Uneven settlement correction drain and uneven settlement correction method

Abstract

To correct uneven settlement of a structure in a short period of time.SOLUTION: An uneven settlement correction drain 100 comprises a drainage hole 120 constructed vertically from the ground surface immediately below and around a structure 10 at a side of the structure 10 that unevenly settles due to consolidation settlement of a clay soil layer 50 where the amount of settlement is smaller, and a plurality of water channels 150 extending radially laterally from the drainage hole 120 and constructed in the clay soil layer 50 at intervals in the vertical direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a drain for correcting differential settlement and a method for correcting differential settlement. [Background technology]

[0002] Patent Document 1 discloses a technique for correcting uneven settlement of tanks during operation. In this prior art, a deep well is dug in the ground near the unsinking side of the unevenly subsided tank, and groundwater is discharged from the deep well to lower the groundwater in the ground, which in turn causes the consolidated layer to sink and at the same time corrects the unevenly subsided tank to a horizontal position.

[0003] Patent Document 2 discloses a technology related to a ground improvement method using drainage. In this prior art, a small hole is excavated to a specified depth, and a reamed hole is excavated that spreads horizontally from the small hole, and the excavated soil in the reamed hole is replaced with a mixture of granular material and a water-absorbent resin that absorbs seawater and shrinks, constructing a permeable layer that spreads horizontally underground. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 53-089014 [Patent Document 2] Japanese Patent Application Publication No. 03-132512 Summary of the Invention [Problem to be solved by the invention]

[0005] Sand drain and paper drain methods are known as methods for promoting consolidation of clayey soil layers. These methods aim to promote consolidation of clayey soil layers by shortening the drainage distance by constructing multiple drainage paths (drains) in the clayey soil layer that are only vertical. However, there is a demand for a method to correct uneven settlement of structures in a shorter period of time.

[0006] In view of the above, an object of the present invention is to correct uneven settlement of a structure in a short period of time. [Means for solving the problem]

[0007] The first aspect is an uneven settlement correction drain comprising a drainage hole constructed vertically from the ground surface at least one of immediately below a structure that has settled unevenly due to consolidation settlement of a clayey soil layer and around the structure on the side where the amount of settlement is smaller, and a plurality of water channels extending radially laterally from the drainage hole and constructed in the clayey soil layer at intervals in the vertical direction.

[0008] In the first embodiment, by constructing a horizontal water path (drainage route) in addition to vertical drainage holes, the drainage of local pore water in the clayey soil layer on the side of the structure where the settlement amount is smaller is promoted compared to the case where only vertical drainage holes are constructed, and as a result, the local consolidation settlement of the clayey soil layer is promoted. Therefore, the uneven settlement occurring in the structure can be corrected in a short time.

[0009] A second aspect is the differential settlement correction drain according to the first aspect, in which the water path is filled with coarse granular material.

[0010] In the second aspect, since the water path is filled with coarse granular material, the water path is prevented from being blocked as the consolidation progresses.

[0011] A third aspect is a method for correcting uneven settlement of a structure which has undergone uneven settlement due to consolidation settlement of a clayey soil layer, comprising the steps of constructing drainage holes vertically from the ground surface at least one of immediately below the structure and around the structure on the side where the settlement is smaller, constructing a plurality of water paths in the clayey soil layer which extend radially from the drainage holes at intervals in the vertical direction and extend laterally, draining the interstitial water in the clayey soil layer through the drainage holes to promote the consolidation settlement of the clayey soil layer on the side where the settlement is smaller, and stopping the drainage of the interstitial water when the settlement of the structures becomes equal.

[0012] In the third aspect, by constructing a horizontal water path (drainage route) in addition to vertical drainage holes, the drainage of local pore water in the clay layer on the side of the structure where the settlement amount is smaller is promoted compared to the case where only vertical drainage holes are constructed, and as a result, local consolidation settlement of the clay layer is promoted. Therefore, uneven settlement occurring in the structure can be corrected in a short time.

