JPH0649828A - Structure and construction method of pressure-proof concrete wall - Google Patents

Abstract

PURPOSE:To cope with various types of ground and a change thereof sufficiently by providing a fiber reinforced sheet, a grout layer, a water-proof sheet and a concrete wall in order inside of the drilled surface of the ground. CONSTITUTION:A shotcrete layer 3 is provided on the drilled surface 2 of the ground 1. Next, the whole of a fiber reinforced sheet 6 is impregnated with the resin adhesive agent 5 by shearing it, and the sheet 6 is attached to the inner surface of the concrete layer 3. Next, a water-proof sheet 7 is attached onto the sheet 6. A lining concrete layer 7 is placed and hardened inside of the waterproof sheet 9. Furthermore, the grout material 3 is filled between both the sheets 6, 9 to form a grout layer 8 for pressing the concrete 7.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention has a great effect on, for example, a hydraulic tunnel, a headrace tunnel used for a bypass of a dam, an industrial canal, etc., a natural gas or other compressed gas, or a structure for underground storage such as liquid. The present invention relates to a concrete wall structure to which internal pressure is applied and a construction method thereof.

[0002]

2. Description of the Related Art Generally, as a construction method of a concrete wall in the above structure, for example, there is a construction method of a headrace tunnel. In this case, the cross-sectional shape and size, the magnitude of the working water pressure, the depth of soil cover, the height of groundwater level, the mechanical and hydraulic characteristics of the rock around the tunnel, the topographical conditions, and the social environment. Depending on the conditions etc., construction is done by selecting unreinforced concrete lining, reinforced concrete lining, lining steel pipe / reinforced concrete lining, etc. Also, depending on the conditions, very simple things such as unrolled tunnels, sprayed concrete linings, or
There is also a combination of a contact grout and a consolidation grout that is expected to prestress due to high pressure. Furthermore, in a higher pressure portion, a construction method is also adopted in which an inner steel pipe having a relatively large member thickness is laid, reinforcement is performed, and concrete is filled.

[0003]

However, the above-mentioned method for constructing a concrete wall has the following problems. Unreinforced concrete lining (1) Due to the limited mechanical stability and hydraulic conditions, it can only be used under limited conditions. (2) It cannot be used in fault crush zones, shallow overburdens, and highly permeable ground. If it is adopted in such a place, the lining thickness will be large, and in some cases, it will be necessary to carry out an injection work or the like for strengthening the ground and obtaining a water blocking effect, resulting in high cost. This method has a drawback that it becomes more uneconomical because it cannot flexibly respond to changes in geology or conditions. (3) The passive force of the ground against the remaining internal water pressure after the strength reduction due to the stress release due to excavation, which the ground around the tunnel has, is not sufficiently effective due to the discontinuity due to its destruction, The lining seems to be excessive. (4) It is not possible to respond adequately depending on the changing geology, and if the concrete lining cracks, there will be no water stoppage, and depending on the geology, topography or overburden conditions, a spring problem will develop. May occur.

Reinforced concrete lining (1) It is difficult to process and assemble the rebar in a narrow mine,
It will take a considerable amount of time and cost, and it will be difficult to secure personnel for this. (2) Although it is possible to deal with changes in geology to a certain extent, it is not sufficient, and it is only possible to deal with it by increasing the number of reinforcing bars (bar arrangement amount). (3) The thickness of the lining becomes necessary from the assembling of the reinforcing bars and the placing of concrete under the conditions to the construction. Also in concrete pouring, due to the severe construction conditions, it becomes soft concrete, or it is difficult to compact and becomes porous or has a large crown cavity and a low quality concrete structure, and its economic efficiency is not always required. not high. (4) Even with reinforced concrete lining, cracks may occur due to an increase in load due to geological changes, a decrease in passive force against internal water pressure, temperature changes, and differences in physical properties of concrete. In that case, sufficient water shutoff cannot be obtained, which may lead to spring water problems. (5) Under severe conditions, due to the consolidation grout with high pressure that is built to withstand a large internal water pressure, the load due to the grout pressure increases and the thickness of the lining concrete layer is limited to the internal water pressure. It will be larger than the case, and there is a risk that the design and construction will be less economical. (6) Cracks may occur in the lining concrete layer. In geological sudden changes such as the part where hard rocks and fault crush zones meet, even if the structure is reinforced concrete, there is a limit to the followability, and there is a possibility that a large difference will occur in displacement behavior and cracks will increase. .

