Construction method for newly-built subway station to underpass operating subway station at zero distance

Abstract

The invention discloses a construction method for a newly-built subway station to underpass an operating subway station at zero distance, belongs to the technical field of underground engineering, and aims to overcome the defects of many pilot tunnels, poor settlement control, slow construction progress and the like of the traditional newly-built subway station which adopts mining method block underground excavation and passive underpinning structure to underpass the operating subway station. A vertical supporting pilot tunnel and a side wall pilot tunnel are excavated under the operation subway station to serve as a construction channel to construct an active underpinning system; the active underpinning system comprises a temporary supporting pile, a jack, a temporary transverse support, a newly-built side wall of the newly-built subway station and a top plate hidden beam, the temporary supporting pile is arranged in the vertical supporting pilot tunnel, the jack is installed at the top end of the temporary supporting pile, and the top plate hidden beam is supported at the top end of the jack; and under the support of the active underpinning system, the operating subway station is used as a cover plate, and a cover-excavation sequential construction method is used for constructing a newly-built subway station. The underground excavation method pilot tunnel engineering cost is effectively reduced, the construction efficiency is improved, and the construction safety is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of underground engineering, and in particular relates to a construction method for a new subway station to pass under an operating subway station at zero distance. Background Art

[0002] With the continuous increase in subway line planning, considering the connection, transfer and economy of new subway lines and existing lines, it is inevitable that new subway stations will pass under existing subway stations at zero distance. Since the existing subway lines have been put into operation, the settlement of the existing station structures and lines is strictly controlled, and the subway station structures are relatively wide. They are highly sensitive to the construction disturbance (especially settlement values) caused by the new station passing under. Conventional mining construction methods have large excavation sections, insufficient initial support stiffness and long closed loop time, which can easily cause the settlement of the existing station structure above to exceed the limit, affecting operational safety.

[0003] The small-section mining method can address these issues to a certain extent, but it also presents challenges such as multiple block structures, complex load transfer, limited construction equipment, heavy workload in the initial use and removal of supporting steel frames, and slow construction progress. Traditional underpasses mostly utilize passive underpinning structures (without settlement compensation devices between the old and new station structures). Therefore, sudden changes in the existing station's settlement are inevitable during construction as loads transfer between the old and new structures. Summary of the Invention

[0004] The purpose of the present invention is to provide a construction method for a newly built subway station to pass under an operating subway station at zero distance, so as to solve the shortcomings of traditional newly built subway stations that use mining methods to excavate blocks and passively replace structures to pass under operating subway stations, such as multiple pilot tunnels, poor settlement control, and slow construction progress.

[0005] A construction method for a new subway station passing under an operating subway station at zero distance comprises: secretly excavating vertical support guide holes and side wall guide holes under the operating subway station as construction channels to construct an active underpinning system; the active underpinning system comprises temporary support piles, jacks, temporary lateral supports, new side walls of the new subway station, and hidden roof beams of the new subway station; the temporary support piles are arranged in the vertical support guide holes; the jacks are installed on the top ends of the temporary support piles; the hidden roof beams are part of the permanent roof of the new subway station and are supported on the top ends of the jacks; the temporary lateral supports connect the new side walls and the temporary support piles together; under the support of the active underpinning system, the new subway station is constructed using the cover-excavation method with the operating subway station as the cover.

[0006] Further, the following steps are included:

[0007] Step 1: Pre-reinforce the ground around the new subway station;

[0008] Step 2: Excavate a vertical support pilot tunnel under the operating center column and operating side wall of the operating subway station; construct roof slab hidden beams, temporary support piles, and jacks in the vertical support pilot tunnel at locations corresponding to the operating center column and operating side wall, with the jacks installed on top of the temporary support piles; the roof slab hidden beams are special parts of the newly built roof, supported on the tops of the jacks and resting against the floor of the operating subway station. The roof slab hidden beams, temporary support piles, and jacks form a vertical force-transmitting member that directly supports the operating subway station;

[0009] Step 3: Excavate the side wall pilot holes on both sides of the new subway station, and construct the new side walls of the new subway station in the side wall pilot holes. After the new side walls are completed, set up temporary transverse supports. The two ends of the temporary transverse supports are anchored to the new side walls of the new subway station, and the middle part is fixedly connected to the temporary support piles through connectors.

