JP5691079B2 - Evaluation method of rock condition by radon and evaluation device of rock condition by radon - Google Patents

Description

  The present invention relates to a method for evaluating a rock condition using a radon and a device for evaluating the condition of a rock, which use radon to evaluate the condition of the rock (the surface area of the rock, the state of spreading).

When isolating radioactive waste in the ground or storing carbon dioxide (CO ₂ ) underground, when verifying the collapse or collapse of a rock layer below the surface or the ground made of rock (rock) Furthermore, in the case of verifying the status of natural resources accumulated in the rock mass, it is an important matter to verify the void status (such as the surface area and the size of the gap) in the rock mass.

  Conventionally, in order to verify the rock gap, an ultrasonic measuring instrument is inserted between the hollows, the ultrasonic velocity is measured at different insertion depths, and the crack size is measured from the difference in ultrasonic velocity. (For example, refer to Patent Document 1). However, it is not possible to detect the surface area or the state of spread of cracks (rock gaps), and it is currently impossible to accurately evaluate the rock gap conditions.

  By the way, a small amount of uranium is contained in the rock of the bedrock, and radon as a decay product is released from the rock. Radon is an element that emits radiation with a predetermined half-life and leads to lead. Rocks have a gap, and radon is released from the surface of the rock's fluid gap. For this reason, it is considered that the gap condition including the surface area of the rock gap can be evaluated by measuring the amount of radon released.

Japanese Patent Laid-Open No. 10-318996

  The present invention has been made in view of the above situation, and a method for evaluating the rock gap condition by radon and the rock gap condition by radon that can accurately evaluate the condition of the rock gap in a predetermined area using radon. An object of the present invention is to provide an evaluation apparatus.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a method for evaluating a gap condition of a rock mass using a radon according to the first circulation of a fluid having a different external volume between a predetermined area inside the rock mass and the outside of the rock mass. The first circulation path of the fluid and the fluid, the theoretical value Fn of the rock mass radon flux is obtained, and the first radon concentration released to the fluid after circulating the fluid through the first circulation path over a first predetermined period [ Rn1] and the first radius r1 of the gap extension of the predetermined area inside the rock mass based on the first radon concentration [Rn1], the theoretical value Fn of the radon flux and the condition of the first circulation path, The second radon concentration [Rn2] released to the fluid after circulating the fluid through the second circulation path over a predetermined period is obtained, the second radon concentration [Rn2], the theoretical value Fn of the radon flux, and the second circulation path. Based on the situation, the second radius r2 of the gap extension of the predetermined area inside the rock mass is obtained, and the first radius r1 and the second radius r2 are obtained, and then the first radius r1 and the second radius r2 are assumed to be equal. It is characterized in that the width wn of the gap in the predetermined area is obtained.

  In the present invention according to claim 1, the first radius r1 is determined by the first radon concentration [Rn1] when the fluid is circulated through the first circulation path, the theoretical value Fn of the radon flux, and the state of the first circulation path. On the other hand, the second radius r2 is obtained from the second radon concentration [Rn2] when the fluid is circulated through the second circulation path, the theoretical value Fn of the radon flux and the state of the second circulation path, and the first Since the gap wn of the predetermined area inside the rock mass is obtained assuming that the radius r1 and the second radius r2 are equal, the situation of the gap in the predetermined area inside the rock mass can be evaluated based on the width wn, and the first circulation path and The condition of the gap can be accurately evaluated according to the spread of the gap of the path constructed by the second circulation path. Therefore, even if the initial radon concentration in the natural state is not in a radiation equilibrium state, that is, even if the radon concentration is not in a radiation equilibrium state due to the influence of boring excavation or the like, the radiation is surely emitted. The equilibrium radon concentration can be applied as the first radon concentration [Rn1].

  Therefore, it is possible to evaluate the condition (surface area) of the gap by obtaining the width wn of the gap in the state where the surface irregularities in the spread of the gap of the rock in the predetermined area are taken into account. It becomes possible to accurately evaluate the condition of the gap including the spread and the surface state of the gap.

  As a result, it becomes possible to accurately evaluate the condition of the rock gap in a predetermined area using radon.

