JP2006342621A - Excavating casing, square hole excavating method, decontaminated wall constructing method in contaminated ground, and contaminated ground decontaminating/replacing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently carry out excavation of a square hole without waste, to thereby achieve saving in labor, reduction of construction costs, and shortening of a construction period. <P>SOLUTION: There is provided an excavating casing 1 which is formed of a square steel pipe 3 or by combining the square steel pipe 3 with a U-shaped steel member 16. A square hole excavating method is carried out by using the excavating casing 1, and removing the ground G in the excavating casing 1 by means of an auger screw 4, a clamshell bucket 7, etc. Further by driving the excavating casings 1 connected to each other or overlapping each other to some extent, into the ground, a groove-like square hole 2 or a planar square hole 2 can be excavated, and the square hole excavating method is applied to a decontaminated wall constructing method in contaminated ground or a contaminated ground decontaminating/replacing method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention provides a contaminated ground in which a purification wall is constructed between the contaminated ground and the surrounding ground in order to prevent contaminants discharged from the contaminated source from penetrating into the ground where the contaminated source exists and flowing out to the surrounding ground through groundwater or the like. Concerning purification wall construction method.
Furthermore, the present invention is to excavate and remove the contaminated soil in the contaminated ground that is contaminated with the pollutant and spread in a planar shape, and fill the rectangular ground generated by the excavation with a good quality soil to refill the contaminated ground. It is related with the purification / replacement method of contaminated ground to be replaced by and purified.

  For example, construction work to construct a purification wall between the contaminated ground and the surrounding ground to prevent contaminants discharged from the chemical factory from seeping into the ground of the chemical factory site and flowing out to the surrounding ground through groundwater, etc. Has been done. In the construction, as shown in Patent Documents 1 and 2 and Non-Patent Document 1 below, a casing for excavation with a circular cross section is used, and by excavating the ground, a circular reference hole H is formed as shown in FIG. It is formed. Then, every time the reference hole H is formed, it is backfilled with the purifying material, and then the excavating casing is dug while appropriately overlapping, excavated, and backfilled with the purifying material. By repeating this, a groove-like connecting wall 102 is formed in which the reference hole H is connected and backfilled with the purifying material.

  The connecting wall 102 has a minimum wall thickness formed in the overlap portion. Therefore, the connecting wall 102 is formed so as to ensure the wall thickness required for the purification wall at the overlap portion. In other words, the connecting wall 102 is a thick wall that occupies most of the part that exceeds the wall thickness originally required for the rectangular purification wall 105, and has a structure that is wasteful as much as will be described later. Yes. The purification material is a purification material such as soil, sand, gravel, etc., or a mixture of these with a solidifying agent such as cement. The purification material is poured into the reference hole H each time, cured, and solidified. The connecting wall 102, that is, the purification wall 105 is constructed.

In this case, when a rectangular purification wall 105 having a width of 1 m, a length of 160 m, and a depth of 10 m is constructed using a circular excavation casing 104 having a diameter of 1.8 m, the required excavated soil volume V is taken as an example. in is a 1600 m ³ in 1m × 10m × 160m, actual excavated soil volume W is about 2874M ³ becomes at 0.9m × 0.9m × 3.14 × 10m × 113, Yohori amount U is W-V The excavation loss rate S is 17.6 m ³ , and U ÷ V is about 79.6%. Accordingly, the ground is excavated by an excess amount U corresponding to A, B, and C in FIG. 16, resulting in waste of construction labor and an increase in construction period.

  In constructing the purification wall 105, the reference hole H1 that is the starting end (the left end in FIG. 16) is first excavated, and the reference hole H1 is filled with the purification wall material such as soil and sand, and then the circular excavation is performed. Pull out the casing 104 upward. Then, according to the above set conditions, the circular excavation casing 104 is again driven at a position shifted by 1.42 m to form the next reference hole H2. In this case, the portion indicated by D in FIG. 16 in the previously filled purification wall material is re-excavated and taken out, resulting in waste of work and the purification wall material. In the same manner, each time the circular excavation casing 104 is sequentially driven in a predetermined connection direction at a pitch of 1.42 m, the above work and the purification wall material are wasted. The amount used also reaches a considerable amount.

  On the other hand, for contaminated ground that has been permeable and contaminated with contaminants, excavate and remove the contaminated soil in the contaminated ground, and fill the rectangular holes created by the excavation with high quality soil. Replacement work is being done. In this case, so-called open excavation has been carried out when the depth of contamination is shallow or when there is no groundwater or the like in the ground. In addition, when the contaminated section has a simple shape such as a rectangular parallelepiped shape, the ground has been excavated by using earth retaining and supporting works.

  However, the above open excavation cannot be performed when the depth of contamination is deep or when the contaminated section has a complicated shape, or when the impervious layer is thin and it is impossible to secure the earth retaining / supporting construction. Therefore, a circular excavation casing 104 as used in the case of constructing the purification wall 105 is used, and as shown in FIG. 17, a connection wall 102 is formed in which a large number of circular reference holes H are connected in a planar shape. It was. In this case, taking a case where a contaminated soil in a rectangular parallelepiped shape having a width of 10 m, a depth of 10 m, and a depth of 10 m is replaced with high quality soil using a circular excavation casing 104 having a diameter of 1.8 m, the excavation loss rate S is about 70.4%.

  Accordingly, the ground is excavated by an amount corresponding to the amount of extra moat U that is hatched outside the rectangular area 103 to be replaced, and the reference hole H in the rectangular area 103 is overlapped. However, since the high quality soil once filled is taken out, the same work as in the case of constructing the purification wall 105 and the waste of the high quality soil occur, and the amount of the high quality soil necessary for the construction labor and replacement associated therewith is generated. However, it was a considerable amount, and the construction period was lengthened.

Japanese Patent Laid-Open No. 2003-10832 Japanese Patent Laid-Open No. 2003-126837 Soil Environment Center, Inc. Issued in November 2004 Soil Environment Center Technical News No. 9 P49 3.1 Outline of Purification Work Figure 3 (b) Example of arrangement of purification piles

  The present invention has been made in light of the existence of such background technology and the problems of the background technology, and minimizes the amount of overburden and overlap of the casing for excavation as much as possible to reduce the actual amount of excavated soil. By approaching the required amount of excavated soil, work efficiency is improved by eliminating waste of work, and the amount of materials used for filling is reduced to reduce material costs and construction costs and shorten the construction period. It is an object of the present invention to provide an excavating casing, a rectangular hole excavation method, a purification wall construction method for contaminated ground, and a purification / replacement method for contaminated ground.

