JP2011241605A - Self-weight-settling caisson construction method and underground structure constructed by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively, stably and inexpensively settle a caisson regardless of soil property in constructing an underground structure where a skeleton structure of a caisson is constructed above the ground and settled by a self weight as inner bottom surface of the caisson is excavated.SOLUTION: A skeleton caisson is provided with, at a bottom thereof, a leading wedge having a shape of an inverted triangle made of at least partially a metal. The leading wedge is configured so that: an angle of a sharp tip thereof as well as the angle between an outer surface of a rising portion and a vertical line are prescribed; an inner rising portion has a bended portion inwardly extending with the angle perpendicular to the vertical line; and at least the outer and inner rising portions as well as the bended portion are made of the metal. Also, a concrete part of the caisson and the concrete part inside the leading wedge are integrated.

Description

In the present invention, a caisson (surrounding wall) for underground structures such as a basement and an underground water tank constructed on the ground is excavated on the ground surrounded by the caisson (surrounding wall) for underground structures, and is submerged under its own weight. It relates to the construction method and structure of the self-subsidence caisson for underground structures.

Conventionally, there is a so-called submersible construction method for constructing an underground structure consisting of a basement, an underground water tank, etc. in the basement. The submersible construction method is a method in which the caisson (surrounding wall) for underground structures built on the ground is submerged in the underground. The construction method involves submerging the underground structure in water and the inside surrounded by the caisson for the underground structure (surrounding wall). There is a method in which the caisson (surrounding wall) for underground structures is gradually submerged to the underground by its own weight while excavating the ground. The latter method is performed by an open type of caisson housing structure (peripheral frame shape having no bottom on the inside) in which a leading blade is provided at the lower part.

Many open-type caissons are provided with a caisson (surrounding wall) for an underground structure, and then a so-called submersible construction method in which the caisson is sunk underground. For this reason, the basement of an underground structure is constructed after the caisson (surrounding wall) for underground structures is sunk in the basement. In the construction where an open caisson is submerged by the submerged method, the caisson is produced on the ground. There are various advantages such as the burden of work is greatly reduced, the period is shortened, and the cost is reduced.

For example, in Patent Document 1, “The construction method of an underground structure according to the present invention is to place concrete on a concrete formwork on the ground surface to construct a concrete peripheral wall, and then remove the concrete formwork from the concrete peripheral wall. The excavation of the ground in the inner space of the concrete peripheral wall causes the concrete peripheral wall to sink, and the concrete peripheral wall without the concrete formwork sinks, so that the concrete peripheral wall is easy to handle. "
JP 2001-323435 A

However, the method of Patent Document 1 has a disadvantage in order to stably sink the caisson with its own weight. For example, when the ground is hard, for example, the case where it is soft or the like is not sufficiently considered. Further, when the caisson is sunk, there is a drawback that sufficient consideration has not been given to the possibility that the caisson itself may tilt due to friction with the ground wall. In addition, since there is no resistance surface at the time of sinking, oversinking cannot be stopped, and there is also a problem that it is difficult to adjust the inclination level of the caisson because there is no place for installing the jack base. Moreover, when installing the lower part of the caisson at the installation location, a jig or the like is required, which makes it difficult and requires a long construction period. There was a problem in removing the jig and the mold because the caisson's entire weight was applied to the corresponding next tool and the mold. The problem to be solved by the present invention is to settle the caisson to a predetermined position by eliminating the unequal settlement of the caisson by stably sinking the caisson with its own weight despite being inexpensive and efficient. It is also possible to deal with the type of ground and to solve the problem that the settlement of the caisson is not stable due to the ground. In addition, it prevents oversinking, eliminates the difficulty of adjusting the tilt level by providing a jack base installation location, solves the difficulty of installation of the lower caisson, and eliminates the need for special jigs. It is to make it easier.

In order to solve the above-mentioned problems, the present inventors have conducted intensive research and adopted the following method. That is, in the caisson where the outer wall of the basement is constructed on the ground and sinks under its own weight, at least a part is made of metal at the lower end portion of the caisson, and the outer frame and the inner frame are joined to the upper and outer formwork panels of the caisson. An inverted triangular hollow leading blade having an opening communicating with the space between them is provided. And, the leading edge rises outward from the pointed portion of the lower part of the inverted triangle of the leading blade section, and the upper end is formed to the portion extending to the intersection where it rises through the lower end of the outer form panel of the caisson and perpendicular to the vertical line. The portion that rises inward from the pointed portion of the lower portion of the inverted triangular portion of the reverse leading blade and extends inward at a predetermined position at a predetermined position may be made of at least metal. Of course, other parts of the leading blade may be made of metal as necessary.

And by filling concrete milk simultaneously between the hollow part of the leading blade below the caisson and the outer and inner formwork panels of the caisson, the concrete is continuous from the leading blade hollow part to the outer and inner formwork panels of the caisson. A section should be provided.
The upper end of the inverted triangular portion rises outward from the pointed portion, and the upper end is formed at the lower end of the outer formwork panel of the caisson, the lower end of the caisson concrete part from which the outer formwork panel of the caisson is removed, or the surface of the concrete. What is necessary is just to make it into predetermined length from the surface lower end part of a protective layer.

In the caisson, a special waterproof measure such as water-expandable resin is placed on this part when it is submerged to a predetermined part by integrating the wall part which is a concrete part of the caisson and the hollow part of the leading blade. Since there is no need to carry out the process, the cost is low and the construction period is advantageous. In addition, the strength has been lowered conventionally due to the entry of foreign substances such as water-expandable resin, but the structure of the present invention also eliminates the problem of strength degradation. In addition, the portion that rises inward from the pointed portion of the lower portion of the inverted triangular portion of the leading blade and extends inward by a line perpendicular to the vertical line at a predetermined position may be a jack base receiving surface when leveling horizontally. This enables accurate frame assembly. In addition, when caisson sinks under its own weight, it acts as a resistance surface to prevent over-settlement and uneven settlement due to the load of caisson body on clay soil and soft ground containing water, contributing to stable caisson's own-sink. In addition, at the site where there is groundwater etc., the sharp point at the bottom of the inverted triangle part is difficult to tip, and this surface (inward from the pointed part of the lower part rises inward and goes straight to the vertical line at the predetermined position. The extended part) is strongly grounded to minimize the inflow of groundwater during work, and efficient excavation work becomes possible.

