Cut and cover semi topdown construction method for underground excavation of intersecting transferable subway station

Abstract

To provide a cut and cover semi topdown construction method for an underground excavation of an intersecting transferable subway station.SOLUTION: A section of a station node is a section of an arch top straight wall of a third basement, a first basement is a station layer 1, a second basement is a platform layer 2 of a subway rail track A, and the third basement is a platform layer 3 of a subway rail track B, wherein directions of the subway rail track A and the subway track B are orthogonal to each other. The method comprises: at first, constructing secondary liner structures of the first basement and the second basement; and carrying out a topdown construction method for the third basement structure after a shield machine progresses and passes a station as excavating, which is advantageous to improve whole construction efficiency, secures timely completion of a tunnel for two layer tracks, realizes timely a rail completion and power supply for overhead lines, makes the whole line completed as soon as possible, effectively reduces risks caused by a high side wall, improves construction efficiency hugely, reduces a whole construction period, and mitigates construction risks.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the technical field of underground construction, in particular to the underground excavation of an interchange-type subway station. This article relates to the semi-reverse construction method for bed and cover. [Background technology]

[0002] At present, the construction of urban rail transport networks has become the focus of transport construction in many large cities. The basic feature of the networked urban rail transport construction is the intersection of the track network. The problem is that more and more transfer nodes are formed at these points. The nodes will house transfer hubs, allowing passengers to quickly transfer from one track to another. Transferring at a node is one of the most common transfer methods. Generally speaking, this refers to a transfer method where two tracks cross, as opposed to a parallel transfer. At the intersection of the two tracks, the structure of the overlapping tunnels of the two tracks is integrated. Generally, the cross section of a transfer node is a large cross section on the third basement floor. The first basement floor is the station building, and the second and third basement floors are the platforms for both lines. The construction of stations is generally prone to affect the construction period of section mechanical construction methods, especially for transfer stations. The most serious situation is in the area of ​​the railway line, where the construction period for both lines must be taken into account. The shield machine for the tracks on the second basement platform has arrived, and the transfer node is It is necessary to create conditions that allow the shield machine to dig through the mezzanine as quickly as possible. In this case, in the conventional construction method, the shield machine digs through the tunnel and passes through the station. Before this can be done, the entire section must be excavated and the secondary lining structure of the station must be completed from bottom to top ( At least the mezzanine floor must be completed and reach the design strength. In this case, the cross section of the third floor Not only is there a risk of excavating the side walls of the station, but the construction period for the station will be extended and the station access for the shield machine will be reduced. This could result in delays in operation, which could affect operations at nodes in the section.

[0003] For this reason, the designer of the present invention has taken into consideration the above-mentioned shortcomings, and has conducted thorough research and design, Combining our many years of experience and track record, we have developed a cutting and digging system for underground interchange subway stations. We researched and designed a cover semi-reverse construction method to overcome the above-mentioned shortcomings. Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to solve the deficiencies of the prior art, improve the efficiency of the entire construction, and shorten the overall construction period. This can reduce construction risks and cut underground excavation for interchange subway stations. To provide an and cover semi-reverse construction method. [Means for solving the problem]

[0005] In order to achieve the above object, the present invention provides The cross section of the station node of the cross-transfer subway is three stories underground, the first underground floor is the station building layer, and the The lower two floors are the platform level for subway line A, the third basement floor is the platform level for subway line B, and the front The track directions of the subway line A and subway line B are perpendicular to each other, and the station building level and the platform level of subway line A are The arch cover method is used for construction of the shield tunnel for section A of the subway line. After Shin had dug through the station, the tunnel was dug under the arch cover by reverse construction. Underground cross-transfer subway station with cut-and-cover construction of platform level for subway track B A drilling-cut and cover semi-inverted construction method, The pilot tunnel on the left side of the arch will be excavated in stages. After excavation is completed, a 40 mm thick concrete tunnel will be installed. The initial spraying of cleat was carried out to seal the surrounding rock, anchor rods were installed, and the lattice art was The temporary steel arch frame of the pilot tunnel on the left side of the arch was placed. Step 1 is to erect the structure and then spray concrete to a thickness of 350 mm. The pilot tunnel on the right side of the arch was excavated in stages, and immediately after excavation was completed, a 40 mm thick core was The initial spraying of concrete was carried out to seal the surrounding rocks, anchor rods were installed, and the lattice structure was A temporary steel arch frame was then installed, and 350 cm of concrete was poured into the arch. Step 2 is to spray up to a thickness of mm, Excavate the remaining surrounding rock of the central pilot tunnel of the arch of the station and Step 3 is to install and fix the temporary steel arch frame of the tunnel; The bottom base layer is constructed, and once it has reached the desired strength, the arch leg joists on both sides are constructed. Step 4: Part of the temporary steel arch frame was removed to create a space effect, and a waterproof layer was laid, and the arch cover was installed. Step 5: constructing a secondary lining structure by pre-clearing the side wall construction joints; When the secondary lining structure using the arch cover reaches the designed strength, a gradient is created and the intermediate layer of core soil is Step 6 is to excavate the soil; The surrounding rocks on both sides of the station's middle layer are excavated layer by layer from top to bottom, and excavation is performed step by step to reach the relevant layer. The anchor rod is lowered 0.5m, and the anchor rods on both sides are installed and concrete is poured. Once the drilling is complete, step 7 is drilling again. When excavation was performed to the design elevation, mortar and tunnel slag were piled up to the bottom elevation of the mezzanine on the second basement floor. When the foundation load required for the shield machine to excavate is met, the mezzanine structure and Step 8: Construct the secondary lining structure for the side walls of the first and second basement floors using the pour-in method from bottom to top. and, When the secondary lining structure of the mezzanine level on the second basement floor reaches the designed strength, the roadbed will be backfilled and the rails will be laid. Step 9: The shield machine for constructing subway line A digs through the station. and, The left section tunnel of subway line B is used as a construction channel to circulate the platform level of subway line B. The drilling was carried out efficiently, temporary steel supports were installed in a timely manner, and the support was The secondary lining structure for the third basement floor will be constructed in a timely manner, and the secondary Step 10: After the construction of the lining structure is completed, proceed to the next excavation cycle; After the secondary lining structure on the third basement floor is completed, the remaining interface of subway line B will be excavated. After the shield machine for construction of subway line B has passed through the station, the internal structure is constructed. Step 11: Construction of underground excavation of interchange metro stations, including cut and cover -Provides a semi-reverse construction method.

