JP2017014807A - Construction method for pile type rigid connection structure body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of easily constructing a pile type rigid connection structure body having an improved pipe, constructed in the ground where a liquefaction layer is present, and a surface solidification layer rigidly joined together.SOLUTION: A surface solidification layer 6 which includes a hardener and is unsolidified is formed on a surface of the ground G (B), a retardant which delays solidification of a solidification material is mixed with a part 6a, where at least an improvement pile 3 is constructed, of the surface solidification layer 6 (C), and before the part 6b, with which the retardant is mixed, of the surface solidification layer 6 is solidified, an improvement material is mixed with a predetermined pile construction part 13 from a non-liquefaction layer 4 of the ground G to the surface solidification layer 6 to construct an improvement pipe 3 (D). The part 6b, with which the retardant is mixed, of the surface solidification layer 6 is not solidified, so the improvement material can be easily mixed with the pile construction part 13.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for constructing a pile-type rigidly connected structure in which an improved pile and a surface solidified layer are constructed so as to be rigidly connected to each other on a ground having a liquefied layer.

  In order to improve the ground in which the liquefied layer exists, various methods for mixing and solidifying the improving material in the ground are widely performed. In order to mix the improvement material into the ground, the ground and the improvement material are forcibly stirred by rotating the stirring blade (deep mixing treatment) or driving a stirrer called a trencher (power blender method, etc.). There are a mechanical type that mixes, a high-pressure injection type that stirs and mixes the ground and the improved material by high-pressure injection of the improved material, and a combined type that uses them together. In many cases, lime, cement, or cement-based solidifying material is used as the improving material. The ground improvement is classified into pile type improvement, wall type improvement, block type improvement, etc. according to the range of the ground to be improved. Among these improvements, the material cost and the construction cost are high in the block type improvement with the largest improvement target range, and the material cost and the construction cost are low in the pile type improvement with the smallest improvement target range.

  In the pile type improvement, it is common to arrange the piles in an aligned arrangement or a staggered arrangement. However, in such an arrangement, since the unimproved region existing between the pile rows extends linearly in the row direction, the ground is likely to be liquefied. In order to solve such a problem, while arranging a plurality of improved piles with a certain regularity, it is arranged as if they were randomly arranged, and the extension length in the column direction of the unmodified areas is shortened A method of arranging piles that suppresses liquefaction of the ground has been proposed (Patent Document 1). In patent document 1, the solidification process layer is constructed in the surface part of the ground, and the fall of the improvement pile at the time of an earthquake is aimed at by connecting the heads of a plurality of improvement piles by the solidification process layer.

Japanese Patent No. 5668976

  However, in ground where uneven earth pressure such as revetment is generated, a large lateral force may be generated by liquefaction, and a solidified layer is constructed to connect the heads of improved piles as in Patent Document 1. Even if it does, when a lateral force exceeding the frictional force between the solidified layer and the upper surface of the improved pile is generated, the improved pile cannot be prevented from falling. Therefore, when liquefaction occurs in such ground, the improved pile may overturn so that the improved pile slides the upper surface against the solidified layer, and the revetment wall may be damaged by the laterally flowing ground. There is.

  Here, it is conceivable to construct the improved pile so as to penetrate the surface solidified layer after constructing the surface solidified layer, so that the improved pile is integrated with the surface solidified layer, that is, rigidly coupled. However, in this case, it is necessary to use a larger improved pile construction machine for crushing the surface solidified layer, which increases machine cost and takes time to crush the surface solidified layer. Alternatively, a dedicated machine is required to crush the surface solidified layer, and the number of work machines and work man-hours increase.

  On the other hand, after constructing the improved pile, it is conceivable that the surface solidified layer is rigidly coupled to the improved pile by constructing the surface solidified layer so as to involve the upper end of the improved pile. However, in this case, it becomes difficult to mix the solidified material in order to build the surface solidified layer on the ground around the improved pile, and there is earth and sand where the solidified material is not stirred and mixed around the improved pile. If it remains, the improved pile and the surface solidified layer cannot be rigidly connected. It is conceivable to construct a solidified layer on the improved pile, but in this case as well, it is difficult to rigidly connect the upper end surface of the improved pile and the solidified layer.