  In order to solve the above-mentioned problem, the excavation casing according to the first aspect of the present invention is an excavation used when excavating the ground into a rectangular shape to form a rectangular hole with a predetermined opening and a predetermined depth in the ground. The excavation casing is constituted by a square steel pipe.

  According to the first aspect of the present invention, by using a square steel pipe as a casing for excavation, the amount of surplus when excavating a rectangular hole is reduced, thereby eliminating work waste and improving work efficiency. be able to. Moreover, since waste of soil, material, etc. filled in the excavated rectangular hole can be reduced, it is possible to reduce material cost and construction cost and shorten the construction period.

  The excavation casing according to the second aspect of the present invention is an excavation casing used when excavating the ground into a rectangular shape to form a rectangular hole having a predetermined opening and a predetermined depth in the ground, The casing for excavation is constituted by combining a square steel pipe and a U-shaped steel material having a U-shaped cross section.

  According to the second aspect of the present invention, by using a square steel pipe and a U-shaped steel material in combination as a casing for excavation, the amount of overlap between the square steel pipe and the U-shaped steel material, or between the U-shaped steel materials. Is almost none. Accordingly, the amount of extra excavation when excavating a rectangular hole is extremely small, so that waste of work can be eliminated and further improvement in work efficiency can be achieved. In addition, since the waste of soil, material, etc. filled in the excavated rectangular hole can be extremely reduced, it is possible to further reduce the material cost and the construction cost and further shorten the construction period.

The excavation casing according to a third aspect of the present invention is the casing according to the second aspect of the present invention, wherein the square steel pipe and the U-shaped steel material include a square steel pipe and a U-shaped steel material or U-shaped steel materials. A joint member for connection is provided.
According to the third aspect of the present invention, the U-shape is formed by the engagement guide action by the joint member even if the placement position and the placement angle at the time of placing the U-shaped steel material are not so skilled in work. The steel material can be placed accurately and easily.

  The excavation casing according to a fourth aspect of the present invention is the excavation casing according to the third aspect of the present invention, wherein the joint member includes two corner portions in the connection direction of the square steel pipe and two separation portions in the connection direction of the U-shaped steel material. The end portion and the two corner portions are formed over substantially the entire length of the square steel pipe and the U-shaped steel material.

  According to the fourth aspect of the present invention, after placing the U-shaped steel material, the wall surface in the connecting direction of the previously placed square steel pipe or other U-shaped steel material is the U-shaped steel material. Since a rectangular earth retaining section in which the open surface between the two separated ends is completely closed is formed, the same earth retaining action as when a square steel pipe is used is exhibited.

  According to a fifth aspect of the present invention, in the excavating casing according to any one of the first to fourth aspects of the present invention, the square steel pipe is a steel pipe having a square section with a side length of about 1 to 1.5 m. The U-shaped steel material is combined with a square steel pipe or other U-shaped steel material to form a rectangular earth retaining section having a square cross section with a side length of about 1 to 1.5 m. It is a shape steel material dimensioned in this way.

  According to the fifth aspect of the present invention, it becomes possible to cope with excavation from a small rectangular hole to a long rectangular hole in a groove shape or a planar rectangular hole with a large diameter, and for excavation in various construction fields or construction points. The casing can be used. In addition, since the earth retaining section formed between the U-shaped steel and the square steel pipe or other U-shaped steel is set to be the same as the size and shape of the square steel pipe, the square steel pipes are combined. As in the case, the square steel pipe and the U-shaped steel material can be efficiently arranged.

The rectangular hole excavation method according to the sixth aspect of the present invention excavates a rectangular hole by excavating the ground into a rectangular shape using a casing for excavation and forming a rectangular hole having a predetermined opening and a predetermined depth in the ground. An excavation casing made of square steel pipe is used in the excavation method for the rectangular hole, the excavation casing is placed on the ground forming the rectangular hole, and the ground in the excavation casing is auged. It is characterized in that it is excavated in a circular shape by an excavating means such as an auger machine equipped with a screw, and the earth and sand remaining in the corners are removed by using an earth discharging means such as a clam bucket.
According to the sixth aspect of the present invention, since the ground in the square steel pipe can be efficiently excavated in a rectangular shape, the amount of extra excavation is reduced, the waste of work is eliminated, and the construction labor is reduced and the construction period is shortened. Can do.

  According to a seventh aspect of the present invention, there is provided a rectangular hole excavation method according to the sixth aspect of the present invention, wherein the rectangular steel pipe is used to form a groove-shaped rectangular hole having a long width or depth, or an opening. When a rectangular hole with a large area is to be formed, the rectangular hole is elongated or enlarged by placing the square steel pipes in an overlapping manner while linearly shifting them in the width direction or the depth direction. It is characterized by that.

  According to the seventh aspect of the present invention, only rectangular steel pipes of the same size are used, from small rectangular holes of the same size as square steel pipes to grooved rectangular holes having a long width or depth dimension and large rectangular holes having a large opening area. It becomes possible to form using. Also, by using square steel pipes, the amount of overlap between square steel pipes can be made extremely small, so the amount of overburden can be reduced, work waste can be eliminated, work efficiency can be improved, and construction costs can be reduced. The construction period can be shortened.

  The rectangular hole excavation method according to the eighth aspect of the present invention excavates a rectangular hole by excavating the ground into a rectangular shape using a casing for excavation and forming a rectangular hole having a predetermined opening and a predetermined depth in the ground. In the method for excavating a rectangular hole, a casing for excavation combining a square steel pipe and a U-shaped steel material having a U-shaped cross section is used, and the square steel pipe is first formed on the ground forming the rectangular hole. And excavating the ground in the square steel pipe into a circular shape by an excavating means such as an auger machine equipped with an auger screw, and further removing earth and sand remaining in the corner corner using an excavating means such as a clam bucket. In the same manner, the ground in the retaining section partitioned by the square steel pipe and the U-shaped steel material is similarly placed along the square steel pipe. U-shaped excavated and earthed, and then U-shaped steel material is placed in order. It is characterized in that so as to form a rectangular hole having a predetermined width to depth by going to pouring so as to extend along the steel.

  According to the eighth aspect of the present invention, the ground in the square steel pipe and the ground in the retaining section can be excavated efficiently in a rectangular shape, so that the amount of extra excavation can be reduced and the waste of work can be reduced. The construction period can be shortened. In addition, by connecting and using the U-shaped steel material, a groove-shaped rectangular hole having a long width or depth can be excavated extremely efficiently.

  A rectangular hole excavation method according to a ninth aspect of the present invention uses the casing for excavation in the eighth aspect of the present invention, which is a combination of the square steel pipe and a U-shaped steel material having a U-shaped cross section. When forming a planar rectangular hole having a large opening area, the excavation casing is placed while sequentially shifting in a state of being overlapped in a direction orthogonal to the connection direction of the excavation casing. The rectangular hole is expanded in a planar shape.

