JP2019020304A - Method for specifying position of penetration part - Google Patents

Abstract

To specify the position of a penetration unit where a contaminated substance is to diffuse.SOLUTION: The method for specifying the position of a penetration part is applied to a ground G where there is a low permeable layer G2 including a vertically extending penetration part 20, an upper permeable layer G1 is on the upper surface of the lower permeable layer, and a lower permeable layer G3 is on the lower surface of the low permeable layer G2. The method specifies the position of the penetration part 20 by injecting water into the upper permeable layer G1 or the lower permeable layer G3 and detecting the position of warm water in the lower permeable layer G3 or in the upper permeable layer G1.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for specifying a position of an infiltration portion.

  Patent Document 1 listed below discloses a purification method for purifying a hardly permeable layer and a contaminated part formed across the first permeable layer and the second permeable layer disposed above and below the hardly permeable layer. In this purification method, after identifying the location of the contaminated part by excavation, etc., an underground barrier wall that surrounds the contaminated part from three sides is constructed, and a nutrient supply well and a pumping well are constructed in the part surrounded by the underground barrier wall. doing.

JP 2005-177658 A

  In the purification method of Patent Document 1, the position of the contaminated portion formed over the first permeable layer, the second permeable layer, and the hardly permeable layer is specified by excavation, but the contaminated portion formed in the hardly permeable layer. That is, when the infiltrating portion where the contaminant penetrates from the first permeable layer to the second permeable layer is thin, it is difficult to specify the position of the water channel by excavation.

  In view of the above facts, the present invention has an object to identify the position of a permeation portion that becomes a diffusion path of a contaminant.

  The method for specifying the position of the infiltration part according to claim 1 is used for a ground having an upper permeable layer on an upper surface of a low permeable layer in which an osmotic part extending in the vertical direction exists, and having a lower permeable layer on a lower surface of the low permeable layer, A tracer is injected into the upper water permeable layer or the lower water permeable layer, and the position of the infiltration portion is specified from the position of the tracer detected by the lower water permeable layer or the upper water permeable layer.

  If there is a contaminant in the upper permeable layer or the lower permeable layer, the contaminant reaches the lower permeable layer or the upper permeable layer through the permeation portion of the low permeable layer sandwiched between the upper permeable layer and the lower permeable layer. For this reason, it is necessary to specify the position of the permeation part and perform processing such as sealing or purifying, but since the upper water-permeable layer is on the upper surface of the low water-permeable layer, the position of the permeation part is not easy to identify. Absent.

  Therefore, in the method for specifying the position of the permeation portion according to claim 1, the tracer is injected into the upper permeable layer or the lower permeable layer, and the position of the osmosis portion is specified from the position of the tracer detected by the lower permeable layer or the upper permeable layer. Thereby, the position specifying operation of the permeation portion is simplified.

  The method for specifying the position of the infiltration part according to claim 2 is characterized in that hot water having a temperature higher than groundwater is injected as the tracer into the lower permeable layer, and the temperature of the groundwater is measured by a plurality of temperature sensors arranged at intervals in the upper permeable layer. Is detected.

  In the method for specifying the position of the infiltration part according to claim 2, it can be specified that the infiltration part exists below the arrangement position of the temperature sensor that detects the temperature of the relatively high groundwater.

  According to a third aspect of the present invention, there is provided a method for specifying the position of the infiltration portion, wherein water is pumped from the upper water permeable layer.

  In the method for specifying the position of the infiltration portion according to claim 3, since the water is pumped from the upper permeable layer, the warm water easily penetrates into the upper permeable layer through the osmosis portion. For this reason, compared with the case where water is not pumped from the water permeable layer, the position of the permeation portion can be quickly identified.

  According to the present invention, it is possible to specify the position of a permeation portion that becomes a diffusion path of a contaminant.

(A) is an elevational sectional view showing a state in which pollutants are diffused into the upper water permeable layer in the ground to which the method for specifying the infiltration portion according to the embodiment of the present invention is applied. It is an elevation sectional view showing the state where it penetrated into the penetration part of a permeable layer. It is an elevation sectional view showing the state where the pollutant has diffused into the lower permeable layer in the ground to which the method for specifying the infiltration portion according to the embodiment of the present invention is applied. (A) is an elevational sectional view showing a state where an injection well is constructed in the lower permeable layer and a thermocouple is embedded in the upper permeable layer, in the method for specifying the infiltration portion according to the embodiment of the present invention, (B) FIG. 3 is an elevational sectional view showing a state where hot water is injected from an injection well into a lower permeable layer. (A) is an elevational sectional view showing a state in which groundwater warmed by warm water injected into the lower permeable layer has penetrated into the permeable portion of the low permeable layer, in the method for specifying the osmotic portion according to the embodiment of the present invention, (B) is an elevational sectional view showing a state in which the groundwater heated by the hot water injected into the lower permeable layer has reached the upper permeable layer. It is an elevation sectional view showing the modification which built the pumping well in the upper permeable layer in the infiltration part position specifying method concerning the embodiment of the present invention. It is an elevation sectional view showing the modification which built the horizontal investigation hole in the upper permeable layer in the infiltration part position specifying method concerning the embodiment of the present invention.

