JP6731242B2 - Lining concrete structure in mountain tunnel and composite functional sheet for it - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lining concrete structure constructed on an excavated inner wall surface in a mountain tunnel and a composite functional sheet therefor.

In the mountain tunnel, the NATM (New Austrian Tunneling Methed) method, which mainly uses rock bolts inserted into the ground and shot concrete that is constructed along the excavated wall surface, is the mainstream.

The tunnel digging method is a blasting excavation method that excavates with explosives, a TBM method that uses a full-section excavator called TBM (Tunnel Boring Machine), and a cutter section at the tip of the boom. There are various methods such as a mechanical excavation method using a free-section excavator for excavation, but in any case, when supporting the excavation wall surface, instead of the conventional construction method using steel arch members as the main supporting material, the lock described above is used. The NATM method, which uses bolts and shotcrete as supporting materials, is widely used.

After that, lining concrete is placed on the inner surface side of the sprayed concrete to complete the tunnel.

In the construction of the lining concrete, usually, after a waterproof sheet is stretched on the inner air surface side of the shotcrete, a movable centle having a formwork having an arch-shaped cross section is used. After the centle is moved and arranged for each span and the distance between the waterproof sheet and the formwork is positioned at a predetermined position, the waterproof sheet and the formwork are connected from the concrete pouring opening (top position) provided in the centle. After pouring concrete in between and waiting for hardening, the procedure of sequentially moving the center and constructing the next concrete lining body is repeated.

However, when pouring the lining concrete, concrete is injected from the concrete pouring port at the top end by a blowing method, so that bleeding water from the concrete or bleeding water from the concrete at the top end between the lining form and the ground is Excess air will accumulate. Conventionally, a large number of mesh holes were provided in the gable formwork to discharge bleeding water and excess air.However, since the locations where these bleeding water and excess air are discharged are limited to the gable formwork, most The excess water was supposed to stay inside the concrete. As a result, a sufficient arching effect of the lining was not obtained, and the load bearing capacity of the lining was impaired, which could cause cracks and water leakage.

Therefore, in Patent Documents 1 to 3 below, various methods have been proposed for forcibly discharging the bleeding water and surplus air accumulated at the top end.

The following Patent Document 1 describes a tunnel lining construction method in which concrete is placed between the excavated surface of the natural ground and the lining form to construct the lining of the tunnel. A suction tube installation step of installing a suction tube along the tunnel axial direction so as to be arranged at the top end of the space, and placing the lining formwork at a predetermined position, and at the top end of the lining formwork. Air/water drainage material installation step of inserting air/water drainage materials into a plurality of preformed air/water drainage material insertion holes so that the tips of the air/water drainage materials come into contact with the ground side, and ground and lining type A concrete driving step of pressing concrete between the frames, and driving the concrete in the concrete driving step and discharging excess air and water through the air/drainage material, and cement through the air/drainage material. The first air/water draining step of drawing out the air/water draining material and closing the air/water draining material insertion hole at the stage when the discharge of the air is confirmed, and the suction tube after the first air/water draining step. A second air/drainage step of discharging excess air or excess water by negative pressure suction from the above and closing the inside of the suction tube by filling with a filler when the discharge of the excess air or excess water is completed. The construction method of the existing tunnel lining is proposed.

The following Patent Document 2 is a tunnel lining construction method of constructing a tunnel lining by driving concrete between the excavated surface of the natural ground and the lining form, and enclosing a fiber bundle with a fiber tube. The drain material installation process that installs the drain material that is formed along the tunnel axis direction in the arch part between the ground and the lining formwork, and presses concrete into the space between the ground and the lining formwork. At the same time, a construction method of a tunnel lining has been proposed which includes a concrete driving/draining step of discharging excess water between the ground and the lining form frame to the outside by the drain material.

In Patent Document 3 below, a strip-shaped sheet having a structure that allows the infiltration of excess water and cement paste at a predetermined concrete pressure is continuously arranged outside the filling space from a site where air traps easily occur in the concrete filling space. After that, when pouring and filling concrete into the filling space sequentially, in a certain direction of the strip-shaped sheet in the filling space, the concrete having a predetermined concrete pressure or more is poured and filled, and the strip-shaped sheet is filled. By discharging the air and surplus water through the strip-shaped sheet to the outside of the filling space while infiltrating the cement paste into the concrete, the concrete-filled space is filled with concrete with almost no air pockets, and the strip-shaped sheet is cemented. A concrete filling method for forming a composite integrated with a paste has been proposed.

