley after an open TBM;

[0029] S2. Start the material lifting platform, lift the steel members such as steel mesh and connecting bars to the rotating crane on the top of the L1 main beam, lift the rotating crane to the main beam, manually transport to the designated area for installation;

[0030] S3. The end of the Nth cycle steel mesh is overlapped and welded with the end of the N-1th cycle steel mesh, and the overlap length of the steel mesh is ≥ 30 times the diameter of the steel bar;

[0031] S4. The Nth cycle steel arch is assembled by the arch assembling machine, and the steel mesh is tightly attached to the rock surface;

[0032] The above-mentioned shoe and the steel mesh in the range below the bottom of the shoe are installed after the shoe passes through the position and before the wet spray machine in the spray mixing area sprays concrete.

[0033] Preferably, the installation steps of the steel arch are as follows:

[0034] S1. The steel arch is concentratedly processed in a steel field, and the MSV multi-functional rubber-tyred vehicles are transported to the inverted arch crane through a matched trolley after an open TBM, transported to the service beam through the inverted arch crane, and then transported to the arch assembling machine through the service beam;

[0035] S2. The steel arch is assembled by N segments of steel, the end of the Nth segment and the end of the N+1th segment are provided with connecting plates, and the whole is connected by M bolts. The arch assembling machine grabs the Nth segment with the grabbing head and rotates to release the installation position of the N+1th segment. Then the N+1th segment is installed and rotated. The N+nth segment is installed in turn, wherein M ≥ 4, and N is a natural number not equal to zero.

[0036] S3. The bracing device moves the assembled steel arch to the designated position, and the bracing is tightly attached to the rock surface and the reinforcing ribs are installed, the connecting plate nuts are tightened, and the joints of the Nth cycle and the N+1th cycle steel arches are staggered by at least 50%.

[0037] S4. The circumferential connecting ribs between the Nth cycle, the N+1th cycle and the N+nth cycle are installed, and the bracing boots and the connecting ribs at the bottom of the bracing boots are installed after the bracing boots pass and before the wet concrete spraying machine sprays concrete.

[0038] Preferably, the grouting sealing step is:

[0039] S1. The inverted arch blocks are pre-assembled in the precast yard in the forward direction, and the MSV multifunctional rubber wheel vehicle is used to transport the inverted arch blocks to the inverted arch block hoist through the open TBM supporting trolley, and the water stop strip is installed before the Nth inverted arch block is transported.

[0040] S2. The Nth inverted arch block installation area is cleaned, and the cushion block is installed, and the inverted arch block hoist is lifted and installed to the designated position through rotation.

[0041] S3. The bolts between the Nth inverted arch block and the N-1th inverted arch block are installed and tightened.

[0042] S4. The grouting pipeline is connected for grouting sealing.

[0043] The installation of the inverted arch block does not interfere with the construction of the steel mesh and the steel arch, and can be independently carried out.

[0044] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0045] 1. Three kinds of strong support methods for open TBM passing through the collapsed stratum in the fold belt and the support method when the bracing boots on both sides collapse are proposed, which are flexibly adopted according to the situation of the shield tail collapse and the size of the collapse cavity, thereby reducing the risk of initial support deformation or even collapse of the collapsed stratum due to insufficient initial support strength.

[0046] 2. For the open TBM without steel bar row function or insufficient steel bar row strength to resist the pressure of the collapsed debris, a dense row of welded strip steel plates is arranged at the outer wing plate of the upper steel arch, and the strip steel plates move backward to block the collapsed stone debris on the top of the shield as the open TBM advances, which is safe and reliable in construction, has low safety risk, and avoids damage to personnel and equipment caused by the collapsed stone debris in the advancing process, thereby improving the efficiency of the open TBM in the fold belt.

[0047] 3. For the open TBM rear matching trolley space is small, generally vehicle can not come to take self, open TBM in the process of tunneling steel arch, steel mesh, inverted arch block and other material transport using MSV multifunctional rubber-tyred vehicle to complete. MSV multifunctional rubber-tyred vehicle has the function of double-end driving, to and fro, convenient and fast, not restricted by the rear matching trolley clearance, provides reliable material transport guarantee for the tunneling of open TBM. BRIEF DESCRIPTION OF DRAWINGS

[0048] The drawings described herein are intended to provide further understanding of the embodiments of the present application, form a part of the present application, and do not constitute a limitation of the embodiments of the present application. In the drawings:

[0049] Figure 1 is a flowchart of the present application;

[0050] Figure 2 is a schematic diagram of the open TBM in the embodiments of the present application;

[0051] Figure 3 is an enlarged view of A in the schematic diagram of the open TBM in the embodiments of the present application;

