Construction method for layered pouring of tunnel secondary lining trolley
By using a layered pouring system and multi-stage pump pressure control, the problem of insufficient construction continuity in tunnel secondary lining construction was solved, achieving an efficient and continuous pouring process and reducing construction risks and quality defects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-03-31
AI Technical Summary
In the current construction of tunnel secondary lining, the lack of continuous control during the layered pouring process can easily lead to construction hazards and potential failures, especially uneven pouring and positional imbalance.
A layered pouring system is adopted, including multi-stage injection pumps and concrete outlet components. Through precise positioning, layered pouring, and dynamic adjustment of formwork position difference, combined with pressure control of multi-stage pumps and concrete slurry fluidity testing, the continuity and quality of pouring are ensured.
It significantly improved construction efficiency, reduced the arch void rate and leakage rate, enhanced structural quality and construction continuity, and reduced construction risks.
Smart Images
Figure CN121760741A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of tunnel secondary lining construction technology, and in particular to a construction method for layered pouring of tunnel secondary lining using a trolley. Background Technology
[0002] After the initial tunnel construction is completed, a lining is installed as a stable and durable permanent lining, called the secondary lining. The thickness of the secondary lining is determined according to the actual design. After the outer layer of the tunnel soil layer is completed with anchor sprayed concrete and waterproofing is completed, a secondary lining can be made. The secondary lining is the inner structure of the composite lining and together with the initial support (outer layer sprayed anchor support) forms the tunnel support system. The secondary lining construction process typically consists of reinforced concrete or plain concrete, including steps such as formwork erection, rebar installation, and concrete pouring. Its main functions include enhancing overall stability, preventing deformation and damage, and ensuring traffic safety. Another characteristic of the secondary lining construction process is that the "invert arch spacing" specification is strictly followed during construction, and the stress system is formed through the closure of the invert arch. Clearly, the tunnel lining is a key aspect of tunnel quality control, and the construction quality of the tunnel lining is related to various types of tunnel failures, such as high-level defects like cracks and water seepage. These defects are not easy to repair and require quality control during construction, such as ensuring the synchronicity and uniformity of concrete pouring, in order to eliminate potential hazards from the construction period. Currently, in the pouring of secondary lining using a construction trolley, a layered pouring method is adopted. That is, the pouring situation exposed by the working window of the formwork is considered as one layer. After the working window is closed, pouring continues. As pouring continues, the initial pouring position will bear the self-weight of the concrete slurry, requiring continuous increase in the pouring pump pressure. However, as the pressure increases, the closer the formwork is to the arch, the worse the control of the continuously pressurized pouring pump becomes as the working window is closed. This easily leads to uneven pouring and imbalance of position difference on both sides of the synchronous pouring. The time required for observation through the working window and auxiliary vibration guidance increases, creating additional construction hazards and seriously affecting the continuity of secondary lining pouring construction. Summary of the Invention
[0003] The present invention aims to solve the technical problem that the existing secondary lining pouring construction process has insufficient control over the construction continuity, which easily leads to construction hazards and potential failures. It provides a construction method for layered pouring of tunnel secondary lining using a trolley.
[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A construction method for layered casting of tunnel secondary lining using a trolley includes: Step S1: Before the secondary lining trolley 10 is in place, check whether there are hollow areas in the support layer 20 of the pouring section. A tunnel laser scanner was used to detect whether the tunnel cross section encroached on the secondary lining limit line, and the installation of the tunnel chamber embedded parts was completed to confirm that the conditions for secondary lining construction were met. Step S2: Check the curvature and flatness of the panel 100 of the secondary lining trolley 10, and complete the grinding, degreasing and rust prevention of the panel 100, as well as the tunnel measurement control points, and determine the center points of the front and rear ends of the secondary lining pouring section. The track 30 for installing the secondary lining trolley 10 is precisely positioned and matched to the track 30 by setting a group of markers on the secondary lining pouring section. Step S3: After the secondary lining trolley 10 is moved into place, the secondary lining trolley 10 is fixed by the secondary lining trolley braking device, and multiple screw jacks 40 are used to tightly attach the panel 100 to the formwork 50 and the concrete surface of the pouring section support layer 20. The panel 100 should have an overlap or butt joint with the concrete of the previous construction module of at least 10cm. Step S4, the concrete pouring process, uses a layered pouring system 1000 to pour concrete using multiple delivery pumps, so that the left and right height difference of the pouring template cavity 501 is less than 50cm. The vertical distance between the concrete outlet and the pouring surface is controlled within 1.2m using the concrete outlet component 2000 to prevent concrete segregation. Step S5: During the concrete pouring process, whenever an additional set of the conveying pumps is started, pressure is applied to one side of the multiple 40 threaded jacks to counteract the deformation of the formwork. The layered multi-stage pouring system is connected to the main concrete injection pipe 102 at the low-level interface 101.