JP, 2005-90030, A JP, 2005-90031, A JP, 2015-113598, A

However, the method of discharging the bleeding water or the excess air according to Patent Documents 1 to 3 is not sufficient as a measure for discharging the bleeding water or the excess air due to a partial measure limited to the top end of the tunnel arch. there were.

By the way, in the tunnels constructed in the past, cracking of the lining concrete frequently occurred about 10 years after the service, which is a social problem. According to the previous report (“Estimation of the cause of cracks in large section (Utatsu) tunnel” Hokuriku Regional Development Bureau Project Research Presentation, July 2012), the cause is “due to the progress of water pressure or looseness after service. Earth pressure effect" Due to such cases, there are relatively many cases of cracking after service.

For lining concrete, as a general rule, concrete placement is to be performed after the deformation of the support work (ground) has converged, but the convergence judgment is "road tunnel observation and measurement guidelines 2009 revised version" ( According to the Japan Road Association (February, February, H2), "There is no hindrance to the construction of the lining if the displacement speed of the inner air displacement is about 1 to 3 mm/month or less for about 2 weeks." Based on this fact, there are many tunnels in which lining concrete is placed without waiting for complete convergence (see Fig. 9). Placing the lining concrete after waiting for the most complete convergence is not realistic because it causes a significant delay in construction.

Therefore, a main object of the present invention is to automatically and effectively drain bleeding water (including excess air) generated during lining concrete pouring in a lining concrete structure in a mountain tunnel, without any hand, and in service. Later lining concrete in a mountain tunnel that prevents cracks from occurring in the lining concrete by absorbing the external deformation from the ground side by absorbing the small ground deformation after the lining concrete construction. To provide a structure.

In order to solve the above problems, the present invention according to claim 1 is a lining concrete structure constructed on an excavated inner wall surface in a mountain tunnel,
The lining concrete structure is sprayed concrete sprayed with a predetermined thickness along a rock excavation surface, a waterproof sheet stretched on the inner air surface side of this sprayed concrete, and an inner space of this waterproof sheet. Consisting of a multifunctional sheet stretched on the surface side, and lining concrete placed on the inner air surface side of this multifunctional sheet,
The multi-functional sheet is composed of a resin monofilament molded into a three-dimensional reticulated structure, and has a bleeding water discharge function that discharges bleeding water generated during the placing of lining concrete to the outside, and a minute amount generated in the ground after use. It has a deformation absorption function that absorbs deformation and reduces the external load from the ground side to prevent the occurrence of cracks, and also allows bleeding water to pass through the lining concrete surface side, but the passage of concrete. There is provided a lining concrete structure in a mountain tunnel, which is integrally provided with a water-permeable filter layer constituted by a non-woven fabric for preventing the above-mentioned.

In the invention according to claim 1, the lining concrete structure is sprayed concrete sprayed with a predetermined thickness along a ground excavation surface, and waterproofing stretched on the inner air surface side of the sprayed concrete. A sheet, a multi-functional sheet stretched on the inner air surface side of the waterproof sheet, and a lining concrete placed on the inner air surface side of the multi function sheet. Then, as the multifunctional sheet, a bleeding is formed of a resin monofilament such as polyester or polypropylene molded into a three-dimensional reticulated structure (loofah structure), and bleeding water generated when the lining concrete is poured is discharged to the outside. It has a water drainage function and a ground deformation absorption function that reduces the external load from the ground side and prevents the occurrence of cracks by the deformation absorption characteristic that absorbs minute deformation that has occurred in the ground after use.

Further, the multifunctional sheet integrally includes a water-permeable filter layer that allows bleeding water to pass through on the lining concrete surface side but blocks passage of concrete. When concrete penetrates into the multifunctional sheet and hardens, it cannot exert its natural deformation absorption function, so bleeding water is passed through to the lining concrete surface side of the multifunctional sheet. A water-permeable filter layer made of a non-woven fabric is provided to prevent the passage of water.