[0013] A fourth aspect is a method for correcting uneven settlement of a structure as described in the third aspect, in which the step of constructing the water path includes a step of fracturing and injecting a self-decomposing viscous fluid mixed with coarse granular material into the clayey soil layer through the drainage hole, and a step of discharging the viscous fluid whose viscosity has decreased over time through the drainage hole while leaving the coarse granular material in the water path.

[0014] In the fourth aspect, since the water path is filled with coarse granular material, the water path is prevented from being blocked as the consolidation progresses.

[0015] A fifth aspect is a method for correcting uneven settlement of a structure as described in the third aspect, in which the step of constructing the water paths includes the steps of constructing a plurality of water paths in the clayey soil layer at intervals in the vertical direction, the water paths extending radially laterally from the drainage holes by a high-pressure jet mixing method, injecting a self-decomposing viscous fluid mixed with coarse granular material into the water paths from the drainage holes, and discharging the viscous fluid whose viscosity has decreased over time from the drainage holes while leaving the coarse granular material in the water paths.

[0016] In the fifth aspect, since the water path is filled with coarse granular material, the water path is prevented from being blocked as the consolidation progresses. Effect of the Invention

[0017] According to the present invention, uneven settlement of a structure can be corrected in a short period of time. [Brief description of the drawings]

[0018] [Figure 1] Schematic diagram of an uneven settlement correction drain, (A) is a plan view, and (B) is a side view. [Diagram 2] 1A and 1B are side views showing a schematic view of a structure according to a first application example, in which (A) is a view showing a state before differential settlement occurs, and (B) is a view showing a state after differential settlement. [Diagram 3] 1A is a plan view and FIG. 1B is a side view showing a state in which an uneven settlement correction drain is provided to correct an unevenly settled structure in the first application example. [Figure 4] FIG. 11 is a side view showing a schematic diagram of an uneven settlement correction drain installed to correct an unevenly settled structure in the first application example, where (A) shows the state before correction, and (B) shows the state after correction. [Diagram 5] 11A and 11B are side views showing a schematic view of a structure according to a second application example, in which (A) is a view showing a state before differential settlement occurs, and (B) is a view showing a state after differential settlement. [Figure 6] FIG. 11 is a side view showing a schematic diagram of an uneven settlement correction drain provided to correct an unevenly settled structure in the second application example, where (A) shows the state before correction, and (B) shows the state after correction. [Figure 7] FIG. 2 is a schematic diagram showing a drainage path from a differential settlement correction drain. [Figure 8] FIG. 13 is an explanatory diagram for explaining the drainage distance of an uneven settlement correction drain. [Figure 9] 1 is a graph showing the relationship between the degree of compaction U and the time coefficient Tv. [Figure 10] FIG. 2 is a plan view corresponding to FIG. 1(A) and showing another example of a water path. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] <Embodiment> The uneven settlement correction drain of this embodiment will be described. The two directions perpendicular to the horizontal direction are the X direction and the Y direction, which are indicated by the arrows X and Y, respectively. The vertical direction perpendicular to the X direction and the Y direction is the Z direction, which is indicated by the arrow Z.

[0020] [composition] First, the structure of the differential settlement correction drain will be described.

[0021] As shown in Figures 1(A) and 1(B), the differential settlement correction drain 100 is configured to have a drainage hole 120 constructed vertically in the ground G, and a plurality of water paths 150 extending horizontally from the drainage hole 120. Note that some of the water paths 150 are branched.

[0022] Here, Figures 1(A) and 1(B) are intended to illustrate the structure of the drain hole 120 and the water path 150 of the uneven settlement correction drain 100 in an easy-to-understand manner, but are not intended to be accurate. This also applies to the other figures.

[0023] As shown in Fig. 1(A), in a plan view, a plurality of water paths 150 extend radially in the lateral direction from the drainage hole 120. Also, as shown in Fig. 1(B), the water paths 150 are constructed at intervals in the vertical direction.

[0024] In this embodiment, each water path 150 is filled with coarse granular material 160. Note that "coarse granular material" refers to soil particles consisting of either or both of sand with a particle size of 0.075 mm to 2.0 mm and gravel with a particle size of 2.0 mm to 75 mm. In this example, silica sand, more specifically No. 3 silica sand (diameter of about 1 mm), is used as the coarse granular material 160.