[0006] In step 1, at least one arch leg position in the left pilot tunnel of the arch section In step 2, the pilot tunnel access on the right side of the arch is installed. Install at least one locking bolt at the base leg location.

[0007] In the above steps 1 and 2, each pilot tunnel is excavated. The tunnel is 15m or longer in feet.

[0008] In step 4, the inner ends of the lock bolts 14 installed in steps 1 and 2 are Cast inside the arch leg joist to ensure the stability and reliability of the arch leg joist . In the step 5, primary molding is used to construct the secondary lining structure 17 by the arch cover. An "L" shaped joint is provided at each joint of the side wall construction joint.

[0009] In step 6, the slope of the excavation is less than 1:0.5, and both sides The horizontal distance from the ridge to the shoulder is 3m or more.

[0010] In step 8, mortar and tunnel slag are backfilled and compacted uniformly until the compaction density is ≥ When compacting at 93%, the thickness of each layer should be 25~30cm, and the side walls of the first and second basement floors should be The sub-lining structure and permanent concrete columns are cast at least 500 mm below the mezzanine level on the second basement floor. The ratio of pre-retained joints of reinforcing bars within the same cross section shall be 50% or less.

[0011] Step 10 has the following sub-steps: The left section tunnel of subway line B was used as the construction channel, and the left section of the third basement floor was constructed using the bench construction method. The rail area is excavated in cycle feet, and the excavation is completed when cycle feet is reached. Each time a construction project is completed, the shotcrete-rock bolt supports must be carried out in a timely manner to ensure the construction of temporary steel structures. Step 10.1 is to erect the support to support the top plate of the third basement floor. Dig from the center to excavate the pilot tunnel in the center of the third basement level, and then similarly Excavation is performed using the cycle method, and only cycle feet are excavated, and excavation for the cycle feet is completed. Each time, the shotcrete-rock bolt supports were carried out in a timely manner, and the temporary steel Supports will be erected to support the top plate of the 3rd basement floor, and the left track rail area of ​​the 3rd basement floor will be Step 10.2, which begins the construction of the secondary lining structure of the third basement floor of the area in stages; Open the tunnel from both sides and fill the area of ​​the right-side rail area on the third basement floor in cycle feet. Excavation and cycle each foot of excavation completed with shotcrete-rockbolt The construction of the shoring was carried out in a timely manner, and temporary steel supports were erected to support the top plate of the third basement floor. By doing so, the secondary lining structure of the left track area on the third basement floor will be completed, and the underground Step 10: Adjust the temporary support in the left rail area on the third floor to within the secondary lining structure. .3 and Next, the secondary lining structure for the central pilot tunnel and the right-side rail area on the third basement floor After the secondary lining structure on the third basement floor was constructed and sealed, temporary steel supports were installed. Step 10.4 of adjusting the secondary lining structure range; The remaining rock mass in the center was excavated, and similarly, bench excavation was performed, and only cycle feet were excavated. Cut and cycle each foot of excavation completed with shotcrete-rock bolts Implement shoring in a timely manner and erect temporary steel supports to support the top plate of the third basement floor. Step 10.5 and Step 10: Completing the remainder of the secondary lining structure on the third basement floor and installing temporary steel supports .6 and Excavate the right-side section tunnel of subway line B and install three grid steel frames in parallel. Immediately after excavation, C25 concrete was sprayed to seal the surrounding rock and a lattice arch frame was installed. The tower and temporary steel supports are erected, the reinforcing steel mesh is tied in, and concrete is sprayed. Step 10.7 includes:

