JP2005146756A - Earth retaining wall construction method and earth retaining wall formed thereby - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel earth retaining impervious wall construction method for constructing an earth retaining impervious wall exceeding limit length in a steel sheet pile pressing-in construction method by use of a previously digged hole together and taking restoration of a subterranean stream into account and to provide the earth retaining impervious wall formed by the method. <P>SOLUTION: In this earth retaining impervious wall construction method for constructing the earth retaining impervious wall composed of a impervious zone Za in a lower end part and a pile soil pressure impervious zone Zb in its upper part, a process for forming a soil mortar column in a lower end part of a digged hole by digging the ground and a process for back-filling sifted soil of digged soil at construction site into a digged hole on the soil mortar column are sequentially repeated to form the continuous impervious wall 1 in the impervious zone Za. Next, a steel sheet pile 3 is pressed into an upper part of the soil mortar column by passing through a back-filled part to form the continuous earth retaining impervious wall 4 in the pile soil pressure impervious zone Zb. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a soil retaining wall construction method for constructing a soil retaining wall used for a deadline when constructing an underground structure, and a soil retaining wall formed thereby.

  Conventionally, a steel sheet pile press-in method combined with a pre-drilled hole is known as an effective earth retaining method for forming a retaining wall such as a deadline when constructing an underground structure.

This method is basically an auger as needed from the ground into the ground, using a casing built so as not to rotate and an auger screw having a drilling blade exposed at the lower end and rotating in the casing. Drilling while injecting bentonite solution or cement milk using the screw shaft core, and after the drilling reaches a predetermined depth, the casing and the auger screw are pulled up, and then a steel sheet pile having a connecting ear in the drilling hole Is inserted in such a way that the connecting ears face the pile row direction, and the steel sheet pile is inserted and embedded repeatedly by inserting the guide member of the casing into the connecting ear of the steel sheet pile already embedded in the next excavation. Is.
JP-A-55-142835

  The above-mentioned steel sheet pile press-in method combined with preceding drilling has the excellent advantages that it can be constructed without noise and vibration, construction is quick and accurate, there is no construction discharge soil, and vertical accuracy is high. Have. However, in this method, the length of the steel sheet pile that can be press-fitted is about 20 m, and when construction is performed beyond the limit length, if an auxiliary means such as a jet is used together, contamination occurs and the effect of non-polluting is lost. It will end up. In addition, there is a problem that it is difficult to press the steel sheet pile in a place where cobblestones and gravel are mixed.

  Therefore, as a construction method for constructing a water-impervious wall exceeding the press-fit limit length of a steel sheet pile, there is a construction method involving excavation such as an SMW wall construction method or an RC continuous wall construction method. However, the steel sheet pile wall that only press-fits the steel sheet pile requires less cost and labor for its construction and removal, and the construction period is shorter, but the SMW wall and RC continuous wall are less expensive and labor to build than the steel sheet pile wall. In addition to the long construction period, there is a problem that the removal requires a lot of cost and construction period. In addition, SMW walls built by mixing hardeners with local earth and sand can suppress construction waste as much as possible, but RC continuous walls have problems such as construction waste coming out.

  On the other hand, when constructing a long earth retaining wall, there is a risk of adversely affecting the groundwater environment, so it is necessary to immediately remove the earth retaining wall and return to the current state after constructing the underground structure. Is done. In addition, it is required not to produce construction earth and sand that will become industrial waste.

  The present invention has been made in view of such circumstances, and it is possible to construct a retaining wall that exceeds the limit length in the steel sheet pile press-in method combined with the prior drilling, and also considers the restoration of groundwater flow. The purpose is to provide a new earth retaining wall construction method and to provide the earth retaining wall formed by it.

  The earth retaining wall construction method according to claim 1 is a soil retaining wall construction method for constructing a dirt retaining wall comprising a water shielding zone at the lower end and an anti-earth pressure shielding zone at the upper part. Then, the process of excavating the ground to form a soil mortar column at the lower end of the excavation hole and the step of refilling the soil excavated soil in the excavation hole on the soil mortar column are sequentially repeated. Forming a continuous impermeable wall in the anti-earth pressure impermeable zone by forming a continuous impermeable wall in the water zone and then inserting a steel sheet pile into the top of the soil mortar column through the backfill. It is a feature.

  The construction method for constructing a retaining wall for impermeable walls according to claim 2 is the construction method for retaining wall for retaining earth walls according to claim 1, wherein after the continuous retaining wall is formed in the anti-earth pressure impermeable zone, at least shielding is performed. A water stop layer is formed by injecting a chemical solution to the back surface of the joint between the water zone and the anti-earth pressure impermeable zone.

