JP4740180B2 - Method of burying chemical injection pipe for cleaning contaminated soil - Google Patents

Description

  The present invention relates to a method of burying a chemical solution injection pipe for injecting a chemical solution for purification into a contaminated soil layer in the ground so as to cross the contaminated soil layer.

  Conventionally, there has been known a method for purifying contaminated soil by injecting a cleaning chemical from a nozzle provided at the tip of an excavating tool while drilling a borehole so as to cross a contaminated soil layer in the ground by a curved boring method. (For example, refer to Patent Document 1). This method is applied when the pollutant is an organochlorine compound, and the purification chemical for purifying the contaminated soil is water mixed with iron powder. Organochlorine compounds in the contaminated soil layer are reduced and decomposed by iron powder to make them harmless.

  A soil purification method is also known in which contaminants such as heavy oil are decomposed by microorganisms. In this case, a liquid containing a nutrient salt for activating microorganisms is injected into the contaminated soil layer as a chemical solution for purification. Here, in the purification method using microorganisms, it is necessary to continuously inject a chemical solution containing a nutrient salt into the contaminated soil layer for a long period of time. Conventionally, a vertical hole reaching the contaminated soil layer from the ground surface is drilled, and a chemical solution is injected into the contaminated soil layer through the vertical hole. However, this method cannot be used when facilities exist on the ground surface above the contaminated soil layer. Therefore, the chemical solution injection pipe is buried in the ground so as to cross the contaminated soil layer, the chemical solution is supplied into the pipe, and the chemical solution is continuously injected into the contaminated soil layer from the injection holes formed in the axial direction of the pipe. It is desirable.

  By the way, as a purification method when the pollutant in the contaminated soil layer is a chemical substance such as benzene, conventionally, air pipes are buried below the contaminated soil layer, and air is ejected from holes formed in various locations in the axial direction of the pipe. Is made to flow from the lower side of the contaminated soil layer to the upper side, and the pollutant is recovered by being entrained by air in a collection unit embedded above the contaminated soil layer (see, for example, Patent Document 2). And in this thing, when embedding an air pipe, first, it passes through the lower part of the contaminated soil layer from the ground surface located on one side of the contaminated soil layer by a bending boring method using a drilling tool attached to the tip of the flexible rod. Drill a borehole that reaches the ground surface located on the other side of the contaminated soil layer, and then remove the drilling tool from the tip of the flexible rod exposed on the ground surface on the other side, where the diameter is larger than that of the drilling tool. After attaching a reamer and connecting an air pipe to this reamer, the bored hole is expanded by the reamer while pulling the flexible rod to the ground surface side, and the air pipe is drawn into this hole, and the contaminated soil layer An air pipe is buried below

Here, if a boring hole is drilled from the ground surface located on one side of the contaminated soil layer to the ground surface located on the other side of the contaminated soil layer across the contaminated soil layer, the above-described chemical solution is used in the same manner. An injection pipe can be buried across the contaminated soil layer. However, this method requires two steps of drilling a borehole with an excavating tool and expanding the borehole with a reamer. Not only drilling to the point where it crosses the contaminated soil layer, but also drilling by extending the borehole from the point where it has crossed the contaminated soil layer to the ground located on the other side of the contaminated soil layer Is necessary and time-consuming. Also, when the chemical injection pipe is pulled into the borehole, the chemical injection pipe rubs the inner surface (natural ground) of the borehole, and the ground is pushed into the injection hole formed in the chemical injection pipe and the injection hole is clogged. However, there is a possibility that poor injection of the chemical solution may occur.
JP 2000-135483 A JP 2004-5999 A

  In view of the above points, the present invention can easily embed a chemical injection pipe in a short construction period so as to cross a contaminated soil layer, and can prevent clogging of an injection hole formed in the chemical injection pipe. The problem is to provide a method for burying a chemical injection pipe for soil purification.

  In order to solve the above problems, the present invention is a method of burying a chemical injection pipe for injecting a chemical solution for purification into a contaminated soil layer in the ground so as to cross the contaminated soil layer, and a tip of a casing pipe Drilling a boring hole that crosses the contaminated soil layer with an excavating tool that is detachably attached to the tube, inserting a chemical injection pipe into the casing pipe after drilling the boring hole, and drilling after inserting the chemical injection pipe And a step of pulling out the casing pipe from the boring hole while leaving the tool in the ground.