  In view of such a background, the present invention provides a method capable of easily constructing a pile-type rigidly coupled structure formed by rigidly coupling an improved pile constructed on the ground where a liquefied layer exists and a surface solidified layer. The task is to do.

  In order to solve such a problem, the present invention is formed by rigidly coupling the improved pile (3) constructed on the ground (G) where the liquefied layer (5) exists and the surface solidified layer (6). A method for constructing a pile-type rigidly bonded structure (1), in which the unsolidified surface solidified layer (6) including a solidified material is formed on the surface of the ground in order to construct the surface solidified layer (FIG. 4 ( B), FIG. 5 (B)), and a step of mixing a retarder that delays solidification of the solidified material into at least a portion (6a) in which the improved pile is constructed in the surface solidified layer (FIG. 4C), FIG. 5 (C)) and the non-liquefied layer of the ground from the surface solidified layer to construct the improved pile before the part (6b) mixed with the retarder in the surface solidified layer is solidified. Step of mixing improvement material into predetermined pile construction part (13) leading to (4) (FIG. 4 (D A structure including a FIG 5 (D)).

  The step of forming the surface solidified layer (FIGS. 4B and 5B) and the step of mixing the retarder into the surface solidified layer (FIGS. 4C and 5C) are performed simultaneously. It may be done progressively.

  According to this structure, since the part which builds the improvement pile of a surface solidification layer is not solidified when building an improvement pile, an improvement material can be easily mixed in a pile construction part. Moreover, when the improved material mixed in the pile construction part is solidified, the improved pile is rigidly coupled to the surface solidified layer.

  Moreover, in said invention, in the step (FIG.4 (C), FIG.5 (C)) which mixes the said retarder in the said surface solidified layer, the part in which the said improvement pile in the said surface solidified layer (6) is constructed | assembled The retarder may be mixed in a portion (6b) larger than (6a).

  According to this configuration, since there is an unsolidified surface solidified layer due to the mixing of the retarder on the outer periphery of the unsolidified improved pile with the improved material mixed in the pile construction part, the improved pile and the surface solidified layer were solidified. Sometimes they are securely connected securely. Moreover, even if the part which mixed the retarder and the part which construct | assembles an improved pile have shifted | deviated by the construction error, an improved pile and a surface solidified layer will be rigidly connected reliably.

  Moreover, in said invention, the step (FIG.4 (D), FIG.5 (D)) which mixes an improvement material in the said pile construction part is a part in which the said retarder is not mixed in the said surface solidified layer (6). It is good to set it as the structure performed after solidifying.

  According to this configuration, trafficability is ensured by the solidified portion of the surface solidified layer, and the improved pile can be easily constructed.

  Moreover, in order to solve said subject, this invention rigidly connects the improvement pile (3) and surface solidified layer (6) constructed | assembled in the ground (G) in which a liquefied layer (5) exists. A method for constructing a pile-type rigidly connected structure (1), which is a predetermined method for constructing the improved pile from a portion (16) where the surface solidified layer is formed to a non-liquefied layer (4) of the ground. The step of mixing the improving material into the pile building portion (13) (FIGS. 6B and 7B) and the improving material at the upper end portion (3a) where at least the surface solidified layer in the improving pile is built A step of mixing a retarder that delays solidification of the steel (FIGS. 6C and 7C), and the surface solidification before the portion (3b) mixed with the retarder in the improved pile is solidified. In order to build a layer, the solidified surface solidified layer (6) including a solidified material is formed on the surface of the ground. Step (FIG. 6 (D), the FIG. 7 (D)) which is configured to include a.

  Note that the step of mixing the improving material into the pile building portion and the step of mixing the retarder into the pile building portion may be performed simultaneously.

  According to this structure, since the part which builds the surface solidified layer of an improved pile is not solidified when building a surface solidified layer, a surface solidified layer can be formed easily. Further, when the surface solidified layer is solidified, the surface solidified layer is rigidly connected to the improved pile.