[0052] Figure 4 is an enlarged view of B in the schematic diagram of the open TBM in the embodiments of the present application;

[0053] Figure 5 is an enlarged view of C in the schematic diagram of the open TBM in the embodiments of the present application;

[0054] Figure 6 is a schematic diagram of the anchor rod drilling machine of the open TBM in the embodiments of the present application;

[0055] Figure 7 is a schematic diagram of the left and right side support shoes of the open TBM in the embodiments of the present application;

[0056] Figure 8 is a schematic diagram of the MSV multifunctional rubber-tyred vehicle in the embodiments of the present application;

[0057] Figure 9 is a cross section of the continuous belt conveyor in the embodiments of the present application Figure I ;

[0058] Figure 10 is a cross section of the continuous belt conveyor in the embodiments of the present application Figure II ;

[0059] Figure 11 is a schematic diagram of the 0.5m-2m support of the collapsed cavity in the embodiments of the present application;

[0060] Figure 12 is a schematic diagram of the support of the 2m and above depth of the collapsed cavity in the embodiments of the present application.

[0061] Figure: 1- cutter head, 2- shield, 3- arch assembly machine, 4- anchor rod drill, 5- emergency spray mixing system, 6- support shoe, 7- rear support, 8- inverted arch block, 9- inverted arch crane, 10- rotary crane, 11- material lifting platform, 12- wet spraying machine in the spraying mixing area, 13- No. 1 trolley master control room, 14- concrete delivery pump, 15- concrete tank, 16- concrete tank crane, 17- MSV multifunctional rubber-tyred vehicle, 18- continuous belt conveyor, 19- concrete layered backfill, 20- grouting pipe, 21- air vent pipe, 22- sprayed concrete, 23- steel arch, 24- steel mesh, 25- strip steel member, 25- connecting rib, 26- strip steel plate, 27- lightweight material, 28- service beam. DETAILED DESCRIPTION

[0062] In order to make the object, technical scheme and advantages of the present application clearer, further detailed description will be given below in combination with examples and drawings. The schematic embodiments of the present application and their descriptions are only used to explain the present application, and do not limit the present application. It should be noted that the present application has been in the actual research and development stage.

[0063] As shown in Figures 1-12 An open type TBM full-face tunneling machine shield tail top collapse construction method, comprising the following steps:

[0064] Detect the collapse cavity depth caused by the upper collapse of the support shoe, and take different strong support measures according to different depths and positions, as follows:

[0065] I: When the collapse forms a collapse cavity depth H < 0.5m in the tunneling process above the top of the shield tail support shoe, the disposal measures of the collapse cavity are:

[0066] After the Nth cycle tunneling is completed, the shield tail is removed to clean the internal slag of the collapse cavity, the L1 area emergency spray mixing system performs initial spraying of the exposed surrounding rock of the Nth cycle collapse cavity, the steel mesh is laid, and the Nth cycle steel arch is installed. The Nth cycle steel arch and the Nth-1 cycle steel arch are firmly welded with the ring-shaped connecting rib staggered, the concrete is sprayed to the designed inner arc surface by the wet spraying machine in the spraying mixing area, the distance between the ring-shaped connecting rib of the Nth cycle steel arch and the Nth-1 cycle steel arch is B, and B≤100cm, and the distance L between the Nth cycle steel arch and the Nth-1 cycle steel arch is equal to the tunneling distance L' of the open type TBM per cycle;

[0067] II: When the collapse forms a collapse cavity depth 0.5m≤H<2m in the tunneling process above the top of the shield tail support shoe, the disposal measures are:

[0068] S1: After the Nth cycle of the shield tail is removed, the inside of the collapsed cavity is cleaned, and the L1 area emergency shotcrete system sprays shotcrete to seal the Nth cycle of the collapsed cavity, n layers of dense steel mesh are laid, the Nth cycle of the steel arch is installed, and the connecting rib between the Nth cycle of the steel arch and the N-1th cycle of the steel arch is replaced by a strip-shaped steel member, wherein n≥2. The length of the strip-shaped steel member is equal to the distance between the Nth cycle of the steel arch and the N-1th cycle of the steel arch, and the strip-shaped steel member can be an HW-shaped steel or a channel steel. The circumferential spacing of the steel arch is B, and B≤80cm;

[0069] S2: The grouting pipe and the air pipe are installed in the Nth cycle of the collapsed cavity, the grouting pipe and the air pipe are arranged in a plum blossom shape and welded to the Nth cycle of the steel arch, the distance between the grouting pipe and the air pipe and the top surrounding rock surface of the collapsed cavity is B, wherein B≤10cm, and the grouting pipe and the air pipe have the functions of grouting and air permeation;

[0070] S3: The tail of the grouting pipe and the air pipe is blocked, the L1 area emergency shotcrete system sprays shotcrete to support the Nth cycle of the collapsed cavity, and the thickness of the sprayed shotcrete is≥10cm;

[0071] S4: As the open TBM advances, after the Nth cycle of the collapsed cavity support reaches the wet shotcrete machine, the connecting shotcrete pipeline passes through the grouting pipe to perform layered backfilling of concrete in the Nth cycle of the collapsed cavity to the top of the collapsed cavity, and then the wet shotcrete machine in the shotcrete area is used to spray shotcrete to the inner arc surface. The sequence of layered backfilling of concrete is from both sides to the middle and from the bottom to the top.