  According to the present invention, after drilling the boring hole from the surface located on one side of the contaminated soil layer to the point where it crosses the contaminated soil layer, the chemical injection pipe is inserted into the casing pipe, and finally the casing pipe is By extracting from the boring hole, the chemical injection pipe can be embedded so as to cross the contaminated soil layer. Therefore, it is not necessary to extend the drilling hole from the point where the contaminated soil layer has been traversed to the ground surface located on the other side of the contaminated soil layer, and only one drilling operation is required. Shortening can be achieved. In addition, since the chemical injection pipe is inserted into the casing pipe, the chemical injection pipe rubs the inner surface (natural ground) of the boring hole and the earth and sand of the natural ground is pushed into the injection hole formed in the chemical injection pipe. Therefore, clogging of the injection hole can be prevented.

  If the drilling tool is fixedly attached to the tip of the casing pipe, when the casing pipe is pulled out from the borehole, it is pushed by the drilling tool that moves with the casing pipe, and the chemical injection pipe is also pushed out of the borehole. It will be. On the other hand, according to the present invention, since the excavation tool is removably attached to the tip of the casing pipe, the chemical injection pipe is inserted into the casing pipe so that the tip reaches the excavation tool, and then the casing pipe is moved in the axial direction. When pulled to the tail, the excavation tool and the casing pipe are separated. Therefore, the casing pipe can be pulled out from the boring hole with the excavation tool left in the ground. As a result, the chemical injection pipe remains in the borehole.

  By the way, in order to prevent the chemical liquid from being injected to a part of the contaminated soil layer, the internal space of the chemical liquid injection pipe is partitioned into a plurality of rooms by a plurality of partition members arranged at intervals in the pipe axis direction. It is desirable that the chemical solution is supplied to each room via a separate liquid supply hose so that the chemical solution is injected into the contaminated soil layer from the injection hole formed in the pipe wall on the outer periphery of each room. In this case, when the chemical solution injection pipe is constituted by a single continuous pipe, the insertion distance of the partition wall member from the pipe end portion becomes considerably long depending on the partition wall member. In order to insert the partition wall member at such a long distance, it is necessary to insert the partition wall member into the chemical solution injection pipe without receiving frictional resistance so much. It becomes difficult to ensure liquid tightness.

Therefore, liquid injection pipes, Ru is constructed by connecting a plurality of short pipes that are divided corresponding to the plurality of rooms strung in a state in which the inner fitting is allowed each partition wall member to an end of the short pipe. According to this, since the partition member is inserted at the end of the short pipe and the insertion distance is shortened, there is no problem even if the insertion frictional resistance of the partition member with respect to the short pipe is large. Therefore, the partition member can be tightly fitted to the end of the short pipe, and the liquid tightness between the short pipe and the partition member can be secured.

  Here, it is necessary to insert all the liquid supply pipes corresponding to all the rooms located in the pipe axial direction ahead of the partition member into each partition member. And when the individual hole which penetrates each liquid supply pipe is formed in a partition member, after inserting the end of each liquid supply pipe in each hole of a partition member, a partition member is fitted to a corresponding short length pipe It is necessary to slide a long distance with respect to the liquid supply pipe to the position, and the assembling work becomes troublesome.

  In order to solve such a problem, each partition member is formed of an elastic material, and a set in which all the liquid supply hoses corresponding to all the rooms located in the pipe axial direction ahead of the partition member are collectively inserted into each partition member. It is desirable that a hole and a split portion that is located at one place around the collecting hole and that divides the partition wall member in the circumferential direction are formed. According to this, the liquid supply pipe can be inserted into the partition wall member by storing the liquid supply pipe in the collecting hole from the outside in the radial direction with the split portion opened. Therefore, the liquid supply hose can be inserted into the partition member in the vicinity of the short pipe, and the partition member can be fitted into the end of the short pipe. Therefore, it is not necessary to slide the partition member from the terminal for a long distance with respect to the liquid supply pipe, and the assembling work is facilitated.

By the way, when the casing pipe is pulled out from the boring hole, a gap is formed between the inner surface of the boring hole and the outer peripheral surface of the chemical injection pipe. And if each room | chamber of a chemical | medical solution injection pipe connected via the space | gap on the outer side, the meaning which supplies a chemical | medical solution separately for every room will be lost. Therefore, a partition member that divides the gap formed between the inner surface of the boring hole and the outer peripheral surface of the chemical injection pipe into a plurality of regions in the pipe axis direction corresponding to the plurality of chambers of the chemical injection pipe is provided on the outer peripheral surface of the chemical injection pipe. that has been attached. According to this, each room | chamber of a chemical | medical solution injection pipe does not connect via the space | gap on the outer side, but the chemical | medical solution from each room is reliably inject | poured into each location of a contaminated soil layer.