  Moreover, in said invention, in the step (FIG.6 (C), FIG.7 (C)) which mixes the said retarder in the said improvement pile, the upper end part in which the said surface solidification layer in the said improvement pile (3) is formed It is good to set it as the structure which mixes the said retarder in the part (3b) deeper than (3a).

  According to this configuration, since the unsolidified improved pile exists due to the mixing of the retarder below the unsolidified surface solidified layer, when the surface solidified layer and the improved pile are solidified, both are securely bonded firmly. Moreover, even when the height of the lower end of the part mixed with the retarder due to construction error is higher than the planned height, the surface solidified layer is securely bonded to the unsolidified part of the improved pile.

  Moreover, in said invention, the step (FIG. 6 (D), FIG.7 (D)) which forms the said surface solidified layer is performed after the part in which the said retarder in the said improvement pile is not mixed solidifies. It is good to do.

  According to this structure, since the part in which the retarder of the improved pile is not mixed is suppressed from being damaged during the formation work of the surface solidified layer, it is possible to prevent the quality deterioration of the pile-type rigid coupling structure.

  In the above invention, in the step of forming the surface solidified layer (FIG. 4B, FIG. 6D), the solidified material is mixed into the surface layer of the ground (G), and the shallow layer improvement layer is used. The surface solidified layer (6) can be formed.

  According to this structure, the material cost and construction cost for forming a surface solidification layer can be suppressed.

  In the above invention, in the step of forming the surface solidified layer (FIGS. 5B and 7D), a solidified layer material in which the solidified material is mixed on the surface of the ground (G) is used. It can be set as the structure which laminates | stacks and forms the said surface solidified layer (6) newly.

  According to this configuration, since the solidified material is not mixed on site, a surface solidified layer having a uniform quality (strength) can be constructed.

  As described above, according to the present invention, there is provided a method capable of easily constructing a pile-type rigidly coupled structure formed by rigidly coupling an improved pile constructed on the ground where a liquefied layer exists and a surface solidified layer. Can do.

Sectional drawing of the pile-type rigid coupling structure which concerns on 1st Embodiment (II sectional drawing in FIG. 2) Plan view of the pile-type rigid joint structure shown in FIG. The principal part perspective view of the pile-type rigid coupling structure shown in FIG. Explanatory drawing of the construction method of the pile type rigid coupling structure shown in FIG. Explanatory drawing of the construction method of the pile type rigid joint structure concerning a 2nd embodiment Explanatory drawing of the construction method of the pile type rigid joint structure concerning a 3rd embodiment Explanatory drawing of the construction method of the pile type rigid joint structure concerning a 4th embodiment

  Hereinafter, several embodiments of the pile-type rigid coupling structure 1 and the construction method thereof according to the present invention will be described with reference to the drawings.

<< First Embodiment >>
As shown in FIG. 1, the pile-type rigid coupling structure 1 according to the present embodiment is applied to the ground G that is partitioned by the revetment structure 2 and in which the liquefied layer 5 exists on the non-liquefied layer 4. Yes. Revetment structure 2 is composed of a like vertically installed steel sheet pile or steel sheet pile at the boundary between land and sea, it is entered with a predetermined embedment length L ₁ in the non-liquefaction layer 4. The revetment structure 2 may be a self-supporting type, a tie rod type, or other types. Since the earth pressure is acting on the upper part of the revetment structure 2 and the liquefaction layer 5 is liquefied, the earth pressure is increased and the revetment structure 2 may be damaged. Has been applied.

  On the ground G at a position away from the revetment structure 2, a tank T that is a heavy structure is constructed. In addition, although illustration is abbreviate | omitted, the tank T is supported by the pile foundation containing the pile which reaches the non-liquefaction layer 4. Therefore, when the liquefied layer 5 is liquefied during an earthquake, the vertical load of the tank T can be supported by the pile foundation, but when the liquefied layer 5 flows sideways to the sea side, the foundation pile tilts and the tank T also moves. There is a risk of doing. Therefore, a pile-type rigid coupling structure 1 is constructed between the tank T and the revetment structure 2 in order to prevent lateral flow of the liquefied layer 5.

