A structure and construction method for rapid assembly of mid-span beam segments

Abstract

The present invention discloses a structure and construction method for rapid assembly of mid-span beam segments, specifically relating to the technical field of on-site assembly of segmental beams, including segmental beams with multiple groups of prestressed pipes reserved, a notch reserved at one end of each segmental beam, an anchor plate pre-buried inside the notch, prestressed pipe holes and built-in grouting holes reserved on the anchor plate, and a through-wall hole reserved on the inner side wall of the notch; grouting does not affect the hoisting and splicing of the next segmental beam, the construction segments are connected end to end, and there is no need to seal the anchor head during grouting; an external grouting hole can also be reserved on the side wall of the notch at one end, and the built-in grouting hole passes through the through-wall hole, which also does not affect the hoisting and splicing of the next segmental beam during grouting, and can grout the prestressed pipe holes and the notch space in stages respectively. The construction method provided by the present invention is convenient, and the construction quality is more reliable. The sequential construction of section-by-section installation and section-by-section grouting is adjusted to a parallel construction method of section-by-section installation and section-by-section grouting, which greatly improves construction efficiency and shortens construction period.

Description

Technical Field

[0001] The present invention relates to the technical field of on-site assembly construction of bridge segmental beams, and in particular to a structure and a construction method for rapid assembly of mid-span segmental beams. Background Art

[0002] The prefabricated segmental assembly method is to prefabricate bridge segments in a prefabrication plant, then transport them to the site one segment at a time, and hoist them to the predetermined position by cantilever, span by span, or progressively. Then, prestressing is applied to connect the segments into a whole. Finally, the pier tops or mid-span wet joints are cast in situ using a hanging formwork to complete the bridge construction. The main construction methods are cantilever assembly method and span-by-span assembly method.

[0003] The installation of the mid-span beam segments was carried out using a balanced "T" symmetrical cantilever assembly method. The steps involved include: inspection, cleaning, and installation preparation at the beam segment prefabrication site; shipment of the beam segments; simultaneous lifting of the first pair of beam segments to the designated location by two overhead cranes; trial assembly of the beam segments; application of the epoxy resin adhesive layer; precise positioning of the first pair of beam segments; application of temporary prestressing; curing of the adhesive layer until solidified; application of the permanent internal prestressing tendons; vacuum grouting of the prestressing pipes; anchor sealing; longitudinal prestressing end capping; unhooking the crane and preparing for lifting the next pair of beam segments. The epoxy resin adhesive layer application process involves: cleaning the splicing surface → trial assembly and adjustment of the segments → epoxy resin preparation → application → splicing the segment beams → adhesive scraping and cleaning.

[0004] After the epoxy resin reaches the design strength, the prestressed tendons are tensioned. Prestressed tendons are assembled and assembled. The prestressed tendons construction process includes: preparation – testing of steel strands, anchors, and clips – unloading of steel strands → strand threading → jack installation → intelligent tensioning.

[0005] The main procedure for vacuum grouting prestressed pipes is as follows: After tensioning is complete, excess steel strands are cut with a grinding wheel cutter, leaving 3-5 cm of strands remaining. After the strands are removed, the anchor heads to be grouted are immediately sealed with cement mortar to ensure a dense seal. Grouting is performed within 48 hours of tensioning completion. Vacuum grouting technology is used. After vacuum grouting of the prestressed pipes is completed, longitudinal prestressing ends are capped.

[0006] The deep-buried anchor design results in a large longitudinal prestressing notch, requiring prompt end-capping after grouting. The existing end-capping process includes installing the end-capping formwork and pouring concrete. The end-capping concrete is C50 shrinkage-compensating concrete, which is vibrated and compacted with a vibrator during pouring, ensuring it is flush with the beam end face. The offset between the end-capping concrete and the beam body should not exceed 5mm. After pouring, the end-capping concrete requires prompt curing.

