JP5850529B2 - Underground continuous wall structure - Google Patents

Description

  The present invention relates to an underground continuous wall structure that reduces liquefaction damage below the ground surface.

  The ground liquefaction phenomenon occurs in a wide area in the event of a large earthquake or a huge earthquake. Elucidation of the mechanism of the liquefaction phenomenon and countermeasures are very difficult because it depends on the ground conditions and the scale of the earthquake. In buildings such as houses, the most scary thing about earthquakes is the magnitude of shaking rather than vibration, which causes damage to buildings. For this reason, building strong structures with improved structural performance, such as earthquake resistance, seismic control, and seismic isolation, is progressing. However, for shallow ground where small structures such as houses are constructed, earthquake countermeasures are hardly taken. In the planned construction sites such as houses, the ground strength is investigated and the ground is improved for the soft ground, but the countermeasures against liquefaction are almost impossible.

  When the planned construction site of an outdoor structure such as a small-scale private house is soft ground, a shallow ground improvement method that suppresses uneven settlement of the ground by hitting a ground stabilizer near the foundation construction part that is the soft ground It has been known. For example, in Japanese Patent Application Laid-Open No. 2004-60290, a stabilizer forming groove whose width and depth are adjusted by the strength of the ground in the vicinity of the foundation construction portion is set so that the cross section gradually increases from the groove bottom surface upward. After excavation, the soil was replaced with improved soil containing soil cement, and the soil replacement portion was rolled with a rammer to create a stabilizer with improved soil quality and soil strength and toughness. There is disclosed a solid foundation method with a stabilizer that integrates a stabilizer and a solid foundation. According to the construction method, since the stabilizer and the solid foundation are integrated, the soil surrounded by the stabilizer and the solid foundation portion becomes a rigid body and the rigidity of the solid foundation can be increased, and a load is applied from above. Even in such a case, the load can be received by the side of the stabilizer, and the influence of the building on the ground can be dispersed and reduced to improve the balance and the stability effect.

JP 2004-60290 A

  However, the conventional shallow ground improvement method improves the soft ground to a rigid ground that does not cause uneven settlement, and does not prevent liquefaction damage. Of course, in recent shallow ground improvement methods, it is not necessary to prevent soft subsidence from causing subsidence, and as a countermeasure against liquefaction caused by a large earthquake, it is also necessary to take measures against shallow ground. This is the current situation.

  Accordingly, an object of the present invention is to provide an underground continuous wall structure that improves the ground of a shallow ground that is a soft ground and reduces liquefaction damage.

  In such a situation, as a result of intensive studies, the present inventor has determined that at least the contiguous wall of the four sides forming the central chamber in the impermeable underground continuous wall structure constructed on the shallow ground. If two walls are provided with a communication pipe or a permeable layer, and the ground surface layer of the ground in the center is a permeable layer, the shallow ground that is a soft ground will be improved and the liquefaction damage will be reduced. As a result, the present invention has been completed.

  That is, the present invention is an impermeable underground continuous wall structure that is located below a foundation portion of an outdoor structure and is constructed on a shallow ground, and includes a continuous outer wall that forms an outer periphery, and the outer wall. The inner wall is divided into a plurality of chambers, and a continuous wall that forms a rectangular chamber is provided at the center, and at least two of the four continuous walls that form the central chamber face each other. The present invention provides a continuous underground wall structure characterized in that a communication pipe is provided on the wall and the ground surface layer of the ground in the center room is a water permeable layer.

Further, the present invention is an impermeable underground continuous wall structure which is located below a foundation portion of an outdoor structure and is constructed on a shallow ground, and includes a continuous outer wall forming an outer periphery, and the outer wall. It consists of an inner wall that divides the enclosed inside into a plurality of chambers, and a continuous wall that forms a rectangular chamber at the center is provided,
A second continuous wall surrounding the first continuous wall is further provided outside the continuous wall (first) forming the central chamber and inside the outer wall, and between the outer wall and the second continuous wall. A long communication pipe directly connecting the formed outer chamber and the central chamber is formed across the first continuous wall and the second continuous wall, and a water permeable layer is provided on the ground in the central chamber. An underground continuous wall structure is provided.

  Further, the present invention is an impermeable underground continuous wall structure which is located below a foundation portion of an outdoor structure and is constructed on a shallow ground, and includes a continuous outer wall forming an outer periphery, and the outer wall. The inner wall is divided into a plurality of chambers, and is provided with a continuous wall forming a rectangular chamber at the center. The upper end of the continuous wall forming the central rectangular chamber is higher than the upper end of the outer wall. It is an object of the present invention to provide an underground continuous wall structure characterized in that a water permeable layer is formed on an upper surface of a continuous wall which is in a lower position and forms the ground in the central chamber and the rectangular chamber in the center.