  And the evaluation method of the gap condition of the rock mass by radon of the present invention according to claim 2 is the method for evaluating the gap condition of the rock mass by radon according to claim 1, wherein the fluid to be circulated is water. To do. According to a third aspect of the present invention, there is provided a method for evaluating a rock gap condition using a radon according to the present invention, wherein the first circulation path and the second circulation path are made of water. Including the container to be stored, the condition of the first circulation path includes the volume V1 of the container, the surface area S1 of the container, and the radon flux F1 of the container, and the condition of the second circulation path includes the volume V2 of the container, It includes a surface area S2 and a radon flux F2 of the container.

  In the present invention according to claim 2 and claim 3, by using radon released into water, it is possible to accurately evaluate the condition of the rock gap in a predetermined area. According to the third aspect of the present invention, the radius of r of the gap can be obtained using the volume V of the container, the surface area S of the container, and the radon flux F of the container, and the condition of the gap can be evaluated.

  According to the fourth aspect of the present invention, there is provided an apparatus for evaluating a gap condition of a rock mass according to a fourth aspect of the present invention, which is formed from the outside of the rock mass to the inside of the rock mass, and water is supplied from the outside of the rock mass to supply water into the rock mass. A first hole passage to be discharged, a second hole passage formed from the outside of the rock mass to the inside of the rock mass, water discharged from the first hole passage being collected inside the rock mass and sent to the outside of the rock mass, a first hole passage, A first circulation path that circulates water between the two hole passages and between the first external passages outside the rock mass, between the first hole passage and the second hole passage, and outside the rock mass, A second circulation path that circulates water between a second external path having a capacity different from that of the first external path, and a first hole path that collects water circulated by the first circulation path and the second circulation path. Evaluation means for evaluating the surface area of the rock gap between the second hole passage and The evaluation means includes a function for obtaining a theoretical value Fn of the radon flux of the rock mass, and a concentration of the first radon released into the first circulation path after circulating water through the first circulation path over a first predetermined period. A function of obtaining [Rn1], a function of obtaining the first radius r1 of the gap spread based on the first radon concentration [Rn1], the theoretical value Fn of the radon flux, and the state of the first circulation path, and a second predetermined The function of obtaining the concentration [Rn2] of the second radon released into the second circulation path after circulating water through the second circulation path over a period, the second radon concentration [Rn2], and the theoretical value Fn of radon flux And the function of obtaining the second radius r2 of the gap spread based on the situation of the second circulation path, and the first radius r1 and the second radius r2 are assumed to be equal between the first hole passage and the second hole passage inside the rock Gap width wn Characterized in that a function and obtaining.

  In the present invention according to claim 4, the first radius r1 is determined by the first radon concentration [Rn1] when the fluid is circulated through the first circulation path, the theoretical value Fn of the radon flux, and the state of the first circulation path. On the other hand, the second radius r2 is obtained from the second radon concentration [Rn2] when the fluid is circulated through the second circulation path, the theoretical value Fn of the radon flux and the state of the second circulation path, and the first Since the gap wn of the predetermined area inside the rock mass is obtained assuming that the radius r1 and the second radius r2 are equal, the situation of the gap in the predetermined area inside the rock mass can be evaluated based on the width wn, and the first circulation path and The state of the gap (for example, the surface area) can be accurately evaluated according to the spread of the gap of the path constructed by the second circulation path. Therefore, even if the initial radon concentration in the natural state is not in a radiation equilibrium state, that is, even if the radon concentration is not in a radiation equilibrium state due to the influence of boring excavation or the like, the radiation is surely emitted. By applying the equilibrium radon concentration as the first radon concentration [Rn1], the condition of the gap (eg, surface area) can be accurately evaluated.

  Therefore, it is possible to evaluate the condition (surface area) of the gap by obtaining the width wn of the gap in the state where the surface irregularities in the spread of the gap of the rock in the predetermined area are taken into account. It becomes possible to accurately evaluate the condition of the gap including the spread and the surface state of the gap.

  As a result, it becomes possible to accurately evaluate the condition of the rock gap in a predetermined area using radon.

