CN207261017U - Tunnel form prestressed pipe curtain system - Google Patents

Abstract

A prestressed pipe curtain system in the form of a tunnel. The pipe curtain system is composed of several prefabricated concrete beams, prefabricated steel units, a concrete cast-in-place section, several transverse prestressed tendons and longitudinal prestressed tendons. The prefabricated concrete beams pass through Locking and joint grouting are connected, and the whole is formed by tensioning the transverse prestressing tendons and the longitudinal prestressing tendons; the prefabricated steel unit is used as the construction platform of the transverse prestressing tendons to apply circumferential or transverse prestressing for several prefabricated concrete beams ; The concrete cast-in-place section is located at the bottom of the pipe curtain system. The prefabricated concrete beams and corner steel units used in the pipe curtain system can be standardized in the factory, which can not only ensure the structure has good mechanical performance, but also has the advantages of simple structure, fast construction speed, high overall rigidity, cost saving and It has a broad application prospect in the construction of underground structures, especially in the construction of municipal engineering.

Description

Tunnel form prestressed pipe curtain system

technical field

The utility model belongs to the technical field of civil engineering, and more specifically relates to a tunnel form prestressed pipe curtain system and construction technology.

Background technique

Pipe curtain construction technology is a non-excavation technology for constructing underground structures, and it is mostly used in underground buildings that cross roads, railways, structures, airports, etc. Pipe curtain construction technology, by excavating the departure well and working well at both ends of the underground structure, and adopting the method of jacking prefabricated components, an annular curtain structure is formed underground to bear the surrounding load and prevent water, and then excavate and build underground structure. As a kind of trenchless technology, compared with construction technologies such as pipe jacking and shield tunneling, pipe curtain construction technology has smaller requirements for construction space and less impact on the surrounding environment. There are successful cases in various countries in the world.

After more than 40 years of engineering practice, a variety of different pipe curtain construction technologies have been developed, including ESA (Endless Self-advancing) construction method, FJ (Front Jacking Method) construction method, RBJ (Roof-Box Jacking Method) construction method, R&C (Roof&Culvert ) construction method, New Tubular Roof Method (NTR construction method for short), etc. Among them, for the ESA construction method, FJ construction method, RBJ construction method and R&C construction method, the jacked pipe curtain is only used as a temporary structure to provide a certain support and waterproof function for the later box culvert jacking. The difference lies in the jacking of the box culvert different ways. The new pipe curtain method, as an improvement of the traditional pipe curtain method, uses large-diameter steel pipes (generally more than 1800mm in diameter) for jacking, and retains them as a permanent structure. Outline of the structure. However, the above-mentioned various pipe curtain construction techniques are cumbersome, requiring jacking of the pipe curtain and the box culvert, prolonging the construction period and increasing the cost; in addition, due to the existence of the upper pipe curtain, the elevation of the box culvert must be reduced accordingly, increasing the The depth of the foundation pit of the working well increases the difficulty and risk of construction.

Chinese patent CN105464675A discloses a new type of surface contact pipe curtain system and its construction method. The pipe curtain system is used as the advance support structure of the tunnel, which is composed of rectangular steel pipes or similar rectangular steel pipes with at least two contact planes. The steel pipes are in surface contact; the steel pipes include at least two contact planes, which respectively fit seamlessly with the contact planes of adjacent steel pipes; the sizes of the two contact planes in contact with each other are adapted to each other; Two long edges of a contact plane are respectively welded with a slideway, and two adjacent steel pipes are fixedly connected through the slideway. Among them, the pipe curtain system cannot be used as a permanent structure, and the steel pipes are only connected by welding slides. Compared with the structure formed by prestressed tension, the strength is far from guaranteed.

Chinese patent CN102518443A discloses a new method for special combination construction of ultra-shallow soil-covered special-shaped passages, which is used to solve the problem that when the top soil layer of the underground tunnel construction surface is thin, the soil layer collapses due to underground excavation, and the construction can no longer be carried out. , by excavating the top of the construction surface of the underground tunnel in the ultra-shallow soil layer with a small module square roadheader, pushing the square steel pipes section by section to form a horizontally arranged pipe curtain, and then placing a reinforced concrete box behind the large-section excavator Culvert replacement pipe curtain construction. It still needs box culverts, which cannot solve the above-mentioned problems caused accordingly.

