Arch support construction method in tunnel excavation mode

Abstract

The invention relates to the field of bridge construction, in particular to a tunnel excavation type skewback construction method which comprises the following steps: partitioning a skewback foundation into an upper tunnel, a middle tunnel and a lower tunnel; slope excavation is conducted to the bottom face position of a middle tunnel outlet, and a construction platform is formed; a middle tunnel advance support is constructed, a middle tunnel is excavated, and the excavation direction is from the river center to the bank side; after the middle tunnel is excavated in place, the lower tunnel is excavated; an arch support foundation lower area and a backfill area are poured in the middle tunnel and the lower tunnel; after concrete in the lower area and the backfill area of the skewback foundation is formed, an upper tunnel is excavated, and the excavation direction is from the river center to the bank side; according to the method, firstly, the skewback foundation is partitioned, then tunnel excavation is adopted for each partition, the skewback foundation is formed through pouring, the natural sloping excavation amount can be reduced, the spoil amount can be reduced, and the influence on the environment is small.

Description

Technical Field

[0001] The invention relates to the field of bridge construction, and in particular to an arch seat construction method in a tunnel excavation manner. Background Art

[0002] With the development of construction technology, the span of arch bridges continues to increase, and the terrain and location conditions in which they are applicable are also increasing. Among them, the construction of traditional arch foundations requires huge excavation projects, which not only destroys vegetation and the environment, but also requires a large spoil site, which increases transportation distance and construction costs.

[0003] Therefore, a technical solution is currently needed to solve the technical problems that the construction of the arch seat requires a huge excavation project, a long construction period, high construction costs, and environmental damage. Summary of the invention

[0004] The purpose of the present invention is to overcome the technical problems in the prior art that arch seat construction requires huge excavation engineering, has a long construction period, high construction cost and causes environmental damage, and to provide an arch seat construction method in a tunnel excavation mode.

[0005] The present invention provides an arch seat construction method in a tunnel excavation mode, comprising the following steps: S1: Divide the abutment foundation into upper tunnel, middle tunnel and lower tunnel; S2: Slope excavation to the bottom of the middle tunnel exit to form a construction platform; S3: construct the middle tunnel advance support and excavate the middle tunnel, with the excavation direction from the river center to the bank side; S4: After the middle tunnel is excavated, the lower tunnel is excavated; S5: Casting of the lower area of ​​the abutment foundation and the backfill area in the middle tunnel and the lower tunnel; S6: After the concrete of the lower area of ​​the arch foundation and the backfill area is formed, the upper tunnel is excavated from the river center to the bank side; S7: Casting of the upper zone of the abutment foundation in the upper tunnel.

[0006] The invention discloses an arch seat construction method in a tunnel excavation mode. S1 divides the arch seat foundation into zones so as to facilitate subsequent tunnel excavation for each zone. S2 forms a construction platform by slope excavation at the tunnel mouth to facilitate the excavation and construction of the middle tunnel. S3 performs advanced support during the excavation of the middle tunnel to ensure the safety of the middle tunnel construction. S4 only needs to construct an inverted arch support once, so that the tunnel top is subjected to less pressure. S5 builds the lower zone and backfill zone of the arch seat foundation after the excavation of the middle tunnel and the lower tunnel is completed to provide a foundation for the construction of the upper tunnel. S6 and S7 excavate the upper tunnel and pour concrete to facilitate the connection of the arch seat frame frame to complete the arch seat construction.

[0007] Preferably, in step S3, a cross-shaped support frame is arranged in the middle tunnel, and the cross-shaped support frame divides the middle tunnel into four relatively independent small chambers, and excavation construction is performed separately.

[0008] The middle tunnel occupies the largest area of ​​the arch foundation. Dividing the excavation construction in this area into four independent small chambers for separate construction can improve the safety of the construction process.

[0009] Preferably, in step S4, the excavation direction of the lower tunnel is from the bank side to the river center.

