JP4044945B2 - Interior construction method and interior structure of underground structure - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interior construction method and an interior structure of an underground structure, and more specifically, an underground structure (tunnel) constructed below a railway track or road by inserting a number of steel elements into a natural ground. ) Concerning the interior construction method of the frame.

  As one of the construction methods for constructing underground structures that are three-dimensionally crossed under railway tracks or roads, HEP & JES (High Speed Element Pull & Jointed Element Structure) is known.

  This construction method will be described with reference to FIG. 1 which is an embodiment of the present invention. For example, a large number of long steel elements 2 and 3 are formed so as to divide the cross section of the structure in a natural ground below the track 1. After parallel insertion by towing or propulsion, it is sequentially inserted into a natural ground, and concrete is placed inside the element to construct a structural frame 4 such as a box-shaped ramen type or a circular shape. It is a construction method.

  As steel elements used in such construction methods, a reference element with a square cross section and U-shaped continuous elements that are successively connected to the side of the element are used, and the joints between the elements are fully strong. Proposals have already been made on construction methods that can be bonded to each other (see Patent Documents 1 and 2).

  2 and 3 show these reference elements and connecting elements. That is, as shown in FIG. 2, the reference element 2 is formed into a quadrangular cross section by four steel plates 5, and a joint 6 having a substantially C-shaped cross section is provided at each corner along the longitudinal direction. Further, as shown in FIG. 3, the continuous element 3 is formed in a U-shaped cross section by three steel plates 7 and 8, and has the same shape as the joint 6 at each corner and the open end of the steel plate 7. The joints 9 and 10 are respectively provided along the longitudinal direction. The reference element 2 is first inserted into the ground, and then the continuous elements 3 are inserted into the ground on both sides of the reference element 2.

  At that time, as shown in FIG. 4 only on one side, the connecting element 3 is inserted into the ground while fitting the joint 10 on the open part side with the joint 6 of the reference element 2. A succeeding continuous element 3 is inserted into the natural ground in parallel with the continuous element 3 previously inserted in the natural ground, and the subsequent continuous element 3 is connected to the joint 10 on the opening side thereof. Is inserted into the natural ground while being fitted to the joint 9 on the corner side of the preceding continuous element. In this way, the continuous elements 3 are sequentially inserted into the natural ground, and the structure housing 4 as shown in FIG. 1 is constructed. The tip of each element is connected to a drilling element having substantially the same shape in which an excavator is accommodated, and each element is inserted into the ground from the starting side to the reaching side by propulsion or traction while excavating the ground. The

  Many of the structures constructed by the HEP & JES method are to be constructed with concrete after the frame is completed. In general, since the thickness of the interior work member is thin, damage such as cracking may occur. In particular, when concrete is applied as an interior work, shrinkage or drying / self-shrinkage due to temperature stress of the concrete occurs. As a result of the shrinkage, the concrete itself is constrained by the steel plate that constitutes the element (hereinafter also referred to as JES steel plate as appropriate), and thus cracks occur in the concrete. When damage such as cracks occurs in the interior work, water leakage or the like occurs in the structure, which causes a problem in function and aesthetics. In addition, even when the interior work is performed with a secondary concrete product, water leakage from the joint is unavoidable, resulting in problems in function and aesthetics.

  At present, damage or seams that occur in the interior work cannot be completely eliminated. Therefore, as a method for preventing water leakage from the interior material, a method of placing a waterproof material between the interior work is used. Waterproof materials can be broadly divided into sheet-based waterproofing that adheres sheet-like materials to JES steel plates or concrete surfaces and those that spray waterproofing materials. In this case, the waterproof material applied in the HEP & JES method is not only waterproof, but also reduces the restraint of the JES steel sheet to suppress the occurrence of shrinkage strain of the interior concrete due to temperature stress and drying / self-shrinkage, The effect of reducing the damage caused to the interior concrete is required. However, the waterproof material currently used cannot prevent damage to the interior concrete.

JP 2000-120372 A JP 2000-179282 A

The present invention has been made based on the technical background as described above, and achieves the following object.
An object of the present invention is to provide an interior construction method and an interior structure of an underground structure body that prevent leakage from interior concrete, prevent damage due to cracks, and do not impair the appearance.

The present invention employs the following means in order to achieve the above object.
That is, this invention is an interior construction method of an underground structure housing formed by inserting a number of steel elements into a natural ground,
After forming a waterproof coating layer having adhesiveness and high stretchability on the surface of the casing,
The interior of an underground structure housing, characterized in that a concrete layer is formed on the surface of this waterproof coating layer by using a cement-based fiber reinforced board formed by mixing short fibers in cement mortar and press-molding. It is in the construction method.

Further, the present invention is an interior structure of an underground structure housing formed by inserting a number of steel elements into a natural ground,
A coating waterproofing layer having adhesiveness and high elasticity formed on the surface of the casing;
A concrete layer formed on the surface of the waterproof coating layer;
It is an interior structure of an underground structure housing, which is arranged as an embedded formwork on the surface of this concrete layer, and is composed of a cement-based fiber reinforced board mixed with short fibers in cement mortar and press-molded. .

  According to this invention, the waterproof coating layer having adhesiveness and high stretchability is formed on the surface of the structure housing made of steel elements. Since this waterproof layer acts as a cushioning material between the steel plate constituting the element and the concrete, the concrete is not restrained by the steel material even if a shrinkage strain due to drying or self-shrinkage occurs in the concrete layer. Therefore, it is possible to prevent the cracks generated in the concrete layer as well as to improve the waterproof property, and to reduce the damage.