  The pile-type rigidly connected structure 1 is constructed at the upper part of the ground G so as to be connected to the plurality of improved piles 3 constructed on the ground G and the plurality of improved piles 3 by being rigidly coupled to the heads of the respective improved piles 3. It is a pile-type structure provided with the surface solidified layer 6.

The improved pile 3 is a ground improved pile in which compressive strength is increased by mixing the lime, cement, cement-based improving material into the ground G and improving the ground G, and a predetermined penetration length L in the non-liquefaction layer 4 It has entered with _two . Thereby, the lower end of the improved pile 3 is rigidly joined to the non-liquefaction layer 4. The improved pile 3 is constructed by a known method such as a mechanical stirring method such as a deep mixing process or a power blender method, a mechanical stirring combined use type high pressure injection method, and a high pressure injection method. In the example of illustration, the pile type rigid coupling structure 1 is formed in the circular cross section (refer FIG. 2).

  As shown in FIG. 2, the improved piles 3 are arranged as if they were random. This arrangement is described in Patent Document 1 described above, and only the outline will be described here. An X direction and a Y direction orthogonal to each other are set on the plane of the ground G to be improved. The arrangement of the improved piles 3 is four improved piles arranged in a total of four points, two rows having a predetermined X-direction interval Dx in the X direction and two rows having a predetermined Y-direction interval Dy in the Y direction. 3 is defined as one pile group P, and a plurality of pile groups P are determined according to a predetermined law described later.

  The law of arranging a plurality of pile groups P is as follows. First, let the center of each pile group P be a group center C. The pile group P arranged adjacent to one pile group P in the X direction has a distance (2 · Dx) that is twice the X-direction interval Dx in the X direction from the group center C of the one pile group P. The lens is arranged such that a position at a distance (0.5 · Dy) 0.5 times the Y-direction interval Dy is the group center C in the Y direction. A pile group P arranged adjacent to one pile group P in the Y direction is a distance 0.5 times the X-direction interval Dx in the X direction from the group center C of the one pile group P (0.5 · Dx) is arranged such that a position at a distance (2.Dy) twice the Y-direction interval Dy in the Y direction is the group center C.

  By arrange | positioning according to such a law, the improvement pile 3 is arrange | positioned like random, and the high liquefaction suppression effect is exhibited because the extension length of the row direction of an unimproved area | region becomes short.

  The improved pile 3 is not limited to such an arrangement, but is a lattice shape (alignment arrangement) that is equally spaced in two directions orthogonal to each other on the horizontal plane, or a continuous rhombic apex that combines two congruent equilateral triangles. It may be arranged in (staggered arrangement).

  The surface solidified layer 6 is formed as a shallow layer improved layer in which the compressive strength is increased by improving the ground G by mixing lime, cement, or cement-based solidified material into the surface layer of the ground G. The surface solidified layer 6 is formed by forced stirring and mixing of the solidified material by the backhoe and the ground G (earth and sand), forced stirring and mixing by a stirring machine equipped with a rotary type stabilizer, or the like. Alternatively, the surface solidified layer 6 is newly formed by laminating or placing a solidified layer material such as solidified material mixed soil or concrete mixed with lime, cement, or cement-based solidified material on the surface of the ground G. May be.

  In addition, the solidification material used for formation of the surface solidified layer 6 and the improvement material used for construction of the improved pile 3 may be the same material or different materials. In this specification, in order to distinguish the solidification material used for formation of the surface solidification layer 6 and the solidification material used for construction of the improvement pile 3, the former is called solidification material and the latter is called improvement material.