  The construction method of construction of a retaining wall for impermeable walls according to claim 3 is the construction method of retaining wall for impermeable walls according to claims 1 to 2, wherein the soil mortar column is applied to the excavated soil at the lower end of the excavation hole. It is characterized by being formed by filling a soil mortar mixed with a curing agent.

  The construction method for construction of a retaining wall for impermeable walls according to claim 4 is the construction method for retaining wall for impervious walls according to claims 1 to 2, while injecting a cement mortar into the soil mortar column and the ground. It is characterized by being formed by stirring and mixing.

  The earth retaining wall which is the invention according to claim 5 is a soil retaining wall comprising a water shielding zone at the lower end and an anti-earth pressure water shielding zone at the upper part thereof, and the water shielding zone is a plurality of continuous water shielding zones. The anti-earth pressure impermeable zone penetrates the ground excavated soil that has been backfilled on the continuous impermeable wall and the backfill section. It is characterized by comprising a continuous earth retaining impermeable wall composed of a steel sheet pile pressed into the upper portion of the continuous impermeable wall.

  The earth retaining impermeable wall according to claim 6 is the earth retaining impermeable wall according to claim 5, wherein the impermeable zone is formed by injecting a chemical solution into the continuous impermeable wall and the back surface of the continuous impermeable wall. It is characterized by comprising a water-stopping layer formed.

  The earth retaining impermeable wall according to claim 7 is the earth retaining impermeable wall according to claims 5 to 6, wherein the soil mortar column is made of soil mortar mixed with hardener in the excavated soil. It is characterized by.

  An earth retaining impermeable wall according to an eighth aspect of the present invention is the earth retaining impermeable wall according to any one of the fifth to sixth aspects, wherein the soil mortar column is a soil obtained by injecting a cement-based hardener into the ground and stirring and mixing. It consists of mortar.

  Since the earth retaining wall construction method according to claim 1 is configured as described above, even if the limit length is exceeded by the steel sheet pile press-in method with a pre-drilled hole, the earth retaining wall is sufficient for water stoppage. A water wall can be constructed. Then, by forming the continuous earth retaining impermeable wall in the anti-earth pressure impermeable zone by press-fitting the steel sheet pile, the cost and labor required for the construction and removal of the steel sheet pile wall are light and the construction period can be shortened. In addition, since the soil excavated on the soil mortar column is backfilled with the soil excavated from the site, even if it is a place where cobblestone or gravel is mixed, Therefore, it is easy to press-fit steel sheet piles, and the discharge of construction residual soil from the construction site can be suppressed as much as possible.

  In addition to the above-mentioned effect, the earth retaining impermeable wall construction method according to claim 2 injects a chemical solution at least on the back surface of the joint portion between the impermeable zone and the anti-earth pressure impermeable zone to form a water blocking layer. Thus, even if a steel sheet pile is press-fitted into the soil mortar, even if a crack occurs in the soil mortar wall, the water blocking layer can suppress the deterioration of the water shielding function. And this water-stopping layer can be applied at the same time as the water-stopping layer is formed by injecting a chemical solution at a predetermined depth below the root-cutting bottom in order to prevent boiling and heaping of the root-cutting bottom of the cut-off work.

  In addition to the above-mentioned effect, the earth retaining impermeable wall construction method according to claim 3 forms a soil mortar column by filling a soil mortar mixed with a hardener into the local excavated soil at the lower end of the excavation hole. This has the effect of reducing the discharge of construction soil from the construction site as much as possible.

  In addition to the above effect, the earth retaining impermeable wall construction method according to claim 4 forms a soil mortar column by stirring and mixing while injecting a cement-based hardener into the bottom of the excavation hole in the ground, There is an effect that the discharge of the construction residual soil from the construction site can be suppressed as much as possible.

  The earth retaining impermeable wall according to claim 5 is composed of a continuous impermeable wall formed of soil mortar columns and a steel sheet pile pressed into the upper portion of the continuous impermeable wall. The area where anti-earth pressure and water-blocking performance are required when rooting is performed is formed with steel sheet pile walls, and the area under which the water-blocking performance is mainly expected is formed with soil mortar columns. The steel sheet pile having a limit in the press-fit length can be effectively utilized by combining the two. In addition, the steel sheet pile wall used for the construction of the underground structure can be easily removed, and since only the continuous impermeable wall underneath can be left, most of the long earth retaining walls can be removed. Can be suppressed as much as possible.

