Underground super-wide underpass construction method

Abstract

The application discloses a kind of underground super-wide underpass construction methods, comprising the following steps: S1, the field of underpass position surface is excavated and constructed, and a row of outside steel sheet piles and a row of inside steel sheet piles are respectively set up;S2, after excavation to channel design bottom elevation, foundation treatment is carried out, and non-mixed road side box and half U groove side wall are formed by pouring at the rear end and the front end of underpass;S3, the earthwork of main lane is excavated to channel design bottom elevation;S4, mobile formwork trolley is introduced to main lane, and pouring construction frame structure is carried out, which and non-mixed road side box jointly form the overall structure of underpass, and underpass bottom is poured at the bottom of main lane, which and half U groove side wall jointly form the overall U groove of underpass.The construction method of the application combines permanent structure of non-mixed road side box and temporary structure of formwork mobile trolley and implants assembly technology into engineering construction to realize green and rapid construction of super-wide underground passage.

Description

Technical Field

[0001] This invention relates to the field of efficient construction of ultra-wide underground underpasses. More specifically, this invention relates to a construction method for ultra-wide underground underpasses. Background Technology

[0002] With societal development, urban landscape elements have become more mature and rational. Compared to overpasses, underpasses, with their simple and aesthetically pleasing overall effect and lower investment, are increasingly favored by urban designers. Common underpass designs feature a U-shaped open-cut trench + buried frame box culvert structure, typically including two-way main lanes, mixed-traffic lanes on both sides, and pedestrian walkways. Construction of the underpass structure inevitably involves ultra-wide and deep foundation pit work. Currently, common underpass foundation pit support structures include diaphragm wall support (with long supports installed in opposite directions) and ultra-high-strength cast-in-place pile support (in conjunction with a water-stop curtain and long support structures in opposite directions). The underpass frame culvert is formed by multiple pours using a full-span scaffolding method.

[0003] Conventional support methods for underpasses, such as diaphragm walls and cast-in-place piles, are costly, difficult to dismantle, and have long construction periods. The full-span scaffolding method for frame structures requires multiple pours, resulting in low efficiency in scaffolding erection and dismantling, increased construction joints, and a high risk of water seepage at the joints later on.

[0004] Compared to the support methods for ultra-wide and deep foundation pits of underpasses, researchers proposed a structure using steel sheet pile cofferdams and inclined bracing. The foundation pit employs a pre-reserved core soil excavation technique, which reduces the cost of the support structure to some extent and further improves construction efficiency. They also proposed using high-strength, easy-to-install disc-lock scaffolding instead of coupler-type or cup-lock scaffolding for the tunnel roof support, which also improves construction efficiency and ensures the safety of the formwork and support system.

[0005] The above measures still do not solve the problems of high safety risks and long construction periods in ultra-wide foundation pit construction. The foundation pit excavation needs to be carried out in sections, and there is a risk of collapse during the rainy season. The bottom slab of the underpass frame needs to be poured in stages according to the diagonal bracing construction, resulting in numerous construction joints and poor structural integrity. The diagonal bracing in the foundation pit support structure requires multiple system conversions according to the earthwork excavation and bottom slab construction procedures, which has a significant impact on structural stability and increases unpredictable risks. The installation and dismantling of the modular scaffolding requires a large amount of labor, and elevation adjustments are time-consuming and labor-intensive, and it cannot be guaranteed that the entire passage can be poured in one go, making it difficult to meet the increasingly fast-paced construction demands of engineering projects. Summary of the Invention

[0006] To achieve these objectives and other advantages according to the present invention, a preferred embodiment of the present invention provides an efficient construction method for an underground ultra-wide underpass, comprising the following steps: S1. Excavate the site slab at the location of the underpass. After the site slab is excavated to the relevant elevation, level the site. Drive one row of outer steel sheet piles and one row of inner steel sheet piles between the outer side walls of the underpass and the side walls of the mixed traffic area. The two rows of inner steel sheet piles are located between the two rows of outer steel sheet piles. The side box pit is located between the row of outer steel sheet piles and the row of inner steel sheet piles on the same side of the underpass. S2. The earthwork of the two side box foundation pits on both sides of the underpass is excavated in layers. After excavation to the design bottom elevation of the passage, the foundation is treated. The underpass includes a U-shaped trough section on the front side and a frame section on the rear side. The side box of the pedestrian and non-motorized vehicle lane is formed by pouring with the help of a mobile formwork trolley on the front side of the two side box foundation pits. The semi-U-shaped trough side wall is formed by pouring with the help of the two side box foundation pits on the rear side. S3. Remove the inner steel sheet piles, use the existing side boxes of the pedestrian and non-motorized vehicle lane and the side walls of the semi-U-shaped channel as the foundation pit support structure, and excavate the earthwork of the main lane located between the two side box foundation pits to the design bottom elevation of the channel. S4. The main lane is located between the two side box pits. A mobile formwork trolley is introduced to the front of the main lane corresponding to the side box of the pedestrian and non-motorized vehicle lane, and the frame structure is poured. Together with the side box of the pedestrian and non-motorized vehicle lane, it forms the overall structure of the underpass. The bottom of the underpass is poured at the rear of the main lane corresponding to the side wall of the semi-U-shaped channel. Together with the side wall of the semi-U-shaped channel, it forms the overall U-shaped channel of the underpass.