  According to the ninth aspect of the present invention, a planar rectangular hole having a large opening area can be efficiently formed by using only a square steel pipe and a U-shaped steel material. Also, by using square steel pipes and U-shaped steel materials, the amount of overlap between square steel pipes and U-shaped steel materials or between U-shaped steel materials can be made extremely small, reducing the amount of overburden, By eliminating waste, it is possible to reduce construction labor, reduce construction costs, and significantly shorten the construction period.

According to a tenth aspect of the present invention, in the excavation method for a rectangular hole according to any one of the sixth to ninth aspects of the present invention, when the excavation casing is placed, the outer surface and the inner surface of the excavation casing are formed. A friction reducing material is applied to or pasted on both or one of them.
According to the tenth aspect of the present invention, it is possible to reduce the frictional resistance at the time of placing and extracting the excavating casing, so that the square steel pipe or the U-shaped steel material can be smoothly placed and pulled out. It is possible to improve work efficiency and prevent damage to the casing for excavation.

  The contaminated ground purification wall construction method according to the eleventh aspect of the present invention is to prevent the pollutant discharged from the pollutant from penetrating into the ground where the pollutant exists and flowing out to the surrounding ground through groundwater or the like. A purification wall construction method for the contaminated ground that constructs a purification wall between the soil and the surrounding ground, wherein the purification wall construction method for the contaminated ground uses a casing for excavation composed of square steel pipes, After forming a rectangular hole by the rectangular hole excavation method according to the sixth aspect, after filling the rectangular hole with a purification material and pulling out the square steel pipe, sequentially by the rectangular hole excavation method according to the seventh aspect Constructing a purification wall with a predetermined width or depth by repeatedly placing and purging the above-mentioned purification material and pulling out the square steel pipe together with the excavation and earthing of the square steel pipe You It is characterized in that so.

  According to the eleventh aspect of the present invention, the amount of surplus when excavating a rectangular hole is reduced by using a square steel pipe, so work efficiency can be improved and work efficiency can be improved. Moreover, since the waste of the purification material filled in the excavated rectangular hole can be reduced, the material cost can be reduced. Thereby, the construction labor required for construction of the purification wall can be reduced, and the construction period can be shortened.

  According to the twelfth aspect of the present invention, the contaminated ground purification wall construction method is used to prevent the pollutant discharged from the pollution source from penetrating into the ground where the pollution source exists and flowing out to the surrounding ground through groundwater or the like. A purification wall construction method for the contaminated ground that constructs a purification wall between the ground and the surrounding ground, the purification wall construction method for the contaminated ground includes a square steel pipe and a U-shaped steel material having a U-shaped cross section. In combination with the rectangular hole excavation method according to the eighth aspect, the rectangular steel pipe or the U-shaped steel material is sequentially placed and the rectangular steel pipe or the U-shaped steel material is The excavation and earth excavation of the ground in the retaining section formed between the U-shaped steel materials is performed, and the rectangular hole excavated together with this excavation is filled with the purification material and the square steel pipe or the U-shaped steel material is pulled out. Predetermined width by repeatedly executing It is characterized in that so as to build the clean walls of the law or depth.

  According to the twelfth aspect of the present invention, by using a combination of a square steel pipe and a U-shaped steel material, there is almost no overlap between the square steel pipe and the U-shaped steel material, or between the U-shaped steel materials. Become. Accordingly, the amount of extra excavation when excavating a rectangular hole is extremely small, so that waste of work can be eliminated and further improvement in work efficiency can be achieved. Moreover, since the waste of the purification material filled in the excavated rectangular hole can be extremely reduced, the material cost can be further reduced. Thereby, the construction labor required for construction of the purification wall can be further reduced, and the construction period can be further shortened.

  According to the thirteenth aspect of the present invention, the contaminated ground purification / replacement method excavates and removes contaminated soil from the contaminated ground, which is contaminated by the pollutants and spreads in a plane, and removes the high quality soil in the rectangular holes generated by the excavation. This is a contaminated ground purification / replacement method in which the contaminated ground is replaced with high-quality ground by refilling the soil, and the contaminated ground purification / replacement method uses a drilling casing composed of square steel pipes. After excavating the ground in the square steel pipe by the excavation method of the rectangular hole according to the sixth aspect, filling the formed rectangular hole with good quality soil, and pulling out the square steel pipe, to the seventh aspect The rectangular hole excavation method is used to place a square steel pipe, and the ground in the square steel pipe is excavated and soiled. Form a wall-shaped high-quality ground with the depth of the chair, and repeat the above procedure to place the square steel pipes in the direction perpendicular to the connecting direction of the square steel pipes, and expand the good-quality ground into a planar shape. In this way, all contaminated ground is replaced with high quality ground and purified.

  According to the thirteenth aspect of the present invention, it is possible to efficiently excavate a planar rectangular hole having a large opening area using only a square steel pipe of the same size with a small amount of surplus and overlap. Accordingly, it becomes easy to replace the contaminated ground with high-quality ground, and the construction labor required for the replacement can be reduced, and the construction period can be further shortened.

  According to the fourteenth aspect of the present invention, the contaminated ground purification / replacement method excavates and removes the contaminated soil from the contaminated ground that has been permeated by the pollutant and spreads in a planar shape, and the high quality soil is removed in the rectangular hole generated by the excavation. This is a contaminated ground purification / replacement method in which the contaminated ground is replaced with high-quality ground by refilling it, and the contaminated ground purification / replacement method includes a square steel pipe and a U-shaped cross section. A casing for excavation combined with a U-shaped steel material is used, and the rectangular hole excavation method according to the eighth aspect sequentially places square steel pipes or U-shaped steel materials, and within the square steel pipe or U-shaped steel materials. Excavation and soil removal in the earth retaining section formed between or between the U-shaped steel materials, and in addition to this, filling the rectangular holes created by excavation with high quality soil and square steel pipes or U-shaped steel materials Repeatedly withdraw By forming a good quality ground with a predetermined width dimension or depth dimension, and then expanding the rectangular hole into a plane by the rectangular hole excavation method according to the ninth aspect, It is characterized in that all the contaminated ground is replaced with high quality ground by repeatedly performing the extraction of the U-shaped steel material and cleaned.

  According to the fourteenth aspect of the present invention, it is possible to efficiently excavate a planar rectangular hole having a large opening area with an extremely small overlap amount using only a square steel pipe and a U-shaped steel material. Along with this, it becomes easier to replace the contaminated ground with high-quality ground, the construction labor required for the replacement can be greatly reduced, and the construction period can be further shortened.