The angle of the lower end of the inverted triangle is preferably 40 to 48 degrees depending on the type of ground. If the angle is less than 40 degrees, the resistance at the time of subsidence decreases, so the settlement becomes faster. Settlement slows down. The angle of the part rising outward from the lower end of the inverted triangle with respect to the vertical line passing through the tip of the inverted triangle is preferably in the range of -5 degrees to -0.5 degrees and +0.5 degrees to +5 degrees depending on the type of ground. However, when this angle is −, that is, when the upper end of the leading edge is outside the vertical line, it is preferable when the ground is sludge, etc., and when it exceeds −5 degrees, the settlement speed becomes too fast. On the contrary, when the angle is +, that is, when the upper end of the leading edge is inside the perpendicular, it is preferable when the ground is sand or gravel layer. If it becomes larger than +5 degrees, the settlement speed becomes slower. When it is 0 degree, friction is unstable and settlement accuracy is lowered.

The lower and outer mold panels of the caisson, that is, the space at the lower part of the mold filled with caisson concrete milk and the opening connected to the lower part of the caisson and communicating with the space between the outer frame and the inner frame at the upper part In order to enhance the strength, an inverted triangular hollow leading blade having a metal rod that passes through the opening and reaches the outer and inner formwork panel spaces of the caisson and the hollow portion of the leading blade is installed. Fill with concrete milk. At this time, it is sufficient to use a bar suitable for the site such as a single bar or a U-shaped bar.

The upper end that rises outward from the sharp point at the bottom of the inverted triangle is the lower end of the outer formwork panel of the caisson, the lower end of the caisson concrete part from which the outer formwork panel of the caisson is removed, or the protective layer formed on the concrete surface part. The predetermined length from the lower end of the surface is the vertical line of the outermost periphery of the leading blade, that is, the ground wall scraped by the leading blade and the outer formwork panel of the caisson or the outside of the concrete formed by removing the outer formwork panel Or after removing an outer formwork panel, the width | variety from the protective layer surface which formed the protective layer in the concrete surface should just be adjusted in the range of 20 mm to 200 mm. It is advisable to put aggregate in this part for the purpose of reducing friction during sinking. At that time, if it is 20 mm or less, the effect of reducing friction is small, and if it is 200 mm or more, the effect of reducing friction is too large. That is, by providing this aggregate layer, the weight of the caisson with the leading blade is stably settled.

In the lower part of the caisson, one or more fixing bars for connecting the joints may be provided in order to increase the bonding strength between the pressure plate and the caisson wall. The above-mentioned leading blade is installed over the entire circumference of the lower end of the caisson outer periphery. However, since the single blade is large and inconvenience of work occurs, it may be divided into several parts. The divided leading blade is a metal casing with a part of the upper surface opened, and the adjacent leading blades may be joined to each other with, for example, bolts and placed under the caisson.

What is described in claims 8 to 13 will be described. In the caisson where the outer wall of the basement is constructed on the ground and sinks under its own weight, a leading blade made of concrete may be provided at the lower end of the caisson including the inside. This leading edge concrete may be divided and produced at the factory and carried to the site, or it may be produced on site, and it may be selected according to the convenience of the site. This leading edge has a tip part with a sharp inverted triangular lower part, and the part that rises outward from the lower tip part rises to a predetermined height, and its upper end part is the lower part of the outer formwork panel of the caisson or the outer part of the caisson. After filling concrete milk between the frame panel and the inner formwork panel to form a concrete wall and then removing the outer formwork panel, it is vertical from the lower end of the outer surface of the caisson concrete or from the lower end of the surface of the protective layer formed on the concrete surface. What is necessary is just to provide the predetermined | prescribed length part orthogonal to a line. The part rising inward from the lower tip extends inward with a line perpendicular to the vertical line at a predetermined position, and the end of this line ends at the lower end inside the inner formwork panel or the outer formwork panel and inner form of the caisson What is necessary is just to form so that it may stand | start up to the caisson concrete inner surface lower end part after filling concrete milk between frame panels and forming a concrete wall, and removing the inner formwork panel.

The portion that rises inward from the pointed portion at the lower part of the inverted triangular portion of the leading blade and extends inward by a line perpendicular to the vertical line at a predetermined position can be a jack base receiving surface when leveling horizontally. Therefore, accurate frame assembly becomes possible. In addition, when caisson sinks under its own weight, it acts as a resistance surface to prevent over-settlement and uneven settlement due to the load of caisson body on clay soil and soft ground containing water, contributing to stable caisson's own-sink. In addition, at the site where there is groundwater etc., the sharp point at the bottom of the inverted triangle part is difficult to tip, and this surface (inward from the pointed part of the lower part rises inward and goes straight to the vertical line at the predetermined position. The extended part) is installed strongly, and the inflow of groundwater during work is stopped at the top and efficient excavation work becomes possible.

The angle of the lower end of the inverted triangle is preferably 40 to 48 degrees depending on the type of ground. If the angle is less than 40 degrees, the resistance at the time of subsidence decreases, so the subsidence speeds up. Conversely, if it exceeds 48 degrees, the resistance increases. Settlement slows down. The part rising from the lower end of the inverted triangle has a range of -5 degrees to -0.5 degrees and 0.5 degrees to 5 degrees depending on the ground type as well as the angle to the vertical line passing through the tip of the inverted triangle. Although it is preferable, when this angle is −, that is, when the upper end of the leading edge is outside the vertical line, it is preferable when the ground is sludge, etc., and when it exceeds −5 degrees, the settlement speed becomes too fast. On the contrary, when the angle is +, that is, when the upper end of the leading edge is inside the perpendicular, it is preferable when the ground is sand or gravel layer. If it becomes larger than +5 degrees, the settlement speed becomes slower. When it is 0 degree, friction is unstable and settlement accuracy is lowered.

