CN111851588A - A pipe jacking well structure and its construction method - Google Patents

Abstract

The invention discloses a pipe jacking well structure and a construction method thereof, comprising a plurality of steel sheet piles that are vertically and detachably inserted into the soil, and the plurality of the steel sheet piles are enclosed to form a hollow construction space; The inner side of the steel sheet pile is fixed with at least one layer of surrounding purlin structure; the surrounding purlin structure includes a plurality of surrounding purlins fixed on the inner side of the steel sheet pile, a plurality of the surrounding purlins are fixed in sequence and connected end to end, each The bottoms of the purlins are all provided with support pieces, and gussets are connected between adjacent purlins; the lower part of the steel sheet pile is provided with a caisson body. The pipe jacking shaft structure and the construction method of the invention can not only take advantage of the advantages of convenient construction and high efficiency of steel sheet piles, but also take advantage of the advantages of high rigidity of reinforced concrete caisson, high side wall bearing capacity, good integrity and high safety. Maximize efficiency, economy and safety, so as to effectively shorten the construction period and reduce the project cost.

Description

A pipe jacking well structure and its construction method

technical field

The invention relates to the field of underground building structures and municipal engineering, in particular to a pipe jacking well structure and a construction method thereof.

Background technique

Due to the lack of investment in environmental governance and the fragile ecological environment system, the problem of environmental pollution is more prominent. Especially in the field of water environment, the pipe network system is not perfect, the direct discharge of domestic sewage is still common, the water ecology is seriously damaged, and there are many environmental hazards. In the specific implementation process of the pipeline network project, the construction method of the pipeline should be determined after comprehensive comparison of technology and economy according to the characteristics of the soil layer where the pipeline is located, the diameter of the pipeline, the groundwater level, nearby underground and above-ground buildings and other factors. When the excavation conditions are met, the pipeline can be laid in the form of open trench excavation or the support excavation can be used; when the pipeline is buried deep and the excavation face is limited or cannot be graded due to soil conditions, pipe jacking or excavation can be used. Traction and other underground excavation methods for construction.

In the prior art, in order to improve the water environment, the pipe network is generally transformed for the existing sewage pipe network in the old city. During the renovation process, except for some main pipes, most of the branch pipes of the sewage pipe network are deep into the community. If you choose to excavate in the community, it will have a great impact on the lives of nearby residents. At the same time, due to the narrow roads in the community, There are old houses on both sides of the road, and open-cut construction has greater risks. Therefore, the open-cut construction method is the main pipeline construction method in these projects.

According to the feedback of actual engineering experience, the pipeline constructed by traction method will show undulations in the soil layer, which is easy to accumulate over time and affect the drainage effect. In many areas, when choosing the underground excavation method, the pipe jacking method is preferred. The pipe jacking well structure is generally constructed by the caisson method or the reverse method. Among them, the construction personnel can work outside the well during the construction of the caisson method, the operation process is relatively safe, and the impact of less soil excavation on the adjacent buildings is relatively small, while the reverse method requires in-situ reinforced concrete after excavation, and drainage should be carried out before construction. For the areas with high groundwater level, poor soil quality and complex surrounding environment, the caisson construction method is generally used to construct the pipe jacking well.

In the caisson construction method in the prior art, the sinking speed of the caisson is slow, the surrounding soil body will be pulled down and deformed during the sinking process of the caisson, and flow soil and sand will also be generated in some places, which will affect the foundation stability of the surrounding adjacent buildings. greater impact. In addition, the reinforced concrete caisson and other related supporting structures are not reusable, and the cost and waste of temporary support are high. On the other hand, in some projects, steel sheet pile support is also used directly as a pipe jacking well. Steel sheet pile support has the advantage of high construction efficiency, but the stiffness of steel sheet piles is small. When used as the starting well for pipe jacking, if the jacking force exceeds If the steel sheet pile is too large, the steel sheet pile may be deformed greatly. If the deformation is too large, the upper steel support will fall off, and there will be a greater construction risk.