  According to a fifth aspect of the present invention, there is provided the apparatus for evaluating the gap condition of a rock mass using radon according to the present invention, wherein the first external path is configured to supply water outside the bedrock. A first container to be stored, a pumping path for pumping water stored in the first container to the first hole passage, and a storage path for circulating the water sent from the second hole passage to the first container are provided. The second external path is sent from the second container for storing water outside the bedrock, the pumping path for pumping the water stored in the second container to the second hole path, and the second hole path. The first circulation path having the function of obtaining the first radius r1 of the gap spread in the evaluation means includes: a volume V1 of the first container; Evaluation means including surface area S1 of the container and radon flux F1 of the first container The situation of the second circulation path of the function for obtaining the second radius r2 of the gap spread includes the volume V2 of the second container, the surface area S2 of the second container, and the radon flux F2 of the second container. It is characterized by that.

  In the present invention according to claim 5, the radon released into water is used, and the volume R of the container, the surface area S of the container, and the radon flux F of the container are used to obtain the radius r of the gap, and the situation of the gap Can be evaluated.

  The method and apparatus for evaluating the rock gap condition using radon according to the present invention makes it possible to accurately evaluate the situation including the spread and surface area of the rock rock in a predetermined area using radon.

It is a whole block diagram of the evaluation apparatus of the crevice condition of the rock bed by radon concerning one example of an embodiment of the present invention. It is a key map explaining situation evaluation of a gap. It is a processing flowchart. It is a graph showing a time-dependent change of radon concentration.

  FIG. 1 shows an overall conceptual configuration of an apparatus for evaluating rock gap conditions using radon according to an embodiment of the present invention, FIG. 2 shows a concept when a gap width is evaluated by a disk model, and FIG. 3 shows the present invention. FIG. 4 shows a change in radon concentration over time, according to a processing flow of a method for evaluating a gap condition of a rock mass using radon according to an embodiment of the present invention.

  Based on FIG. 1, an apparatus for evaluating a rock gap condition using radon will be described.

  As shown in the figure, the rock mass 1 is provided with a first hole passage 2 that discharges water into the rock mass 1 by supplying water as a fluid from the outside. A discharge space 4 defined by the packer 3 is formed at the tip of the first hole passage 2, and the hole of the first hole passage 2 is closed by the packer 6. Water is pumped into the discharge space 4 from the outside of the rock mass 1 (outside the portion blocked by the packer 6) via the first rod 5.

  In this embodiment, the example of supplying water as a fluid from outside assuming the bedrock 1 in which groundwater exists is described. However, when applied to a bedrock in which there is no groundwater, air or non-fluid is used as the fluid. It is also possible to use an active gas.

  On the other hand, the bedrock 1 is provided with a second hole passage 7, an inflow space 9 defined by a packer 8 is formed at the tip of the second hole passage 7, and the hole of the second hole passage 7 is a packer 10. It is blocked. The water discharged from the discharge space 4 of the first hole passage 2 to the rock mass 1 flows into the inflow space 9 through the portion where the gap of the rock mass 1 is formed (spread spreading region: indicated by a dotted line in the figure). The water sent to the inflow space 9 is sent from the second rod 21 to the outside of the rock mass 1 (outside of the portion blocked by the packer 10).

  A circulation path 11 for circulating water between the first hole passage 2 and the second hole passage 7 is provided outside the bedrock 1. The circulation path 11 includes a first container 12 and a second container 22 that store water outside the bedrock 1. And the 1st path | route 25 which sends the water stored by the 1st container 12 to the 1st hole channel | path 2 as it is, and the water stored by the 1st container 12, and the water stored by the 2nd container 22 are sent together. A second path 26 is provided, and the first path 25 and the second path 26 are switched by a switching mechanism (not shown).

  A pump 13 is connected to the downstream of the junction of the first path 25 and the second path 26, and water is pumped to the first hole path 2 via the pumping pipe 14 (pumping path). In addition, a storage pipe 15 (storage path) for circulating the water sent from the second hole passage 7 to the container 12 is provided. That is, a route passing through the first route 25 is a first circulation route (a first external route: a pump 13, a pressure feeding tube 14, and a housing tube 15) provided with a first container (first container 12). A path passing through the two paths 26 is a second circulation path (second external path: pump 13, pressure feed pipe 14, and storage pipe 15) provided with a second container (first container 12 and second container 22). ing.

  In addition, as the first container and the second container, the capacity of the first container 12 can be configured to be variable. Further, as the first container and the second container, it is possible to connect the first container 12 and the second container 22 having different capacities in parallel.