[0025] In addition, the coarse-grain material 160 is omitted from the drawings other than FIG. 1 and FIG. 8 described later in order to avoid the drawings becoming complicated and difficult to see.

[0026] [Construction method] Next, a method for constructing the differential settlement correction drain 100 will be described.

[0027] (First construction method) In the first construction method, a fracturing and injection method is used to construct the water path 150, in which the ground G is fractured and a chemical solution is injected. In this embodiment, the chemical solution injected by fracturing the ground G is a self-decomposing viscous fluid M mixed with a coarse grain material 160.

[0028] Here, the term "self-decomposing" means that the viscous fluid M is decomposed without the addition of a decomposing agent, and is decomposed mainly by the action of microorganisms. By self-decomposing, the viscosity of the viscous fluid M is reduced to the same level as that of water. In other words, the viscosity of the self-decomposing viscous fluid M of this embodiment is reduced to the same level as that of water with the passage of time.

[0029] The material having self-degradability used for the viscous fluid M is preferably a biodegradable material, more preferably a solution (such as an aqueous solution) of natural polysaccharides. If the material is of natural origin, the components generated by decomposition will not pollute the soil even if they are dispersed into the soil. Note that "biodegradable" refers to a property of a substance being decomposed by microorganisms. In this embodiment, the viscous fluid M is a material whose main component is a natural polysaccharide such as guar gum, specifically, a restar agent is used. In addition, the initial viscosity of the viscous fluid M in this embodiment is set to about 1000 cp, but is not limited to this.

[0030] The fracturing injection method is an existing technique, so it will be explained briefly. In this embodiment, the water path 150 is constructed by utilizing the technique disclosed in JP 2012-162919 A.

[0031] First, drainage hole 120 is drilled using a boring machine or the like, and an injection pipe with an injection hole formed therein is inserted into the drilled drainage hole 120.

[0032] Next, viscous fluid M mixed with coarse granular material 160 is injected into the ground G from the injection pipe. The injected viscous fluid M creates fissures in the ground G, forming water paths 150 extending horizontally from the injection hole of the water injection pipe. The viscous fluid M mixed with the coarse granular material 160 remains inside the water paths 150. The water paths 150 are constructed radially in the horizontal direction in a plan view. Each water path 150 branches out and extends up, down, left, and right along the fissures. The injection pipe is pulled out after the water paths 150 have been formed.

[0033] As described above, the viscous fluid M is decomposed by microorganisms without the addition of a decomposing agent, and becomes as viscous as water. Then, the viscous fluid M, which has become as viscous as water, is discharged from the drainage hole 120, and the coarse granular material 160 remains in the water path 150. In other words, the water path 150 is filled with the coarse granular material 160.

[0034] In addition, the drainage hole 120 may be filled with the coarse granular material 160 by pressing a viscous fluid M mixed with the coarse granular material 160 into the drainage hole 120, and the viscous fluid M, which has similar viscosity to that of water, is then discharged from the drainage hole 120, leaving behind the coarse granular material 160.

[0035] (Second construction method) In the second construction method, a high-pressure jet mixing method is used to construct the water path 150. The high-pressure jet mixing method is an existing technology, so it will be explained briefly.

[0036] First, the drainage hole 120 is drilled using a boring machine or the like, and a rod with an injection nozzle attached to the tip is inserted into the drainage hole 120. Next, fresh water or muddy water is sprayed laterally from the injection nozzle to create a water path 150.

[0037] Here, in a typical high-pressure jet mixing method, the jet nozzle is rotated while jetting, but in this method, the jet nozzle is not rotated, and fresh water or muddy water is jetted to construct water paths 150 in the horizontal direction. Then, with the jetting stopped once, the angle of the jet nozzle is changed (the jet nozzle is rotated a predetermined angle and stopped), and jetting is started again, thereby constructing multiple water paths 150 radially. Also, by changing the depth of the jet nozzle, water paths 150 are constructed at intervals in the vertical direction. Once the water paths 150 have been constructed, the rod is pulled out, and a viscous fluid M mixed with coarse grain material 160 is pressed in through the drainage hole 120.