  According to the present invention, it is possible to reduce the amount of overlap and the overlap amount of the casing for excavation. Along with this, excavation efficiency is improved, and the construction period can be shortened and the construction cost can be reduced. In addition, since there is no waste of purification material and high-quality soil that fills the excavated rectangular holes, material costs can be reduced, and the work that has been performed redundantly is eliminated, so the construction labor can be greatly reduced. it can. Then, by using the excavation casing having such effects, the excavation of the rectangular hole, the purification wall construction on the contaminated ground, and the purification / replacement of the contaminated ground can be carried out smoothly and efficiently.

  Hereinafter, the excavation casing according to the present invention, the excavation method of the rectangular hole using the excavation casing, the purification wall construction method to the contaminated ground using the excavation method of the rectangular hole and the purification / replacement method of the contaminated ground, The following Example 1 and Example 2 will be described as examples. In addition, the reference hole H used in this specification is the rectangular hole 2 of the minimum unit formed by using the single casing 1 for excavation. In addition to the hole H, a hole formed by connecting a plurality of reference holes H in series in the width direction or the depth direction, or by connecting the reference holes H also in a direction orthogonal to the connection direction. Large planar holes are also included. Further, the side on which the first excavation casing 1 is placed is referred to as a start side, and the side on which the last excavation casing 1 is placed is referred to as a termination side.

  Moreover, in the following Example 1 and Example 2, two types of excavation casings 1 having different configurations are taken up, and each excavation casing 1 is individually described in the section of (1) Excavation casing configuration. 2) The case of (i) excavating a groove-shaped rectangular hole and (ii) excavating a planar rectangular hole will be described using the respective excavating casings 1 in the section of the excavation method for rectangular holes. Then, (3) the soil purification and replacement method, each of the excavating casings 1 is used to excavate a groove-like rectangular hole 2 between the contaminated ground GA and the surrounding ground GB (i) the purification wall. And (ii) replacing the soil by excavating the planar rectangular hole 2 to replace the contaminated soil MA with the high-quality soil MB.

  FIG. 1 is a perspective view showing a case where a purification wall is formed between a contaminated ground and a surrounding ground by excavating a groove-shaped rectangular hole using a square steel pipe. FIG. 2 is a perspective view showing a case in which a square rectangular tube is used to excavate a planar rectangular hole to replace contaminated soil with good quality soil. FIG. 3 is a perspective view showing a square steel pipe (a) and a U-shaped steel material (b) of the excavation casing according to the second embodiment, and FIG. 4 is various views of joint members provided in the excavation casing according to the second embodiment. It is a top view which shows a structure. FIG. 5 is a plan view showing a case where a rectangular rectangular hole is excavated using a square steel pipe, and FIG. 6 is a plan view showing a case where a planar rectangular hole is excavated using a square steel pipe. FIG. 7 is a plan view showing a part of a case where a groove-shaped rectangular hole is excavated using the excavating casing according to the second embodiment, and FIG. It is a top view which shows a part in the case of excavating a rectangular hole. FIG. 9 is a plan view showing the whole of a case where a planar rectangular hole is excavated using the excavation casing according to the second embodiment.

  FIG. 10 is a diagram showing a procedure for constructing a purification wall using a square steel pipe as a casing for excavation, and is a perspective view showing a state where a placing guide is installed. FIG. 11 is a side sectional view showing a procedure for constructing a purification wall using a square steel pipe and showing a state where an auger screw is set in an auger machine. FIG. 12 is a diagram showing a procedure for constructing a purification wall using a square steel pipe, a perspective view showing a state where an auger machine is set in accordance with a placement guide, and FIG. 13 is a procedure for constructing a purification wall using a square steel pipe They are side sectional drawing (a) and AA sectional drawing (b) which show the state which excavates the ground with an auger screw while driving a square steel pipe. FIG. 14 is a diagram showing a procedure for constructing a purification wall using a square steel pipe. Side cross-sectional views (a) and B showing a state in which earth and sand remaining in the corner of the square steel pipe are removed using a clam bucket. -B cross-sectional view (b), CC cross-sectional view (c), and FIG. 15 are diagrams showing a procedure for constructing a purifying wall using a square steel pipe. The purifying wall is completed by filling the formed rectangular hole with the purifying material. They are side sectional drawing (a) and DD sectional drawing (b) which show the state made to do. FIG. 16 is a plan view showing a conventional method for excavating a groove-shaped rectangular hole using a circular steel pipe, and FIG. 17 is a plan view showing a conventional method for excavating a planar rectangular hole using a circular steel pipe.

[Example 1]
(1) Configuration of casing for excavation (see FIGS. 1, 2, 5, and 6)
The excavation casing 1 of the present invention is used when excavating the ground GL into a rectangular shape to form a rectangular hole 2 having a predetermined opening and a predetermined depth in the ground G. In the first embodiment, the excavation casing 1 is composed of only the square steel pipe 3. The square steel pipe 3 is a rectangular pipe-shaped rectangular casing having a square cross section with a side length of about 1 to 1.5 m and a casting length of about 10 m to 20 m. It can be used as an example.

(2) Excavation method for rectangular holes (see FIGS. 5, 6, and 10-14)
(I) When excavating a groove-like rectangular hole (see FIGS. 5 and 10 to 14)
The rectangular hole excavation method of the present invention is carried out when the ground GL is excavated in a rectangular shape using the excavating casing 1 to form the rectangular hole 2 having a predetermined opening and a predetermined depth in the ground G. In this embodiment, the excavating casing 1 constituted by the square steel pipe 3 is used, the square steel pipe 3 is driven on the ground GL forming the rectangular hole 2, and the ground G in the square steel pipe 3 is attached to the auger screw 4. The auger machine 5 or the like provided is excavated into a circular shape, and the earth and sand T remaining in the corner corner 6 is removed using a clam bucket 7 or the like.

  Specifically, as shown in FIG. 10, the placement guide 8 is installed on the ground GL excavating the rectangular hole 2. The placement guide 8 is a rectangular frame-like member that is long in the connection direction J of the square steel pipe 3, and the left and right side portions 9 extending in the connection direction J are made of long H-shaped steel. The two end sides 10 that connect both ends of the portion 9 are made of a rectangular flat steel that is somewhat thick. And the inner wall surface of these two side parts 9 and end side parts 10 provided by two is the guide surface 11 when placing the square steel pipe 3, and the corner is formed at the center of the two side parts 9. A casting center line L serving as a reference when the steel pipe 3 is cast is positioned.

