A construction method for excavating a communication channel in a water-rich sand layer

Abstract

The invention provides a water-rich sand layer communication channel excavation construction method, which belongs to the technical field of underground channel construction, and specifically comprises the following steps: step S1, determining the position of the communication channel; step S2, drilling and grouting at the determined position, and reinforcing the construction area of ​​the communication channel; step S3, determining the position of a horizontal vacuum dewatering hole in one of the tunnels at both ends of the communication channel; step S4, arranging vacuum dewatering equipment at the position of the vacuum dewatering hole; step S5, removing groundwater outside the communication channel by the vacuum dewatering equipment to ensure excavation safety; step S6, starting to excavate the communication channel for a set distance after dewatering is completed; step S7, repeating steps S2-S6 until excavation is completed, so as to solve the technical problem that the existing construction method is inconvenient to directly dewater on the ground.

Description

Technical Field

[0001] The invention belongs to the technical field of underground channel construction, and in particular relates to a water-rich sand layer communication channel excavation construction method. Background Art

[0002] Urban development has intensified urban traffic pressure. In order to ease the traffic pressure, many cities are taking measures. However, due to the limitations of urban size and land area, many cities have found it difficult to develop ground transportation on a large scale. Therefore, more and more cities have begun to build subway projects.

[0003] Some construction areas may encounter water-rich sand layers during construction. Water-rich sand layers are a special geological structure composed of soil particles and water resources. The flow pattern of water in water-rich sand layers is relatively complex, and the spatial structure of soil particles in water-rich sand layers is numerous and has different forms. When excavating tunnels such as subways or communication passages in this area, the rock layer is very likely to deform into a flow-plastic state, resulting in sand gushing and landslides during construction. In the worst case, the initial support of the tunnel will be deformed, endangering construction safety, and in the worst case, the tunnel will collapse, causing safety accidents.

[0004] In order to avoid the influence of water-rich sand layer on the construction of connecting passages between subways, the commonly used method is to first conduct underground dewatering. The common dewatering method is well point dewatering. However, since subway shield construction is mostly carried out in busy areas, the connecting passages are located under busy roads and the upper surface pipelines are dense, which makes it inconvenient to directly arrange construction machinery and dewatering well points over a large area.

[0005] Therefore, it is necessary to provide an improved technical solution to address the above-mentioned deficiencies in the prior art. Summary of the invention

[0006] The purpose of the present invention is to provide a construction method for excavating a communication channel in a water-rich sand layer, so as to solve the technical problem that the existing construction method is inconvenient for direct precipitation on the ground.

[0007] In order to achieve the above-mentioned purpose, the water-rich sand layer communication channel excavation construction method of the present invention provides the following technical solutions:

[0008] A construction method for excavating a communication channel in a water-rich sand layer comprises the following steps:

[0009] Step S1, determining the location of the communication channel;

[0010] Step S2, drilling and grouting at the determined location to reinforce the construction area of ​​the communication channel;

[0011] Step S3, determining the position of a horizontal vacuum drainage hole in one of the tunnels at both ends of the communication channel;

[0012] Step S4, arranging vacuum dewatering equipment at the vacuum dewatering hole position;

[0013] Step S5, draining the groundwater outside the communication channel by vacuum dewatering equipment to ensure excavation safety;

[0014] Step S6, after the precipitation is completed, start excavating the communication channel to set the distance;

[0015] Step S7, repeat steps S2-S6 until the excavation is completed.

[0016] As a further optimized technical solution, in step S4, the vacuum dewatering equipment includes a vacuum dewatering pipe, a main water collecting pipe and a vacuum pump. The vacuum dewatering pipes are arranged at intervals around the outer side of the connecting channel. Each vacuum dewatering pipe is connected to the main water collecting pipe through a quick-connect flange structure, and the main water collecting pipe is connected to the vacuum pump.