The above-mentioned leading blade is installed over the entire circumference of the lower end of the caisson outer periphery. However, since the single blade is large and inconvenience of work occurs, it may be divided into several parts. The part rising from the lower tip of the leading blade rises to a predetermined height, and the upper end is filled with concrete milk between the lower part of the outer formwork panel of the caisson or between the outer formwork panel and the inner formwork panel of the caisson. The predetermined length that goes straight to the vertical line from the lower end of the outer surface of the caisson concrete from which the outer formwork panel was removed or from the lower end of the surface of the protective layer formed on the concrete outer surface of the caisson wall is the maximum length of the leading blade. Peripheral vertical lines, that is, leading blades.

In other words, the caisson where the outer formwork panel is removed after filling the concrete wall between the outer formwork panel of the ground and the outer formwork panel of the caisson or the outer formwork panel of the caisson and the inner formwork panel by forming the concrete wall. What is necessary is just to adjust so that the value of the surface part of a concrete outer surface or the surface part of the protective layer formed in this concrete surface part may be in the range of 20 mm to 200 mm. It is advisable to put aggregate in this part for the purpose of reducing friction during sinking. At that time, if it is 20 mm or less, the effect of reducing friction is small, and if it is 200 mm or more, the effect of reducing friction is too large. That is, by providing this aggregate layer, the weight of the caisson with the leading blade is stably settled. In the lower part of the caisson, one or more fixing bars for connecting the joints may be provided in order to increase the bonding strength between the pressure plate and the caisson wall.

Claims 1 to 8 according to the present invention, that is, when metal is used for at least a part of the leading edge, in the self-weight subsidence caisson method and underground structure, the outer wall of the basement is constructed on the ground, and the outer wall of the outer wall In the caisson that sinks its own weight by excavating the inner space, at least a part of the leading blade is made of metal and formed integrally with the caisson wall and the concrete inside the leading blade, so that the process is shortened and inexpensive. Furthermore, it is formed integrally, and it is advantageous in terms of strength and waterproofing by adding a metal reinforcing member as necessary. Furthermore, since there is a portion that rises inward from the pointed portion at the lower part of the leading-edge inverted triangle portion and extends inward at a portion at a predetermined position, it is advantageous in terms of horizontal leveling and is also advantageous for clay and In soft ground, it acts as a resistance surface to prevent over- and under-settlement caused by the caisson body load, contributing to stable caisson self-sedimentation. In addition, during the subsidence, the part extending inward along the line perpendicular to the vertical line is strongly grounded, so that the inflow of groundwater can be minimized and efficient excavation work becomes possible. Furthermore, since the pointed portion of the lower end of the inverted triangle can be selected optimally according to the situation at the site, it is possible to settle stably when sinking by excavation. Since the upper end rising from the sharp point at the lower part of the inverted triangular part has a predetermined length from the outer periphery of the caisson wall, an aggregate layer is formed on this part, and there is an effect of reducing friction and stable settlement is obtained. .

Claims 9 to 15, that is, even in the case where the leading blade is made of concrete, in the self-weight subsidence caisson method and the underground structure according to the present invention, the outer wall of the basement is configured on the ground, and the inner space of the outer wall is defined. The caisson that sinks its own weight by excavating is inexpensive because it is a leading blade made of concrete including the inside. In addition, there is a portion that rises inward from the pointed portion at the bottom of the inverted triangular portion of the leading blade and extends inward with a line perpendicular to the vertical line at a predetermined position, which is advantageous in terms of horizontal leveling and made of clay It acts as a resistance surface to prevent over- and under-settlement caused by the caisson body load on soil and soft ground, and contributes to stable caisson subsidence. In addition, during the subsidence, the part extending inward along the line perpendicular to the vertical line is strongly grounded, so that the inflow of groundwater can be minimized and efficient excavation work becomes possible. Furthermore, since the pointed portion of the lower end of the inverted triangle can be selected optimally according to the situation at the site, it is possible to settle stably when sinking by excavation. Since the upper end rising from the sharp point at the lower part of the inverted triangular part has a predetermined length from the outer periphery of the caisson wall, an aggregate layer is formed on this part, and there is an effect of reducing friction and stable settlement is obtained. .

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention and shows a cross section of a leading blade and a caisson when the ground is a gravel layer or the like. A portion 1 of the thick line is made of a metal such as iron. 2 is a caisson wall outer formwork panel, and 3 is a caisson wall inner formwork panel. 6 and 7 are portions connecting the leading edge metal part and the caisson formwork panel, and the upper part of the leading edge metal part has an opening, and the outer formwork panel of 2 caisson walls and the inside of the caisson wall of 3 The gap between the formwork panels and the leading blade space are continuous. By filling concrete milk as shown here, the leading blade space and the caisson wall are formed as continuous concrete. The leading blade metal part 9 is a part rising from the tip to the outside, 10 is a part rising from the tip to the inside, and 11 is a part perpendicular to the vertical line from the end of the part rising from the tip to the inside.

The leading edge of the leading edge has an inverted triangle pointed down, and the tip of the leading edge excavates the ground along the vertical line 8 by the weight of the caisson with the leading edge by excavating the inside of the caisson. Will be formed. 12 is a predetermined length between the leading edge outside rising upper end and the caisson outer formwork panel, and the determination of this predetermined length will be described later. Here, it is between the leading edge outer rising upper end part and the caisson outer formwork panel, but is not limited to this, and after the leading blade outer rising upper end part and concrete milk is filled to form the outer formwork panel It may be between the outside of the removed caisson concrete wall or between the rising edge of the leading blade outside and the surface of the protective layer formed on the surface of the concrete wall.

The angle of the tip varies depending on the type of ground. Here, in the case of a gravel layer, the angle of the lower part of the leading edge inverted triangle is 43 degrees as shown at 13, and the vertical line and the leading edge outside rising edge are similarly shown at 14. The angle is +3 degrees. Next, a method for further increasing the strength between the caisson wall and the leading blade will be described. Here, as shown in FIG. 5, a reinforcing reinforcing bar (metal) may be installed before filling with concrete milk.

