CN113089704A

CN113089704A - Water guide structure for foundation pit dewatering of sand bed foundation

Info

Publication number: CN113089704A
Application number: CN202110380806.8A
Authority: CN
Inventors: 张敏; 周付彬
Original assignee: Shandong Southern Shandong Geological Engineering Investigation Institute (second Geological Brigade Of Shandong Geological Survey Bureau)
Current assignee: Shandong Southern Shandong Geological Engineering Investigation Institute (second Geological Brigade Of Shandong Geological Survey Bureau)
Priority date: 2021-04-09
Filing date: 2021-04-09
Publication date: 2021-07-09

Abstract

The invention relates to a sand bed foundation pit dewatering water guide structure which comprises a plurality of main pipelines, a plurality of transverse branch pipes, a plurality of longitudinal branch pipes and gauze wrapped outside each branch pipe. Through holes are distributed on the pipe wall of each branch pipe. Partial main pipeline encircles the round and forms the frame and is equipped with a main pipeline along longitudinal extension in the frame at least apart from foundation ditch sideline inboard. And transverse branch pipes and longitudinal branch pipes are distributed in a unit frame surrounded by the main pipeline in a crossed manner. The cross joint between the main pipelines and the branch pipelines are communicated. The cross joint between the transverse branch pipe and the longitudinal branch pipe is a non-communicated matching structure. A main pipeline in the outer frame is connected to the water collecting tank through a pipeline. This patent can be at the ground not disturbed basically, ensure under the firm safe prerequisite of foundation ditch, the steady depth of fall of cooperation tube-well carries out precipitation, has overcome the geological environment construction of unfavorable precipitation, causes the problem of unstability destruction to foundation ditch and ground easily, has established the basic construction condition.

Description

Water guide structure for foundation pit dewatering of sand bed foundation

Technical Field

The invention relates to the technical field of foundation pit dewatering water guide of a sand bed foundation, in particular to a foundation pit dewatering water guide structure of the sand bed foundation, which can be matched with pipe well dewatering to be applied to deep foundation pit dewatering scenes, and overcomes the defects that underground water is abundant, the water-bearing layer of the sand bed foundation has extremely strong permeability and the foundation pit and the foundation are damaged by instability due to the adoption of strong dewatering of a pipe well.

Background

The traditional foundation pit dewatering and water guiding mode mainly comprises foundation pit open trench drainage and well point dewatering. Under certain geological environment conditions which are not beneficial to precipitation, such as shallow water level and sand layer geological scenes with extremely strong water permeability of the foundation, the conventional precipitation scheme can not ensure the stability of the foundation and the normal operation of foundation construction. The construction methods of open ditch drainage and light well point dewatering are adopted at present, the construction limit of pipe well dewatering is less, but the sand bed foundation and the foundation pit are easy to be damaged by continuous strong dewatering for months.

Disclosure of Invention

In order to solve the problems in the prior art, the sand bed foundation pit dewatering water guide structure provided by the invention can be matched with a pipe well to stably reduce the depth for dewatering on the premise that the foundation is basically not disturbed and the stability and safety of the foundation pit are ensured, so that the problems of instability and damage to the foundation pit and the foundation due to the deep foundation pit dewatering, abundant underground water, and a geological environment with strong permeability of the sand bed foundation and a sand bed aquifer are solved, and the foundation construction condition under the geological environment condition of unfavorable dewatering is established.

The technical scheme adopted by the invention for solving the technical problems is as follows: the utility model provides a sand bed foundation ditch precipitation water guide structure, includes many trunk lines, many spinal branch pipelines and parcel and is in the outer gauze of branch pipeline. And through holes are distributed on the pipe wall of the branch pipe.

Partial trunk line encircles the round at a distance from foundation ditch sideline inboard and forms the frame and be equipped with a trunk line along longitudinal extension in the frame, perhaps be equipped with many along longitudinal extension's trunk line, each trunk line in the frame sets up alternately on the transverse direction.

The branch pipelines are divided into a plurality of transverse branch pipes and a plurality of longitudinal branch pipes.

And transverse branch pipes and longitudinal branch pipes are distributed in the unit frame surrounded by the main pipeline in a crossed manner, and the transverse branch pipes and the longitudinal branch pipes are crossed in each unit frame to form a plurality of grids.

And the cross nodes between the main pipelines and the branch pipelines are communicated. And the cross joint between the transverse branch pipe and the longitudinal branch pipe is a non-communicated matching structure.