[0017] As a further optimized technical solution, the quick connection flange structure includes a first flange and a second flange, the first flange is arranged on one of the pipe bodies of the vacuum downcomer or the main water collecting pipe, and the second flange is arranged on the other pipe body;

[0018] A plurality of connection blocks are arranged circumferentially at intervals on the end surface of the first flange away from the pipe body connected thereto, the connection block having a connection rod and a positioning block which are integrally connected and have different radial sizes, the diameter of the connection rod is smaller than the diameter of the positioning block, and one end of the connection rod away from the positioning block is fixedly connected to the first flange;

[0019] The second flange has a connecting groove and a limiting structure. The connecting groove is used to place a positioning block. The limiting structure is used to be clamped on the connecting rod and press the positioning block to achieve the connection between the first flange and the second flange.

[0020] As a further optimized technical solution, an annular groove is arranged on the end face of the second flange facing the first flange, the connecting groove is arranged at the bottom of the annular groove, and each position close to the connecting groove in the annular groove is provided with a limiting structure, and a driving structure is connected between the limiting structures to drive the limiting structures to slide along the annular groove.

[0021] As a further optimized technical solution, the limiting structure is an arc block structure adapted to the annular slide groove, and the limiting structure has an arc groove with an opening at one end, the opening of the arc groove faces the adjacent connecting groove, and the width of the arc groove is not less than the radial dimension of the connecting rod and less than the radial dimension of the positioning block.

[0022] As a further optimized technical solution, the limiting structure is provided with two groups, and the two groups of limiting structures are symmetrically arranged in the annular slide groove;

[0023] The driving structure includes an elastic connecting member, a rope-like traction member and a driving unit. The rope-like traction member is arranged in each group of limiting structures and is connected to a limiting structure at both ends. The two ends of the elastic connecting member are respectively connected to one end of a group of limiting structures. The other ends of the two groups of limiting structures are connected to the driving unit through the rope-like traction member. The driving unit pulls the two groups of limiting structures to slide along the annular slide groove through the rope-like traction member.

[0024] As a further optimized technical solution, the driving unit includes a screw, one end of which passes through the side wall of the second flange and extends into the annular groove. The screw is threadedly connected to the second flange, and one end of the screw that passes through the annular groove is respectively fixedly connected to the rope-like traction members on both sides. When the screw is rotated, the rope-like traction members on both sides are wrapped around or detached from the screw.

[0025] As a further optimized technical solution, a protective tube is sleeved on the outer side of one end of the screw extending into the annular slide groove, one end of the protective tube is fixedly connected to the annular slide groove, and the other end is rotatably cooperated with the screw, and the connection position of the rope-like traction piece and the screw is inside the protective tube.

[0026] As a further optimized technical solution, the quick-connect flange structure also includes a pre-tightening gasket, which has a perforation corresponding to the positioning block. A clamping block is provided on the side of each perforation facing the second flange. When connecting the first flange and the second flange, the limiting structure slides and cooperates with the clamping block to stably connect the first flange to the second flange.

[0027] As a further optimized technical solution, the top surface of the limiting structure is inclined and tilted upward from the end adjacent to the connecting groove to the end away from the connecting groove. The clamping block is inclined toward one side of the second flange, and the inclination direction is opposite to the limiting structure.

[0028] Beneficial effects: By using the construction method of the present invention, precipitation is transferred from the ground to the cave for construction, and there is no need to build precipitation wells on the ground, which does not occupy surface space and has little impact on the construction area; in addition, the water pumped out by vacuum precipitation is clean water, pollution-free and can be directly discharged, which meets the requirements of green construction specifications and has good environmental benefits. In addition, grouting reinforcement is carried out before construction to change the physical properties of the original soil, increase the density of the soil, and improve its compressive strength, thereby further reducing the risk of ground subsidence during the construction of the communication channel and ensuring the safety of ground buildings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0030] Figure 1A schematic diagram of a construction process of an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of grouting construction according to an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of the arrangement of vacuum dewatering holes according to an embodiment of the present invention;

[0033] Figure 4 A schematic diagram of the structure of a vacuum precipitation device according to an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the structure of a quick-connect flange according to an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the first flange structure of an embodiment of the present invention;

[0036] Figure 7 It is a schematic diagram of assembling the second flange and the pre-tightening gasket according to an embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of the second flange structure of an embodiment of the present invention;

[0038] Fig. 9 The figure is a schematic diagram of the working state of the quick connection flange structure according to an embodiment of the present invention.