Here, the shape of the metal portion is as shown in FIG. 1, but is not limited thereto. FIG. 2 shows other cases. Here, (a) is the same as FIG. 1, but (b) to (i) and the like are conceivable as other shapes. Here, the shapes of (a) to (j) are shown, but the present invention is not limited to this, and the metal portion is based on the shape of (j) at least, and other portions are replaced with metal portions as shown in (a) to (i). You may arrange according to the situation of the spot. Here, as an example, a method of making in the case of (j) will be described. This is shown in FIG. Here, the leading edge metal part is the part 1 of the thick line, and since there is no metal part, it will protrude when it is filled with concrete milk. Therefore, it is only necessary to provide a part of the mold 15 that is not covered by the leading edge metal part. As in (b) to (i), as in the case of (j), a part having no metal part may be provided with a mold.
Reference numeral 5 denotes a reinforcing reinforcing bar as in FIG.

In FIG. 2, all the leading blade metal portions 11 have a portion orthogonal to the vertical line from the end of the portion rising inward from the tip as in FIG. This part can be used as a jack base receiving surface when leveling out, so that an accurate frame can be assembled. In addition, when caisson sinks under its own weight, it acts as a resistance surface to prevent over-settlement and uneven settlement due to the load of caisson body on clay soil and soft ground containing water, contributing to stable caisson's own-sink. In addition, at the site where there is groundwater etc., the sharp point at the bottom of the inverted triangle part is difficult to tip, and this surface (inward from the pointed part of the lower part rises inward and goes straight to the vertical line at the predetermined position. The extended part) is strongly grounded to minimize the inflow of groundwater during work, and efficient excavation work becomes possible.

Next, the case where the ground is sludge or the like will be described. The situation is shown in FIG. 4 and shows a cross section of the leading blade and the caisson. The portion 21 of the thick line is made of a metal such as iron. Reference numeral 22 denotes a caisson wall outer formwork panel, and reference numeral 23 denotes a caisson wall inner formwork panel. Reference numerals 26 and 27 are portions connecting the leading blade metal part and the caisson formwork panel, and the upper part of the leading blade metal part has an opening, and 22 caisson wall outside formwork panels and 23 caisson wall inside. The gap between the formwork panels and the leading blade space are continuous. By filling concrete milk as shown here at 24, the leading blade space and the caisson wall are formed as continuous concrete. The leading blade metal part 29 is a part rising from the tip to the outside, 30 is a part rising from the tip to the inside, and 31 is a part perpendicular to the vertical line from the end of the part rising from the tip to the inside.

The leading blade has an inverted triangle with a sharp point on the bottom, and by excavating the inside of the caisson, the tip of the leading blade excavates the ground along the vertical line 28 by the weight of the caisson with the leading blade. Will be formed. Reference numeral 32 denotes a predetermined length between the leading edge outer rising upper end and the caisson outer form panel, and the determination of the predetermined length will be described later. Here, it is between the leading edge outer rising upper end part and the caisson outer formwork panel, but is not limited to this, and after the leading blade outer rising upper end part and concrete milk is filled to form the outer formwork panel It may be between the outside of the removed caisson concrete wall or between the rising edge of the leading blade outside and the surface of the protective layer formed on the surface of the concrete wall.

The angle of the tip varies depending on the type of ground. Here, in the case of sludge, etc., the angle of the leading blade inverted triangle is 47 degrees as shown at 33. Similarly, as shown at 34, the vertical line and the leading edge outside rising portion. The angle is -3 degrees. Next, a method of further increasing the strength between the caisson wall and the leading blade will be described. Here, as shown in 25, the reinforcing steel (metal) for strengthening the strength may be installed before filling with concrete milk.

Here, the shape of the metal part is as shown in FIG. 4, but is not limited thereto. FIG. 5 shows other cases. Here, (k) is the same as in FIG. 4, but (l) to (u), etc. are conceivable as other shapes. Although the shapes from (k) to (u) are shown here, the present invention is not limited to this, and the metal portion is based on the shape of at least (u), and the other portions are metal portions as shown in (l) to (t). You may arrange according to the situation of the spot. Here, (k) is the same as in FIG. 4, but (l) to (u), etc. are conceivable as other shapes. Here, as an example, a method of making in the case of (u) will be described. This is shown in FIG. Here, the leading edge metal portion is a portion 21 of a thick line, and since there is no metal portion, it will protrude when filled with concrete milk. Therefore, it is only necessary to provide a mold frame 35 when the leading edge metal portion is not covered. Similarly to the case of (u) from (l) to (t), a part having no metal part may be provided with a mold. Reference numeral 25 denotes a strength reinforcing steel bar as in FIG.

In FIG. 5, all the leading blade metal portions 11 have a portion orthogonal to the vertical line from the end of the portion rising inward from the tip as in FIG. This part can be used as a jack base receiving surface when leveling out, so that an accurate frame can be assembled. In addition, when caisson sinks under its own weight, it acts as a resistance surface to prevent over-settlement and uneven settlement due to the load of caisson body on clay soil and soft ground containing water, contributing to stable caisson's own-sink. In addition, at the site where there is groundwater etc., the sharp point at the bottom of the inverted triangle part is difficult to tip, and this surface (inward from the pointed part of the lower part rises inward and goes straight to the vertical line at the predetermined position. The extended part) is strongly grounded to minimize the inflow of groundwater during work, and efficient excavation work becomes possible.

FIG. 7 shows a state of a cross-section in which, in the case of the structure of FIG. 1, a fixing bar for connecting a joint portion is provided at the lower part of the caisson in order to increase the bonding strength between the pressure plate and the caisson wall. Here, 1 is a leading edge metal part, 4 is a caisson wall, and 16 is a fixing bar for connecting the joints in order to increase the bonding strength between the pressure plate and the caisson wall. Here, there is one fixing streak, but it is not limited to one, and a plurality of fixing streaks may be used. That is, two-stage reinforcement and three-stage reinforcement may be used. In addition, here, the leading edge is shown in the case of FIG. 1, that is, the ground is a gravel layer, but is not limited to this, and when the ground is sludge or the like, that is, in the case of FIG. That's fine.