  As shown in FIG. 3, a retarder is mixed in a portion 6 b larger than the cross section (diameter) of the improved pile 3 at a position corresponding to the improved pile 3 in the surface solidified layer 6. The improved pile 3 is formed through the surface solidified layer 6 before the portion 6b of the surface solidified layer 6 mixed with the retarder is solidified, and the upper end 3a of the portion 6b of the surface solidified layer 6 mixed with the retarder. It is constructed so that (head) is surrounded. Due to the solidification of the unsolidified improved pile 3 and the unsolidified portion 6b mixed with the retarder of the surface solidified layer 6, the improved pile 3 and the surface solidified layer 6 are integrated over the thickness t of the surface solidified layer 6. Are rigidly connected to each other.

  The pile-type rigidly connected structure 1 configured as described above is configured such that the lower ends of the plurality of improved piles 3 and the non-liquefied layer 4 are rigidly joined, and the upper end portions 3a of the plurality of improved piles 3 and the surface solidified layer 6 are rigid. A ramen structure is formed by joining. That is, the pile-type rigidly connected structure 1 has high rigidity with respect to the lateral force caused by the earth pressure and the liquefaction of the liquefied layer 5 at the time of earthquake, and the improved pile 3 is difficult to fall down. It is possible to effectively suppress the lateral flow.

  Next, with reference to FIG. 4, the construction method of the pile type rigid coupling structure 1 of the said structure is demonstrated.

  As shown in FIG. 4A, first, the ground G partitioned by the revetment structure 2 (see FIG. 1) is leveled and flattened. The imaginary line in the figure shows the pile construction from the surface solidified layer 6 to the surface solidified layer 6 in the ground G and the solidified layer 6 (surface layer) from which the improved pile 3 is constructed to the non-liquefied layer 4. Part 13 is shown.

  Next, as shown in FIG. 4 (B), a solidifying material is mixed into the surface layer portion 16 of the ground G using an appropriate construction machine to construct an unsolidified surface solidified layer 6. Then, the improved pile 3 (pile construction part 13) is positioned on the surface solidified layer 6.

  In this specification, since the basic construction work of the surface solidified layer 6 is completed when the solidified material is mixed into the surface layer portion 16 of the ground G, the solidified material is in a state before solidified. However, this portion 16 is called the surface solidified layer 6. Similarly, since the basic construction work of the improved pile 3 is completed when the improving material is mixed into the pile building portion 13 of the ground G, the pile building portion 13 is in a state before the improving material is solidified. Is called improved pile 3.

  After positioning the improved pile 3, before the solidified material of the surface solidified layer 6 is solidified, at least the improved pile 3 in the surface solidified layer 6 is constructed using an appropriate construction machine as shown in FIG. 4C. A retarder that delays the solidification of the solidifying material is mixed in the portion 6a to be formed. As shown in the drawing, the portion 6b into which the retarder is mixed may be larger in plan view than the portion 6a in which the improved pile 3 is constructed.

  The step of forming the surface solidified layer 6 shown in FIG. 4B and the step of mixing the retarder into the surface solidified layer 6 shown in FIG. 4C may be performed simultaneously. That is, before the solidified material is mixed into the surface layer portion 16 of the ground G, the improved pile 3 is positioned, and when the surface solidified layer 6 shown in FIG. A retarder may be mixed into the ground G together with the solidifying material in the portion 6b to be mixed, or a solidified material mixed with the retarding agent may be mixed into the ground G.

  Thereafter, before the portion 6b mixed with the retarder of the surface solidified layer 6 is solidified, as shown in FIG. 4D, the surface solidified layer 6 is used on the surface solidified layer 6 by using an appropriate construction machine. The improvement material is mixed into the pile construction portion 13 in the ground G from the portion 6b in which the retarder is mixed, and the improvement pile 3 is constructed. Under the present circumstances, since the part 6a which should construct | assemble the improvement pile 3 of the surface solidified layer 6 is not solidified, an improvement material can be easily mixed in the pile construction part 13. FIG.

  The improved pile 3 may be constructed by any method. However, since a heavy machine is usually used in any method, the improved pile construction work is performed after the portion of the surface solidified layer 6 where the retarder is not mixed is solidified. It is good to do. Thereby, the trafficability of the ground G is ensured and a heavy machine can be carried in on the ground G as it is.

