JP4875318B2 - Protection method for the foundation of floating structures - Google Patents

Description

  The disclosed technology is constructed by technologies such as railway bridges and road bridges that are permanently used, such as rivers in permanent structures and intricate coastline steps, and aging direct foundations and caisson foundations. Prevents adverse effects on the foundation of the structure due to scouring and other scouring, which is the most common cause of damage to bridges due to the influence of running water, etc., and the soundness of new construction of the floating structure Is in the technical field of securing and repairing and refreshing existing structures.

In Japan's humid climate, it is an island country and has many mountainous areas. Therefore, large and small lakes and rivers are ubiquitous across the country, and they are surrounded by intricate harbors due to wave erosion, sandbars and fan formation. In the civil engineering business that has been undertaken to build a dense road network that will serve as a foundation for life and industry in the terrain that is being developed, floating structures such as railway bridges and road bridges have been newly constructed. On the other hand, many of the structures built before the high economic growth period of the Meiji, Taisho, and early Showa eras are still in use at the beginning of the new century, and many of these structures supported the modernization of Japan. While it is a cultural heritage that leaves a footstep in civil engineering projects, it is steadily aging and weathering the foundation.
Against this backdrop, there is now a common recognition that these structures need to minimize the impact of running water with the development of hydraulics and river engineering. It is constructed with a direct foundation or caisson foundation with shallow penetration made with technology that is undeveloped from the technical level, and the span is short and the number of piers is large, so damage to old bridges with high river blockage rate is large I know.

  On the other hand, despite the importance of these floating structures, gravel collection of large rivers (during the period of high economic growth over the 1950s and 1940s) where river engineering design ideas were immature, Along with the artificial alteration of the river environment due to the progress of construction of sabo dams and multipurpose dams as countermeasures for mountain conservation, the progress of river bed degradation due to the drastic decrease in the supply of gravel and the rapid flow of rivers flowing in deep valleys of steep mountains In many of Japan, in the case of frequent floods in recent years, the foundations of scouring and sucking out sediments, etc., combined with the local increase in precipitation due to recent weather changes due to rolling up of gravel on the riverbed and rolling. Is underway and is currently at risk of collapse due to scouring.

  In addition, many of them are infrastructures for transportation such as railway bridges and road bridges, and have a structure that requires strong, safety, performance, and durability for the purpose of having high publicity that forms the foundation of life and industry. And advanced risk management technology is required.

  On the other hand, considering the aging of Japan's population and economic stagnation, construction costs will be reduced from a long-term perspective by introducing concepts such as life cycle costs and asset management. As attempts are made, new construction must be constrained and thorough effective use of assets must be practiced.

  In the background as described above, especially when existing structures such as bridges have left the scouring, there is a risk of losing stability and bearing capacity. Cost and time comparable to the main construction cost, such as turning over the current traffic for replacement in the metropolitan area of Tokyo and the bridges connecting them, and securing the site of the installation road for the temporary bridge In many cases, effective measures were required.

[First background]
The influence of the floating structure on the running water performance is mainly due to lack of bearing capacity, reduction of safety factor against horizontal force and moment, and increase of pile head moment. In the case of direct foundation or pile foundation, surround the footing with a sheet pile, steel pipe sheet pile, underground underground wall, etc. to the supporting ground that can be press-fitted such as hydraulic hammer, vibro hammer, etc., and the head is integrated with the footing or inside A method of constructing grout is common.

[Second background]
For direct foundations on bedrock that do not contain sheet piles, all casing construction for hard ground or ground auger construction is used for pre-displacement excavation and ground agitation to create good quality ground (ground that can be pressed well), then press sheet piles In addition, measures such as hardening the ground that has been loosened for penetration by chemical injection, etc. are being carried out. Because of the nature of the river, it is often in a river or dam lake that is a lifeline) There are problems such as concern for environmental impact and re- (secondary) scouring of the replacement excavation part, which is not a sufficient measure In general, after local scouring, it is filled with leveled concrete and filled with concrete buried in the ground to prevent scouring near the foundation.

[Third background]
Also, caisson is near the lower edge of the blade edge due to the structural requirements that the blade edge must be deeper than the direct foundation and the difficulty of securing deep rooting with immature conventional technology in hard ground. In some cases, scouring has spread to the ground near the edge where the scouring has lost its cohesiveness by taking measures such as blasting together, making drastic scouring countermeasures difficult.
Furthermore, as a conventional countermeasure against such scouring, scouring prevention by covering the scouring part using rubble or scraps is performed. It is conceivable that the intervention of hard and heavy covering materials such as rubble and shears that have been dug makes it difficult to take measures.
Such scouring prevention treatment of the caisson foundation having a deep lower end is particularly difficult to deal with, and measures such as a method of constructing a large-diameter pile around the caisson body and rigidly connecting it are performed.