FIG. 8 shows the arrangement of bars in the case of FIG. 2 (h). The cross section in the lower part of the caisson is provided with fixing bars for connecting the joints to increase the bonding strength between the pressure plate and the caisson wall. It shows a state. Here, 1 is a leading edge metal part, 4 is a caisson wall, and 16 is a fixing bar for connecting the joints in order to increase the bonding strength between the pressure plate and the caisson wall. Here, there is one fixing streak, but it is not limited to one, and a plurality of fixing streaks may be used. That is, two-stage reinforcement and three-stage reinforcement may be used. Further, here, the leading edge in the case of FIG. 1, that is, in the case where the ground is a gravel layer, is shown, but the present invention is not limited to this.

Next, since it is difficult to provide the leading blade over the entire circumference of the caisson, it may be divided into a plurality of leading blades. FIG. 9 shows a plan view of this state. Here, 41 is a divided leading blade, and 42 is a leading blade divided at a corner. Although an underground structure such as a rectangular basement is shown here, the present invention is not limited to this, and may be a circle, an ellipse, a polygon, or the like.

Next, it was formed between the upper edge of the leading edge outside mentioned above and the caisson outer formwork panel or between the outside of the caisson concrete wall where the outer formwork panel was removed after filling with concrete milk and forming concrete, or on the outer surface of the concrete wall. The predetermined length between the protective layer surfaces will be described. This state is shown in FIG. 10, but here, the predetermined length between the upper edge of the leading edge of the ground and the protective layer surface formed on the outer surface of the concrete wall will be described.

Here, 1 is the leading edge, and 4 is caisson concrete (concrete milk of concrete). 51 is an inner surface of caisson concrete, 52 is an outer surface of caisson concrete, and 53 protective layers for the purpose of waterproofing are provided on the outer surface of caisson concrete. 54 is the ground, and 55 is aggregate (sand etc.). Here, the aggregate plays a role of reducing resistance when the caisson with the leading blade sinks its own weight. The outermost peripheral part of the leading blade is a drilling surface 56 excavated along a vertical line passing through the outermost peripheral part of the leading blade of 58. And the predetermined length between the leading edge outside rising upper end part and the surface of the protective layer formed on the surface outside the concrete wall may be adjusted so that the width of the 57 aggregate layer is 20 mm to 200 mm. In this aggregate layer 55, the surrounding aggregate flows in along with the sinking of the leading blade caisson, the resistance is reduced, and the smooth sinking of the leading blade caisson is achieved. Although this description is for the case where the outermost peripheral portion of the caisson is the surface of the protective layer, the same applies to other cases. That is, it is adjusted between the excavation surface and the caisson outer formwork panel or between the caisson concrete wall outside after the outer formwork panel is removed after filling concrete milk to form concrete, that is, the aggregate layer width is 20 mm to 200 mm. That's fine. Although the case where the ground is a gravel layer has been described here, in the case of sludge or the like, it is between a vertical line passing through the outermost peripheral portion of the leading blade, that is, a vertical line passing through the leading edge outside rising edge. That is, the outermost peripheral portion of the leading blade is the leading edge outside rising upper end portion. Therefore, the protective layer surface formed between the upper edge of the leading blade outside and the caisson outer formwork panel or between the caisson concrete wall outside where the outer formwork panel was removed after filling concrete milk and forming concrete, or on the surface outside the concrete wall The predetermined length between them may be 20 mm to 200 mm.

And in the underground structure concerning this invention, it is an underground structure obtained by the self-weight subsidence type construction method concerning the above-mentioned this invention.

Next, the case where the leading blade is made of concrete will be described. FIG. 11 shows an embodiment of the present invention and shows a cross section of the leading edge and the caisson when the ground is a gravel layer. 61 is a leading edge made of concrete. 62 is a caisson wall outer formwork panel, and 63 is a caisson wall inner formwork panel. 69 is a part rising from the tip to the outside, 70 is a part rising from the tip to the inside, and 71 is a part perpendicular to the vertical line from the end of the part rising from the tip to the inside.

This part can be used as a jack base receiving surface when leveling out, so that an accurate frame can be assembled. In addition, when caisson sinks under its own weight, it acts as a resistance surface to prevent over-settlement and uneven settlement due to the load of caisson body on clay soil and soft ground containing water, contributing to stable caisson's own-sink. In addition, at the site where there is groundwater etc., the sharp point at the bottom of the inverted triangle part is difficult to tip, and this surface (inward from the pointed part of the lower part rises inward and goes straight to the vertical line at the predetermined position. The extended part) is strongly grounded to minimize the inflow of groundwater during work, and efficient excavation work becomes possible.

The leading blade has an inverted triangle with a sharp point on the bottom, and by excavating the inside of the caisson, the tip of the leading blade excavates the ground along the vertical line 68 by the weight of the caisson with the leading blade. Will be formed. Reference numeral 72 denotes a predetermined length between the leading edge outer rising upper end portion and the caisson outer form panel, and determination of this predetermined length will be described later. Here, it is between the leading edge outer rising upper end part and the caisson outer formwork panel, but is not limited to this, and after the leading blade outer rising upper end part and concrete milk is filled to form the outer formwork panel It may be between the outside of the removed caisson concrete wall or between the rising edge of the leading blade outside and the surface of the protective layer formed on the surface of the concrete wall.

The angle of the tip varies depending on the type of ground. Here, in the case of a gravel layer, as shown at 73, the angle at the lower part of the leading blade inverted triangle is 43 degrees, and similarly as shown at 74, the vertical line and the leading edge outside rising portion. The angle is +3 degrees. Next, a method for further increasing the strength between the caisson wall and the leading blade will be described, and this is shown in FIGS. In FIG. 12, 61 is a concrete leading blade, and 65 is a reinforcing bar protruding from the concrete leading blade. FIG. 13 shows a state in which the concrete leading blade and the caisson wall are strengthened, and 65 shows a state in which a reinforcing bar enters the concrete leading blade and the caisson wall. The other parts are the same as in FIG. 11, 62 is a caisson wall outer formwork panel, and 63 is a caisson wall inner formwork panel. 69 is a part rising from the tip to the outside, 70 is a part rising from the tip to the inside, and 71 is a part perpendicular to the vertical line from the end of the part rising from the tip to the inside.