[0012] Steps 10.1, 10.2, 10.3 and 10.5 are performed in soil layers and unstable rock bodies. The cycle feet are 0.5 to 1.2 meters, and within the stable rocks the cycle feet are 1 to 2 meters. 1.5 meters, and the stabilization time for the excavation surface of the unstable rock mass does not meet the initial support construction. In such cases, reinforcement measures will be taken by pre-support or grout injection. Effect of the Invention

[0013] As can be seen from the above, the underground excavation-cut-and-uncut of the cross-transfer type subway station of the present invention The docover semi-reverse construction method has the following effects. 1. First, the secondary lining structure for the first and second basement floors is constructed, and the shield machine digs in. The method of constructing the three-story underground structure in reverse after passing through the station is advantageous in improving the overall construction efficiency. This will ensure timely completion of the tunnels on the two levels of track, and timely completion of the rails and energization of the overhead lines. We will do our best to complete the entire line as quickly as possible and complete the rail and power the overhead lines in a timely manner. And we will reopen the entire line as soon as possible. 2. Compared to the conventional method of constructing the structure by pouring in order after the entire section has been excavated, This can shorten the construction period by at least three months. 3. This method is also more efficient than the double-sided drift method of excavating the section of the third floor, which is due to the high side walls. This method reduces the risk caused by the above-mentioned factors, and therefore ensures safety while This is a method to maximize construction efficiency, shorten the overall construction period, and reduce construction risks. The details of the present invention can be understood from the following description and the accompanying drawings. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 shows a schematic cross-sectional structure of a transfer node of the present invention. [Diagram 2] FIG. 2 is a schematic plan view of the third basement floor of the transfer node of the present invention. [Diagram 3] FIG. 3A shows a schematic diagram of the construction sequence of the cross section of a transfer node in the underground excavation-cut-and-cover semi-inverted construction method of an inter-transfer subway station of the present invention. [Figure 4] FIG. 3B shows a schematic diagram of the construction sequence of the cross section of a transfer node in the underground excavation-cut-and-cover semi-inverted construction method of an inter-transfer subway station of the present invention. [Diagram 5] FIG. 3C shows a schematic diagram of the construction sequence of the cross section of a transfer node in the underground excavation-cut-and-cover semi-inverted construction method of an inter-transfer subway station of the present invention. [Figure 6] FIG. 3D shows a schematic diagram of the construction sequence of the cross section of a transfer node in the underground excavation-cut-and-cover semi-inverted construction method of an inter-transfer subway station of the present invention. [Figure 7] FIG. 3E shows a schematic diagram of the construction sequence of the cross section of a transfer node in the underground excavation-cut-and-cover semi-inverted construction method of an inter-transfer subway station of the present invention. [Figure 8] FIG. 3F shows a schematic diagram of the construction sequence of the cross section of a transfer node in the underground excavation-cut-and-cover semi-inverted construction method of an inter-transfer subway station of the present invention. [Figure 9] FIG. 3G shows a schematic diagram of the construction sequence of the cross section of a transfer node in the underground excavation-cut-and-cover semi-inverted construction method of an inter-transfer subway station of the present invention. [Figure 10] FIG. 3H shows a schematic diagram of the construction sequence of the cross section of a transfer node in the underground excavation-cut-and-cover semi-inverted construction method of an inter-transfer subway station of the present invention. [Figure 11] FIG. 4A shows a schematic diagram of the construction sequence of the third basement floor plan in the underground excavation-cut-and-cover semi-inverted construction method of an interchange-type subway station of the present invention. [Figure 12] FIG. 4B is a schematic diagram showing the construction sequence of the third basement floor plan in the underground excavation-cut-and-cover semi-inverted construction method of an interchange-type subway station of the present invention. [Figure 13]FIG. 4C shows a schematic diagram of the construction sequence for the third basement floor plan using the underground excavation-cut-and-cover semi-inverted construction method of an interchange-type subway station of the present invention. [Figure 14] FIG. 4D shows a schematic diagram of the construction sequence of the third basement floor plan in the underground excavation-cut-and-cover semi-inverted construction method of an interchange-type subway station of the present invention. [Figure 15] FIG. 4E shows a schematic diagram of the construction sequence for the third basement floor plan using the underground excavation-cut-and-cover semi-inverted construction method of an interchange-type subway station of the present invention. [Figure 16] FIG. 4F shows a schematic diagram of the construction sequence for the third basement floor plan using the underground excavation-cut-and-cover semi-inverted construction method of the present invention for an interchange-type subway station. [Figure 17] FIG. 4G shows a schematic diagram of the construction sequence for the third basement floor plan in the underground excavation-cut-and-cover semi-inverted construction method of an inter-transit subway station of the present invention. [Figure 18] FIG. 4H shows a schematic diagram of the construction sequence for the third basement floor plan using the underground excavation-cut-and-cover semi-inverted construction method of an interchange-type subway station of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] 1 and 2 show an underground excavation cut and cover section of an interchange subway station according to the present invention. The shape of a station node of an intersection transfer type subway in the reverse construction method is shown, and the station The cross section of the node is the cross section of the arch top straight wall on the 3rd basement floor, and the 1st basement floor is the station building floor 1. The second basement floor is platform level 2 for subway line A, and the third basement floor is platform level 3 for subway line B. The track directions of the subway line A and the subway line B are perpendicular to each other, and the transfer node is The transfer node may be a shaped transfer node, a T-shaped transfer node, or an L-shaped transfer node. There is no limitation, and the transfer node may be of any form as described in the present invention.