  ADVANTAGE OF THE INVENTION According to this invention, while improving the ground of the shallow ground which is a soft ground, liquefaction damage can be reduced.

It is a perspective view of the underground continuous wall structure in the 1st Embodiment of this invention. It is the schematic sectional drawing seen along the XX line of FIG. It is a top view of the underground continuous wall structure of FIG. It is a schematic sectional drawing of the underground continuous wall structure in the 2nd Embodiment of this invention. It is a top view of the underground continuous wall structure in the 3rd Embodiment of this invention. It is a top view of the underground continuous wall structure in the 4th Embodiment of this invention. It is a top view of the underground continuous wall structure in the 5th Embodiment of this invention. It is a schematic sectional drawing of the underground continuous wall structure of FIG. It is a top view of the underground continuous wall structure in the 6th Embodiment of this invention. It is a schematic sectional drawing of the underground continuous wall structure of FIG. It is a top view of the underground continuous wall structure in the 7th Embodiment of this invention. It is a schematic sectional drawing of the underground continuous wall structure of FIG. It is an exploded view of the pressure control valve provided in the pipe of the underground continuous wall structure of FIG. FIG. 14 is an assembly diagram of the pressure regulating valve of FIG. 13. It is a figure explaining the effect | action of the pressure regulating valve of FIG. It is a top view of the underground continuous wall structure in the 8th Embodiment of this invention. It is a modification of the underground continuous wall structure of FIG. It is a modification of the underground continuous wall structure of FIG. It is a figure which shows the modification of a water permeable layer. It is the figure seen along the YY line of FIG. It is a figure explaining the "center" in the planar view of the underground continuous wall structure of this invention.

  An underground continuous wall structure (hereinafter also referred to as “improved wall”) in the first embodiment of the present invention will be described with reference to FIGS. A symbol L in FIG. 1 indicates a longitudinal direction, and a symbol S indicates a short direction. Further, FIG. 2 depicts a base 50 for easy understanding. The underground continuous structure 10 includes a continuous outer wall 1 that forms an outer periphery, and an inner wall 2 that divides the inner side surrounded by the outer wall 1 into a plurality of chambers, and a cement-based solidification that forms a rectangular chamber at the center. It is an improved soil that is made by mixing materials. The partition shape in which the inner side surrounded by the outer wall 1 is partitioned by the inner wall 2 is not particularly limited, and examples thereof include a lattice shape and an indefinite shape having a rectangular chamber at the center. In the case of a lattice shape, the number of chambers partitioned in a lattice shape by vertical and horizontal walls is, for example, about 9 to 25. As an indefinite shape having a rectangular chamber (partition section) in the center, the one shown in FIG. Examples of the shape of the underground continuous structure 10 in plan view include vertically symmetrical, left-right symmetric and asymmetrical shapes. Among them, the vertically symmetrical and left-right symmetric shapes are preferable in that the ground is evenly restrained.

The center on the inner side surrounded by the outer wall 1 is the center in the front-rear direction and the left-right direction in a plan view when the shape surrounded by the outer wall is rectangular, and when the shape surrounded by the outer wall is asymmetric, the following method It is determined by taking one of the following. That is, as shown in FIG. 21A, in the asymmetric improved wall formed of ABCDEF, when the aAFE shape is smaller than the ABCbF shape, the aAFE shape is regarded as a recessed shape, and the recessed shape is ignored. Then, in the method of setting the center G of the aBCD shape as the center of the “center”, as shown in FIG. 21B, in the asymmetric improved wall formed of ABCDEF, the bAFE shape is larger than the ABaF shape. In the case of the area, the ABaF shape is regarded as a protruding shape, the protruding shape is ignored, and the center G of the EaCD shape is set as the center of the “center”, as shown in FIG. And the aDEF shape center g ₁ and the aDEF shape center g ₂ are determined, and the line connecting g ₁ and g ₂ is determined by area allocation. There is a method in which the center G is the center of the “center”. If none of the above applies, for example, the center of gravity of an outdoor structure that is a building may be the center of the “center”.

  The underground continuous structure 10 uses the outer wall 1 as a continuous wall, and the inner wall 2 partitions the inner wall 2 to constrain and integrate the ground, and to uniformly transmit the load of the outdoor structure to the ground. The structure foundation and ground strength of the building will be improved, and the stability of the entire outdoor structure will increase. In addition, it is possible to suppress shear fracture and movement of the ground during an earthquake.