  Next, as shown in FIG. 11, the auger screw 4 is set in the auger machine 5, and the square steel pipe 3 is attached to the outside of the auger screw 4 so as to wrap the auger screw 4. Then, as shown in FIG. 12, the auger machine 5 is set so that the center of the square steel pipe 3 and the auger screw 4 is positioned on the placement center line L in accordance with the placement guide 8, and the perpendicular of the square steel pipe 3. Check the degree. Next, as shown in FIG. 13, the auger machine 5 is activated to rotate the auger screw 4 in the excavating direction to excavate the ground G, and the square steel pipe 3 is gradually little by the own weight of the auger screw 4 and the square steel pipe 3. Is pushed down into the ground G, and the square steel pipe 3 is driven into the ground G. Then, after placing the square steel pipe 3, the auger screw 4 is slowly pulled up, and the earth and sand T at the center of the excavated square steel pipe 3 is carried out to the ground.

  Next, as shown in FIG. 14, the clam bucket 7 is inserted into the square steel pipe 3 instead of the auger screw 4, and the earth and sand T remaining in the corner corner 6 of the square steel pipe 3 is excavated and carried out to the ground. The clam bucket 7 is formed in a square shape so as to match the shape and size of the square steel pipe 3. Further, when the frictional resistance with the ground G when placing the square steel pipe 3 is large, the friction reducing material 12 is applied or pasted on both the outer surface and the inner surface of the square steel pipe 3 or one of them. As the friction reducing material 12, a resin, a lubricating oil, grease, or the like applied to the square steel pipe 3 or a resin film attached to the square steel pipe 3 can be used. Further, these friction reducing materials 12 exhibit the effect of reducing the frictional resistance even when the cast square steel pipe 3 is pulled out.

  In the same manner, as shown in FIG. 5, the rectangular steel pipes 3 are placed in a state of being overlapped in a straight line in the connecting direction J, which is the width direction or the depth direction, while being somewhat overlapped. The holes 2 are gradually extended to form a groove-shaped rectangular hole 2 having a predetermined length. In FIG. 5, a square steel pipe 3 having a side length of 1 m is used, the overlap amount O of the square steel pipe 3 is 8 cm, the casting pitch P of the square steel pipe 3 is 92 cm, the width 1 m, the length 160 m, the depth A case where a groove-shaped rectangular hole 2 having a length of 10 m is formed is shown.

The required excavated soil volume V in this case is 1 m × 160 m × 10 m = 1600 m ³ , the actual excavated soil volume W is 0.999 m × 174 m × 10 m = 1737 m ³ , and the surplus moat U is W−V = 138m ^3, drilling loss rate S is approximately 8.6% in U ÷ V. Therefore, it can be seen that the excavation efficiency is remarkably improved as compared with the excavation loss rate S of about 79.6% in the case of the conventional method shown in FIG. 16 using the circular steel pipe described above.

(Ii) When excavating a planar rectangular hole (see Fig. 6)
First, a reference hole H is formed in the same procedure as in the case of excavating the groove-shaped rectangular hole 2, and the square steel pipes 3 are sequentially linearly driven in the connecting direction J at a predetermined driving pitch P. Thus, the rectangular hole 2 is elongated to form a groove-shaped rectangular hole 2 having a width or depth dimension of a predetermined length. Then, the square steel pipe 3 is somewhat overlapped in the direction orthogonal to the connection direction J to form a groove-like rectangular hole 2 similar to the above, and thereafter the above operation is repeated until the predetermined opening area is reached. Thus, the rectangular hole 2 is enlarged to obtain a planar rectangular hole 2 having a predetermined size.

  In FIG. 6, a square steel pipe 3 having a side length of 1 m is used, the overlap amount O of the square steel pipe 3 is 8 cm, the casting pitch P of the square steel pipe 3 is 92 cm, the width is 10 m, the depth is 10 m, and the depth. The case where the 10-mm planar rectangular hole 2 is formed is shown. And the excavation loss rate S in this case is about 20.9%, compared with the excavation loss rate S in the case of the conventional method shown in FIG. 17 using the circular steel pipe described above being about 70.4%. It can be seen that the drilling efficiency has improved remarkably.

(3) Purification / replacement method for contaminated ground (See Figs. 1, 2, and 15)
(I) When a purification wall is formed (see FIGS. 1 and 15)
In the method for constructing a purification wall for contaminated ground according to the present invention, the pollutant Q discharged from the chemical factory 13 or the like as a pollution source penetrates into the ground G below the site of the chemical factory 13 or the like, and passes through the groundwater 14 or the like to the surrounding ground GB. This can be used when the purification wall 15 is constructed between the contaminated ground GA and the surrounding ground GB in order to prevent the outflow.

  In this embodiment, the square steel pipe 3 is used as a casing for excavation, the rectangular rectangular hole 2 is formed by the above-described rectangular hole excavation method, and the purification material 23 which becomes the material of the purification wall 15 in the rectangular hole 2. The purifying wall 15 is constructed by filling a known purifying material F made of sand and sand 24 or the like. Specifically, after using the square steel pipe 3 to form the reference hole H at the start position where the purification wall 15 is constructed by the procedure shown in FIGS. 10 to 14 and filling the reference hole H with the purification material F The square steel pipe 3 is pulled out. Then, in accordance with the procedure of the excavation method of the rectangular hole described above, the square steel pipe 3 is sequentially placed, the ground in the square steel pipe 3 is excavated and soiled, and the purification material F shown in FIG. The purification wall 15 having a predetermined width dimension or depth dimension is constructed by repeatedly performing the extraction 3.

  As an example of the purification material 23, iron powder can be used, and the purification material F made of the iron powder and sand 24 is filled in the rectangular hole 2 as a raw material for the purification wall 15. Further, the purifying material F is filled up to the level of the ground GL, and after the filling of the purifying material F, the square steel pipe 3 is drawn upward. Then, as shown in FIG. 1, the contaminated ground GA and the surrounding ground GB are partitioned by the constructed purification wall 15, so that the pollutant Q in the contaminated ground GA is carried by the groundwater 14 etc. and flows out to the surrounding ground GB. Things are prevented.

(Ii) When replacing soil (see Fig. 2)
The contaminated ground purification / replacement method according to the present invention excavates and removes the contaminated soil MA in the contaminated ground GA, which is contaminated with the pollutant Q and spreads in a plane, and removes the high quality soil MB in the rectangular hole 2 generated by the excavation. It is also used in the case where the contaminated ground GA is replaced with a high-quality ground GC by being backfilled.

  In this embodiment, a square steel pipe 3 is used. After the rectangular hole 2 is formed by the above-described rectangular hole excavation method, the contaminated soil MA is taken out, and the formed rectangular hole 2 is filled with high-quality soil MB. Then, the contaminated ground GA is purified and replaced by pulling out the square steel pipe 3.