[0005] Furthermore, the layered casting system 1000 includes: The main concrete pouring equipment V1 is connected to the main concrete injection pipe 102 via two sets of primary injection pumps 110. A primary pressure detector P1 is installed on the main concrete injection pipe 102.
[0006] Furthermore, the panel 100 has windows arranged from bottom to top, and the windows include: Working window 401 is used to observe the grouting process and can be closed based on the grouting process and construction progress. Auxiliary infusion window 402, equipped with a secondary infusion connector; The panel 100 is configured with multiple virtual planning levels from bottom to top; The work window 401 and auxiliary injection window 402 of each virtual planning level are arranged alternately.
[0007] Furthermore, the layered casting system 1000 also includes: The secondary irrigation equipment V2 is installed on the middle frame of the secondary lining trolley 10; The secondary irrigation equipment V2 is equipped with a secondary irrigation pump 112 and a tertiary irrigation pump 113; The secondary injection pump 112 and the tertiary injection pump 113 are connected to the auxiliary injection pipe of the independent auxiliary injection window 402; The secondary injection pump 112 is connected to a lower-level auxiliary injection pipe; The working pressure P2 of the secondary injection pump is greater than the working pressure P3 of the tertiary injection pump, but less than the pressure of the primary pressure detector P1.
[0008] Furthermore, the concrete outlet assembly 2000 includes: The main concrete outlet pipe 210 has its first end connected to the interface of the arch working window 403, and its second end extends towards the horizontal bottom surface. Multiple buffer chambers 211 are equally spaced on the main concrete outlet pipe 210, and an exhaust pipe and an automatic shut-off valve are installed on the buffer chamber 211. A control valve Kx is provided between adjacent buffer chambers 211.
[0009] Furthermore, the volume of the buffer chamber 211 located at the distance from the working window 403 of the arch is larger than the volume of other buffer chambers, and it is positioned as buffer chamber V4. The buffer chamber V4 is connected to the concrete inlet of the secondary pouring equipment V2 through the return pipe 220.
[0010] Furthermore, the marking group is positioned using a five-point positioning method: A center point is set at the center of the top mold of the secondary lining trolley 10; Two sets of symmetrical hinge points are provided at the arc-shaped position of the side mold of the secondary lining trolley 10; Two sets of bottom feet are provided at the lowest point of the side mold of the secondary lining trolley 10; The centerline of the secondary lining trolley 10 is determined by using a plumb line to mark the center point of the initial support of the pouring section.
[0011] Furthermore, a compaction sensor is installed on the arch to detect that the concrete has sufficient fluidity at the arch.
[0012] Furthermore, the concrete of the side walls and arch foot is vibrated using a trolley-operated window immersion vibrator, and the vibration time does not exceed 30 seconds. The arch is constructed using multiple vibrators, each of which is started independently, and the vibration time of the vibrators at different locations does not exceed 50 seconds. The vibration test standard is: the concrete does not settle, has no air bubbles, and the surface shows a layer of slurry.
[0013] Furthermore, the interval between pouring of two adjacent layers shall not exceed 2 hours.
[0014] The present invention has the following beneficial effects: Firstly, compared to the traditional trolley casting method, this technical solution can achieve less leakage, thereby preventing excessive void rate in the arch. The layered casting system allows for more flexible material placement, the working window can be closed within the normal technical requirements time, and the position difference on both sides of the grouting cavity is easier to control, which can significantly improve construction efficiency, reduce the void rate in the arch to below 2%, and reduce the structural leakage rate by 80%. Secondly, this technical solution significantly reduces voids in the secondary lining pouring, ensuring that the area of honeycomb, pitting, and air bubbles per linear meter does not exceed 0.3%, resulting in straight and aesthetically pleasing structural outlines and uniform concrete color.