Chinese patent CN205172598U discloses a pipe curtain jet grouting pile support structure, including several pipe curtain steel pipes, at least one horizontal jet grouting pile is arranged between every two pipe curtain steel pipes, and the pipe curtain steel pipe and the horizontal jet jet pile The edges are in close contact, and the pipe-curtain steel pipe and the horizontal jet grouting pile are combined to form a high-rigidity common support force system. Setting up horizontal jet grouting piles is difficult to construct and will bring many new problems. As a permanent structure, it is difficult to guarantee the strength and accuracy requirements.

Utility model content

The purpose of this utility model is to propose a new type of pipe curtain construction technology, that is, a tunnel form prestressed pipe curtain system, to solve the above problems and risks. The tunnel form prestressed pipe curtain method is a construction site where four corner steel units are used as prestressed tendons. Through prestressing, several individual components around the pipe curtain are tightly bound together to control the deformation of the pipe curtain. It is a construction method that improves the integrity of the pipe curtain, thereby achieving higher safety and economy. The system adopts the post-tensioning non-bonded full prestressing system, and the reliable connection between the components is formed through crack grouting and prestressing. The waterproof requirements are realized through locking and grouting between the components. Cast-in-place concrete is used for the corner steel units to ensure the stiffness of the joints. The cast-in-place closed section of the final construction solves the problem of inability to close the dragon caused by construction errors.

According to above-mentioned purpose, the technical scheme that the utility model adopts is:

A tunnel form prestressed pipe curtain system, said pipe curtain system is composed of several prefabricated concrete beams 1, prefabricated steel units 2, a concrete cast-in-place section 3, several transverse prestressed tendons 4 and longitudinal prestressed tendons 5, said Some prefabricated concrete beams 1 are connected by locks and crack grouting, and form a whole by stretching the transverse prestressed tendons 4 and the longitudinal prestressed tendons 5; The prefabricated concrete beam 1 applies hoop or transverse prestress; the concrete cast-in-place section 3 is located at the bottom of the pipe curtain system, and is the cast-in-place closure section of the pipe curtain system.

Further, the pipe curtain system is a circular prestressed pipe curtain system, and all components on the cross section are firmly tied together by hoop prestress.

Further, the pipe curtain system is a box-type prestressed pipe curtain system, and the various components are connected together by longitudinal and transverse prestressed tendons, and the tendons make each contact point between every two members in a compressed state , forming a fully prestressed member structure.

Further, the prefabricated steel unit 2 forms a rigid node by placing a reinforcement cage and cast-in-place concrete.

Further, the prefabricated steel unit 2 is located at the uppermost end point of the circular prestressed pipe curtain system.

Further, there are four prefabricated steel units 2, and the four prefabricated steel units 2 are placed at four corners of the box-type prestressed pipe curtain system.

Further, the prefabricated concrete beam 1 and the prefabricated steel unit 2 are provided with reserved holes 6 for transverse prestressed tendons, and the prefabricated concrete beam 1 is provided with reserved holes 7 for longitudinal prestressed tendons; The reserved holes 6 for stress tendons are used to place transverse prestressed tendons 4 , and the reserved holes 7 for longitudinal prestressed tendons are used to place longitudinal prestressed tendons 5 .

Further, the reserved holes 6 for the transverse prestressed tendons are arranged in two rows in the tension and compression zone at the edge of the precast concrete beam 1; and/or the reserved holes 7 for the longitudinal prestressed tendons are arranged layout around.

Further, the transverse prestressed tendons 4 are unbonded prestressed tendons.

The beneficial effects of the utility model are:

1. Does not affect the normal traffic on the upper road surface

Before the prefabricated concrete beam is jacked, the utility model first jacks the tool steel pipe with a knife edge to cut the soil, so that the surrounding environment is effectively controlled without disturbing the normal use of the surrounding soil, and then the beam and the steel pipe are The jacking replacement of the project controls the settlement and greatly reduces the impact on the upper ground road.

Due to the use of prestress, the utility model effectively controls the overall deflection of the pipe curtain, thereby ensuring the normal use of the upper road surface.