Inner lined steel pipe / reinforced concrete lining (1) From the construction of the inner lined steel pipe, a long construction period is required due to the conflict in the construction process. (2) Construction costs are high due to the construction of lining steel pipes and the placement of reinforced concrete, which is not necessarily a rational and economical design and construction method. (3) It is extremely difficult to respond to changes in the ground, such as arranging materials for steel pipes, purchasing, cutting and processing members, using steel pipes, so there is only a way to increase the amount of reinforcing steel in reinforced concrete. There is. (4) In order to carry in and install the steel pipes, there is a need for a facility for carrying in, such as an inclined shaft and a side shaft, and equipment, and the cost is large and uneconomical. (5) The thickness of the lining concrete layer is larger than the thickness of the lining concrete layer required for design, because it is necessary to secure a space for carrying in the steel pipes, welding work of the joint portion accompanying installation, etc. It is a waste of money and is uneconomical.

[0006] In short, the conventional method of constructing a headrace tunnel has the following problems. (1) Since only the contact grout and the consolidation grout are installed on the back surface of the lining concrete, the working internal water pressure is limited to the allowable displacement limit of the lining concrete. In addition, a design in which the mechanical characteristics of the ground around which the tunnel has been excavated (functions to restrain deformation due to stress caused by internal water pressure: passive resistance force, elastic coefficient, deformation coefficient, etc.) are sufficiently exhibited. -It is not a construction method. (2) When the consolidation grout is used together with the above method, the high pouring pressure causes unbalanced bending and tensile stresses to the lining concrete from the outside, so that the pouring pressure is static. Compared to the case where water pressure acts uniformly, the lining concrete has an oversized design, which causes problems such as high construction cost and long construction period.

The present invention has been made in view of the above-mentioned problems, and it is a pressure resistant concrete wall structure capable of sufficiently responding to the type and change of geology at a location where the geology changes suddenly and sufficiently exhibiting the mechanical properties of the ground. And its construction method. Further, the present invention is
A pressure-resistant concrete wall structure that can be constructed at low cost and in a short period of time by making full use of the characteristics of concrete with high compressive strength, and by making full use of its allowable displacement limit area to withstand internal water pressure. The purpose is to provide the construction method.

[0008]

A pressure-resistant concrete wall structure according to claim 1, wherein a reinforcing fiber sheet is provided inside a tunnel excavation surface, and the reinforcing fiber sheet is provided inside the reinforcing fiber sheet. A waterproof sheet provided with a gap between the waterproof sheet, a concrete wall placed inside the waterproof sheet, and the reinforcing fiber sheet and the waterproof sheet, which are injected and solidified. And a grout layer for pressing the concrete wall through the waterproof sheet.

According to a second aspect of the present invention, there is provided a pressure resistant concrete wall construction method, which comprises a step of excavating the ground, a step of disposing a reinforcing fiber sheet inside an excavation surface formed by this step, and a step of forming the reinforcing fiber sheet. Inside, a step of disposing a waterproof sheet with a gap between the reinforcing fiber sheet, a step of placing a concrete wall inside the waterproof sheet, the reinforcing fiber sheet and the waterproof sheet And a step of injecting grout material therebetween.

[0010]

In the pressure-resistant concrete wall structure according to claim 1, the reinforcing fiber sheet having a high tensile strength disposed inside the excavation surface is waterproof with a gap between the reinforcing fiber sheet and the reinforcing transition sheet. Prestress is applied to the lining concrete that is inserted between the sheet and the inside of the sheet, and the displacement of the concrete wall due to the tensile stress generated on the outer periphery of the concrete wall due to the internal pressure of the action is restrained. Further, the grout layer injected and solidified between the reinforcing fiber sheet and the waterproof sheet presses the concrete wall.