[0038] The viscous fluid M, which has become as viscous as water due to aging, is discharged from the drainage hole 120, and the coarse granular material 160 remains in the water path 150 and the drainage hole 120. In other words, the water path 150 is filled with the coarse granular material 160.

[0039] In the case of the high pressure jet mixing method, each water path 150 does not branch or branches little. In the case of the high pressure jet mixing method, the drainage hole 120 is also filled with the coarse granular material 160 as described above.

[0040] <First application example> Next, a first application example in which the differential settlement correction drain 100 is used to correct the uneven settlement of the structure 10 will be described.

[0041] [Structures / ground] First, the structure 10 and the ground G will be described.

[0042] As shown in Fig. 2(A), the structure 10 of this application example is a spread foundation structure. The structure 10 may be of any structure. The ground G on which the structure 10 is constructed has a clayey soil layer 50 below a surface layer (not shown). In other words, the structure 10 is a spread foundation structure with the clayey soil layer 50 as a supporting layer.

[0043] FIG. 2(B) shows a state in which the clayey soil layer 50 has settled due to consolidation during construction of the structure 10 or during the period of use after completion, resulting in uneven settlement of the structure 10.

[0044] Consolidation settlement is a phenomenon in which the pore water in a clayey soil layer is discharged and the ground sinks when a vertical load is continuously applied to the clayey soil layer over a long period of time.

[0045] [Correction of uneven settlement] Next, a process for correcting the unevenly settled structure 10 using the uneven settlement correction drain 100 (see FIG. 1) will be described. The construction method of the uneven settlement correction drain 100 may be either the fracturing injection method of the first construction method or the high pressure injection method of the second construction method.

[0046] As shown in Figures 3(A) and 3(B), an uneven settlement correction drain 100 is constructed immediately below and around the structure 10 (in this example, the right side of the structure 10) on the side of the ground G where the amount of settlement of the unevenly settled structure 10 is smaller (the right side in the figure). A water conduit 150 is constructed in the clayey soil layer 50.

[0047] In this example, a total of four uneven settlement correction drains 100 are constructed at intervals in the X and Y directions, but this is not limited to this. Also, in this example, as shown in Figure 8, the interval L1 between the drainage holes 120 is wider than the interval L2 between the water paths 150 in the vertical direction.

[0048] The interval L1 between the drainage holes 120 is the distance between the peripheries of the drainage holes 120 adjacent to each other on the left and right. Similarly, the interval L2 between the water paths 150 in the vertical direction is the distance between the peripheries of the water paths 150 adjacent to each other on the top and bottom.

[0049] Here, the peripheral surface of the drain hole 120 is uneven. Therefore, the interval L1 varies widely and cannot be measured accurately. In addition, the water path 150 is branched and not straight. Therefore, the interval L2 varies even more than the interval L1 and cannot be measured accurately.

[0050] However, as shown in Fig. 8, for example, the drainage holes 120 can be constructed at intervals of several meters to several tens of meters, and the water paths 150 can be constructed at intervals of 1 m or less, so that it can be said with certainty that the interval L1 is greater than the interval L2. Also, there is no problem with this level of accuracy in comparing the intervals L1 and L2.

[0051] As shown in Fig. 4(A), the pore water in the clayey soil layer 50 of the ground G on the side of the structure 10 where the amount of settlement is smaller is drained through the water path 150 and the drainage hole 120, promoting uneven settlement of the clayey soil layer 50 of the ground G on the side of the structure 10 where the amount of settlement is smaller. The arrows in the figure indicate the flow of the pore water.

[0052] Then, as shown in FIG. 4(B), when the amount of settlement of the structure 10 becomes uniform, the drainage is stopped, and the uneven settlement of the structure 10 is corrected.

[0053] In this example, the interstitial water is naturally drained by the load of the structure 10 and the ground G, but this is not limited to this, and the water may be forcibly drained using a suction pump or the like in order to shorten the time required to correct the uneven settlement.