  Many conventional foundation protection measures have been constructed, but few have been drastically improved, many of which have become temporary life extension measures that have been replaced in a relatively short period of time. In view of the fact that the cost is high, the present invention has a limitation that the treatment has to be completed in a relatively shallow layer due to difficulty in securing the root of the hard ground and rock in the conventional river bed. Overcoming the problem, it is strong against scouring without replacement excavation that impairs the solidity of the ground to hard ground (highly solidified earth and sand ground, river bed sediment layer that contains a lot of boulders and cobblestones, bedrock layer) In addition, by driving a steel pipe sheet pile with sufficient rigidity, we provide a simple and thorough scouring and low-cost structure that supports the suction of soil and sediments, and reliable rapid construction, to preserve assets, While ensuring the safety of rivers and harbors It is an object to improve the improvement and landscape throat structure foundation surrounding environment.

Such a problem is solved by the present invention described in the following (1) to (24).
The pile material in the present invention is, for example, a steel pipe main pipe and a steel material provided with joints on the side surfaces, which have been used for the foundation of earth retaining, deadlines and structures in the related art. In addition to the shape that conforms to the steel pipe sheet pile specifications currently defined in the Japanese Industrial Standard (JIS A 5530), the material does not necessarily conform to the above product standards, and has a structure with a main pipe diameter and joint shape. Thus, all the steel materials that are equivalent in function of constituting the wall body are indicated.

(1) A method for protecting the foundation of a floating structure from the influence of flowing water,
Pile material is penetrated into the original ground consisting of either hard ground or rock mass against resistance to penetration, and at that time, the pile material is connected to the pile material already placed,
By repeating the intrusion process, a wall body composed of a plurality of pile materials is constructed so as to face the above water structure foundation,
A method for protecting a water structure foundation, wherein each pile material forming the wall is supported by the raw ground.

(2) By constructing a wall structure composed of a plurality of pile members so as to surround the periphery of the water structure foundation by repeating the penetration step, the water structure foundation described in the above (1) Protection method.

(3) Each pile material constituting the wall has a main pipe and a joint,
Prior to the penetration of each pile material, the target ground is excavated in advance,
In the preceding excavation process,
The method for protecting a foundation of a floating structure according to (1) above, wherein a drilling hole diameter is determined in advance according to the hardness of the original ground, and excavation is performed with any one of the following drilling hole diameters a to c.
a: Diameter slightly below the diameter of the main pile material b: Diameter approximately equal to the diameter of the main pile material (a <b)
c: Diameter slightly larger than the diameter of the main pile (b <c)

(4) Each pile material forming the wall has a main pipe and a joint,
Prior to the penetration of each pile material, the target ground is excavated in advance,
In the preceding excavation process,
The method for protecting a foundation of a floating structure according to (1) above, wherein the drilling diameter is determined in advance according to the hardness of the original ground, and excavation is performed with any of the following drilling diameters d to g.
d: Diameter slightly below the joint part of the pile material e: Almost the same diameter as the joint part of the pile material (d <e)
f: Diameter slightly larger than the joint part of the pile material (e <f)
g: Diameter encompassing the entire two joints in the connected state (f <g)

(5) Each pile material constituting the wall has a main pipe and a joint,
In the penetration step, the pile material is penetrated into the ground using a press-fitting machine, and in this case, the pile material is dug together as a press-fitting aid. Protective method.

(6) The method for protecting a water structure foundation according to the above (1), wherein a rooting material is injected into the ground supporting the penetrated pile material.

(7) A wall structure for protecting the foundation of a floating structure from the influence of flowing water,
Combining multiple piles with joints,
Provided to face the above water structure foundation,
A wall structure characterized in that each pile material is intruded into an original ground composed of either hard ground or bedrock.

(8) The wall structure according to (7) above, wherein the joint portion of the pile material that has penetrated reaches the original ground.

(9) The wall structure according to (7) above, wherein the lower part of the protective floor structure covering the river bed and the pile material are combined.

(10) Each pile material constituting the wall has a main pipe and a joint,
In the part protruding from the ground of the wall structure,
The above-mentioned (7), characterized in that the wall structure facing the above-mentioned water structure foundation is provided with a water-permeable opening in at least one of the main pipe and the joint of the pile material. Wall structure described.

(11) Each pile material forming the wall has a main pipe and a joint,
In the part protruding from the ground of the wall structure,
The above (7) is characterized in that the wall structure facing the above-mentioned water structure foundation part has a gap through which water can flow freely by noting at least one row of main pipes or joints of pile material. Wall body structure.

(12) Each pile material constituting the wall has a main pipe and a joint,
In the part protruding from the ground of the wall structure,
The wall structure facing the above-mentioned water structure foundation has an opening or a gap through which water can freely pass,
The wall structure according to (7) above, wherein the opening or gap is covered with a net-like structure.

(13) The wall structure according to (12), wherein an end portion of the mesh structure is fixed by being inserted into a slit portion of the pile material.

(14) A wall structure for protecting the foundation of a floating structure from the influence of flowing water,
It consists of connecting multiple piles,
A wall structure constructed so as to face the water structure foundation so as to block a water flow toward the water structure foundation.

(15) All or part of the plurality of pile members constituting the wall structure is arranged so as to draw a substantially V shape or a parabola when viewed from above,
The pile material located at the top of the substantially V-shaped arrangement or the parabolic arrangement is located upstream of the other pile materials,
The wall structure according to (14), wherein the water structure foundation is located downstream of the pile material at the top.