(ground)
As shown in FIG. 1 (A), the ground G to which the infiltration portion position specifying method according to the embodiment of the present invention is applied is a low tangent surface that is in contact with the upper permeable layer G1 that is the surface layer ground and the lower surface of the upper permeable layer G1. A water permeable layer G2 and a lower water permeable layer G3 in contact with the lower surface of the low water permeable layer G2 are provided.

  The upper permeable layer G1 and the lower permeable layer G3 are formed from sandy soil and are aquifers through which groundwater can flow, and the low permeable layer G2 is formed from viscous soil and is a water-impervious layer from which groundwater does not flow easily. In addition, the low water-permeable layer G2 should just be a layer whose water permeability is lower than the upper water-permeable layer G1 and the lower water-permeable layer G3.

  The low water permeable layer G2 is formed with a permeation portion 20 extending in the vertical direction and penetrating from the upper surface to the lower surface of the low water permeable layer G2. The infiltration portion 20 is a crack or gap in the viscous soil formed in the low water permeable layer G2, and is formed of sandy soil having a higher permeability than the cavity (in the absence of earth and sand) or surrounding viscous soil. Compared to other clay soils, it has a high water permeability and allows water to flow through.

  The infiltration part 20 is a thing in which traces such as piles, wells, and boreholes at the time of ground investigation remain when building a building on the ground G, in addition to naturally formed objects such as groundwater and gas ejection holes. . In FIG. 1A, the position represented by reference numeral GL represents the ground surface, and the position represented by reference numeral WL represents the groundwater level.

(Pollutant)
In such ground G, the pollutant E generated from the pollution source 10 is flowed by the groundwater and diffuses into the upper permeable layer G1. Moreover, as shown in FIG. 1 (B), it penetrates into the permeation part 20 in the low water permeability layer G2. Furthermore, it diffuses into the lower water permeable layer G3 as shown in FIG. Moreover, it gradually permeates the viscous soil around the permeation portion 20 in the low water permeability layer G2.

  In this way, the contaminated ground GE in which the pollutant E diffuses is formed across the permeation portion 20 and the lower permeable layer G3 in the upper permeable layer G1, the low permeable layer G2.

(Positioning method of penetrating part)
The infiltration portion position specifying method according to the embodiment of the present invention is a method for specifying the position of the infiltration portion 20 that is a path through which the contaminant E diffuses from the upper permeable layer G1 to the lower permeable layer G3 in the contaminated ground GE.

  In order to specify the position of the infiltration portion 20, first, as shown in FIG. 3A, an injection well 30 is provided at an arbitrary location in a portion where the pollutant E is detected by a soil contamination investigation or the like or a portion around it. To construct. The injection well 30 is constructed such that the tip reaches the lower water permeable layer G3.

  Then, a plurality of thermocouples 32 are embedded in the upper water permeable layer G1. The thermocouple 32 is a temperature sensor that can detect the temperature of groundwater in the upper water permeable layer G1, and a plurality of thermocouples 32 are arranged in the front-rear direction of the paper in addition to the left-right direction of the paper in FIG. Each thermocouple 32 is connected to a measuring device (not shown) by a lead wire 32A, and the temperature at each point of the upper water permeable layer G1 can be measured.

  Next, as shown in FIG. 3B, hot water is injected from the injection well 30 into the lower permeable layer G3. Hot water having a temperature higher than that of the groundwater in the lower permeable layer G3 and the upper permeable layer G1 is used. Thereby, in the lower water permeable layer G3, the groundwater around the injection well 30 is mixed with warm water and warmed. On the other hand, the low water permeable layer G2 above the lower water permeable layer G3 has lower water permeability than the lower water permeable layer G3, and therefore, it is difficult for warm water to diffuse and to be heated.

  In addition, the area | region shown with the code | symbol H in FIG.3 (B) has shown the groundwater (henceforth the groundwater H) warmed by mixing the warm water and the groundwater which were inject | poured from the injection well 30. FIG. The warm water injected from the injection well 30 is an example of a tracer in the present invention.