In the method for constructing a pressure resistant concrete wall according to a second aspect of the present invention, the ground is excavated, a reinforcing fiber sheet is disposed on an excavated surface formed by the excavation, and the reinforcing fiber is provided inside the reinforcing fiber sheet. A waterproof sheet is provided with a gap between the sheet, a concrete wall is placed inside the waterproof sheet, and a grout material is injected between the reinforcing fiber sheet and the waterproof sheet to provide pressure resistant concrete. Wall construction is done.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The pressure resistant concrete wall structure and the construction method thereof according to the present invention will be described below in detail with reference to the accompanying drawings. 1 to 3 show an embodiment in which the pressure resistant concrete wall structure of the present invention is applied to a headrace tunnel. In the figure, reference numeral 1 is the ground on which an excavation pit is formed. A sprayed concrete layer 3 is formed on the excavation surface 2 of this excavation pit, and a filled concrete layer 4 is provided at the bottom of the excavation pit to form a tunnel having a circular cross section. A reinforcing fiber sheet 6 is attached via a resin adhesive 5 to the inner surface of the tunnel having the circular cross section, that is, the inner surfaces of the sprayed concrete layer 3 and the filled concrete layer 4. Inside the reinforcing fiber sheet 6, a grout layer 8 that presses the lining concrete 7 (concrete wall) is formed. A waterproof sheet 9 is attached to the inside of the grout layer 8, and the lining concrete layer 7 is formed on the inside of the waterproof sheet 9.

The reinforcing fiber sheet 6 is formed by arranging reinforcing fibers 11 in one direction on the surface of a base cloth 10 made of glass fiber, and spraying the concrete layer 3 with a resin adhesive 12.
Also, it is fixed to the filled concrete layer 4 and integrated, and the thickness of one layer is about 0.2 to 1.0 mm. The reinforcing fiber sheet 6 is attached to the sprayed concrete layer 3 or the filled concrete layer 4 with a resin adhesive 5 in a state where the longitudinal direction of the reinforcing fiber 11 is aligned with the circumferential direction of the tunnel having the circular cross section. There is. These reinforcing fiber sheets 6 are covered with a necessary lap length in the circumferential direction of the tunnel, and the necessary number of layers are stacked and laminated in sequence, whereby the entire cross section of the tunnel is covered with the reinforcing fiber sheets 6 without any gaps. In addition, if a fault fracture zone or a soft layer partially appears on the excavation surface,
By securing a predetermined lap length also in the longitudinal direction (extension direction) and stacking and laminating a necessary number of sheets, it is possible to perform construction with an enhanced reinforcing effect.

As the fibers forming the base cloth 10, for example, glass fibers are used, and the weight per unit area thereof is preferably about 80 to 430 g / m ² . The reinforcing fibers 11 fixed to the surface of the base cloth 10 are high elastic carbon fibers, high strength carbon fibers, inorganic reinforcing fibers such as glass fibers, aramid fibers, polyarylate fibers, or organic reinforcing fibers such as polyethylene fibers. Various high strength fibers such as

Examples of the inorganic reinforcing fiber such as high elastic carbon fiber, high strength carbon fiber, glass fiber or the like which can be used as the reinforcing fiber sheet 6 or the organic reinforcing fiber such as aramid fiber, polyarylate fiber or polyethylene fiber are as follows. Forka sheet FTS manufactured by Tonen Co., Ltd.
-C1-17 (elastic modulus: 25,000 kg / cm width, tensile strength: 380 kg / cm width), FTS-C0-20
(Elastic modulus: 28,000 kg / cm width, tensile strength: 2
80 kg / cm width), FTS-AT-20 (elastic modulus:
9,500 kg / cm width, tensile strength: 350 kg / c
m width), FTS-VB-20 (elastic modulus: 9,500 kg)
/ Cm width, tensile strength: 330 kg / cm width), FTS
-GE-30 (elastic modulus: 10,500 kg / cm width, tensile strength: 220 kg / cm width) and the like.