[0015] Thirdly, this scheme can achieve continuous pouring, has strong ability to control the position difference on both sides of synchronous pouring, can close the working window within the specified design time, and reduce the time and frequency of auxiliary vibration guidance, which greatly improves the continuity of secondary lining pouring construction. Attached Figure Description
[0016] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0017] Figure 1 This is a schematic diagram of the configuration of the secondary lining trolley, panel, and track of the present invention; Figure 2 This is a schematic diagram illustrating the implementation of the layered casting system of the present invention; Figure 3 A schematic diagram showing the configuration of the working bed of the present invention; Figure 4 This is a schematic diagram of the overall embodiment of the present invention.
[0018] The reference numerals in the figure are: 10 secondary lining trolleys, 20 pouring section support layer, 100 panel, and 30 track; 40 screw jacks, 50 formwork, 1000 layered pouring system; 501 for pouring formwork cavity; 2000 for concrete outlet assembly; Low-position interface 101, main concrete injection pipe 102; Main concrete pouring equipment V1, primary grouting pump 110, primary pressure detector P1; Working window 401, auxiliary injection window 402; Secondary irrigation equipment V2, secondary irrigation pump 112, tertiary irrigation pump 113; The working pressure of the secondary injection pump is P2, and the working pressure of the tertiary injection pump is P3. Main concrete outlet pipe 210, arch working window 403, buffer chamber 211, control valve Kx; Buffer chamber V4, reflux pipe 220. Detailed Implementation
[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. It should be noted that, for ease of description, in this application, "left side" is referred to as "first end", "right side" as "second end", "upper side" as "first end", and "lower side" as "second end" in the current view. The purpose of such description is to clearly express the technical solution and should not be construed as an improper limitation of the technical solution of this application.
[0020] This invention aims to address the technical problem in existing secondary lining pouring construction processes that lack sufficient control over construction continuity, easily leading to construction hazards and potential failures. It provides a construction method for layered pouring of tunnel secondary lining using a trolley, which can be referenced in the appendix. Figure 1-4 As shown, it includes the following steps: Step S1: Confirmation and inspection of secondary lining construction conditions. Before the secondary lining trolley 10 is in place, check whether there are hollow areas in the support layer 20 of the pouring section. If there are hollow areas, repair or restoration work is required. A tunnel laser scanner was used to detect whether the tunnel cross section encroached on the secondary lining limit line, and the installation of the tunnel chamber embedded parts was completed to confirm that the conditions for secondary lining construction were met. Step S2: Check the curvature and flatness of the panel 100 of the secondary lining trolley 10, and complete the grinding, degreasing and rust prevention of the panel 100, as well as the tunnel measurement control points, and determine the center points of the front and rear ends of the secondary lining pouring section. The track 30 for installing the secondary lining trolley 10 is precisely positioned and matched to the track 30 by setting a group of markers on the secondary lining pouring section. Step S3: After the secondary lining trolley 10 is moved into place, the secondary lining trolley 10 is fixed by the secondary lining trolley braking device, and multiple screw jacks 40 are used to tightly attach the panel 100 to the formwork 50 and the concrete surface of the pouring section support layer 20. The panel 100 should have an overlap or butt joint with the concrete of the previous construction module of at least 10cm to ensure the continuous control of the construction module. Step S4, the concrete pouring process, uses a layered pouring system 1000 to pour concrete using multiple delivery pumps, so that the height difference between the left and right sides of the pouring template cavity 501 is less than 50cm. That is, different pressures are used for layered pouring to compensate for the unevenness caused by the continuous increase of the main concrete injection pipe 102 during pouring, so that the working window 401 can be kept closed according to the regulations. The vertical distance between the concrete outlet and the pouring surface is controlled within 1.2m using the concrete outlet component 2000 to prevent concrete segregation. Step S5: During the concrete pouring process, whenever an additional set of the conveying pumps is started, pressure is applied to one side of the multiple 40 threaded jacks to counteract the deformation of the formwork. The layered multi-stage pouring system is connected to the main concrete injection pipe 102 at the low-level interface 101; Firstly, compared to the traditional trolley casting method, this technical solution can achieve less leakage, thereby preventing excessive void rate in the arch. The layered casting system allows for more flexible material placement, the working window can be closed within the normal technical requirements time, and the position difference on both sides of the grouting cavity is easier to control, which can significantly improve construction efficiency, reduce the void rate in the arch to below 2%, and reduce the structural leakage rate by 80%. Secondly, this technical solution significantly reduces voids in the secondary lining pouring, ensuring that the area of honeycomb, pitting, and air bubbles per linear meter does not exceed 0.3%, resulting in straight and aesthetically pleasing structural outlines and uniform concrete color.