[0016] In the underground excavation - cut and cover semi-reverse construction method for the above-mentioned cross-transfer subway station, The station building layer 1 and platform layer 2 of subway track A are constructed using the arch cover method. After the shield machine for construction of section A of the subway line had dug through the station, it was driven by the reverse construction method. The cut and cover construction of the platform layer of subway track B was carried out under the cross section by the arch cover method. Step 3 is performed. Specifically, the present invention may include the following steps:

[0017] Step 1: As shown in FIG. 3A, the pilot tunnel 11 on the left side of the arch is opened step by step. Excavation was carried out, and immediately after completion of excavation, an initial spraying of 40mm thick concrete was carried out to seal the surrounding rock. Then, the top anchor rod 7 of the pilot tunnel 11 on the left side of the arch section is installed, and the The child arch frame was placed, and the temporary steel arch of pilot tunnel 11 was placed on the left side of the arch. The frame 15 is erected, the reinforcing steel mesh is tied in, and concrete is poured in until it is 350mm thick. To ensure the stability of the initial support, the pilot tunnel on the left side of the arch was At least one locking bolt 14 may be attached at the eleven arch leg locations.

[0018] Step 2: As shown in FIG. 3B, the pilot tunnel 12 on the right side of the arch is opened step by step. Excavation was carried out, and immediately after completion of excavation, an initial spraying of 40mm thick concrete was carried out to seal the surrounding rock. Then, the anchor rod 7 of the pilot tunnel 12 on the right side of the arch section is installed, and the lattice arch The temporary steel arch frame of the pilot tunnel 12 on the right side of the arch was placed. The 15-m long tube was erected, the reinforcing steel mesh was tied, and concrete was sprayed to a thickness of 350 mm. In order to ensure the stability of the initial support, the arch of the pilot tunnel 12 on the right side of the arch At least one locking bolt 14 may be attached to the arch leg location.

[0019] In the above steps 1 and 2, when the pilot tunnel is excavated, the explosion In order to have a certain impact on the pilot tunnels being constructed, the fill factor of each pilot tunnel under construction will be The length of the concrete pipe must be at least 15m. The application must be carried out in strict accordance with the process requirements. It must be clear and free of cracks, spalling, leaks, exposed rebar, cavities, water leaks, etc. Concrete work should be carried out in sections, areas and layers from bottom up. There is.

[0020] Step 3: As shown in Figure 3C, the center of the station arch was cut while leaving a rock mass of more than 1m thick. Excavate the remaining surrounding rock of Pilot Tunnel 13 and excavate the central Pilot Tunnel 1 in the arch section. The temporary steel arch frame 15 is fixed to the central base. The explosion is controlled to protect the support of the beam.

[0021] Step 4: As shown in FIG. 3D, fabricate the bottom underlayer and wait until the bottom underlayer has the desired strength. Then, install the arch leg joists 16 on both sides, preferably in steps 1 and 2. The inner end of the attached rock bolt 14 is driven into the inside of the arch leg joist, and the arch leg Ensures stability and reliability of the joists.

[0022] Step 5: Remove part of the temporary steel arch frame 15 (remove it at once) by using the spatial effect. The length of the support to be removed is 6m or less), a waterproof layer is laid, and a secondary covering structure is provided using an arch cover. 17 to leave the side wall construction joints in advance. In addition, monitoring and measurement will be strengthened, and the segment Adjust the length of the message promptly.

[0023] The above step 5 specifically includes the following technical contents: 1. Primary molding is used to construct the secondary lining structure 17 using arch covers, and step-by-step injection is performed. I can't. 2. An "L"-shaped joint 18 is provided at each joint of the side wall construction joint, and the construction joint is filled The method used is to remove the concrete from the bottom 100 to 150 m from the construction joint. When poured into the concrete at 1000m, bleeding is eliminated and the concrete is filled with the same grade of shrinkage-free concrete. do.

[0024] Step 6: As shown in Figure 3E, the secondary lining structure 17 of the arch cover is designed to have the strength. Then, a gradient is created and the intermediate layer of core soil is excavated. The slope of the slope is 1:0.5 or less, and the horizontal distance from the slope to the top of the slope on both sides is It is over 3m.

[0025] Step 7: As shown in Figure 3F, the surrounding rocks on both sides of the station middle layer are excavated layer by layer from top to bottom, and the slab is When drilling to the relevant layer for each step, the anchor rod 7 is lowered 0.5 m and the anchors on both sides are Once the installation of the rod 7 and the spraying of concrete are completed, further excavation will commence.

[0026] Step 8: As shown in Figure 3G, when the excavation reaches the design elevation, the bottom of the mezzanine 23 on the second basement floor is Backfill the tunnel with mortar and tunnel slag 31 up to the altitude, and use the basic materials required for the shield machine to excavate. When the foundation load capacity is met, the secondary lining structure of the mezzanine structure 23 and the side walls of the first and second basement floors 24 will be constructed from bottom to top using the pour-in method.