Because the utility model adopts the replacement propulsion method of the prefabricated concrete beam, even if the soil condition is bad, including gravel, pebbles or obstacles, the utility model can ensure higher propulsion precision.

2. High engineering quality

Because the prefabricated concrete beam and the prefabricated steel unit are prefabricated in the factory, the utility model can strictly control the quality of the components through assembly line operation, so it has sufficient quality and reliability guarantee.

Because the main material of the structure is high-strength concrete, the utility model has excellent corrosion resistance and durability.

3. Lower cost and shorter construction period

Because the prestressed pipe curtain in the tunnel form directly serves as a part of the permanent structure, the utility model reduces the additional engineering procedures and costs caused by the temporary construction, such as the cost of the box culvert required by the traditional pipe curtain method.

Due to the reduced structure size of the utility model, the elevation of the overall project is improved, and the excavation volume of earthwork is reduced, so the overall construction period and engineering cost are reduced.

4. Higher excavation safety

In the utility model, after the tunnel form prestressed pipe curtain is formed, the overall structure has been formed, and there is basically no risk when excavating the soil inside the tunnel.

5. High degree of mechanization

The utility model saves a lot of labor force in a series of mechanized work from propulsion to excavation inside the tunnel, and also makes project management more efficient and convenient.

The tunnel form prestressed pipe curtain method proposed by the utility model adopts a large number of prefabricated components standardized in the factory, which can ensure good mechanical performance of the structure, and has the advantages of simple structure, fast construction speed, large overall rigidity, cost saving and construction period It has broad application prospects in underground structure construction, especially municipal engineering construction, and is in line with the development strategy of green buildings and industrialized buildings in China.

Description of drawings

Figure 1 is the overall effect diagram of the tunnel form prestressed pipe curtain system;

Figure 2 is a cross-sectional view of the circular prestressed pipe curtain system;

Figure 3 is a cross-sectional view of the box-type prestressed pipe curtain system;

Fig. 4 is a schematic diagram of locking between prefabricated concrete beams;

Figure 5 is a detailed schematic diagram of the prefabricated steel unit;

Reference signs in the figure:

1- prefabricated concrete beam, 2- prefabricated steel unit, 3- cast-in-place concrete section, 4- transverse prestressed tendon, 5- longitudinal prestressed tendon, 6- reserved hole for transverse prestressed tendon, 7- longitudinal prestressed tendon Leave holes.

Detailed ways

The specific implementation of the present utility model will be described in further detail below through the description of the best embodiment.

As shown in Figure 1, the utility model tunnel form prestressed pipe curtain system is composed of several prefabricated concrete beams 1, prefabricated steel units 2, a concrete cast-in-place section 3, several transverse prestressed tendons 4 and longitudinal prestressed tendons 5, The plurality of prefabricated concrete beams 1 are connected by locks and crack grouting, and form a whole by stretching the transverse prestressed tendons 4 and the longitudinal prestressed tendons 5; the prefabricated steel unit 2 serves as a construction platform for the transverse prestressed tendons 4, Apply hoop or transverse prestress to several prefabricated concrete beams 1; the concrete cast-in-place section 3 is located at the bottom of the pipe curtain system, and is the cast-in-place closure section of the pipe curtain system. The prefabricated steel unit 2 forms a rigid node by placing a reinforcement cage and cast-in-place concrete. Both the prefabricated concrete beam 1 and the prefabricated steel unit 2 are provided with reserved holes 6 for transverse prestressing tendons, and the precast concrete beam 1 is provided with reserved holes 7 for longitudinal prestressing tendons. The reserved holes 6 for the transverse prestressed tendons are arranged in two rows in the tension and compression zone at the edge of the precast concrete beam 1; and/or the reserved holes 7 for the longitudinal prestressed tendons are arranged around the precast concrete beam 1 . The transverse prestressed tendons 4 are unbonded prestressed tendons.

As shown in Fig. 2, when the pipe curtain system is a circular prestressed pipe curtain system, all components on the cross section are firmly tied together by hoop prestress. The prefabricated steel unit 2 is located at the uppermost end point of the circular prestressed pipe curtain system. The concrete cast-in-place section 3 is located at the bottommost end point of the circular prestressed pipe curtain junction. In this specific embodiment, there is only one prefabricated steel unit 2, which is located at the uppermost end point.

