KR100892137B1 - Rahmen typed underground tunnel construction method using lateral psc beam - Google Patents

Abstract

A Rahmen type underground tunnel construction method using a lateral PSC beam is provided to reduce the moment generated in the connection part of the upper slab and thus to reduce the sectional thickness of the slab and stud wall. A Rahmen type underground tunnel construction method using a lateral PSC beam comprises a step of building a pair of stud walls(120) in the direction of underground tunnel, a step of setting both ends of a lateral PSC(prestressed concrete) beam(140) on the top of the stud walls, a step of forming an underground tunnel upper slab on the top of the lateral PSC beam and stud wall, a step of connecting the lateral PSC beam bottom and the stud wall top by using a hunch unit, and a step of forming an underground tunnel base slab between the bottom sides of the stud walls and setting it on the completed underground tunnel.

Description

RAHMEN TYPED UNDERGROUND TUNNEL CONSTRUCTION METHOD USING LATERAL PSC BEAM}

The present invention relates to a ramen type underground roadway construction method using a transverse PSC beam that can be reinforced. More specifically, after excavating the ground box structure for underground roadway, after constructing the box structure in the transverse PSC beam and the ramen type, the ramen type underground using the transverse direction PSC beam that can be reinforced by the attachment method for constructing the underground road through the cover The vehicle also relates to a construction method.

Referring to FIG. 1, a method of constructing a conventional box girder underground roadway as an attachment type is as follows.

First, the ground is excavated in the direction of installation of the underground road at the location where the underground road should be constructed.

At this time, it is possible to ensure the safety of the excavated ground by installing a temporary facility such as sheet piles on the ground.

Next, the basement floor boards 10 for constructing the underground roadway box girder on the excavation bottom will be constructed.

This is because it is necessary to construct the basement driveway base plate 10 first so that a copper bar supporting the formwork can be installed first in order to install the underground driveway upper slab 30 between the column walls later.

Next, the column walls 20 are spaced apart from each other in the vertical direction (up and down direction) on the upper surface of the basement base plate 10 underground road.

Next, the first notch is installed on the pillar wall 20 so that the underground slab upper slab 30 can be constructed. The copper bar is supported on the lower portion of the base plate 10 by the underground car. The upper portion of the upper road slab (30) is not shown to form the formwork for installation.

The concrete is placed on the formwork for the underground slab upper slab 30 so that the final underground slab upper slab 30 can be constructed.

Next, by covering the completed underground roadway, the construction of the detachable underground roadway can be completed.

However, it can be seen that the underground road construction method is to install the basement base plate 10 first, as shown above, this is the basement base plate at the time of installation of the basement for the underground slab upper slab construction In the case of installing the copper bar on the bottom of the excavation without being supported by the (10), the construction of the base plate 10 for securing the bearing capacity can be performed first, since problems may arise in the construction of the underground slab upper slab 30 due to settlement of the copper bar. do.

However, when this type of work is adopted, a positive pressure (buoyancy) is generated at the bottom of the excavation of the foundation base plate 10, which is pre-installed, due to an increase in the groundwater level generated during construction.

The distribution range of the positive pressure acts upward over the entire base plate 10, wherein the corresponding load resisting the positive pressure becomes the own weight of the base plate 10 acting downward.

Therefore, when the depth of the underground excavation deepens, the positive pressure also increases, so that the cross-sectional thickness of the base bottom plate 10 correspondingly has to be increased.

If the design of the positive pressure is not properly considered, cracks may occur before or after the foundation base plate 10 is cured due to the influence of groundwater flowing into the excavation bottom, or the foundation base plate 10 may be injured. It was the cause of leakage and deterioration of durability.

Accordingly, in order to prevent the occurrence of cracks or floating on the basement base plate 10 due to the positive pressure, the virtuous cycle of increasing the thickness of the basement base plate 10 is further increased, thereby improving construction and economical aspects. It was always disadvantageous to construct in.

In addition, the underground slab upper slab (30) uses the copper bar by the cast-in-place concrete and the formwork supported by the copper bar, so that the construction performance and safety of the copper bar is a problem caused by this, making sure to prevent safety accidents in construction. If not, the risk of major accidents always remained.

In addition, when the upper slab 30 is removed after the curing of the concrete, the large moment occurs in the column wall 20 and the column wall 20 and the upper slab connection portion because all the load is applied. This moment greatly increases the cross-sectional thickness of the column wall 20 and the upper floor plate 30, which makes economic design difficult and causes deterioration in workability.