[0021] Thirdly, this scheme can achieve continuous pouring, has strong ability to control the position difference on both sides of synchronous pouring, can close the working window within the specified design time, and reduce the time and frequency of auxiliary vibration guidance, which greatly improves the continuity of secondary lining pouring construction.
[0022] In one specific embodiment, please refer to Figure 1-4 As shown, the layered casting system 1000 includes: The main concrete pouring equipment V1 is connected to the main concrete injection pipe 102 via two sets of primary injection pumps 110. A primary pressure detector P1 is installed on the main concrete injection pipe 102.
[0023] Further, please refer to Figure 3 As shown, the panel 100 has windows arranged from bottom to top. The windows include: a working window 401 for observing the grouting and closing it based on the grouting process and construction progress; and an auxiliary grouting window 402 for setting up a secondary grouting pipe. The panel 100 has multiple virtual planning levels arranged from bottom to top. The working window 401 and the auxiliary grouting window 402 of each virtual planning level are arranged alternately.
[0024] In one specific embodiment, please refer to Figure 1-4 As shown, it also includes: a secondary irrigation device V2, which is installed on the middle frame of the secondary lining trolley 10; The secondary irrigation equipment V2 is equipped with a secondary irrigation pump 112 and a tertiary irrigation pump 113; The secondary injection pump 112 and the tertiary injection pump 113 are connected to the auxiliary injection pipe of the independent auxiliary injection window 402; The secondary injection pump 112 is connected to a lower-level auxiliary injection pipe; The working pressure P2 of the secondary injection pump is greater than the working pressure P3 of the tertiary injection pump, but less than the pressure of the primary pressure detector P1; The usage method of the above-mentioned layered casting system 1000 is as follows: First, the work window 401 and auxiliary injection window 402 of each virtual planning level are arranged alternately, that is, the panel 100 includes two types of windows, as shown in the attached figure. Figure 3 As shown, the working window 401 is a standard window used to observe the concrete pouring surface and to arrange vibration. As the pouring pressure of the main concrete injection pipe 102 increases, the concrete slurry poured on both sides of the pouring formwork cavity 501 rises continuously. When it approaches the working window 401, this is referred to as stratification in existing technology. At this point, conventional pouring needs to be paused for less than 2 hours, while simultaneously coordinating with vibration. Once closed, this position can no longer be observed. As the concrete slurry continues to rise, it reaches the next height at the working window 401, and this process repeats to complete the stratified pouring. The types of malfunctions and potential hazards are as follows: The self-weight of the pouring formwork cavity 501 continuously requires the primary pouring pump 110 to increase its pressure head. However, during the above process, uneven vibration and control of the position difference of the pouring formwork cavity 501 can lead to a mismatch in the output power of the two sets of primary pouring pumps 110, resulting in momentary or short-term excessive pressure. If the adjustment is not timely, this can cause the concrete slurry in the pouring formwork cavity 501 to generate air bubbles and exhibit uneven flow, thereby affecting the vibration frequency and delaying the closing time of the working window 401. In this solution, an auxiliary pouring window 402 is used, which serves as both a regular working window and a connection window. When concrete grout is injected, the secondary grouting pump 112 and the tertiary grouting pump 113 are connected to the auxiliary grouting pipe of the independent auxiliary grouting window 402. This means that independent auxiliary grouting is carried out at the layer position. Since it can be confirmed that concrete grout has arrived at the working window 401 of this layer, the auxiliary grouting pipe of the auxiliary grouting window 402 is opened. The grouting of the secondary grouting equipment V2 with the secondary grouting pump 112 and the tertiary grouting pump 113 has the least impact on the grouting template cavity 501 that has been grouted. It can also make up for the unevenness of the position difference on both sides of the grouting template cavity 501. It should be noted that: This solution is configured with a secondary injection pump 112 and a tertiary injection pump 113. Too many pumps would generate additional pipe laying requirements and power equipment configuration requirements. Configuring a secondary injection pump 112 and a tertiary injection pump 113 is the optimal embodiment. Of particular importance is that configuring a secondary injection pump 112 and a tertiary injection pump 113 can effectively reduce the output power and pressure of the primary injection pump 110. Specific technical requirements must be met: The working pressure P2 of the secondary grouting pump is greater than the working pressure P3 of the tertiary grouting pump, but less than the pressure of the primary pressure detector P1. This minimizes the influence between grouting pressures during the layered and graded injection of concrete slurry. It not only effectively increases the grouting flow rate but also reduces the pressure increase caused by the frequency conversion control of the primary grouting pump 110. The positional difference of the concrete slurry on both sides of the grouting template cavity 501 is also easier to control, and the actual vibration frequency can be reduced. This saves time in closing the working window 401 and ensures the sealing quality.