[0027] In particular, step 8 specifically includes the following technical contents: 1. By uniformly compacting the backfilled mortar and tunnel slag 31, unevenness in the structure is eliminated. To avoid excessive load, backfill the tunnel slag by layer, and then apply a rolling density of 93% or more. When compacting, make each layer 25-30cm thick. Sand and mixed soil have good permeability and are suitable for soil. Poor quality soil cannot be used. 2. As the reverse construction method will be used for the 3rd basement floor, the secondary lining of the side walls of the 1st and 2nd basement floors will be Leave nodes on the structure 24 and the permanent concrete column 6, and install the secondary lining of the side walls on the first and second basement floors. The structure 24 and the permanent concrete column 6 are driven 500 mm or more below the mezzanine floor 23 on the second basement floor. The ratio of pre-reinforced joints of reinforcing bars in the same cross section shall be 50% or less, and pre-reinforced joints shall be needs to be securely protected.

[0028] Step 9: When the secondary lining structure of the mezzanine 23 on the second basement floor reaches the designed strength, backfill the roadbed. , the rails are laid, and at this time, the platform layer 2 of the subway track A is the left track section ton Tunnel 21 is connected to tunnel 22 on the right side of subway track A, and the shield machine is digging The conditions for passing through the station are met, and the shield machine for construction of subway line A digs through the station. It becomes possible to pass on what is needed.

[0029] Step 10: As shown in FIG. 3H and FIG. 3I, the left line section tunnel 33 of the subway line B is As a construction channel, the platform layer 3 of subway track B was excavated in a circular manner and temporary steel supports were installed. The supports are gradually removed for each excavation cycle, and the ground is The secondary lining structure 35 for the lower three floors will be constructed in a timely manner. Construction of the secondary lining structure 35 for the basement three floors After this is complete, the next drilling cycle begins.

[0030] In step 10, note the following: 1. During excavation, the upper mortar and tunnel slag 31 should be removed to avoid collapse. Attention should be paid to the stability of the mortar and tunnel slag 31. After removing the block 31 block by block to form a vibration-proof layer, blasting and excavation are carried out. 2. Explosion requires explosion design, and it is preferable to use smooth blasting. , It is necessary to timely modify the relevant parameters according to the explosion effect. Explosion parameters According to the principles of shallow hole, dense distribution, weak explosion, and gradual progress, the test explosion was carried out in the field. In the explosion design, the adjacent tunnels must be considered to ensure the safety of the construction. The main consideration is the effect of vibrations on the tunnel and adjacent buildings. 3. Tunnel excavation is carried out in order to reduce disturbance to the surrounding rock mass and to reduce the impact of vibrations on surrounding buildings. Therefore, the policy is "short feet, weak blasting, strong support, and quick sealing." It must be strictly followed. The vibration velocity of the explosion to the surrounding buildings must be within 15mm / s. If not, the surrounding buildings must be controlled to ensure their safety and stability. Mechanical excavation must be used to

[0031] Specifically, step 10 includes the following steps as sub-steps:

[0032] Step 10.1: As shown in Figure 4A, the left line section tunnel 33 of subway line B is constructed. As a channel, the third basement floor of the station was excavated using the bench construction method, and the left line rail area on the third basement floor was first excavated. Excavate the area 3A, and remove the mortar and tunnel slag 31 block by block before excavation. Then, explosive excavation is carried out to prevent the collapse of the mortar and tunnel slag. To ensure the safety of existing structures, excavate only cycle feet and avoid soil layers and unstable rocks. The depth should be 0.5 to 1.2 meters in stable rocks and 1 to 1.5 meters in unstable rocks. If the time required for stabilization of the cut surface does not meet the initial support construction requirements, reinforcement by pre-support or grout injection will be required. After each cycle of excavation, a shotcrete-rock The bolt supports were installed in a timely manner, and temporary steel supports 32 were erected to support the top plate of the third basement floor. Support the following.

[0033] Step 10.2: As shown in Figure 4B, the excavation of the left line rail area area 3A on the third basement floor is completed. After completion of this, dig from the central position and excavate pilot tunnel 3B in the center of the third basement floor. The tunnel is then excavated by the bench method, and mortar and tunnel slag 31 are poured into the tunnel before excavation. Rock by rock is removed to form a vibration-proof layer, then explosive excavation is carried out to deposit mortar and tunnel slabs. Prevents collapse of the lagoon and ensures the safety of existing structures. Only cycle feet are excavated and soil is removed. 0.5 to 1.2 meters in layers and unstable rock bodies, and 1 to 1.5 meters in stable rock bodies. If the stabilization time of the excavation surface of the unstable rock body does not meet the initial support construction, pre-support or gra Each time 1000 feet of excavation is completed, a reinforcement measure is taken by injecting sprayed concrete. Concrete-rock bolt support was carried out in a timely manner, and temporary steel supports 32 were erected. The top plate of the 3rd basement floor is supported by the left rail area 3A of the 3rd basement floor. The construction structure 35 is constructed in stages.