  Specifically, the rectangular steel pipe 3 is sequentially placed and the ground G in the square steel pipe 3 is excavated by the above-described rectangular hole excavation method, and the filling of the high quality soil MB and the extraction of the square steel pipe 3 are repeated in conjunction with this. By executing this, a wall-shaped high-quality ground GC having a predetermined width dimension or depth dimension is formed. Then, the above procedure is repeated to place all the soil by placing the square steel pipe 3 in a state of being somewhat overlapped in a direction perpendicular to the connection direction J of the square steel pipe 3 and expanding the good quality ground GC. Try to replace it. In this construction method, as shown in FIG. 2, the contaminated ground GA is completely replaced with the high-quality ground GC, and therefore, the expansion of the contaminated ground GA to the surrounding ground GB is fundamentally prevented.

[Example 2]
(1) Configuration of casing for excavation (see FIGS. 3, 7, 8, and 9)
In Example 2, the excavation casing 1 is configured by combining a square steel pipe 3 and a U-shaped steel material 16 having a U-shaped cross section. As the square steel pipe 3, as in the square steel pipe 3 according to Example 1 described above, the length of one side has a square cross section of about 1 to 1.5 m, and the placement length to be placed in the ground G is as follows. As an example, a rectangular casing having a square pipe shape of about 10 m to 20 m can be used. Further, at two corner portions 17 in the connecting direction J of the square steel pipe 3, joint members 18 are formed over almost the entire length of the square steel pipe 3, as shown in FIG.

  On the other hand, the U-shaped steel material 16 is a rectangular earth retaining section having a square cross section with a side length of about 1 to 1.5 m when combined with the square steel pipe 3 or the other U-shaped steel material 16. A steel material having a U-shaped cross-section dimensioned so that 19 is formed can be applied. Further, the casting length to be cast in the ground G of the U-shaped steel material 16 is set to about 10 m to 20 m as an example, like the square steel pipe 3. Further, the two separated end portions 20 and the two corner portions 21 in the connection direction J of the U-shaped steel material 16 are provided with a joint member 18 provided in the square steel pipe 3 as shown in FIG. The joint member 22 to be connected is formed over substantially the entire length of the U-shaped steel material 16.

  As shown in FIG. 4A, the joint members 18 and 22 are configured such that one of the joint members 18 or 22 has a C-shaped cross section, and the other joint member 22 or 18 has a O-shaped cross section. As shown in FIG. 4B, the cross-sectional shape of one joint member 18 or 22 is C-shaped, and the cross-sectional shape of the other joint member 22 or 18 is T-shaped, or as shown in FIG. As described above, various configurations such as a configuration in which both the joint members 18 and 22 are in a U shape or a J shape can be employed.

(2) Excavation method for rectangular holes (see Figs. 7, 8, and 9)
(I) When excavating a groove-shaped rectangular hole (see Fig. 7)
In this embodiment, the excavation casing 1 configured by combining the above-described square steel pipe 3 and the U-shaped steel material 16 is used. And in the excavation method of the rectangular hole of this invention, the square steel pipe 3 is first driven in the position of the start end side of the ground GL which forms the rectangular hole 2, and the center of the ground G in the square steel pipe 3 is earthed. Is excavated into a circle with an auger screw 4 or the like. And the earth and sand T remaining in the corner | angular corner part 6 in the square steel pipe 3 is removed using the clam bucket 7 grade | etc.,. Next, the cut-off end portion 20 of the U-shaped steel material 16 is directed so as to follow the square steel pipe 3 previously placed, and the U-shaped steel material 16 is driven by engaging the joint members 18 and 22. To do.

  Next, the ground G in the earth retaining section 19 partitioned by the square steel pipe 3 and the U-shaped steel material 16 previously placed is similarly excavated, and the U-shaped steel material 16 is sequentially placed first. The joint members 18 and 22 are engaged so as to be along the U-shaped steel material 16 and the U-shaped steel material 16 is driven one after another to form a groove-shaped rectangle having a predetermined width dimension or depth dimension. Hole 2 is formed. Then, according to such a rectangular hole excavation method, the surplus amount U and the overlap amount O do not theoretically occur, so the excavation loss rate S becomes 0%, and extremely high excavation efficiency can be obtained.

(Ii) When excavating a planar rectangular hole (see FIGS. 8 and 9)
In the same procedure as when the groove-shaped rectangular hole 2 is excavated, the square steel pipe 3 is first used to form the reference hole H at the starting end position, and the joint members 18 and 22 are engaged so that the square steel pipe 3 and The U-shaped steel material 16 is linearly driven in the connecting direction J at a pitch P which is the same as the length of one side of the earth retaining section 19. Accordingly, the rectangular hole 2 is elongated to form a groove-shaped rectangular hole 2 having a width or depth dimension of a predetermined length. Then, the rectangular steel tube 3 and the U-shaped steel material 16 are somewhat overlapped in the direction perpendicular to the connection direction J to form the groove-shaped rectangular hole 2 similar to the above, and thereafter the predetermined opening area is similarly set. The above operation is repeated until the rectangular hole 2 is enlarged to obtain a planar rectangular hole 2 having a predetermined size.

  In FIG. 9, a rectangular rectangular hole is formed by using a U-shaped steel material 16 having a side length of 1 m which is 1 m on the side of the retaining section 19 formed when combined with a square steel pipe 3 having a side length of 1 m. The overlap amount O in the expansion direction of 2 is 8 cm, the pitch P of the square steel pipe 3 and the U-shaped steel material 16 is 92 cm, and a planar rectangular hole 2 having a width of 10 m, a depth of 10 m, and a depth of 10 m is formed. Shows the case. In this case, the surplus amount U is generated at a part of the upper end and a part of the lower end in FIG. 9, and the excavation loss rate S is about 9.9%. 70.4%) is greatly exceeded, and a high excavation efficiency exceeding the excavation loss rate S (about 20.9%) in the case of Example 1 is obtained.

(3) Purification / replacement method for contaminated ground (See Figs. 1, 2, and 15)
(I) When a purification wall is formed (see FIGS. 1 and 15)
In the present embodiment, a casing 1 for excavation in which a square steel pipe 3 and a U-shaped steel material 16 are combined is used, and the inside of the square steel pipe 3 and the soil are sequentially formed by the rectangular hole excavation method for excavating the groove-shaped rectangular hole 2 described above. The ground G in the retaining section 19 is excavated. Then, the purifying material F is filled into the rectangular hole 2 excavated together with this, and the work of pulling out the square steel pipe 3 or the U-shaped steel material 16 is repeatedly performed, thereby purifying the purifying wall 15 in a predetermined width dimension or depth direction. To build. Then, as shown in FIG. 1, the contaminated ground GA and the surrounding ground GB are partitioned by the constructed purification wall 15, so that the pollutant Q in the contaminated ground GA is carried by the groundwater 14 etc. and flows out to the surrounding ground GB. Things are prevented.

