JP5182922B2 - Water stop grout method and system under high water pressure - Google Patents

Description

  The present invention relates to a still water grout construction method and system under high water pressure, and more particularly to a still water grout construction method and system for dealing with high water pressure spring water that can be generated when a tunnel is constructed deep underground.

  The deep underground layer has shielding performance such as poor permeability and low air permeability, and the development of technology to store and dispose of unnecessary substances on the ground in the underground layer using such shielding performance. Is underway. For example, in order to isolate and dispose of radioactive waste (including radionuclides) generated from nuclear power plants from the human living environment, as shown in FIG. The construction of a geological disposal facility for confining radioactive waste in a disposal mine 6b constructed in a stable rock bed (referred to as Non-Patent Document 1) is planned.

  The geological disposal facility in FIG. 4 (A) is composed of a ground facility 3 and an underground facility on the surface 2, and the underground facility is composed of a plurality of disposal tunnels 6b constructed in the deep underground layer 1 and main tunnels 6a interconnecting them. The access shaft 4 is used for workers to enter and exit the disposal tunnel 6b from the surface 2, and the access inclined shaft 5 is used to carry radioactive waste from the surface 2 to the disposal tunnel 6b. After the radioactive waste is carried and accumulated in the disposal mine 6b of the underground facility, the inside of the disposal mine 6b is filled with a buffer material such as bentonite to be backfilled, so that the shielding performance of the deep underground layer 1 is restored. Radionuclides in radioactive waste continue to exist while decaying over a long period of time, but radionuclides are transferred to the human living environment by being confined by multiple barriers combining the deep underground layer 1 with shielding performance and buffer materials Can be expected to be reliably deterred over a long period of time.

  When constructing a geological disposal facility as shown in FIG. 4 (A), as shown in FIG. 4 (B), first, a shaft 4 or an inclined shaft 5 for accessing the deep ground 1 is excavated, and then the deep ground 1 The main tunnel 6a and the disposal tunnel 6b (hereinafter, both may be collectively referred to as the tunnel 6) are developed in the horizontal direction and excavated. When excavating the tunnel 6, it is important not to create a water channel or the like that can be an excellent transition path for radionuclides. In addition, it is assumed that there are unconsolidated layers that cause spring water, cracks that become water channels, fault fractures, and highly permeable fractures (hereinafter referred to as spring formation layers) in the deep underground layer 1 However, a considerably high differential pressure can be generated between the excavated tunnel 6 (atmospheric pressure) and the groundwater level near the ground (for example, a pressure difference of 3 MPa for a tunnel of 300 m underground and 10 MPa for a 1000 m underground). If there is a spring formation layer 8 when excavating the tunnel 6 as shown in Fig. 5 (B), a large amount of high-pressure spring 9 is suddenly generated, which has a great impact on the safety and process of construction. Therefore, when excavating the mine 6, countermeasures against the spring 9 are indispensable.

  Conventionally, as a typical countermeasure work for the spring water 9, a water draining method in which a water draining boring hole is provided in the spring water generating ground 8, and a grout material (cement-based material, clay-based material, etc.) is injected into the spring water generating ground 8. The still water grout method is known. In general excavation work such as a mountain tunnel, the drainage method is first applied because drainage is generally easy, and the water stop grout method is applied when it is still insufficient. On the other hand, when constructing a geological disposal facility, if groundwater is collected in the tunnel 6 by the drainage method, the groundwater level in the surrounding area is lowered and the geological and chemical environment of the tunnel 6 is disturbed. Since there is a possibility of impairing the shielding performance, it is considered preferable to use a water-stopping grout method that does not lower the surrounding groundwater level as much as possible (see Non-Patent Document 2). Further, the water drainage method in the deep ground layer 1 has a problem that the pumping distance to the ground becomes long, so that the cost is higher than that of a normal water drainage method such as a mountain tunnel.