As the resin pressure-sensitive adhesive 12 for fixing the reinforcing fibers 11 to the base cloth 10, those not containing a curing agent such as an epoxy resin and an unsaturated polyester resin having high compatibility with the resin adhesive 5 are used. Further, as the resin adhesive 5 for attaching the reinforcing fiber sheet 6 to the sprayed concrete layer 3 and the filled concrete layer 4, epoxy resin such as FR-E1 and FR-E2 manufactured by Tonen Co., Ltd., FR manufactured by the same company A vinyl ester resin such as -V1 or an epoxy resin such as CP300 or CF5 manufactured by Toho Natural Gas Co., Ltd. is used.

As the waterproof sheet 9, a waterproof sheet with a water-permeable cushioning material such as an EVA (ethylene vinyl acetate) sheet or an ECB (ethylene copolymer bitumen) sheet is used.

As the lining concrete layer 7, reinforced concrete may be used, or reinforced concrete such as SFRC (steel fiber mixed concrete) or reduced reinforced concrete may be used.

As the grout material 13 used in the grout layer 8, cement paste mixed so as to obtain a predetermined strength is used.

Next, the procedure for constructing the pressure resistant concrete wall of this embodiment will be described. First, the New Austrian Tunneling Method method (hereinafter referred to as the NATM method) and the tunnel boring machine method (hereinafter referred to as the TBM) are selected according to the mechanical characteristics and topography of the ground 1 for excavating the tunnel, groundwater conditions, etc. Excavate a tunnel in the ground 1 by the construction method) or other method.

For example, when the ground 1 is excavated in a horseshoe-shaped cross section by the NATM method, the excavated surface 2 is first lined with the sprayed concrete layer 3, and then the sprayed concrete layer 3 is sprayed with the high pressure water jet. Clean the surface. Next, spring water treatment such as water-stopping grout is performed, and the damaged portions and irregularities due to the deformation are repaired with mortar, etc. Further, a concrete filling layer 4 is placed below the excavation surface 2 to form a tunnel with a circular cross section. Form.

On the other hand, when the ground is excavated in a circular cross section by the TBM method, after the primary lining such as a sprayed concrete layer is applied to the excavated circular cross section excavation surface, if necessary, in the case of the above NATM method. Similar to the above, a tunnel is formed by performing cleaning, spring treatment, and repair. In addition, depending on the conditions such as hard rock, there is a case where a tunnel is formed by performing cleaning, spring treatment, repair of fallen bedrock, etc. without performing primary lining.

Next, after the inner surface of the sprayed concrete layer 3 and the filled concrete layer 4 is subjected to a base treatment, a resin adhesive 5 is applied and the above-mentioned reinforcing fiber sheet 6 is applied to the sprayed concrete layer 3 or the filled concrete layer. Four
Paste on the inner surface of. At this time, the whole of the reinforcing fiber sheet 6 is impregnated with the resin adhesive 5 by squeezing the reinforcing fiber sheet 6 along the direction of the reinforcing fibers 11, and the resin adhesive 5 is replenished and coated on the reinforcing fiber sheet 6. , Ensure a predetermined curing time and cure. In addition, not only one layer of the reinforcing fiber sheet 6 but also the section of the tunnel, the size of the internal water pressure, the ground 1
Depending on the mechanical properties of the lining, the thickness of the lining concrete layer 7, the height of the groundwater level, and the required proof stress required from its acting external force, etc. layer).

Next, the waterproof sheet 9 is attached to the inside of the reinforcing fiber sheet 6 so as to enclose a grouting hose (not shown) used in the construction of the grout layer 8 described later. The waterproof sheet 9 used here has a thickness of 0.4 to 2. In consideration of the waterproof property of the sprayed concrete 3 and the reinforcing fiber sheet 6 and the workability at the time of attachment.
It is good to use a thing of about 0 mm.