The leading blade has an inverted triangle with a sharp point on the bottom, and by excavating the inside of the caisson, the tip of the leading blade excavates the ground along the vertical line 68 by the weight of the caisson with the leading blade. Will be formed. Reference numeral 72 denotes a predetermined length between the leading edge outer rising upper end portion and the caisson outer form panel, and determination of this predetermined length will be described later. Here, it is between the leading edge outer rising upper end part and the caisson outer formwork panel, but is not limited to this, and after the leading blade outer rising upper end part and concrete milk is filled to form the outer formwork panel It may be between the outside of the removed caisson concrete wall or between the rising edge of the leading blade outside and the surface of the protective layer formed on the surface of the concrete wall.

The angle of the tip varies depending on the type of ground. Here, in the case of a gravel layer, as shown at 73, the angle at the lower part of the leading blade inverted triangle is 43 degrees, and similarly as shown at 74, the vertical line and the leading edge outside rising portion. The angle is +3 degrees.

Next, the case where the ground is sludge or the like will be described. FIG. 14 shows a cross section of the leading blade and the caisson. A portion 81 is a leading blade made of concrete. 82 is a caisson wall outer formwork panel, and 83 is a caisson wall inner formwork panel. 89 is a part rising from the tip to the outside, 90 is a part rising from the tip to the inside, and 91 is a part perpendicular to the vertical line from the end of the part rising from the tip to the inside.

This part can be used as a jack base receiving surface when leveling out, so that an accurate frame can be assembled. In addition, when caisson sinks under its own weight, it acts as a resistance surface to prevent over-settlement and uneven settlement due to the load of caisson body on clay soil and soft ground containing water, contributing to stable caisson's own-sink. In addition, at the site where there is groundwater etc., the sharp point at the bottom of the inverted triangle part is difficult to tip, and this surface (inward from the pointed part of the lower part rises inward and goes straight to the vertical line at the predetermined position. The extended part) is strongly grounded to minimize the inflow of groundwater during work, and efficient excavation work becomes possible.

The leading blade has an inverted triangle with a sharp point on the bottom, and by excavating the inside of the caisson, the tip of the leading blade excavates the ground along the vertical line 88 by the weight of the caisson with the leading blade. Will be formed. Reference numeral 92 denotes a predetermined length between the leading edge outer rising upper end and the caisson outer form panel, and the determination of the predetermined length will be described later. Here, it is between the leading edge outer rising upper end part and the caisson outer formwork panel, but is not limited to this, and after the leading blade outer rising upper end part and concrete milk is filled to form the outer formwork panel It may be between the outside of the removed caisson concrete wall or between the rising edge of the leading blade outside and the surface of the protective layer formed on the surface of the concrete wall.

The angle of the tip varies depending on the type of ground. Here, in the case of sludge, etc., the angle of the lower part of the leading edge inverted triangle is 47 degrees as shown by 93, and the vertical line and the leading edge outside rising part are similarly shown by 94. The angle is -3 degrees. Next, a method for further increasing the strength between the caisson wall and the leading blade will be described, and this is shown in FIGS. In FIG. 15, 81 is a concrete leading blade, and 85 is a reinforcing bar protruding from the concrete leading blade. FIG. 16 shows a state in which the concrete leading blade and the caisson wall are strengthened, and 85 shows a state in which a reinforcing bar enters the concrete leading blade and the caisson wall. The other parts are the same as in FIG. 14, 82 is a caisson wall outer formwork panel, and 83 is a caisson wall inner formwork panel. 89 is a part rising from the tip to the outside, 90 is a part rising from the tip to the inside, and 91 is a part perpendicular to the vertical line from the end of the part rising from the tip to the inside.

The leading blade has an inverted triangle with a sharp point on the bottom, and by excavating the inside of the caisson, the tip of the leading blade excavates the ground along the vertical line 88 by the weight of the caisson with the leading blade. Will be formed. Reference numeral 92 denotes a predetermined length between the leading edge outer rising upper end and the caisson outer form panel, and the determination of the predetermined length will be described later. Here, it is between the leading edge outer rising upper end part and the caisson outer formwork panel, but is not limited to this, and after the leading blade outer rising upper end part and concrete milk is filled to form the outer formwork panel It may be between the outside of the removed caisson concrete wall or between the rising edge of the leading blade outside and the surface of the protective layer formed on the surface of the concrete wall.

The angle of the tip varies depending on the type of ground. Here, in the case of sludge, etc., the angle of the lower part of the leading edge inverted triangle is 47 degrees as shown by 93, and the vertical line and the leading edge outside rising part are similarly shown by 94. The angle is -3 degrees.

FIG. 17 shows a state of a cross section in which a fixing bar for connecting a joint portion is provided at the lower part of the caisson in the structure of FIG. 11 in order to increase the bonding strength between the pressure plate and the caisson wall. Here, 61 is a leading edge metal part, 64 is a caisson wall, and 74 is a fixing bar for connecting the joining portions in order to increase the bonding strength between the pressure plate and the caisson wall. Here, there is one fixing streak, but it is not limited to one, and a plurality of fixing streaks may be used. That is, two-stage reinforcement and three-stage reinforcement may be used. 11 shows the leading edge when the ground is a gravel layer. However, the present invention is not limited to this, and when the ground is sludge or the like, that is, the case shown in FIG. That's fine.

Next, since it is difficult to provide the leading blade over the entire circumference of the caisson, it may be divided into a plurality of leading blades, but a plan view of this state is shown in FIG. Here, 101 is a divided leading blade, and 102 is a leading blade divided at a corner. Although an underground structure such as a rectangular basement is shown here, the present invention is not limited to this, and may be a circle, an ellipse, a polygon, or the like.

Next, it was formed between the upper edge of the leading edge outside mentioned above and the caisson outer formwork panel or between the outside of the caisson concrete wall where the outer formwork panel was removed after filling with concrete milk and forming concrete, or on the outer surface of the concrete wall. The predetermined length between the protective layer surfaces will be described. The situation is shown in FIG. 16, but here, the ground is a gravel layer, and the predetermined length between the upper edge of the leading edge and the surface of the protective layer formed on the outer surface of the concrete wall will be described. Is between the vertical line passing through the outermost periphery of the leading blade, that is, the vertical line passing through the leading edge outside rising edge.