[0025] The concrete outlet component 2000 is used to control the vertical distance between the concrete outlet and the pouring surface to within 1.2m (in fact, the concrete slurry injection process can be broken down into concrete slurry injection and air removal from the pouring formwork cavity 501; controlling the distance to within 1.2m can be further broken down as follows: injection at a low point requires coordination with air removal at a low point, and injection at a high point requires coordination with air removal at a high point). Therefore, in a specific embodiment, please refer to... Figure 2 , 4 As shown: The concrete outlet assembly 2000 includes: a main concrete outlet pipe 210, the first end of which is connected to the interface of the arch working window 403, and the second end of which extends towards the horizontal bottom surface; a plurality of buffer chambers 211 are equally spaced on the main concrete outlet pipe 210, and an exhaust pipe and an automatic shut-off valve are provided on the buffer chambers 211. A control valve Kx is provided between adjacent buffer chambers 211; After the main concrete injection pipe 102 is filled with concrete slurry, in addition to the working window 401 balancing the gas pressure, the automatic shut-off valve at the low position of the main concrete outlet pipe 210 is opened, and the low-position exhaust pipe is activated to control the vertical distance. Gradually, by switching the control valve Kx and the automatic shut-off valve, the exhaust pipes at each position of the main concrete outlet pipe 210 are activated in stages to further improve the synchronous pouring position difference control capability.
[0026] In one specific embodiment, please refer to Figure 2 As shown, when grouting at the arch, a buffer chamber V4 is used. The volume of the buffer chamber 211, which is located at the arch working window 403, is larger than the volume of other buffer chambers and is positioned as buffer chamber V4. The buffer chamber V4 is connected to the concrete inlet of the secondary grouting equipment V2 through the return pipe 220. The concrete slurry introduced into the secondary grouting equipment V2 can be used for pre-grouting of the secondary grouting pump 112 and the tertiary grouting pump 113 and their pipelines. The main concrete outlet pipe 210 is connected to the arch working window 403 by a detachable flange. An independent control butterfly valve can be installed on the connecting pipe of the arch working window 403 for quick shut-off.
[0027] In one specific embodiment, the marking group is positioned using a five-point positioning method: A center point is set at the center of the top mold of the secondary lining trolley 10; Two sets of symmetrical hinge points are provided at the arc-shaped position of the side mold of the secondary lining trolley 10; Two sets of bottom feet are provided at the lowest point of the side mold of the secondary lining trolley 10; The centerline of the secondary lining trolley 10 is determined by using a plumb line to mark the center point of the initial support of the pouring section.
[0028] In one specific embodiment, a compaction sensor is installed on the arch to detect that the concrete has sufficient fluidity at the arch, serving as an effective means of monitoring voids.
[0029] In one specific embodiment, the concrete of the side walls and arch foot is vibrated using a trolley-operated window immersion vibrator, and the vibration time does not exceed 30 seconds. The arch is constructed using multiple vibrators, each of which is started independently, and the vibration time of the vibrators at different locations does not exceed 50 seconds. The vibration test standard is: the concrete does not settle, has no air bubbles, and the surface shows a layer of slurry.
[0030] In one specific embodiment, the interval between pouring of two adjacent layers does not exceed 2 hours.
[0031] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A construction method for layered pouring of a tunnel secondary lining trolley, characterized in that, The application relates to a two-lining trolley and a two-lining pouring method thereof. Step S1, checking whether the supporting layer (20) of the pouring section exists before the two-lining trolley (10) is positioned; A tunnel laser scanner is used to detect whether the tunnel section invades the two-lining limit line, to complete the installation of the tunnel chamber embedded part, and to confirm that the two-lining construction conditions are met; Step S2, checking the curvature and flatness of the panel (100) of the two-lining trolley (10), and completing the polishing and rust prevention of the panel (100), and determining the center points of the front and rear ends of the two-lining pouring section through tunnel measurement control points; The track (30) of the two-lining trolley (10) is installed, the two-lining trolley (10) is accurately positioned through the setting of a mark group on the two-lining pouring section, and the track (30) is matched; Step S3, after the two-lining trolley (10) is positioned through walking, the two-lining trolley (10) is fixed through a two-lining trolley braking device, and the panel (100) is tightly attached to the concrete surface of the supporting layer (20) and the formwork (50) through a plurality of screw jacks (40); The panel (100) should be overlapped or butted with the concrete of the previous construction module by more than or equal to 10 cm; Step S4, in the concrete pouring process, a layered pouring system (1000) is used to fill through a plurality of delivery pumps, so that the left and right height difference of the filling formwork cavity (501) is less than 50 cm; The vertical distance between the concrete outlet and the pouring surface is controlled to be within 1.2 m through a concrete outlet assembly (2000), so as to prevent concrete segregation; Step S5, in the concrete pouring process, when a group of delivery pumps is started, one-side pressure adjustment of the plurality of screw jacks (40) is performed to offset the formwork deformation. The layered multi-stage pouring system is connected with a main concrete injection pipe (102) through a low-position interface (101).