In addition, the increase in the cross-sectional thickness of the pillar wall 20 and the upper slab 30 causes the initial cracking of the concrete due to the high heat of hydration generated during curing of the concrete.

In addition, according to Korean Patent Laid-Open Publication No. 2001-83635, the underground roadway segments are installed continuously in the longitudinal direction (longitudinal direction), and a method of compressing each other using a tension member penetrating the segments in the longitudinal direction is also introduced.

Also, there was a problem that water leakage problem always exist at the connection part of the upper floor plate, and in the sections with different transverse widths, the size of these underground driveway segments must be made differently, and if there is a longitudinal gradient, it can be accommodated. There was a problem in that the underground car segment was very difficult to make.

Therefore, the present invention is to solve the problem of the initial crack and leakage of the concrete generated on the base plate 10 by the action of the positive pressure (buoyancy) caused by the increase in the groundwater level in the construction step of the basement base plate 10 underground In addition, it is not necessary to make the thickness of the underground car underfloor unnecessarily thick, so it is possible to construct economical underground car, and the underground car can be installed without slab, so the underground car can be installed with high safety and safety. In addition to this, by providing a reinforcing lateral PSC beam to reduce the size of the moment generated at the connecting portion of the column wall and the upper slab to reduce the cross-sectional thickness of the column wall and slab to enable economical underground vehicle design, In the future, additional prestress is applied to the transverse PSC beam to reduce the load capacity or defect of the structure. Reinforcement and maintenance are possible, and even when the underground road is wide, the underground car can be easily slabed, and the ramen-type underground car can be constructed using the lateral PSC beam which enables longitudinal gradient and reasonable construction depending on the site conditions. To provide a way.

The present invention to achieve the above technical problem

First, it is possible to construct the pillar wall 120 on the ground excavation bottom without first constructing the basement base plate 110 in the underground road, and then the lateral PSC beam 140 of the pillar wall 120 It is mounted on the upper surface (both simple supporting state), and forms the upper slab 130, connects (integrates) the transverse PSC beam and the column wall by the haunting portion, and the underground vehicle base foundation plate formed under the column wall ( 110) was to have a construction order to allow construction.

As a result, before the construction of the base deck of the underground road, the area of the foundation bottom was very small and the weight of the pillar wall was large, so that the positive pressure (buoyancy) was generated smaller than the downward weight of the foundation, and placed between the pillar wall and the lower part of the pillar wall. Base floor plate 110 is also relatively small compared to the existing construction method for generating a positive positive pressure generated from the base bottom. That is, since the basement base plate 110 is first constructed, the heat of hydration caused by increasing the cross-sectional thickness of the base plate in order to resist the positive pressure (buoyancy), and the problem of the increase in the cross-sectional thickness and the deterioration of workability are fundamental. It was to be solved.

Second, by installing a transverse PSC beam 140 that can be reinforced on the upper surface of the pillar wall and a formwork for underground driveway slab between the transverse PSC beams for installation of the upper slab 130 thereon without installing a separate club. Slab concrete pouring was made possible.

At this time, the self-weight of the formwork, the weight of the concrete for the underground driveway slab is transmitted to the column wall 120 by the transverse PSC beam, and the self-weight thus transferred can be transmitted to the bottom of the excavation through the column wall again more effectively It is to be able to resist against positive pressure of.

Third, the lateral PSC beam 140 is free to manufacture the length according to the width of the underground road (transverse width), if the width is long, the horizontal PSC beam is installed on the underground wall pillar wall 120 By narrowing the intervals of the car, various applications were possible depending on the width of the underground road. In addition, considering the function and efficiency, the pretension and posttension methods can be selected appropriately.

Fourth, the lateral PSC beam 140 can be installed in a ramen type with the column wall 120 so that the base plate 110 concrete is not installed in the foundation floor plate 110 concrete in the construction step And the upper slab 130 has the advantage of proceeding at the same time pouring the concrete, greatly shortened the construction period.

Fifth, the transverse PSC beam 140 allows the tension member to be tensioned and settled in the longitudinal direction of the beam, so that the upper slab 130 is prepared by simply using an RC structure using a PSC beam into which compression prestress is introduced. ) To solve crack and leakage problems.

Sixthly, according to the present invention, the underground roadway superstructure is provided with a sheath tube capable of further introducing compressive prestress to the lateral PSC beam 140, so that additional tension is introduced by the tension member when the structure is later defective or reinforced. It was made possible.