And one main pipeline in the outer frame is connected to the water collecting tank through a pipeline.

The precipitation water guide structure described by the scheme is formed into a square grid pipe network form and is buried in a sand layer foundation, the pipe network structure is generally buried in a depth of 0.5 m below a basement, and the disturbed part of the sand layer foundation is compacted by adopting water to flush sand when the groove is buried. The pipe network can be properly inclined downwards towards the direction of the water collecting tank so as to facilitate the self-flowing. The main pipeline and the branch pipelines can adopt thick-wall galvanized steel pipes, and the connection mode can be selected by welding or screw thread connection.

The pipe diameter of the main pipeline is about 13 cm, the water collecting and guiding effects are achieved, incoming water of each branch pipeline is collected and guided into a water collecting pool arranged outside the foundation, and the incoming water is pumped out by a water pump matched with the main pipeline to be discharged in a centralized mode.

The pipe diameter of the branch pipeline is about 5 cm, through holes distributed on the pipe wall form filter holes, and double layers or multiple layers of nylon gauze with the diameter not less than 80 meshes are coated outside the filter holes. The branch pipeline is matched with the gauze and is used for filtering fine-particle soil and ensuring that fine particles are not taken away by water flow so as to prevent the foundation from being unstable.

Furthermore, the transverse branch pipe faces the end port of the longitudinal branch pipe and is provided with a sealing plate, an insertion pipe extending axially outwards is formed on the sealing plate, and correspondingly, a hole capable of being matched and inserted with the insertion pipe is formed in the longitudinal branch pipe. The pore canal and the tube cavity of the longitudinal branch tube are of a non-communicated structure.

Further, the shrouding at horizontal branch pipe port department is the cambered surface shrouding of indent, and the intubate that is equipped with on this cambered surface shrouding sets up respectively for flat pipe and the upper and lower edge that is close to the cambered surface shrouding, correspondingly, pore in the vertical branch pipe is flat pore.

The flat pipe ports corresponding to two ends of the flat hole channel arranged in the longitudinal branch pipe can be inserted in the flat hole channel, and the concave surfaces of the two cambered surface sealing plates can be fully embraced with the pipe wall of the longitudinal branch pipe.

Further, the shrouding at horizontal branch pipe port department is the cambered surface shrouding of indent, and the intubate that is equipped with on this cambered surface shrouding is the pipe and this pipe with horizontal branch pipe is coaxial, correspondingly, the pore in the vertical branch pipe is the circular pore.

The circular pipe ports corresponding to two ends of a circular hole arranged in the longitudinal branch pipe can be inserted in the circular hole, and the concave surfaces of the two cambered surface seal plates can be fully embraced with the pipe wall of the longitudinal branch pipe. Or, a partition board is arranged in the circular hole channel, tapered holes are formed in the end faces of the two sides of the partition board respectively, correspondingly, the free end port of the circular pipe is a tapered end, the circular pipe ports corresponding to the two ends of the circular hole channel arranged in the longitudinal branch pipe can be inserted into the tapered holes on the same side respectively, and the concave surfaces of the two cambered surface sealing plates can be fully embraced with the pipe wall of the longitudinal branch pipe.

Further, the longitudinal branch tube includes a pair of tube bodies and a connection ring interposed between the pair of tube bodies. The tube body is connected with the two ends of the connecting ring through a thread structure. The pore canal formed in the longitudinal branch pipe is arranged in the connecting ring, namely the intubation tube on the transverse branch pipe is connected with the connecting ring.

Furthermore, a plurality of protruding ribs extending along the axial direction are formed on the outer wall of the branch pipeline, and the protruding ribs are distributed around the outer wall at intervals. The through holes are arranged in the grooves between two adjacent convex ribs, and cotton fabrics are filled in the grooves formed between the adjacent convex ribs. And part of the cotton fabric extends into the pipe cavity of the branch pipe through the through hole.

The invention has the beneficial effects that: this patent can be at the ground not disturbed basically, ensure under the firm safe prerequisite of foundation ditch, the steady depth of fall of cooperation tube-well carries out precipitation, has overcome the geological environment construction of unfavorable precipitation, causes the problem of unstability destruction to foundation ditch and ground easily, has established the basic construction condition.