2. The method of claim 1, wherein the second lining trolley is constructed by the steps of: The layered pouring system (1000) comprises: A main concrete filling device (V1) is connected with the main concrete injection pipe (102) through two groups of first-stage filling pumps (110), and a first-stage pressure detector (P1) is arranged on the main concrete injection pipe (102).
3. The method of claim 2, wherein the second lining trolley is constructed by the steps of: The panel (100) is provided with windows from bottom to top, and the windows comprise: A working window (401) is used for observing filling and is closed based on the filling process and construction progress; An auxiliary filling window (402) is provided with a vice filling connecting pipe; The panel (100) is provided with a plurality of virtual planning levels from bottom to top; The working window (401) and the auxiliary filling window (402) of each virtual planning level are alternately arranged.
4. The method of claim 3, wherein the second lining trolley is constructed by the steps of: The layered pouring system (1000) further comprises: A second-stage filling device (V2) is arranged on the middle frame of the two-lining trolley (10); The second-stage filling device (V2) is configured with a second-stage filling pump (112) and a third-stage filling pump (113); The second-stage filling pump (112) and the third-stage filling pump (113) are connected with the vice filling connecting pipe of the independent auxiliary filling window (402); The second-stage filling pump (112) is connected with the low-position vice filling connecting pipe; The working pressure (P2) of the second-stage filling pump is greater than the working pressure (P3) of the third-stage filling pump and is less than the pressure of the first-stage pressure detector (P1).
5. The construction method for layered pouring of tunnel secondary lining using a trolley as described in claim 4, characterized in that, The concrete outlet assembly (2000) comprises: a main concrete outlet pipe (210) with a first end connected to the interface of the working dome window (403) and a second end extending towards the horizontal bottom surface; a plurality of buffer cavities (211) are arranged on the main concrete outlet pipe (210) at equal intervals, and an exhaust pipe and an automatic shut-off valve are arranged on the buffer cavities (211); a control valve (Kx) is arranged between adjacent buffer cavities (211).
6. The method of claim 5, wherein the second lining trolley is constructed by the steps of: The volume of the buffer cavity (211) adjacent to the working dome window (403) is larger than that of other buffer cavities, and is positioned as a buffer chamber (V4), which is connected to the concrete inlet of the secondary pouring device (V2) through a backflow pipe (220).
7. The method of claim 1, wherein the method further comprises: after the second lining is formed, forming a third lining on the second lining using a third lining trolley. 5 The marking group is in the form of a five-point positioning method: a center point is arranged at the center of the top die of the secondary lining trolley (10); two sets of symmetrical hinge points are arranged at the arc-shaped position of the side die of the secondary lining trolley (10); two sets of bottom foot points are arranged at the low point of the side die of the secondary lining trolley (10); the center line of the secondary lining trolley (10) is determined by using lofting plumb line at the center point of the initial support of the pouring section.
8. The construction method for layered pouring of tunnel secondary lining using a trolley as described in claim 7, characterized in that, A compaction sensor is arranged on the dome to detect whether the concrete has sufficient fluidity on the dome.
9. The construction method for layered pouring of tunnel secondary lining using a trolley as described in claim 8, characterized in that, The concrete in the side wall and the arch foot is vibrated by using the trolley operation window plug-in vibrator, and the vibrating time is not more than 30s; the dome uses a plurality of vibrators, each vibrator is started independently, and the vibration of different position vibrators is not more than 50s; the vibration inspection standard is that the concrete does not sink, has no air bubbles, and the surface presents floating slurry.
10. The construction method for layered pouring of tunnel secondary lining using a trolley as described in claim 9, characterized in that, The interval time of pouring between adjacent two layers is not more than 2 hours.