  If injection of warm water from the injection well 30 to the lower permeable layer G3 is continued, the groundwater H heated as shown in FIG. 4 (A) permeates into the inside of the infiltration portion 20, and as shown in FIG. 4 (B). It diffuses into the upper water permeable layer G1.

  At this time, in the upper water permeable layer G1, since the groundwater H warmed from the permeation part 20 is diffused, the temperature detected by the thermocouple 32 is higher in the part near the permeation part 20 than in the far part. That is, since the thermocouples 32B, 32C, and 32D in FIG. 4B have a thermocouple 32B <32C <32D, the detected temperature of the groundwater H is the thermocouple 32B> 32C> 32D. It is.

  Although the position of the infiltration portion 20 cannot be confirmed from the ground, the temperature detected by each thermocouple 32 can be measured by a measuring device connected by a lead wire 32A. For this reason, by specifying the thermocouple 32 that has detected the highest temperature, it is possible to specify the thermocouple 32 that is closest to the infiltration portion 20. Thereby, the position of the penetration part 20 can be specified.

  In addition, in order to measure the position of the infiltration portion 20 more accurately, a thermocouple 32 is added near the thermocouple 32B that has detected the highest temperature. A more accurate position can be known from the temperature indicated by the added thermocouple 32.

(Action / Effect)
According to the method for specifying the position of the infiltration portion of the present embodiment, the position of the infiltration portion 20 formed in the low water permeability layer G2 that cannot be visually recognized from the ground can be specified. Thereby, for example, the permeation part 20 can be prevented from penetrating into the permeation part 20 by sealing the permeation part 20 with a ground improvement material such as cement or fluidized concrete. If the pollutant E does not permeate the permeation portion 20, it is possible to prevent the pollutant E from diffusing into the lower water permeable layer G3.

  Further, if a purifying agent is injected into the infiltration portion 20, the contaminant E in the infiltration portion 20, the upper water permeable layer G1, and the lower water permeable layer G3 can be purified. Alternatively, if the purifying agent is injected into the upper water permeable layer G1 or the lower water permeable layer G3, the purifier penetrates the lower water permeable layer G3 or the upper water permeable layer G1 through the osmotic portion 20, so that the osmotic portion 20, the upper water permeable layer G1. And the contaminant E of the lower water permeable layer G3 can be purified.

  Further, for example, in a situation where the pollutant E is generated in the ground G having high water permeability, there is a case where the low water permeability layer G2 is artificially constructed in the ground G in order to suppress the diffusion of the pollutant E. . At this time, it is necessary to construct the low water permeability layer G2 seamlessly over a predetermined range. That is, it is necessary to construct the low water permeability layer G2 so as not to form the permeation part 20.

  However, since the low water-permeable layer G2 cannot be visually recognized from the ground, it is difficult to recognize even if the permeation part 20 is formed. Therefore, according to the position specifying method of the infiltration portion of the present embodiment, the presence or absence of the infiltration portion 20 can be specified in the constructed low water permeability layer G2 or the low water permeability layer G2 in the middle of construction. And when the penetration part 20 is formed, since the place can be specified, it can process appropriately using an improvement material etc.

  In addition, in this embodiment, although the pumping equipment is not provided in the upper water permeable layer G1, embodiment of this invention is not restricted to this. For example, as shown in FIG. 5, a pumping well 34 may be provided in the upper permeable layer G1. If the pumping well 34 is provided in the upper permeable layer G1, the groundwater H warmed by the hot water injected from the injection well 30 is drawn up by the pumping well 34 and easily penetrates into the infiltration portion 20. For this reason, compared with the case where the pumping well 34 is not provided, the position of the osmosis | permeation part 20 can be pinpointed rapidly.

  Moreover, in this embodiment, although the thermocouple 32 is embed | buried directly in the upper water permeable layer G1, embodiment of this invention is not restricted to this. For example, a plurality of horizontal survey holes 36 as shown in FIG. 6 (a plurality in the front-rear direction in FIG. 6) may be provided, and the thermocouple 32 may be installed therein.

  The horizontal survey hole 36 is formed in the upper permeable layer G1 by, for example, free boring capable of excavating the ground G along a straight line and a curved line. The thermocouple 32 is inserted into the horizontal inspection hole 36 at a predetermined interval and backfilled with earth and sand as necessary. A polyethylene pipe or the like may be drawn into the horizontal survey hole 36. If the thermocouple 32 is arranged inside the polyethylene pipe at a predetermined interval and is filled with water, a place where the temperature of the groundwater H is high can be specified by measuring the temperature change of the water heated by the groundwater H. . Alternatively, the temperature of the groundwater H can be measured by fixing a thermocouple outside the polyethylene pipe.