[0034] Step 10.3: As shown in Figures 4C and 4D, the central pilot tunnel on the third basement floor After the excavation of the 3B section is completed, the tunnel will be opened from both sides and the area of ​​the right-side rail area on the 3rd basement floor will be Area 3C is excavated, and similarly, mortar and tunnel slag 31 are poured into each block before excavation. The tunnel slag is then removed to form a vibration-proof layer, and then explosive excavation is carried out to prevent the collapse of the mortar and tunnel slag. Prevents and ensures the safety of existing structures. Only cycle feet are excavated, preventing soil layers and unstable 0.5 to 1.2 meters for rock bodies, 1 to 1.5 meters for stable rock bodies, and 0.5 to 1.2 meters for unstable rock bodies. If the stabilization time of the excavation surface does not meet the initial support construction, pre-support or grout injection will be used. After each cycle of excavation, a shotcrete- Rock bolt support was carried out in a timely manner, and temporary steel supports 32 were erected to support the 3rd basement floor. In this way, the left rail area area 3A on the third basement floor is supported by the second The secondary lining structure 35 was completed, and the temporary support 32 in the left line rail area region 3A on the third basement floor was covered with the secondary lining. Adjust within the construction structure range.

[0035] Step 10.4: Next, as shown in FIG. 4E, the central pilot tunnel 3B and the underground Construct the secondary lining structure for the right-side rail area 3C on the third floor. It has two H-shaped wings. When the construction and sealing of the secondary lining structure 35 on the third basement floor is completed, the temporary steel support 32 is Adjust within the range of the secondary lining structure.

[0036] Step 10.5: As shown in Figure 4F, the secondary lining structure 35 of the third basement floor on both sides was completed. After that, the remaining rock mass 3D in the center was excavated, and similarly excavated by the bench method. The tunnel slag 31 is removed block by block to form a vibration-proof layer, and then explosive excavation is performed. This will prevent the collapse of mortar and tunnel slag and ensure the safety of the existing structure. Excavate only cycle feet, 0.5 to 1.2 meters for soil layers and unstable rocks, and 0.5 to 1.2 meters for stable rocks. The depth is 1 to 1.5 meters inside the body, and the time required for the excavation surface of the unstable rock to stabilize is sufficient for the initial support construction. If not, reinforcement measures will be taken by pre-support or grout injection. Each time excavation is completed, shotcrete-rock bolt supports are provided in a timely manner. Steel supports 32 are erected to support the top plate of the third basement floor.

[0037] Step 10.6: Complete the remaining secondary lining structure for the third basement floor35 and install temporary steel supports. Install 32.

[0038] Step 10.7: Excavate the right-side track section tunnel 34 of subway track B, as shown in FIG. 4G. 3. Install three grid steel frames in parallel, open the in-gate to enter the tunnel, and start excavation. Immediately afterwards, C25 concrete was sprayed to seal the surrounding rocks, and the lattice arch frame and Temporary steel supports are erected, reinforcing mesh is tied in, and concrete is sprayed. In order to ensure the safety of the secondary lining structure, vibration reduction measures are installed before excavation to reduce the vibration of explosions. The speed is strictly controlled within 15mm / s, and mechanical drilling is adopted if necessary. Step 11: As shown in FIG. 4H, after the secondary lining structure 35 of the third basement floor is completed, the subway The remaining interface of track B was excavated, and the shield machine for construction of subway track B was installed. After digging through the station, the temporary steel supports 32 will be gradually removed and the permanent concrete will be installed. The lead pillars 6 are poured into the rail area partition walls 3 and the interior of the platform transfer channel 37, etc. Manufacture structure 8.

[0039] In view of the above, the important steps and advantages of the present invention are as follows: 1. In the underground excavation - cut and cover semi-inverted construction method, the transfer node according to the present invention The cross section of the building is three stories underground, and both the first and second basement floors are constructed using the arch cover method. Underground excavation was used, and the backfill mortar and tunnel slag provided sufficient foundation load capacity. When the secondary lining structure on the mezzanine level on the second basement floor reaches the designed strength, the shield machine on the second layer of the track will be installed. The tunnel will dig through the station, and after the shield machine passes through the station, the tunnel will be dug through the third basement floor. In this way, construction efficiency is maximized, construction time is shortened, and the upper Priority can be given to ensuring early completion of the span nodes. 2. When the tunnel is excavated to the design elevation, mortar and tunnel slag are filled up to the elevation of the bottom of the mezzanine floor. By uniformly compacting the backfilled tunnel slag, uneven loading of the structure is avoided. When backfilling tunnel slag is applied layer by layer and compacted to a compaction density of 93% or more, The layer should be 25-30cm thick. Sand or mixed soil should be used, as these have good permeability. Do not use poor quality soil. This makes it difficult to effectively use the foundation load below the mezzanine level on the second basement floor. This heightens the tunnel height to meet the flatness requirements, and the tunnel is then dug up to two basement floors when the shield machine passes through the station. This can avoid the destruction of the structure due to uneven load bearing of the mezzanine structure or insufficient load bearing force below. do.