[0010] Step 4: Under the support of the active underpinning system consisting of top slab concealed beams, temporary support piles, jacks, new side walls, and temporary transverse supports, use the operating subway station as a cover to cover the remaining soil for the new subway station, and complete the construction of the new base slab, new partition walls, and new top slab of the new subway station, so that the new side walls, new base slab, new top slab, and new partition walls form the main structure of the new subway station;

[0011] Step 5: Remove the temporary support system.

[0012] Furthermore, the temporary transverse support is a steel truss structure or a steel pipe support frame.

[0013] Furthermore, the connecting member is an I-shaped member or a groove-shaped member.

[0014] Furthermore, in step five, the temporary lateral supports are first removed, then the temporary support piles under the operating side walls of the operating subway station are removed, and finally the temporary support piles under the operating center columns of the operating subway station are removed.

[0015] Furthermore, in step three, the side wall pilot hole is excavated in two layers, the upper side wall pilot hole is excavated first, and the upper side wall pilot hole is initially supported; then the lower side wall pilot hole is excavated, and the lower side wall pilot hole is initially supported.

[0016] Furthermore, in steps 2 to 4, the displacement data of the operating subway station is monitored in real time by a fully automatic monitoring instrument, and the jacking force of the jack is dynamically adjusted based on the monitored displacement data.

[0017] Furthermore, the initial jacking force F was set to 0.85f, where f is the theoretical axial force of the operating subway station column above the jack. The displacement threshold d was set to 10mm, the differential settlement threshold δ was set to 0.001Lmm, and L was the longitudinal spacing of the jacks along the operating subway station. The rate of change threshold v was set to 2mm / d. The displacement data d was obtained in real time using a fully automatic monitoring instrument, and the differential settlement δ and rate v were calculated.

[0018] Next, the intelligent decision module receives the displacement, differential settlement, and velocity, determines the response level, and transmits the corresponding level to the jack;

[0019] When any two of the following conditions are met: 4mm<d≤6mm, 0.0004Lmm<δ≤0.0006Lmm, 0.8mm / d<v≤1.2mm / d, the first-level warning response is implemented: the jacking force F is increased by 10%;

[0020] When any two of the following conditions are met: 6mm<d≤8mm, 0.0006Lmm<δ≤0.0008Lmm, 1.2mm / d<v≤1.6mm / d, the second-level warning response is implemented: the jacking force is increased by 15%;

[0021] When any two of the following conditions are met: d>8mm, δ>0.0008Lmm, and v>1.6mm / d, a Level 3 warning response will be implemented: excavation operations will be suspended, the jacking force will be increased by 30%, and temporary vertical steel supports will be erected for reinforcement.

[0022] Finally, the jacks perform actions according to the corresponding level.

[0023] The beneficial effects of the present invention are as follows: The disclosed method for constructing a new subway station under an operating subway station at zero distance utilizes a concealed vertical support pilot tunnel and a side wall pilot tunnel as construction channels, and only an active underpinning system is constructed. The new station is supported by the active underpinning system, which comprises roof beams, temporary support piles, jacks, new side walls, and temporary lateral supports. With the operating subway station as the cover, construction can be carried out using a cover-and-excavation method. This effectively reduces the cost of the concealed pilot tunnel construction, improves construction efficiency, and ensures construction safety.

[0024] Fully automatic monitoring instruments are used to conduct uninterrupted real-time monitoring of the operating lines. By setting monitoring control values, feedback and analysis of monitoring data, the jacking force is finally adjusted, forming a closed-loop control of "monitoring-feedback-regulation", achieving the goal of accurately controlling the settlement of existing lines (≤0.5mm) and ensuring the safety of operating lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A construction longitudinal section drawing of a new subway station passing under an operating subway station at zero distance;

[0026] Figure 2 This is a cross-sectional view of the vertical support guide tunnel construction for the new subway station to pass under the operating subway station at zero distance;

[0027] Figure 3 Cross-sectional view of the temporary support pile construction for the new subway station to pass under the operating subway station at zero distance;

[0028] Figure 4 This is a cross-sectional diagram of the construction of a pilot tunnel for a new subway station to pass under the side wall of an operating subway station at zero distance;

[0029] Figure 5 Cross-sectional drawing of the construction of new side walls of the new subway station with zero distance underpass of the operating subway station;

[0030] Figure 6 Cross-sectional drawing of temporary lateral support construction for a new subway station passing under an operating subway station at zero distance;

[0031] Figure 7 Cross-sectional drawing of the excavation and cover of the new subway station passing under the operating subway station at zero distance;

[0032] Figure 8 This is a cross-sectional diagram of the construction of a new subway station that will pass under an operating subway station at zero distance;

[0033] Figure 9 Cross-sectional view of the new subway station after the temporary supports were removed for the station to pass under the operating subway station at zero distance.