[0007] The longitudinal prestressing notch is located between the two segmental beam assembly surfaces. The current vacuum grouting of the prestressing pipes and the capping of the longitudinal prestressing notch severely impact the progress of segmental beam assembly, especially the curing after the end-capping concrete is poured. The currently common segmental beam assembly method involves sequential section-by-section prestressing, section-by-section grouting, and section-by-section installation, with all three steps being critical. The end-capping concrete, using C50 shrinkage-compensating concrete, also presents difficulties in pouring, with small amounts used each time, making mixing difficult, and the uneven end-capping surface affecting the matching installation between segmental beams. Summary of the Invention

[0008] In order to solve the problems encountered in the existing segmental beam construction process, the present invention provides: a structure for rapid assembly of mid-span segmental beams, comprising a segmental beam with multiple sets of prestressed pipes reserved, a notch reserved at one end of each segmental beam, an anchor plate embedded in the notch, prestressed pipe holes and built-in grout holes reserved on the anchor plate, and a through-wall hole reserved on the inner side wall of the notch;

[0009] A small circumferential groove is set on the outside of the mouth of the notch, and a ring-shaped aluminum alloy sheet is embedded in the corresponding position of the groove on the matching segment beam. The depth of the small groove is 3~4cm, and the aluminum alloy sheet protrudes 2cm from the plane of the segment beam.

[0010] Based on this structure, the present invention provides a construction method for rapid assembly of mid-span segmental beams, comprising the following steps: S1, hoisting multiple segmental beams using a bridge erection machine, wherein the multiple segmental beams include an Nth pier top segment block;

[0011] S2. Use the symmetrical cantilever assembly method to symmetrically hoist the N+1 and N-1 segment beams to the two ends of the Nth segment;

[0012] S3. Glue the segmental beams that have been hoisted into place. After completion, thread the steel strands and tension the prestressed steel strands.

[0013] S4. Continue to hoist the mutually symmetrical outer segment beams and glue them together with the inner segment. After gluing is completed, connect the grouting machine to the through-hole at one end of the inner segment that has completed step S3, and connect the through-hole at the other end to the vacuum machine to start the grouting operation.

[0014] S5. Repeat steps S3-S4. It should be noted that multiple sets of prestressed pipes are reserved inside the segmental beams. The beams of different segments in the construction section are connected with each other to complete the construction of the construction section.

[0015] On the basis of the above structure, the built-in slurry hole can be extended with a plastic tube and passed through the wall hole, and the outer end of the plastic tube is equipped with a valve; the side wall of the slot is also reserved for external slurry holes, which include a first slurry hole and a second slurry hole. The first slurry hole is arranged at the bottom of the inner side of the slot, and the second slurry hole is arranged at the top of the inner side of the slot. The first and second slurry holes are both connected to transparent steel wire tubes, and the outer ends of the transparent steel wire tubes are equipped with valves. Based on this structure, the present invention also provides a construction method for rapid assembly of mid-span beam segments, including the following specific steps:

[0016] S1. Using a bridge erection machine to hoist a multi-segment beam, wherein the multi-segment beam includes an Nth pier top segment block;

[0017] S2. Use the symmetrical cantilever assembly method to symmetrically hoist the N+1 and N-1 segment beams to the two ends of the Nth segment;

[0018] S3. Glue the segmental beams that have been hoisted into place. After completion, thread the steel strands and tension the prestressed steel strands.

[0019] S4. Use cement mortar to seal the anchor head that needs grouting, and use epoxy resin glue to seal the gap between the wall hole and the plastic pipe. After the sealing is completed, the built-in grouting holes, plastic pipes and prestressed pipe holes and prestressed pipes at both ends of the construction section form a fully enclosed space. Hoist the mutually symmetrical outer segment beams and glue them to the inner segment beams. After the gluing is completed, a closed space is formed at the notch of the inner construction section; connect the grouting machine to the plastic pipe that passes through the wall hole at one end of the inner segment that has completed step S3, and connect the plastic pipe that passes through the wall hole at the other end to the vacuum machine to start the grouting operation;

[0020] S5. Repeat steps S3-S4 until the segment splicing and prestressed pipe grouting operations in the construction section are completed;

[0021] S6. Carry out grouting operation on the closed space formed at the notch. Specifically, connect the transparent steel wire tube of the first slurry hole at one end of the notch at the head of the segment that needs grouting with the grouting machine, connect the second slurry hole in the middle with the first slurry hole of the next segment end to end, connect the second slurry hole at the tail of the segment with the vacuum machine, start the grouting operation, and finally complete the construction of this construction section.