  In addition to the above-mentioned effect, the earth retaining impermeable wall according to claim 6 comprises a water impermeable zone comprising a continuous impermeable wall and a water blocking layer formed by injecting a chemical into the back surface of the continuous impermeable wall. Therefore, when a steel sheet pile is press-fitted into the soil mortar, even if a crack occurs in the soil mortar wall, the water blocking layer can suppress the deterioration of the water shielding function. And this water-stopping layer has an effect that it can be applied at the same time as the water-stopping layer is formed by injecting a chemical solution to a predetermined depth below the root-cutting bottom in order to prevent boiling and heaping of the root-cutting bottom of the cut-off work. .

  In addition to the above-described effect, the soil impervious wall according to claim 7 is configured such that the soil mortar column is made of soil mortar mixed with hardener in the excavated soil. There is an effect that it can be suppressed as much as possible.

  In addition to the above-mentioned effect, the soil impervious wall according to claim 8 is constructed from a construction site because the soil mortar column is composed of a soil mortar in which a cement-based hardener is injected into the ground and mixed by stirring. There is an effect that the discharge of the remaining soil can be suppressed as much as possible.

  FIG. 1 is a schematic explanatory view showing an example of a dirt retaining wall constructed by the method of constructing a dirt retaining wall according to the present invention. A vertical section of the ground at a position crossing the retaining wall and the depth from the section. Represents. In this example, when constructing the underground structure K on the ground of the river part where cobblestone and gravel are mixed, a temporary earth retaining wall is constructed as a deadline, where α is the root bottom of the deadline Is shown.

  As shown in FIG. 1, the earth retaining water impermeable wall is composed of a water impermeable zone Za at a lower end portion and an anti-earth pressure impermeable zone Zb at an upper portion thereof. Of these, the impermeable zone Za is composed of a continuous impermeable wall 1 formed of a plurality of continuous soil mortar columns, and the anti-earth pressure impermeable zone Zb is a site buried on the continuous impermeable wall 1. It consists of a continuous earth retaining impermeable wall 4 composed of a sieving soil 2 for excavated soil and a steel sheet pile 3 that is pressed into the upper portion of the continuous impermeable wall 1 through its backfill portion. In addition, although the plate-shaped sheet pile is shown as the steel sheet pile 3 in the figure, a steel tubular sheet pile can also be used.

  And the earth retaining impermeable wall of FIG. 1 has the water stop layer 5 formed by inject | pouring a chemical | medical solution into the back surface of the continuous impermeable wall 1. This water-stopping layer 5 was extended at the same time as the water-stopping layer 6 was formed by injecting a chemical solution at a predetermined depth below the root-cutting bottom in order to prevent boiling and heaping at the base of the cut-off work. It is.

  The soil mortar column constituting the continuous impermeable wall 1 is made of a soil mortar mixed with a hardener in an on-site excavated soil, or a soil mortar in which a cement-based hardener is injected into the ground and mixed by stirring. In this way, by using the earth and sand and the ground at the construction site, the discharge of construction residual soil from the construction site can be suppressed as much as possible.

  As described above, the anti-earth pressure impermeable zone Zb as an area where the anti-earth pressure and the water shielding performance are required when rooting is performed for the construction of the underground structure K is formed of a steel sheet pile wall. The water-impervious zone Za as a region where water-impervious performance is mainly expected below is formed by the continuous water-impervious wall 1 formed of soil mortar columns. Therefore, the steel sheet pile 3 having a limit in the press-fit length can be effectively used. In addition, after the construction of the underground structure, the steel sheet pile wall used for the construction can be easily removed, and most of the long earth retaining wall can be removed by leaving only the continuous impermeable wall 1 at the bottom. It is possible to suppress adverse effects on the groundwater environment as much as possible.

  Further, by providing the water blocking layer 5 on the back surface of the continuous water blocking wall 1, even if a crack occurs in the soil mortar wall when the steel sheet pile 3 is pressed into the soil mortar, the water blocking layer 5 blocks the wall. Deterioration of water function can be suppressed.

  FIG. 2 is a process diagram for explaining the earth retaining wall construction method of the present invention, FIG. 3 is an XX sectional view of FIG. 2B, FIG. 4 is a YY sectional view of FIG. 5 to 9 are specific explanatory views of the procedure for constructing the earth retaining method shown in FIG. 1. Hereinafter, the earth retaining wall construction method according to the present invention will be described with reference to these drawings. In addition, FIG.2 (d) is shown in the direction orthogonal to each figure of Fig.2 (a)-FIG.2 (c) for easy understanding.