In conclusion, there is a need for a construction method that can not only take advantage of the convenience and high efficiency of steel sheet pile construction, but also take advantage of the advantages of high stiffness of reinforced concrete caisson, high sidewall bearing capacity, good integrity and high safety. The temporary support used can be reused many times to maximize efficiency, economy and safety, so as to effectively shorten the construction period and reduce the project cost.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems, the purpose of the present invention is to provide a pipe jacking well structure, which can not only play the characteristics of convenient construction and high efficiency of steel sheet piles, but also play a role in the high rigidity of the reinforced concrete caisson and the high bearing capacity of the side walls. It has the advantages of good integrity and high safety, and can be reused at the same time, maximizing efficiency, economy and safety, so as to effectively shorten the construction period and reduce the project cost; another purpose of the present invention is to provide a top Construction method of tube well structure.

In order to achieve the above object, the present invention provides a pipe jacking well structure, comprising a plurality of steel sheet piles for vertical and detachable insertion in the soil, and the plurality of the steel sheet piles encloses a hollow construction space;

At least one layer of purlin structure is fixed on the inner side of the steel sheet pile in the construction space;

The purlin structure includes a plurality of purlins fixed on the inner side of the steel sheet pile, the plurality of purlins are fixed in sequence and connected end to end, the bottom of each purlin is provided with a support member, and the adjacent purlins are provided with support members. There are corner braces connected between the purlins;

The lower part of the steel sheet pile is provided with a caisson body.

As a preferred solution, the purlin is provided with four, and the four purlins are formed into a square shape;

The purlin is I-beam.

As a preferred solution, the support is a steel corbel;

The steel corbel includes a support plate arranged horizontally and fixedly connected with the bottom of the purlin, and the bottom of the support plate is vertically fixed with a triangular rib;

The support plate and the rib are arranged in a T-shape.

As a preferred solution, medium-coarse sand is filled between the caisson body and the inner wall of the steel sheet pile.

As a preferred solution, the bottom of the caisson body is provided with a caisson bottom plate, and the bottom of the caisson bottom plate is provided with bottom sealing concrete;

The caisson body is provided with a pipe jacking rear seat wall.

A construction method for a pipe jacking well structure, comprising the following steps:

S1, a plurality of rust-proof treated steel sheet piles are piled, and a plurality of the steel sheet piles are enclosed into a construction space;

S2, remove the earthwork of the first depth of the construction space, and set a purlin structure on the steel sheet pile;

First, a support is provided, and a plurality of purlins arranged in a ring shape are arranged on the upper part of the support; secondly, a gusset is fixedly arranged on the adjacent said purlin;

S3, continue to remove the earthwork of the second depth of the construction space downward, and set the purlin structure;

S4, continue to remove the earthwork of the third depth of the construction space downward, and set multi-section caisson in turn;

S5, after the construction of all the well walls is completed and the foundation pit has been excavated to the design elevation, the bottom sealing concrete is poured, and the caisson floor is set on the bottom sealing concrete after removing the accumulated water.

S6, after the pipe jacking operation, backfill the foundation pit and remove the steel purlins, gussets and steel sheet piles layer by layer.

As a preferred solution, in the step 1, before the steel sheet pile is piled, it should be positioned on the site according to the requirements of the design drawings, and a guide frame should be set up, and the lock opening should be filled with waterproof material;

The verticality deviation of the steel sheet piles should not be greater than 1/100.

As a preferred solution, the first depth is 1 meter, the second depth is 4 meters, and the third depth is 3 meters.

As a preferred solution, in the step S4, the pouring steps of the caisson body are: preparing the bearing pad of the edge foot; binding the steel bars of the caisson and encapsulating the formwork; pouring concrete after the formwork is encapsulated, and waiting for the concrete strength to reach 75% of the design strength Afterwards, the caisson body can be sunk.