[0022] Furthermore, the gluing treatment is specifically as follows: cleaning the joint surface, pasting the sealing ring, mixing the glue and applying the glue in sequence; during installation, filling the groove with epoxy resin, and the groove is tightly fitted with the aluminum alloy sheet.

[0023] Furthermore, the specific steps of the aforementioned grouting operation are:

[0024] Step 1: Start the vacuum pump to make the channel vacuum degree reach -0.08~-0.1MPa and keep it stable;

[0025] Step 2: Start the grouting machine and control the grouting pressure at 0.5~0.7Mpa to carry out the grouting operation. During the grouting process, the vacuum machine keeps working continuously.

[0026] Step 3: When slurry passes through the air filter of the vacuum machine, close the valve at the front end of the air filter, and then open the exhaust valve. When the cement slurry flows out of the exhaust valve smoothly and its consistency is equivalent to that of the pressed slurry, close all valves at the vacuum end and stabilize the pressure. The stabilization pressure should not be less than 0.5Mpa and the stabilization time should be 3 to 5 minutes. If the slurry pressure does not drop during the stabilization process, close the grouting machine and the valve at the grouting end to complete the grouting.

[0027] Step 4: Before the cement slurry loses fluidity, remove the external pipes and accessories and clean them.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] According to the first construction method of the present invention, the through-wall hole is set on the side wall of the slot. During the grouting operation, it does not affect the assembly construction of the next segment beam. The sequential construction of installation and grouting section by section is adjusted to a parallel construction method of installation section by section and grouting every other section, which shortens the construction period. After the front and rear segment beams are installed and matched, the end sealing material is injected, which solves the problem of mismatch between the end sealing concrete surface of the previous segment beam and the corresponding surface of the rear segment beam. At the same time, there is no need to seal the anchor head of the slot, and the space at the slot is directly merged together to form a closed space between the head and tail of the construction segment. The grouting method is used for end sealing, and the process of erecting the end sealing concrete formwork is eliminated, which solves the problem of mixing and pouring small-volume concrete. Grouting material is used instead of end sealing concrete to improve the density of the end sealing material.

[0030] According to the second construction method of the present invention, the through-wall hole, the first grouting hole, and the second grouting hole are all set on the side wall of the notch. During the grouting operation, the assembly construction of the next segment beam is not affected. The sequential construction of section-by-section installation and section-by-section grouting is adjusted to a parallel construction method of section-by-section installation and section-by-section grouting, which shortens the construction period. Grouting is carried out in two steps. The prestressed pipe hole and the built-in grouting hole form a closed space. The anchor head is first sealed and grouting is carried out. Finally, the space at all corresponding notches in the construction section is grouting. This also solves the problem of mixing and pouring small-volume concrete. The material requirements in the prestressed pipe hole are higher than those at the notch. The two-step grouting method can reduce costs.

[0031] 3. The groove pouring epoxy resin glue and pre-embedded aluminum alloy sheet plug-in technology are used to improve the airtightness of the overall enclosed space, achieve double sealing of the plane and facade, and solve the hidden danger of leakage on the splicing surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0033] Figure 1 It is a schematic diagram of the symmetrical cantilever assembly construction method of the present invention;

[0034] Figure 2 It is a projection view of the front of a single segment beam of the present invention;

[0035] Figure 3 This is a schematic diagram of a notch arrangement method of the present invention;

[0036] Figure 4 It is a schematic diagram of the connection relationship between the built-in slurry hole and the prestressed pipe hole of the present invention;

[0037] Figure 5 It is a schematic diagram of another arrangement of the notch of the present invention;

[0038] Figure 6 is a side sectional view of the notch of the present invention;

[0039] Figure 7 It is a schematic diagram of the connection mode of each hole under one construction mode of the present invention;

[0040] Figure 8 It is a schematic diagram of the connection mode of each hole when the grouting operation is performed on the closed space of the slot according to the present invention;

[0041] Figure 9 It is a construction method flow chart of the present invention;

[0042] Figure 10 It is another construction method flow chart of the present invention.