  As a first step, as shown in FIGS. 2 (a) to 2 (b), a step of excavating the ground to form a soil mortar column at the lower end of the excavation hole, and a site in the excavation hole on the soil mortar column, The continuous impermeable wall 1 is formed in the impermeable zone Za by sequentially repeating the step of sieving excavated soil 2 and backfilling the soil 2. The specific procedure is as follows.

  First, as shown in FIG. 5, the excavation hole is excavated by an all-swivel all-casing excavator and the excavated sediment is discharged to the ground, and then the excavated sediment S discharged to the ground is screened to remove cobbles and gravel. Then, the soil mortar is manufactured by adding cement-based hardener to the excavated soil from which the gravel has been removed and kneading. Then, as shown in FIG. 6, the soil mortar is filled in the lower part of the excavation hole by a mixer car. To form soil mortar pillars. Subsequently, the sieving soil 2 excluding cobbles and gravel is put into the excavation hole in the upper part of the soil mortar column and backfilled. In this way, the crushed soil 2 obtained by removing cobbles and gravel from the local excavated soil is backfilled to provide a countermeasure against rolling stones. This backfilling operation is performed using a backhoe 18 as shown in FIG.

  A plurality of soils connected to each other at a predetermined position below the ground by sequentially repeating a series of procedures including excavation of the excavation hole, manufacture of the soil mortar, filling of the soil mortar, and charging of the sieving soil. A continuous water blocking wall 1 made of a mortar column is formed. As a specific example, the diameter of the excavation hole is 1.2 m, the depth is 23 m, and the height of the continuous impermeable wall 1 is 6 m.

Since the excavation holes are excavated in the order indicated by d _{1 to} d ₆ in FIG. 3, the work of the next excavation hole is performed while forming the soil mortar column in the previous excavation hole. Efficiency is good.

  The all-swivel all-casing excavator shown in Fig. 5 can excavate rocks and concrete with the tip of the rotating casing, so it can penetrate the ground even if there are many obstacles such as rocks and cobblestones like a river part. Can be excavated. In FIG. 5, 10 is a crawler crane, 11 is a hammer club, 12 is a casing, 13 is a tubing device, 14 is a hydraulic unit, and S and T respectively indicate excavated earth and sand and underground rocks.

  As shown in FIG. 6, the filling of the soil mortar in the lower part of the excavation hole is performed by suspending the injection pipe 16 through the swivel 15 on the crawler crane 10 and injecting the soil mortar from the swivel 15 into the injection pipe 16 by the mixer wheel 17. To do. As described above, the soil mortar is a low-strength fluidized soil obtained by adding a cement-type hardener to kneaded soil excluding cobbles and gravel and kneading it. Alternatively, a general waste mud regenerated product soil mortar may be used after performance adjustment.

  Regarding the formation of soil mortar columns, instead of forming soil mortar columns by filling the soil mortar into the bottom of the excavation hole, the soil mortar columns are formed by stirring and mixing the cement-based hardener into the ground. You may make it do.

  As the second stage, as shown in FIG. 2 (c), the steel sheet pile 3 is pressed into the upper part of the soil mortar column through the backfilling portion where the sieving soil 2 of the on-site excavated soil is backfilled. A continuous earth retaining impermeable wall 4 is formed in the impermeable zone Zb.

  The construction work of the steel sheet pile 3 is performed using a static press-fitting machine 19 as shown in FIG. Thereby, the continuous earth retaining impermeable wall 4 as the anti-earth pressure impermeable zone Zb is formed on the upper side of the continuous impermeable wall 1. That is, a continuous earth retaining impermeable wall 4 is formed which is composed of a backfill portion in which the sieving soil 2 is backfilled and a steel sheet pile 3 that is press-fitted into the upper portion of the soil mortar.

  Finally, as shown in FIG. 2 (d), a water blocking layer 5 is formed by injecting a chemical into the back surface of the continuous impermeable wall 1. This chemical solution injection operation can be performed by a double pipe composite injection method implemented by general ground improvement. And a chemical | medical solution is inject | poured to the overlap part of the continuous impermeable wall 1 and the sheet pile 3. FIG. Since the soil mortar is hardened, there is a risk of cracking due to the press-fitting of the steel sheet pile 3, but even if a crack occurs in the wall of the soil mortar, the water blocking layer 5 may deteriorate the water shielding function. Can be suppressed. This water-stopping layer 5 is used for continuous blocking when a chemical solution is injected to a predetermined depth below the root-cutting bottom to form a water-stopping layer on one side in order to prevent boiling and heaping of the root-cutting bottom in the closing work. It can be constructed by injecting a chemical into the back of the joint between the water wall 1 and the steel sheet pile 3.