(16) The wall structure according to (14), wherein the wall structure is constructed so as to surround the periphery of the water structure foundation.

(17) A method for constructing a wall body structure according to any one of (7) to (16) above,
Each pile material constituting the wall body has a main pipe, a joint main pipe and a joint,
A method for constructing a wall structure, characterized in that each pile is placed by a down-the-hole hammer.

(18) A step is provided on the inner wall of the pile material,
A step is provided at the top of the drill bit of the down-the-hole hammer,
Insert the down-the-hole hammer into the pile material, and perform excavation with the down-the-hole hammer,
In the drilling process by the down-the-hole hammer,
When the hammer sinks with the progress of excavation by hammering, the step on the excavator side and the step on the pile material side interfere with each other, and as a result, the pile material follows the preceding excavation in the direction of advancement. The method for constructing a wall structure according to the above (17), wherein the wall structure is press-fitted.

(19) A drilling rig used in the method according to (17) or (18) above,
The down-the-hole hammer excavation bit is configured to expand and contract,
In the state set in the reduced diameter position, the maximum outer circumference in the direction perpendicular to the excavation axis can be inserted into the inner space of the pile material,
The excavator characterized in that the outer periphery forming the drilling surface of the excavation bit is substantially the same diameter as or slightly larger than the pile material main pipe diameter in the state set in the expanded diameter position.

(20) A pile material used in the method or wall structure according to any one of (1) to (18) above,
A main pipe made of steel pipe,
A joint fixed to the main pipe and engaged with a joint of adjacent piles;
A pile material comprising: a water flow control means for controlling a downward water flow along an outer wall of the pile material.

(21) The pile material according to (20) above, wherein the water flow control means is composed of a plate or a projection protruding from the outer wall of the pile material.

(22) The pile material according to (21), wherein the plate is formed in a bowl shape projecting around the pile material.

(23) The pile material according to (20), wherein the water flow control means includes an outer wall of a pile material processed into an uneven shape.

(24) A pile material used in the method or wall structure according to any one of (1) to (18) above,
A main pipe made of steel pipe,
A joint fixed to the main pipe and engaged with a joint of adjacent piles,
A pile material, wherein a water-permeable opening or slit is formed in at least one of the main pipe and the joint.

According to the present invention described in the above (1) and (2), when the steel pipe sheet pile wall is constructed around the existing pier for the purpose of protecting the foundation of the floating structure from the influence of flowing water, the solid ground is consolidated. Or the strength of the original ground formed from the rock, and further, according to the invention described in (3) above, the replacement preceded by a larger diameter than the circumference including the cross section of the steel pipe sheet pile Since there is no excavation, the strength of the original ground can be expected, it is not affected by flowing water, and it is not affected by flowing water, and the hard ground cannot be penetrated by conventional hydraulic hammers, vibratory hammers, etc. By securing the support portion of the wall body, it becomes possible to ensure the stability and durability of the wall structure at a low cost.
In addition, this wall body does not necessarily share the supporting force of the floating structure main body such as the steel pipe sheet pile well foundation, and is intended to protect the foundation from the influence of flowing water. Compared to the structure that bears the load of the main body), it is possible to reduce the penetration length as much as possible and to make the steel pipe sheet pile diameter as small as possible. Designing the penetration length into can also be freely chosen.
In addition, a range limited to the vicinity of the joint for the purpose of reducing the penetration resistance of the joint, which is a structure unique to steel pipe sheet piles (approximately the same diameter as the joint pipe diameter, a diameter approximately equal to or less than or equal to the joint diameter, The structure that secures the support layer in the hard formation layer with high penetration resistance while maintaining the solidity of the ground by pre-excavating and performing sand replacement etc. It becomes possible to provide.

According to the present invention described in the above (5), it is possible to perform the press-fitting with hydraulic pressure while using various excavations without using replacement excavation, and perform the construction with low noise and low vibration. be able to. At that time, by using a method as described in Japanese Patent Application No. 2001-290741, it is possible to perform construction in consideration of the environment under construction conditions such as urban areas, rare animal habitats, and the vicinity of precision machine installation facilities.
Further, as represented by the present invention described in (5) above, if a hollow portion is secured in the water and in the ground by excavating the inside of the steel pipe sheet pile, the space can be used, for example, to wash a magnetic sensor or the like. It is also possible to install an excavation monitoring device or the like, and it is also possible to use the inside of the pipe as a multipurpose storage space for storing water or other antifreezing agents.

  According to the present invention described in the above (6), excavation is performed in the construction method, and a hollow steel pipe sheet pile hollow part, a gap formed slightly between the sheet pile and the ground, etc. are filled, so that the wall structure It is possible to increase the robustness of the.