Here, 61 is a concrete leading blade, and 64 is caisson concrete (concrete milk of concrete). 111 is a caisson concrete inner surface, 112 is a caisson concrete outer surface, and 113 protective layers for the purpose of waterproofing are provided on the caisson concrete outer surface. 114 is the ground, and 115 is aggregate (sand etc.). Here, the aggregate plays a role of reducing resistance when the caisson with the leading blade sinks its own weight. The outermost peripheral part of the leading edge is an excavation surface 116 excavated along a vertical line passing through the outermost peripheral part of 118 leading blades. And the predetermined length between the leading edge outer rising upper end part and the surface of the protective layer formed on the outer surface of the concrete wall may be adjusted so that the width of the 117 aggregate layer is 20 mm to 200 mm. In this aggregate layer 115, the surrounding aggregate flows in along with the sinking of the caisson with the leading blade, the resistance is reduced, and the smooth sinking of the caisson with the leading blade is achieved.

Although this description is for the case where the outermost peripheral portion of the caisson is the surface of the protective layer, the same applies to other cases. That is, it is adjusted between the excavation surface and the caisson outer formwork panel or between the caisson concrete wall outside after the outer formwork panel is removed after filling concrete milk to form concrete, that is, the aggregate layer width is 20 mm to 200 mm. That's fine. Although the case where the ground is a gravel layer has been described here, in the case of sludge or the like, it is between a vertical line passing through the outermost peripheral portion of the leading blade, that is, a vertical line passing through the leading edge outside rising edge. That is, the outermost peripheral portion of the leading blade is the leading edge outside rising upper end portion. Therefore, the protective layer surface formed between the upper edge of the leading blade outside and the caisson outer formwork panel or between the caisson concrete wall outside where the outer formwork panel was removed after filling concrete milk and forming concrete, or on the surface outside the concrete wall The predetermined length between them may be 20 mm to 200 mm.

And in the underground structure concerning this invention, it is an underground structure obtained by the self-weight subsidence type construction method concerning the above-mentioned this invention.

Cross section of metal leading blade and caisson in case of gravel layer Variation of leading edge metal part in case of gravel layer, etc. Cross-section of leading blade and caisson for leading blades with different metal parts such as gravel layers Cross section of metal leading blade and caisson in case of sludge Variation of leading edge metal parts such as sludge Cross-section of leading blade and caisson for leading blades with different metal parts such as sludge Stabilizing muscle that connects caisson and pressure board 1 Anchor muscle connecting caisson and pressure-resistant board 2 Top view of leading blade division Relationship between leading edge outside rising edge and caisson Cross section of concrete leading blade and caisson in case of gravel layer Concrete leading blade with reinforcing bars in the case of gravel layers Cross section of leading blade and caisson reinforced by reinforcing bars in case of gravel layer In the case of sludge, etc. In case of sludge etc. In the case of sludge, etc. The anchor muscle that connects the caisson and the pressure board Top view of leading blade division Relationship between leading edge outside rising edge and caisson

1 Leading edge metal part
2 Caisson outer formwork
3 Caisson inner formwork
4 Concrete milk (concrete)
5 Reinforcing bars (metal)
・ Leading blade and caisson formwork joint
8 Vertical line (excavation surface)
9 The part that rises outward from the tip
10 Part rising from tip end 11 Part rising from tip end part perpendicular to vertical line from end of end 12 Predetermined length between leading edge outside rising edge and caisson outer formwork panel 13 Angle of lower part of leading edge inverted triangle 43 degrees
14 Vertical line and leading edge outside rising part angle + 3 degrees
15 Formwork 16 in the case where the metal part of the leading blade is not covered Fixing bar 21 for connection to the pressure platen Leading metal part
22 Caisson outer formwork
23 Caisson inner formwork
24 Concrete milk 25 Strengthening reinforcement (metal)
26, 27 Leading blade and caisson formwork joint
28 Vertical line 29 The part that rises outward from the tip
30 A portion rising inward from the tip 31 A portion rising inward from the tip A portion perpendicular to the vertical line from a terminal end 32 An outer rising upper end portion and a caisson outer panel 33 An angle of 47 degrees below the leading edge inverted triangle
34 Vertical line and leading edge outside rising part angle −3 degrees 35 Formwork 41 when the leading edge metal part does not cover Divided leading edge 42 Divided leading edge corner 51 Cane concrete inner surface 52 Caisson concrete outer surface
53 Protective layer
54 Ground
55 Aggregate (sand, etc.)
56 Drilling surface
57 Aggregate layer (20mm ~ 200mm)
58 Vertical line passing through the outermost periphery of the leading edge 61 Concrete leading edge
62 Caisson outer formwork
63 Caisson inner formwork
64 Concrete milk 65 Reinforcing bar 69 coming out from the concrete leading blade
70 A part rising from the tip 71 A part rising from the tip inside A part 72 perpendicular to the vertical line from a terminal end 72 A predetermined length 73 between the leading edge outside rising upper end and the caisson outer panel Vertical line 74 For connection to the pressure platen Anchor muscle 69 Leader blade inverted triangle bottom angle 43 degrees
74 Vertical line and leading edge outside rising angle +3 degrees
81 Concrete leading blade
82 Caisson outer formwork
83 Caisson inner formwork
84 Concrete milk
85 Reinforcing bar 88 coming out from concrete leading blade Vertical line 89 A part rising from the tip to the outside
90 A portion rising inward from the tip 91 A portion perpendicular to the vertical line from a terminal end rising inward from the tip 92 A predetermined length 93 between the leading edge outside rising upper end portion and the caisson outer panel 93 Vertical line
69 Angle of the leading edge of the inverted triangle 47 degrees below
94 Vertical line and leading edge outside rising portion angle −3 degrees 101 Divided leading blade 102 Divided leading blade corner 111 Caisson concrete inner surface 112 Caisson concrete outer surface
113 Protective layer
114 ground
115 Drilling surface
116 Aggregate (sandbox)
117 Vertical line passing through the outermost periphery of the leading blade
118 Aggregate layer (20mm ~ 200mm)

Claims (15)

