An underwater foundation pit retaining structure system and construction method based on traction pipe technology

Abstract

The present invention discloses an underwater foundation pit retaining structure system and construction method based on traction pipe technology, which is characterized in that: it includes a traction pipe retaining wall enclosure located at the boundary of the underwater foundation pit, the traction pipe retaining wall enclosures on both sides are connected by underwater zero-weight lateral pressure support, and anti-slip supports for the slope are provided at both ends of the traction pipe retaining wall enclosure for retaining soil; the traction pipe retaining wall enclosure includes traction pipes stacked from bottom to top, the traction pipes include a main pipeline located in the center and grouting flower pipes arranged circumferentially around the main pipeline, the grouting flower pipes are outer-circumferentially provided with a base, the main pipeline is outer-circumferentially provided with a clamp, the clamp is connected to the base through a connecting plate, and the connecting plate is hinged to the clamp and the base respectively.

Description

Technical Field

[0001] The present invention relates to an underwater foundation pit retaining structure system and a construction method based on traction tube technology, and belongs to the fields of underwater concrete replacement of shield engineering, underwater bottom plate engineering of hydraulic structures, etc. Background Art

[0002] River crossings can be accomplished by tunnels or bridges. To address land use and urban planning issues, more and more underground tunnels are being constructed across rivers and streams in cities. Due to topographical factors, lead line lengths, and investment decisions, a large number of shallow river tunnel projects face challenges. The key challenges are anti-floating and anti-seepage safety during construction and operation, as well as the feasibility of the construction plan. Currently available technologies involve diverting temporary river channels near tunnel lines to ensure smooth flow, while also implementing dryland construction protection measures or backfilling to address existing problems. During tunnel shield boring, the depth of the silt layer can cause the shield machine to sink and the tunnel to float. This can be addressed through the comprehensive use of high-pressure jet grouting to reinforce the foundation under dryland conditions. The method of excavating temporary river channels for diversion requires a large amount of engineering work and requires increasing the land space to accommodate the setting up of temporary river channels. For example, 201910978416.3 Construction method of earth pressure shield crossing river channel in water bag pebble mixed soil layer and 201910780497.6 A construction process of tunnel under the river both use the method of excavating temporary river channels and have a long construction period, which has affected the progress of the project construction to a certain extent.

[0003] Common methods for reinforcing soft soils, such as silt, include high-pressure jet grouting, pressure grouting, and in-situ cement mixing. However, these methods are difficult to implement in shallow buried areas without sufficient cover and underwater. The underwater sludge suction and replacement process addresses the challenges of deep underwater foundation pits. On the one hand, it addresses slope stability and minimizes excavation workload; on the other, it addresses the stability of riverbank slopes and surrounding buildings. The stability of foundation pits with weak layers is particularly complex.

[0004] Patent No. 202110961945.X describes a method for constructing a tunnel excavation through a non-navigable river. This method utilizes both river channel backfill and excavation backfill. This method is applicable only to rivers that can be shut off and de-navigated. It cannot address the instability of shallow burials in muddy riverbeds. Backfilling only provides a temporary anti-floating solution during construction, not a permanent solution after excavation. Therefore, it only provides a temporary solution, resulting in a high workload and significant impact on the river. Summary of the Invention

[0005] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides an underwater foundation pit retaining structure system and construction method based on traction tube technology. The traction tube support structure can be used not only as a support system, but also as a top plate construction for the replacement area, truly playing the role of underwater peripheral support and top surface covering, reducing workload, improving work efficiency, reducing risks, and reducing the impact of flood discharge and flood prevention during the flood season.

[0006] Technical solution: In order to solve the above technical problems, the present invention provides an underwater foundation pit retaining structure system and construction method system based on traction pipe technology, including a traction pipe retaining wall enclosure located at the boundary of the underwater foundation pit, and the traction pipe retaining wall enclosures on both sides are connected by underwater zero-weight lateral pressure support, and anti-slip supports for the slope are provided at both ends of the traction pipe retaining wall enclosure for retaining soil; the traction pipe retaining wall enclosure includes traction pipes stacked from bottom to top, and the traction pipes include a main pipeline located in the center and a grouting flower pipe arranged circumferentially around the main pipeline, the grouting flower pipe is outer-circumferentially provided with a base, the main pipeline is outer-circumferentially provided with a clamp, the clamp is connected to the base through a connecting plate, and the connecting plate is hinged to the clamp and the base respectively.