[0010] After the excavation of the middle tunnel is completed, the equipment and facilities are all at the inner end of the tunnel. Therefore, the lower tunnel is excavated in reverse from the inside to the outside, which can reduce the movement of equipment, facilities and personnel, improve the convenience of the construction process, and improve construction efficiency.

[0011] Preferably, in step S4, the lower tunnel entrance is excavated by slope reduction so that the construction platform is moved to the bottom surface of the lower tunnel entrance.

[0012] The side of the lower tunnel close to the river center is excavated with slope to ensure the stability of the lower tunnel structure, so as to facilitate the casting of the lower foundation of the arch seat in the later stage.

[0013] Preferably, in step S5, a first interface connecting steel bar is arranged on the top surface of the lower area of ​​the abutment foundation.

[0014] The connection between the lower area of ​​the abutment foundation and the upper area of ​​the abutment foundation is improved and stabilized.

[0015] Preferably, in step S5, after the concrete of the lower area (6) and the backfill area (7) of the arch seat foundation is formed, the first interface connecting steel bars (8) are connected, and in step S7, before pouring the upper area of ​​the arch seat, the first interface connecting steel bars (8) are bent straight.

[0016] Avoid the first interface connecting steel bars from affecting the excavation construction of the upper tunnel.

[0017] Preferably, in step S5, a gap is left between the top of the lower area (6) of the abutment foundation and the top of the middle tunnel (2).

[0018] Providing space for pouring construction of the lower area of ​​the arch seat foundation and the backfill area is conducive to the smooth construction of the lower area of ​​the arch seat foundation.

[0019] Preferably, the upper area of ​​the arch foundation includes a base portion close to the mountain and an installation portion close to the river center, and the installation portion is used to connect the arch positioning frame. In step S7, the base portion of the upper area of ​​the arch foundation is cast first.

[0020] After the excavation of the upper tunnel is completed, the base part does not need to be connected to the arch frame, so it does not need precise positioning. This part is cast into shape first, which can support the mountain and reduce the impact of subsequent slope construction on the upper tunnel structure.

[0021] Preferably, during the casting process of the base part, a second interface connecting steel bar is arranged on the side of the base part close to the river center.

[0022] The connection between the base portion and the mounting portion in the upper region of the lifting abutment foundation is stable.

[0023] Preferably, in step S7, after the concrete of the base part is formed, the base part is excavated to the end close to the river center, and then the installation part is poured.

[0024] Adding slope excavation to the installation part of the arch seat upper foundation can make the installation part completely exposed to facilitate accurate positioning with the arch seat frame.

[0025] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a tunnel excavation method for arch seat construction, which first divides the arch seat foundation into zones, then excavates the tunnel for each zone, and casts the arch seat foundation, which can reduce the amount of natural slope excavation, reduce the amount of abandoned soil, and have less impact on the environment; 2. The tunnel excavation arch seat construction method provided by the present invention does not require a large amount of slope construction and has a shorter construction period; 3. The present invention provides an arch seat construction method of a tunnel excavation method, wherein the arch seat foundation is excavated in the order of a middle tunnel, a lower tunnel and an upper tunnel, and the upper tunnel is constructed after the concrete of the lower area of ​​the arch seat foundation and the backfill area of ​​the arch seat foundation are formed, and the lower area of ​​the arch seat foundation and the backfill area of ​​the arch seat foundation provide support for the upper tunnel, thereby improving the safety of the upper tunnel construction; 4. The present invention provides an arch seat construction method in a tunnel excavation mode. In the arch seat foundation lower area and the arch seat foundation backfill area, the arch seat foundation backfill area is first constructed (that is, the middle tunnel is excavated first and then the lower tunnel is excavated). The pressure on the tunnel top is smaller, and only one invert arch support is required. The construction process is simpler and the construction safety is higher. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram of the partitioning of the abutment foundation in step S1; Figure 2 is a schematic diagram of the construction of the middle tunnel in steps S2-S3; Figure 3 is a cross-sectional schematic diagram of the construction of the middle tunnel in step S3; Figure 4 is a schematic diagram of the lower tunnel construction in step S4; Figure 5 is a construction schematic diagram of the lower area of ​​the abutment foundation and the backfill area in step S5; Figure 6 is a schematic diagram of the construction of the upper tunnel in step S6; Figure 7 is a schematic diagram of the pouring construction of the base part of the arch base in step S8; Figure 8 is a schematic diagram of the slope construction of the installation part of the upper area of ​​the abutment foundation in step S8; Fig. 9 is a schematic diagram of the pouring construction of the installation part of the upper area of ​​the abutment foundation in step S8; Fig.10 It is a construction diagram of the upper area of ​​the abutment foundation and the abutment frame in step S8.