The underground continuous structure 10 is constructed on the shallow ground 51 below the foundation 50 of the outdoor structure. The outdoor structure may be a small house, a store, a building such as a factory, a garden, a private road, or a parking lot. A small house, a small building as defined in the "small-scale building foundation design guidelines (Architectural Institute of Japan)", three floors below, building height 13m below, eaves height 9m or less and a total area of 500m ² A building that satisfies the following conditions. The base of the outdoor structure is, for example, a solid foundation in the case of a small house, and in the case of a large area outdoor structure such as a store, factory, garden, driveway or parking lot, garden, driveway or parking lot, For example, a surface layer including a gravel layer and an asphalt pavement layer. FIG. 2 shows a case of a small-scale house, in which a solid foundation 50 is formed on the underground continuous structure 10. That is, the upper surface of the underground continuous structure 10 is covered with the foundation 50, and preferably the underground continuous structure 10 and the foundation 50 are integrated. In the present invention, the underground continuous structure has a maximum height of 2.0 m, generally 0.3 to 1.8 m.

  In the present invention, the communication pipes are installed on at least two walls facing each other among the continuous walls having four sides forming the central chamber. The communication pipe allows water and earth and sand to pass through together. For example, a cylindrical pipe that is equal to or slightly longer than the thickness of the inner wall 2 can be used. The underground continuous structure 10 in FIG. 1 is configured by two vertical walls 21a and 21b and two horizontal walls 22a and 22b so that the inside of the outer wall 1 is divided into nine chambers. Among the walls corresponding to the four sides forming the chamber, the lateral walls 22a and 22b extending in the lateral direction are formed. Moreover, the communication pipe 3 is formed in the upper part of the horizontal walls 22a and 22b. The upper part means above the center in the height direction.

  In the present invention, a water permeable layer is provided on the ground in a central room. That is, in the underground continuous structure 10, the water permeable layer 4 is provided on the ground 51 in the central chamber 15. Examples of the water permeable layer 4 include a crushed stone layer and a chestnut layer. The water permeable layer 4 has water permeability higher than that of the ground in the other chambers 11 to 14 and 16 to 19 other than the central chamber. Moreover, the water-permeable layer 4 has a porosity higher than the porosity of the ground in other chambers 11-14, 16-19 other than a center chamber. In the present invention, the water permeable layer 4 is formed in the center chamber 15 as a whole in plan view, and the maximum height is three times the wall depth (height) of the improved wall in the depth direction. , Preferably 2 times, specifically 4 m at maximum, preferably 3 m at maximum, particularly preferably 2.5 m at maximum. The cross-sectional shape of the water permeable layer may be a shape (inverted trapezoidal shape) that is slightly tapered in the depth direction in addition to the rectangular cross section. In FIG. 2, the water permeable layer 4 is formed entirely in the central chamber 15 in a plan view, and is approximately half the height of the wall forming the central chamber 15 in the depth direction. And the installation position in the depth direction of the communication pipe 3 is installed in the water permeable layer 4. FIG. 17 is a modification of the underground continuous structure 10 in FIG. 2 and is a cross-sectional view at the center in the short direction. 17 differs from FIG. 2 in the shape of the water permeable layer 4. That is, in the underground continuous structure 10H in FIG. 17, the water permeable layer 4 has a shape that is deeper than the wall depth H of the improved wall and is slightly tapered in the depth direction (inverted trapezoidal shape). . Such a water permeable layer can be easily formed by rolling with a rammer or the like, then excavating with a small excavating machine such as Yumbo, and laying crushed stone. According to the underground continuous structure 10H, the volume of the water permeable layer 4 becomes large, and the allowable amount for storing the sand containing pore water pressure and rising water increases.

  Liquefaction sand flow caused by a large earthquake does not usually occur in the entire area of the improved wall, but occurs in a part of it and appears as rising water containing earth and sand. For example, a sand flow generated in the chamber 12 (wife side) is guided to the adjacent central chamber 15 through the communication pipe 3 as indicated by an arrow, and diffuses to the opposite chamber 18 via a time difference. And since the three chambers 12, 15, and 18 which are the center part of a transversal direction are connected by the communication pipe 3, a sand flow flows in these three chambers. Since the water permeable layer 4 is formed in the central chamber 15, the sand flow is likely to accumulate in the water permeable layer 4. For this reason, the rising pressure by the sand flow is applied evenly to the central chamber 15 or the central portion in the short direction, the horizontal stability of the outdoor structure is maintained, and uneven settlement can be suppressed. This effect is the same for the sand flow generated in the chamber region of the chamber 15 or 18 which is the central portion in the short direction. In addition, since the water permeable layer 4 is a crushed stone or a chestnut stone industry, the earth proof strength is ensured. In addition, when the sand flow flows in the chambers 11, 14, 17, 13, 16, 19 (girder side) other than the central portion in the short direction, the rise of the sand flow is restrained to the limit without escaping. . Thereby, the spreading | diffusion of the liquefaction damage range can be prevented. Therefore, the underground continuous structure 10 can reduce the damage caused by the liquefaction phenomenon, if not completely.