[0034] In the figure, there is an operating subway station 1, an operating central column 100, an operating side wall 110, a vertical support guide hole 2, temporary support piles 3, a jack 4, a top plate hidden beam 5, a side wall guide hole 6, a new side wall 7, a connector 8, a temporary horizontal support 9, a new bottom plate 11, a new top plate 12, and a new partition wall 13. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0036] A construction method for a new subway station to pass under an existing subway station at zero distance comprises the following steps:

[0037] Step 1: Pre-reinforce the ground around the new subway station;

[0038] Step 2: Figure 1 、 Figure 2 and Figure 3As shown, a vertical support pilot tunnel 2 is excavated beneath the locations of the operational columns 100 and operational side walls 110 of the operating subway station 1. Within the vertical support pilot tunnel 2, corresponding to the operational columns 100 and operating side walls 110, a roof slab concealed beam 5, temporary support piles 3, and jacks 4 are constructed. The jacks 4 are mounted on top of the temporary support piles 3. The roof slab concealed beam 5 is a special part of the newly constructed roof slab 12, supported on top of the jacks 4 and resting against the floor of the operating subway station 1. The roof slab concealed beam 5, temporary support piles 3, and jacks 4 form a vertical force-transmitting member that directly supports the operating subway station 1. The roof slab concealed beam 5 is a special part of the newly constructed roof slab 12. First, it is a permanent part of the newly constructed roof slab 12. Second, it is constructed prior to the newly constructed roof slab 12. In its early stages, it also serves as part of the active underpinning system, directly supporting the operating subway station 1.

[0039] Step 3: Figure 4 and Figure 5 As shown, the side wall guide holes 6 on both sides of the new subway station are excavated, and the new side walls 7 of the new subway station are constructed in the side wall guide holes 6, as shown in FIG. Figure 6 As shown, after the new side wall 7 is completed, a temporary transverse support 9 is erected. Both ends of the temporary transverse support 9 are anchored to the new side wall 7 of the new subway station, and the middle part is fixedly connected to the temporary support pile 3 through a connector 8;

[0040] Step 4: Figure 7 As shown, under the support of the active underpinning system consisting of the top plate hidden beam 5, temporary support piles 3, jacks 4, new side walls 7 and temporary transverse supports 9, the operating subway station 1 is used as the cover plate, and the remaining soil of the new subway station is excavated using the cover-and-excavation method. Figure 8 As shown, the construction of the new base plate 11, the new partition wall 13 and the new top plate 12 of the new station is completed, so that the new base plate 11, the new partition wall 13 and the new top plate 12 form the main structure of the new subway station;

[0041] Step 5: Figure 9 As shown, the temporary support system is dismantled. The temporary support system includes temporary support piles 3, jacks 4 and temporary lateral supports 9.

[0042] Vertical jacks installed beneath the operational columns 100 and operational sidewalls 110 actively support the operational subway station 1. Temporary lateral supports 9 and newly constructed sidewalls 7 form a support system for horizontal earth pressure. The synergistic effect of the active vertical jack support and the lateral support system effectively achieves direct force conversion and precise control of settlement during excavation. The new station, protected by the active support system, utilizes a cover-and-cut method, reducing project costs, significantly improving efficiency, and shortening construction schedules.

[0043] The jacks 4 are arranged on the temporary support piles 3 , and can accurately control the structural settlement value of the operating subway station 1 in real time, thereby ensuring the operational safety of the operating subway station 1 .

[0044] Vertical support pilot tunnels 2 are located beneath the operating center column 100 and the operating side wall 110. This targeted placement of pilot tunnels reduces excavation effort. Jacks 4 are located at these critical load-bearing points, improving jacking force control accuracy and enabling precise control of existing line settlement within the required engineering range. The pilot tunnels on both sides of the side walls form a closed framework, controlling differential station settlement within the required engineering range.