  The water circulating through the circulation path 11, the first hole path 2, and the second hole path 7 is collected after being circulated through the first circulation path and after being circulated through the second circulation path, and is released into the water. The condition of the gap is evaluated by the evaluation means 16 on the basis of the density of the rock and the theoretical value Fn of the uranium flux of the rock in the rock. That is, the condition of the gap of the rock mass 1 in a predetermined area defined between the discharge space 4 of the first hole passage 2 and the inflow space 9 of the second hole passage 7 (spread spread, crack width, crack surface area) Is evaluated by the evaluation means 16.

  The evaluation means 16 includes a function for obtaining a theoretical value Fn of a rock mass radon flux (a function for storing a theoretical value Fn obtained in advance) and a first circulation path (first path) over a first predetermined period (for example, one year). And the function of obtaining the concentration [Rn1] of the first radon released into the first circulation route after circulating water through the route 25), the first radon concentration [Rn1], and the theoretical value Fn of the radon flux. And a function of obtaining the first radius r1 of the gap spread based on the state of the first circulation path.

  In addition, the evaluation unit 16 supplies water to the second circulation path (route via the second path 26) over a second predetermined period (for example, one year after the lapse of a fixed time after the end of the first predetermined period). Of the second radon released to the second circulation path after circulating [Rn2], the second radon concentration [Rn2], the theoretical value of the radon flux Fn, and the situation of the second circulation path Based on this, the second radius r2 of the gap spread is obtained.

  Then, in the evaluation means 16, assuming that the first radius r1 and the second radius r2 are equal, the width wn of the gap between the first hole passage 2 and the second hole passage 7 inside the rock (the rock gap in a predetermined area) is set. The gap condition based on the width wn is determined.

The derivation of the crack width w will be described with reference to FIG. It is assumed that a crack c having a width wn exists between the rock mass R1 and the rock mass R2, and the crack c having a width wn extends in a range of a disk model having a radius r. Radon is released from the surfaces of the rock mass R1 and the rock mass R2 to the crack c, and the released radon and the size of the crack c have the following relationship.

A _e is the number of radon atoms reaches equilibrium, A _t is the number of radon atoms at time t, lambda is the decay constant of radon, F is a radon flux in crevices surface. Here, if t is sufficiently larger than the half-life ( ²²² R is 3.8 days) (for example, about 10 times the half-life), radon reaches equilibrium, and the relationship of the following equation is established.

Therefore, from Equation 1 and Equation 2, the width w of the crack can be expressed by the following equation.

  That is, the width w of the crack can be estimated from the radon flux and the concentration of radon released from the rocks R1 and R2. In addition, the theoretical value can be calculated | required for radon flux based on the sample acquired from rock mass R1 and R2. The concentration of the released radon can be determined by, for example, collecting water containing radon in the crack and measuring the amount of radon (number of radiation tracks) using a solid radiation sensor or the like.

  The evaluation means 16 collects water after circulating water through the first circulation path (path through the first path 25) (after the first circulation), and the concentration of radon released into the first circulation path. [Rn1] is obtained, and the width wn1 (theoretical value) of the gap (crack) of the rock mass 1 is derived from the radon concentration [Rn1] and the theoretical value Fn of the radon flux by the calculation described in Equation 3.

  Based on the radon concentration [Rn1], the crack (gap) width wn1 and the state of the first path 25, the first radius r1 of the gap spread is obtained. The situation of the first path 25 when obtaining the first radius r1 includes the volume V1 of the first container 12, the surface area S1 of the first container 12, and the radon flux F1 of the first container 12.

  The evaluation unit 16 collects water after the water is circulated (after the second circulation) through the second circulation path (path through the second path 26) over the second predetermined period, and the second circulation path. The radon concentration [Rn2] released into the rock is calculated, and the width wn2 (theoretical value) of the gap (crack) of the rock mass 1 is calculated from the radon concentration [Rn2] and the theoretical value Fn of the radon flux by the calculation described in Equation 3. Is derived.

  Based on the radon concentration [Rn2], the crack (gap) width wn2 and the state of the second path 26, the second radius r2 of the gap spread is obtained. That is, the second radius r2 of the gap spread is obtained by circulating water through circulation paths having different capacities. The situation of the second path 26 when obtaining the second radius r2 is that the volume V2 of the container with the first container 12 and the second container 22 added, and the container with the first container 12 and the second container 22 added. And the radon flux F2 of the first container 12 and the second container 22 is included.