  In the state where the improving material is mixed in the pile building portion 13, as shown in FIG. 4 (D), the upper end portion 3a of the unsolidified improved pile 3 is solidified without being mixed with the retarder of the surface solidified layer 6. The retarder of the surface solidified layer 6 is mixed and the unsolidified portion 6b exists around the upper end 3a of the improved pile 3. The improved pile 3 and the surface solidified layer 6 are solidified by solidifying the improved pile 3 and the portion 6b of the surface solidified layer 6 mixed with the passage of time, so that the upper end 3a of the improved pile 3 is integrated. The pile-type rigid coupling structure 1 rigidly coupled to the surface solidified layer 6 is constructed.

  In addition, as shown in FIG. 4C, when the retarder is mixed in a portion 6 b larger than the portion 6 a where the improved pile 3 is constructed in the surface solidified layer 6, the portion 6 b in which the retarder is mixed due to a construction error Even if the portion 6a for constructing the improved pile 3 is deviated, the improved pile 3 and the surface solidified layer 6 are securely bonded firmly.

<< Second Embodiment >>
Next, with reference to FIG. 5, the other construction method regarding the pile type rigid coupling structure 1 of 1st Embodiment is demonstrated. In addition, the same code | symbol is attached | subjected to the member and site | part which are common in the said embodiment, and the overlapping description is abbreviate | omitted. The same applies to other embodiments described below.

  In this embodiment, as shown in FIG. 5 (A), the portion 16 to construct the surface solidified layer 6 indicated by the imaginary line is set on the ground surface (on the ground G), not on the surface layer of the ground G. ing. In order to construct the pile-type rigidly connected structure 1, as shown in FIG. 5 (B), a solidified layer material mixed with a solidified material is first laminated on the surface of the ground G, and an unsolidified surface on the ground G A solidified layer 6 is newly formed. As described above, the solidified layer material is solidified material mixed soil, concrete, or the like mixed with lime, cement, or cement-based solidified material. After laminating the solidified layer material, the improved pile 3 is positioned on the surface solidified layer 6.

  Then, before the surface solidified layer 6 is solidified, the improved pile 3 is positioned on the ground G, and as shown in FIG. 5 (C), using an appropriate construction machine on the surface solidified layer 6, A retarder that delays the solidification of the solidified material is mixed in at least a portion 6a of the surface solidified layer 6 where the improved pile 3 is constructed. Similar to the first embodiment, the portion 6b into which the retarder is mixed may be larger in plan view than the portion 6a in which the improved pile 3 is constructed, as illustrated.

  Also in the present embodiment, the step of forming the surface solidified layer 6 shown in FIG. 5B and the step of mixing the retarder into the surface solidified layer 6 shown in FIG. May be done. That is, the improved pile 3 is positioned before the solidified layer material is laminated on the surface of the ground G, and when the surface solidified layer 6 shown in FIG. A solidified layer material in which a retarder is mixed together with the solidified material may be laminated on the ground G in the portion 6b to be formed.

  Subsequent work steps shown in FIG. 5D are the same as those in the first embodiment. Also in this embodiment, it is good to perform an improved pile construction work after the part in which the retarder is not mixed in the surface solidified layer 6 is solidified. Even if the pile-type rigid coupling structure 1 is constructed in this way, the same effects as those of the first embodiment can be obtained.

«Third embodiment»
Next, with reference to FIG. 6, the construction method of the pile type rigid coupling structure 1 which has the structure which changed 1st Embodiment partially is demonstrated.

  In this embodiment, as shown in FIG. 6 (A), the portion 16 for constructing the surface solidified layer 6 indicated by an imaginary line is set on the surface layer of the ground G as in the first embodiment. In order to construct the pile-type rigidly connected structure 1, first, the improved pile 3 is positioned on the ground G, and then an appropriate construction machine is used on the ground G as shown in FIG. Then, the improving material is mixed into the pile building portion 13 in the ground G, and the unsolidified improved pile 3 is built.