[0072] S5: The monitoring equipment is used to detect the density, and whether grouting is needed is determined according to the monitoring results, and continuous monitoring and measurement are performed.

[0073] III: When the depth H of the collapsed cavity formed during the excavation of the range above the top of the shield tail support shoe is greater than 2m, and the surrounding rock of the shield tail continuously collapses and falls off during the excavation process, the treatment measures are:

[0074] S1: A strip-shaped steel plate is used to replace the steel mesh, after the Nth cycle of the steel arch is installed, a strip-shaped steel plate is welded circumferentially and densely on the outer wing plate of the Nth cycle of the steel arch, the size of the strip-shaped steel plate is L×B×h (length×circumferential direction×thickness), wherein L is equal to the length of the open TBM excavation process, B is determined by the outer arc of the steel arch, h≤8mm, one end of the length direction of the strip-shaped steel plate is welded at the outer wing plate of the Nth cycle of the steel arch, and the other end extends into the inside of the open TBM shield and closely contacts the outer wing plate of the N+1th cycle of the steel arch pre-installed on the inside of the shield.

[0075] The circumferential arc range of the end of the strip-shaped steel plate is determined according to the collapse degree of the surrounding rock of the shield tail;

[0076] S2: When the open TBM is excavated to the N+1 cycle, the strip steel plate and the pre-installed N+1 cycle steel arch are slowly taken out of the inside of the shield, the falling stones at the tail of the shield are intercepted, after the N+1 cycle excavation is completed, the arch assembling machine tightens the N+1 cycle steel arch to make it close to the surrounding rock with the strip steel plate, and the strip steel plate and the outer flange of the arch are welded firmly, and the strip steel plate and the steel arch of the N+2 cycle and the N+n cycle are completed in turn, 1 / 2 of the outer flange plate of the N+n cycle steel arch is welded with the end of the strip steel plate;

[0077] S3: After S2 is completed, a plurality of strip steel members are welded firmly between the N+n cycle steel arch and the N cycle steel arch, the strip steel member can be HW steel or channel steel, and the interval B is less than or equal to 60 cm;

[0078] S4: The N+n cycle and the N cycle strip steel plate part is punched, and the grouting pipe and the air pipe are installed, the grouting pipe and the air pipe are arranged in a Wulff shape and welded with the steel arch, the distance between the grouting pipe and the air pipe and the surrounding rock surface of the collapsed cavity is B, wherein B is less than or equal to 10 cm, and the grouting pipe and the air pipe have the functions of grouting and air exhaust;

[0079] S5: With the excavation of the open TBM, after the N cycle collapsed cavity support and the N+n cycle collapsed cavity support reach the wet spraying machine of the spraying area, the connection spraying concrete pipeline performs layered backfilling of concrete in the N cycle and the N+n cycle collapsed cavities through the grouting pipe, and then the wet spraying machine of the spraying area sprays concrete to the inner arc surface, the concrete layered backfilling sequence is from both sides to the middle and from the bottom to the top, the concrete layered backfilling height is at least higher than the highest point N of the steel arch, wherein N is a natural number not equal to zero, and the remaining space of the collapsed cavity is filled with light material;

[0080] S6: The N cycle and the N+n cycle collapsed cavity support sprays concrete to the designed inner arc surface.

[0081] IV: When the collapsed cavities are at both sides of the supporting shoe part, the treatment measures are:

[0082] When the collapsed cavity depth H is less than 0.5 m, the dense steel mesh is laid at intervals between the collapsed cavities, and the layered sprayed concrete is sprayed to the designed inner arc surface by the emergency spraying system in the L1 area, and the sprayed concrete strength is early strength concrete;

[0083] When the collapsed cavity depth H is greater than or equal to 0.5 m, sandbags and sleepers are used for temporary filling at the collapsed cavities, and L×B×h (length×circumferential direction×thickness) strip steel plates are laid on the surface, after the supporting shoes at both sides pass safely, the layered sprayed concrete is sprayed to the designed inner arc surface from the collapsed cavities to the wet spraying machine of the spraying area.