As a preferred solution, the subsidence method of the caisson body adopts the method of extruding the soil and excavating the soil evenly and symmetrically, so as to ensure the balanced, uniform and stable subsidence of the caisson;

Before sinking, medium-coarse sand, which sinks synchronously with the caisson, is set between the shaft wall of the caisson body and the steel sheet pile wall.

Compared with the prior art, the beneficial effects of the present invention are:

The pipe jacking well structure of the present invention uses steel sheet piles as support in the caisson construction method, adopts a plurality of steel sheet piles vertically inserted in the soil to form a hollow construction space, and is fixedly arranged on the inner side of the steel sheet piles in the construction space. There is at least one layer of purlin structure; the purlin structure includes a plurality of purlins fixed on the inner side of the steel sheet pile, the plurality of purlins are fixed in sequence and connected end to end, the bottom of each purlin is provided with a support, and the adjacent purlins are A gusset is connected between the purlins; the lower part of the steel sheet pile is provided with a caisson body. After the construction of the caisson is completed, the steel purlins, gussets and steel sheet piles can be removed in sequence, and the steel sheet piles can be recycled and reused. Steel sheet piles are used as caisson support, and the steel sheet piles are convenient and quick in construction to form support within the upper 5m to 6m range of the foundation pit of the pipe jacking well. A support structure is formed within a range of 5m for the pipe jacking well structure operation, so as to maximize the respective advantages of steel sheet piles and caisson construction and form complementary advantages.

The construction method of the pipe jacking shaft structure of the present invention can not only take advantage of the characteristics of convenient construction and high efficiency of steel sheet piles, but also take advantage of the advantages of high rigidity of reinforced concrete caisson, high side wall bearing capacity, good integrity and high safety. And the purlin structure can be recycled and reused to maximize efficiency, economy and safety, so as to effectively shorten the construction period and reduce the project cost.

Description of drawings

1 is a schematic structural diagram of a pipe jacking well structure in an embodiment of the present invention;

Fig. 2 is the top view of Fig. 1;

Figure 3 is a schematic structural diagram of the purlin structure.

In the figure, 1, steel sheet pile; 2, steel corbel; 21, support plate; 22, rib; 3, steel purlin; 4, steel angle brace; 5, caisson body; 6, medium and coarse sand; 7, Back cover concrete; 8. caisson floor; 9. pipe jacking rear seat wall.

Detailed ways

The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

In the description of the present invention, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. are based on those shown in the accompanying drawings The orientation or positional relationship is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. It should be understood that the terms "first", "second", etc. are used in the present invention to describe various information, but these information should not be limited to these terms, which are only used to distinguish the same type of information from each other. For example, "first" information may also be referred to as "second" information, and similarly, "second" information may also be referred to as "first" information, without departing from the scope of the present invention.

The preferred embodiment of the pipe jacking well structure of the present invention, as shown in FIG. 1 , includes a plurality of steel sheet piles 1 for vertical and detachable insertion in the soil, and the plurality of steel sheet piles 1 encloses a hollow construction space; the steel sheet piles 1 Specifically, it is a straight rod-shaped structure, and its cross section can be square or semi-circular. At least one layer of purlin structure is fixed inside the steel sheet pile 1 in the construction space; the purlin structure is used to support and maintain the steel plate. Pile 1.

Specifically, the surrounding purlin structure includes a plurality of surrounding purlins 3 fixed on the inner side of the steel sheet pile 1, the plurality of surrounding purlins 3 are fixed in sequence and connected end to end, each surrounding purlin 3 and the steel sheet pile 1 are welded and fixed, and each surrounding purlin The bottom of 3 is provided with support pieces, which are fixedly connected with the steel sheet pile 1 and the purlin at the same time, and the support piece is made of steel, and the support piece is fixedly connected with the steel sheet pile 1 and the steel purlin by welding. Angle braces 4 are connected between adjacent purlins 3 to further improve the supporting strength of the purlin structure;