[0054] The discharged viscous fluid M whose viscosity has decreased over time and the drained pore water of the clayey soil layer 50 may be disposed of in any manner. In this example, as shown in FIG. 7, a tubular member 30 such as a pipe or hose is installed at the upper end of the drainage hole 120 of the differential settlement correction drain 100, and the water is disposed of in an appropriate manner, such as by discharging the water into the sewer system.

[0055] [Effect] Next, the operation of this embodiment will be described.

[0056] The interstitial water is drained from the drainage holes 120 constructed vertically and the water paths 150 extending horizontally. This promotes localized drainage of the interstitial water in the clayey soil layer 50 on the side of the structure 10 where the amount of settlement is smaller, thereby promoting localized consolidation settlement of the clayey soil layer 50. Therefore, the uneven settlement occurring in the structure 10 can be corrected in a short period of time.

[0057] From another perspective, the drainage distance in the clayey soil layer 50 can be shortened compared to when only the drainage holes 120 are constructed. Alternatively, the differential settlement correction drain can be constructed in a shorter time than when only a large number of drainage holes 120 are constructed vertically to shorten the drainage distance in the clayey soil layer 50. Therefore, the differential settlement of the structure 10 can be corrected in a shorter time.

[0058] In addition, since the coarse granular material 160 is filled in the water path 150, the water path 150 is prevented from being blocked as the consolidation progresses. Therefore, a decrease in the drainage capacity due to the blocking of the water path 150 is prevented or suppressed.

[0059] (drainage distance) Next, it will be explained that by constructing vertical drainage holes 120 and horizontally extending water paths 150, the drainage distance can be made shorter than when only the same number of vertical drainage holes 120 are constructed. Note that the "drainage distance" is the distance from a certain point in the clayey soil layer 50 to the drainage boundary.

[0060] The drainage distance H1 in the case of only the drainage holes 120 is 1 / 2 the distance L1 between the drainage holes 120 shown in Fig. 8. In contrast, the drainage distance H2 in the case of constructing the water paths 150 extending in the horizontal direction is 1 / 2 the distance L2 between the upper and lower water paths 150 shown in Fig. 8. Therefore, by constructing the water paths 150 extending in the horizontal direction at intervals in the vertical direction in addition to the drainage holes 120 constructed in the vertical direction, the drainage distance is shortened.

[0061] (Relationship between drainage distance and consolidation settlement) Next, the principle that shortening the drainage distance shortens the time required for consolidation settlement will be explained.

[0062] The following equation (1) is the consolidation equation that describes the consolidation phenomenon of a clayey soil layer. e is the excess pore water pressure, and c v is the consolidation coefficient.

[0063]

number

[0064] The solution of the consolidation equation in [Equation 1] by the boundary condition and initial condition of excess pore water pressure is given as the following [Equation 2]. Here, H is the drainage distance and q is the surcharge load.

[0065]

number

[0066] The following equation (3) expresses the degree of compaction, U, which is an index showing the progress of compaction, and U(t)=ρ(t) / ρ fHere, ρ(t) is the amount of consolidation settlement at time t ([Equation 4]), and ρ f is the final consolidation settlement.

[0067]

number

[0068] The amount of consolidation settlement ρ(t) at time t is given by [Equation 4] using the excess pore water pressure ([Equation 2]). When consolidation is completely completed, that is, when "ρ = ρf", the degree of consolidation U is 100%. In the initial stage of consolidation, the degree of consolidation U is 0%.

[0069]

number

[0070] Then, when the time coefficient Tv is defined as in the following [Equation 5], the relationship between the degree of consolidation U and the time coefficient Tv is as shown in the graph of FIG. 9 from [Equation 3].

[0071]

number

[0072] 9, it can be seen that the shorter the drainage distance H, the larger the time coefficient Tv and the greater the degree of consolidation, and therefore the faster the consolidation progresses. In other words, if the drainage distance H is shortened, the consolidation time t required to reach the same degree of consolidation is shortened.

[0073] Note that Tv is inversely proportional to the square of the drainage distance H, that is, when the drainage distance H is halved, Tv becomes four times larger. Therefore, it is clear that the drainage distance H is effective in shortening the consolidation time t. In other words, in this example, since the drainage distance H2, which is 1 / 2 the interval L2 shown in Figure 8, is smaller than the drainage distance H1, which is 1 / 2 the interval L1, it is clear that the drainage time is significantly shortened.