[0027] Markings in the figure: 1-upper tunnel, 2-middle tunnel, 3-lower tunnel, 4-access road, 5-cross-shaped support frame, 6-lower area of ​​arch foundation, 7-backfill area, 8-first interface connecting steel bars, 9-base part, 10-second interface connecting steel bars, 11-installation part, 12-arch positioning frame. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0029] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0030] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0031] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0032] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0033] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0034] Example 1 The present invention provides a tunnel excavation method for abutment construction, comprising the following steps: 1) Combined with the topography and geology, as well as the location of the construction access road and the construction platform, the arch foundation is divided into areas, namely the arch foundation lower area 6 and the arch foundation upper area. The arch foundation lower area 6 corresponds to the lower tunnel 3 and the middle tunnel 2 on the mountain, and the arch foundation upper area corresponds to the upper tunnel 1 on the mountain. Figure 1 shown.

[0035] 2) Slope excavation to the bottom of the middle tunnel exit 2 to form a construction platform, such as Figure 2 shown.

[0036] 3) Two large pipe sheds were used for advance support of the tunnel in the middle of the construction, including steel frames, pipe sheds, arches, locking steel pipes, etc.

[0037] 4) Excavation of the middle tunnel 2, the excavation direction is from the river center to the bank side. When excavating the tunnel, divide the large-section tunnel into 4 relatively independent small caverns for construction. Follow the construction principle of "small division, short steps, short circulation, fast closure, frequent measurement, and strong support", from top to bottom, divide into blocks into rings, support as you dig, and do a good job of initial support in time. After the settlement and convergence of the arch of the initial support structure are basically stable, remove the temporary middle partition wall and temporary invert in the initial support structure from top to bottom, and then proceed with construction. The middle support is composed of a small guide tube, a steel frame, a steel mesh and shotcrete. The temporary invert is composed of a steel frame and shotcrete. The temporary bottom plate is plain concrete, such as Figure 2 and Figure 3 shown.

[0038] 5) After the middle tunnel 2 is excavated, construction is carried out from the inner end of the middle tunnel downwards, and then the lower tunnel 3 is excavated from the inside to the outside. While the lower tunnel 3 is excavated, the temporary bottom plate of the middle tunnel 2 is broken and the bottom plate of the lower tunnel 3 is constructed. The bottom plate of the lower tunnel 3 is steel concrete. Figure 4 shown.

[0039] 6) The 3rd opening of the lower tunnel is excavated with slope, so that the construction platform is moved to the bottom surface of the 3rd opening of the lower tunnel. Figure 4 shown.

[0040] 7) The lower area 6 of the arch foundation and the backfill area 7 are fully poured with concrete in the lower tunnel 3 and the middle tunnel 2. The lower area 6 of the arch foundation is located on the side close to the mountain, and the backfill area 7 is located on the side close to the river center. The top surface of the lower area 6 of the arch foundation is provided with a first interface connecting steel bar 8. A gap of 2.5m is left between the lower area 6 of the arch foundation and the top of the middle tunnel to facilitate the entry of operators for construction. Figure 5 shown.

[0041] 8) After the concrete of the lower area 6 and the backfill area 7 of the arch foundation is formed, the first interface connecting steel bar 8 is bent and the upper tunnel 1 is excavated. The upper tunnel 1 adopts the advance support of the construction large pipe shed, including steel frame, pipe shed, sleeve arch, locking foot steel pipe, etc. The support of the upper tunnel 1 can adopt the same level or slightly weaker support form as the middle tunnel 2 according to the depth of the covering soil and the stress condition of the soil field, such as Figure 6 shown.