A caisson that is constructed of an outer peripheral wall housing of a basement on the ground and sinks its own weight by excavating an inner space of the outer wall housing, and at least a part thereof is made of metal at the lower end portion of the caisson. An inverted triangular hollow leading blade having an opening joined to the panel and having an opening communicating with the space between the outer frame and the inner frame at the upper portion is provided, and the outer side from the sharp portion of the lower portion of the inverted triangular portion of the leading blade cross section The upper end of the caisson is formed up to the intersection with the line perpendicular to the vertical line through the lower end of the outer form panel of the caisson. The portion extending inwardly at a position perpendicular to the vertical line is at least metal, and the hollow portion of the leading blade below the caisson and the outer and inner formwork panels at the same time are simultaneously formed. By filling concrete milk, it has a concrete part that continues from the hollow part of the leading blade to the space between the outer and inner formwork panels, and rises from the sharp part of the lower part of the inverted triangular part to the outside, and the upper end part of the caisson Self-weight subsidence characterized by having a predetermined length from the lower end of the outer formwork panel or the lower end of the caisson concrete part from which the outer formwork panel of the caisson is removed or the lower end of the surface of the protective layer formed on the concrete surface part Type caisson method The self-weight subsidence caisson method according to claim 1, wherein the angle of the lower end of the inverted triangle is 40 to 48 degrees depending on the type of ground. The portion rising outward from the lower end of the inverted triangle is −5 ° to −0.5 ° and + 0.5 ° to + 5 ° with respect to the vertical line passing through the tip of the inverted triangle, depending on the type of ground. 3. Self-weight subsidence caisson method according to claim 1 or 2 An inverted triangular hollow leading blade joined to the outer and inner mold panels at the lower end of the caisson and having an opening communicating with the space between the outer frame and the inner frame in the upper portion is a leading blade for strengthening the strength. A metal bar which passes through the upper opening of the caisson and reaches the space part of the outer and inner form panel of the caisson and the hollow part of the leading blade is installed and filled with concrete milk. Self-weight subsidence caisson method according to claims 1 to 3 The upper end portion that rises outward from the pointed portion of the lower part of the inverted triangular portion is formed at the lower end of the outer formwork panel of the caisson, the lower end of the caisson concrete part from which the outer formwork panel of the caisson is removed, or the concrete surface part. The predetermined length from the lower end portion of the surface of the protective layer is the vertical line of the outermost peripheral portion of the leading blade and the outer formwork panel of the caisson or the outer formwork panel of concrete formed by removing the outer formwork panel. The width from the surface of the protective layer in which the protective layer is formed on the concrete surface after being removed is adjusted to be in the range of 20 mm to 200 mm and the vertical line of the outermost peripheral part of the leading blade and the outer formwork panel of the caisson or the above After removing the outer formwork panel, the outside of the formed concrete or after removing the outer formwork panel Own weight settlement type caisson method of claims paragraphs 1 through 4 wherein wherein the provision of the aggregate layer for width portion to reducing the friction from the protective layer surface to form a protective layer on the surface 6. The self-weight subsidence caisson method according to claim 1, wherein the caisson lower part has one or more fixing bars for connecting a joint portion with a pressure-resistant plate. The self-weight subsidence caisson method according to any one of claims 1 to 6, wherein the leading blade is divided and adjacent leading blades are joined and installed at the lower part of the caisson. An underground structure obtained by the self-weight subsidence caisson method according to any one of claims 1 to 7. In the caisson where the outer wall of the basement is constructed on the ground and sinks under its own weight, a leading blade made of concrete is provided at the lower end portion of the caisson, and the leading blade has a tip with a pointed bottom of an inverted triangle. The portion that rises outward from the lower tip is raised to a predetermined height, and the upper end is filled with concrete milk between the lower end of the outer formwork panel of the caisson or between the outer formwork panel and the inner formwork panel of the caisson. A predetermined length portion perpendicular to the vertical line from the lower end of the outer surface of the caisson concrete from which the outer formwork panel is removed after forming the wall or from the lower end of the surface of the protective layer formed on the concrete surface, The portion that rises inward from the lower front end extends inward at a predetermined position and extends perpendicularly to the vertical line, and the end of the line is the inner mold panel. It is formed to stand vertically up to the inner surface of the caisson concrete where the inner formwork panel is removed after filling the concrete milk between the outer formwork panel and the outer formwork panel of the caisson between the inner formwork panel and forming the concrete wall. Self-weight subsidence caisson method The self-weight subsidence caisson method according to claim 9, wherein the angle of the lower end of the inverted triangle is 40 to 48 degrees depending on the type of ground. The portion rising outward from the lower end of the inverted triangle is −5 ° to −0.5 ° and + 0.5 ° to + 5 ° with respect to the vertical line passing through the tip of the inverted triangle, depending on the type of ground. Self-weight subsidence caisson method according to claims 9 to 10 The self-weight subsidence caisson method according to claims 9 to 11, wherein the leading blade is divided and adjacent leading blades are joined and installed at the lower part of the caisson. The part rising to the outside rises up to a predetermined height, and the upper end is the outer side after the concrete wall is formed by filling concrete milk between the lower part of the outer form panel of the caisson or between the outer form panel and the inner form panel of the caisson. The predetermined length perpendicular to the vertical line from the lower end of the outer surface of the caisson concrete with the formwork panel removed or from the lower end of the surface of the protective layer formed on the concrete surface is the vertical line of the outermost peripheral part of the preceding blade The caisson outer formwork panel or the caisson outer formwork panel and the inner formwork panel are filled with concrete milk to form a concrete wall, then the outer formwork panel is removed and formed on the outer surface of the caisson concrete or the concrete surface. Adjusted so that the width of the surface portion of the protective layer is in the range of 20 mm to 200 mm A protective layer was formed on the concrete surface after removing the vertical line of the outermost periphery of the leading blade and the outer formwork panel of the caisson or the outer formwork panel of the concrete formed by removing the outer formwork panel. The self-weight subsidence caisson method according to claims 9 to 12, wherein an aggregate layer is provided in a width portion from the surface of the protective layer to reduce friction. 14. The self-weight subsidence caisson method according to claim 9, wherein the caisson lower part has one or more fixing bars for connecting a joint portion with a pressure plate. The underground structure obtained by the self-weight subsidence caisson method according to any one of claims 9 to 14.

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