[0039] In the figure: 1. communication channel; 2. vacuum dewatering hole; 3. tunnel; 301. grouting drilling direction; 4. vacuum dewatering pipe; 5. main water collecting pipe; 6. vacuum pump; 7. quick connection flange structure; 701. first flange; 7011. connecting rod; 7012. positioning block; 702. second flange; 7021. connecting groove; 7022. limiting structure; 7122. clamping block; 7023. annular slide groove; 7123. clamping groove; 7024. arc groove; 7025. elastic connector; 7026. rope traction member; 7027. drive unit; 7127. screw; 7227. protective tube; 7327. block; 7427. drive block; 7028. positioning hole; 7029. positioning column; 703. preload gasket; 7031. perforation; 7032. pressing block. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0041] In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention. The terms "connected" and "connected" used in the present invention should be understood in a broad sense. For example, they can be fixed connections or detachable connections; they can be directly connected or indirectly connected through intermediate components. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0042] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0043] The shapes and sizes of the components in the drawings do not reflect the actual proportions of the products, and are only intended to illustrate the contents of the present invention.

[0044] The invention provides a construction method for excavating a communication channel in a water-rich sand layer, which reduces the impact on existing buildings and pipelines above a construction area by changing ground precipitation into underground vacuum precipitation.

[0045] Example 1

[0046] like Figure 1 As shown, the construction method for excavating a communication channel in a water-rich sand layer includes the following steps:

[0047] Step S1, determine the location of the communication channel 1; confirm the construction location of the communication channel 1 according to the design drawings, and make preparations for the construction.

[0048] Step S2, such as Figure 2 As shown, drilling before grouting is performed on the tunnel 3 at one end of the determined specific position in the extension direction of the connecting channel 1. The grouting drilling direction 301 is arranged radially in the circumferential direction with the connecting channel 1 as the center. After the drilling is completed, grouting is performed in the hole. The grouting slurry is mortar, which is used to expel groundwater and solidify the part to be excavated with a higher water content, so as to strengthen the soil layer strength near the connecting channel, increase the bearing capacity of the soil layer, and ensure the safety of excavation.

[0049] Step S3, determining the position of the horizontal vacuum drainage hole 2 in one of the tunnels 3 at both ends of the communication channel 1; Figure 3 As shown, the vacuum dewatering holes 2 are arranged at intervals around the outer side of the communication channel 1.

[0050] Step S4, such as Figure 4As shown, a vacuum precipitation device is arranged at the position of the vacuum precipitation hole 2; the vacuum precipitation device includes a vacuum precipitation pipe 4, a main water collecting pipe 5 and a vacuum pump 6. The vacuum precipitation pipe 4 is arranged in the vacuum precipitation hole 2, that is, the vacuum precipitation pipe 4 is arranged at intervals around the outer side of the connecting channel 1 in the circumferential direction, and each vacuum precipitation pipe 4 is connected to the main water collecting pipe 5, and the main water collecting pipe 5 is connected to the vacuum pump 6.

[0051] Specifically, the horizontal depth of the vacuum dewatering hole 2 is 6m, 10 vacuum holes are arranged circumferentially around the connecting channel 1, and the vacuum dewatering pipe 4 inserted into the stratum is wrapped with a filter mesh, which will not cause the loss of solid particles in the fine sand layer + clay layer. The dewatering effect is reliable, reducing the potential safety hazards that may occur during the excavation of the connecting channel 1, reducing the moisture content of the aquifer, and preventing the excavation surface from becoming unstable.

[0052] Step S5, draining the groundwater outside the communication channel 1 by vacuum dewatering equipment to ensure excavation safety;

[0053] Step S6, after the precipitation is completed, start excavating the communication channel 1 for a set distance; the specific excavation of the communication channel 1 adopts the step-by-step excavation method of upper and lower steps, and the excavation cycle advance is 0.5m. After each excavation advance is completed, the steel arch frame is installed, the steel mesh is hung and the shotcrete construction is carried out in time; the lower step is excavated after the upper step is excavated for 2-3m; it is required to first take out the large sample of the grille and install the temporary grille when excavating the tunnel door, and remove the temporary grille and install the formal grille after the working surface is vacated.