  The evaluation means 16 assumes that the first radius r1 and the second radius r2 are equal, and the width wn of the gap (crack) of the rock mass 1 is based on an equation (described later) for obtaining the first radius r1 and the second radius r2. Desired. In other words, after obtaining the first radius r1 and the second radius r2 based on the theoretical values of the width wn1 and the width wn2, the information on the volume, surface area, and radon flux of the container in each path is taken into account, The width wn of the gap between the first hole passage 2 and the second hole passage 7 (the rock gap in a predetermined area) is obtained. The condition of the gap is evaluated based on the obtained wn.

The first radius r1 of the spread of the gap is obtained by the first circulation, the second radius r2 of the spread in the same gap is obtained by the second circulation having a different capacity of the circulating water, and the first radius r1 and the second radius r2 are equal. The width wn of the gap between the first hole passage 2 and the second hole passage 7 inside the rock mass (the gap of the rock mass in a predetermined area) is obtained. For this reason, the surface area S (= 2πr ² ) of the gap can be evaluated by the first radius r1 and the second radius r2, and the width wn of the rock gap in a predetermined area can be accurately obtained.

  Therefore, even if the initial radon concentration in the natural state is not in a radiation equilibrium state, that is, even if the radon concentration is not in a radiation equilibrium state due to the influence of boring excavation or the like, the radiation is surely emitted. By applying the radon concentration in the equilibrium state as the first radon concentration [Rn1], the situation of the gap (for example, the surface area) can be accurately evaluated. For this reason, regardless of the initial radon concentration in the natural state, even if there are irregularities on the gap surface, the surface area S can be accurately evaluated in a state where the irregularities on the surface are taken into account. The width wn of the gap can be obtained, and the situation of the rock gap in a predetermined area can be accurately evaluated.

  A method for evaluating the condition of the gap (crack) using the above-described apparatus for evaluating the gap condition of the rock using radon will be described in detail with reference to FIGS.

In step S1, the radon flux of the rock of the rock mass 1 is measured indoors, and is set as the theoretical value Fn (Bq / m ² ) of the radon flux.

  Water circulation is started by the first path 25 (first circulation). A predetermined amount of water is pumped from the first rod 5 to the discharge space 4 of the first hole passage 2 by the pump 13, passed through the rock mass 1, and flows into the inflow space 9 of the second hole passage 7. The water that has flowed into the inflow space 9 is stored in the first container 12, and the water in the first container 12 is circulated through the first hole passage 2 by the pump 13. For example, water is circulated through the first hole passage 2, the second hole passage 7, and the circulation passage 11 (first passage 25) for one year.

As shown in FIG. 4, when the circulation of water is started with respect to the radon concentration [Rnn] (Bq / m ³ ) in the natural state (□), the circulation path 11 (only the first container 12 is removed) without radon release. The radon concentration decreases with time due to the volume of the flow path). After circulating water through the circulation path 11 (first path 25) for a predetermined period (for example, one year), the radon concentration becomes [Rn1] (Bq / m ³ ) (○ mark: [Rnn]> [Rn1 ]). When the circulation is finished, the radon concentration gradually increases and becomes a natural radon concentration [Rnn] (Bq / m ³ ) (marked with ■).

Water is injected after the first circulation, and the gap width wn1 (theoretical value) is obtained from the radon concentration [Rn1] (Bq / m ³ ) and the theoretical value Fn of the radon flux as shown in step S2 of FIG. 3). In step S3, a first radius r1 of the gap (fissure) is calculated. The first radius r1 (m) of the fissure is the radon concentration [Rn1] (Bq / m ³ ) of the water after circulation, the volume V1 (m ³ ) of the first container 12, and the surface area S1 of the first container 12 ( m ² ) and radon flux F1 (Bq / m ² ) of the first container 12 are obtained by the following mathematical formula 4.

As shown in FIG. 4, when the radon concentration [Rnn] (Bq / m ³ ) in the natural state is reached (marked with ■) after the completion of the first circulation, the second circulation is started by the second path 26. . As shown in FIG. 1, a predetermined amount of water is pumped from the first rod 5 to the discharge space 4 of the first hole passage 2 by the pump 13, and passes through the rock mass 1 to the inflow space 9 of the second hole passage 7. Let it flow. The water flowing into the inflow space 9 is accommodated in the first container 12 and the second container 22, and the water in the first container 12 and the second container 22 is circulated through the first hole passage 2 by the pump 13. For example, water is circulated through the first hole passage 2, the second hole passage 7, and the circulation passage 11 (second passage 26) for one year.