As shown in Figure 3, when the pipe curtain system is a box-type prestressed pipe curtain system, the various components are connected together by longitudinal and transverse prestressed tendons, and these prestressed tendons make the gap between every two members Each point of contact is under compression, forming a fully prestressed member structure that works together. At this time, the structure has four prefabricated steel units 2, and the four prefabricated steel units 2 are placed at four corners of the box-type prestressed pipe curtain system.

Figure 4 is a schematic diagram of the locking between precast concrete beams; the figure shows the connection details, and the left and right precast concrete beams 1 are connected by locking, and the internal grouting is enough. The two opposite surfaces of the precast concrete beam 1 are provided with grooves, and the latches are located in the grooves.

As shown in Figure 5, it is a schematic diagram of the detailed structure of the prefabricated steel unit; the prefabricated steel unit 2 is a roughly rectangular structure, and at all corresponding parts that are in contact with the prefabricated concrete beam 1, there are reserved holes 6 for transverse prestressing tendons, which are used for Make the transverse prestressing tendon 4 pass through the prefabricated rigid unit 2 and the prefabricated concrete beam 1 .

The construction method of the tunnel form prestressed pipe curtain system is as follows:

First, excavate the departure shaft and the receiving shaft on both sides of the building that need to pass through the pipe curtain, and then carry out the construction of the three-part tunnel-shaped prestressed pipe curtain system in the order of the upper part first, then the sides on both sides, and finally the bottom.

The construction process of the above three parts of the top, side and bottom is roughly the same, mainly including precast concrete beam jacking and prestressed tension. Among them, during the construction of the base plate, a closed section needs to be cast in place to complete the closure of the entire box-shaped tube curtain. The following will take floor construction as an example to explain in detail.

A. Tool steel pipe jacking

After the departure shaft and receiving shaft have been excavated, and the propulsion frame and thruster have been installed, the tool steel pipe, guided by the tunneling machine installed at the head, is pushed to the design position of the precast concrete beam in sections.

An important function of the tool steel pipe is to transport the soil at the position of the precast concrete beam through the steel pipe during the pushing process, that is, to replace the soil in this part with the tool steel pipe, and to bear its original force transmission function, effectively controlling impact of construction on the surrounding environment.

B. Replacement advancement of precast concrete beams

After the tool steel pipe is pushed into place, push the precast concrete beam at the same position to replace the previously pushed tool steel pipe. After the top of the precast concrete beam is pushed into the soil, longitudinal prestress is applied between each section of the precast concrete beam, and the whole precast concrete beam is connected as a whole through the prestressed connection between the sections to become a fully prestressed beam. During the jacking process of precast concrete beams, tool steel pipes are recovered in the receiving shaft and used for jacking of precast concrete beams at adjacent positions.

C. Prefabricated steel unit jacking

After the entire row of precast concrete beams are pushed into place, the prefabricated steel units are pushed in parallel at the positions adjacent to the precast concrete beams at both ends. The difference from the previous tool steel pipe is that the prefabricated steel unit will not be replaced after being jacked in place, but will be reinforced inside and used as a formwork for cast-in-place concrete. Not taken out in the overall structure. Both prefabricated steel units and prefabricated concrete beams are jacked in sections, and the joints are connected by on-site welding.

D. Applying transverse prestress and joint grouting

Before penetrating the prestressed tendons, clean the cracks between the components and wash away the residual soil inside and outside the precast concrete beam lock with running water. This is very important for the quality of the entire project. If there is residual soil inside, it will cause cracks to fill If the mortar is not dense, it will seriously affect the service life of the prestressed tendons.

Then in the prefabricated steel unit, the unbonded prestressed tendons are penetrated transversely perpendicular to the precast concrete beams, and the prestressed tendons are arranged in two rows at the edge of the precast concrete beams in tension and compression. After all the prestressed tendons are penetrated, mortar is filled in the cracks to play the role of waterproofing and structural stress.

Finally, the transverse prestressed tendon is stretched in the prefabricated steel unit, and the transverse prestress is applied to the pipe curtain.