[0084] Preferably, the construction steps of the steel mesh are as follows:

[0085] S1. Steel reinforcement mesh, connecting rod and other steel components are centrally processed and formed in a steel reinforcement field, and are transported to a material lifting platform by an MSV multi-functional rubber-tyred vehicle via a matched trolley behind an open TBM;

[0086] S2. The material lifting platform is started, and the steel reinforcement mesh, connecting rod and other steel components are lifted to a rotary crane on the top of the L1 main beam, lifted to the main beam, manually transported to a designated area for installation;

[0087] S3. The end of the Nth cycle steel reinforcement mesh is overlapped and welded with the end of the (N-1)th cycle steel reinforcement mesh, and the overlapping length of the steel reinforcement mesh is greater than or equal to 30 times the diameter of the steel reinforcement;

[0088] S4. The Nth cycle steel arch is assembled by an arch assembling machine, and the steel reinforcement mesh is tightly attached to the rock surface by the arch.

[0089] The steel reinforcement mesh in the range below the bottom of the supporting shoe and the supporting shoe is installed before the concrete is sprayed by the wet spraying machine in the spraying area after the supporting shoe passes through the position.

[0090] Preferably, the steps of installing the steel arch are as follows:

[0091] S1. The steel arch is centrally processed in a steel reinforcement field, and is transported to the inverted arch crane by an MSV multi-functional rubber-tyred vehicle via a matched trolley behind an open TBM, transported to the service beam by the inverted arch crane, and then transported to the arch assembling machine by the service beam;

[0092] S2. The steel arch is assembled by N segments of steel, a connecting plate is arranged at the end of the Nth segment and the (N+1)th segment, and the whole is connected by M bolts, the Nth segment is grabbed and rotated by the arch assembling machine, the installation position of the (N+1)th segment is released, the (N+1)th segment is installed and rotated, and the N+nth segment is installed in turn, wherein M is greater than or equal to 4, and N is a natural number not equal to zero;

[0093] S3. The assembled steel arch is moved to a designated position by the supporting device, and is tightly attached to the rock surface and installed with the reinforcing ribs, and the nut of the connecting plate is tightened, and the joint of the Nth cycle and the (N+1)th cycle steel arch is staggered by at least 50%;

[0094] S3. The circumferential connecting rod between the Nth cycle, the (N+1)th cycle and the (N+n)th cycle is installed, and the supporting shoe and the connecting rod at the bottom of the supporting shoe are installed before the concrete is sprayed by the wet spraying machine in the spraying area after the supporting shoe passes through the position.

[0095] Preferably, the grouting and plugging steps are as follows:

[0096] S1. The inverted arch block is centrally and forwardly prefabricated in a prefabrication field, and is transported to the inverted arch crane by an MSV multi-functional rubber-tyred vehicle via a matched trolley behind an open TBM, and the Nth inverted arch block is installed with a water stop before being transported;

[0097] S2. Clean the installation area of ​​the Nth inverted arch block, install the pad block, and use the inverted arch crane to lift and rotate the inverted arch block to the designated position;

[0098] S3. Install and tighten the bolts between the Nth and (N-1)th inverted arch blocks;

[0099] S4. Connect the grouting pipeline for grouting and sealing;

[0100] The installation of the aforementioned inverted arch blocks does not interfere with the construction of the steel mesh and steel arch frame, and can be carried out independently. Example

[0101] like Figures 2 to 12 As shown, a 22.13km long tunnel in Xinjiang is located in a high-altitude and cold region. The tunnel adopts a "3 tunnels + 4 shafts" design scheme. The central pilot tunnel is excavated using the open-type TBM method, with a designed excavation diameter of 8430mm and a total machine length of 285m. This equipment has the functions of injection and open-type excavation, so the shield 2 is extended to 10m and the design of the steel reinforcement row is eliminated.

[0102] The open-face TBM at the tunnel exit advanced 10.801 km, successively traversing moderately weathered granite porphyry, marble interbedded with sandy slate, and granite. It traversed 3576 m of the influence zone of the Central Tianshan Fold, primarily consisting of marble interbedded with sandy slate. The harder rock exhibited a blocky, mosaic-like structure. During the process, 54 collapses occurred, all at the top of the six support shoes on both sides. The largest collapse cavity measured 13 m × 7.3 m × 6 m (longitudinal × circumferential × depth), accompanied by slight jamming. The cavity repair took 7 days.