  As a waterproofing grouting method for constructing a structure (such as a tunnel) in the basement, Patent Document 1 forms a plurality of holes from the structure to the surrounding permeable rock, and cement milk (grouting material) in any of the holes. ) Is injected at a pressure of 3 to 10 MPa, and the process of draining excess water from other holes is sequentially repeated for a plurality of holes, and in each step, the concentration is low (ratio of cement / water is 1/30 to 1/500) By using the cement milk and gradually increasing the injection pressure as the cement milk is injected, the water stop area filled with the cement milk up to the depth or detail of the crack (spring formation layer) in the bedrock The grout method to be formed is disclosed. In addition, Patent Document 2 discloses that when a seepage water flow (groundwater flow) exists in the rock mass to be stopped, a clay suspension (grouting material) is removed from a grout inflow hole (boring hole) formed on the upstream side of the water flow. A grout method that fills cracks (spring formations) in the bedrock with a uniform and high density by allowing the clay suspension to naturally flow down into the space (tunnels, etc.) formed downstream of the water flow. Disclosure.

JP 2006-299741 A Japanese Patent No. 2691252 Japan Federation of Electric Power Companies / Nuclear Fuel Cycle Development Organization “TRU Waste Disposal Technology Review Chapter 3; Engineering Technology for Geologic Disposal”, September 2005, Internet <URL: http: // www. fepc-atomic. jp / nuclear / waste / tru / 001. html> Yuki Sato et al. “Toward 1,000m underground: Construction plan of Mizunami Underground Research Laboratory” Cycle Organization Technique, No. 20, September 2003, Internet <URL: http: // jolisfukyu. tokai-sc. jaea. go. jp / fukyu / gihou / pdf2 / n20-04. pdf>

  However, as in Patent Document 1, the still water grouting method for injecting the grouting material into the spring water generating layer does not have an appropriate device (such as a pump) that can inject the grouting material under high water pressure as in the deep layer 1. There is a problem. In general, it is necessary to inject the grout material at a pressure two to three times the spring pressure (external water pressure) in the still water grout method, and in normal mountain tunnels, etc., if the injection pressure is about 7-8 MPa at the maximum, Although injection is possible, for example, in the deep underground layer 1 with a depth of about 1000 m, the spring pressure is also about 10 MPa, so the existing injection device cannot inject the grout material. Even if an appropriate injection device for injecting grout material in the deep ground layer 1 can be developed, it is necessary to increase the injection pressure very much. Therefore, depending on the type and condition of the surrounding rock mass, splitting fracture ( There is also a problem that cracks and the like may occur. When a fracture (crack) occurs in the bedrock of the deep underground layer 1, it can become a water channel serving as a radionuclide migration path, and the shielding performance of the deep underground layer 1 is impaired. There is a demand for the development of a still water grout method that can be constructed without destroying the bedrock in deep layers of high water pressure.

  On the other hand, when the flow of groundwater as disclosed in Patent Document 2 is present in the deep ground layer 1, it can be expected to inject the grout material using the flow. However, even if the actual underground water in the deep ground layer 1 is stopped or flowing, the flow rate is extremely low, and the method of Patent Document 2 is often not applicable to the deep ground layer 1. Moreover, in the construction method of Patent Document 2, since the grout material naturally flows down in the direction of groundwater flow, there is also a problem that the grout material penetrates into places other than the spring water formation layer. In order to maintain the geological and chemical environment of the deep layer 1, it is desirable to limit the injection range of the grout material G to the spring generation layer as much as possible and avoid infiltration into unexpected locations. Furthermore, in the construction method of Patent Document 2, there is a possibility that the flow stops when the grout material supplied from the upstream side of the water flow is filled in the crack (spring formation layer). Thus, in order to supply the grout material upstream, it is necessary to increase the injection pressure. Therefore, there is still a possibility that fracture (crack) occurs in the bedrock of the deep underground layer 1.

  Therefore, an object of the present invention is to provide a still water grouting method and system that can be constructed in a deep layer of high water pressure without destroying the rock mass.

Referring to the embodiment of FIG. 1, the high water pressure still water grouting method according to the present invention is a high water pressure spring that can be generated when a deep underground tunnel 6 (see the tunnels 6a and 6b in FIG. 4A) is constructed. In the still water grouting method for suppressing water 9 (see FIG. 4 (B)), a grouting hole 11 and a draining hole 21 are drilled from the tunnel 6 to the surrounding spring generation geology 8 (see also FIG. 4 (B)). The pressure gauge 13 and the grout injection device 15 are connected to the hole 11, the control valve 22 and the drainage device 25 are connected to the drain hole 21, and the control valve 22 of the drain hole 21 is gradually expanded to increase the pressure in the grout hole 11. meter 13 drives the injection device 15 after having adjusted the initial opening degree equal to or less than a predetermined pressure P is lower than seepage water pressure injected grout G, the grout G injection proceeds by pressure gauge 13 of the grout holes 11 Control valve according to pressure rise By expanding the 22 opening of those formed by maintaining the pressure gauge 13 below the predetermined pressure P.

Referring also to the block diagram of FIG. 1, the high water pressure still water grout system according to the present invention is a high water pressure spring 9 that can be generated when a deep underground tunnel 6 (see the tunnels 6a and 6b in FIG. 4) is constructed. (In the still water grouting system for suppressing FIG. 4 (B), a pressure gauge 13 and a grouting material injection device connected to the grouting hole 11 bored from the tunnel 6 to the surrounding spring generation geology 8 (see also FIG. 4 (B)). 15. The control valve 22 and drainage device 25 connected to the drain hole 21 drilled from the tunnel 6 in the spring generation geology 8 and the control valve 22 of the drain hole 21 are gradually expanded to increase the pressure gauge 13 of the grout hole 11. control valve according to the pressure gauge 13 pressure rise of the grout holes 11 but by infusion progression Spring drives the grout injection device 15 after having adjusted the lower predetermined pressure P hereinafter become initial opening than the water pressure and grout G And expanding the second opening in which a pressure gauge 13 comprising a control device 26 for maintaining below the predetermined pressure P.

  Preferably, a drainage flow meter 24 is provided in the drain hole 21, and the opening degree of the control valve 22 is increased in accordance with a decrease in the drainage flow rate of the drainage flowmeter 24 instead of or in addition to the pressure increase of the pressure gauge 13. More preferably, the injection of the grout material G into the grout hole 11 is continued until the control valve 22 of the drain hole 21 is fully opened and the drainage flow rate of the drainage flow meter 24 becomes a predetermined flow rate W or less. Desirably, as shown in FIG. 1, the grout material injection device 15 includes an adjusting device 16 that adjusts the viscosity or curing speed of the grout material G, and the drainage of the drainage flow meter 24 when the grout material G is injected into the grout hole 11. When the flow rate is not reduced, the viscosity or curing rate of the grout material G is increased.

The water pressure grouting method and system according to the present invention connects a pressure gauge 13 and a grouting material injection device 15 to a grouting hole 11 drilled in a surrounding spring water generating geology 8 from a deep underground tunnel 6 and the spring water generated geologic 8 connects the control valve 22 and the drainage device 25 to drain hole 21 bored from the tunnel 6, a pressure gauge 13 of the grout holes 11 spread gradually control valve 22 of the drainage holes 21 Spring pressure The grout material injection device 15 is driven after adjusting the initial opening to be lower than the lower predetermined pressure P, the injection of the grout material G is started, and the pressure of the pressure gauge 13 in the grout hole 11 by the progress of the injection of the grout material G since continued injection of grout G while maintaining the pressure gauge 13 below the predetermined pressure P by expanding the opening of the control valve 22 in response to an increase offers the following remarkable effects.

(A) Since an artificial hydrodynamic gradient U is formed between the grout hole 11 and the drain hole 21 by adjusting the opening degree of the control valve 22 of the drain hole 21, even if the bedrock strength in the deep underground is weak The grout material G can be injected by adjusting the opening of the control valve 22 so that the grout hole 11 becomes a predetermined pressure P or less that does not cause fracture (crack) in the rock.
(B) Although the artificial hydrodynamic gradient U can be gradually reduced as the injection of the grout material G progresses, the hydrodynamic gradient U is recovered by adjusting the control valve 22 of the drain hole 21 and the grout hole 11. Is kept below the predetermined pressure P, it is possible to avoid an increase in the injection pressure of the grout material G that may cause rock mass destruction (cracking).
(C) Since the grout hole 11 is maintained at a predetermined pressure P or less, the grout material G is also used in a deep layer under a high water pressure of, for example, about 10 MPa using the existing grout material injection device 15 having a relatively low pressure. Can be injected.

(D) The drilling positions of the grout hole 11 and the drain hole 21 are arbitrarily selected according to the shape of the spring generating geology 8, and an artificial hydrodynamic gradient U corresponding to the shape is formed to form the grout material G. Can penetrate. That is, the penetration direction of the grout material G can be controlled, and the grout material G can be prevented from penetrating to an unexpected place.
(E) Moreover, since the spring water of the spring water generation geology 8 is lowered by using clogging or hardening in the infiltration process of the grout material G due to the artificial hydraulic gradient U, it is used in the normal still water grout method. In addition to the cement-based grout material G, a low-alkali cement-based or clay-based grout material G having a slow curing rate can be used.

  FIG. 1A shows an embodiment in which the still water grout system of the present invention is applied when excavating a mine 6 of a geological disposal facility for radioactive waste as shown in FIG. The horizontal sectional view containing the mine shaft 6 of the deep ground layer 1 in the line II of FIG. 4 (B) is represented. In the illustrated example, after excavating the vertical shaft 4 or the inclined shaft 5 from the ground surface 2 to the deep ground layer 1, two of them are searched forward from the lower end of the vertical shaft 4 or the inclined shaft 5 in different horizontal directions while searching for the expected spring water generation layer 8. The main tunnel 6a and the disposal tunnel 6b are excavated simultaneously. For example, when the presence of the spring formation layer 8 is detected by forward exploration (for example, geophysical exploration, exploration drilling exploration, etc.) during excavation of the mine shaft 6b, spring water is generated by using the still water grouting method of the present invention as a pre-grouting method. By injecting the grout material G into the formation 8 and forming the water stop zone 19 at the planned position (excavation planned position) of the mine shaft 6b, the generation of the high-pressure spring 9 is prevented in advance (see FIG. 1B). ).

  Hereinafter, the still water grouting method and system of the present invention will be described with reference to the embodiment of FIG. 1, but the scope of the present invention is not limited to the deep underground layer 1 such as a geological disposal facility, but a high water pressure It can be widely applied to the construction of ordinary mountain tunnels and underground storage bases where spring water 9 can be generated. In addition, the still water grouting method of the present invention is not only used as a pre-grouting method, but also a post grouting method in which a grouting material G is injected into the surrounding spring water generating geology 8 after the spring water 9 is generated during excavation of the tunnel 6. Can also be used.

  First, at least a pair of boring holes 11 and 21 are drilled from the tunnel 6 of the deep ground layer 1 to the surrounding spring water generation geology 8, and one of the boring holes 21 is connected to a drainage device 25 to form a drain hole. The boring hole 11 is connected to the grout material injection device 15 to form a grout hole. The drilling positions (including the drilling direction and drilling depth; the same applies hereinafter) of the grout hole 11 and the drain hole 21 are the same as the shape of the spring generation geology 8 (for example, the strike direction and inclination of the crack). Any combination can be selected. As will be described later, in the present invention, an artificial hydrodynamic gradient U is formed between the grout hole 11 and the drain hole 21 to infiltrate the grout material G. By determining the drilling positions of the grout hole 11 and the drain hole 21, for example, the water stop zone 19 can be formed by infiltrating the grout material G along the traveling and inclination of the crack, and the grout material G is spring water. It is possible to prevent penetration into a place outside the generated geology 8.

  As shown in FIG. 1, the grout hole 11 and the drain hole 21 are preferably drilled so as to overlap with the planned tunnel position 7 where the tunnel 6 is planned to be excavated in the future. When constructing a geological disposal facility in the deep underground 1, there is a possibility that the borehole will become a radionuclide waterway in the future, and it is not desirable that the borehole remains in the rock. If the grout hole 11 and the drainage hole 21 are overlapped with the mine planned position 7 and drilled, the grouting hole 11 and the drainage hole 21 do not remain by excavation of the subsequent mineway 6, and there is no possibility of becoming a water channel. In the illustrated example, a drain hole 21 is drilled from the disposal tunnel 6b along the planned tunnel path 7 ahead, and a grout hole 11 is drilled from the main tunnel 6a along the tunnel planning position 7 parallel to the disposal tunnel 6b. doing. When the grout hole 11 and the drain hole 21 cannot be drilled so as to overlap the planned tunnel position 7, the backfilling of the bore holes 11 and 21 is necessary after the water stop grout is completed.

  In the embodiment of FIG. 1, one grout hole 11 and one drain hole 21 are provided for simplification of explanation, but a plurality of grout holes 11 from the tunnel 6 to the spring water generation geology 8 are provided. A water drain hole 21 may be provided. For example, grout holes 11 are drilled on both sides of one drain hole 21, and an artificial hydrodynamic gradient U is formed between the two grout holes 11 on both sides and the central drain hole 21. However, by allowing the grout material G to permeate at the same time, it is possible to form the water stop zones 19 that spread on both sides of the drain hole 21 in accordance with the shape of the spring water generation geology 8. Conversely, two drain holes 21 are drilled on both sides of one grout hole 11 to form artificial hydrodynamic gradients U between the central grout hole 11 and the drain holes 21 on both sides. However, it is also possible to simultaneously infiltrate the grout material G injected into the central grout hole 11 in different directions according to the shape of the spring water generation geology 8.

  The water stop grout system of the illustrated example includes a grout material injection device 15 and a pressure gauge 13 connected to the grout hole 11, a drainage device 25 and a control valve 22 connected to the drain hole 21, an injection device 15, a pressure gauge 13, And a control device 26 connected to the control valve 22. The system of the illustrated example includes an opening / closing valve (or control valve) 12 and a flow meter 14 for the grout hole 11 in the injection device 15, and the valve 12 and the flow meter 14 are connected to the control device 26. The flow meter 14 may be separated from the injection device 15 and connected to the control device 2. Further, the control valve 22 of the drain hole 21 can be included in the drainage device 25, and in this case, the control device 26 may be connected to the drainage device 25. In the illustrated example, the drainage hole 21 is also provided with a pressure gauge 23 for confirming the pressure of the deep ground layer 1, but the pressure gauge 23 of the drainage hole 21 is not essential to the present invention.

  FIG. 3 shows the difference in pressure head (dynamic gradient) generated between the grout hole 11 and the drain hole 21 when the control valve 22 of the drain hole 21 is gradually expanded while the valve 12 of the grout hole 11 is closed. An example of the change of U) is shown. In this example, there is no pressure head difference between the grout hole 11 and the drain hole 21 in a steady state where both the valve 12 of the grout hole 11 and the control valve 22 of the drain hole 21 are closed (initial stage). Head). However, by gradually increasing the opening degree of the control valve 22, the water head of the grout hole 11 is gradually lowered to the head 2, the water head 3, and the water head 4, and the moving water is between the grout hole 11 and the water drain hole 21. A gradient U can be formed. As described above, it is difficult to inject the grout material G under the high water pressure of the deep underground layer 1 where the spring water pressure is about 10 MPa, but the control valve 22 of the drain hole 21 is expanded as shown in FIG. If the head of the hole 11 is lowered, the grout material G can be injected using the existing injection device 15 having a relatively low pressure.

  For example, the pressure gauge 13 in the grout hole 11 is drained from the drain hole 21 by the drainage device 25 and the pressure slightly lower than a predetermined pressure (groutable pressure) P at which the grout material G can be injected by the control device 26 (for example, FIG. 3). After adjusting the control valve 22 of the drain hole 21 to the initial opening so as to become the water head 3), the injection device 15 is driven and the injection of the grout material G from the grout hole 11 is started. Alternatively, when there is a surplus in the amount of wastewater that can be treated by the drainage device 25, the control valve for the drainage hole 21 so that the pressure gauge 13 in the grout hole 11 is sufficiently lower than the predetermined pressure P (for example, the water head 4 in FIG. 3). The grout material G may be started by adjusting 22 to the initial opening. The initial opening degree of the control valve 22 can be determined in consideration of the amount of wastewater that can be treated by the drainage device 25 within a range where the pressure gauge 13 of the grout hole 11 is below a predetermined pressure P at which the grout material G can be injected. .

  The predetermined pressure P in the grout hole 11 may be a pressure at which the grout material G can be injected according to the injection pressure of the grout material injection device 15. For example, the initial opening degree of the control valve 22 of the drain hole 21 is adjusted so that the predetermined pressure P of the grout hole 11 becomes 1/2 to 1/3 of the injection pressure of the injection device 15. However, in the present invention, the grout material G injected into the grout hole 11 can be caused to flow by the artificially formed hydrodynamic gradient U. Therefore, it is necessary to push the grout material G at a pressure 2 to 3 times the external water pressure. If the pressure is about the same as the external water pressure, the grout material G can be expected to permeate into the spring generation geology 8 by the hydrodynamic gradient U. In this case, what is necessary is just to adjust the initial opening degree of the control valve 22 of the drain hole 21 so that the predetermined pressure P of the grout hole 11 becomes comparable to the injection pressure of the injection apparatus 15.

  The grout material G injected from the grout hole 11 penetrates the spring water generation geology 8 by the dynamic water gradient U and is sent to the drain hole 21 side. In the infiltration process, the water stop zone 19 is gradually formed in the spring water generation geology 8 due to the clogging effect of the grout material G or the hardening action of the grout material G. As the grout material G becomes clogged or hardens, the groundwater becomes difficult to flow, the hydrodynamic gradient U gradually decreases, and the pressure of the grout hole 11 can increase (for example, from the head 3 to the head 2). Such a pressure increase in the pressure gauge 13 can be detected by the control device 26. The control device 26 of the illustrated example expands the opening degree of the control valve 22 of the drain hole 21 in accordance with the pressure increase of the pressure gauge 13 and recovers the hydraulic gradient U, thereby reducing the grout hole 11 to a predetermined pressure P or less. Maintain and continue injection of grout material G. That is, in the conventional grouting method, the injection pressure of the grouting material G is increased according to the filling of the spring formation layer 8, but in the grouting method of the present invention, the injection pressure of the grouting material G is not increased. Since the injection of the grout material G is continued by increasing the amount of drainage from the hole 21, it is possible to avoid an increase in the injection pressure of the grout material G that can cause rock mass destruction (cracking).

  Alternatively, a drainage flow meter 24 is provided in the control valve 22 of the drain hole 21 as in the illustrated example, and the control device 26 reduces the drainage flow rate of the drainage flow meter 24 instead of the pressure increase of the pressure gauge 13 in the grout hole 11. It is also possible to recover the hydraulic gradient U by detecting and expanding the opening of the control valve 22 of the drain hole 21 according to the decrease in the drainage flow rate. For example, when the control valve 22 is reduced from the drainage flow rate at the initial opening degree, the pressure of the grout hole 11 is lowered by expanding the opening degree of the control valve 22 and maintaining the drainage flow rate at the initial opening degree. It is also effective to monitor both the pressure of the pressure gauge 13 and the drainage flow rate of the drainage flow meter 24 by the control device 26 and adjust the opening of the control valve 22 based on both the pressure and the drainage flow rate.

  When the grout material G is injected from the grout hole 11 but the pressure of the pressure gauge 13 in the grout hole 11 does not increase or the flow rate of the drainage flow meter 24 in the drain hole 21 does not decrease, the grout material G It is considered that the hydrodynamic gradient U is too large. In this case, the hydrodynamic gradient U can be reduced by reducing the initial opening of the control valve 22 within a range in which the pressure gauge 13 in the grout hole 11 is equal to or lower than the predetermined pressure P. Further, when it is difficult to reduce the opening degree of the control valve 22, as shown in the illustrated example, the grout material injection device 15 is provided with an adjusting device 16 that adjusts the viscosity or curing speed of the grout material G, and the viscosity of the grout material G Or increase the curing rate. For example, the proportion of the powder of the grout material G is adjusted by the adjusting device 16, or an appropriate viscosity adjusting agent is added to the grout material G. Alternatively, an appropriate curing rate adjusting agent may be added to the grout material G.

  The injection of the grout material G from the grout hole 11 is continued until the control valve 22 of the drain hole 21 is fully opened and the drain flow rate of the drain flow meter 24 of the drain hole 21 becomes a predetermined flow rate W or less. If the permeation characteristics of the water stop zone 19 decrease due to clogging or hardening of the grout material G, the drainage flow rate of the drainage hole 21 also decreases, but the permeation characteristics of the waterstop zone 19 are estimated to some extent from the drainage flow rate of the drainage hole 21. be able to. For example, the predetermined flow rate W when the water stop zone 19 has a desired permeation characteristic is obtained in advance, and the drainage flow rate is equal to or lower than the predetermined flow rate W even if the control valve 22 of the drain hole 21 is fully opened. It can be confirmed that the water-stopping zone 19 having the permeation characteristics can be formed.

  In this manner, the object of the present invention can be provided as “a still water grouting method and system capable of being constructed without destroying a rock in a deep layer of high water pressure”.

  In FIG. 2, a drain hole 21 is drilled from a predetermined part of the tunnel 6 a toward the spring generation geology 8, and a plurality of grout holes 11 a are formed around the drain hole 21 toward the spring generation geology 8. , 11b are drilled into a fan shape, and the grout material G is simultaneously permeated while forming an artificial hydrodynamic gradient U between the plurality of surrounding grout holes 11a, 11b and the central drain hole 21, respectively. The water stop grout construction method and system of the present invention are shown. According to such a grouting method, for example, when the spring water generation geology 8 is spread in a plane, the planar water stop zone 19 can be quickly and efficiently formed according to the shape. However, although the drain hole 21 is drilled so as to overlap with the planned tunnel position 7, the grout holes 11 a and 11 b that do not overlap with the planned tunnel position 7 can become water drains in the future. Need to backfill. In the illustrated example, one drain hole 21 is provided, but a plurality of drain holes 21 may be provided.

  Also in the illustrated system, as in the case of FIG. 1, the drain hole 21 is connected to the drainage device 25 and the control valve 22, and the plurality of grout holes 11a and 11b are connected to the grout material injection device 15 and the pressure gauge 13a, respectively. 13b. While draining from the drain hole 21 by the drainage device 25, the control device 26 allows the pressure gauges 13a, 13b of the grout holes 11a, 11b to be equal to or lower than a predetermined pressure P at which the grout material G can be injected. After adjusting the control valve 22 to the initial opening, the injection device 15 is driven to inject the grout material G from the grout holes 11a and 11b. Further, the control device 26 detects a pressure increase of the pressure gauges 13a and 13b in each of the grout holes 11a and 11b, and expands the opening of the control valve 22 of the drain hole 21 in accordance with the pressure increase, thereby each grout hole 11a. , 11b is maintained at a predetermined pressure P or lower and the injection of the grout material G is continued. As in the case of FIG. 1, the control valve 22 of the drain hole 21 is fully opened, and the injection of the grout material G is continued until the drainage flow rate of the drainage flow meter 24 is equal to or lower than the predetermined flow rate W. A water stop zone 19 having desired permeation characteristics can be formed in the generated geology 8.

It is explanatory drawing of one Example of the still water grout construction method by this invention. It is explanatory drawing of the other Example of the still water grout construction method by this invention. It is a graph which shows an example of the water pressure change of the grout hole according to the valve opening degree of the drain hole. It is explanatory drawing of the geological disposal facility of radioactive waste.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Deep underground layer (bedrock) 2 ... Surface 3 ... Ground facilities 4 ... Access shaft 5 ... Access slope 6 ... Tunnel 7 ... Tunnel planned position 8 ... Spring water generation geology 9 ... Spring water 11 ... Grout hole 12 ... Valve 13 ... Pressure gauge 14 ... Flow meter 15 ... Grout injection device 16 ... Grout adjustment device 19 ... Water stop zone (improved zone)
21 ... Drain hole 22 ... Control valve 23 ... Pressure gauge 24 ... Flow meter 25 ... Drainage device 30 ... Control device

Claims (8)

In the still water grouting method, which suppresses high water pressure springs that can occur during the construction of deep underground pits, grouting holes and drainage holes are drilled in the surrounding spring generation geology from the mine tunnel, and a pressure gauge and grouting material are injected into the grouting holes Connect the control valve and drainage device to the drain hole and connect the device, and gradually expand the control valve of the drain hole so that the pressure gauge of the grout hole is below the predetermined pressure lower than the spring water pressure. by driving the injection device after having adjusted injected grout, the pressure gauge by expanding the opening of the control valve according to the pressure rise in the pressure gauge grout holes by injection progression of the grout below the predetermined pressure Maintained water stop grout method under high water pressure. The water stop grout method according to claim 1, wherein a drainage flow meter is provided in the drain hole, and the control valve is opened according to a decrease in the drainage flow rate of the drainage flowmeter instead of or in addition to the pressure increase of the pressure gauge. Water stop grout method under high water pressure. 3. The still water grout method according to claim 2, wherein the control valve of the drain hole is fully opened and the injection of the grout material into the grout hole is continued until the drainage flow rate becomes a predetermined flow rate or less. Construction method. In the still water grouting method according to claim 2 or 3, when the effluent flow rate of the effluent flow meter is not reduced at the time of pouring the grouting material into the grouting hole, the viscosity or the curing rate of the grouting material is increased under high water pressure. Still water grout method. In a still water grouting system that suppresses high water pressure springs that can occur during the construction of deep underground tunnels, a pressure gauge and a grouting material injection device connected to the grouting holes drilled in the surrounding spring generation geology from the tunnels, and the generation of the springs The control valve and drainage device connected to the drainage hole drilled from the tunnel in the geology, and the initial opening degree where the control valve of the drainage hole is gradually expanded so that the pressure gauge of the grout hole is below a predetermined pressure lower than the spring pressure by expanding the opening of the control valve according to the pressure rise in the pressure gauge grout holes by injection progression drives the grout injection apparatus and said grout after having adjusted the control for maintaining the pressure gauge below the predetermined pressure A water stop grout system under high water pressure equipped with a device. 6. The water stop grout system according to claim 5, wherein a drainage flow meter is provided in the drain hole, and the control device is adapted to respond to a decrease in the drainage flow rate of the drainage flowmeter instead of or in addition to the pressure increase of the pressure gauge. A water stop grout system under high water pressure with the control valve opening widened. 7. The water stop grout system according to claim 6, wherein the control device continues to inject the grout material into the grout hole until the control valve of the drain hole is fully opened and the drainage flow rate becomes a predetermined flow rate or less. Lower still grout system. 8. The still water grout system according to claim 6, wherein the grout material injection device includes an adjusting device for adjusting a viscosity or a curing rate of the grout material.