In the pipe jacking well structure of the present invention, the purlins 3, the angle braces 4 and the steel sheet piles 1 can be removed in sequence after the caisson construction is completed, and the steel sheet piles 1 can be recycled and reused. The steel sheet pile 1 is used as the support for the caisson, and the steel sheet pile 1 is used for convenient and fast construction to form support within the upper 5m to 6m range of the foundation pit of the pipe jacking well, and then take advantage of the high stiffness of the caisson. The supporting structure is formed within the range of 4m to 5m for the pipe jacking structure operation, so as to maximize the respective advantages of the steel sheet pile 1 and the caisson construction and form complementary advantages.

The pipe jacking shaft structure of the present invention can not only take advantage of the characteristics of convenient construction and high efficiency of the steel sheet pile 1, but also take advantage of the advantages of high rigidity of the reinforced concrete caisson body, high side wall bearing capacity, good integrity and high safety. And the purlin 3 structure can be recycled and reused to maximize efficiency, economy and safety, so as to effectively shorten the construction period and reduce the project cost.

Wherein, in the embodiment of the present application, there are four surrounding purlins 3, the surrounding purlins 3 are specifically I-beams, the four surrounding purlins 3 are enclosed in a square shape, the gusset 4 is a plate-like structure, and the gusset 4 is also four They are respectively inclined and arranged on the four corners of the purlin structure, and are used to connect two adjacent purlins 3 .

Further, the support 2 is a steel corbel. Specifically, the steel corbel includes a supporting plate 21 that is arranged horizontally and is fixedly connected to the bottom of the purlin 3. The supporting plate 21 and the bottom of the purlin 4 can be fixed by welding or by bolts, etc. The fasteners are fixedly connected, the bottom of the support plate 21 is vertically fixed with a triangular rib plate 22, and the support plate 21 and the rib plate 22 are arranged in a T-shape. The rib plate 22 is used to support the support plate 21 to improve the fixing effect of the support plate 21 .

The medium-coarse sand is filled between the caisson body 5 and the inner wall of the steel sheet pile 1 , and the medium-coarse sand sinks synchronously with the caisson body 5 to facilitate the construction of the caisson body 5 .

Wherein, the bottom of the caisson body 5 of the present application is provided with a caisson bottom plate 8, and the bottom of the caisson bottom plate 8 is provided with a bottom sealing concrete 7;

During the specific construction, after the sinking of the first section of the caisson body 5 is completed, the next section of the caisson body 5 is constructed according to the same steps. After the construction of all the caisson bodies 5 is completed and the foundation pit has been excavated to the design elevation, the bottom sealing concrete 7 is poured in time. The bottom sealing concrete 7 can be selected according to the construction method of the caisson. After the bottom sealing concrete 7 is poured, the accumulated water in the caisson pit is drained, the caisson bottom plate 8 is constructed, and the excavation of the pipe jacking well is completed. After the construction of the caisson floor 8 is completed, the rear seat wall 9 of the pipe jacking is constructed, the pipe jacking equipment is installed and the pipe jacking operation is carried out. Purlins, gussets and other horizontal support structures. After the foundation pit is backfilled as required, the steel sheet pile 1 shall be recovered, and the hole in the pile position shall be filled with medium sand or grouting.

The embodiment of the construction method of the pipe jacking well structure of the present invention comprises the following steps:

S1 , driving a plurality of rust-proof treated steel sheet piles 1 to form a construction space.

Before the construction of the steel sheet pile 1, the line should be set out on the site according to the requirements of the design drawings to ensure that the construction space enclosed by the steel sheet pile 1 can meet the requirements of the subsequent construction of the caisson body 5. Specific can be coated with epoxy coal tar paint protection. The lock should be filled with waterproof material. A guide frame should be set before the steel sheet pile 1 is driven to ensure the accuracy of the plane size. The verticality deviation should not be greater than 1/100 when driving the pile, and the lock should be tight.