The foundation construction method is suitable for deep foundation pits, the foundation soil layer is a water-bearing layer-sand layer with extremely strong water permeability, the thick complex geological environment is thick, and the foundation construction progress under the complex geological environment is guaranteed. Specifically, 1) for the situation that the design of foundation pit dewatering is seriously inconsistent with the actual situation after foundation pit excavation and other measures and conditions are not available on site, the dewatering water guide structure can be adopted to cooperate with dewatering; 2) the precipitation water guide structure has the advantages of convenient market material acquisition, simple processing, high implementation efficiency, easy quality control, and bearable increased cost, and greatly accelerates the construction period of the foundation; 3) the foundation pit construction site is often narrow and small, compact, and the construction operation is alternately, compares with increasing the pipe shaft precipitation measure, has avoided mechanical equipment to advance the field once more and the on-the-spot occupation of land, has avoided mud to discharge, has avoided the cross operation, has avoided the uncontrollable condition of well-forming quality and deepening effect, has reduced the precipitation power consumption cost simultaneously, has also reduced the normal damage of water pump and has changed, the maintenance cost.

Drawings

Fig. 1 is a schematic diagram of the overall layout structure of the scheme of the patent.

Fig. 2 is a schematic sectional view of the branch duct.

Fig. 3 is a schematic structural diagram of cross matching of the transverse branch pipes and the longitudinal branch pipes.

Fig. 4 is another structure diagram of the cross matching of the transverse branch pipe and the longitudinal branch pipe.

Fig. 5 is a schematic view of a third structure (split state) in which the transverse branch pipes and the longitudinal branch pipes are in cross fit.

Fig. 6 is a schematic view of the connection structure of the embodiment shown in fig. 5.

Fig. 7 is a schematic diagram of a fourth structure of cross-fitting of the transverse branch pipes and the longitudinal branch pipes.

Figure 8 is a schematic diagram of a configuration of longitudinal manifolds that can be used in the embodiment of figure 7.

Fig. 9 is another structural diagram of the branch duct.

In the figure: 10 side lines of a foundation pit, 20 water collecting tanks, a conical surface notch and b conical surface port; the device comprises a main pipeline 1, a branch pipeline 2, a transverse branch pipeline 21, a flat pipe 211, a round pipe 212, a clamping groove 213, an arc-shaped groove 214, a longitudinal branch pipeline 22, a pipe body 22a, a connecting ring 22b, a flat hole 221, a round hole 222, a partition plate 223, a groove 224, a through hole 23, a rib 24, cotton fabric 25 and a nylon gauze.

Detailed Description

The structures, proportions, and dimensions shown in the drawings and described in the specification are for understanding and reading the present disclosure, and are not intended to limit the scope of the present disclosure, which is defined in the claims, and are not essential to the skilled in the art. In addition, the terms "upper", "lower", "front", "rear" and "middle" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the relative positions may be changed or adjusted without substantial technical changes.

Fig. 3 in fig. 1 shows a water guide structure for lowering water in a foundation pit of a sand foundation, which comprises a plurality of main pipelines 1, a plurality of branch pipelines 2 and nylon gauze 3 wrapped outside the branch pipelines 2. The branch ducts 2 are divided into a plurality of transverse branch ducts 21 and a plurality of longitudinal branch ducts 22. Through holes 23 are distributed on the pipe wall of the branch pipe 2.

Partial trunk lines 1 surround a circle to form an outer frame at a distance from the inner side of the foundation pit sideline 10, two trunk lines 1 extending longitudinally are arranged in the outer frame, and the two trunk lines are uniformly distributed at intervals in the transverse direction. In some embodiments, a main pipe 1 extending in the longitudinal direction may be provided in the outer frame. Or in some embodiments, more than three main pipes 1 extending along the longitudinal direction are arranged in the outer frame, and the main pipes are distributed in the transverse direction.

In the unit frame(s) enclosed by the main pipe 1, transverse branch pipes 21 and longitudinal branch pipes 22 are (all) distributed crosswise. In the solution shown in fig. 1, five transverse branch pipes 21 and one longitudinal branch pipe 22 are distributed crosswise in each unit frame. The lateral branch pipes 21 and the longitudinal branch pipes 22 are formed to intersect in a plurality of (long) lattices in each unit frame.

The cross joint between the main pipelines 1 and the branch pipelines 2(21 and 22) are communicated.

The cross joint between the transverse branch pipe 21 and the longitudinal branch pipe 22 is a non-communicated matching structure, which is shown in the scheme of fig. 3 to 8 in detail.