[0007] According to another technical solution of the present invention, in step S2, the soil in the two side box foundation pits located on both sides of the underpass is excavated in layers, and steel sheet pile walers can be set according to the geological conditions.

[0008] According to another technical solution of the present invention, in step S2, the side boxes for pedestrian and non-pedestrian mixed traffic lanes are formed by casting on the front side of the two side box foundation pits using a mobile template trolley, specifically including the following operations: The foundation layer and bottom slab of the side box are poured on the front side of the two side box foundation pits, the side wall reinforcement is tied, the mobile formwork trolley is moved in as the inner side formwork and bottom formwork of the top slab, the top slab reinforcement is tied, and the side walls and top slab are poured in one go to form the side box structure of the pedestrian and non-motorized vehicle mixed traffic lane.

[0009] According to another technical solution of the present invention, in step S2, the semi-U-shaped sidewalls are formed by casting on the rear side of the two side box foundation pits, specifically including the following operations: A fixed steel mold was installed on the rear side of the two side box pits, and the bottom plate and side walls were poured to finally form the side walls of the semi-U-shaped channel.

[0010] According to another technical solution of the present invention, after S4, the method further includes: S5. After the concrete strength of the main lane meets the requirements, remove the mobile formwork trolley, remove the outer steel sheet piles, and carry out the waterproofing and ancillary facility construction of the passage.

[0011] According to another technical solution of the present invention, in step S3, before the earthwork excavation of the main lane located between the two side box pits is carried out to the designed bottom elevation of the channel, the following operations are also required: After the concrete strength of the side box of the pedestrian and non-motorized vehicle lane and the side wall of the semi-U-shaped channel meets the requirements, the moving formwork trolley is removed, and plain concrete is filled into the gap between the side box of the pedestrian and non-motorized vehicle lane and the outer steel sheet pile. After the strength of the plain concrete meets the requirements, the inner steel sheet pile is removed. At this time, the side box of the pedestrian and non-motorized vehicle lane and the side wall of the semi-U-shaped channel form a support.

[0012] The present invention has at least the following beneficial effects: This invention provides an efficient construction method for ultra-wide underground underpasses. The process is clear, requires minimal resources, and helps to further reduce project costs, shorten the construction period, improve the construction quality of cast-in-place concrete structures, reduce labor intensity, and ensure operational safety. It points the way for industrialized construction in urban development and has significant socio-economic benefits.