Furthermore, according to the method of said (7) description, since the wall body by a steel pipe sheet pile forms a closed region, it becomes possible to ensure a high protection function.
Therefore, for example, by detecting the foundation part of the existing pier that cannot avoid a decline in bearing capacity in the future by scouring and protecting it from the influence of running water with the structure described in (7) above, it is possible to achieve robust and maintenance at low cost. This makes it possible to provide protection at a low cost.
In addition, since it is possible to take early measures with inexpensive countermeasure costs, the cost of long-term monitoring of the safety of conventional old bridges and the operational safety of old bridges can be reduced. It will be possible to reduce equipment costs and labor costs required for organizational operations to secure the structure usage time management such as regulations and management, etc., and suddenly due to weather conditions such as unexpected flooding Asset management by reducing the significant cost of large-diameter piles to increase the bearing capacity to cope with a significant decline in bearing capacity due to ongoing scouring, increasing the bearing capacity of steel pipe sheet pile foundations, and repairing bridges It is possible to improve the results of
Furthermore, by orderly surrounding with steel pipe sheet piles, by introducing various materials such as rock sludge, chestnut stone, large sandbags to the scoured river bed that have been used as countermeasures, the river bed is covered in a mound shape. Beautify the landscape and environment that have been damaged by the countermeasures that have been carried out, and simultaneously improve the image and preservation of the old structure, which is a cultural heritage that testifies the history of our civil engineering business. The importance of all construction, maintenance and repair processes can be shared with passengers who are users of the structure, that is, the public as a consensus.

  According to the present invention described in (8) above, in the wall structure described above, the steel pipe sheet pile joint portion reaches the support layer of the wall body, so that the wall-like structure is formed in the ground and the foundation. As a result, it is possible to reliably prevent scouring of floating structures by flowing water and suction of sand from the foundation.

  According to the present invention described in the above (8), by providing a gap as a water inlet in a part of the wall body, excessive flowing water is allowed to pass through the rear side of the wall body while utilizing flow resistance. While suppressing resistance, it is also possible to suppress the behavior of running water, which is considered to be the cause of scouring and sucking sand from the foundation.

According to the present invention described in (9) above, not only due to the performance of the wall body 14 by the steel pipe sheet pile 1, but for example, in the construction in a river, it is installed so as to cover a river bed portion that needs protection for the floor protection. Connect the upper end of the steel pipe sheet pile and the structure for floor protection using the rigidity of the steel pipe sheet pile 1 (the socket part is attached to the side of the structure for floor protection). It is possible to insert the steel sheet pile main pipe at the top of the steel pipe sheet pile or the hollow part of the steel pipe sheet pile joint as a socket part. Such a protruding portion can be provided and fitted to the lower end of the floor protection structure, and a firm connection structure can be secured.
In addition, in this way, the artificial rock block can be easily and firmly connected to the upper end of the steel pipe sheet pile to improve the landscape, and by flowing water control such as the shape of the surface of the floor protection structure (for example, provided on the surface) The direction and depth of the ditch) can be devised to control the direction of flowing water that causes scouring, etc. to protect the bridge pier and the river bed exposed to the flowing water, or the water level drops during the drought season and the sand bar It will also be possible to take measures to improve the environment by installing a greening block at the location where it will be, and securing the habitat of aquatic plants such as artificial reefs.

  According to the present invention described in (10) above, in the wall structure, the steel pipe sheet pile main pipe projecting to the ground or the joint part is used, and the rear side of the wall body using the flow resistance. It is possible to secure a water passage through which running water is allowed to pass through at low cost, and the material cost can be reduced by designing in advance a small amount of material that protrudes into the water.

  Further, by providing a screen in the gap according to (11), it becomes possible to prevent the material from filling the back side of the steel pipe sheet pile from flowing out to the front side even if the particle size of the material is reduced. For example, the screen can be provided easily and inexpensively using the structure of the steel pipe sheet pile.

According to the present invention described in the above (13), it is difficult to press-fit with a conventional vibro hammer or press-fitting machine when constructing a wall structure having a gap in a part of the wall made of the steel pipe sheet pile. With the hard ground, down-the-hole hammers can be drilled securely, and steel pipe sheet piles that could only be driven only into soft ground have been cast to the support layer composed of hard ground and rock. As a result, it is possible to firmly secure the wall structure by the steel pipe sheet pile for the purpose of protecting the above-mentioned water structure foundation from the influence of flowing water.
At that time, since the excavation is performed with a diameter smaller than that of the steel pipe sheet pile main, the caking property of the support layer of the original ground is impaired, and it is prevented from being affected by secondary scouring or sand suction. Can do.

  According to the present invention described in the above (17), in the method of using the down-the-hole hammer for placing the steel pipe sheet pile when the wall structure by the steel pipe sheet pile is constructed, the steel pipe sheet pile is press-fitted following the excavation. To impair the caulking properties of the press-fitting boards to hard ground that forms the surface layer that includes hard obstacles such as cobblestones and boulders in the original ground, and to the hard ground and rock that are consolidated to form the support layer It becomes possible to perform placing.