[0054] Step S7, repeat steps S2-S6 until the excavation is completed.

[0055] Furthermore, the existing vacuum downpipes 4 are usually connected to the main water collecting pipe 5 using ordinary flanges. Each ordinary flange needs to be connected using multiple sets of bolts and nuts in a circumferential manner. The connection operation is time-consuming, resulting in low efficiency in assembling the vacuum downpipes 4 and the main water collecting pipe 5. In order to improve the assembly efficiency of the vacuum downpipes 4 and the main water collecting pipe 5, the vacuum downpipes 4 of the present invention are connected to the main water collecting pipe 5 via a quick-connect flange structure 7.

[0056] like Figure 5 As shown, the quick-connect flange structure 7 includes a first flange 701 and a second flange 702. The first flange 701 is arranged on one of the two pipe bodies of the vacuum downpipe 4 or the main water collecting pipe 5, and the second flange 702 is arranged on the other pipe body. In this embodiment, the first flange 701 is uniformly installed on the main water collecting pipe 5, and the second flange 702 is uniformly installed at one end of the vacuum downpipe 4. In other embodiments, the first flange 701 can also be installed on the vacuum downpipe 4, and in this case, the second flange 702 is installed at one end of the main water collecting pipe 5.

[0057] like Figure 6As shown, a plurality of connecting blocks are circumferentially arranged at intervals on the end surface of the first flange 701 facing away from the main water collecting pipe 5. The connecting block has a connecting rod 7011 and a positioning block 7012 which are integrally connected and have different radial dimensions. The diameter of the connecting rod 7011 is smaller than the diameter of the positioning block 7012. The end of the connecting rod 7011 away from the positioning block 7012 is fixedly connected to the first flange 701.

[0058] like Figure 8 As shown, the second flange 702 has a connecting groove 7021 and a limiting structure 7022 . The connecting groove 7021 is used to place the positioning block 7012 . The limiting structure 7022 is used to be clamped on the connecting rod 7011 and press the positioning block 7012 to achieve the connection between the first flange 701 and the second flange 702 .

[0059] Specifically, an annular groove 7023 is arranged on the end surface of the second flange 702 facing the first flange 701, a connecting groove 7021 is arranged at the bottom of the annular groove 7023, and a limiting structure 7022 is arranged at each position close to the connecting groove 7021 in the annular groove 7023. Specifically, the limiting structures 7022 are arranged one by one with the connecting grooves 7021, and each connecting groove 7021 is correspondingly provided with a limiting structure 7022. A driving structure is connected between the limiting structures 7022 to drive the limiting structures 7022 to slide along the annular groove 7023.

[0060] like Fig. 9 As shown, in this embodiment, the limiting structure 7022 is a block arc block structure adapted to the annular slide groove 7023, that is, the shape of the limiting structure 7022 is adapted to the annular slide groove 7023, so that it can stably slide along the annular slide groove 7023. In addition, a clamping groove 7123 coaxially arranged with the annular slide groove 7023 is provided at the bottom of the annular slide groove 7023, and a clamping block 7122 for clamping in the clamping groove 7123 is integrally fixedly connected to the bottom of the limiting structure 7022, and the clamping block 7122 can slide along the clamping groove 7123. The cross-section of the clamping groove 7123 and the clamping block 7122 can be in the shape of a dovetail groove, so that the limiting structure 7022 will not be separated from the annular slide groove 7023 when sliding in the annular slide groove 7023. In this way, the limiting structure 7022 is stably connected to the second flange 702. The limiting structure 7022 has an arc groove 7024 with one end open, the opening of the arc groove 7024 faces the adjacent connecting groove 7021, and the width of the arc groove 7024 is not less than the radial dimension of the connecting rod 7011 and is less than the radial dimension of the positioning block 7012. In this way, when the first flange 701 is connected to the second flange 702, the positioning block 7012 is inserted into the connecting groove 7021, and the driving structure drives the limiting structure 7022 to slide along the annular sliding groove 7023. During the sliding process, the arc groove 7024 is clamped on the connecting rod 7011 from the open end, so as to realize the fixed connection between the first flange 701 and the second flange 702.