[0013] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0014] Figure 1 This is a construction diagram of step S1 in the present invention; Figure 2 This is a construction diagram of the frame segment in step S2 of the present invention; Figure 3 This is a construction diagram of the U-shaped trough section in step S2 of the present invention; Figure 4 This is a construction diagram of the frame segment in step S3 of the present invention; Figure 5 This is a construction diagram of the U-shaped trough section in step S3 of the present invention; Figure 6 This is a construction diagram of the frame segment in step S4 of the present invention; Figure 7 This is a schematic diagram showing the completion of the frame segment construction in step S5 of the present invention; Figure 8 This is a schematic diagram showing the completion of the construction of the U-shaped trough section in step S5 of this invention. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0016] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious modifications will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0017] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0018] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0019] like Figure 1-8 As shown, a preferred embodiment of the present invention provides a method for constructing an underground ultra-wide underpass, characterized by comprising the following steps: S1, such as Figure 1 As shown, the excavation of the site 1 on the surface of the underpass location is carried out. After the site 1 is excavated to the relevant elevation, the site is leveled. A row of outer steel sheet piles 2 and a row of inner steel sheet piles 3 are respectively driven between the outer side walls of the underpass and the side walls of the mixed traffic area. The two rows of inner steel sheet piles 3 are located between the two rows of outer steel sheet piles 2. The side box pit is located between the row of outer steel sheet piles 2 and the row of inner steel sheet piles 3 on the same side of the underpass. S2. The earthwork for the two side box foundation pits located on both sides of the underpass will be excavated in layers. After excavation to the designed bottom elevation of the underpass, foundation treatment will be carried out. The underpass includes a U-shaped trench section at the front and a frame section at the rear. Figure 2 As shown, the side boxes 5 of the pedestrian and non-motorized vehicle lanes are formed by pouring concrete on the front side of the two side box foundation pits using a mobile formwork trolley 4. Figure 3 As shown, a semi-U-shaped sidewall 6 is formed by pouring concrete on the rear side of the two side box foundation pits; S3, such as Figure 4-5As shown, the inner steel sheet piles are removed, and the existing pedestrian and non-motorized vehicle side boxes and semi-U-shaped side walls are used as the foundation pit support structure. This allows the permanent structure to replace the temporary foundation pit support structure, thereby saving materials and construction time. Then, the earthwork of the main lane located between the two side box foundation pits is excavated to the design bottom elevation of the passage. S4, such as Figure 6-8 As shown, the main lane is located between the two side box pits. A movable formwork trolley 4 is introduced to the front of the main lane corresponding to the side box 5 of the pedestrian and non-motorized vehicle lane, and the frame structure is poured. Together with the side box 5 of the pedestrian and non-motorized vehicle lane, it forms the overall structure 8 of the underpass. The bottom of the underpass is poured at the rear of the main lane corresponding to the side wall 6 of the semi-U-shaped channel. Together with the side wall 6 of the semi-U-shaped channel, it forms the overall U-shaped channel 9 of the underpass.

[0020] S5. After the concrete strength of the main lane meets the requirements, remove the mobile formwork trolley 4, remove the outer steel sheet pile 2, and carry out the waterproofing and ancillary facility construction of the passage.

[0021] The proposed efficient construction method for ultra-wide underground underpasses in the above technical solutions can effectively utilize the permanent structure of the side box 5 of the mixed pedestrian and non-motorized vehicle lane as the support structure on both sides of the foundation pit, reducing the material input of super-strong support, water-stop curtain and internal support for the foundation pit, ensuring economy while significantly improving the safety of foundation pit construction; referring to the idea of ​​tunnel construction lining trolley, the construction process introduces a freely movable, integral and quick-installation and dismantling formwork moving trolley structure to replace the full-span scaffolding method, ensuring that the frame side walls and top slab can be poured at one time, improving construction efficiency, reducing the input of construction joint waterstop, reducing the risk of structural seepage, and ensuring the good integrity and safety of the underground structure.

[0022] This invention introduces an integrated movable template support system, which combines the permanent structure of the side box 5 of the mixed pedestrian and non-motorized vehicle lane with the temporary structure of the template moving trolley and incorporates prefabricated technology into the engineering construction to achieve green and rapid construction of ultra-wide underground passages, realize the inherent safety of the project, and improve the efficiency of engineering construction while ensuring product quality.

[0023] In another technical solution, in S2, the soil of the two side box foundation pits on both sides of the underpass is excavated in layers. Steel sheet pile walers can be set according to the geological conditions. If the soil is relatively soft, steel sheet piles need to be driven into the vicinity of the excavation during the excavation process to avoid collapse during the excavation process.

[0024] In another technical solution, in step S2, the side box 5 for pedestrian and non-motorized lanes is formed by casting concrete in one of the side box foundation pits, specifically including the following operations: In one of the side box foundation pits, the foundation layer and the bottom plate of the side box are poured, the side wall reinforcement is tied, the mobile formwork trolley 4 is moved in as the inner side formwork and the bottom formwork of the top plate, the top plate reinforcement is tied, and the side wall and top plate are poured in one go to form the side box structure 5 of the pedestrian and non-motorized vehicle mixed lane. In another technical solution, in step S2, a semi-U-shaped sidewall 6 is formed by casting concrete in another side box foundation pit, specifically including the following operations: Install a prefabricated steel mold in another side box pit, and pour the bottom plate and side walls to finally form a semi-U-shaped side wall 6.