[0007] The above-mentioned construction method of an underwater foundation pit retaining structure system based on the traction pipe technology comprises the following steps:

[0008] (1) Steel pipe piles for retaining soil are driven into the river bank on both sides of the river channel in the underwater foundation pit area. The steel pipe piles are arranged in double rows and concrete is poured into the double rows of steel pipe piles to form anti-slip support for the bank slope;

[0009] (2) According to the traction pipe process, first use a drilling rig to drill a pilot hole according to the designed route, then pull back to expand the hole diameter to a diameter that meets the requirements for laying the traction main pipe and grouting flower pipe, fix the main pipe and grouting flower pipe to the traction head, and pull the pipe back; the main pipe is connected by hot melt process, the grouting flower pipe is connected by threaded sleeve, and the main pipe and steel flower pipe are connected by clamps and hinges;

[0010] (3) After pulling back and traction into place, remove the traction equipment, ensure that the main pipeline does not move, pull and stretch the steel flower pipe, rotate the connecting hinge, and expand the grouting flower pipe;

[0011] (4) Repeat steps (2) and (3) until all main pipes and grouting flower pipes are laid out;

[0012] (5) Underwater non-dispersible self-leveling concrete is poured inside the main pipeline, and pressure-injected cement-based slurry is used to fill the surrounding soil in the grouting flower pipe. Multiple traction pipe systems are integrated to play a role in soil retaining and protection; the main pipeline, flower pipe (high-strength steel wire in the flower pipe) and the surrounding reinforced soil form a structural support;

[0013] (5) The underwater mud suction, excavation-support-bottom protection process is adopted in sections, layers and phases. An underwater zero-weight horizontal water pressure support is set between the main pipelines on both sides to realize the closed-loop process of excavation-support-cushion-pouring, and complete the underwater foundation pit excavation, support and concrete pouring.

[0014] Preferably, in step (4), after all main pipelines are laid out, they are in a U or V shape.

[0015] Beneficial effects: The underwater foundation pit retaining structure system and construction method based on the traction pipe technology of the present invention uses a combination of trenchless traction pipe laying technology and flower pipe grouting technology to solve the problem of underwater foundation pit support. Underwater foundation pit enclosure generally requires the installation of a pier or ship in the river channel for sheet pile construction; without affecting flood discharge and ship passage, the support body cannot be exposed to the water surface, which increases a large number of underwater cutting and docking problems. The traction pipe support structure can be used not only as a support system, but also as a top plate construction for the replacement area, which truly plays the role of underwater peripheral support and top surface covering, reducing workload, improving work efficiency, reducing risks, and reducing the impact of flood discharge and flood prevention during the flood season. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the main structure of the present invention.

[0017] Figure 2 It is a schematic diagram of the top structure of the present invention.

[0018] Figure 3 This is a schematic diagram of the state where the grouting flower tube has not been expanded.

[0019] Figure 4 This is a schematic diagram of the state of the grouting flower tube being expanded.

[0020] Figure 5 Schematic diagram of the vertical arrangement of traction tubes.

[0021] Figure 6 Schematic diagram of the inclined arrangement of traction pipe intrusion. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings.

[0023] like Figure 1As shown, the present invention provides an underwater foundation pit retaining structure system and construction method system based on traction pipe technology, including a traction pipe retaining wall enclosure located at the boundary of the underwater foundation pit, and the traction pipe retaining wall enclosures on both sides are connected by underwater 0 deadweight lateral pressure supports 7, and the pressure can be hydraulic, air, water or oil pressure, and anti-slip supports 8 for retaining soil are provided at both ends of the traction pipe retaining wall enclosure; the traction pipe retaining wall enclosure includes traction pipes stacked from bottom to top, and the traction pipes include a main pipeline 1 located in the center and a grouting flower pipe 9 arranged circumferentially around the main pipeline 1, the grouting flower pipe 9 is covered with a base, and the main pipeline 1 is covered with a clamp 11, and the clamp 11 is connected to the base 12 through a connecting plate 13, and the connecting plate 13 is hinged to the clamp 11 and the base 12 respectively.

[0024] The above-mentioned construction method of an underwater foundation pit retaining structure system based on the traction pipe technology comprises the following steps:

[0025] (1) Steel pipe piles 3 for retaining soil are driven into the river bank on both sides of the river channel in the underwater foundation pit area. The steel pipe piles 3 are arranged in double rows and connected by plates 2. Concrete is poured into the double rows of steel pipe piles to form a bank slope anti-sliding support 8, as shown in FIG. Figure 1 and Figure 2 As shown;