According to the present invention described in (18) above, in the step of press-fitting a steel pipe sheet pile following the excavation of (17), the excavation diameter is arbitrarily secured according to the solidity of the ground, the hardness of the rock mass, and the like. Therefore, for hard ground that is relatively easy to penetrate, steel pipes are drilled with a down-the-hole hammer drill bit with a small diameter (same diameter as steel pipe sheet pile, approximately the same diameter as the steel pipe sheet pile) to protect the solid ground. In the bedrock layer, which allows the raw ground to be further compacted by consolidation hardening when the sheet pile penetrates, there is a concern that the penetration resistance will increase, and the caking property after excavation can be expected sufficiently. It is possible to select a rapid construction by performing construction with a diameter substantially larger than the steel pipe sheet pile main pipe.
As a result, it is often required to complete the construction within the dry season of the river, and there is a restriction that the construction must be carried out during the dry season, optimized for the characteristics of this technical field in Japan. It is possible to select a method corresponding to rapid construction when maintaining and repairing bridges where restrictions due to construction conditions with many obstacles such as sky head limitation of reinforcement of objects and construction close to existing structures occur. In addition to being able to operate widely in normal times, it is also possible to respond to rapid construction aimed at preventing unforeseen and urgent disasters such as damage caused by typhoons or earthquakes.
In addition, since the selection as described above can be performed, it is possible to select an optimum diameter for performing construction at as low a cost as possible when utilizing characteristics of various raw grounds having many uncertain factors.

  According to the present invention described in the above (19), the impossibility of intrusion of the joint part, which causes the largest construction failure in the press-fitting of the steel pipe sheet pile, is reduced without impairing the solidity of the original ground which is the object of the present invention. As a result, the steel pipe sheet pile can be pressed into the hard ground and the rock more reliably.

  Hereinafter, specific embodiments of the present invention will be described in detail.

[Protective structure of water structure foundation on hard ground]
First, based on FIGS. 1-5, the outline | summary of the protection structure of the water structure foundation on a hard ground is demonstrated.

FIG. 1 which shows a prior art is a temporary deadline by the steel pipe sheet pile 1 and the steel sheet pile 5 at the time of the construction of the underwater structure which takes a support layer in the conventional soft layer, and the well foundation constructed in the ground as a permanent structure. It is a general cross section when construction is performed.
FIG. 2 showing the prior art shows a cross section of a steel pipe sheet pile by an all casing or ground auger for hard ground that is not shown in advance when the base is composed of hard ground or rock 3 among the conventional methods. The steel pipe sheet pile 1 and the steel sheet pile 5 are driven after the replacement excavation having a diameter larger than the circumference including the steel pipe, and the wall body 11 made of the steel pipe sheet pile 1 and the wall body 12 made of the steel sheet pile 5 are driven. The situation of the plane and cross section which are shown is illustrated.

  In the conventional method, the replacement part is performed in a large range so that the wall 11 and the wall 12 can be seen, and the front surface of the walls 11 and 12 formed by the steel pipe sheet pile 1 and (particularly) the steel sheet pile 5, that is, the flowing water 13. However, since the existing replacement part is large in the part that hits the wall, at least the solidity of the original ground is lost, and as a result, loosening that causes secondary scouring has occurred.

In the present invention, as shown in FIG. 3, first, the excavation is performed with a smaller diameter than the outer diameter of the main pipe sheet pile main pipe, utilizing the characteristic of being a tubular pile having a hollow steel sheet pile.
At that time, as is generally done, it is possible to provide a replacement section 15 made of high-quality soil by replacement excavation by an all-casing construction for hard ground, and to provide an excavation apparatus according to the embodiment of FIG. By using the apparatus as shown in FIG. 15 with the above configuration, the steel pipe sheet pile press-fitting work may be followed by the excavation work and may be simultaneously advanced.
In addition, when a large penetration resistance occurs, a replacement part 15 ′ can be provided at the joint placement position, and the main pipe replacement part 15 and the joint part replacement part 15 ′ are used according to the soil properties. Steel pipe sheet pile can be pressed.

  Then, if the steel pipe sheet pile 1 is driven into the original ground using, for example, a well-known hydraulic press machine, it is press-fitted into the ground having high caking property or high penetration resistance including many hard obstacles such as cobblestones and rolling stones. The steel pipe sheet pile is necessary for the original ground because there is room for the earth and sand pushed away by the press-fitting of the steel pipe sheet pile 1 to the already-placed replacement portion 15 provided in the hollow portion of the steel pipe sheet pile. It becomes possible to penetrate into the ground without impairing the ligation property, and the rigid wall body 14 can be configured.

  Such a method cannot be achieved with a plate-like structure having no hollow portion, such as the steel sheet pile 5 that has been widely used for scouring prevention in the past, and the existing replacement portion is generated on the outer wall side where the running water hits. Therefore, secondary scouring occurred there, and as a result, the countermeasures against running water had to be an emergency measure.

  Furthermore, the wall body 14 by the said steel pipe sheet pile 1 is the wall body which has the well cross section 14 'which forms the closed area | region which surrounds a structure foundation part in a well state like the conventional steel pipe sheet pile well foundation and the temporary deadline by a steel pipe sheet pile. The robustness can be ensured.

  When surrounding the structure base, the well cross section 14 ′ itself formed by the steel pipe sheet pile wall body is used as the outer shell 16, and the outer shell having a space inside the well cross section 14 ′ formed by the steel pipe sheet pile wall body. It is possible to choose by design to surround a structure foundation such as 17.