[0103] In this embodiment, the open-type TBM includes a cutterhead 1, a shield 2, an arch frame assembly machine 3, an anchor drilling rig 4, an emergency shotcrete system 5, a support shoe 6, a rear support 7, an inverted arch block 8, an inverted arch crane 9, a rotating crane 10, a material lifting platform 11, a wet shotcrete machine for the shotcrete area 12, a main control room for trolley No. 1 13, a concrete delivery pump 14, a concrete hopper 15, a concrete hopper crane 16, an MSV multi-functional rubber-tired vehicle 17, a continuous belt conveyor 18, a layered concrete backfilling system 19, a grouting duct 20, a vent pipe 21, shotcrete 22, a steel arch frame 23, a steel mesh 24, strip steel components 25, connecting bars 26, strip steel plates 27, lightweight materials 28, and service beams 29.

[0104] This embodiment represents the largest collapse cavity among the 54 collapses. The collapse occurred at the top of the two side support boots 6, and the cavity measured 13m × 7.3m × 6m (longitudinal × circumferential × depth), accompanied by a slight jamming.

[0105] Since the depth of the collapsed cavity exceeded 2m, the third type of strong support method was used, and the steps are as follows:

[0106] S1: replace the steel mesh 24 with a strip steel plate 26, after the installation of the Nth cycle steel arch 23, weld the strip steel plate 26 on the outer wing plate of the Nth cycle steel arch 23, the size of the strip steel plate 26 is LxBxh (length x ring x thickness), wherein L is equal to the open TBM tunneling distance, B is determined by the outer arc of the steel arch 23, h≤8mm, one end of the strip steel plate 26 is welded on the outer wing plate of the Nth cycle steel arch 23, and the other end extends into the inside of the open TBM shield 2 and is in close contact with the outer wing plate of the N+1th cycle steel arch 23 previously installed inside the shield 2.

[0107] The ring arc range of the end of the strip steel plate 26 is determined according to the collapse degree of the surrounding rock after the shield tail is pulled out;

[0108] S2: when the open TBM tunnels forward to the N+1th cycle, the strip steel plate 26 and the N+1th cycle steel arch 23 previously installed slowly pull out from the inside of the shield 2, intercept the falling stones of the shield tail, after the N+1th cycle tunneling is completed, the arch assembling machine 3 tightens the N+1th cycle steel arch 23 to make it in close contact with the strip steel plate 26 and the surrounding rock, and the strip steel plate 26 is welded firmly with the outer wing of the arch, and the strip steel plate 26 and the steel arch 23 of the N+2th cycle and the N+nth cycle are sequentially completed, 1 / 2 of the outer wing plate of the N+nth cycle steel arch 23 is welded with the end of the strip steel plate 26;

[0109] S3: after S2 is completed, a plurality of strip steel members 25 are welded firmly between the N+nth cycle steel arch 23 and the Nth cycle steel arch 23, the strip steel member 25 can be HW steel or channel steel, and the interval B≤60cm;

[0110] S4: the N+nth cycle and the Nth cycle strip steel plate 26 part is punched, and the grouting pipe 20 and the vent pipe 21 are installed, the grouting pipe 20 and the vent pipe 21 are arranged in a Wrench shape and welded with the steel arch 23, the distance between the grouting pipe 20 and the vent pipe 21 and the surrounding rock surface of the collapse cavity is B, wherein B≤10cm, the grouting pipe 20 and the vent pipe 21 have the functions of grouting and venting;

[0111] S5: with the tunneling of the open TBM, after the Nth cycle collapse cavity support and the N+nth cycle collapse cavity support to the wet spraying machine 12 of the spraying mixing area, the connection spraying concrete 22 pipeline performs layered backfilling 19 of concrete in the Nth cycle and the N+nth cycle collapse cavities through the grouting pipe 20, and then the wet spraying machine 12 of the spraying mixing area is used to spray concrete 22 to the inner arc surface, the sequence of the layered backfilling 19 of concrete is from both sides to the middle and from the bottom to the top, the height of the layered backfilling 19 of concrete is at least higher than the highest point N of the steel arch 23, wherein N is a natural number not equal to zero, and the remaining space of the collapse cavity is filled with light material 27;

[0112] S6: The Nth cycle, the Nth + n cycle collapse support shotcrete 22 to the design of the intrados, the above-mentioned continuous belt conveyor 18 is suspended in the roof directly above by mortar anchor rod with guide chain.

[0113] The construction steps of the above-mentioned reinforcing mesh 24 are as follows:

[0114] S1. Reinforcing mesh 24, connecting rod 25 and other steel components are processed and formed in the steel field, and MSV multifunctional rubber wheel vehicle 17 is transported to material lifting platform 11 by open TBM supporting trolley.

[0115] S2. Start the material lifting platform 11, lift the reinforcing mesh 24, connecting rod 25 and other steel components to the rotary crane 10 on the top of the L1 main beam, lift the rotary crane 10 to the main beam, and manually transport it to the designated area for installation.