[0061] In this embodiment, two groups of limiting structures 7022 are provided, and the two groups of limiting structures 7022 are symmetrically arranged in the annular sliding groove 7023;

[0062] The driving structure includes an elastic connecting member 7025, a rope-like traction member 7026 and a driving unit 7027. The rope-like traction member 7026 is arranged in each group of limiting structures 7022 and is connected to a limiting structure 7022 at both ends. The two ends of the elastic connecting member 7025 are respectively connected to one end of a group of limiting structures 7022. The other ends of the two groups of limiting structures 7022 are connected to the driving unit 7027 through the rope-like traction member 7026. The driving unit 7027 pulls the two groups of limiting structures 7022 to slide along the annular groove 7023 through the rope-like traction member 7026. The specific driving unit 7027 includes a screw 7127, one end of which passes through the side wall of the second flange 702 and extends into the annular groove 7023. The length of the screw 7127 can be appropriately adjusted according to actual needs. The screw 7127 is threadedly connected to the second flange 702. In order to ensure the stability of the threaded connection, a fixing block is integrally provided at the position where the screw 7127 is installed on the second flange 702, thereby thickening the size of the position, thereby increasing the threaded connection path between the screw 7127 and the second flange 702 and ensuring the stability of the connection.

[0063] One end of the screw 7127 that passes through the annular groove 7023 is fixedly connected to the rope-like traction members 7026 on both sides. When the screw 7127 is rotated in one direction, the rope-like traction members 7026 on both sides gradually wrap around the screw 7127, thereby tightening the rope-like traction members 7026. At this time, the limiting structure 7022 is clamped on the connecting rod 7011 under the pulling of the rope-like traction member 7026; when the screw 7127 is rotated in the other direction, the rope-like traction member 7026 gradually separates from the screw 7127, and under the action of the elastic connecting member 7025, the limiting structure 7022 separates from the limitation of the positioning block 7012, so that the first flange 701 and the second flange 702 can be disassembled.

[0064] Furthermore, a protective tube 7227 is sleeved on the outer side of one end of the screw rod 7127 extending into the annular groove 7023, one end of the protective tube 7227 is fixedly connected to the annular groove 7023, and the other end is rotatably matched with the screw rod 7127, and the connection position of the rope-like traction member 7026 and the screw rod 7127 is located inside the protective tube 7227. In this way, the position where the rope-like traction member 7026 is wound around the screw rod 7127 is located inside the protective tube 7227, so that the rope-like traction member 7026 wound around the screw rod 7127 will not interfere with the normal threaded connection between the screw rod 7127 and the second flange 702. In addition, a stopper 7327 is fixedly provided on one end of the screw rod 7127 extending into the protective tube 7227, and the stopper 7327 can prevent the rope-like traction member 7026 from being separated from the screw rod 7127 from the end of the screw rod 7127 when it is normally wound around the screw rod 7127. At the same time, in order to facilitate the screwing of the screw 7127, a regular polygonal driving block 7427 is fixedly connected to one end of the screw 7127 on the outside of the second flange 702. The driving block 7427 facilitates the force application tool to apply force, thereby facilitating the driving of the screw 7127 to rotate.

[0065] Furthermore, in order to ensure a stable connection between the first flange 701 and the second flange 702, the quick connection flange structure 7 also includes a pre-tightening gasket 703, which has a through hole 7031 corresponding to the positioning block 7012, and each through hole 7031 is provided with a clamping block 7032 on the side facing the second flange 702. When the first flange 701 and the second flange 702 are connected, the limiting structure 7022 slides along the annular groove 7023 and cooperates with the clamping block 7032, so that the first flange 701 is stably connected to the second flange 702. In addition, in order to ensure that the limiting structure 7022 and the clamping block 7032 are stably matched, that is, when the limiting structure 7022 slides toward the clamping block 7032, the pre-tightening gasket 703 cannot rotate relative to each other, two positioning columns 7029 are provided on the end face of the second flange 702, and corresponding positioning holes 7028 that cooperate with the positioning columns 7029 are provided on the pre-tightening gasket 703 and the first flange 701, such as Figure 5 , Figure 7 As shown, when the first flange 701 and the second flange 702 are connected, the positioning column 7029 can achieve a quick connection by passing through the pre-tightening gasket 703 and the positioning hole 7028 on the first flange 701.