E. Cast-in-place concrete construction

Both the top and side parts adopt the above construction process, and part of the closing section needs to be cast-in-place at the bottom plate. A unit position is reserved at the bottom for cast-in-place closure during the process of pushing the tool steel pipe, and the reserved section uses temporary steel plates as the covering soil support. Then guide and push into the bound steel cage, penetrate the transverse prestressed tendons, and fill the part with cast-in-place concrete with high fluidity.

F. Final excavation and completion

After the construction of the pipe curtain on the upper top, both sides and the bottom is completed, the interior of the prefabricated steel unit is reinforced, and the concrete with high fluidity is poured in place to fill it. So far, the entire construction of the tunnel-shaped prestressed pipe curtain system has been completed. After completion, when the concrete reaches the design strength, the soil can be excavated inside, and the inside of the pipe curtain can be constructed, and finally the end of the pipe curtain can be blocked.

The above is just an explanation of the construction method by taking the construction of the box structure as an example. The construction method of the circular structure is still: steel unit jacking, prefabricated concrete beam jacking, vertical and horizontal prestressed tension, and finally cast-in-place closed section, and box structure The construction methods are similar, so they will not be repeated here.

The above is only an exemplary description of the utility model. Obviously, the specific implementation of the utility model is not limited by the above-mentioned method. As long as the method concept and technical solution of the utility model are adopted, any skilled person Various improvements, changes or replacements that can be easily thought of, or directly applied to other occasions without improvement, all fall within the protection scope of the present utility model.

Claims (9)

1. A tunnel form prestressed pipe curtain system, characterized in that the pipe curtain system consists of some prefabricated concrete beams (1), prefabricated steel units (2), a concrete cast-in-place section (3), some transverse prestressed tendons (4) and longitudinal prestressed tendons (5), the prefabricated concrete beams (1) are connected by locks and joint grouting, and the transverse prestressed tendons (4) and longitudinal prestressed tendons (5) are stretched ) to form a whole; the prefabricated steel unit (2) is used as a construction platform for the transverse prestressed tendon (4), and applies hoop or transverse prestress for several prefabricated concrete beams (1); the concrete cast-in-place section (3) is located at The bottom of the pipe curtain system is the cast-in-place closing section of the pipe curtain system. 2. The tunnel form prestressed pipe curtain system as claimed in claim 1, characterized in that: the pipe curtain system is a circular prestressed pipe curtain system, and all components on the cross section are firmly fixed by circumferential prestress Chained together. 3. The tunnel-type prestressed pipe curtain system according to claim 1, characterized in that: the pipe curtain system is a box-type prestressed pipe curtain system, and the various components are connected together by longitudinal and transverse prestressed tendons. Form a fully prestressed member structure. 4. The tunnel form prestressed pipe curtain system according to claim 2 or 3, characterized in that: the prefabricated steel unit (2) forms rigid joints by placing reinforcement cages and cast-in-place concrete. 5. The tunnel form prestressed pipe curtain system according to claim 2, characterized in that: the prefabricated steel unit (2) is located at the uppermost end point of the circular prestressed pipe curtain system. 6. The tunnel form prestressed pipe curtain system as claimed in claim 3, characterized in that: said box type prestressed pipe curtain system has four said prefabricated steel units (2), four said prefabricated steel units (2) Placed at the four corners of the box-type prestressed pipe curtain system. 7. The tunnel form prestressed pipe curtain system according to claim 2 or 3, characterized in that: the prefabricated concrete beam (1) and the prefabricated steel unit (2) are provided with transverse prestressed reinforcement hole (6), the precast concrete beam (1) is provided with a longitudinal prestressed tendon reserved hole (7); the transverse prestressed tendon reserved hole (6) is used to place the transverse prestressed tendon (4), the The reserved holes (7) for the longitudinal prestressed tendons are used for placing the longitudinal prestressed tendons (5). 8. The tunnel form prestressed pipe curtain system as claimed in claim 2 or 3, characterized in that: the tension and compression division of the reserved hole (6) of the transverse prestressed tendon at the edge of the precast concrete beam (1) Arranged in two rows; and/or the reserved holes (7) for the longitudinal prestressing tendons are arranged around the precast concrete beam (1). 9. The tunnel form prestressed pipe curtain system according to claim 1, characterized in that: said transverse prestressed tendons (4) adopt unbonded prestressed tendons.