  Thereafter, before the improved pile 3 is solidified, as shown in FIG. 6C, a retarder that delays the solidification of the improved material is mixed into the upper end portion 3a where at least the surface solidified layer 6 in the improved pile 3 is built. To do. The portion 3b into which the retarder is mixed may be deeper than the upper end 3a on which the surface solidified layer 6 is constructed as shown.

  Also in the present embodiment, the step of forming the improved pile 3 shown in FIG. 6 (B) and the step of mixing the retarder into the upper end portion 3a of the improved pile 3 shown in FIG. It may be done progressively. That is, when the improved pile 3 shown in FIG. 6B is formed, the retarder may be mixed into the ground G together with the improver at the portion 3b where the retarder should be mixed.

  Then, before the part 3b mixed with the retarder of the improved pile 3 is solidified, the retarder of the improved pile 3 is used on the ground G by using an appropriate construction machine as shown in FIG. The solidified material is mixed into the surface layer of the ground G including the mixed portion 3b, and the surface solidified layer 6 is constructed. Under the present circumstances, since the upper end part 3a which should build the surface solidification layer 6 of the improvement pile 3 is not solidified, a solidification material can be easily mixed in the part 16 which should build the surface solidification layer 6 of the ground G.

  The operation of mixing the solidifying material into the surface layer of the ground G shown in FIG. 6 (D) may be performed after the portion of the improved pile 3 where the retarder is not mixed is solidified. By performing at such a timing, it is possible to prevent the improved pile 3 being solidified from being damaged by an erroneous operation of the construction machine in which the solidified material is mixed into the surface layer.

  Even if the pile-type rigidly connected structure 1 is constructed in this way, the surface solidified layer 6 and the portion 3b mixed with the retarder of the improved pile 3 are solidified over time, as in the above embodiment. The solidified layer 6 and the improved pile 3 are integrated, and the pile-type rigid coupling structure 1 in which the improved pile 3 is rigidly coupled to the surface solidified layer 6 is constructed.

  Further, when the retarder is mixed into the improved pile 3 shown in FIG. 6C, the retarder is mixed into the portion 3b deeper than the upper end portion 3a where the surface solidified layer 6 in the improved pile 3 is formed. Since the unsolidified improved pile 3 exists by mixing of the retarder below the unsolidified surface solidified layer 6 constructed in FIG. 6D, the retarders of the surface solidified layer 6 and the improved pile 3 are mixed. When the portion 3b is solidified, the two are securely bonded firmly. Further, even when the height of the lower end of the portion 3b in which the retarder of the improved pile 3 is mixed due to construction errors is higher than the planned height, the surface solidified layer 6 is securely bonded firmly to the unsolidified portion 3b of the improved pile 3 To do.

<< Fourth Embodiment >>
Finally, with reference to FIG. 7, the other construction method regarding the pile type rigid coupling structure 1 of the structure similar to 3rd Embodiment is demonstrated.

  The construction method of the present embodiment has the same differences with respect to the third embodiment as the differences of the second embodiment with respect to the first embodiment. That is, in this embodiment, as shown in FIG. 7A, a portion 16 for constructing the surface solidified layer 6 indicated by an imaginary line is set on the surface of the ground G as in the second embodiment. . In constructing the pile-type rigidly connected structure 1, the improved pile 3 is positioned on the ground G, and the improved material is mixed into the pile building portion 13 in the ground G as shown in FIG. The procedure for constructing the improved pile 3 is the same as in the third embodiment. In the present embodiment, since the surface solidified layer 6 is newly formed on the surface of the ground G, the upper end portion 3 a where the surface solidified layer 6 in the improved pile 3 is constructed is the upper end surface of the improved pile 3.

  Thereafter, before the improved pile 3 is solidified, as shown in FIG. 7C, a delay that delays the solidification of the improved material to the portion 3b including the upper end surface in which at least the surface solidified layer 6 is formed in the improved pile 3. Mix the agent. In the present embodiment, in particular, the portion 3b of the improved pile 3 into which the retarder is mixed may be deeper than the upper end 3a where the surface solidified layer 6 is constructed, and the retarder may be mixed in a range over a predetermined depth. Also in the present embodiment, the step of forming the surface solidified layer 6 shown in FIG. 7B and the step of mixing the retarder into the surface solidified layer 6 shown in FIG. May be done.