[0040] The above explanations and descriptions are merely exemplary and are not intended to limit the disclosure, application, or uses of the present invention. It is clearly not intended to be a limitation on the present invention. However, the present invention is directed to the best mode presently contemplated for carrying out the teachings of the present invention, as illustrated in the drawings. The scope of the present invention is illustrated by the above and is not limited to the specific examples set forth in the Examples. It is intended to include all embodiments that fall within the scope of the description and the appended claims. do. [Explanation of symbols]

[0041] 1 Station building layer 2. Subway Line A Platform Level 3. Subway Track B Platform Level 6. Permanent Concrete Pillars 7 Anchor Rod 11 Pilot tunnel on the left side of the arch 12 Pilot tunnel on the right side of the arch 13 Central pilot tunnel of the arch 14 Rock Bolt 15 Temporary steel arch frame 16 Arched Joist 17 Secondary lining structure using arch covers 18 "L-shaped" joint 19 Mezzanine floor on the first basement floor 21 Left section tunnel of subway track A 22 Right section tunnel of subway track A 23 Mezzanine floor on the second basement floor 24 Secondary sidewall lining structure for basement 1st and 2nd floors 31 Mortar and tunnel slag 32 Temporary Steel Support 33 Left section tunnel of subway track B 34 Right section tunnel of subway track B 35 Secondary lining structure for the 3rd basement floor 36 Interface Ring Beam 37 Transfer channel on the 3rd basement floor 38 Rail Area Partition Wall 3A Left line rail area on the 3rd basement floor 3B: Central pilot tunnel on the 3rd basement floor 3C Right-hand rail area on the 3rd basement floor 3D Remaining rock mass in the center of the 3rd basement floor

Claims

1. The cross section of the station node of the cross-transfer subway is three stories underground, the first story underground is the station building layer, The lower two floors are the platform level for subway line A, the third basement floor is the platform level for subway line B, and the front The track directions of the subway line A and subway line B are perpendicular to each other, and the station building level and the platform level of subway line A are The arch cover method is used for construction of the shield tunnel for section A of the subway line. After Shin had dug through the station, the tunnel was dug under the arch cover by reverse construction. Underground of an interchange subway station where cut and cover construction of the platform layer of subway track B is carried out A drilling-cut and cover semi-inverted construction method, The pilot tunnel on the left side of the arch will be excavated in stages. After excavation is completed, a 40 mm thick concrete tunnel will be installed. The initial spraying of cleat was carried out to seal the surrounding rock, anchor rods were installed, and the lattice art was The temporary steel arch frame of the pilot tunnel on the left side of the arch was placed. Step 1 is to erect the structure and then spray concrete to a thickness of 350 mm. The pilot tunnel on the right side of the arch was excavated in stages, and immediately after excavation was completed, a 40 mm thick core was The initial spraying of concrete was carried out to seal the surrounding rocks, anchor rods were installed, and the lattice structure was A temporary steel arch frame was then installed, and 350 ml of concrete was poured into the arch. Step 2 is to spray the film to a thickness of mm. Excavate the remaining surrounding rock of the central pilot tunnel of the arch of the station and Step 3: installing and fixing a temporary steel arch frame of the tunnel; The bottom base layer is constructed, and once it has reached the desired strength, the arch leg joists on both sides are constructed. Step 4 of manufacturing the Part of the temporary steel arch frame was removed to create a space effect, and a waterproof layer was laid, and the arch cover was installed. Step 5: constructing a secondary lining structure by the above method and leaving a side wall construction joint in advance; When the secondary lining structure using the arch cover reaches the designed strength, a gradient is created and the intermediate layer of core soil is Step 6 of excavating the soil; The surrounding rocks on both sides of the station's middle layer are excavated layer by layer from top to bottom, and excavation is performed step by step to reach the relevant layer. The anchor rod is lowered 0.5m, and the anchor rods on both sides are installed and concrete is poured. Once the installation is complete, step 7 involves further excavation. When excavation was performed to the design elevation, mortar and tunnel slag were piled up to the bottom elevation of the mezzanine on the second basement floor. When the foundation load required for the shield machine to excavate is met, the mezzanine structure and Step 8: Construct the secondary lining structure of the side walls of the first and second basement floors from bottom to top using the pour-in method. and, When the secondary lining structure of the mezzanine on the second basement floor reaches the designed strength, the roadbed will be backfilled and the rails will be laid. Step 9: The shield machine for constructing subway line A digs through the station. and, The left section tunnel of subway line B is used as a construction channel to circulate the platform level of subway line B. The drilling was carried out efficiently, temporary steel supports were installed in a timely manner, and the support was The secondary lining structure for the third basement floor will be constructed in a timely manner, and the secondary Step 10 of proceeding to the next excavation cycle after the construction of the lining structure is completed; After the secondary lining structure on the third basement floor is completed, the remaining interface of subway line B will be excavated. After the shield machine for construction of subway line B has passed through the station, the internal structure is constructed. A method for constructing an intersection transfer type subway station comprising the steps of: Undercutting – Cut and cover semi-reverse construction method.