  Next, a method for creating the underground continuous structure 10 will be described. The underground continuous structure 10 is formed by a known method except for the installation of the communication pipe and the water permeable layer. That is, a groove having the shape of FIG. 1 is formed in the ground in the region (soft ground) where the underground continuous structure 10 is created. Next, the improved soil obtained by stirring and mixing the cement-based solidified material in the groove is backfilled. After that, the improved soil part is rolled with a rammer or the like to construct an improved wall made of improved soil that has soil strength and toughness. Integrate. The communication pipe 3 is constructed in advance at a predetermined position when a groove is formed in the ground, and then the improved soil obtained by stirring and mixing the cement-based solidifying material is backfilled, so that the communication pipe 3 is formed on the outer wall 1. You may make it do. Moreover, after rolling with a rammer or the like, the installation location may be scraped off and then attached to the installation location. Further, when the water permeable layer 4 forms a groove in the ground, a crushed stone or a chestnut stone industry is preliminarily formed in a predetermined position, and then, an improved soil that is stirred and mixed with a cement-based solidifying material is poured into the central chamber 15 Alternatively, the water permeable layer 4 may be formed. Further, after rolling with a rammer or the like, the installation location may be excavated, and then the installation location may be subjected to crushed stone or chestnut stone.

  Next, the underground continuous wall structure in the 2nd Embodiment of this invention is demonstrated with reference to FIG. In the underground continuous structure 10A in FIG. 4, the same components as those in the underground continuous wall structure 10 in FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described. That is, the underground continuous structure 10A in FIG. 4 differs from the underground continuous wall structure 10 in FIG. 1 in that the lower ends of the lateral walls 22a and 22b that form the inner wall 2 and extend in the short direction are the lower ends of the outer wall 1. It is the point which is in the H dimension and the upper position. That is, a step is provided at the bottom of the improved wall. Thereby, for example, the sand flow (arrow x) generated in the chamber 12 (wife side) is guided to the adjacent central chamber 15 through the communication pipe 3, but on the other hand, in the central chamber in the short direction. In addition, at the lower end portion without the lateral walls 22a, 22b, the fluid can flow in the direction of the arrow y. For this reason, it becomes possible to delay the overflow phenomenon in the extreme state where the sand flow flows out beyond the outer wall 1. Therefore, the underground continuous structure 10 </ b> A can further reduce damage caused by the liquefaction phenomenon than the underground continuous structure 10. The step of the bottom of the improved wall is not limited to the lower ends of the horizontal walls 22a and 22b as shown in FIG. 4, and may be formed at the lower ends of the vertical walls 21a and 21b, and all the inner walls 2 are formed. It may be formed on the wall.

  Next, the underground continuous wall structure in the 3rd Embodiment of this invention is demonstrated with reference to FIG. In the underground continuous structure 10B in FIG. 5, the same components as those in the underground continuous wall structure 10 in FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described. That is, the underground continuous structure 10B in FIG. 5 is different from the underground continuous wall structure 10 in FIG. In other words, the underground continuous structure 10 </ b> B is configured such that the communication pipe 3 is installed on all the four side walls forming the central chamber 15. Thereby, the sand flow generated in any one of the central chambers 12, 15, 18 in the short direction and the central chambers 14, 15, 16 in the longitudinal direction is caused to flow in the central chamber 15 or in the short direction and the longitudinal direction. Compared to the underground continuous wall structure 10, the horizontal stability of the outdoor structure is more easily maintained and the uneven settlement can be suppressed. Even in the underground continuous structure 10B, a step may be provided on the bottom of the improved wall.

  In the underground continuous structure 10B, the installation position of the communication pipe 3 is not limited to the installation position of FIG. 5, and may be formed on the vertical wall or the horizontal wall of the inner wall forming each chamber. In this case, even if the sand flow caused by liquefaction occurs in any chamber, the communication pipe 3 is connected to the whole, so that the rising pressure due to the sand flow can be averaged in all of the ground surrounded by the improved wall.

  Next, the underground continuous wall structure in the 4th Embodiment of this invention is demonstrated with reference to FIG. In the underground continuous structure 10C in FIG. 6, the same components as those in the underground continuous wall structure 10 in FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described. That is, the underground continuous structure 10C in FIG. 6 is different from the underground continuous wall structure 10 in FIG. 1 in the positions where the water permeable layer 4 and the communication pipe 3 are formed. That is, the underground continuous structure 10C is formed by forming the water permeable layer 4 on the ground of all the rooms divided by the inner wall 2, and installing the communication pipe 3a at the intersection of the vertical wall and the horizontal wall. Thereby, the sand flow generated in any one of the nine chambers 11 to 19 is equally applied to all the chambers 11 to 19, and compared to the underground continuous wall structures 10, 10A, and 10B. The horizontal stability of the object is more easily maintained, and the uneven settlement can be suppressed. Even in the underground continuous structure 10C, a step may be provided on the bottom of the improved wall. The communication pipe 3a may be a commercially available four-forked pipe that is open at four sides and communicates with each other. In the underground continuous structure 10C, the thickness of the water permeable layer 4 may be the same, or only the water permeable layer 4 formed in the central chamber may be thicker than the water permeable layers formed in other chambers. In this case, the rising pressure is easily applied to the central water permeable layer 4, and the horizontal stability of the outdoor structure is more easily maintained.