As shown in FIG. 4, when the circulation of water is started with respect to the radon concentration [Rnn] (Bq / m ³ ) in the natural state (marked with ■), the circulation path 11 (the first container 12 and the first container 12 without the radon release) is started. The radon concentration decreases with the passage of time due to the volume of the flow path that circulates the two containers 22. After circulating water through the circulation path 11 (second path 26) for a predetermined period (for example, one year), the radon concentration becomes [Rn2] (Bq / m ³ ) (● mark: [Rn1]> [Rn2 ]).

Water is injected after the second circulation, and the gap width wn2 (theoretical value) is obtained from the radon concentration [Rn2] (Bq / m ³ ) and the theoretical value Fn of the radon flux as shown in step S4 of FIG. 3). In step S5, a second radius r2 of the gap (fissure) is calculated. The second radius r2 (m) of the fissure is the radon concentration [Rn2] (Bq / m ³ ) of the water after circulation, the total volume V2 (m ³ ) of the first container 12 and the second container 22, Based on the total surface area S2 (m ² ) of the first container 12 and the second container 22 and the radon flux F2 (Bq / m ² ) of the first container 12 and the second container 22, the following formula 5 is used.

By calculating the first radius r1 (m) and the second radius r2 (m) of the crack, based on the first radius r1 (m) and the second radius r2 (m) (according to the spread of the crack) The surface area S (m ² ) is calculated from S = 2πr ² .

  After the first radius r1 (m) and the second radius r2 (m) are calculated, the first radius r1 (m) and the second radius r2 (m) are equal as shown in step S6 of FIG. The width wn (evaluation value) of the gap (crack) of the rock mass 1 is obtained by taking into account the volume, surface area, and radon flux information of the container in each path. In this case, it is assumed that the gap width wn1 and the gap width wn2 are also equal, and the width wn of the gap (crack) of the rock mass 1 reflecting the condition of the path is obtained.

That is, the width wn of the gap (crack) of the rock mass 1 in which the path condition is reflected is obtained by the following Equation 6.

As described above, since the water having different capacities is circulated to obtain the width wn of the gap between the first hole passage 2 and the second hole passage 7 inside the rock (the rock gap in a predetermined area), The surface area S (= 2πr ² ) of the gap can be evaluated by the first radius r1 and the second radius r2, and the width wn of the rock mass in a predetermined area is accurately obtained regardless of the initial radon concentration in the natural state. be able to. For this reason, it is possible to evaluate the surface area S of the cracks in a state where the surface irregularities in the spread of the gap are taken into account, and to evaluate the surface area of the gap including the surface state of the gap of the rock in a predetermined area, Using radon, it becomes possible to accurately evaluate the condition of rock gaps in a given area.

  In the above-described embodiment, the state of the first path 25 is calculated based on the volume V1 of the first container 12, the surface area S1 of the first container 12, and the radon flux F1 of the first container 12, and the second The condition of the path 26 includes the volume V2 of the container with the first container 12 and the second container 22 added, the surface area S2 of the container with the first container 12 and the second container 22 added, and the first container 12. And the radon flux F2 of the second container 22, but when actually evaluating the volume, surface area, and flux, for example, a pipe or pump other than a gap (gap of a rock in a predetermined area) 13. It may be necessary to include the volume / surface area and flux of the first hole passage 2 and the second hole passage 7 in the section separated by the packer. For the sake of convenience, these portions can be regarded as 0 as a slight value compared to the volume, surface area, and flux of the gap (rock gap in a predetermined area). When actually obtained, it is also possible to perform calculation by taking into consideration the actual volume, surface area, and flux depending on the situation of the tank and piping.

  INDUSTRIAL APPLICABILITY The present invention can be used in the industrial field of an evaluation method and an evaluation apparatus for a rock gap condition using radon that evaluates the condition (width, surface area) of the rock gap in a predetermined area using radon.