  Thereafter, before the portion 3b mixed with the retarder of the improved pile 3 is solidified, as shown in FIG. 7D, the solidified layer material mixed with the solidified material is laminated on the surface of the ground G. Thus, the surface solidified layer 6 is newly formed on the ground G. Even if the pile-type rigid coupling structure 1 is constructed in this way, the same effects as those of the third embodiment can be obtained.

  This is the end of the description of specific embodiments, but the present invention is not limited to these embodiments. For example, the specific shape, arrangement, quantity, dimensions, work procedure, and the like of each element of the above embodiment can be changed as appropriate without departing from the spirit of the present invention. Moreover, you may combine the structure of the said Example. Furthermore, all the elements and work procedures of the pile-type rigid coupling structure 1 according to the present invention shown in the above embodiment are not necessarily essential, and can be selected as appropriate.

1 Pile-type rigid joint structure 3 Improved pile 3a Upper end (part where non-liquefied layer is formed)
3b Part where retarder is mixed 4 Non-liquefied layer 5 Liquefied layer 6 Surface solidified layer 6a Part where improved pile is constructed 6b Part where retarder is mixed 13 Pile constructing part where improved pile is constructed 16 Surface solidified layer Parts to build G Ground

Claims (8)

It is a construction method of a pile-type rigidly coupled structure formed by rigidly coupling an improved pile constructed on the ground where a liquefied layer exists and a surface solidified layer,
Forming the unsolidified surface solidified layer containing a solidified material on the surface of the ground to build the surface solidified layer;
Mixing a retarder that delays solidification of the solidified material into at least a portion of the surface solidified layer where the improved pile is constructed;
In order to build the improved pile before the portion mixed with the retarder in the surface solidified layer is solidified, an improvement material is applied to a predetermined pile building portion from the surface solidified layer to the non-liquefied layer of the ground. A method for constructing a pile-type rigidly coupled structure, comprising: a step of mixing.   The pile-type rigid according to claim 1, wherein in the step of mixing the retarder into the surface solidified layer, the retarder is mixed into a portion of the surface solidified layer that is larger than a portion where the improved pile is constructed. How to build a binding structure.   The pile-type rigid coupling according to claim 1 or 2, wherein the step of mixing the improving material into the pile building portion is performed after the portion of the surface solidified layer not mixed with the retarder is solidified. How to build a structure. It is a construction method of a pile-type rigidly coupled structure formed by rigidly coupling an improved pile constructed on the ground where a liquefied layer exists and a surface solidified layer,
In order to construct the improved pile, a step of mixing an improved material into a predetermined pile building portion from the non-liquefied layer of the ground to the portion where the surface solidified layer is formed,
Mixing a retarder that delays the solidification of the improved material into the upper end of at least the surface solidified layer in the improved pile; and
Forming the unsolidified surface solidified layer including the solidified material on the surface of the ground to form the surface solidified layer before the portion of the improved pile mixed with the retarder is solidified. A method of constructing a pile-type rigidly connected structure characterized by the above.   5. The pile-type rigid according to claim 4, wherein in the step of mixing the retarder into the improved pile, the retarder is mixed into a portion deeper than an upper end portion of the improved pile where the surface solidified layer is formed. How to build a binding structure.   The construction of the pile-type rigid coupling structure according to claim 4 or 5, wherein the step of forming the surface solidified layer is performed after a portion of the improved pile in which the retarder is not mixed is solidified. Method.   In the step of forming the surface solidified layer, the solidified material is mixed into a surface layer of the ground to form the surface solidified layer formed of a shallow layer improvement layer. The construction method of the pile type rigid coupling structure as described in one term.   In the step of forming the surface solidified layer, the surface solidified layer is newly formed by laminating the solidified layer material mixed with the solidified material on the surface of the ground. The construction method of the pile type rigid coupling structure as described in any one of 6.

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