  FIG. 18 is a modified example of the underground continuous structure 10C in FIG. 6, and is a cross-sectional view at the center in the lateral direction. 18 differs from FIG. 6 in the shape of the water permeable layer 4. That is, in the underground continuous structure 10I of FIG. 18, the water permeable layer 4 has a depth (inverted trapezoidal shape) that is deeper than the wall depth H of the improved wall and is slightly tapered in the depth direction. . Such a water permeable layer can be easily formed by rolling with a rammer or the like, then excavating with a small excavating machine such as Yumbo, and laying crushed stone. According to the underground continuous structure 10 </ b> C, the volume of the water permeable layer 4 is increased, and the allowable amount for storing the sand is increased.

  Next, the underground continuous wall structure in the 5th Embodiment of this invention is demonstrated with reference to FIG.7 and FIG.8. In the underground continuous structure 10D of FIGS. 7 and 8, the same components as those of the underground continuous wall structure 10 of FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described. . That is, the underground continuous structure 10D in FIGS. 7 and 8 is different from the underground continuous wall structure 10 in FIG. 1 in the division shape of the inner wall 2, the formation position of the water permeable layer 4 and the communication pipe 3. That is, the underground continuous structure 10D is provided with a second continuous wall 23b that surrounds the first continuous wall 23a on the outside of the first continuous wall 23a that forms the central chamber 15 and on the inside of the outer wall 1. A long communication pipe 3b that directly connects the outer chamber 11d formed between the first continuous wall 23b and the central chamber 15 is formed across the first continuous wall 23a and the second continuous wall 23b. The permeable layer 4 is provided on the ground in the chamber 15, the permeable layer 4 is formed on the ground in the central chamber 15, and the communication pipe 3 is formed on the wall extending in the longitudinal direction of the first continuous wall 23a. The long communication pipe 3b is the same except that the long communication pipe 3b is longer than the communication pipe 3.

  According to the underground continuous wall structure 10D, for example, the sand flow generated in the outer chamber (outer ring groove) 11d is guided to the central chamber 15 through the long communication pipe 3b as indicated by an arrow. Since the water permeable layer 4 is formed in the central chamber 15, the sand blast easily accumulates in the water permeable layer 4. For this reason, the rising pressure by the sand sand is uniformly applied to the central chamber 15, the horizontal stability of the outdoor structure is maintained, and uneven settlement can be suppressed. Further, for example, the sand flow generated in the chamber (inner ring groove) 12d between the first continuous wall 23a and the second continuous wall 23b is guided to the central chamber 15 through the communication pipe 3 as indicated by an arrow. The Since the water permeable layer 4 is formed in the central chamber 15, similarly, sand blast containing pore water pressure and rising water easily accumulates in the water permeable layer 4. For this reason, the rising pressure by the sand sand is uniformly applied to the central chamber 15, the horizontal stability of the outdoor structure is maintained, and uneven settlement can be suppressed. As described above, in the underground continuous wall structure 10 </ b> D, the rising pressure due to the sand sand is applied to the central chamber 15 evenly with respect to the sand sand flow generated at any location in the improved wall.

  In addition, the division | segmentation shape in particular of the inner wall 2 in the underground continuous wall structure 10D is not restrict | limited, The 3rd continuous wall 23b which further surrounds the 2nd continuous wall 23b on the outer side of the 2nd continuous wall 23b and the inner side of the outer wall 1 May be provided. In this case, even if the second long communication pipe that directly connects the outer chamber formed between the outer wall 1 and the third continuous wall and the central chamber 15 is formed across the first continuous wall 23a and the third continuous wall. Good. In the underground continuous structure 10D, a step may be provided on the bottom of the improved wall. Further, a water permeable layer may be formed in the ground 51 of the chamber (inner ring groove) 12d between the first continuous wall 23a and the second continuous wall 23b, and the inner ring groove 12d and the second continuous wall 23b and the outer wall 1 may be formed. A water permeable layer may be formed on any ground 51 in the chamber (outer ring groove) 11d between the two.