S2, remove the earthwork of the first depth in the construction space, and set a purlin structure on the steel sheet pile 1;

First, a support member 21 is provided, and a plurality of purlins 3 arranged in a ring shape are arranged on the upper part of the support member 21 ;

After the construction of the steel sheet pile 1 is completed, earthwork excavation shall be carried out. When the excavation reaches a depth of about 1 meter, the first surrounding purlin structure shall be constructed. Before constructing the purlin 3, construct the steel corbel first. The steel corbel includes a support plate 21 and a rib plate 22. The support plate 21 and the rib plate 22 are welded and fixed in a T-shape. As shown in FIG. 3, the support plate 21 and the rib plate 22 are both It needs to be welded with the steel sheet pile 1, and the quality level of the welding seam is level 3. The next step of construction can be carried out after the appearance inspection and acceptance. After the construction of the horizontal supporting structures such as the first purlin 3 and the angle brace 4 is completed, continue to excavate downward. When the excavation reaches a depth of about 4 meters, construct the second purlin structure, which is the same as the first purlin structure. The construction method of each purlin structure is the same.

S3, continue to remove the earthwork of the third depth in the construction space downward, and set the multi-section caisson body 5 in sequence. The construction of the caisson body 5 can reasonably choose to use drainage or undrained subsidence according to the specific geological conditions. When there is groundwater within the subsidence depth of the caisson body 5 and there is silt or silty sand layer in the soil layer, or there are existing buildings or structures near the caisson, it is recommended to use undrained subsidence.

Specifically, the first section of the shaft wall body 5 includes a total of about 2.5 m in height of the blade feet. After the cushion facilities for the blade feet are prepared, the caisson steel bars are bound and the formwork is packaged. After the formwork is packaged, concrete is poured, and the sinking of the caisson body 5 is started after the concrete strength of the caisson body 5 in this section reaches 75% of the design strength. When the caisson body 5 sinks, it is advisable to use extruding soil to sink, and the cutting edge should not be hollowed out at will. The excavation should be uniform and symmetrical, and effective measures should be taken to maintain the balance, uniform and stable sinking of the caisson body. Before the caisson body 5 sinks, medium-coarse sand 6 should be used to fill the space between the caisson shaft wall and the wall of the steel sheet pile 1 , and the medium-coarse sand 6 sinks synchronously with the well wall 5 . After the sinking of the first section of the caisson body 5 is completed, the next section of the caisson body 5 is constructed according to the same method.

S4, after the construction of all the well walls is completed and the foundation pit has been excavated to the design elevation, pour the bottom sealing concrete 7, and the bottom sealing concrete 7 can be selected according to the construction method of the caisson body 5. A caisson floor 8 is arranged on the back cover concrete 7 . Finally, construct the pipe jacking rear seat wall 9 and install the pipe jacking equipment and carry out the pipe jacking operation.

S5, after the pipe jacking operation, backfill the foundation pit and remove the purlins 3, the angle braces 4 and the steel sheet piles 1 layer by layer.

After the pipe jacking operation is completed, the corresponding inspection wells shall be constructed according to the needs, the foundation pit shall be backfilled, and the horizontal supporting structures such as steel purlins 3 and angle braces 4 shall be removed layer by layer. After the foundation pit is backfilled as required, the steel sheet piles 11 can be recovered, and the holes in the pile positions of the steel sheet piles 11 are filled with medium sand or grouting.