[0045] Preferably, the temporary lateral supports 9 are constructed of steel trusses, or steel pipes. Steel trusses provide high-rigidity horizontal restraint, effectively dissipating earth pressure and reducing the risk of deformation in operational stations. The connectors 8 are I-shaped or channel-shaped, such as I-beams or channel steels, or can be fabricated on-site from steel plates.

[0046] In step five, the temporary horizontal supports 9 are first removed, followed by the temporary support piles 3 beneath the operational side walls 110 of the operating subway station 1, and finally, the temporary support piles 3 beneath the operational central columns 100 of the operating subway station 1. This method of dismantling the horizontal support first, then the side walls, and finally the columns has been verified on-site to minimize incremental settlement during the demolition phase, keeping it under 1mm. This distributed stress release significantly reduces the risk of support instability and provides enhanced safety and protection.

[0047] Preferably, in step three, the side wall guide hole 6 is excavated in two layers, the upper side wall guide hole 6 is excavated first, and the upper side wall guide hole 6 is initially supported; then the lower side wall guide hole 6 is excavated, and the lower side wall guide hole 6 is initially supported.

[0048] In step 2 to step 4, the displacement data of the operating subway station 1 is monitored in real time by a fully automatic monitoring instrument, and the jacking force of the jack 4 is dynamically adjusted based on the monitored displacement data.

[0049] Automated monitoring and real-time jacking force adjustment ensure precise control of settlement and guarantee safe operation.

[0050] The specific process is:

[0051] First, the initial jacking force F was set to 0.85f, where f is the theoretical axial force of the operating subway station column above the jack. The displacement threshold d was set to 10mm, the differential settlement threshold δ was set to 0.001Lmm, and L was the longitudinal spacing of the jacks along the operating subway station. The rate of change threshold v was set to 2mm / d. Displacement data d was obtained in real time using a fully automatic monitoring instrument, and the differential settlement δ and rate v were calculated.

[0052] Next, the intelligent decision module receives the displacement, differential settlement and velocity, determines the response level, and transmits the corresponding level to the jack 4;

[0053] When any two of the following conditions are met: 4mm<d≤6mm, 0.0004Lmm<δ≤0.0006Lmm, 0.8mm / d<v≤1.2mm / d, the first-level warning response is implemented: the jacking force F is increased by 10%;

[0054] When any two of the following conditions are met: 6mm<d≤8mm, 0.0006Lmm<δ≤0.0008Lmm, 1.2mm / d<v≤1.6mm / d, the second-level warning response is implemented: the jacking force is increased by 15%;

[0055] When any two of the following conditions are met: d>8mm, δ>0.0008Lmm, and v>1.6mm / d, a Level 3 warning response will be implemented: excavation operations will be suspended, the jacking force will be increased by 30%, and temporary vertical steel supports will be erected for reinforcement.

[0056] Finally, Jack 4 performs actions according to the corresponding level.

[0057] The three-level response mechanism, consisting of level one, level two, and level three early warning responses, provides risk prevention and control capabilities, significantly reducing the rate of excessive settlement accidents. Compared with traditional manual response methods, the automated monitoring and timely force adjustment system of this invention can control the time from monitoring to execution to within 2 minutes, achieving a fast response speed.

[0058] In the description of this specification, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc. should be understood broadly. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can also mean internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0059] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A construction method for a new subway station to pass under an existing subway station at zero distance, characterized by: Under the operating subway station (1), a vertical support guide hole (2) and a side wall guide hole (6) are secretly excavated as a construction channel to construct an active underpinning system; the active underpinning system includes temporary support piles (3), jacks (4), temporary transverse supports (9), a new side wall (7) of the new subway station, and a top plate hidden beam (5) of the new subway station, the temporary support piles (3) are arranged in the vertical support guide hole (2), the jacks (4) are installed on the top of the temporary support piles (3), the top plate hidden beam (5) is a part of the permanent top plate of the new subway station and is supported on the top of the jacks (4), and the temporary transverse supports (9) connect the new side wall (7) and the temporary support piles (3) together; under the support of the active underpinning system, the operating subway station (1) is used as a cover plate, and the new subway station is constructed by a cover-excavation method.