According to the present invention, it is possible to fundamentally solve the problem of leakage caused by cracking in the underground roadway, and to solve the problem of unnecessarily constructing the baseplate of the underground roadway due to the positive pressure, and the composite upper part using the lateral PSC beam The application of the bottom plate can greatly reduce the moment generated at the connection between the column wall and the upper slab, thereby greatly reducing the cross-sectional thickness of the column wall and the upper slab, and providing a sheath tube for introducing additional tension into the transverse PSC beam. It is possible to easily reinforce load loss or defect of the structure that occurs later, and it is possible to solve the safety accident problem because there is no need for construction of dongbari for the construction of the underground road slab, and the foundation by the underground roadway constructed with the ramen structure When the bottom plate and the upper slab concrete can be poured almost simultaneously Economic and rational underground road construction by shortening is possible.

An embodiment of the present invention described above and illustrated in the drawings should not be construed as limiting the technical spirit of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications fall within the protection scope of the present invention as long as it will be apparent to those skilled in the art.

BRIEF DESCRIPTION OF DRAWINGS To describe the present invention more clearly and easily, the following describes the best embodiments of the present invention in detail with reference to the accompanying drawings, and embodiments according to the present invention may be modified in various other forms, and thus the scope of the present invention. Is not limited to the embodiment described below.

Figure 2 schematically shows the construction sequence of the underground road according to the present invention.

First, as shown in Figure 2a to excavate the ground where the underground road to be located so that the ground excavation is made first (attached).

Accordingly, an underground roadway is installed on the excavated ground bottom 200.

Since the underground roadway of the present invention is to be installed in a detachable construction, the first type of trench for the underground roadway is preceded.

In the case of the excavation work, it is preferable to construct a temporary facility such as a sheet pile first in an urban area or an area in which the construction environment of the soft ground is unfavorable, and to excavate between them to enable the excavation work that enables dry work.

Next, unlike the prior art, the underground vehicle is also constructed without the first base plate, and the pillar wall 120 is constructed in the longitudinal direction (vehicle traveling direction).

When the width of the underground road is not large, one column wall 120 may be installed at each side, and when the width of the underground road is large, the inner wall may be further installed as shown in FIG. 2B.

The pillar wall may be constructed as a wall having a predetermined thickness, and the lower portion thereof may be constructed as a structure having a lower width so as to support the bottom plate.

In the upper surface of the reinforced concrete so as to project the reinforcement in the future when the concrete slab for the underground slab, the upper slab to be embedded in the reinforcement embedded in the interior of the upper slab 130 to be rigid after concrete curing.

The pillar wall 120 has a function of receiving the weight of the superstructure of the underground road, which will be described later, and delivers it to the bottom of the excavation, and may be constructed by site casting. This is because when the gradient is formed in the longitudinal direction (vehicle progress direction), the construction of the pillar wall 120 by the site casting is very efficient.

On the upper surface of the pillar wall 120, the PSC beam 140 is installed in the transverse direction as shown in FIGS. 2C and 3.

Such a beam is referred to as a lateral PSC beam 140 because it is installed in a transverse direction in the underground roadway, and is basically made of a PSC beam in which prestress is introduced.

This is because the construction of the underground roadway slab of the present invention is not a RC structure (reinforced concrete structure) but a composite structure of a PSC beam and a RC slab (prestressed structure), which does not allow cracking by compression prestress introduced into the beam. It can be seen that, such a transverse PSC beam 140 is to buy the sheath pipe for maintenance in advance to enable the re-tensioning work for the application and future maintenance according to the width of the underground roadway.

That is, the lateral PSC beam 140 is a PSC beam having a reinforcing prestress is introduced, the cross-sectional shape can be a variety of forms, in the present invention, the sheath tube in the longitudinal direction in the beam in advance in order to enable the introduction of additional tension force The description will be based on the use of a post-tensioned post-tensioned PSC beam installed in the box shape, and it can be manufactured by the pretension method.

That is, as shown in Figures 4a and 4b to reduce the self-weight of the horizontal cross-sectional PSC beam of the cross-sectional shape is manufactured in a conventional manner, and to be formed in the hollow portion inside the styropole 141 for maintaining the hollow portion Internal formwork) can be used to be embedded.

Such a transverse PSC beam may be manufactured to have a length of 20 M or less, for example, and then mounted on the upper surface of the column wall 120 in the lateral direction. In this case, the column wall will be simply supported at both ends without the inner column wall.

Accordingly, the lateral PSC beam may be mounted on the upper surface of the column wall in a short span method.

Furthermore, in the case where the underground road is large in width, as shown in FIG. 2C, horizontal PSC beams 140 are mounted between the inner column walls and both column walls 120 to continuously install the multi-span transverse PSC beams. do.