[0116] S3. The end of the Nth cycle reinforcing mesh 24 is overlapped and welded with the end of the N-1th cycle reinforcing mesh 24. The overlap length of the reinforcing mesh 24 is greater than or equal to 30 times the diameter of the reinforcing bar.

[0117] S4. The Nth cycle steel arch 23 is assembled by arch assembly machine 3, and the reinforcing mesh 24 is tightly attached to the rock surface.

[0118] The above-mentioned supporting shoe 6 and the reinforcing mesh 24 in the range below the bottom of the supporting shoe 6 are installed after the supporting shoe 6 passes through this part and before the wet shotcrete machine 12 sprays concrete 22.

[0119] The installation steps of the above-mentioned steel arch 23 are as follows:

[0120] S1. The steel arch 23 is processed in the steel field, and the MSV multifunctional rubber wheel vehicle 17 is transported to the inverted arch crane 9 by the open TBM supporting trolley, transported to the service beam 28 by the inverted arch crane 9, and then transported to the arch assembly machine 3 by the service beam 28.

[0121] S2. The steel arch 23 is assembled by N segments of steel, and the Nth segment and the N+1th segment are connected by a connecting plate with M bolts to form a whole. The arch assembly machine 3 grabs the Nth segment and rotates to release the installation position of the N+1th segment, and then installs the N+1th segment and rotates. The N+n segments are installed in turn. Wherein M≥4, N is a natural number not equal to zero.

[0122] S3. The assembled steel arch 23 is moved to the designated position by the supporting device, and the supporting device is tightly attached to the rock surface and installed with the reinforcing rib. The Nth cycle and the N+1th cycle steel arch 23 joint is staggered by at least 50%.

[0123] S4. Install the ring connecting rib 25 between the Nth cycle, N+1th cycle, N+nth cycle. The supporting shoe 6, the supporting shoe 6 bottom connecting rib 25 is installed after the supporting shoe 6 past, before the wet concrete spraying machine 12 sprays the concrete 22

[0124] The above-mentioned grouting sealing step is:

[0125] S1. The inverted arch block 8 is precast in the precast field in the positive direction, and is transported to the inverted arch crane 9 by the MSV multifunctional rubber wheel car 17 through the open type TBM supporting trolley. The Nth inverted arch block 8 is installed with the water stop before being transported.

[0126] S2. The Nth inverted arch block 8 installation area is cleaned, and the cushion block is installed. The inverted arch crane 9 is hoisted and installed to the specified position through rotation.

[0127] S3. The bolt between the Nth inverted arch block 8 and the N-1th inverted arch block 8 is installed and tightened.

[0128] S4. The grouting pipeline is connected for grouting sealing.

[0129] The above-mentioned inverted arch block 8 installation does not interfere with the construction of the steel mesh 24, the profiled steel arch 23, the system anchor rod and the sprayed concrete 22, and can be independently carried out.