[0066] Furthermore, in order to facilitate the tightening fit between the limiting structure 7022 and the pre-tightening gasket 703, the top surface of the limiting structure 7022 is inclined and tilted upward from the end adjacent to the connecting groove 7021 to the end away from the connecting groove 7021, and the clamping block 7032 is inclined toward one side of the second flange 702, and the inclination direction is opposite to that of the limiting structure 7022.

[0067] In this way, if Fig. 9As shown, when the first flange 701 and the second flange 702 are connected, the positioning block 7012 on the first flange 701 extends into the connecting groove 7021 on the second flange 702, and the rope-like traction member 7026 is wound around the screw 7127 by screwing the screw 7127. At the same time, the rope-like traction member 7026 pulls the limiting structure 7022 to be clamped on the connecting rod 7011. During the clamping process, the limiting structure 7022 gradually presses the pressing block 7032 on the pre-tightening gasket 703, thereby further ensuring the stability of the connection between the first flange 701 and the second flange 702. When the first flange 701 and the second flange 702 need to be disassembled, the screw 7127 is rotated in the opposite direction. Under the action of the elastic connecting member 7025, the limiting structure 7022 gradually breaks away from the restriction on the positioning block 7012, so that the positioning block 7012 is pulled out from the connecting groove 7021, and the first flange 701 and the second flange 702 are separated. When operating the quick-connect flange structure 7 of the present invention, compared with installing multiple sets of bolt and nut assemblies in the prior art, only one screw rod 7127 needs to be screwed, which is more convenient to operate, thereby improving the assembly efficiency of the vacuum downcomer 4 and the main water collecting pipe 5.

[0068] It should be understood that the above description is merely exemplary and the embodiments of the present application do not limit this.

[0069] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A vacuum dewatering device used in excavating a communication channel in a water-rich sand layer, characterized in that: The following steps are involved: Step S1, determining the location of the communication channel (1); Step S2, drilling holes and performing grouting at the determined locations to reinforce the construction area of ​​the communication channel (1); Step S3, determining the position of a horizontal vacuum drainage hole (2) in one of the tunnels (3) at both ends of the communication channel (1); Step S4, arranging vacuum dewatering equipment at the location of the vacuum dewatering hole (2); Step S5, draining the groundwater outside the communication channel (1) by vacuum dewatering equipment to ensure excavation safety; Step S6, after the precipitation is completed, start excavating the communication channel (1) to set the distance; Step S7, repeating steps S2-S6 until the excavation is completed; In step S4, the vacuum dewatering equipment comprises a vacuum dewatering pipe (4), a main water collecting pipe (5) and a vacuum pump (6), wherein the vacuum dewatering pipes (4) are arranged at intervals around the outer side of the communication channel (1), and each vacuum dewatering pipe (4) is connected to the main water collecting pipe (5) via a quick connection flange structure (7), and the main water collecting pipe (5) is connected to the vacuum pump (6); The quick connection flange structure (7) comprises a first flange (701) and a second flange (702), wherein the first flange (701) is arranged on one of the pipe bodies of the vacuum downcomer (4) or the main water collecting pipe (5), and the second flange (702) is arranged on the other pipe body; A plurality of connection blocks are arranged at intervals in the circumferential direction on the end surface of the first flange (701) away from the tube body connected thereto, the connection block comprising a connection rod (7011) and a positioning block (7012) which are integrally connected and have different radial dimensions, the diameter of the connection rod (7011) being smaller than the diameter of the positioning block (7012), and one end of the connection rod (7011) away from the positioning block (7012) being fixedly connected to the first flange (701); The second flange (702) is provided with a connecting groove (7021) and a limiting structure (7022); the connecting groove (7021) is used to place a positioning block (7012); the limiting structure (7022) is used to be clamped on the connecting rod (7011) and press the positioning block (7012) to achieve connection between the first flange (701) and the second flange (702); An annular sliding groove (7023) is arranged on the end surface of the second flange (702) facing the first flange (701); the connecting groove (7021) is arranged at the bottom of the annular sliding groove (7023); each position close to the connecting groove (7021) in the annular sliding groove (7023) is provided with a limiting structure (7022); and a driving structure is connected between the limiting structures (7022) to drive the limiting structures (7022) to slide along the annular sliding groove (7023); The limiting structures (7022) are provided in two groups, and the two groups of limiting structures (7022) are symmetrically arranged in the annular sliding groove (7023); The driving structure comprises an elastic connecting member (7025), a rope-shaped traction member (7026) and a driving unit (7027); the rope-shaped traction member (7026) is arranged in each group of limiting structures (7022) and is respectively connected to a limiting structure (7022) at both ends; the two ends of the elastic connecting member (7025) are respectively connected to one end of a group of limiting structures (7022); the other ends of the two groups of limiting structures (7022) are connected to the driving unit (7027) via the rope-shaped traction member (7026); and the driving unit (7027) pulls the two groups of limiting structures (7022) to slide along the annular sliding groove (7023) via the rope-shaped traction member (7026).