Next, the lining concrete 7 is poured and constructed. At this time, the grouting hose (not shown) is piped according to the construction thickness of the lining concrete 7.
This grouting hose has a thickness of 2-5 mm and an inner diameter of 12
It is preferably about 25 mm. The grouting hose and the grouting pipe (not shown) are arranged with their axes in the circumferential direction of the tunnel so that the grout material 13 can be injected under a constant hydrostatic pressure condition over the entire cross section of the tunnel, and the spacing between them It is advisable to install the pipe in a length direction of the tunnel of about 1.0 to 3.0 m.

After the lining concrete layer 7 has a predetermined strength, the grout layer 8 for pressing the lining concrete layer 8 is pressed.
Perform the construction of. As the grout material 13 used here, for example, cement paste mixed so as to obtain a predetermined strength is used. In the work of injecting 13 grout materials, blocking or stop grout is performed in advance for each construction block, and it is possible to grout with a block length of 6 to 24 m in a constant hydrostatic pressure state over the entire circumference of the tunnel cross section. As described above, at least two infusion pumps may be used. In addition, the injection pressure of the grout material 13 is determined by performing a test using a test chamber (not shown) at a typical position, measuring the internal air displacement for each construction block as necessary, and adjusting the pressure behavior appropriately. adjust.

The pressing force applied to the lining concrete layer 7 takes into consideration the structure of the lining concrete layer 7, the magnitude of the working water pressure, the mechanical characteristics around the tunnel excavated ground, the material characteristics of the reinforcing fiber sheet 6, and the like. Reasonably determined.

FIG. 4 is a conceptual diagram showing the stress and displacement applied to the reinforcing fiber sheet 6 and the lining concrete layer 7 due to the pressing force of the grout layer 8 and the working internal water pressure in this embodiment. In the figure, the vertical axis Y represents stress and the horizontal axis X represents displacement. The solid line shows the stress-displacement curve of the lining concrete layer 7, and the broken line shows the stress-displacement curve of the reinforcing fiber sheet 6. The origin O indicates the state in which the lining concrete layer 7 has been cast in the above-mentioned construction procedure. In this state, when the grout material 13 is injected and the grout layer 8 that applies a pressing force is formed, the stress-displacement state of the lining concrete layer 7 passes from the origin O to the point P, and the lining concrete layer 7 It is placed in a stress-displacement state to a point Q within the allowable compression displacement. On the other hand, the stress-displacement state of the reinforcing fiber sheet 6 is placed in the stress-displacement state from the origin O to the point U. That is, at this point of time, the lining concrete layer 7 is placed in a state in which a compressive stress is applied and the reinforcing fiber sheet 6 is placed in a tensile stress. Construction of the headrace tunnel is completed in this state. After that, when water is passed through the headrace tunnel, the stress-displacement state of the lining concrete layer 7 passes from the point Q to the point R and the point S, and the allowable displacement limit T of the lining concrete layer 7 is reached. Shows changes leading to. The stress-displacement state of the reinforcing fiber sheet 6 shows a change from the point U to the allowable displacement limit V of the reinforcing fiber sheet 6.

That is, since the lining concrete layer 7 can tolerate the working internal water pressure in a wide range from the point Q to the point T, the construction method takes advantage of the characteristics of the concrete. Even if the working water pressure is larger than the allowable displacement limit T, the crack extension of the lining concrete layer 7 can be restricted within the allowable displacement limit of the reinforcing fiber sheet, and a high water blocking effect can be obtained. You can also

As described above, according to the method for constructing the pressure resistant concrete wall of this embodiment, the reinforced fiber sheet 6 having a high tensile strength formed inside the excavated surface 2 of the ground 1 is lined with the internal water pressure. The displacement of the lining concrete layer 7 due to the tensile stress generated on the outer periphery of the layer 7 is restricted. Further, the grout layer 8 presses the lining concrete layer 7. Therefore, even in a location where the geology of the ground 1 suddenly changes, by adjusting the thickness of the reinforcing fiber sheet 6, it is possible to sufficiently respond to the type and change of the geology and to fully exert the mechanical characteristics of the ground 1. it can. Further, the construction of the lining concrete layer 7 can be carried out at low cost and in a short period of time by sufficiently exerting the characteristics of the lining concrete layer 7 and making it possible to withstand the internal water pressure while widely utilizing the allowable displacement limit region.