The construction method of the pipe jacking shaft structure of the present invention can not only take advantage of the advantages of convenient construction and high efficiency of the steel sheet pile 1, but also take advantage of the advantages of high rigidity of the reinforced concrete caisson body, high side wall bearing capacity, good integrity and high safety. The steel sheet pile 1 and the surrounding purlin structure can be recycled and reused to maximize efficiency, economy and safety, so as to effectively shorten the construction period and reduce the project cost.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principle of the present invention, several improvements and replacements can be made. These improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims (10)

1. A pipe jacking well structure is characterized by comprising a plurality of steel plate piles which are vertically and detachably inserted in soil, wherein a hollow construction space is defined by the steel plate piles;

at least one layer of enclosing purlin structure is fixedly arranged on the inner side of the steel sheet pile in the construction space;

the enclosing purlin structure comprises a plurality of enclosing purlins fixedly arranged on the inner side surfaces of the steel sheet piles, the plurality of enclosing purlins are sequentially fixed and connected end to end, the bottom of each enclosing purlin is provided with a support piece, and a corner brace is connected between every two adjacent enclosing purlins;

and the lower part of the steel sheet pile is provided with an open caisson body.

2. The pipe jacking well structure of claim 1, wherein the purlins are four, and four purlins enclose a square;

the enclosing purlin is made of I-shaped steel.

3. The pipe jacking well structure of claim 2, wherein said support member is a steel corbel;

the steel bracket comprises a supporting plate which is horizontally arranged and fixedly connected with the bottom of the enclosing purlin, and a triangular rib plate is vertically and fixedly arranged at the bottom of the supporting plate;

The supporting plate and the rib plate are arranged in a T shape.

4. The push bench structure of claim 1, wherein medium grit is filled between said caisson body and the inner wall of said steel sheet pile.

5. The push bench structure of claim 1, wherein a bottom plate of the open caisson is arranged at the bottom of the open caisson body, and bottom sealing concrete is arranged at the bottom of the open caisson plate;

and a jacking pipe rear seat wall is arranged on the open caisson body.

6. A pipe jacking well structure construction method according to any one of claims 1 to 5, comprising the steps of:

s1, piling a plurality of steel sheet piles subjected to rust prevention treatment, wherein the plurality of steel sheet piles enclose a construction space;

s2, removing earthwork of the first depth of the construction space, and arranging a surrounding purlin structure on the steel sheet pile;

firstly, arranging a support piece, wherein the upper part of the support piece is provided with a plurality of annularly arranged purlins; secondly, angle braces are fixedly arranged on the adjacent surrounding purlins;

s3, continuously removing earthwork of a second depth of the construction space downwards, and setting a surrounding purlin structure;

s4, continuously removing earthwork at a third depth of the construction space downwards, and sequentially arranging a plurality of sections of open caisson;

S5, after all well wall constructions are completed and the foundation pit is excavated to the designed elevation, pouring bottom sealing concrete, and setting a sunk well bottom plate on the bottom sealing concrete after removing accumulated water.

And S6, backfilling the foundation pit and removing the steel surrounding purlin, the angle brace and the steel sheet pile layer by layer after pipe jacking operation.

7. The pipe jacking well structure construction method according to claim 6, wherein in the step 1, before the steel sheet pile is sunk, the steel sheet pile is positioned by paying off on site according to the design drawing requirements, a guide frame is arranged, and waterproof materials are filled in the locking opening;

the verticality deviation of the steel plate pile sinking is not more than 1/100.

8. The pipe jacking well structure construction method according to claim 6, wherein the first depth is 1 m, the second depth is 4 m, and the third depth is 3 m.

9. The pipe jacking well structure construction method according to claim 6, wherein in the step S4, the step of pouring the caisson body is as follows: preparing a bearing pad of the blade foot; binding open caisson reinforcing steel bars and packaging a template; and pouring concrete after the template is packaged, and sinking the open caisson body after the strength of the concrete reaches 75% of the design strength.

10. The pipe jacking well structure construction method according to claim 9, wherein the sinking method of the sinking well body adopts soil squeezing sinking, the soil digging is uniform and symmetrical, and the balanced, uniform and stable sinking of the sinking well is ensured;

Before sinking, medium coarse sand which sinks synchronously along with the open caisson is arranged between the well wall of the open caisson body and the steel sheet pile wall.

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