2. The vacuum dewatering equipment used in excavating a water-rich sand layer communication channel according to claim 1 is characterized in that: The limiting structure (7022) is an arc-shaped block structure adapted to the annular sliding groove (7023), and the limiting structure (7022) is provided with an arc-shaped groove (7024) with one end open, the opening of the arc-shaped groove (7024) faces the adjacent connecting groove (7021), and the width of the arc-shaped groove (7024) is not less than the radial dimension of the connecting rod (7011) and is less than the radial dimension of the positioning block (7012).

3. The vacuum dewatering equipment used in excavating a water-rich sand layer communication channel according to claim 1 is characterized in that: The driving unit (7027) comprises a screw rod (7127), one end of which passes through the side wall of the second flange (702) and extends into the annular slide groove (7023), the screw rod (7127) is threadedly connected to the second flange (702), and one end of the screw rod (7127) that passes through the annular slide groove (7023) is respectively fixedly connected to the rope-like traction members (7026) on both sides, and when the screw rod (7127) is rotated, the rope-like traction members (7026) on both sides are wound around or detached from the screw rod (7127).

4. The vacuum dewatering equipment used in excavating a water-rich sand layer communication channel according to claim 3 is characterized in that: A protective tube (7227) is sleeved on the outer side of one end of the screw rod (7127) extending into the annular slide groove (7023); one end of the protective tube (7227) is fixedly connected to the annular slide groove (7023), and the other end is rotatably matched with the screw rod (7127); the connection position between the rope-shaped traction member (7026) and the screw rod (7127) is located inside the protective tube (7227).

5. The vacuum dewatering equipment used in excavating a water-rich sand layer communication channel according to claim 2, characterized in that: The quick-connect flange structure (7) further comprises a pre-tightening gasket (703), wherein the pre-tightening gasket (703) has a through hole (7031) corresponding to the positioning block (7012), and each through hole (7031) is provided with a pressing block (7032) on one side facing the second flange (702). When the first flange (701) and the second flange (702) are connected, the limiting structure (7022) slides and cooperates with the pressing block (7032), so that the first flange (701) is stably connected to the second flange (702).

6. The vacuum dewatering equipment used in excavating a communication channel in a water-rich sand layer according to claim 5, characterized in that: The top surface of the limiting structure (7022) is arranged to be inclined, and is inclined upward from an end adjacent to the connecting groove (7021) to an end away from the connecting groove (7021), and the pressing block (7032) is arranged to be inclined toward one side of the second flange (702), and the inclination direction is arranged opposite to that of the limiting structure (7022).

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