The lateral PSC beam is divided into a primary tension member 142a and a secondary tension member 142b.

The primary tension member 142a basically allows a tension member such as a PS strand to be settled after tension at a transverse PSC beam end through a non-shown sheath tube installed along the length of the beam so that compression prestress is introduced therein. ,

Secondary tension member 142b is compressed prestress through tension after inserting the strand into the sheath tube as needed after completion of upper slab 130 through the sheath tube installed along the longitudinal direction of the beam during beam fabrication. The fixing position is fixed at the inflection point position of the moment shown in Fig. 5A.

Accordingly, the primary tension member 142a is used for introducing pre-stresses in the transverse PSC beam cross section in advance in order to cope with stress generated by the self-weight of the transverse PSC beam 140 and the subsequent acting underground load.

The secondary tension member 142b is added when a crack occurs in the beam or a defect in the structure occurs due to a loss in the amount of compression prestress introduced into the transverse PSC beam after completion of the underground slab upper slab 130 or during use. The compression prestress can be introduced into the furnace lateral PSC beam.

Therefore, the secondary tension member inserts the tension member into the sheath tube when tension is required, and the tension member is not provided at the stage of manufacturing the initial transverse PSC beam.

Thus, the secondary tension member 142b should be provided with a sheath tube to be later restrained to the transverse PSC beam.

In the first method, the primary tension member is embedded in the transverse PSC beam as shown in FIG. 4A, but is disposed in a parabolic form in the transverse PSC beam, and both ends thereof are set on the neutral axis of the transverse PSC beam.

The sheath pipe for the secondary tension member 142b is disposed in a straight line below the neutral axis of the transverse PSC beam so that both ends thereof are drawn out to the outer surface of the transverse PSC beam end so that the tension member can be installed at the lead-out portion. .

The fixing position of the secondary tension member 142b should be fixed at the inflection point position that changes from the constant moment to the parent moment as shown in FIG. 5A.

The reason for this is that when the tension member is fixed at the inflection point of FIG. 5A, a moment due to the secondary tension member 142b is generated as shown in FIG. 5B, and this moment corresponds to the moment of FIG. 5A generated by the weight and the load. This is because it provides a dynamic mechanism to reduce the acting moment acting on the parent moment section of the column wall 120 and the upper slab 130 and the central moment section of the transverse PSC beam 140.

Accordingly, the moment generated in the underground driveway by the present invention is shown in Figure 5c.

In the second method, the primary tension member is set as it is, and the sheath pipe for the secondary tension member 142b is fixed at the moment inflection point position of FIG. 5A, forming a blocked-out space S3 below the transverse PSC beam, By inserting the tension material through the sheath tube pre-installed to insert the secondary tension material (142b) in the space is to be settled after the tension.

This is a technology to install the sheath tube in advance in the transverse PSC beam 140 in advance and re-tension as necessary to easily improve the structural performance of the entire underground driveway structure.

The lateral PSC beam 140 is installed in the transverse direction on the upper surface of the pillar wall 120 as shown in FIGS. 2D and 3 and spaced apart from each other in the longitudinal direction (vehicle traveling direction).

The underground slab upper slab 130 is formed in the space S2 spaced apart from the spaced side of the horizontal PSC beam 140.

Conventional underground driveway slab 130 is installed by installing the formwork for the underground driveway slab on the upper part of the copper bar installed to be supported on the base floor plate, and installed the concrete for forming the upper slab 130 on the formwork, in this method According to this study, the construction of Dongbari is inevitable, and the construction is not only very deteriorated. Also, the underground car supported by Dongbari is also a factor that increases the thickness of the base deck, column walls, upper slab, and underground car.

Accordingly, in the present invention, formwork is installed between the upper ends of the beams by using the lateral PSC beam 140 that can be reinforced to construct the upper slab 130 for the underground roadway.

That is, in order to install the slab on top of the horizontally installed PSC beam 140, the slab formwork is installed in the space (S2) between the longitudinally spaced beams, the formwork is installed so as to be placed on the transverse PSC beam Done.

The formwork is supported by the transverse PSC beams, which are spaced apart at both ends thereof, and thus does not need to be installed.

Of course, such a formwork may be used in the form of an appropriate deck plate in consideration of the longitudinal separation distance of the transverse PSC beam, other formwork for forming the upper slab may be used.