[0130] Finally, under the method described in the application, the treatment of the collapsed cavity takes 7 days, reduces the falling of the collapsed stone blocks and the damage to the mechanical equipment, improves the tunneling efficiency and improves the safety degree. The above-mentioned specific embodiments further specifically describe the purpose, technical scheme and beneficial effects of the application. It should be understood that the above-mentioned is only the specific embodiment of the application and is not used to limit the protection scope of the application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. An open type TBM full face tunnel boring machine shield tail top collapse construction method, characterized in that, The measures include the following: The depth of the collapse cavity caused by the upper collapse of the support shoe (6) is detected, and different support measures are taken according to different depths and positions, as follows: I: When the collapse forms a cavity with a depth H < 0.5m in the range above the top of the shield tail support shoe (6) during excavation, the disposal measure for the cavity is: After the Nth cycle of excavation is completed, the shield tail is withdrawn to clean the internal debris of the collapse cavity, the L1 emergency shotcrete system (5) sprays the exposed surrounding rock of the Nth cycle of collapse cavity with initial shotcrete (22) to close it, lays n layers of dense steel mesh (24), and installs the Nth cycle of steel arch (23), the Nth cycle of steel arch (23) and the N-1 cycle of steel arch (23) are firmly welded with ring-shaped connecting ribs (25) in staggered positions, and the Nth cycle of steel arch (23) and the N-1 cycle of steel arch (23) are sprayed with shotcrete (22) by the wet shotcrete machine (12) to the designed inner arc surface, the distance between the ring-shaped connecting ribs (25) between the Nth cycle of steel arch (23) and the N-1 cycle of steel arch (23) is B, and B≤100cm, the distance L between the Nth cycle of steel arch (23) and the N-1 cycle of steel arch (23) is equal to the excavation distance L' of the open TBM per cycle; II: When the collapse forms a cavity with a depth 0.5m≤H<2m in the range above the top of the shield tail support shoe (6) during excavation, the disposal measure for the cavity is: S1: After the Nth cycle of excavation is completed, the shield tail is withdrawn to clean the internal debris of the collapse cavity, the L1 emergency shotcrete system (5) sprays the exposed surrounding rock of the Nth cycle of collapse cavity with initial shotcrete (22) to close it, lays n layers of dense steel mesh (24), and installs the Nth cycle of steel arch (23), the Nth cycle of steel arch (23) and the N-1 cycle of steel arch (23) are firmly welded with ring-shaped connecting ribs (25) in staggered positions, and the Nth cycle of steel arch (23) and the N-1 cycle of steel arch (23) are sprayed with shotcrete (22) by the wet shotcrete machine (12) to the designed inner arc surface, the distance between the ring-shaped connecting ribs (25) between the Nth cycle of steel arch (23) and the N-1 cycle of steel arch (23) is B, and B≤100cm, the distance L between the Nth cycle of steel arch (23) and the N-1 cycle of steel arch (23) is equal to the excavation distance L' of the open TBM per cycle; S2: Install the grouting pipe (20) and the air pipe (21) in the Nth cycle of collapse cavity, the grouting pipe (20) and the air pipe (21) are arranged in a quincunx shape and welded with the Nth cycle of steel arch (23), the distance between the grouting pipe (20) and the air pipe (21) and the top surrounding rock of the collapse cavity is B, wherein B≤10cm, the grouting pipe (20) and the air pipe (21) have the functions of grouting and air permeation; S3: Block the tail of the grouting pipe (20) and the air pipe (21), the L1 emergency shotcrete system (5) sprays shotcrete (22) for the Nth cycle of collapse cavity support, the thickness of the sprayed shotcrete (22) is ≥10cm; S4: As the open TBM advances, after the Nth cycle of collapse cavity support reaches the wet shotcrete machine (12) in the shotcrete area, the connecting shotcrete (22) pipeline passes through the grouting pipe (20) to perform layered backfilling (19) of concrete in the Nth cycle of collapse cavity to the top of the collapse cavity, and then the wet shotcrete machine (12) in the shotcrete area is used to spray shotcrete (22) to the inner arc surface, the sequence of the layered backfilling (19) of concrete is from both sides to the middle and from the bottom to the top. S5: The monitoring device is used to detect the density, and whether grouting is needed is determined according to the monitoring result, and continuous monitoring is carried out; III: When the collapse forms a cavity with a depth H>2m in the range above the top of the shield tail support shoe (6) during tunneling, and the surrounding rock of the tail continuously collapses and falls off during tunneling, the treatment measures are: S1: A strip steel plate (26) is used to replace the steel mesh (24), after the installation of the Nth cycle steel arch (23) is completed, the strip steel plate (26) is welded in a dense ring around the outer wing plate of the Nth cycle steel arch (23), the size of the strip steel plate (26) is LxBxh, the length direction x the ring direction x the thickness, wherein L is equal to the tunneling distance of the open TBM, B is determined by the outer arc of the steel arch (23), h≤8mm, one end of the length direction of the strip steel plate (26) is welded at the outer wing plate of the Nth cycle steel arch (23), and the other end extends into the inner side of the open TBM shield (2) and closely contacts the outer wing plate of the N+1th cycle steel arch which is pre-installed on the inner side of the shield; The ring arc range of the end of the strip steel plate (26) is determined according to the collapse degree of the surrounding rock of the tail; S2: When the open TBM tunnels forward to the N+1th cycle, the strip steel plate (26) and the pre-installed N+1th cycle steel arch slowly come out of the inner side of the shield (2), intercept the falling stones of the tail, after the N+1th cycle tunneling is completed, the arch assembling machine supports the N+1th cycle steel arch to make it closely contact with the surrounding rock and the strip steel plate, and the strip steel plate and the outer wing of the arch are welded firmly, and the N+2th cycle, the N+nth cycle strip steel plate (26) and the steel arch (23) are completed in turn, 1 / 2 of the outer wing plate of the N+nth cycle steel arch (23) is welded with the end of the strip steel plate (26); S3: After S2 is completed, a plurality of strip steel members (25) are welded firmly between the N+nth cycle steel arch (23) and the Nth cycle steel arch (23), the strip steel member (25) is HW steel or channel steel, and the spacing B≤60cm; S4: The N+nth cycle and the Nth cycle strip steel plate (26) are punched, and the grouting pipe (20) and the air pipe (21) are installed, the grouting pipe (20) and the air pipe (21) are arranged in a Wrench shape and welded with the steel arch (23), the distance between the grouting pipe (20) and the air pipe (21) and the surrounding rock surface of the top of the cavity is B, wherein B≤10cm, the grouting pipe (20) and the air pipe (21) have the functions of grouting and air exhaust; S5: With the excavation of the open TBM, the Nth cycle collapse cavity support, the Nth+n cycle collapse cavity support to the wet spraying machine (12) in the spray mixing area, the connecting concrete spraying pipe through the grouting pipe (20) to the Nth cycle and the Nth+n cycle collapse cavity for concrete layered backfill (19), and then the wet spraying machine (12) in the spray mixing area sprays concrete (22) to the inner arc surface. The concrete layered backfill (19) sequence is from both sides to the middle and from the bottom to the top. The concrete layered backfill (19) height is at least higher than the highest point N of the steel arch (23), wherein N is a natural number not equal to zero. The remaining space of the collapse cavity is filled with light material (27) for compaction; S6: The Nth cycle and the Nth+n cycle collapse cavity support sprays concrete (22) to the designed inner arc surface; Ⅳ: When the collapse cavity occurs at the two side support boots (6), the treatment measures are: When the collapse cavity depth H < 0.5 m, lay the dense steel mesh (24) at intervals in the collapse cavity, and the L1 emergency spray mixing system (5) sprays concrete (22) to the designed inner arc surface in layers. The strength of the sprayed concrete (22) is early strength concrete; When the collapse cavity depth H ≥ 0.5 m, use sandbags and sleepers for temporary filling at the collapse cavity, and lay the strip steel plate (26) with the size of L x B x h, length x ring direction x thickness, on the surface. After the two side support boots (6) pass safely, spray concrete (22) to the designed inner arc surface in layers at the wet spraying machine (12) in the spray mixing area.