With such a structure, the caisson 21 that forms the footing base of the existing old pier 18 that is constructed without being sufficiently penetrated into the hard ground and the rock mass 9 (the position on the inner side of the ground contact with the ground surface) A leveling concrete 20 is placed on the bottom surface of the steel plate, and a footing concrete 19 is placed on the upper surface thereof). Unlike conventional protective measures, the surroundings of the caisson 21 are surrounded by the wall body 14 having sufficient strength, and the wall 14 is scoured by taking advantage of the inherent strength of the rock layer 9 which is the hard ground as the supporting layer. Take preventive measures such as permanent scouring by taking measures such as placing concrete in the area, and avoiding the increase in the volume hindrance of the prior art (caused by inputs such as rock sludge 23) Impaired river environment along with it, can be obtained an excellent effect that it is possible to protect the landscape.
Furthermore, after the steel pipe sheet pile wall 15 has been cast from the water, the projecting portion 25 on the ground of the steel pipe sheet pile is cut by a known steel pipe cutting machine, and then the river bed where future scouring is a concern is covered. When installing the floor protection structures 26, 26 ′, expecting the rigidity of the steel pipe sheet pile 1 and the steel pipe sheet pile wall 15, the projecting steel pipe sheet pile upper end is connected to the floor protection structure (for floor protection). A socket part is provided on the structure side to fit the tip of the sheet pile, and the lower part of the floor structure is rolled in and integrated by concrete placement, fastened with bolts and nuts, etc.) and the steel pipe sheet pile main pipe at the upper end of the steel pipe sheet pile Alternatively, a hollow portion of the steel pipe sheet pile joint portion can be used as a socket portion, and a projection 26 that can be inserted into the socket portion is provided at the lower end of the floor protection structure to be fitted, and so on. Solid use of the interior Coupling structure is to be secured.
In addition, the inner space of the steel pipe sheet pile 1 can be widely used as a space for storing devices necessary for the river monitoring system, such as attachment of a magnetic sensor for measuring the river bed state.

  Further, this wall body 14 uses a flow resistance by providing a water passage opening 28 on a steel pipe sheet pile and projecting on the ground, and thus providing a water-permeable opening in a part of the steel pipe sheet pile 1 projecting into the water 4. In addition, it is possible to secure a water passage through which the running water is passed to the rear side of the wall body at a low cost, and in addition, a portion of the steel pipe sheet pile main pipe part 2 and the steel pipe sheet pile joint part 3 that is not lined up (steel pipe sheet pile). By adopting a structure having the portion 29 lacking the main pipe and the portion 30) lacking the joint portion, the cost of the material can be reduced by designing in advance a portion that protrudes into the water.

  Furthermore, by covering the gaps 28, 29, and 30 with the network structure 31 and providing a screen, even if a filler having a small particle size such as a crusher run is put on the back surface of the steel pipe sheet pile, it is prevented from flowing out. In addition, a fitting portion is provided at the end of the net-like structure, and it is secured by fitting with a steel pipe sheet pile joint at the end of the plate-like insertion screen 32. By using the structure of having a joint part (for example, an LL joint 3 ′), if the steel pipe sheet pile is inserted from the upper surface after the steel pipe sheet pile driving is completed, a structure in which the screen is provided easily and inexpensively can be obtained.

[Method of constructing protective structure for floating structure foundation on hard ground]
Then, the construction method of the protection structure of the floating structure foundation on the hard ground is described.

  In constructing a wall body made of steel pipe sheet piles 14 on such a hard ground, when the steel pipe sheet pile constituting the wall body is placed, the hard ground 9 is replaced with the previous replacement parts 15, 15 '. When performing excavation, according to the present invention, by using the down-the-hole hammer using the method as shown in FIGS. 14 and 15, the hard ground can be reliably excavated, and the excavation and press fitting of the steel pipe sheet pile can be performed. Can proceed in parallel.

The aspect is as follows.
An excavator comprising a down-the-hole hammer 35, an excavation shaft member 34 mounted on the tip thereof, and a rotary drive device 33 for rotating the excavation shaft member 34, and a steel pipe sheet pile 1 mounted on the outer side of the excavation shaft member 33 are used for maintenance and repair work of existing piers. It is suspended by a crawler crane 37 on a construction road for accessing the inside of the river for carrying out and a work gantry for subsequent work such as steel sheet pile driving.

A compressor 39 that generates compressed air for driving the down-the-hole hammer 35 and an engine generator that is a power source of the rotary drive device are installed in the back. The compressed air generated by the compressor 39 is collected in a receiver tank, and a lubricating oil supply device Further, the hammer lubricating oil is appropriately injected through the rotary drive device 33 through the high pressure air hose, the inside of the excavation shaft member 34, and supplied to the down-the-hole hammer 35 for excavation.
A guide material 43 is provided in advance at the pile core position in the river so that the steel pipe sheet pile 1 can be placed at the design position, and the crawler crane 37 hangs the excavator at the design position secured by the guide material 43. Then, excavation by the down-the-hole hammer 35 and placement of steel pipe sheet piles are performed.