DESCRIPTION OF SYMBOLS 1 Bedrock 2 1st hole channel | path 3, 6, 8, 10 packer 4 discharge | release space 5 1st rod 7 2nd hole channel | path 9 inflow space 11 circulation path 12 1st container 13 pump 14 pumping pipe 15 accommodation pipe 16 evaluation means 21 1st 2 rod 22 2nd container 25 1st path | route 26 2nd path | route

Claims (5)

A first circulation path of fluid and a second circulation path of fluid having different capacities outside the rock are constructed between a predetermined area inside the rock and the outside of the rock,
Obtain the theoretical value Fn of rock mass radon flux,
Obtaining a first radon concentration [Rn1] released into the fluid after circulating the fluid in the first circulation path over a first predetermined period;
While obtaining the first radius r1 of the gap spread of the predetermined area inside the rock mass based on the first radon concentration [Rn1], the theoretical value Fn of the radon flux and the situation of the first circulation path,
Determining a second radon concentration [Rn2] released into the fluid after circulating the fluid in the second circulation path over a second predetermined period;
Based on the second radon concentration [Rn2], the theoretical value Fn of the radon flux, and the situation of the second circulation path, the second radius r2 of the gap extension of the predetermined area inside the rock is obtained,
After determining the first radius r1 and the second radius r2, the gap width wn of a predetermined area inside the rock is calculated assuming that the first radius r1 and the second radius r2 are equal. Evaluation method. In the evaluation method of the crevice condition of the bedrock by radon according to claim 1,
The fluid to be circulated is water. The method for evaluating a rock condition of a rock mass using radon. In the evaluation method of the crevice condition of the bedrock by radon according to claim 2,
The first circulation path and the second circulation path include a container in which water is stored,
The situation of the first circulation path includes the volume V1 of the container, the surface area S1 of the container, and the radon flux F1 of the container.
The condition of the second circulation path includes the volume V2 of the container, the surface area S2 of the container, and the radon flux F2 of the container. A first hole passage that is formed from the outside of the bedrock to the inside of the bedrock, and discharges water into the bedrock by supplying water from the outside of the bedrock;
A second hole passage formed from the outside of the rock mass to the inside of the rock mass, and water discharged from the first hole passage is collected inside the rock mass and sent to the outside of the rock mass;
A first circulation path for circulating water between the first hole path and the second hole path, and between the first external path outside the bedrock;
A second circulation path that circulates water between the first hole path and the second hole path and between the second external path outside the bedrock and having a capacity different from the first external path;
An evaluation means for collecting the water circulating through the first circulation path and the second circulation path and evaluating the surface area of the rock gap between the first hole passage and the second hole passage;
Evaluation means
The function to obtain the theoretical value Fn of the rock mass radon flux,
A function of determining the concentration [Rn1] of the first radon released into the first circulation path after circulating water through the first circulation path over a first predetermined period;
A function for obtaining the first radius r1 of the spread of the gap based on the first radon concentration [Rn1], the theoretical value Fn of the radon flux, and the state of the first circulation path;
A function of determining the concentration [Rn2] of the second radon released into the second circulation path after circulating water through the second circulation path over a second predetermined period;
A function of obtaining the second radius r2 of the gap spread based on the second radon concentration [Rn2], the theoretical value Fn of the radon flux, and the state of the second circulation path;
It is provided with a function to obtain the width wn of the gap between the first hole passage and the second hole passage inside the rock, assuming that the first radius r1 and the second radius r2 are equal. Evaluation device. In the evaluation apparatus of the gap condition of the rock mass by radon according to claim 4,
The first external route is
A first container for storing water outside the bedrock;
A pumping path for pumping water stored in the first container to the first hole path;
An accommodation path for circulating water sent from the second hole passage to the first container,
The second external route is
A second container for storing water outside the bedrock;
A pumping path for pumping water stored in the second container to the second hole path;
An accommodation path for circulating water sent from the second hole passage to the second container,
The situation of the first circulation path of the function for obtaining the first radius r1 of the gap spread in the evaluation means is:
A volume V1 of the first container, a surface area S1 of the first container, and a radon flux F1 of the first container;
The situation of the second circulation path of the function for obtaining the second radius r2 of the gap spread in the evaluation means is as follows:
A device for evaluating a gap state of a rock mass by radon, comprising: volume V2 of the second container, surface area S2 of the second container, and radon flux F2 of the second container.

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