[0074] <Second application example> Next, a second application example will be described in which the differential settlement correction drain 100 is used to correct the unevenly settled structure 12. Note that the same reference numerals are used for the same components as in the first application example, and duplicated descriptions will be omitted or simplified.

[0075] [Structures / ground] First, the structure 12 and the ground G will be described.

[0076] As shown in Fig. 5(A), the structure 12 of this application example has a pile foundation structure. The ground G on which the structure 12 is constructed has an upper clayey soil layer 60 below a surface layer not shown. Below this upper clayey soil layer 60 is a sandy soil layer 62. Below the sandy soil layer 62 is a lower clayey soil layer 64. The piles 14 of the structure 12 are embedded in the sandy soil layer 62. In other words, the structure 12 has a pile foundation structure with the sandy soil layer 62 as a supporting layer.

[0077] Figure 5 (B) shows a state in which the lower clayey soil layer 64 has settled due to consolidation during construction of the structure 12 or during its service period after completion, causing the sandy soil layer 62 to tilt and resulting in uneven settlement of the structure 12 with piles 14 embedded in the sandy soil layer 62.

[0078] [Correction of uneven settlement] Next, a process for correcting the unevenly settled structure 12 using the unevenly settled drain 100 will be described. The method for constructing the unevenly settled drain 100 may be either the fracturing injection method of the first construction method or the high pressure injection method of the second construction method.

[0079] As shown in Figure 6 (A), an uneven settlement correction drain 100 is constructed immediately below and around the structure 12 (the right side of the structure 12 in this example) on the side of the ground G where the uneven settlement of the structure 12 is smaller (the right side in the figure). The drainage hole 120 is constructed so as to reach the clayey soil layer 64 below. And a water conduit 150 is constructed in the clayey soil layer 64 below.

[0080] In this embodiment, as in the first application example, a total of four uneven settlement correction drains 100 are constructed at intervals in the X and Y directions, but this is not limited to this. Also in this embodiment, the interval L1 between the drainage holes 120 is larger than the interval L2 in the vertical direction of the water path 150 (see FIG. 8).

[0081] In this example, the vertical drainage hole 120 of the uneven settlement correction drain 100 on the left side in FIG. 6(A) is constructed at an angle to the vertical direction.

[0082] As shown in Figure 6 (A), the interstitial water in the clayey soil layer 64 below the ground G on the side of the structure 12 where the amount of subsidence is smaller is drained through the water path 150 and the drainage hole 120, promoting uneven settlement of the clayey soil layer 50 of the ground G on the side of the structure 12 where the amount of subsidence is smaller.

[0083] Then, as shown in FIG. 6(B), when the amount of settlement of the structure 12 becomes uniform, the drainage is stopped, and the uneven settlement of the structure 12 is corrected.

[0084] In this example, the interstitial water is naturally drained by the load of the structure 12 and the ground G, but this is not limited to this, and the water may be forcibly drained using a suction pump or the like in order to shorten the time required to correct the uneven settlement.

[0085] Also in this example, as shown in FIG. 7, a tubular member 30 such as a pipe or hose was installed at the upper end of the drainage hole 120 of the uneven settlement correction drain 100, and the water was discharged into the sewer or otherwise disposed of in an appropriate manner.

[0086] [Effect] Next, the operation of this embodiment will be described.

[0087] The interstitial water is drained from the drainage holes 120 constructed vertically and the water paths 150 extending horizontally. This promotes localized drainage of the interstitial water in the clayey soil layer 64 on the lower side of the structure 12 where the amount of settlement is smaller, and as a result, promotes localized consolidation settlement of the clayey soil layer 64. Therefore, the uneven settlement occurring in the structure 12 can be corrected in a short period of time.

[0088] From another perspective, the drainage distance in the clayey soil layer 50 can be made shorter than when only the drainage holes 120 are constructed. Alternatively, the differential settlement correction drain can be constructed in a shorter time than when only a large number of drainage holes 120 are constructed vertically to shorten the drainage distance in the clayey soil layer 50. Therefore, the differential settlement of the structure 12 can be corrected in a short time.