  When placing the steel pipe sheet pile 1, according to the method described in Japanese Patent Application No. 2000-157847, 1) Before the steel pipe sheet pile 1 is placed, the replacement parts 15 and 15 'are provided, and then the steel pipe sheet pile is press-fitted. 2) The steel pipe sheet pile 1 can be pressed and excavated at the same time.

  That is, in the excavation using the down-the-hole hammer 35, the inner end of the pipes having the inner space such as the hole wall protection pipe or the steel pipe sheet pile 1 is formed in the inner space so that the hammer is advanced with the progress of the hammering crushing. A stepped portion 47 is provided on the upper portion of the excavating bit 44 of the down-the-hole hammer 35, and a stepped portion 45 is provided so as to protrude toward the inner wall of the steel pipe, and the down-the-hole hammer is inserted into the steel sheet pile main pipe 2. When drilling the down-the-hole hammer 35, the step 45 of the drill bit 44 and the step of the pipes interfere with each other when the drilling device sinks with the progress of the drilling by hitting crushing, and the direction of the drilling It can be press-fitted following excavation.

By such a method, especially pipes are made of steel pipe sheet pile 1, excavation and press fitting process of steel pipe sheet pile can be made parallel to the original ground composed of hard ground or rock, Speedy construction corresponding to rapid construction at the time of internal construction and disaster recovery can be implemented.
Furthermore, the machine configuration shown in FIGS. 14 and 15 can also be used for preceding excavation of the joint portion. In this case, the excavation bit, the hole wall protection pipe, etc., reduce the excavation amount near the joint portion as much as possible. Thus, it is possible to prepare a device with a diameter that is almost the same as the joint pipe diameter, a diameter that is substantially less than or equal to the pipe diameter, and a diameter that encompasses the entire fitting fitting part, and can be constructed in the same way as the main pipe. It is.
Further, at that time, the joint part and the main part excavation may be performed in parallel.

  Further, when the press fitting of the steel pipe sheet pile 1 and the excavation work are performed simultaneously, the outer circumference forming the drilling surface of the excavation bit 44 is substantially the same diameter as the steel pipe sheet pile main pipe 2 diameter 46 ', and the diameter is substantially less than 46, or about 46 ″, which is approximately equal in diameter, can be configured to be expanded so that for hard ground 9 which is relatively easy to penetrate, In order to protect the caulking properties, drilling with a drill bit of a down-the-hole hammer with a small diameter (same diameter 46 'as the steel pipe sheet pile, approximately 46), and further compacting the original ground by consolidation hardening when the steel pipe sheet pile penetrates In the bedrock layer, where there is a concern that the penetration resistance will increase and the caking property after excavation can be expected sufficiently, the workability is emphasized, and the diameter is 46 ”which is substantially larger than the steel pipe sheet pile main pipe. Construction Carried out, it is possible to select the rapid construction.

  In addition, depending on the ground to be excavated, it is possible to perform construction with a hydraulic press machine in order to perform low noise and low vibration construction. When discharging excavation shear using the section as a soil discharge path, the excavation shear is intermittently made using a soil removal device (for example, a screw driver (medium excavation device) 49 as shown in FIG. 17) having a excavation storage unit. To raise.

  The screw driver 49 shown in FIG. 3 is suspended by a crane hook 56 via a wire rope, and includes a screw drill 51, a rotation drive device 53, a hollow cylindrical capsule pipe 52, and a telescopic cylinder 51 for screw drill. ', A hydraulic gripper 54, and a telescopic cylinder 55 for gripper.

  In the screw driver 49, the screw drill 51 includes a drill head 50 for excavating the ground at the tip thereof, and is connected to a rotation driving device 53 for driving the screw drill 51 to rotate. The capsule pipe 52 is provided so as to cover the periphery of the screw drill 51, and is configured to be able to temporarily store the excavation shear excavated by the screw drill 51 inside.

The screw drill telescopic cylinder 51 ′ is connected to the screw drill 51 and is configured to be telescopic so that the screw drill 51 can be moved up and down freely. The hydraulic gripper 54 can secure a rotational press-fitting reaction force necessary for the rotary press-fitting excavation with respect to the inner wall of the steel pipe sheet pile main pipe 2 in the overhanging state. The gripper telescopic cylinder 55 is connected to the hydraulic gripper 52 and is configured to be telescopic so that the hydraulic gripper 52 can be freely extended.
If the inside of the steel pipe sheet pile is excavated and a hollow portion is secured in the water and in the ground, it is possible to use the space to install, for example, a scour monitoring device 57 such as a magnetic sensor. It is also possible to use the inside of the pipe as a multipurpose storage space such as the water storage 58 and other antifreeze agents.

Finally, when the steel pipe sheet pile 1 is driven, as shown in FIG. 18, when the excavation is used together, the tip portion of the steel pipe sheet pile 1 is filled with a concrete material, and the closed state 57 is formed inside and outside the steel pipe sheet pile. It can be ensured, and the influence of flowing water such as scouring can be reduced by preventing water loss. Moreover, in order to ensure high quality, it is also possible to inject chemicals into the surrounding ground.
The top position of the cast steel sheet pile can be freely selected, and it can be designed freely according to the structural requirements given to the steel sheet pile other than scouring prevention. The construction procedure such as using the steel pipe sheet pile wall 15 as a temporary cut-off work for water stop around the structure during construction reinforcement and new substructure construction can be arbitrarily selected in design.