[0043] Among them, 1. Notch; 11. Anchor plate; 12. Prestressed pipe hole; 13. Built-in slurry hole; 14. Wall hole; 2. Groove; 3. Aluminum alloy sheet; 4. External slurry hole; 41. First slurry hole; 42. Second slurry hole. DETAILED DESCRIPTION

[0044] In order to make the purpose, features, and advantages of this application more obvious and easy to understand, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described below are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0045] refer to Figure 1-4 and Figure 6 A structure for rapid assembly of mid-span segmental beams, comprising segmental beams with multiple sets of prestressed pipes reserved, a notch 1 reserved at one end of each segmental beam, an anchor plate 11 embedded inside the notch 1, prestressed pipe holes 12 and built-in mortar holes 13 reserved on the anchor plate 11, and a through-wall hole 14 reserved on the inner wall of the notch 1;

[0046] A small circumferential groove 2 is set outside the mouth of the notch 1, and a ring-shaped aluminum alloy sheet 3 is embedded in the corresponding position of the groove 2 on the matching segment beam. The depth of the small groove 2 is 3 cm, and the aluminum alloy sheet 3 protrudes 2 cm from the plane of the segment beam.

[0047] refer to Figure 7 、 Figure 9 Based on this structure, the present invention provides a construction method for rapid assembly of mid-span segmental beams, comprising the following steps: S1, hoisting a multi-segmental beam using a bridge erection machine, wherein the multi-segmental beam includes an Nth pier top segment block, the segment block is not provided with a notch 1, and only a prestressed pipe is reserved;

[0048] S2. Use the symmetrical cantilever assembly method to symmetrically hoist the N+1 and N-1 segment beams to the two ends of the Nth segment;

[0049] S3. Glue the segmental beams that have been hoisted into place. After completion, thread the steel strands. This involves threading the strands from the notch 1 at one end of the construction section directly to the corresponding notch 1 at the other end, passing through all the segmental beams on the inside, and then performing prestressing.

[0050] S4. Continue to hoist the mutually symmetrical outer segment beams and glue them together with the inner segment. After the gluing is completed, connect the grouting machine to the wall hole 14 at one end of the inner segment that has completed step S3, and connect the wall hole 14 at the other end to the vacuum machine to start the grouting operation.

[0051] S5. Repeat steps S3-S4. It should be noted that multiple sets of prestressed pipes are reserved inside the segmental beams. The beams of different segments in the construction section are connected with each other to complete the construction of the construction section.

[0052] refer to Figure 1 、 Figure 2 、 Figure 4-6 On the basis of the above structure, the built-in slurry hole 13 can also be extended with a plastic tube and passed through the wall hole 14. A valve is installed on the outside of the plastic tube. An external slurry hole 4 is also reserved on the side wall of the slot 1 at one end. The external slurry hole 4 includes a first slurry hole 41 and a second slurry hole 42. The first slurry hole 41 is arranged at the bottom of the inner side of the slot 1, and the second slurry hole 42 is arranged at the top of the inner side of the slot 1. The first slurry hole 41 and the second slurry hole 42 are both connected to a transparent steel wire tube, and a valve is installed on the outside of the transparent steel wire tube. Figure 8 、 Figure 10 On the basis of this structure, the present invention also provides a construction method for rapid assembly of mid-span beam segments, comprising the following specific steps:

[0053] S1. hoisting a plurality of segmental beams using a bridge erection machine, wherein the plurality of segmental beams includes an Nth segmental beam;

[0054] S2. Use the symmetrical cantilever assembly method to symmetrically connect the N+1 and N-1 segment beams to the two ends of the Nth segment;

[0055] S3. For the assembled segmental beams, carry out steel strand threading, gluing and prestressing.

[0056] S4. Use cement mortar to seal the anchor head of the notch 1 that needs grouting. After the sealing is completed, the built-in slurry holes 13, the hose and the prestressed pipe hole 12 at both ends form a fully enclosed space. Connect the grouting machine to the hose that passes through the wall hole 14 at one end, and connect the other end of the hose to the vacuum pump to start the grouting operation. At the same time, hoist the mutually symmetrical outer segmental beams and complete the assembly with the inner segmental beam. When the assembly is completed, the corresponding notches 1 form a fully enclosed space.