Therefore, when pouring lining concrete, bleeding water (including surplus air) generated from the concrete is adjacent to the ground side of the lining concrete and is applied to the entire circumference (excluding the bottom slab side) of the inner surface of the tunnel. By the multi-functional sheet stretched along the above, it becomes possible to automatically and effectively discharge almost the entire amount of the same without putting a hand. In addition, even if a slight deformation occurs in the ground due to overburden load, loose load, water pressure action and unbalanced load after use, the multifunctional sheet absorbs the ground deformation, so Therefore, since the external load is reduced, it is possible to effectively prevent the lining concrete from cracking.

As the present invention according to claim 2, wherein the multifunctional sheet, lining concrete structures in mountain tunnel according to claim 1 Symbol mounting having a thickness of 20~40mm is provided.

In the invention described in claim 2 , the thickness of the multifunctional sheet is defined. In view of the absorption performance of the slight deformation of the target ground, the thickness of the multifunctional sheet is preferably 20 to 40 mm.

As the present invention according to claim 3 , a composite functionality for a lining concrete structure in a mountain tunnel according to any one of claims 1 and 2 , wherein the waterproof sheet and the multifunctional sheet are laminated and integrated. Seats are provided.

In the invention according to claim 3 , if a composite functional sheet produced by a factory in advance, in which the waterproof sheet and the multifunctional sheet are laminated and integrated, is carried into a site and constructed, It is possible to save the work of separately tensioning the waterproof sheet and the multi-functional sheet, and to stretch both by a single stretching operation.

As described above in detail, according to the present invention, in a lining concrete structure in a mountain tunnel, bleeding water (including excess air) generated at the time of placing the lining concrete is drained automatically and effectively without any hand. By absorbing the small ground deformation after construction of the lining concrete after use, it is possible to prevent external load from acting on the lining concrete and prevent cracks in the lining concrete. Become.

It is a perspective view showing the construction point of the lining concrete structure concerning the present invention. It is the cross-sectional view. It is an enlarged view showing a section composition of a lining concrete structure. It is a tunnel longitudinal cross-sectional view which shows the construction point of a tunnel. (A) shows the conventional structure, and (B) shows the present invention, showing the procedure for discharging bleeding water and excess air. It is an expanded sectional view which shows the deformation state of the lining concrete structure by the ground deformation of the conventional structure. It is an expanded sectional view showing the modification state of the lining concrete structure by the natural deformation of the present invention. It is specific example (A)-(C) which shows the structure of the multifunctional sheet 6. It is a time-dependent change figure of the air displacement in a tunnel.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. When referring to a direction, the center side of the tunnel is called the “inner surface side” and the opposite direction is called the “ground side”.

The lining concrete structure constructed on the inner wall surface of the mountain tunnel according to the present invention is, as shown in FIG. 3, sprayed concrete 4 sprayed with a predetermined thickness along the rock excavation surface, and this sprayed concrete. The waterproof sheet 5 stretched on the inner air side of the concrete 4, the multi-functional sheet 6 stretched on the inner air side of the waterproof sheet 5, and the inner air side of the multi-functional sheet 6 It consists of the lining concrete 7 that was cast,
The multi-functional sheet 6 has a bleeding water discharge function for discharging bleeding water (including excess air) generated during the pouring of lining concrete to the outside, and a deformation absorption characteristic for absorbing a slight deformation generated in the ground after use. And has a function of absorbing natural deformation that reduces the external load from the natural ground side and prevents the occurrence of cracks.

In addition, the lining concrete structure according to the present invention is mainly used for vulnerable rock sections (ground rock classification: DIII, DII, DI, IS, IN, etc.) with high crack occurrence rate due to external force after completion. It is desirable to apply.

The present invention will be described in more detail below.

First, we will outline the construction procedure for mountain tunnels.

As shown in FIG. 4, in the tunnel T, a wheel jumbo for drilling, charging, supporting construction, rock bolt driving work, a powder carrier, a wheel loader for slipping out, and a slide. Various types of tunnels such as transport dumpers, breakers for hitting, backhoes, erectors for steel support construction, sprayers for spraying work, mixer trucks, trucks for placing rock bolts, etc. Construction heavy equipment is placed. Then, depending on the type of construction, a specific tunnel construction heavy machine moves to the front of the face S to perform work. In the figure, only the wheel jumbo 1, the spraying machine 2, and a later-described center 3 are shown.