[0042] 9) The upper part of the arch foundation is divided into two parts, one is the base part 9 without the arch frame 12, and the other is the installation part 11 with the arch positioning frame 12. The former area can be directly poured with concrete, and the second interface connecting steel bars 10 are set on the side of the base part 9 near the river. The latter area needs to be accurately positioned before the first segment of the arch rib is erected, and the slope excavation method is adopted for construction, such as Figure 6 , Figure 7 , Figure 8 and Fig. 9 shown.

[0043] 10) Bend the first interface connecting steel bar 8 straight, then cast the installation part 11 of the upper area of ​​the arch seat foundation, pay attention to pre-embed the junction pier steel bar and the arch seat positioning frame 12, such as Fig.10 shown.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A tunnel excavation method for abutment construction, characterized in that: The steps include: S1: Divide the abutment foundation into the upper tunnel (1), the middle tunnel (2) and the lower tunnel (3); S2: Slope excavation to the bottom of the middle tunnel (2) exit to form a construction platform; S3: construct the middle tunnel (2) with advance support and excavate the middle tunnel (2), with the excavation direction from the river center to the bank side; S4: After the middle tunnel (2) is excavated, the lower tunnel (3) is excavated; S5: Casting the lower area (6) of the abutment foundation and the backfill area (7) in the middle tunnel (2) and the lower tunnel (3); S6: After the concrete of the lower area (6) of the abutment foundation and the backfill area (7) is formed, the upper tunnel (1) is excavated in the direction from the river center to the bank side; S7: Casting the upper area of ​​the abutment foundation in the upper tunnel (1).

2. The method for constructing an abutment in a tunnel excavation method according to claim 1, characterized in that: In step S3, a cross-shaped support frame (5) is arranged in the middle tunnel (2), and the cross-shaped support frame (5) divides the middle tunnel (2) into four relatively independent small caverns, and excavation construction is performed separately.

3. The method for constructing an abutment in a tunnel excavation method according to claim 1, characterized in that: In step S4, the lower tunnel (3) is excavated in a direction from the bank to the river center.

4. The method for constructing an abutment in a tunnel excavation method according to claim 1, characterized in that: In step S4, the lower tunnel entrance is sloped and excavated so that the construction platform is moved to the bottom surface of the lower tunnel entrance.

5. The method for constructing an abutment in a tunnel excavation method according to claim 1, characterized in that: In step S5, a first interface connecting steel bar (8) is arranged on the top surface of the lower area (6) of the abutment foundation.

6. The method for constructing an abutment in a tunnel excavation method according to claim 5, characterized in that: In the step S5, after the concrete of the lower area (6) and the backfill area (7) of the arch seat foundation is formed, the first interface connecting steel bars (8) are connected. In the step S7, before pouring the upper area of ​​the arch seat, the first interface connecting steel bars (8) are bent straight.

7. The method for constructing an abutment in a tunnel excavation method according to claim 1, characterized in that: In step S5, a gap is left between the top of the lower area (6) of the abutment foundation and the top of the middle tunnel (2).

8. The method for constructing an abutment in a tunnel excavation method according to any one of claims 1 to 7, characterized in that: The upper area of ​​the arch foundation includes a base portion (9) close to the mountain, and also includes an installation portion (11) close to the river center. The installation portion (11) is used to connect the arch positioning frame (12). In step S7, the base portion (9) of the upper area of ​​the arch foundation is first cast.

9. The tunnel excavation method according to claim 8, characterized in that: During the pouring process of the base portion (9), a second interface connecting steel bar (10) is arranged on the side of the base portion (9) close to the river center.

10. The method for constructing an abutment in a tunnel excavation method according to claim 8, characterized in that: In step S7, after the concrete of the base part (9) is formed, the base part (9) is excavated to the end of the base part (9) close to the river center, and then the installation part (11) is poured.

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