One main pipe in the outer frame is connected to the sump 20 through a pipe.

The precipitation water guide structure described by the scheme is formed into a strip-shaped pipe network and is buried in a sand layer foundation, the pipe network structure is generally buried in a position 0.5 m below a base, and the disturbed part of the sand layer foundation is compacted by adopting water to flush sand when the pipe network structure is buried and grooved. The pipe network is preferably inclined moderately downwards towards the sump 20 for gravity flow, i.e. the formed pipe network is inclined downwards from side a towards side B.

The main pipeline 1 and the branch pipelines 2 can be made of thick-wall galvanized steel pipes, and the connection mode can be welding or screw thread connection.

The spacing between each pipeline is generally 5 meters to 6 meters, and can be more than 6 meters or less than 5 meters according to the specific needs determined by the field situation.

The pipe diameter of the main pipe 1 is preferably about 13 cm. The main pipeline 1 plays a role in collecting and guiding water, and is used for collecting and guiding the water coming from each branch pipeline 2 into a water collecting pool 20 arranged outside the foundation and then pumping out the water by a water pump matched with the water collecting pool to be intensively discharged.

The pipe diameter of the branch pipe 2 is preferably about 5 cm. The through holes 23 distributed on the pipe wall of the branch pipe 2 form filtering holes. The nylon gauze 3 coated outside the branch pipeline 2 is double-layer or multi-layer, and the density of the gauze is not lower than 80 meshes. The branch pipeline is used for filtering fine-particle soil after being matched with the nylon gauze, so that fine particles are prevented from being taken away by water flow, and the instability of a foundation is prevented.

As shown in fig. 4 to 8, a sealing plate is disposed at an end of the lateral branch tube 21 facing the longitudinal branch tube 22, and an axially outwardly extending insertion tube is formed on the sealing plate, and correspondingly, a hole capable of being inserted into the insertion tube is formed in the longitudinal branch tube 22. The pore canal and the tube cavity of the longitudinal branch tube are of a non-communicated structure.

In fig. 4, the sealing plate is a flat plate and is provided with an upper layer and a lower layer of insertion tubes, and the insertion tubes are strip-shaped flat tubes 211 when viewed from the cross section of the insertion tubes. The hole channels in the longitudinal branch pipes are correspondingly set to be flat hole channels 221. The flat tubes 211 corresponding to both ends of each flat channel 221 provided in the longitudinal branch tube 22 can be inserted into both ends of the flat channel 221. Under this implementation structure, the tube cavities of the transverse branch tubes 21, the flat channels 221 and the flat tubes 211 are connected to form a communication channel. The structure in which the lateral branch pipes and the longitudinal branch pipes are connected in an inserted manner has a poor stress effect, and the depth of the grooves is much shallower when the structure is buried compared with the embodiment shown in fig. 3.

As shown in fig. 5 to 6, the sealing plates at the ports of the transverse branch pipes 21 are concave arc sealing plates, the insertion pipes on the arc sealing plates are flat pipes 211, and the flat pipes 211 are respectively arranged near the upper and lower edges of the arc sealing plates, and correspondingly, the holes in the longitudinal branch pipes 22 are flat holes 221. The flat pipe 211 ports corresponding to the two ends of the flat hole channel 221 arranged in the longitudinal branch pipe 22 can be inserted in the flat hole channel 221 and the concave surfaces of the two cambered surface closing plates can be fully embraced with the pipe wall of the longitudinal branch pipe 22. As shown, the flat tube 211 on the left side of the longitudinal branch 22 is terminated with a tapered notch a, and the flat tube 211 on the right side of the longitudinal branch 22 is terminated with a tapered port b. A tapered port b is provided that is capable of being inserted into the tapered slot a (see fig. 6). The surface of the sealing plate between the two flat tubes 211 is an arc-shaped groove 214 which can be contacted with the tube wall of the longitudinal branch tube between the two flat hole channels 221. A clamping groove 213 is formed between the concave end of the sealing plate and the flat pipe 211, and the inner surface of the clamping groove can be contacted with the pipe wall of the longitudinal branch pipe which is positioned at the outer side of the two flat hole channels 221.

The solution described in the above paragraph significantly optimizes the stress of the structure in which the lateral branch pipes are connected to the longitudinal branch pipes in a plug-in manner, but has the problem that the cross-sectional equivalent of the lateral branch pipes at the cross-connect is relatively small.