When the formwork is installed as above, the slab reinforcement is reinforced, and the upper slab ends are reinforced with the reinforcing bar and the slab reinforcing bar from the pillar wall, and the concrete for the underground roadway slab is poured to complete the underground slab upper slab 130 To make it possible. The cast-in-place concrete of the upper slab 130 has the advantage of being able to easily adjust the slope of the underground driveway with a curved underground roadway and a longitudinal gradient and a crossway gradient.
As a result, the transverse PSC beam, the column wall and the upper slab are partially integrated with each other, partially rigid and constructed in a ramen type, and the bottom and the top surface of the transverse PSC beam installed so that both ends are simply supported are in a simple supporting state (hinged state). It can be seen that the) remains.

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Next, the end of the lateral PSC beam 140 and the column wall 120 to connect the haunch 121 to each other.

This connection means that the underground roadway structure will be constructed as the final ramen structure, which in turn means the final integration of the transverse PSC beam and the column wall. In other words, the upper slab 130 is primarily constructed to be integrated with the column wall 120 and the transverse PSC beam, and the column wall and the transverse PSC beam are connected to each other through the haunch 121 to finalize the ramen structure. Let's go.

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Next, the present invention relates to the construction of the underground roadway to the PSC structure which does not allow cracking of the RC structure by the compression prestress through the sheath pipe which is pre-arranged in the longitudinal direction to the transverse PSC beam of the superstructure of the underground roadway. Compression prestress can be introduced.

In addition, since the secondary tension member 142b may be tensioned and settled any time immediately after the completion of the underground car or after a lapse of time, the introduction timing and the amount of tension may be adjusted appropriately.

As described above, when the pillar wall, the lateral PSC beam, the underground slab upper slab, and the basement slab are underground, the earth and sand 300 excavated as shown in FIG.

Accordingly, in the present invention, after the completion of the underground roadway by covering, the reinforcement and maintenance of the underground roadway can be facilitated by additional tension and settlement of the secondary tension member 142b of the lateral PSC beam.

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1 is a cross-sectional view of a conventional underground roadway.

2A, 2B, 2C, 2D, and 2E schematically illustrate the underground roadway work according to the present invention in order.

3 is a view showing a state in which a transverse PSC beam is installed on a column wall in the underground vehicle according to the present invention.

4A and 4B show examples of the transverse PSC beam of the present invention.

5A illustrates a moment diagram generated in an underground roadway.

5B illustrates a moment diagram generated when secondary tension is applied to the lateral PSC beam of the present invention.

FIG. 5C shows a moment diagram that combines FIGS. 5A and 5B.

<Description of the symbols for the main parts of the drawings>

110: underground road foundation base plate 120: pillar wall

130: underground slab upper slab 140: transverse PSC beam

142a, 142b: primary and secondary tension

200: Excavation bottom 300: Earth and sand (cover)

Claims (12)

In the box-type underground road construction method comprising the underground road base plate, Constructing a pair of columnar walls 120 by using a site-casting concrete in the underground roadway vehicle traveling direction without constructing an underground road foundation base plate in the excavation ground 200; Installing a plurality of end portions of the lateral PSC beams 140 in a simple support form on the pillar wall upper surface, spaced apart from each other in the vehicle traveling direction; Installing a formwork at a position including the transverse PSC beam upper surface to form an underground driveway upper slab 130 on the transverse PSC beam upper surface and the column wall upper surface; Connecting the lower side of the lateral PSC beam and the upper side of the pillar wall by using a haunch 121; And And forming a basement road base plate 110 between the lower inner side of the pillar wall to cover the completed underground roadway. By forming the basement base plate after the pillar wall, the transverse PSC beam, the underground slab upper slab construction, the effect of the positive pressure generated on the excavation ground during the construction of the underground road is reduced. A method for constructing a ramen underground roadway using a directional PSC beam. delete delete According to claim 1, wherein the column wall 120 is installed on each side one by one so that the transverse direction PSC beam is installed in a short span, or the inner column wall is installed between the two side pillar wall installed one by one in the transverse direction Ramen-type underground road construction method using lateral PSC beam that can be reinforced to install PSC beam in multi span. delete The method of claim 1, The reinforceable transverse PSC beam 140 is to be installed in the transverse direction on the top surface of the pillar wall that is made of prestressed concrete beam is installed tension material, The tension member of the prestressed concrete beam is divided into a primary tension member 142a and a secondary tension member 142b so that the tension member of the prestressed concrete beam is installed in a sheath tube pre-installed inside the prestressed concrete beam, but the secondary tension member 142b is completed after the underground road is completed. A method of constructing a ramen-type underground vehicle using a reinforcement transverse PSC beam that can be tensioned and settled in a space cut out at a lower portion near the end of the transverse PSC beam to enable reinforcement. delete delete delete delete delete delete

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