  In the underground continuous wall structure 10D, the communication pipe 3 formed on the first continuous wall 23a can be omitted. In this case, when a sand flow occurs in the chamber 12d formed between the first continuous wall 23a and the second continuous wall 23b, the rise of the sand is restrained to the limit without escaping. Thereby, the spreading | diffusion of the liquefaction damage range can be prevented. Further, in the underground continuous wall structure 10D, the height of the improved wall may not be the same between the outer wall and the inner wall as shown in FIG. 8, and the lower ends of the first continuous wall 23a and the second continuous wall 23b are The lower end of the outer wall 1 may be located above the lower end, the lower end of the second continuous wall 23b is located above the lower end of the outer wall 1, and the lower end of the first continuous wall 23a is the second continuous wall 23b. It may be in a position above the lower end of. As a result, similarly to the second embodiment, it is possible to delay the overflow phenomenon in the extreme state where the sand flow flows out of the outer wall 1 to the outside.

  Next, the underground continuous wall structure in the 6th Embodiment of this invention is demonstrated with reference to FIG.9 and FIG.10. In the underground continuous structure 10E of FIGS. 9 and 10, the same components as those of the underground continuous wall structure 10A of FIG. 4 are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described. . That is, the underground continuous structure 10E in FIGS. 9 and 10 is different from the underground continuous wall structure 10A in FIG. 4 in that the wall structure forming the central chamber, the installation position of the permeable layer 4 and the communication pipe 3 are the same. It is the presence or absence. In the underground continuous structure 10E, the upper end of the continuous wall forming the central rectangular chamber 15 is located below the upper end of the outer wall, and the upper part of the continuous wall forming the central chamber and the central chamber is located above the upper end of the outer wall. The water permeable layer 4 is formed, and the installation of the communication pipe 3 is omitted. That is, since the underground continuous structure 10E has the permeable layer 4 at the upper part of the continuous wall forming the central chamber, the area ratio responsible for the central concentration of the sand flow becomes high, and the outdoor structure is less likely to rise, Stabilization can be achieved. Further, the installation of the communication pipe 3 can be omitted. In the underground continuous structure 10E, the height of the improved wall is not limited to the structure as shown in FIG. 10, and for example, the outer wall 1 and the inner walls 22a and 22b may be the same.

  Next, the underground continuous wall structure in the 7th Embodiment of this invention is demonstrated with reference to FIG.11 and FIG.12. In the underground continuous structure 10F of FIGS. 11 and 12, the same components as those of the underground continuous wall structure 10 of FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described. . That is, the underground continuous structure 10F of FIGS. 11 and 12 is different from the underground continuous wall structure 10 of FIG. 1 in that one end 51 faces the inside of the central chamber 15 and the other end 52 faces the base 50. Is that the pipe 5 is provided so as to be located outside the base portion 50, and the water permeable filter 6 is installed in the pipe 5. In addition, the pipe 5 is arrange | positioned in the base part 50, and what is necessary is just to penetrate the inside of the wall 55 of the base part 50 as needed. In addition, it is preferable that the pipe 5 is installed in two or more places, preferably 2 to 6 places, and symmetrically if necessary, in that a large amount of rising water can be discharged to the outside. .

  The water permeable filter 3 allows water to pass therethrough and does not pass earth and sand, and examples thereof include a pipe filter. The pipe filter is formed by fitting a mesh filter or a water-permeable mat into the inside or end face of the pipe. As these mesh filters and water-permeable mats, those commercially available as clogging prevention devices for drain pipes can be used.

  Although the underground continuous structures 10 to 10E can reduce damage caused by a liquefaction phenomenon caused by a large earthquake or a huge earthquake, they are not perfect. However, the underground continuous structure 10F can prevent the damage caused by the liquefaction phenomenon almost in advance because the sand flow collected in the central catchment can be guided to the outside only by the pipe 5 through the permeable filter 6. it can. The other end 52 of the pipe 5 may be piped so as to flow into sewage, for example.

  A pressure regulating valve 7 can be installed in the pipe 5 of the underground continuous structure 10F. As shown in FIG. 13, the pressure regulating valve 7 includes a sphere support 72 and a sphere 722. The sphere support 72 is fitted into the end of a pipe, for example, and is formed by suspending a sphere support main body 721 that is an inverted trapezoidal thin plate having an opening 724 at the center in a short tubular pipe. The spherical body supporting body 721 may be made of the same material as the pipe 5 or a different material. The sphere 722 closes the opening 724 when inserted into the sphere support 72, and floats due to the rising pressure generated in the pipe 5 to form a gap between the openings 724. The sphere 722 is made of expanded polystyrene, resin, metal, or a composite thereof. The weight of the sphere 722 may be determined as appropriate. If the weight of the sphere 722 is too light, it will float at the rising pressure generated in the pipe 5 due to fluctuations in air temperature during normal times, so that bad odors and the like are generated. Also, if it is too heavy, it will not be possible to escape groundwater from the sand during an earthquake. A protective net 723 that suppresses the upward movement of the sphere 722 may be attached to the top surface of the sphere support portion 72.