As shown in fig. 7, the sealing plate at the port of the transverse branch pipe 21 is an inward concave arc sealing plate, the insertion tube on the arc sealing plate is a circular tube 212, the circular tube 212 is coaxial with the transverse branch pipe 21, and correspondingly, the hole in the longitudinal branch pipe 22 is a circular hole 222.

In the illustrated scheme, a partition plate 223 is disposed in the circular duct 222, tapered holes are respectively formed on end surfaces on both sides of the partition plate 223, correspondingly, a free end port of the circular tube 212 is a tapered end, ports of the circular tube 212 corresponding to both ends of the circular duct 222 disposed in the longitudinal branch pipe 22 can be respectively inserted into the tapered holes on the same side, and concave surfaces of the two arc surface closing plates can fully embrace a wall of the longitudinal branch pipe. A clamping groove 213 is formed between the concave end of the sealing plate and the circular tube 212, and the inner surface of the clamping groove can be contacted with the tube wall of the longitudinal branch tube outside the circular hole 222.

The scheme described in the upper section not only obviously optimizes the stress of the structure of the plug connection of the transverse branch pipes and the longitudinal branch pipes, but also can flexibly adjust the size of the cross section equivalent of the transverse branch pipe 21 relative to the cross section equivalent of the longitudinal branch pipe at the cross connection position. The size of the equivalent cross section of the lateral branch pipe 21 relative to the equivalent cross section of the longitudinal branch pipe can be adjusted by the size of the tapered end of the tapered pipe 212 and the hole diameter of the partition plate 223. The cross-sectional equivalent of the longitudinal branch pipes at the intersection is increased by providing a groove 224 on the outer wall of the circular hole 222 where the partition 223 is provided (the smaller the hole diameter of the shaft hole on the partition 223, the deeper the groove 224 can be provided).

In the scheme shown in fig. 7, the circular pipe ports corresponding to the two ends of the circular hole channel arranged in the longitudinal branch pipe can be inserted in the circular hole channel, and the concave surfaces of the two cambered surface seal plates can be fully embraced with the pipe wall of the longitudinal branch pipe.

As shown in fig. 7 and 8, the longitudinal branch tube 22 includes a pair of tube bodies 22a and a connecting ring 22b interposed between the pair of tube bodies 22 a. The tube body 22a is connected to both ends of the connection ring 22b by a screw structure. The hole formed in the longitudinal branch tube 22 is formed in the connecting ring 22b, i.e. the cannula of the transverse branch tube 21 is connected to the connecting ring.

The upper description scheme can conveniently process the longitudinal branch pipe, facilitate field installation and ship pipe fittings, is favorable for realizing production and installation standardized operation, and improves the installation operation efficiency.

As shown in fig. 9, a plurality of ribs 24 extending in the axial direction are formed on the outer wall of the branch duct 2, and the plurality of ribs 24 are distributed at intervals around the outer wall (of the branch duct 2). The through holes 23 are arranged in the grooves between two adjacent protruding ribs 24, and the grooves formed between the adjacent protruding ribs 24 are filled with cotton fabric 25. And part of the cotton fabric 25 extends into the pipe cavity of the branch pipe through the through hole.

The upper description scheme can properly increase the distribution density of the through holes 23 and ensure the pipe cavity rigidity of the branch pipe 2 when the aperture is properly increased, and water infiltrated through the multiple layers of nylon yarn nets can be rapidly gathered in the grooves formed by the ribs and flows into the pipe cavity to be discharged, so that the flowability of the infiltrated water is better. The cotton fabric 25 is arranged in the grooves between the convex ribs, a layer of gauze can be wrapped outside the pipe, the conical through holes with large opening ends at the outer ports can be arranged corresponding to the through holes 23, and the cotton fabric plays a role of capillary, so that the drainage and water guide efficiency is accelerated.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Many modifications may be made to the present invention without departing from the spirit or scope of the general inventive concept, and it will be apparent to those skilled in the art that changes and modifications may be made to the above-described embodiments without departing from the spirit or scope of the invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. The utility model provides a sand bed foundation ditch precipitation water guide structure which characterized in that: the device comprises a plurality of main pipelines, a plurality of branch pipelines and a gauze wrapped outside the branch pipelines, wherein through holes are distributed on the pipe walls of the branch pipelines; the branch pipelines are divided into a plurality of transverse branch pipes and a plurality of longitudinal branch pipes;