The pressure resistant concrete wall structure of the present invention and the construction method thereof are not limited to the above-mentioned application to the headrace pressure tunnel. Not only tunnel structures that are loaded with working pressure, it is also possible to apply to concrete structures that are loaded with high working pressure, such as structures for underground storage such as natural gas and other compressed gases, or liquids. is there.

According to the pressure resistant concrete wall structure and the construction method of the present invention, the following effects can be obtained. According to the pressure resistant concrete wall structure of claim 1, a reinforcing fiber sheet is provided inside the excavated surface of the ground, and a gap is provided inside the reinforcing fiber sheet and between the reinforcing fiber sheet. Is placed and solidified between the reinforced fiber sheet and the waterproof sheet, the concrete wall placed inside the waterproof sheet, and the reinforced fiber sheet and the waterproof sheet. Since it has a grout layer that presses against the concrete wall, it provides a pressure resistant concrete wall structure that can sufficiently respond to the type and change of geology even in locations where geology changes suddenly and that can fully demonstrate the mechanical properties of the ground. can do. Also,
It is possible to obtain a pressure resistant concrete wall structure in which the characteristics of the concrete wall having high compressive strength are sufficiently exhibited, and the allowable displacement limit region is widely used to withstand the internal pressure.

According to the method of constructing a pressure resistant concrete wall of claim 2, the step of excavating the ground, the step of disposing the reinforcing fiber sheet inside the excavated surface formed by this step, and the reinforcing fiber. A step of disposing a waterproof sheet inside the sheet with a gap between the reinforcing fiber sheet and a step of placing a concrete wall inside the waterproof sheet;
From the construction method having a step of injecting grout material between the reinforcing fiber sheet and the waterproof sheet,
The pressure resistant concrete having the above effects can be constructed at low cost and in a short period of time.

[Brief description of drawings]

FIG. 1 is an enlarged side sectional view of an essential part showing an embodiment of a pressure resistant concrete wall structure of the present invention.

FIG. 2 is a front sectional view showing the same embodiment.

3 is an enlarged view of a main part of FIG. 2, the left half of which is shown in FIG.
2 is a sectional view on the side of the arrow A, and the left half is a sectional view on the side of the arrow B of FIG. 2.

FIG. 4 is a conceptual diagram showing the relationship between stress and displacement of the reinforcing fiber and the lining concrete layer due to the pressing force of the grout layer and the working internal water pressure in the same example.

[Explanation of symbols]

 1 Ground 2 Excavation surface 6 Reinforcing fiber sheet 7 Concrete wall 8 Grout layer 9 Waterproof sheet 13 Grout material

Claims (2)

[Claims] 1. A reinforced fiber sheet disposed inside an excavated surface of the ground, and a waterproof sheet disposed inside the reinforced fiber sheet with a gap between the reinforced fiber sheet and the reinforced fiber sheet. A concrete wall cast inside the waterproof sheet, and a grout layer that is injected and solidified between the reinforcing fiber sheet and the waterproof sheet and presses the concrete wall through the reinforcing fiber sheet and the waterproof sheet. A pressure-resistant concrete wall structure comprising: 2. A step of excavating the ground, a step of disposing a reinforcing fiber sheet inside the excavated surface formed by this step, and a gap between the reinforcing fiber sheet and the inside of the reinforcing fiber sheet. And a step of placing a concrete wall inside the waterproof sheet, and a step of injecting grout material between the reinforcing fiber sheet and the waterproof sheet. A method for constructing a pressure resistant concrete wall characterized by: