JP3616892B2 - Water-sealed underground tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water-sealed underground tank suitable for storing, for example, liquefied petroleum gas at different storage pressures.
[0002]
[Prior art]
Conventionally, as one method for storing liquefied gas such as liquefied petroleum gas (LPG), there is a technique using a water-sealed underground tank. This technology basically excavates and forms a horizontal cavity that extends horizontally below the groundwater level in the ground consisting of rock, and stores liquefied gas using this cavity as an underground tank. The liquefied gas is confined in the underground tank by the underground water pressure in the ground.
[0003]
When storing a high storage pressure in a water-sealed underground tank, as shown in FIG. 4, not only the underground tank 1 is provided at a deep position in the rock G where the groundwater pressure becomes high, but the water sealing effect is further enhanced. For this purpose, a horizontal water curtain 2 is provided above the underground tank 1. The horizontal water curtain 2 includes a water-sealed tunnel 3 extending along the longitudinal direction of the underground tank 1 and a plurality of horizontal water-sealed borings 4, 4,... Extending horizontally from the water-sealed tunnel 3 at predetermined intervals. It consists of and. When water oozes out from the horizontal water curtain 2 into the rock G, the crack is closed, and the water permeability of the rock G around the underground tank 1 can be reduced and the groundwater pressure can be increased, thereby enhancing the water sealing effect. It is like that.
[0004]
By the way, when a plurality of underground tanks 1 as described above are provided adjacent to each other, and the underground tanks 1A and 1B adjacent to each other store different types of storage pressure such as propane and butane, the following problems are caused. Will occur. That is, since the groundwater pressure by the horizontal water curtain 2 does not act on the bedrock G1 between the underground tanks 1A and 1B, the groundwater pressure in this portion is the groundwater pressure around the underground tanks 1A and 1B and the underground tanks 1A and 1B. It becomes lower than the internal pressure. Then, for example, when the internal pressure P1 of the underground tank 1A is lower than the internal pressure P2 of the underground tank 1B, the internal pressure P1 of the underground tank 1A leaks from the bedrock G1 to the underground tank 1B side due to the pressure difference, and finally the underground tank The liquefied gas stored in 1A will be mixed in the underground tank 1B.
[0005]
In order to avoid such a problem, as a method of storing different storage pressures in the underground tanks 1A and 1B adjacent to each other, there is a method of increasing the distance between the underground tanks 1A and 1B.
[0006]
Moreover, as shown in FIG. 5, there is also a method of providing a vertical water curtain 4 between the underground tanks 1A and 1B. The vertical water curtain 5 includes a water-sealed tunnel 6 extending in the horizontal direction and a vertical water-sealed boring 7 excavated so as to extend vertically downward from the water-sealed tunnel 6 at predetermined intervals. And the water which oozes out from the vertical water curtain 5 to the crack of the surrounding rock mass G exhibits a water sealing effect between the underground tanks 1A and 1B, and is stored in the underground tank 1B and the liquefied gas stored in the underground tank 1A. This prevents mixing with the liquefied gas.
[0007]
[Problems to be solved by the invention]
However, the conventional water-sealed underground tank as described above has the following problems.
First, as shown in FIG. 4, in order to prevent the storage materials from mixing between the underground tanks 1A and 1B by increasing the distance between the underground tanks 1A and 1B, The underground tanks 1A and 1B must be separated by 500m or more. Moreover, in order to obtain a certain effect, it is necessary to grasp in detail the crack condition existing in the rock G between the underground tanks 1A and 1B, but the investigation requires enormous costs and time, and the investigation is detailed. However, it is practically difficult to completely grasp the crack of the rock mass G. Moreover, if the space between the underground tanks 1A and 1B is increased, the area of the land necessary for providing the underground tanks 1A and 1B will naturally increase, and both the cost and construction period will increase, and there will be restrictions on location. In some cases, it may be difficult to install the underground tanks 1A and 1B.
[0008]
Further, as shown in FIG. 5, in the method of installing the vertical water curtain 5, in order to increase the reliable water sealing effect, there are still many methods for determining the position of the vertical water curtain 5 and the pitch of the vertical water sealing boring 7. Need for investigation and analysis. Moreover, when the vertical water curtain 5 is installed, the amount of water flowing into the underground tanks 1A and 1B increases as compared with the case of the horizontal water curtain 2 alone. The water flowing into the underground tanks 1A and 1B needs to be pumped up and discharged, but there is a problem that the maintenance cost for this will be forever required as long as the underground tanks 1A and 1B are in service. . Furthermore, this problem becomes more prominent as the pitch of the vertical water-sealed boring 7 is narrowed to enhance the water-sealing effect.
[0009]
The present invention has been made in consideration of the above points, and an object of the present invention is to provide a water-sealed underground tank that can provide a reliable water-sealing effect at low cost and in a short construction period.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, two water-sealed underground tanks that are continuous in the horizontal direction are constructed in the ground with a space therebetween , and a plurality of vertical borings are arranged between the two underground tanks. vertical water curtain comprising Te is constructed, between the two underground tanks and該鉛straight water curtain, together with the two underground tanks are arrayed spaced at a pitch which is defined along the direction in which each successive A plurality of grout holes, each filled with grout material and provided in a substantially columnar shape, are constructed, and the plurality of vertical borings are mutually connected when viewed from a horizontal direction perpendicular to the direction in which the two underground tanks are continuous. It is formed so that it may be located in the intermediate part of an adjacent grout hole .
[0011]
The invention according to claim 2 is the water-sealed underground tank according to claim 1, wherein each of the grout holes is excavated downward from a water-sealed tunnel excavated so as to extend in the horizontal direction. It is a feature.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, first and second embodiments of a water-sealed underground tank according to the present invention will be described with reference to FIGS. 1 to 3.
[0014]
[First embodiment]
As shown in FIGS. 1 and 2, for example, two underground tanks 10 </ b> A and 10 </ b> B are constructed at a predetermined depth in the rock G. These underground tanks 10 </ b> A and 10 </ b> B are formed by hollowing out the bedrock G or using natural cracks, and are of a horizontal type that is continuous in a horizontal direction over a predetermined length. For example, propane is stored in the underground tank 10A constructed at a deeper position, and butane is stored in the other underground tank 10B.
[0015]
A horizontal water curtain 11 is provided above each of the underground tanks 10A and 10B. Each horizontal water curtain 11 includes a water seal tunnel 12 and a horizontal water seal boring 13. The water seal tunnel 12 is provided so as to extend horizontally over the entire length of the underground tanks 10A and 10B at a position above the underground tank 10A or 10B and shifted laterally. The horizontal water-sealed borings 13, 13,... Are excavated and formed to extend in the horizontal direction from the water-sealed tunnel 12 toward the underground tanks 10A, 10B at predetermined intervals in the length direction of the water-sealed tunnel 12. ing.
[0016]
In the water seal tunnel 12, a plurality of grout holes 14 are formed by boring so as to extend vertically downward from the water seal tunnel 12 at predetermined intervals in the length direction. The grout hole 14 is filled with a grout material 15. The grout material 15 flows into the crack of the surrounding rock mass G from the grout hole 14 and closes it.
[0017]
A vertical water curtain 17 is provided between the underground tanks 10A and 10B. The vertical water curtain 17 vertically extends from the water seal tunnel 18 between the underground tanks 10 </ b> A and 10 </ b> B at a predetermined interval in the length direction of the water seal tunnel 18 extending in the horizontal direction along the water seal tunnel 18. It is comprised from the vertical water seal boring 19 bored toward.
[0018]
Here, as shown in FIG. 2, each vertical water-sealed boring 19 has a plan view with respect to the intermediate positions of the grout holes 14 and 14 adjacent to each other along the extending direction of the water-sealed tunnel 12. Are provided at positions shifted laterally. As a result, the grout holes 14, 14,... And the vertical water-sealed borings 19, 19,... Are arranged in a staggered manner along the direction in which the underground tanks 10A, 10B are continuous.
[0019]
In the underground tanks 10 </ b> A and 10 </ b> B having such a configuration, a water sealing effect is obtained by water leaching from the horizontal water curtain 11. Then, between the underground tanks 10A and 10B, the grout holes 15 formed at predetermined intervals are filled with the grout material 15 to close the cracks in the surrounding rock mass G, and thereby the grout holes arranged in line. A high water sealing effect can be exhibited in a substantially columnar range centering on 14. Moreover, since the vertical water-sealed boring 19 of the vertical water curtain 17 is arranged in the vicinity of the intermediate position between the adjacent grout holes 14, 14, the crack of the rock G between the grout holes 14, 14 is blocked. Thus, a water sealing effect can be obtained at this portion. These grout holes 14 and the vertical water curtain 17 can obtain a high water sealing effect between the underground tanks 10A and 10B and prevent the stored items (for example, propane and butane) from being mixed. Yes.
[0020]
In the underground tanks 10A and 10B described above, the grout holes 14, 14,... Filled with the grout material 15 are arranged between the water-sealed underground tanks 10A and 10B. And the water sealing effect can be acquired by these grout holes 14, and it can prevent that a store thing mixes between underground tank 10A, 10B. Further, a vertical water curtain 17 is provided between the underground tanks 10A and 10B, and the vertical water seal boring 19 of the vertical water curtain 17 is located between the adjacent grout holes 14 and 14. This further enhances the water sealing effect. In this way, since the space between the underground tanks 10A and 10B can be made smaller than before, the required area is reduced, the cost and construction period are shortened, and in a narrow site that could not be installed conventionally. It is possible to install underground tanks 10A and 10B. Further, by providing the grout holes 14, 14,... Between the vertical water curtain 17 and the underground tanks 10A, 10B, the amount of water entering the underground tanks 10A, 10B from the vertical water curtain 17 is reduced, and the drainage cost is reduced. Can be achieved.
[0021]
Further, each grout hole 14 is excavated downward from the water seal tunnel 12 of the horizontal water curtain 11. Thereby, when the grout hole 14 is excavated, it is not necessary to excavate a new tunnel, and since the water-sealed tunnel 12 can be used, an increase in construction cost can be minimized.
[0022]
[Second Embodiment]
Next, a second embodiment of the water-sealed underground tank according to the present invention will be described. In the second embodiment described below, the components common to the first embodiment are denoted by the same reference numerals and the description thereof is omitted.
[0023]
As shown in FIG. 3, for example, two underground tanks 20 </ b> A and 20 </ b> B are each constructed at a predetermined depth in the rock G, and a horizontal water curtain 21 is provided above the underground tanks 20 </ b> A and 20 </ b> B. Each horizontal water curtain 21 is provided such that the water seal tunnel 22 extends horizontally above the central axis of the underground tanks 20 </ b> A and 20 </ b> B, and the horizontal water seal bores 23, 23,. At a predetermined interval in the length direction, the structure is formed by excavation so as to extend horizontally from the water seal tunnel 22 toward both sides thereof.
[0024]
Further, between the underground tanks 20A and 20B, a water-sealed tunnel 25 extending in the horizontal direction and vertical water bored vertically downward from the water-sealed tunnel 25 at predetermined intervals in the length direction of the water-sealed tunnel 25. A vertical water curtain 27 composed of a sealed bowling 26 is provided.
[0025]
Then, the grout holes 28A and 28B are bored in the water seal tunnel 25 at predetermined intervals in the length direction so as to extend obliquely downward from the water seal tunnel 25 toward the underground tanks 20A and 20B on both sides. Is formed. The grout holes 29A and 28B are filled with a grout material 29. The grout material 29 flows from the grout holes 28A and 28B into the cracks in the surrounding rock mass G, thereby closing the cracks around the grout holes 28A and 28B.
[0026]
Here, the vertical water-sealed boring 26 and the grout holes 28 </ b> A and 28 </ b> B are formed so as to be alternately positioned in the direction along the water-sealed tunnel 25. As a result, the vertical water-sealed boring 26 is positioned at an intermediate portion between the grout holes 28A and 28B adjacent to each other.
[0027]
Also in the underground tanks 20A and 20B having the above-described configuration, the grout holes 28A and 28B are provided between them, whereby a water sealing effect can be obtained. The effect similar to underground tank 20A, 20B in a form can be show | played. And since these grout holes 28A and 28B can also be excavated from the water seal tunnel 25, construction cost can be minimized.
[0028]
In addition, in the said 1st or 2nd embodiment, the kind of substance stored in underground tank 10A, 10B, 20A, 20B is not ask | required at all.
In addition, as for water for obtaining a water sealing effect in the horizontal water curtains 11 and 21 and the vertical water curtains 17 and 27, natural ground water may be used, or water may be supplied artificially. Also good.
Further, the shape of the underground tanks 10A, 10B, 20A, 20B, the configuration of other parts, and the like are not limited in any way without departing from the gist of the present invention. In addition, the pitch and inclination angle of the grout holes 14, 28A, 28B, the type of the grout materials 15 and 29 to be filled, etc. may be any as long as the required water sealing effect can be obtained. Furthermore, if a sufficient water-sealing effect can be obtained with only these grout holes 14, 28A, 28B, the horizontal water curtains 11, 21, the vertical water curtains 17, 27, etc. are eliminated, and water is discharged only at natural groundwater pressure. It is good also as a structure sealed.
[0029]
【The invention's effect】
As described above, according to the water-sealed underground tank according to claim 1, two water-sealed underground tanks that are respectively continuous in the horizontal direction are constructed in the ground with an interval therebetween, and the two underground tanks A vertical water curtain in which a plurality of vertical borings are arranged is constructed between the vertical water curtain and the two underground tanks, and the two underground tanks are defined along a continuous direction. A plurality of grout holes arranged in a substantially column shape are formed by being spaced apart and arranged at a predetermined pitch, and the plurality of vertical borings are connected to the two underground tanks. When viewed from the horizontal direction orthogonal to the direction, the structure is formed so as to be located in the middle part of the grout holes adjacent to each other .
The grouting material filled in each grouting hole closes the cracks in the surrounding ground, so that each grouting hole arranged in this way and the surrounding columnar area have a water-sealing effect. Thus, it is possible to reliably prevent the stock from mixing. Moreover, since the distance between the two underground tanks can be reduced, the required area is reduced, the cost and construction period can be shortened, and it is possible to install in a narrow site that could not be installed conventionally. . Furthermore, since the water sealing effect of the underground tank is enhanced by the above configuration, the amount of water entering the underground tank is reduced, and the drainage cost can be reduced. In addition, depending on the ground conditions, the horizontal water curtain and the vertical water curtain can be reduced. Curtains can be eliminated.
Moreover, between adjacent grout holes can be complemented by vertical boring, and the above-mentioned effect can be made more remarkable by improving the water sealing property.
[0030]
According to the water-sealed underground tank according to claim 2, each grout hole is excavated downward from a water-sealed tunnel excavated to extend in the horizontal direction. Thereby, when excavating a grout hole, it is not necessary to excavate a new tunnel, and since a water-sealed tunnel can be used, an increase in construction cost can be minimized.
[Brief description of the drawings]
FIG. 1 is an elevational sectional view showing a first embodiment of a water-sealed underground tank according to the present invention.
2 is a cross-sectional plan view of FIG. 1. FIG.
FIG. 3 is an elevational sectional view showing a second embodiment of the water-sealed underground tank according to the present invention.
FIG. 4 is an elevational sectional view showing an example of a conventional water-sealed underground tank.
FIG. 5 is an elevational sectional view showing another example of a conventional water-sealed underground tank.
[Explanation of symbols]
10A, 10B, 20A, 20B Underground tank 14, 28A, 28B Grout hole 15, 29 Grout material 19, 26 Vertical water seal boring

Claims (2)

Two water-sealed underground tanks, each running horizontally, are built in the ground at an interval,
Between the two underground tanks, a vertical water curtain in which a plurality of vertical borings are arranged is constructed,
Between the vertical water curtain and the two underground tanks, the two underground tanks are spaced apart from each other at a predetermined pitch along the continuous direction, and each is filled with grout material to form a substantially columnar shape. A plurality of grout holes provided in the
The water seal characterized in that the plurality of vertical borings are formed so as to be positioned at intermediate portions of grout holes adjacent to each other when viewed from a horizontal direction orthogonal to a direction in which the two underground tanks are continuous. Formula underground tank. The water-sealed underground tank according to claim 1, wherein each of the grout holes is excavated downward from a water-sealed tunnel excavated so as to extend in a horizontal direction. .

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