part of the main pipelines surround a circle to form an outer frame from the inner side of the side line of the foundation pit, and one main pipeline extending along the longitudinal direction is arranged in the outer frame, or a plurality of main pipelines extending along the longitudinal direction are arranged in the outer frame, and all the main pipelines in the outer frame are arranged at intervals in the transverse direction;

transverse branch pipes and longitudinal branch pipes are distributed in a unit frame surrounded by the main pipeline in a crossed manner, and the transverse branch pipes and the longitudinal branch pipes are crossed in each unit frame to form a plurality of grids;

the cross nodes between the main pipelines and the branch pipelines are communicated;

the cross joint between the transverse branch pipe and the longitudinal branch pipe is a non-communicated matching structure;

a main pipeline in the outer frame is connected to the water collecting tank through a pipeline.

2. The sand bed foundation pit dewatering water guide structure of claim 1, characterized in that: the bottom surface of the foundation pit with the main pipeline and the branch pipeline is an inclined surface which inclines downwards from one side of the main pipeline and the branch pipeline, which deviates from the water collecting tank, to one side of the water collecting tank.

3. The sand bed foundation pit dewatering water guide structure of claim 1, characterized in that: the main pipeline and/or the branch pipelines are galvanized steel pipes.

4. The sand bed foundation pit dewatering water guide structure of claim 1, characterized in that: the pipe diameter of the main pipeline is 8 cm-18 cm; the pipe diameter value of the branch pipeline is 3cm to 7 cm.

5. The sand bed foundation pit dewatering water guide structure of claim 1, characterized in that: the outside of the branch pipeline is wrapped with a plurality of layers of gauze, and the gauze is preferably a nylon gauze with the mesh of not less than 80.

6. The sand bed foundation pit dewatering water guide structure of any one of claims 1-5, characterized in that: a sealing plate is arranged at one end port of the transverse branch pipe facing the longitudinal branch pipe, an insertion pipe extending outwards in the axial direction is formed on the sealing plate, and a pore passage capable of being matched and inserted with the insertion pipe is correspondingly formed in the longitudinal branch pipe; the pore canal and the tube cavity of the longitudinal branch tube are of a non-communicated structure.

7. The sand bed foundation pit dewatering water guide structure of claim 6, characterized in that: the sealing plates at the ports of the transverse branch pipes are concave cambered surface sealing plates, the insertion pipes arranged on the cambered surface sealing plates are flat pipes and are respectively arranged close to the upper edges and the lower edges of the cambered surface sealing plates, and correspondingly, the pore passages in the longitudinal branch pipes are flat pore passages;

8. The sand bed foundation pit dewatering water guide structure of claim 6, characterized in that: the sealing plate at the end of the transverse branch pipe is an inwards concave arc surface sealing plate, an insertion pipe arranged on the arc surface sealing plate is a circular pipe, the circular pipe is coaxial with the transverse branch pipe, and correspondingly, a pore passage in the longitudinal branch pipe is a circular pore passage;

the circular pipe ports corresponding to two ends of a circular hole channel arranged in the longitudinal branch pipe can be inserted in the circular hole channel, and the concave surfaces of the two cambered surface sealing plates can be fully embraced with the pipe wall of the longitudinal branch pipe; alternatively, the first and second electrodes may be,

the circular hole channel is internally provided with a partition plate, two side end faces of the partition plate are respectively provided with a conical hole, correspondingly, the free end port of the circular pipe is a conical end, the circular pipe ports corresponding to the two ends of the circular hole channel arranged in the longitudinal branch pipe can be respectively inserted into the conical holes at the same side, and the concave surfaces of the two cambered surface sealing plates can be fully embraced with the pipe wall of the longitudinal branch pipe.

9. The sand bed foundation pit dewatering water guide structure of claim 6, characterized in that: the longitudinal branch pipe comprises a pair of pipe bodies and a connecting ring arranged between the pair of pipe bodies; the pipe body is connected with the two ends of the connecting ring through a thread structure; and the pore canal formed in the longitudinal branch pipe is arranged in the connecting ring.

10. The sand bed foundation pit dewatering water guide structure of any one of claims 1-6, characterized in that: the outer wall of the branch pipeline is provided with a plurality of protruding ribs extending along the axial direction, and the protruding ribs are distributed around the outer wall at intervals.