[0026] (2) According to the traction pipe process, first use a drilling rig to drill a pilot hole according to the designed route, then pull back to expand the hole diameter to a diameter that meets the requirements of laying the traction main pipe 1 and the grouting flower pipe 9, fix the main pipe 1 and the grouting flower pipe 9 to the traction head, and pull the pipe back; the main pipe 1 is connected by hot melt process, and the grouting flower pipe 9 is connected by threaded sleeve. The main pipe 1 and the steel flower pipe 9 are connected by clamps 11 and hinges. The initial state of the connecting plate 13 is tilted, such as Figure 3 As shown;

[0027] (3) After pulling back to the right position, remove the pulling equipment, ensure that the main pipeline 1 does not move, pull and stretch the steel flower pipe 9, rotate the connecting hinge, and expand the grouting flower pipe 9. Figure 4 As shown;

[0028] (4) Repeat steps (2) and (3) until all main pipes 1 and grouting flower pipes 9 are laid out. After all main pipes 1 are laid out, they are in a V shape, as shown in the following example: Figure 6 As shown, or arranged vertically, as Figure 5 As shown;

[0029] (5) Underwater non-dispersible self-leveling concrete is poured into the main pipeline 1, and the grouting flower pipe 9 is filled with pressure-injected cement-based slurry to fill the surrounding soil. Multiple traction pipe systems are integrated to play a role in soil retaining protection; the main pipeline 1, grouting flower pipe 9 (high-strength steel wire in the grouting flower pipe 9) and the surrounding reinforced soil constitute structural support;

[0030] (5) The underwater mud suction, excavation-support and bottom protection process is adopted in sections, layers and phases. Underwater 0 deadweight horizontal water pressure support 7 is set between the main pipelines 1 on both sides to realize the closed loop process of excavation-support-cushion-pouring. The underwater foundation pit excavation and support 8 and concrete 5 pouring are completed. Grouting pipes are pre-buried at a certain interval at the bottom of the cushion layer. When the concrete reaches above 0.5MPa and below 2.0MPa, grouting reinforcement is carried out.

[0031] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An underwater foundation pit retaining structure system based on traction pipe technology, characterized by: It includes a traction pipe retaining wall enclosure located at the boundary of an underwater foundation pit, the traction pipe retaining wall enclosures on both sides are connected by underwater zero-weight lateral pressure support, and anti-slip supports for the slope are provided at both ends of the traction pipe retaining wall enclosure for retaining soil; the traction pipe retaining wall enclosure includes traction pipes stacked from bottom to top, the traction pipes include a main pipeline located in the center and grouting flower pipes arranged circumferentially around the main pipeline, the grouting flower pipes are outer-coated with a base, the main pipeline is outer-coated with a clamp, the clamp is connected to the base through a connecting plate, and the connecting plate is hinged to the clamp and the base respectively.

2. A construction method of an underwater foundation pit retaining structure system based on traction pipe technology according to claim 1, characterized in that: The following steps are involved: (1) Steel pipe piles for retaining soil are driven into the river bank on both sides of the river channel in the underwater foundation pit area. The steel pipe piles are arranged in double rows and concrete is poured into the double rows of steel pipe piles to form anti-slip support for the bank slope; (2) According to the traction pipe process, first use a drilling rig to drill a pilot hole according to the designed route, then pull back to expand the hole diameter to a diameter that meets the requirements for laying the traction main pipe and grouting flower pipe, fix the main pipe and grouting flower pipe to the traction head, and pull the pipe back; the main pipe is connected by hot melt process, the grouting flower pipe is connected by threaded sleeve, and the main pipe and steel flower pipe are connected by clamps and hinges; (3) After pulling back and traction into place, remove the traction equipment, ensure that the main pipeline does not move, pull and stretch the steel flower pipe, rotate the connecting hinge, and expand the grouting flower pipe; (4) Repeat steps (2) and (3) until all main pipes and grouting pipes are laid out; (5) Underwater non-dispersible self-leveling concrete is poured inside the main pipeline, and pressure-injected cement-based slurry is used to fill the surrounding soil in the grouting flower pipe. Multiple traction pipe systems are integrated to play a role in soil retaining and protection; the main pipeline, flower pipe (high-strength steel wire in the flower pipe) and the surrounding reinforced soil form a structural support; (5) The underwater mud suction, excavation-support-bottom protection process is adopted in sections, layers and phases. An underwater zero-weight horizontal water pressure support is set between the main pipelines on both sides to realize the closed-loop process of excavation-support-cushion-pouring, and complete the underwater foundation pit excavation, support and concrete pouring.

3. The construction method of the underwater foundation pit retaining structure system based on the traction pipe technology according to claim 2 is characterized by: In step (4), after all the main pipelines are laid out, they are arranged in a U or V shape according to the stability of the soil.

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