(Ii) When replacing soil (see Fig. 2)
In the present embodiment, a casing 1 for excavation in which a square steel pipe 3 and a U-shaped steel material 16 are combined is used, and the inside of the square steel pipe 3 and the soil are sequentially formed by the rectangular hole excavation method for excavating the groove-shaped rectangular hole 2 described above. The ground G in the retaining section 19 is excavated. Along with this, a rectangular hole 2 produced by excavation is filled with high-quality soil MB, and the work of drawing out the square steel pipe 3 or the U-shaped steel material 16 is repeatedly performed, thereby forming a wall-like shape having a predetermined width dimension or depth dimension. A good quality ground GC is formed. After that, the rectangular hole 2 is expanded by the rectangular hole excavation method for excavating the planar rectangular hole 2 described above, and the high-quality soil MB is filled and the square steel pipe 3 or the U-shaped steel material 16 is pulled out repeatedly. Try to replace all soils. In this construction method, as shown in FIG. 2, the contaminated ground GA is completely replaced with the high-quality ground GC, and therefore, the expansion of the contaminated ground GA to the surrounding ground GB is fundamentally prevented.

[Other embodiments]
Excavation casing 1 according to the present invention, a rectangular hole excavation method using the excavation casing 1, a purification wall construction method for contaminated ground using the excavation method for the rectangular hole, and a purification / replacement method for contaminated ground, Although it is based on the configuration as described above, it is of course possible to change or omit a partial configuration within a range not departing from the gist of the present invention. For example, the rectangular hole 2 formed by the excavating casing 1 of the present invention does not include only a simple rectangular hole 2 having a cuboid shape in a strict sense, but the size of the square steel pipe 3 or the U-shaped steel material 16, etc. A complex structure having a combination of a plurality of reference holes H formed by connecting a reference hole H (which is also a rectangular hole 2) serving as a reference determined by the above in the connection direction J or in a direction orthogonal to the connection direction J. A rectangular hole 2 having a shape is also included. In addition, the excavation method of the rectangular hole of the present invention is not limited to the case of being used in the purification / replacement method of contaminated ground, but may be used for other purposes, such as ground improvement for replacing soft ground with strong high-quality ground. Of course it is possible.

  The invention of the present application is, for example, a construction site for a purification wall that prevents a pollutant discharged from a pollution source from penetrating into the ground where the pollution source exists and flowing out to the surrounding ground through groundwater, etc. It can be used in construction sites where the contaminated ground is purified and replaced by excavating the contaminated soil in the spread contaminated ground and replacing it with high quality soil, and can be used particularly when it is desired to excavate rectangular holes efficiently and without waste.

The perspective view which shows the case where a purification | cleaning wall is formed between a contaminated ground and a surrounding ground by excavating a groove-shaped rectangular hole using a square steel pipe. The perspective view which shows the case where a square-shaped rectangular hole is excavated using a square steel pipe, and contaminated soil is replaced with good quality soil. The perspective view which shows the square steel pipe (a) and U-shaped steel material (b) of the casing for excavation which concerns on Example 2. FIG. FIG. 10 is a plan view showing various configurations of a joint member provided in the excavation casing according to the second embodiment. The top view which shows the case where a square hole of a groove shape is excavated using a square steel pipe. The top view which shows the case where a planar rectangular hole is excavated using a square steel pipe. The top view which shows a part in the case of excavating a groove-shaped rectangular hole using the casing for excavation which concerns on Example 2. FIG. The top view which shows a part in the case of excavating a planar rectangular hole using the casing for excavation which concerns on Example 2. FIG. The top view which shows the whole in the case of excavating a planar rectangular hole using the casing for excavation which concerns on Example 2. FIG. The figure which shows the procedure of formation of the purification | cleaning wall which uses a square steel pipe, and is a perspective view which shows the state which installed the placement guide. The figure which shows the procedure of formation of the purification wall which uses a square steel pipe, and is a sectional side view which shows the state which set the auger screw to the auger machine. The figure which shows the procedure of formation of the purification wall using a square steel pipe, and is a perspective view which shows the state which set the auger machine according to the placement guide. It is the figure which shows the procedure of formation of the purification wall which uses the square steel pipe, side sectional view (a) which shows the state which excavates the ground with the auger screw while placing the square steel pipe, and the AA sectional view (b) . It is the figure which shows the procedure of formation of the purification wall which uses the square steel pipe, side sectional view (a) which shows the state where the earth and sand remaining in the corner corner inside the square steel pipe is removed using the clam bucket The figure (b) and CC sectional drawing (c). It is a figure which shows the procedure of formation of the purification | cleaning wall which uses a square steel pipe, The side sectional view (a) and DD sectional view (b) which show the state which filled the formed rectangular hole with the purification material and completed the purification wall . The top view which shows the conventional construction method which excavates a groove-shaped rectangular hole using a circular steel pipe. The top view which shows the conventional construction method which excavates a planar rectangular hole using a circular steel pipe.

Explanation of symbols

1 Excavation casing, 2 rectangular hole, 3 square steel pipe, 4 auger screw,
5 auger machines, 6 corners, 7 clam buckets, 8 placement guides, 9 sides,
10 edge, 11 guide surface, 12 friction reducing material, 13 chemical factory (contamination source),
14 groundwater, 15 purification wall, 16 U-shaped steel, 17 corner (square steel pipe),
18 joint member (of square steel pipe), 19 retaining section, 20 cut end,
21 corner part (of U-shaped steel), 22 joint member (of U-shaped steel),
23 purification material, 24 sand, H reference hole, V required excavated soil volume, W actual excavated soil volume,
U surplus amount, S excavation loss rate, GL ground, G ground, GA contaminated ground, GB peripheral ground GC high quality ground, MA contaminated soil, MB high quality soil, T sediment, J connection direction,
L placement center line, O overlap amount, P placement pitch, Q pollutant, F purification material

Claims (14)