The excavation procedure for tunnel construction shown in Fig. 4 is an example of a mini bench construction method in which excavation is performed by a batch of parallel work in the upper and lower halves, and the upper half bench length is extremely shortened to 3 to 5.5 m. After drilling rock bolts and charging holes/charging in each of the upper and lower halves, cut the upper and lower halves at once (blasting), then slide out → hit → sprayed concrete → Excavation work is performed every cycle by the procedure of placing the lock bolt. Then, the center 3 is installed on the rear side thereof, and after waiting for the convergence of the inner air displacement (about 1 to 3 mm/month or less as described above), the lining concrete is continuously poured.

The center 3 is installed at the rear of the heavy construction machine for tunnels, and forms a space for the thickness of the lining concrete 7 with the inner wall surface 4a of the sprayed concrete 4 of the tunnel T, as shown in FIG. The mold frame member 30 arranged as described above, the support frame 31 that supports the mold frame member 30, and the traveling rail 32 that is capable of traveling and is laid on the bottom surface of the tunnel T. It

The formwork member 30 is provided along the inner wall surface of the tunnel T, and the outer surface thereof is formed to be smooth, and is made of a material excellent in peelability from concrete. The form member 30 is divided into a plurality of parts in the circumferential direction of the tunnel T, and the parts are connected to each other. Further, a gable form (not shown) is provided on the front and rear end surfaces of the form member 30. A concrete pouring port 10 for pouring concrete is provided in the vicinity of the mine mouth side above the formwork member 30, and the concrete is poured from here.

Prior to the lining concrete pouring using the center 3, a waterproof sheet 5 is stretched on the inner wall surface of the sprayed concrete 4, and further the multifunctional sheet 6 is stretched adjacent to the waterproof sheet 5. After these sheets 5 and 6 are installed, the center 3 is moved to a predetermined position and the lining concrete 7 is poured.

[Tunnel lining concrete structure]
The lining concrete structure constructed on the inner wall surface of the natural ground J by the tunnel construction described in detail above has a predetermined thickness along the natural rock excavation surface in order from the natural rock J side as shown in FIG. It is composed of sprayed sprayed concrete 4, a waterproof sheet 5, a multifunctional sheet 6, and a lining concrete 7. The sprayed concrete 4, the waterproof sheet 5, the multifunctional sheet 6, and the lining concrete 7 have the same cross-sectional structure over the entire inner circumference of the tunnel except the bottom slab side.

The sprayed concrete 4 is a concrete sprayed by the spraying machine 2 along the circumferential surface of the wall surface with a predetermined thickness after excavation, and is constructed in a range of 50 mm to 250 mm depending on the ground classification. The working effects of this shotcrete concrete 4 are (1) adhesive force with bedrock, (2) support effect by shear resistance, (3) internal pressure effect, (4) ring closing effect, (5) external force distribution effect, 6) Strengthening effect of weak layer, (7) Covering effect. This shotcrete needs to be shot immediately after excavation in order to exert these effects. In addition, wire mesh may be installed as a reinforcement when ground conditions are poor.

As shown in FIG. 2, lock bolts 8, 8... Are installed with the inner sky surface of the shotcrete 4 as a fixing surface toward the natural ground J. The lock bolt 8 is shown in FIG. Omitted. The effect of the lock bolt is (1) sewing effect (hanging effect), (2) beam forming effect, (3) internal pressure effect, (4) arch forming effect and the like.

As the waterproof sheet 5, a waterproof resin sheet on the lining concrete 7 side and a cushioning sheet (mainly non-woven fabric) on the spray concrete 4 side are bonded together to form a single sheet. The waterproof resin sheet has a waterproof function on the ground side and an edge cutting function with the lining concrete side, and the buffer sheet has a water guiding function on the spraying surface side and a damage preventing function such as tearing by a projection on the spraying surface. It is a thing. The waterproof resin sheet has a thickness of 0.8 mm and the buffer sheet has a thickness of 3.0 mm, which is a total of 3.8 mm.