  The pressure regulating valve 7 is normally in the state shown in FIG. That is, the sphere 722 is placed on the opening 724 of the sphere support 72 and closes the opening 724. Accordingly, during normal times, bad odors and the like from the pipe 5 are prevented, and underground moisture is prevented from rising below the floor. On the other hand, when a sand flow due to a liquefaction phenomenon occurs during an earthquake, the sphere 722 is pushed up by the rising pressure, a gap is generated between the sphere support main body 721 and the sphere 722, and the ground sand water is released from this gap. (FIG. 15).

  Next, the underground continuous wall structure in the 8th Embodiment of this invention is demonstrated with reference to FIG. In the underground continuous structure 10G in FIG. 16, the same components as those in the underground continuous wall structure 10E in FIGS. 9 and 10 are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described. . That is, the underground continuous structure 10G in FIG. 16 is different from the underground continuous wall structure 10E in FIGS. 9 and 10 in the divided shape of the inner wall 2. That is, the inner wall 2 of the underground continuous wall structure 10G is formed such that a wall 213 having a substantially similar shape smaller than the shape of the outer wall 1 is formed in the central portion with respect to the rectangular outer wall 1, and a corner portion of the wall 213 and the outer wall are formed. A radial wall 214 connecting the corners (inner corners) of one is further formed. In the underground continuous wall structure 10G, the sand flow generated in a part of the improved wall is guided to the corresponding chamber, and when it reaches near the ground surface, it passes through the permeable layer 4 and concentrates in the central chamber 215. To gather. Therefore, there exists an effect similar to the underground continuous wall structure 10E.

  In the present invention, the water permeable layer is not limited to the above-described embodiment, and various modifications may be adopted, for example, water permeable layers 4a to 4d as shown in FIG. That is, the water permeable layer 4a is formed without being in contact with the inner wall 2, and is smaller than the size of the chamber 11 partitioned by the inner wall 2 in a plan view, and has a rectangular cross section and larger than the wall height H. Has a height of The water permeable layer 4b is formed in two places in the chamber 12 without contacting the inner wall 2, and is smaller than the size of the chamber 11 partitioned by the inner wall 2 in a plan view, and is slightly tapered in the depth direction. It has a height slightly higher than the wall height H. The water permeable layer 4c is formed such that two of the four sides are in contact with a wall extending in the longitudinal direction of the inner wall 2 and the other two sides are not in contact with the inner wall. It is smaller than 11 and has a predetermined height. The water permeable layer 4d is formed so that two of the four sides are in contact with a wall extending in the short direction of the inner wall 2 and the other two sides are not in contact with the inner wall, and have a long shape in plan view. Yes. The height (depth) of the water permeable layers 4a to 4d is appropriately determined. Even with such permeable layers 4a to 4d, the same effect as the permeable layer 4 of the underground continuous wall structures 10H and 10I can be obtained, the flow of water flow can be changed, the water pressure can be differentiated, and the sand flow It is easy to obtain an effect of attenuating. In the case of the water permeable layers 4a to 4d, the communication pipe 3 does not need to be directly connected to the water permeable layers 4a to 4d. Even if the communication pipe 3 is not directly connected to the water permeable layers 4a to 4d, the sand flow generated by liquefaction flows through the communication pipe 3 into the indoor ground and flows into the water permeable layers 4a to 4d. In addition, the planar view shape and cross-sectional shape of water-permeable layers 4a-4d are not limited to the thing of FIG.19 and FIG.20, A fixed shape or indefinite shape other than the above may be sufficient. In addition, it is only necessary to determine which of the above-described underground continuous structures 10 to 10I is to be adopted based on the survey results of the ground.

  In the present invention, the method of dividing the inside of the outer wall into a plurality of chambers by the inner wall is not limited to the dividing method in the above embodiment, and various divided forms can be adopted. Moreover, the installation position and the installation number of the communication pipes are not limited to those in the above embodiment, and various installation positions and installation numbers can be adopted. Moreover, although the said embodiment is a case where a base part is a solid foundation and an outdoor structure is a small house, it is not limited to these, For example, an outdoor structure is a building other than a small house Applicable to gardens, driveways or parking lots. In this case, the foundation may be a surface layer including an gravel layer or an asphalt pavement layer, for example. As a method for constructing the foundation on the underground continuous structures 10 to 10I, a known method can be applied.