2. A construction method for a new subway station to pass under an existing subway station at zero distance, characterized by: The following steps are involved: Step 1: Pre-reinforce the ground around the new subway station; Step 2: excavate a vertical support guide hole (2) under the position of the operating center column (100) and the operating side wall (110) of the operating subway station (1); and construct a top plate hidden beam (5), a temporary support pile (3) and a jack (4) in the vertical support guide hole (2) at the position corresponding to the operating center column (100) and the operating side wall (110), wherein the jack (4) is installed at the top of the temporary support pile (3); the top plate hidden beam (5) is a special part of the newly built top plate (12), supported on the top of the jack (4) and against the bottom plate of the operating subway station (1), and the top plate hidden beam (5), the temporary support pile (3) and the jack (4) form a vertical force transmission component that directly supports the operating subway station (1); Step 3: excavate the side wall guide holes (6) on both sides of the new subway station, and construct the new side wall (7) of the new subway station in the side wall guide holes (6). After the new side wall (7) is completed, a temporary transverse support (9) is erected. Both ends of the temporary transverse support (9) are anchored to the new side wall (7) of the new subway station, and the middle part is fixedly connected to the temporary support pile (3) through a connector (8); Step 4: Under the support of the active underpinning system composed of the top plate hidden beam (5), temporary support piles (3), jacks (4), new side walls (7) and temporary transverse supports (9), the operating subway station (1) is used as a cover plate to cover the remaining soil of the new subway station, and the construction of the new base plate (11), new partition wall (13) and new top plate (12) of the new subway station is completed, so that the new side walls (7), new base plate (11), new top plate (12) and new partition wall (13) form the main structure of the new subway station; Step 5: Remove the temporary support system.

3. The construction method for a new subway station to pass under an existing subway station at zero distance as claimed in claim 2, characterized in that: The temporary transverse support (9) is a steel truss structure or a steel pipe support frame.

4. A construction method for a new subway station to pass under an existing subway station at zero distance as claimed in claim 1, 2 or 3, characterized in that: The connecting member (8) is an I-shaped member or a groove-shaped member.

5. The construction method for a new subway station to pass under an existing subway station at zero distance as described in claim 2 or 3, characterized in that: In step five, the temporary lateral support (9) is first removed, then the temporary support piles (3) under the operating side wall (110) of the operating subway station (1) are removed, and finally the temporary support piles (3) under the operating center column (100) of the operating subway station (1) are removed.

6. The construction method for a new subway station to pass under an existing subway station at zero distance according to claim 2 or 3, characterized in that: In step 3, the side wall pilot hole (6) is excavated in two layers, the upper side wall pilot hole (6) is excavated first, and the upper side wall pilot hole (6) is initially supported; then the lower side wall pilot hole (6) is excavated, and the lower side wall pilot hole (6) is initially supported.

7. The construction method for a new subway station to pass under an existing subway station at zero distance as claimed in claim 2 or 3, characterized in that: In steps 2 to 4, the displacement data of the operating subway station (1) is monitored in real time by a fully automatic monitoring instrument, and the jacking force of the jack (4) is dynamically adjusted based on the monitored displacement data.

8. The construction method for a new subway station to pass under an existing subway station at zero distance as claimed in claim 7, characterized in that: First, the initial jacking force F was set to 0.85f, where f is the theoretical axial force of the operating subway station column above the jack. The displacement threshold d was set to 10mm, the differential settlement threshold δ was set to 0.001Lmm, and L was the longitudinal spacing of the jacks along the operating subway station. The rate of change threshold v was set to 2mm / d. Displacement data d was obtained in real time using a fully automatic monitoring instrument, and the differential settlement δ and rate v were calculated. Then, the intelligent decision module receives the displacement, differential settlement and velocity, determines the response level, and transmits the corresponding level to the jack (4); When any two of the following conditions are met: 4mm<d≤6mm, 0.0004Lmm<δ≤0.0006Lmm, 0.8mm / d<v≤1.2mm / d, the first-level warning response is implemented: the jacking force F is increased by 10%; When any two of the following conditions are met: 6mm<d≤8mm, 0.0006Lmm<δ≤0.0008Lmm, 1.2mm / d<v≤1.6mm / d, the second-level warning response is implemented: the jacking force is increased by 15%; When any two of the following conditions are met: d>8mm, δ>0.0008Lmm, and v>1.6mm / d, a Level 3 warning response will be implemented: excavation operations will be suspended, the jacking force will be increased by 30%, and temporary vertical steel supports will be erected for reinforcement. Finally, the jack (4) performs the action according to the corresponding level.

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