  Referring to FIG. 1, reference numeral 1 denotes a contaminated soil layer in the ground. In order to purify the contaminated soil layer 1 using microorganisms, a chemical solution injection pipe 2 is embedded so as to cross the contaminated soil layer 1, and a chemical solution containing microorganisms and nutrient salts for activating microorganisms is stored in the chemical solution injection pipe 2. To the contaminated soil layer 1.

  With reference to FIG. 2, the embedding construction method of the chemical injection pipe 2 will be described. First, as shown in FIG. 2A, the excavation tool 4 attached to the tip of the flexible casing pipe 3 finishes traversing the contaminated soil layer 1 from the ground located on one side of the contaminated soil layer 1. The boring hole 5 is drilled by the bending boring method. Here, the tip of the excavation tool 4 is formed on an inclined surface. When the excavation tool 4 is rotated through the casing pipe 3, the excavation is straight, but when the excavation tool 4 is not rotated, the excavation direction is bent by a radial reaction force component acting on the inclined surface at the tip of the excavation tool 4. Then, after drilling straight up to a predetermined depth obliquely downward from the ground surface, the drilling direction is bent and leveled, and the boring hole 5 is drilled so as to cross the contaminated soil layer 1.

  After drilling the boring hole 5, as shown in FIG. 2 (b), the chemical solution injection pipe 2 is inserted into the casing pipe 3 so that the tip thereof reaches the excavation tool 4. Next, the casing pipe 3 is pulled out from the boring hole 5. Here, if the excavation tool 4 is fixedly attached to the tip of the casing pipe 2, when the casing pipe 2 is pulled out, it is pushed by the excavation tool 4 that moves together with the casing pipe 2, and the chemical injection pipe 2 is removed from the boring hole 5. It will be pushed out. Therefore, in this embodiment, the excavation tool 4 is attached to the tip of the casing pipe 3 so as to be freely inserted and removed. Therefore, when the casing pipe 3 is pulled in the axial direction, the excavation tool 4 and the casing pipe 3 are separated, and the casing pipe 3 can be pulled out from the boring hole 5 while leaving the excavation tool 4 in the ground. As a result, the chemical injection pipe 2 stays in the borehole 5 as shown in FIG. 1 and is buried so as to cross the contaminated soil layer 1.

  In addition, you may provide the joint with the operation part which connects the excavation tool 4 to the casing pipe 3 removably. In this case, when the tip of the chemical injection pipe 2 reaches the excavation tool 4, the operation portion of the joint is pushed by the chemical injection pipe 2, and the connection between the excavation tool 4 and the casing pipe 3 by the joint is released. To do.

  Next, the chemical solution injection pipe 2 will be described. As shown in FIG. 3, the internal space of the chemical liquid injection pipe 2 is partitioned into a plurality of chambers 22 by a plurality of partition members 21 arranged at intervals in the pipe axis direction. The chemical solution is supplied individually through the control unit 23. And a chemical | medical solution is inject | poured into the contaminated soil layer 1 from the injection hole 24 formed in the pipe wall of the outer periphery of each room | chamber 22. FIG. The injection hole 24 is covered with a nonwoven fabric 25 wound around the outer peripheral surface of the pipe in order to prevent earth and sand from entering the injection hole 24.

  In addition, when the chemical solution injection pipe 2 is inserted into the boring hole 5 without the casing pipe 3, the chemical solution injection pipe 2 rubs the inner surface (natural ground) of the boring hole 5. Then, the earth and sand of the natural ground are pushed into the nonwoven fabric 25 to cause clogging of the nonwoven fabric 25. Furthermore, the nonwoven fabric 25 is peeled off and the earth and sand are pushed into the injection hole 24, and the injection hole 24 may be clogged. Thereby, poor injection of the chemical solution occurs. However, in the present embodiment, since the chemical liquid injection pipe 2 is inserted into the casing pipe 3 as described above, the chemical liquid injection pipe 2 does not rub the inner surface of the boring hole 5, and the above-described problems do not occur.

  Further, when the casing pipe 3 is pulled out from the boring hole 5, a gap is formed between the inner surface of the boring hole 5 and the outer peripheral surface of the chemical solution injection pipe 2. And if each room | chamber 22 of the chemical | medical solution injection pipe 2 connected via the space | gap on the outer side, the meaning which supplies a chemical | medical solution separately for every room 22 will be lost. Therefore, in the present embodiment, a plurality of gaps between the inner surface of the boring hole 5 and the outer peripheral surface of the chemical solution injection pipe 2 are divided into a plurality of regions in the pipe axis direction corresponding to the plurality of chambers 22 of the chemical solution injection pipe 2. The partition member 26 is attached to the outer peripheral surface of the chemical solution injection pipe 2. The partition member 26 is configured by laminating two annular plates made of an elastic material such as rubber, and the outer peripheral portion thereof is elastically pressed against the inner surface of the boring hole 5 to ensure the sealing performance between the regions. I am doing so. The partition member may be of a balloon type that expands and contracts, and after the casing pipe 3 is pulled out, the partition member may be expanded by supplying fluid such as air thereto.