2. In step 1, at least one pilot tunnel is installed at the arch leg position on the left side of the arch. In step 2, the rock bolts of the pilot tunnel on the right side of the arch are installed.

2. The method according to claim 1, further comprising the steps of: attaching at least one lock bolt to the arch leg position; The underground excavation for the described cross-transfer subway station - cut-and-cover semi-reverse construction method.

3. In the above steps 1 and 2, each pilot tunnel is excavated.

2. The crossing transfer according to claim 1, wherein the tunnel has a foot length of 15 m or more. Underground excavation for E-type subway station – Cut and cover semi-reverse construction method.

4. In step 4, the inner ends of the rock bolts installed in steps 1 and 2 are By pouring concrete into the inside of the arch joist, the stability and reliability of the arch joist are improved. The underground excavation-cabin of the interchange type subway station according to claim 2 is provided. Kit and cover semi-reverse construction method.

5. In the step 5, primary molding is used to construct the secondary lining structure by the arch cover, 4. The method according to claim 3, wherein the joints of the side walls are each provided with an "L"-shaped joint. Underground excavation method for an interchange-type subway station according to claim 1 - cut-and-cover semi-reverse construction method 。

6. In step 6, the slope is created and excavated with a gradient of 1:0.5 or less, and both sides 2. The method according to claim 1, wherein the horizontal distance from the foundation to the top of the slope is 3 m or more. Underground excavation for interchange subway station – Cut and cover semi-reverse construction method.

7. In step 8, mortar and tunnel slag are backfilled and uniformly compacted, and the compaction density is ≧ When compacting at 93%, the thickness of each layer is 25-30 cm, and the side walls of the first and second basement floors are The sub-lining structure and permanent concrete columns are cast to a depth of 500 mm or more below the mezzanine level on the second basement floor. The ratio of pre-retained joints of reinforcing bars in the same cross section is set to 50% or less. The underground excavation of the cross-transfer type subway station according to claim 1 - cut and cover semi-reverse construction Construction method.

8. Step 10 includes the following sub-steps: The left section tunnel of subway line B was used as the construction channel, and the left section of the third basement floor was constructed using the bench construction method. The area of ​​the rail track is excavated in cycle feet, and the excavation of cycle feet is completed. Each time a construction project is completed, the shotcrete-rock bolt support should be carried out in a timely manner to prevent the construction of temporary steel structures. Step 10.1: erecting the support to support the top plate of the third basement floor; Dig from the center to excavate the pilot tunnel in the center of the third basement level, and then similarly Excavation is performed using the cycle method, and only cycle feet are excavated, and excavation for the cycle feet is completed. Each time, the shotcrete-rock bolt supports were carried out in a timely manner, and temporary steel supports were installed. Supports will be erected to support the top plate of the 3rd basement floor, and the left track area of ​​the 3rd basement floor will be Step 10.2, starting to gradually build a secondary lining structure of the third basement level of the area; Open the tunnel from both sides and measure the area of ​​the right-hand rail area on the third basement floor in cycle feet. Excavation is performed and shotcrete-rockbolt is applied every time a cycle foot of excavation is completed. The shoring work was carried out in a timely manner, and temporary steel supports were erected to support the top plate of the third basement floor. By doing so, the secondary lining structure of the third basement floor in the area of ​​the left track rail area on the third basement floor will be completed, and the underground Step 10: Adjust the temporary support in the left rail area on the third floor to within the secondary lining structure range. . 3 and Next, the secondary lining structure for the central pilot tunnel and the right-side rail area on the third basement floor After the secondary lining structure on the third basement floor was constructed and sealed, temporary steel supports were installed. Step 10.4 of adjusting the secondary lining structure range; The remaining rock mass in the center was excavated, and similarly, bench excavation was performed, and only cycle feet were excavated. Cut and cycle each foot of excavation completed with shotcrete-rock bolts The shoring was carried out in a timely manner, and temporary steel supports were erected to support the top plate of the third basement floor. Step 10.5 and Step 10: Complete the remaining secondary lining structure on the third basement floor and install temporary steel supports .6 and Excavate a tunnel for the right section of subway line B and install three grid steel frames in parallel. Immediately after excavation, C25 concrete was sprayed to seal the surrounding rocks and a lattice arch frame was installed. The tower and temporary steel supports are erected, the reinforcing steel mesh is tied in, and concrete is sprayed. Step 10.

7. Underground excavation for interchange-type subway station – Cut-and-cover semi-reverse construction method.

9. In steps 10.1, 10.2, 10.3 and 10.5, the cylindrical layer is used in soil and unstable rocks. The cycle feet are 0.5 to 1.2 meters, and within the stable rocks the cycle feet are 1 to 2 meters. 1.5 meters, and the stabilization time for the excavation surface of the unstable rock mass does not meet the initial support construction.

9. The method according to claim 8, characterized in that, in the event of a flood, reinforcement measures are taken by pre-support or grout injection. Underground excavation for interchange subway station – Cut and cover semi-reverse construction method.

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