A casing for excavation used when excavating the ground into a rectangular shape to form a rectangular hole with a predetermined opening and a predetermined depth in the ground,
The excavation casing is constituted by a square steel pipe. A casing for excavation used when excavating the ground into a rectangular shape to form a rectangular hole with a predetermined opening and a predetermined depth in the ground,
The casing for excavation is constituted by combining a square steel pipe and a U-shaped steel material having a U-shaped cross section.   The excavation according to claim 2, wherein the square steel pipe and the U-shaped steel material are provided with a joint member for connecting the square steel pipe and the U-shaped steel material or the U-shaped steel materials to each other. casing.   4. The joint member according to claim 3, wherein the joint member is formed of a square steel pipe and a U-shaped steel material at two corner portions in the connecting direction of the square steel pipe, two separated ends in the connecting direction of the U-shaped steel material, and two corner portions. A casing for excavation characterized by being formed over substantially the entire length.   The square steel pipe according to any one of claims 1 to 4, wherein the square steel pipe is a steel pipe having a square cross section with a side length of about 1 to 1.5 m, and the U-shaped steel material is a square steel pipe or other U-shaped steel material. Excavation casing characterized in that it is a shaped steel material dimensioned so that a rectangular earth retaining section having a square cross section with a side length of about 1 to 1.5 m is formed in combination with a shaped steel material . A rectangular hole excavation method for excavating the ground into a rectangular shape using a casing for excavation and forming a rectangular hole with a predetermined opening and a predetermined depth in the ground,
The rectangular hole excavation method uses a digging casing constituted by a square steel pipe, the digging casing is placed on the ground forming the rectangular hole, and the ground in the digging casing is provided with an auger screw A rectangular hole excavation method characterized in that it is excavated in a circular shape by an excavating means such as, and the earth and sand remaining in the corner is removed by using an excavating means such as a clam bucket.   The square steel pipe is overlapped when the square steel pipe is used to form a rectangular rectangular hole having a long width or depth, or a planar rectangular hole having a large opening area. The rectangular hole excavation method is characterized in that the rectangular hole is extended or enlarged by placing it while being shifted linearly and sequentially in the width direction or the depth direction. A rectangular hole excavation method for excavating the ground into a rectangular shape using a casing for excavation and forming a rectangular hole with a predetermined opening and a predetermined depth in the ground,
In the excavation method of the rectangular hole, a casing for excavation combining a square steel pipe and a U-shaped steel material having a U-shaped cross section is used, and the square steel pipe is first placed on the ground forming the rectangular hole, The ground in the square steel pipe is excavated in a circular shape by an excavating means such as an auger machine equipped with an auger screw, and the earth and sand remaining in the corner corner is removed using a soil discharging means such as a clam bucket. The U-shaped steel material is placed so as to extend along the cut-off end, and the ground in the retaining section partitioned by the square steel pipe and the U-shaped steel material is similarly excavated and discharged. In the following, a rectangular hole having a predetermined width dimension or depth dimension is formed by sequentially placing the U-shaped steel material along the U-shaped steel material previously placed. Characteristic rectangular hole excavation method.   In the case of forming a planar rectangular hole having a large opening area using a digging casing in which the square steel pipe and a U-shaped steel material having a U-shaped cross section are combined, Excavation of a rectangular hole characterized in that the rectangular hole is expanded in a planar shape by placing the casing in a state of being sequentially shifted while being overlapped in a direction orthogonal to the connection direction of the casing for excavation Construction method.   In any one of Claims 6-9, when placing the said casing for excavation, the friction reducing material was applied to or pasted on both the outer surface and the inner surface of the casing for excavation, or one of them. A rectangular hole excavation method characterized by this. Purifying wall to contaminated ground to prevent the pollutant discharged from the pollutant from penetrating into the ground where the pollutant exists and flowing out to the surrounding ground through groundwater etc. A construction method,
A casing for excavation made of square steel pipe is used in the purification wall construction method for the contaminated ground, and after forming a rectangular hole by the rectangular hole excavation method according to claim 6, the purification material is applied to the rectangular hole. After filling and pulling out the square steel pipe, the rectangular hole is excavated and the ground in the square steel pipe is sequentially excavated and soiled by the excavation method of the rectangular hole according to claim 7. A purification wall construction method for contaminated ground, characterized in that a purification wall having a predetermined width dimension or depth dimension is constructed by repeatedly executing filling and drawing of a square steel pipe. Purifying wall to contaminated ground to prevent the pollutant discharged from the pollutant from penetrating into the ground where the pollutant exists and flowing out to the surrounding ground through groundwater etc. A construction method,
9. A casing for excavation combining a square steel pipe and a U-shaped steel material having a U-shaped cross-section is used for the purification wall construction method for the contaminated ground. The steel pipe or U-shaped steel material is placed and the ground is excavated and discharged in the earth retaining section formed between the square steel pipe or the U-shaped steel material or between the U-shaped steel materials. It is characterized in that a purification wall having a predetermined width dimension or depth dimension is constructed by repeatedly performing filling of the purification material into the rectangular hole excavated and drawing out the square steel pipe or the U-shaped steel material. Purification wall construction method for contaminated ground. The contaminated soil infiltrated with contaminants is excavated and removed from the contaminated ground by excavation, and the soil is replaced with high-quality soil by refilling the rectangular holes created by excavation and backfilling. A purification and replacement method for contaminated ground,
The excavation casing constituted by a square steel pipe is used for the purification / replacement method of the contaminated ground, and the ground in the square steel pipe is excavated by the excavation method of the rectangular hole according to claim 6 to form a rectangular hole formed. After filling the good-quality soil and pulling out the square steel pipe, the square-hole drilling method according to claim 7 is sequentially performed, and the ground in the square steel pipe is excavated and discharged, and the high-quality soil is combined with this. A wall-shaped ground with a predetermined width or depth is formed by repeatedly performing the filling of the soil and the pulling out of the square steel pipe, and the above procedure is repeated thereafter to form a corner in a direction perpendicular to the connecting direction of the square steel pipe. Cleaned contaminated ground, characterized by replacing all contaminated ground with good quality ground by placing the steel pipes in an overlapping state and expanding the good quality ground in a planar shape. And replacement method. The contaminated soil infiltrated with contaminants is excavated and removed from the contaminated ground by excavation, and the soil is replaced with high-quality soil by refilling the rectangular holes created by excavation and backfilling. A purification and replacement method for contaminated ground,
9. The excavation casing in which a square steel pipe and a U-shaped steel material having a U-shaped cross section are combined is used for the purification / replacement method of the contaminated ground, and the square steel pipe is sequentially formed by a rectangular hole excavation method according to claim 8. Or the placement of U-shaped steel materials and excavation and earthing of the ground in square retaining pipes formed between square steel pipes or U-shaped steel materials or between U-shaped steel materials A wall-shaped high-quality ground having a predetermined width or depth is formed by repeatedly performing filling of a high-quality soil into a rectangular hole generated by excavation and drawing of a square steel pipe or a U-shaped steel material, and then forming a wall-shaped high-quality ground with a predetermined width dimension or depth dimension. By replacing the contaminated ground with good quality ground by repeatedly executing filling of good quality soil and drawing out square steel pipes or U-shaped steel materials while expanding the rectangular holes into a planar shape by the rectangular hole excavation method described in 1. , Purification and replacement method for Contaminated Land, characterized in that so as to reduction.

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