2. The construction method of claim 1, wherein, The construction steps of the steel mesh (24) are as follows: S1. The steel mesh (24) and the connecting steel (25) are processed and formed in the steel field, and the MSV multifunctional rubber wheel vehicle (17) transports them to the material lifting platform (11) through the open TBM supporting trolley; S2. Start the material lifting platform (11), lift the steel mesh (24) and the connecting steel (25) to the rotating crane (10) on the top of the L1 main beam, and manually transport them to the designated area for installation; S3. Lap and weld one end of the Nth cycle steel mesh (24) with one end of the N-1th cycle steel mesh (24). The lap length of the steel mesh (24) is greater than or equal to 30 times the diameter of the steel bar; S4. Assemble the Nth cycle steel arch (23) with the arch assembly machine (3), and make the steel mesh (24) tightly adhere to the rock surface by the support circle. The above-mentioned support boots (6) and the steel mesh (24) in the range below the bottom of the support boots (6) are installed after the support boots (6) pass through this part and before the wet spraying machine (12) in the spray mixing area sprays concrete (22).

3. The construction method of claim 1, wherein, The installation steps of the steel arch (23) are as follows: S1. The steel arch (23) is processed in the steel field, and the MSV multifunctional rubber wheel vehicle (17) transports it to the inverted arch crane (9) through the open TBM supporting trolley, and then to the service beam (28) through the inverted arch crane (9), and finally to the arch assembly machine (3) through the service beam (28); S2. The type steel arch (23) is assembled by N segments, the end of the Nth segment and the N+1th segment is provided with a connecting plate, and the whole is connected by M bolts, the arch assembling machine (3) grabs the Nth segment and rotates, releases the installation position of the N+1th segment, then installs the N+1th segment and rotates, and then installs the N+nth segment, wherein M≥4, and N is a natural number not equal to zero; S3. The supporting device moves the assembled type steel arch (23) to a specified position, supports the type steel arch (23) to be close to the rock surface and installs a reinforcing rib, tightens the connecting plate nut, and the joint of the Nth cycle and the N+1th cycle type steel arch (23) is staggered by at least 50%; S4. Install the circumferential connecting rib (25) between the Nth cycle, the N+1th cycle and the N+nth cycle, and install the connecting rib (25) after the supporting shoe (6) passes, and then spray the concrete (22) by the wet spraying machine (12).

4. The construction method of claim 1, wherein, The above grouting sealing step is: S1. The inverted arch block (8) is centrally and positively prefabricated in the prefabrication yard, is transported to the inverted arch crane (9) by the MSV multifunctional rubber wheel vehicle (17) through the open TBM supporting trolley, and the Nth inverted arch block (8) is provided with a water stop before being transported; S2. Clean the installation area of the Nth inverted arch block (8), install the cushion block, and install the inverted arch crane (9) to the specified position through rotation; S3. Install the bolt between the Nth inverted arch block (8) and the N-1th inverted arch block (8) and tighten it; S4. Connect the grouting pipeline to seal by grouting; The installation of the inverted arch block (8) does not interfere with the construction of the reinforcing mesh (24) and the type steel arch (23), and can be independently carried out.

Images