  In addition, by covering the surface of the concrete layer with a cement-based fiber reinforced board, it is possible to improve the durability performance of the structural frame made of the concrete layer and the steel material.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention, and the construction of an underground structure housing 4 using a reference element 2 and a continuous element 3 that are steel elements is the same as in the prior art. Note that the steel elements shown in FIGS. 1 to 3 are merely examples, and the present invention can be applied to a case interior work using elements having various other shapes.

  The interior structure 11 according to the present invention includes a waterproof coating layer 12 formed on the surface of the housing 4, that is, a portion in contact with the JES steel plate 7 constituting the element, as shown in FIG. The three-layer structure includes a concrete layer 13 formed on the surface and a cement-based fiber reinforced board 14 disposed on the surface so as to sandwich the concrete layer 13 therebetween.

  The waterproof material for forming the waterproof coating layer 12 is a polymer asphalt type, for example, “LIQUID BOOT” (trade name) manufactured by LBI TECHNOLOGIES, INC. Is used. This waterproof material has the characteristic of having adhesiveness as well as excellent waterproof performance. Furthermore, it has extremely excellent stretch performance (elongation rate: 1300%, restoration rate: 90%).

  When the waterproof layer 12 is constructed, the joint portions 9 and 10 of the JES steel plate protrude and there are locally discontinuous portions between the joints. Applies. The waterproof material may be sprayed on the entire surface of the housing 4, but as shown in FIG. 1, it is sufficient up to the vicinity of the lower portion of the side wall of the housing 4. That is, it is not necessary to provide a waterproof layer between the bottom concrete 15 and the frame 4. In FIG. 1, 16 and 17 indicate a sidewalk and a roadway, respectively.

  After the waterproof layer 12 is formed, concrete is cast on the surface using the cement fiber reinforced board 14 as a mold to form the concrete layer 13. The cement-based fiber reinforced board 14 is used as an embedding formwork, and is thus arranged as it is on the surface of the concrete layer 13. The fiber reinforced board 14 is formed by pressing short fibers made of synthetic fibers such as PVA fibers (polyvinyl alcohol fiber, commonly known as vinylon fibers) into cement mortar, and is press-molded. Is transmitted. Since the tensile stress is transmitted, a plurality of fine cracks are generated, resulting in excellent deformation performance. This fiber reinforced board is known by the name of REDEEM board.

According to the interior structure 11 as described above, the following effects can be obtained.
(1) Since the waterproof layer 12 has adhesiveness, adhesion between the JES steel plate 7 and the concrete layer 13 can be enhanced.
(2) Moreover, since the waterproof layer 12 has high elongation performance, it becomes a cushioning material between the concrete layer 13 and the JES steel plate 7. That is, even if shrinkage strain due to drying / self-shrinkage occurs in the interior concrete layer 13, the waterproof layer 12 acts as a buffer material and the concrete is not restrained by the JES steel plate 7. Therefore, the crack generation probability of the concrete layer 13 is reduced, and the damage can be reduced.
(3) Moreover, since this waterproof layer 12 also has the effect | action which interrupt | blocks the penetration | invasion of salt, the corrosion of the JES steel plate 7 can be prevented and durability of the structure housing 4 can be improved.

(4) By using the cement-based fiber reinforced board 14 with excellent deformation performance as an embedded formwork, even if cracks occur in the interior concrete layer 13 due to drying, self-shrinkage, etc., the cracks reach the interior work surface. Will not reach. And the crack which generate | occur | produces in this fiber reinforced board 14 is a some fine thing, and it is difficult to visually observe normally. Therefore, there is no loss of aesthetics due to cracks.
(5) Since the cement-based fiber reinforced board 14 generates only fine cracks, it is possible to suppress penetration of steel material corrosion factors such as chloride ions from the cracks. Furthermore, the fiber reinforced board is manufactured with a solid mortar, and the neutralization speed | rate is slow compared with a normal concrete member. For this reason, the improvement of the durability of the structural frame can be expected by using the cement-based fiber reinforced board as an embedded mold.
(6) By using the cement-based fiber reinforced board 14 as an embedded formwork, it is possible to prevent the interior concrete from peeling off even if the interior concrete is damaged and the adhesion to the waterproof layer 12 is broken. .

It is a whole sectional view showing an embodiment of this invention. It is the figure which showed the steel element used by the embodiment, and was seen to the axial direction. It is the figure which showed the other steel elements used in the embodiment, and was seen to the axial direction. It is a figure which shows the fitting state of elements. It is sectional drawing which expands and shows a part of structure housing | casing in which interior work was given.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Track | line 2 Reference | standard element 3 Continuously provided element 4 Structure housing 7 Steel plate 9,10 Joint 11 Interior structure 12 Coating waterproof layer 13 Concrete layer 14 Cement fiber reinforcement board

Claims (2)

It is an interior construction method for underground structures that are formed by inserting a number of steel elements into natural ground,
After forming a waterproof coating layer having adhesiveness and high stretchability on the surface of the casing,
The interior of an underground structure housing, characterized in that a concrete layer is formed on the surface of this waterproof coating layer by using a cement-based fiber reinforced board formed by mixing short fibers in cement mortar and press-molding. Construction method. An interior structure of an underground structure that is formed by inserting a number of steel elements into a natural ground,
A coating waterproofing layer having adhesiveness and high elasticity formed on the surface of the casing;
A concrete layer formed on the surface of the waterproof coating layer;
An interior structure of an underground structure housing, comprising a cement-based fiber reinforced board, which is arranged as an embedded form on the surface of the concrete layer and is formed by pressing short fibers into cement mortar .

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