  In addition, when the outdoor structure has a large area such as a store, a factory, a private road, a garden, or a parking lot, as a method of partitioning the inside of the improved wall with the inner wall 2, there are a large number of tens to hundreds of rooms in a lattice shape. , A multiple arrangement method in which each of the underground continuous structures 10, 10 </ b> A to 10 </ b> I is set as one unit, a plurality of the same units are arranged side by side, or a plurality of mixed arrangements in which the same units and different units are combined are arranged. The method etc. are mentioned. When the outdoor structure has a large area, the number of rooms that divide the improved wall by the inner wall 2 is naturally larger than that of a small-scale house.

  ADVANTAGE OF THE INVENTION According to this invention, the sand-sand phenomenon which generate | occur | produced in a part in an improvement wall can be collected in the whole inside of the permeable layer of a center ground, or an improvement wall through a communicating pipe or a permeable layer. In particular, since the load of the outdoor structure is heavy at the central portion (center of gravity), if the sand flow is collected in the water permeable layer of the central portion, the stability for maintaining the level is improved. The present invention is a measure against uncertain elements such as the occurrence location, occurrence time, size, etc. in liquefaction, but during normal times, it contributes to further ground safety as a ground improvement wall, and during normal earthquake disasters It is possible to prevent damage and reduce damage to liquid phenomena that exceed expectations. Therefore, it can be the most effective means for earthquake countermeasures.

DESCRIPTION OF SYMBOLS 1 Outer wall 2 Inner wall 3, 3a Communication pipe 4, 4a-4d Permeable layer 10-10G Underground continuous wall structure 50 Solid foundation

Claims (15)

An impervious underground continuous wall structure that is located below the foundation of an outdoor structure and is constructed on a shallow ground, and a continuous outer wall that forms an outer periphery, and a plurality of inner sides surrounded by the outer wall It consists of an inner wall that is divided into chambers, and has a continuous wall that forms a rectangular chamber in the center,
A continuous underground wall characterized in that a communication pipe is provided on at least two walls facing each other among the four continuous walls forming the central chamber, and a water permeable layer is provided on the ground in the central chamber. Structure.   The underground continuous wall structure according to claim 1, wherein the water permeable layer is a crushed stone layer or a chestnut layer.   The underground continuous wall structure according to claim 1 or 2, wherein a communication pipe is provided on each of the four walls forming the central chamber.   The underground continuous wall structure according to any one of claims 1 to 3, wherein the inner wall divides the inner side surrounded by the outer wall into a lattice shape.   The underground continuous wall structure according to claim 4, wherein a communication pipe is provided on each of the walls forming the chambers divided in a lattice shape. And the inside of the outer wall outside the continuous wall which forms the center of the chamber (first), according to claim 1 further characterized in that a second continuous wall surrounding the continuous wall of the first Underground continuous wall structure. An impervious underground continuous wall structure that is located below the foundation of an outdoor structure and is constructed on a shallow ground, and a continuous outer wall that forms an outer periphery, and a plurality of inner sides surrounded by the outer wall It consists of an inner wall that is divided into chambers, and has a continuous wall that forms a rectangular chamber in the center,
A second continuous wall that further surrounds the first continuous wall is provided outside and inside the continuous wall (first) forming the central chamber, and between the outer wall and the second continuous wall. A long communication pipe that directly connects the outer chamber and the central chamber formed over the first continuous wall and the second continuous wall, and a permeable layer is provided on the ground in the central chamber. An underground continuous wall structure.   The underground continuous wall structure according to claim 7, wherein a communication pipe is provided on at least two walls facing each other among the four continuous walls forming the central chamber.   9. The pipe according to claim 1, wherein a pipe is provided on the foundation so that one end faces the central chamber and the other end is located outside the foundation, and a water permeable filter is installed in the pipe. The underground continuous wall structure according to any one of the above.   An impervious underground continuous wall structure that is located below the foundation of an outdoor structure and is constructed on a shallow ground, and a continuous outer wall that forms an outer periphery, and a plurality of inner sides surrounded by the outer wall A continuous wall that forms a rectangular chamber at the center, and the upper end of the continuous wall that forms the central rectangular chamber is located below the upper end of the outer wall, An underground continuous wall structure characterized in that a water permeable layer is formed on an upper portion of a continuous wall forming a ground in a central chamber and a rectangular chamber in the center.   The underground continuous wall structure according to any one of claims 4 to 10, wherein a lower end of a longitudinally extending wall forming the inner wall is located above a lower end of the outer wall.   The underground continuous wall structure according to any one of claims 4 to 10, wherein a lower end of a wall extending in a short direction forming the inner wall is located above a lower end of the outer wall.   The underground continuous wall structure according to any one of claims 1 to 12, wherein the underground continuous wall structure has a maximum height of 2.0 m. 該屋outer structures, buildings, underground continuous wall structure according to any one of claims 1 to 13, garden EMMA other is characterized by a parking lot.   The underground continuous wall structure according to claim 14, wherein the foundation is a solid foundation when the outdoor structure is a building.

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