[0089] In addition, since the coarse granular material 160 is filled in the water path 150, the water path 150 is prevented from being blocked as the consolidation progresses. Therefore, a decrease in the drainage capacity due to the blocking of the water path 150 is prevented or suppressed.

[0090] <Other> The present invention is not limited to the above embodiment.

[0091] For example, in the above embodiment, the water path 150 is filled with the coarse granular material 160, but this is not limited to this. The water path 150 does not have to be filled with the coarse granular material 160.

[0092] In addition, for example, in the above embodiment, the water path 150 is constructed radially over 360° in a plan view (see FIG. 1(A)), but this is not limited to this. For example, as shown in FIG. 10, the water path 150 may be constructed radially over a range of approximately 180° in a plan view.

[0093] Also, for example, in the above first application example, the structure 10 is a spread foundation structure with the clayey soil layer 50 as a supporting layer, but the present invention is not limited to this. For example, a sandy soil layer may exist on the clayey soil layer 50, and the building may be a spread foundation structure with the sandy soil layer as a supporting layer. In this case, the water path 150 is constructed in the clayey soil layer 50 below the sandy soil layer.

[0094] In addition, for example, the structure 10 in the first application example is a spread foundation structure, and the structure 12 in the first application example is a pile foundation structure, but the present invention is not limited to these. For example, the present invention can be applied to structures with a base isolation structure and an intermediate isolation structure.

[0095] In addition, for example, in the above-mentioned first and second application examples, the vertical drainage holes 120 of the differential subsidence correction drain 100 are constructed both immediately below and around the structures 10, 12, but this is not limited to this. The vertical drainage holes 120 of the differential subsidence correction drain 100 may be constructed only either immediately below or around the structures 10, 12. Note that, when constructing the drainage holes 120 only around the structures 10, 12, it is desirable that the water path 150 is located immediately below the structures 10, 12.

[0096] Furthermore, the present invention can be embodied in various forms without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0097] 10 Structures 12 Structures 50 Clay layer 64 Clay layer 100 Drain for correcting uneven settlement 120 Drain hole 150 Waterway 160 Coarse grain material

Claims

1. A drainage hole is constructed vertically from the ground surface at least one of immediately below the structure and around the structure on the side of the structure where the amount of settlement of the structure is smaller due to the consolidation settlement of the clayey soil layer; A plurality of water paths extending radially from the drainage holes in the horizontal direction and constructed in the clayey soil layer at intervals in the vertical direction; A differential settlement correction drain equipped with a

2. The water path is filled with coarse granular material. The differential settlement correction drain according to claim 1.

3. constructing a drainage hole vertically from the ground surface at least one of immediately below the structure and around the structure on the side of the structure where the amount of settlement is smaller due to the consolidation settlement of the clayey soil layer; constructing a plurality of water paths extending radially from the drainage holes in the clayey soil layer at intervals in the vertical direction; Draining the pore water of the clayey soil layer through the drainage holes to promote consolidation settlement of the clayey soil layer on the side with a smaller amount of settlement; a step of stopping drainage of the pore water when the settlement amount of the structure is equalized; A method for correcting uneven settlement of a structure comprising:

4. The step of constructing the water path includes: A step of fracturing and injecting a self-decomposing viscous fluid mixed with a coarse-grained material into the clayey soil layer through the drainage hole; a step of discharging the viscous fluid whose viscosity has decreased due to a change over time from the drainage hole and leaving the coarse granular material in the water path; having The method for correcting uneven settlement of a structure according to claim 3.

5. The step of constructing the water path includes: A step of constructing a plurality of water paths extending radially from the drainage holes in the clayey soil layer at intervals in the vertical direction by a high-pressure jet mixing method; A step of injecting a self-decomposing viscous fluid mixed with a coarse granular material into the water path through the drainage hole; a step of discharging the viscous fluid whose viscosity has decreased due to a change over time from the drainage hole and leaving the coarse granular material in the water path; having The method for correcting uneven settlement of a structure according to claim 3.

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