In the present invention, the multifunctional sheet 6 is stretched adjacent to the waterproof sheet 5. This multi-functional sheet 6 has a bleeding water discharging function for discharging bleeding water (including excess air) generated during the pouring of lining concrete to the outside, and a deformation absorbing characteristic for absorbing a slight deformation generated in the natural ground after use. And has a function of absorbing natural deformation that reduces the occurrence of external load from the natural ground side and prevents the occurrence of cracks. As another performance required for the multifunctional sheet 6, it is desirable that the multifunctional sheet 6 has a pressure resistance that maintains a constant thickness even when a lining concrete is subjected to a casting pressure. Further, it is desirable that the lining concrete has a smoothness that does not impair the fluidity of the concrete when it is poured. Furthermore, it is desirable to have appropriate workability (thickness/weight) when it is attached to the waterproof sheet 5.

The multifunctional sheet 6 has a water-permeable filter layer that allows bleeding water to pass through the lining concrete surface side so that the concrete does not enter when the lining concrete is poured, but blocks the passage of concrete. ing.

Therefore, when pouring lining concrete, the bleeding water and surplus air generated from the concrete can be automatically and effectively discharged almost entirely by the multifunctional sheet 6 without any hand. Becomes That is, in the case of the conventional structure, as shown in FIG. 5(A), the suction tube, the drain material, and the strip-shaped sheet are arranged only in the top end portion to discharge the bleeding water and the excess air accumulated in the top end portion. However, in the present invention, as shown in FIG. 5(B), bleeding water and surplus air from the entire circumferential surface of the tunnel except the bottom plate on which the multifunctional sheet 6 is disposed can prevent the multifunctional sheet 6 from flowing. Since it flows in the inside, flows in the longitudinal direction of the tunnel, and is discharged from the end surface (gable form surface), almost all the amount of bleeding water and excess air can be automatically and effectively removed without any hand. It becomes possible to discharge.

Further, even if a small amount of ground deformation occurs in the ground due to overburden load, loose load, water pressure action, unbalanced load, etc. after use, the multifunctional sheet 6 absorbs the ground deformation, so that the lining concrete It is possible to effectively prevent the lining concrete 7 from being cracked due to an external load being reduced from the natural ground side. That is, in the case of the conventional structure, as shown in FIG. 6, when the ground is displaced due to overburden load, loose load, hydraulic action, unbalanced load, etc. after use, all the external load is applied to the blast concrete 4 and When the lining concrete 7 is subjected to the external load, a crack is generated on the inner surface side of the lining concrete 7. On the other hand, in the case of the present invention, as shown in FIG. 7, since the multifunctional sheet 7 is arranged adjacent to the ground side of the lining concrete 7, a slight deformation is caused in the ground. Even if it occurs, the multifunctional sheet 7 is compressed and deformed according to the deformation and absorbs the deformation, so that the external force exerted on the lining concrete 7 is considerably reduced here, so the lining concrete 7 is cracked. Can be prevented.

Specific examples that can be used as the multifunctional sheet 6 will be described below.

First, in the first example, as shown in FIG. 8(A), the bleeding water draining function and the ground deformation absorbing function are provided by stacking a plurality of nonwoven fabrics whose surface is uneven. The permeable filter on the concrete surface side of the lining, which is composed of a drainage/deformation absorption function layer 6B on the ground surface side and a film having a large number of fine pores formed to pass the bleeding water but to prevent the passage of concrete. Mention may be made of a multifunctional sheet 6 comprising a layer 6A.

The multifunctional sheet 6 according to the first example is an improvement of the trade name "FS foam" (filter sheet) [manufactured by Fujimori Sangyo Co., Ltd.]. The filter sheet is a laminated sheet of a non-woven fabric (one sheet) having an uneven surface and a film having a large number of fine pores formed thereon. The thickness is ensured to have a bleeding water discharge function and a ground deformation absorption function.

Next, in the second example, as shown in FIG. 8(B), the resin bleeding function and the ground deformation absorption function are given by a resin monofilament molded into a three-dimensional network structure (loofah structure). The drainage/deformation absorption function layer 6B on the ground surface side and the water permeable filter layer 6A on the lining concrete surface side that is made of a non-woven fabric to allow the passage of bleeding water but prevent the passage of concrete. The functional sheet 6 can be mentioned.