[0057] S5. Repeat steps S3-S4 until the segment splicing and prestressed pipe grouting operations in the construction section are completed;

[0058] S6. Perform grouting operations on the fully enclosed space formed at the corresponding notches 1. Specifically, connect the transparent steel wire hose of the first slurry hole 41 at one end of the notch 1 at the head of the segment that needs grouting to the grouting machine, connect the second slurry hole 42 in the middle with the first slurry hole 41 of the next segment end to end, connect the second slurry hole 42 at the tail of the segment to the vacuum machine, start the grouting operation, and finally complete the construction of this construction section.

[0059] Specifically, the gluing process is as follows: cleaning the joint surface, pasting the sealing ring, mixing the glue and applying the glue in sequence; during installation, the annular groove 2 is filled with epoxy resin, and the annular groove 2 is tightly fitted with the aluminum alloy sheet 3, so that the notch 1 is completely closed.

[0060] Specifically, the specific steps of the grouting operation mentioned above are:

[0061] Step 1: Start the vacuum pump to make the channel vacuum degree reach -0.1MPa and keep it stable;

[0062] Step 2: Start the grouting machine and control the grouting pressure at 0.7 MPa to carry out the grouting operation. During the grouting process, the vacuum machine keeps working continuously.

[0063] Step 3: When slurry passes through the air filter of the vacuum machine, close the valve at the front end of the air filter, and then open the exhaust valve. When the cement slurry flows out of the exhaust valve smoothly and its consistency is equivalent to that of the pressed slurry, close all valves at the vacuum end and stabilize the pressure. The stabilization pressure should not be less than 0.5Mpa and the stabilization time should be 5 minutes. If the slurry pressure does not drop during the stabilization process, close the grouting machine and the valve at the grouting end to complete the grouting.

[0064] Step 4: Before the cement slurry loses fluidity, remove the external pipes and accessories and clean them.

[0065] It should be noted that: since the through-wall hole 14, the first grouting hole 41 and the second grouting hole 42 are all arranged on the side wall of the slot 1, during actual construction, the prestressed pipe and the slot 1 space within the construction section can be selectively grouted.

[0066] To avoid misunderstanding, here are some specific examples of the hoisting, splicing and grouting process:

[0067] First, hoist the Nth segment block, then hoist the N+1 and N-1 segment beams, and glue them to the Nth segment block. After completion, the steel strands are passed through the left notch 1 of the N-1 segment, through the N segment, and out from the corresponding notch 1 on the right end of the N+1 segment, and then prestressing is carried out; next, hoist the N+2 and N-2 segment beams to the outside of the construction section and glue them to the inner segment beams (that is, the N+2 segment is on the right side of the N+1 segment and glued to the N+1 segment, and the N-2 segment is on the N-2 segment). (The left side of section 1 is glued to section N-1.) Once completed, the N-1, N, and N+1 segmental beams are wrapped between sections N-2 and N+2. The prestressed pipes and notches 1 between them are sealed, leaving only the through-wall holes 14 penetrating the side walls at both ends. At this point, grouting can be performed on the enclosed spaces of sections N-1, N, and N+1. This grouting operation does not affect the hoisting and gluing of sections N+2 and N-2, or even the segments beyond. This process can be repeated, expediting construction. Similarly, the second construction method of grouting the slot 1 space and the prestressed pipe separately is similar to the above process. The difference is that the hard pipe passing through the wall hole 14 is only used to grout the prestressed pipe, and the space of the slot 1 is grouting by connecting the first slurry hole 41 and the second slurry hole 42 end to end, which solves the problem of mixing and pouring small-volume concrete. The material requirements in the prestressed pipe are higher than those at the slot 1. This two-step grouting method can reduce costs and is more flexible in the construction process.

[0068] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A structure for rapid assembly of mid-span segmental beams, comprising segmental beams with multiple sets of prestressed pipes reserved, characterized by: A notch is reserved at one end of each segment beam, an anchor plate is embedded in the notch, prestressed pipe holes and built-in slurry holes are reserved on the anchor plate, and a through-wall hole is reserved on the inner wall of the notch; A small circumferential groove is provided on the outer side of the mouth of the notch, and an annular aluminum alloy sheet is embedded in the corresponding position of the groove on the matching segment beam. The depth of the groove is 3-4 cm, and the aluminum alloy sheet protrudes 2 cm from the plane of the segment beam. The built-in slurry hole is extended with a plastic pipe and passed through the wall hole. The outer end of the plastic pipe is equipped with a valve. An external slurry hole is also reserved on the side wall of the slot. The external slurry hole includes a first slurry hole and a second slurry hole. The first slurry hole is arranged at the bottom of the inner side of the slot, and the second slurry hole is arranged at the top of the inner side of the slot. The first slurry hole and the second slurry hole are both connected with a transparent steel wire tube. The outer end of the transparent steel wire tube is equipped with a valve. The plastic pipe passing through the wall hole is only used to grout the prestressed pipe, and the space of the slot is grouting by connecting the first slurry hole and the second slurry hole end to end.

2. A construction method for rapid assembly of mid-span beam segments, comprising the structure for rapid assembly of mid-span beam segments according to claim 1, characterized in that: The specific steps include: S1. Using a bridge erection machine to hoist a multi-segment beam, wherein the multi-segment beam includes an Nth pier top segment block; S2. Use the symmetrical cantilever assembly method to symmetrically hoist the N+1 and N-1 segment beams to the two ends of the Nth segment; S3. Glue the segmental beams that have been hoisted into place. After completion, thread the steel strands and tension the prestressed steel strands. S4. Use cement mortar to seal the anchor head that needs grouting, and use epoxy resin glue to seal the gap between the wall hole and the plastic pipe. After the sealing is completed, the built-in grouting holes, plastic pipes and prestressed pipe holes and prestressed pipes at both ends of the construction section form a fully enclosed space. Hoist the mutually symmetrical outer segment beams and glue them to the inner segment beams. After the gluing is completed, a closed space is formed at the notch of the inner construction section; connect the grouting machine to the plastic pipe that passes through the wall hole at one end of the inner segment that has completed step S3, and connect the plastic pipe that passes through the wall hole at the other end to the vacuum machine to start the grouting operation; S5. Repeat steps S3-S4 until the segment splicing and prestressed pipe grouting operations in the construction section are completed; S6. Carry out grouting operation on the closed space formed at the notch. Specifically, connect the transparent steel wire tube of the first slurry hole at one end of the notch at the head of the segment that needs grouting with the grouting machine, connect the second slurry hole in the middle with the first slurry hole of the next segment end to end, connect the second slurry hole at the tail of the segment with the vacuum machine, start the grouting operation, and finally complete the construction of this construction section.

3. A construction method for rapid assembly of mid-span segmental beams according to claim 2, characterized in that: The gluing process specifically includes: cleaning the joint surface, pasting the sealing ring, mixing the glue and applying the glue in sequence; during installation, filling the groove with epoxy resin, and the groove is tightly fitted with the aluminum alloy sheet.

4. A construction method for rapid assembly of mid-span segmental beams according to claim 2, characterized in that: The specific steps of the grouting operation are: Step 1: Start the vacuum pump to make the channel vacuum degree reach -0.08~-0.1MPa and keep it stable; Step 2: Start the grouting machine and control the grouting pressure at 0.5~0.7Mpa to carry out the grouting operation. During the grouting process, the vacuum machine keeps working continuously. Step 3: When slurry passes through the air filter of the vacuum machine, close the valve at the front end of the air filter, and then open the exhaust valve. When the cement slurry flows out of the exhaust valve smoothly and its consistency is equivalent to that of the pressed slurry, close all valves at the vacuum end and stabilize the pressure. The stabilization pressure should not be less than 0.5Mpa and the stabilization time should be 3 to 5 minutes. If the slurry pressure does not drop during the stabilization process, close the grouting machine and the valve at the grouting end to complete the grouting. Step 4: Before the cement slurry loses fluidity, remove the external pipes and accessories and clean them.

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