  When constructing a structure by excavating ground with a lot of gravel, a sufficient water-stopping effect can be expected by forming a soil-impregnated impermeable wall with the above structure. And this earth retaining impermeable wall can restore | restore the flow of a groundwater flow comparatively easily in the state close | similar to the present condition in the field which should avoid the influence on a groundwater flow. In other words, after completing the construction of the earth-impregnated impermeable wall as described above and finishing the frame work in the deadline, the current state of the groundwater flow is restored by pulling and removing the steel sheet pile 3 with a static press-fitting machine. Can do. In this case, the drawing work is facilitated by oscillating up and down at the beginning of each steel sheet pile 3 to break the hardened soil mortar at the joint with the lower continuous impermeable wall 1.

  As described above, the best mode for carrying out the present invention has been described in detail. However, the earth retaining wall construction method according to the present invention and the earth retaining wall formed thereby are limited to the specific examples described above. Of course, various modifications can be made without departing from the spirit of the present invention.

It is a schematic explanatory drawing which shows an example of the earth retaining impermeable wall constructed | assembled by the earth retaining wall impermeable wall construction method of this invention. It is process drawing for demonstrating the earth retaining impermeable wall construction method of this invention. It is XX sectional drawing of FIG.2 (b). It is YY sectional drawing of FIG.2 (c). It is explanatory drawing of the excavation method of an excavation hole. It is explanatory drawing of the filling method of soil mortar. It is explanatory drawing of the backfilling method of sieving soil. It is explanatory drawing of the press-fit method of a steel sheet pile.

Explanation of symbols

Za water-blocking zone Zb anti-earth pressure water-blocking zone K underground structure 1 continuous impermeable wall 2 sieving soil 3 steel sheet pile 4 continuous earth retaining impermeable wall 5 water-blocking layer 6 water-blocking layer 10 crawler crane 11 hammer club 12 casing 13 Tubing device 14 Hydraulic unit 15 Swivel 16 Injection pipe 17 Mixer car 18 Backhoe 19 Static press-fitting machine

Claims (8)

  A soil retaining wall construction method that constructs a soil retaining wall consisting of a water shielding zone at the lower end and an anti-earth pressure impermeable zone at the upper part. Forming a continuous impermeable wall in the impermeable zone by sequentially repeating the step of forming the sieving soil in the excavation hole on the soil mortar column and backfilling the soil with the on-site excavated soil. A construction method for construction of earth retaining impermeable walls characterized in that a continuous earth retaining wall is formed in the anti-earth pressure impermeable zone by inserting a steel sheet pile into the top of the soil mortar column.   After forming a continuous earth retaining impermeable wall in the anti-earth pressure impermeable zone, a waterproof layer is formed by injecting a chemical solution at least on the back of the joint between the impermeable zone and the anti-earth pressure impermeable zone The earth retaining impermeable wall construction method according to claim 1.   3. The earth retaining impermeable wall construction method according to claim 1 or 2, wherein the soil mortar column is formed by filling a soil mortar mixed with a hardener into a local excavated soil at a lower end portion of the excavation hole. .   3. The earth retaining impermeable wall construction method according to claim 1, wherein the soil mortar column is formed by stirring and mixing while injecting a cement hardening agent into the ground.   It is a earth retaining impermeable wall consisting of a water-impervious zone at the lower end and an anti-earth pressure impermeable zone at the upper part, and the impermeable zone consists of continuous impermeable walls formed by a plurality of continuous soil mortar columns, The anti-earth pressure impermeable zone consists of a sieving soil of the field excavated soil backfilled on the continuous impermeable wall, and a steel sheet pile pressed into the upper portion of the continuous impermeable wall through the backfill portion. A soil retaining wall comprising a continuous soil retaining wall composed of   6. The earth retaining impermeable wall according to claim 5, wherein the impermeable zone is composed of a continuous impermeable wall and a water blocking layer formed by injecting a chemical solution into the back surface of the continuous impermeable wall.   The soil retaining impermeable wall according to any one of claims 5 to 6, wherein the soil mortar column is made of soil mortar in which a hardener is mixed with excavated soil. 7. The earth retaining impermeable wall construction method according to claim 5, wherein the soil mortar column is made of a soil mortar in which a cement-based curing agent is injected into the ground and mixed by stirring.

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