  In the present embodiment, hot water having a temperature higher than that of groundwater is injected as a tracer from the injection well 30 to the lower permeable layer G3. However, the embodiment of the present invention is not limited thereto. For example, cold water having a temperature lower than that of ground water may be injected. In this case, in the upper water permeable layer G1, the thermocouple 32 embedded near the infiltration portion 20 detects a lower temperature than the thermocouple 32 embedded far away. For this reason, by specifying the thermocouple 32 that has detected the lowest temperature, it is possible to specify the thermocouple 32 that is closest to the infiltration portion 20. Thereby, the position of the penetration part 20 can be specified.

  Further, instead of hot water or cold water, a fluorescent dye (eosin, uranin, rhodamine, etc.) may be injected from the injection well 30 into the lower water permeable layer G3. In this case, a groundwater sampling tube is buried in the upper permeable layer G1 instead of the thermocouple, and the fluorescence intensity of the groundwater collected by the sampling tube is measured with a fluorescence measuring instrument.

  At this time, the fluorescence intensity of groundwater collected from a position close to the infiltration portion 20 is greater than the fluorescence intensity of groundwater collected from a position far away. For this reason, it is possible to specify the sampling tube closest to the infiltration portion 20 by specifying the sampling tube from which the groundwater from which the highest fluorescence intensity has been detected is specified. Thereby, the position of the penetration part 20 can be specified.

  Alternatively, a non-fluorescent dye or pigment may be used instead of such a fluorescent dye. In this case, the concentration of these dyes and pigments may be measured instead of the fluorescence intensity.

  Further, a gas such as oxygen or carbon dioxide may be injected from the injection well 30 to the lower water permeable layer G3 as a tracer. In this case, a place where the gas concentration is high can be specified by burying a gas detector for detecting these gases in the upper water permeable layer G1 or installing it on the ground surface. Thereby, the position of the penetration part 20 can be specified.

  Moreover, you may inject | pour air as a tracer from the injection well 30 to the lower water permeable layer G3. In this case, if the upper permeable layer G1 is excavated to the groundwater level to expose the water surface, the position of the infiltration portion 20 can be identified from the location where many bubbles appear on the water surface. Or even if it does not excavate the upper water permeable layer G1, the ground surface is covered with a non-breathable cover, and the position of the infiltration part 20 can be specified from the place where an air pocket is generated in the lower part of the cover.

  Further, the injection well 30 is not necessarily used as a means for injecting the tracer into the lower water permeable layer G3. For example, the underground water may be warmed by burying a tubular body in which warm water or water vapor circulates in the lower permeable layer G3. The tracer in this case is “heat” generated from the tube.

  In this embodiment, hot water as a tracer is injected from the injection well 30 to the lower water permeable layer G3. However, a purifier for the pollutant E may be added to this hot water. By adding the purifying agent to the warm water, the lower permeable layer G3, the upper permeable layer G1, and the osmotic portion 20 can be purified in parallel with the operation of specifying the position of the osmotic portion 20.

  Furthermore, in this embodiment, warm water, that is, a tracer is injected into the lower water permeable layer G3 and detected by the upper water permeable layer G1, but the embodiment of the present invention is not limited thereto. For example, a tracer may be injected into the upper permeable layer G1 and detected by the lower permeable layer G3. In this case, for example, a crack is formed in the lower water permeable layer G3 by a hydraulic crushing method or the like, and a detector suitable for each tracer such as a thermocouple is embedded in the crack. Thus, embodiments of the present invention can be implemented in various ways.

20 Infiltration part 32 Thermocouple (temperature sensor)
G Ground G1 Upper permeable layer G2 Low permeable layer G3 Lower permeable layer

Claims (3)

There is an upper permeable layer on the upper surface of the low permeable layer in which there is an infiltration portion extending in the vertical direction, and it is used for the ground having the lower permeable layer on the lower surface of the low permeable layer,
A penetrating part position specifying method for injecting a tracer into the upper water permeable layer or the lower water permeable layer and specifying the position of the penetrating part from the position of the tracer detected by the lower water permeable layer or the upper water permeable layer.   2. The infiltration part according to claim 1, wherein hot water having a temperature higher than groundwater is injected as the tracer into the lower permeable layer, and the temperature of the groundwater is detected by a plurality of temperature sensors arranged at intervals to the upper permeable layer. Location method.   The infiltration portion position specifying method according to claim 2, wherein water is pumped from the upper permeable layer.