  By the way, when the chemical solution injection pipe 2 is constituted by a single continuous pipe, the insertion distance of the partition member 21 from the end portion of the pipe becomes considerably long depending on the partition member 21. In order to insert the partition member 21 at such a long distance, the partition member 21 needs to be inserted into the chemical solution injection pipe 2 without receiving frictional resistance so much. As a result, the partition member 21 cannot be tightly fitted inside the chemical solution injection pipe 2, and it becomes difficult to ensure liquid tightness between the partition member 21 and the chemical solution injection pipe 2.

  Therefore, in the present embodiment, the joint 27 is formed in a state in which the plurality of short pipes 2a made of vinyl chloride divided corresponding to the plurality of rooms 22 are fitted into the end portions of the respective short pipes 2a with the respective partition wall members 21 fitted therein. The medicinal solution injection pipe 2 is configured by being connected in a daisy chain. According to this, since the partition member 21 is inserted at the end of the short pipe and the insertion distance becomes extremely short, there is no problem even if the insertion frictional resistance of the partition member 21 with respect to the short pipe 2a is large. Therefore, the partition member 21 can be tightly fitted in the short pipe 2a, and the liquid tightness between the short pipe 2a and the partition member 21 can be secured.

  Furthermore, the chemical solution injection pipe 2 has a certain degree of flexibility by connecting the plurality of short pipes 2a in a daisy chain to form the chemical solution injection pipe 2. Therefore, the chemical injection pipe 2 can be easily inserted even when the boring hole 5 has a bent portion. A cap 2b is attached to the tip of the leading short pipe 2a. Moreover, the two short pipes 2a 'on the tail end side in FIG. 1 are provided to push the short pipe 2a for injecting the chemical solution into the contaminated soil layer 1, and no chemical solution is supplied to the inside thereof.

  In the present embodiment, each partition member 21 is made of an elastic material such as rubber. Then, as shown in FIG. 4, each partition member 21 has a collection hole 21 a through which all the liquid supply hoses 23 corresponding to all the chambers 22 located in the pipe axial direction ahead of the partition member 21 are inserted. A split portion 21b that is located at one location around the hole 21a and that divides the partition wall member 21 in the circumferential direction is formed. According to this, the liquid supply pipe 23 can be accommodated in the collecting hole 21 a from the outside in the radial direction with the split portion 21 b opened, and the liquid supply hose 23 can be inserted into the partition wall member 21. Therefore, the liquid supply hose 23 can be inserted through the partition wall member 21 in the vicinity of the short pipe 2a, and the partition wall member 21 can be fitted into the end of the short pipe 2a. Therefore, it is not necessary to slide the partition member 21 with respect to the liquid supply hose 23 from the terminal for a long distance, and the assembling work is facilitated.

  The gap between the liquid supply hoses 23 in the collecting hole 21a is closed with a caulking agent 21c. In addition, the partition wall member 21 fitted in the leading short pipe 2a has a small number of liquid supply hoses 23 inserted therethrough and a short distance from the tip of the liquid supply hose 23. You may form the hole penetrated separately.

  After the chemical liquid injection pipe 2 is buried, the chemical liquid is supplied to the respective liquid supply hoses 23 from the different liquid supply sources. In this embodiment, each liquid supply source is composed of each liquid tank 6 installed on the ground surface as shown in FIG. Each liquid supply hose 23 is connected to a valve 6 a provided at the bottom of each liquid tank 6. Thereby, the chemical | medical solution in each liquid tank 6 is supplied to each room | chamber 22 of the chemical | medical solution injection | pouring pipe 2 via each liquid supply hose 23 by gravity.

  By the way, it is also possible to supply a chemical solution to each liquid supply hose 23 with each pump as a liquid supply source. However, this consumes electric power, and the running cost increases when the chemical solution is continuously injected over a long period of time, such as half a year. On the other hand, this embodiment is advantageous in reducing running cost without consuming electric power.