The multifunctional sheet 6 according to the second example is one in which the product name “Hetimalon” [manufactured by Shinko Nylon Co., Ltd.] and the product name “Endren Mat” [Maeda Kosen Co., Ltd.] are applied to the present invention. .. The three-dimensional network structure composed of this resin monofilament has a predetermined pressure resistance and can be used as the multifunctional sheet 6 of the present invention.

The third example is, as shown in FIG. 8C, drainage/deformation on the ground surface side where the bleeding water discharging function and the ground deformation absorbing function are given by a plastic sheet molded in a special shape. An example of the multifunctional sheet 6 includes an absorbent functional layer 6B and a water permeable filter layer 6A on the lining concrete surface side which is made of a non-woven fabric for allowing bleeding water to pass therethrough but preventing the passage of concrete.

The multifunctional sheet 6 according to the third example is obtained by applying the trade name "green sheet" [manufactured by Dainippon Plastics Co., Ltd.] to the present invention. The plastic sheet molded into a special shape has a predetermined pressure resistance and can be used as the multifunctional sheet 6 of the present invention.

The thickness of the multifunctional sheet 6 is 20 to 40 mm, preferably 20 to 30 mm. Further, since it is desired that the surface of the waterproof sheet is smooth when the multifunctional sheet 6 is attached, it is desirable to adopt the back smooth tunnel lining method (FILM). This lining method fills the gap between the uneven part of sprayed concrete and the waterproof sheet installed in the formwork with backfilling filler, finishing the back of the lining concrete into a smooth tunnel shape and adhering the waterproof sheet to the entire surface. It is a construction method. By adopting this construction method, since the waterproof sheet surface becomes smooth, the work of attaching the multifunctional sheet 6 becomes easy, and the multifunctional sheet 6 is stretched as a clean continuous body along the circumferential direction without any step. Will be able to.

[Another form example]
(1) In the above embodiment, after the waterproof sheet 5 is stretched on the inner wall surface of the sprayed concrete 4, the multifunctional sheet 6 is further stretched adjacent to the waterproof sheet 5, and the lining concrete 7 is covered. It was set up. That is, the work of stretching the waterproof sheet 5 and the multifunctional sheet 6 is performed separately, but in advance, in the factory, the waterproof sheet and the multifunctional sheet are laminated and integrated into a combined functionality. If you make a sheet and carry it to the site for construction, you can save the work of separately tensioning the waterproof sheet and the multifunctional sheet, and install both by a single stretching operation. It becomes possible to do.

DESCRIPTION OF SYMBOLS 1... Wheel jumbo, 2... Spraying machine, 3... Centr, 4... Spraying concrete, 5... Waterproof sheet, 6... Multifunctional sheet, 7... Lining concrete, 8... Rock bolt, 10... Concrete pouring port , J... Ground, T... Tunnel, S... Face

Claims (3)

A lining concrete structure constructed on an excavated inner wall surface in a mountain tunnel,
The lining concrete structure is sprayed concrete sprayed with a predetermined thickness along a rock excavation surface, a waterproof sheet stretched on the inner air surface side of this sprayed concrete, and an inner space of this waterproof sheet. Consisting of a multi-functional sheet stretched on the surface side, and lining concrete cast on the inner air surface side of this multi-functional sheet,
The multi-functional sheet is composed of a resin monofilament molded into a three-dimensional reticulated structure, and has a bleeding water discharging function that discharges bleeding water generated during the placing of lining concrete to the outside, and a minute amount generated in the ground after use. It has the function of absorbing the deformation of the ground by reducing the external load from the ground side and preventing the occurrence of cracks by the deformation absorption characteristic that absorbs the deformation, and allows the bleeding water to pass through to the lining concrete surface side, but the passage of concrete. A lining concrete structure in a mountain tunnel, which is integrally provided with a water-permeable filter layer composed of a non-woven fabric for preventing the above-mentioned phenomenon. The multifunctional sheet, lining concrete structures in mountain tunnel according to claim 1 Symbol mounting having a thickness of 20 to 40 mm. The composite functional sheet for a lining concrete structure in a mountain tunnel according to claim 1 , wherein the waterproof sheet and the multifunctional sheet are laminated and integrated.

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