[0025] In another technical solution, before excavating the earthwork of the main lane located between the two side box pits to the designed bottom elevation of the passage in step S3, the following operations are required: After the concrete strength of the pedestrian and non-motorized vehicle side box 5 and the semi-U-shaped trough side wall 6 meets the requirements, the movable formwork trolley 4 is removed, and plain concrete 7 is filled into the gap between the pedestrian and non-motorized vehicle side box 5 and the outer steel sheet pile 2. After the strength of the plain concrete 7 meets the requirements, the inner steel sheet pile 3 is removed. At this time, the pedestrian and non-motorized vehicle side box 5 and the semi-U-shaped trough side wall 6 that have been constructed will serve as the foundation pit support. The permanent structure is used to replace the temporary foundation pit support structure, thereby saving materials and construction time.

[0026] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A construction method for an ultra-wide underground underpass, characterized in that, Includes the following steps: S1. Excavate the site slab at the location of the underpass. After the site slab is excavated to the design elevation, level the site. Drive a row of outer steel sheet piles and a row of inner steel sheet piles between the outer side walls of the underpass and the side walls of the mixed traffic area. The two rows of inner steel sheet piles are located between the two rows of outer steel sheet piles. The side box pit is located between the row of outer steel sheet piles and the row of inner steel sheet piles on the same side of the underpass. S2. The earthwork of the two side box foundation pits on both sides of the underpass is excavated in layers. After excavation to the design bottom elevation of the passage, the foundation is treated. The underpass includes a U-shaped trough section on the rear side and a frame section on the front side. The side box of the pedestrian and non-motorized vehicle lane is formed by pouring with the help of a mobile formwork trolley on the front side of the two side box foundation pits. The semi-U-shaped trough side wall is formed by pouring with the help of the two side box foundation pits on the rear side. S3. Remove the inner steel sheet piles, use the existing side boxes of the pedestrian and non-motorized vehicle lane and the side walls of the semi-U-shaped channel as the foundation pit support structure, and excavate the earthwork of the main lane located between the two side box foundation pits to the design bottom elevation of the channel. S4. The main lane is located between the two side box pits. A mobile formwork trolley is introduced to the front of the main lane corresponding to the side box of the pedestrian and non-motorized vehicle lane, and the frame structure is poured. Together with the side box of the pedestrian and non-motorized vehicle lane, it forms the overall structure of the underpass. The bottom of the underpass is poured at the rear of the main lane corresponding to the side wall of the semi-U-shaped channel. Together with the side wall of the semi-U-shaped channel, it forms the overall U-shaped channel of the underpass.

2. The construction method for the underground ultra-wide underpass according to claim 1, characterized in that, In S2, the earthwork of the two side box foundation pits located on both sides of the underpass is excavated in layers, and steel sheet pile walers are set according to the geological conditions.

3. The construction method for the ultra-wide underground underpass according to claim 1, characterized in that, In step S2, the side boxes for pedestrian and non-motorized vehicle mixed-use lanes are formed by casting on the front side of the two side box foundation pits using a mobile formwork trolley. This specifically includes the following operations: A foundation layer and bottom slab of the side box are poured on the front side of the two side box foundation pits. The side wall reinforcement is tied. A mobile formwork trolley is moved in as the inner side formwork and bottom formwork of the top slab. The top slab reinforcement is tied. The side walls and top slab are poured in one go to form the side box structure of the pedestrian and non-motorized vehicle mixed-use road.

4. The construction method for the underground ultra-wide underpass according to claim 1, characterized in that, In step S2, the semi-U-shaped sidewalls are formed by pouring concrete on the rear side of the two side box foundation pits, specifically including the following operations: A fixed steel mold was installed on the rear side of the two side box pits, and the bottom plate and side walls were poured to finally form the side walls of the semi-U-shaped channel.

5. The construction method for the ultra-wide underground underpass according to claim 1, characterized in that, Following S4, the following also includes: S5. After the concrete strength of the main lane meets the requirements, remove the mobile formwork trolley, remove the outer steel sheet piles, and carry out the waterproofing and ancillary facility construction of the passage.

6. The construction method for the ultra-wide underground underpass according to claim 1, characterized in that, In step S3, before excavating the earthwork of the main lane located between the two side box pits to the designed bottom elevation of the passage, the following operations are required: After the concrete strength of the side box of the pedestrian and non-motorized vehicle lane and the side wall of the semi-U-shaped channel meets the requirements, the moving formwork trolley is removed, and plain concrete is filled into the gap between the side box of the pedestrian and non-motorized vehicle lane and the outer steel sheet pile. After the plain concrete strength meets the requirements, the inner steel sheet pile is removed. At this time, the side box of the pedestrian and non-motorized vehicle lane and the side wall of the semi-U-shaped channel form a support.

Images