  The injection of the chemical liquid is started in a state where the liquid levels of the chemical liquids in all the liquid tanks 6 are aligned at a predetermined level. Here, the contaminated soil layer 1 is not homogeneous, and a place where a chemical solution is easy to enter and a place where it is difficult to enter are mixed. A room located in a place where the chemical solution in the contaminated soil layer 1 is difficult to enter because the descending speed of the liquid level of the chemical solution in the liquid tank 6 connected to the room 22 located in the place where the chemical solution in the contaminated soil layer 1 is easy to enter is increased. The descending speed of the liquid level of the chemical solution in the liquid tank 6 connected to 22 is slow. Therefore, the situation of each location of the contaminated soil layer 1 can be grasped based on the descending speed of the liquid level of the chemical solution in each liquid tank 6.

  After grasping the situation of each part of the contaminated soil layer 1 in this way, the supply pressure of the chemical liquid to each room 22 is individually managed by adjusting the liquid level of the chemical liquid in each liquid tank 6. Thereby, a chemical | medical solution can be inject | poured into each location of the contaminated soil layer 1 appropriately. That is, by making the liquid level of the liquid tank 6 connected to the room 22 located in the place where the chemical solution is difficult to enter relatively high and increasing the chemical solution supply pressure to the room 22, the chemical solution is difficult to enter. Can reliably inject the drug solution.

  Moreover, it is also possible to inject | pour a high performance chemical | medical solution into the location where the contamination density | concentration of the contaminated soil layer 1 is high there. Thus, the contaminated soil can be efficiently purified by individually managing the supply pressure of the chemical solution and the type of the chemical solution according to the situation of each location of the contaminated soil layer 1.

  In addition, adjustment of the liquid level of the chemical solution in each liquid tank 6 may be performed manually or automatically using a float valve or the like.

Explanatory drawing which shows the soil purification system using the chemical | medical solution injection pipe embed | buried by the construction method of embodiment of this invention. (A) The figure which shows the drilling completion state of the boring hole in the construction method of embodiment, (b) The figure which shows the insertion completion state of the chemical | medical solution injection pipe in the construction method of embodiment. The longitudinal cross-sectional view of the principal part of the chemical | medical solution injection pipe of embodiment. The transverse cross section of the partition member of an embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Contaminated soil layer, 2 ... Chemical solution injection pipe, 2a ... Short pipe, 21 ... Partition member, 21a ... Collecting hole, 21b ... Split part, 22 ... Room, 23 ... Liquid supply hose, 24 ... Injection hole, 26 ... Partition Member, 3 ... casing pipe, 4 ... excavation tool, 5 ... boring hole.

Claims (3)

A method of burying a chemical solution injection pipe for injecting a chemical solution for purification into a contaminated soil layer in the ground so as to cross the contaminated soil layer,
The internal space of the chemical liquid injection pipe is partitioned into a plurality of rooms by a plurality of partition members arranged at intervals in the pipe axis direction, and the chemical liquid is supplied to each room via a separate liquid supply hose. The chemical solution is injected into the contaminated soil layer from the injection hole formed in the outer pipe wall, and the chemical solution injection pipe has a plurality of short pipes divided into a plurality of rooms at the end of each short pipe. In what is configured to be connected in a daisy chain with each partition member fitted inside,
Drilling a borehole that crosses the contaminated soil layer with a drilling tool that is removably attached to the tip of the casing pipe;
Inserting the chemical injection pipe into the casing pipe after drilling the boring hole;
A method of embedding a chemical injection pipe for purifying contaminated soil, comprising: a step of pulling out a casing pipe from a boring hole with an excavation tool left in the ground after the chemical injection pipe is inserted. Each partition member is formed of an elastic material, and each partition member has a collection hole through which all the liquid supply hoses corresponding to all the chambers located in the pipe axial direction ahead of the partition member are inserted. 2. The method for embedding a chemical solution injection pipe for purifying contaminated soil according to claim 1, wherein a split portion is formed at one location around the hole and divides the partition wall member in the circumferential direction. A method of burying a chemical solution injection pipe for injecting a chemical solution for purification into a contaminated soil layer in the ground so as to cross the contaminated soil layer,
A plurality of partition members are attached to the outer peripheral surface of the chemical injection pipe to divide the gaps formed between the inner surface of the boring hole and the outer peripheral surface of the chemical injection pipe into a plurality of regions in the pipe axis direction corresponding to the plurality of chambers. In what
Drilling a borehole that crosses the contaminated soil layer with a drilling tool that is removably attached to the tip of the casing pipe;
Inserting the chemical injection pipe into the casing pipe after drilling the boring hole;
A method of embedding a chemical injection pipe for purifying contaminated soil, comprising: a step of pulling out a casing pipe from a boring hole with an excavation tool left in the ground after the chemical injection pipe is inserted.

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