[Other Embodiments]
1. Scouring Mechanism Based on FIG. 19, the scouring mechanism expected when a conventional steel pipe sheet pile is placed on the bottom of the water will be described.

  When the steel pipe sheet pile is driven on the bottom of the ground, the flowing water from the upstream hits the front surface of the steel pipe sheet pile, and a downward flow along the cylinder occurs. This downward flow generates a rotational flow (vortex) as shown in FIG. 18 on the ground in front of the steel pipe sheet pile. The swirling rotating flow picks up sand from the riverbed that touches it and lowers the riverbed level. When the river bed is lowered, the vortex position is lowered accordingly, so that the river bed ahead of the steel pipe sheet pile is scoured with time.

2. Next, based on FIG. 20, the pile material of the present invention having a scouring prevention function will be described. Hereinafter, a steel pipe sheet pile is mentioned as an example of a pile material.

  As shown in FIG. 20, a steel pipe sheet pile as an example of a pile material includes a main pipe made of a steel pipe, two joints fixed to the main pipe, and a plate for controlling the water flow around the steel pipe sheet pile (water flow). Control means). When connecting a steel pipe sheet pile to an adjacent steel pipe sheet pile, a joint of each steel pipe sheet pile is slidably engaged with each other. As shown in FIG. 20 (B), the plate constituting the water flow control means is formed in a bowl shape projecting around the steel pipe sheet pile. The bowl-like plate blocks the downward water flow along the outer wall of the steel pipe sheet pile and prevents the generation of a rotating flow that is a cause of scouring. Therefore, the steel pipe sheet pile can be protected from the influence of flowing water.

  Note that the number of bowl-shaped plates is not necessarily limited to one, and a plurality of bowl-shaped plates may be provided as shown in FIGS. Moreover, the structure of a water flow control means is not limited to a bowl-shaped plate, The convex-shaped member (for example, block-shaped member) protruded from the outer wall of a pile material may be sufficient. Moreover, it is also possible to process a part of the outer wall of the main pipe sheet pile into an irregular shape as shown in FIG. 22 so that the outer wall functions as water flow control means.

  Further, in order to prevent a rotating flow from being generated in front of the steel pipe sheet pile, the steel pipe sheet pile can be configured as shown in FIGS. In FIG. 23, the water pipe opening is formed in the main pipe of the steel pipe sheet pile. Moreover, in FIG. 24, the slit which can permeate | transmit water is formed in the main pipe of a steel pipe sheet pile. Such openings and slits may be formed in the joint.

3. Next, a wall structure using the above-described steel pipe sheet pile will be described with reference to FIGS. 25 to 28.

  The wall shown in FIG. 25 is configured by connecting a plurality of steel pipe sheet piles. Each steel pipe sheet pile has the scour prevention function described with reference to FIGS. The wall body which consists of a some steel pipe sheet pile is constructed facing this water structure foundation part so that the water flow which goes to a water structure foundation part (it shows by hatching) may be interrupted | blocked.

  The plurality of steel pipe sheet piles constituting the wall body are arranged so as to draw a substantially V-shape or a parabola as viewed from above. Examples of the V-shaped arrangement of the wall structure are shown in FIGS. Moreover, the parabolic arrangement | positioning example of a wall structure is shown to FIG.26 (D)-(F). The steel pipe sheet pile located at the top (upstream end) of the V-shaped arrangement shown in FIG. 25 is located upstream of the other pile materials. Moreover, a water structure foundation part is located downstream from the steel pipe sheet pile of a top part, and is located inside a wall body. According to such a wall structure, the foundation of the floating structure can be protected from the influence of flowing water.

  In addition, in order to protect a foundation part more reliably from the influence of flowing water, as shown in FIG. 27, it is preferable to construct | assemble a wall body so that the circumference | surroundings of a water structure foundation part may be enclosed. In addition, in a river or the like, when the water flow direction is not fixed in one direction, it is preferable to construct the wall body as shown in FIG.

  As described above, the present invention is suitably used in the technical field of ensuring soundness in the new construction of water structures in general and repairing and refreshing existing structures. In particular, rivers with an old history such as railway bridges are used. By protecting the structure and its supporting ground, beautifying the river, and promoting environmental measures, the structure is secured and disaster prevention measures are strengthened, and the historical value of civil engineering structures in Japan is a cultural heritage. It can be widely used as a means to be passed on to future generations.

It is the plane and cross section of the wall body constructed | assembled by the steel sheet pile used for the temporary cutoff of the conventional water structure foundation, etc., and a steel pipe sheet pile. It is the plane and cross section of the wall body constructed | assembled after substitution excavation in the hard ground with the steel sheet pile used for the temporary cutoff of the conventional water structure foundation, etc., and a steel pipe sheet pile. A plane that penetrates the support part of the wall body into the solid ground formed from either hard ground solidified or rock, without excavation with a diameter larger than the circumference encompassing the cross section of the steel pipe sheet pile And a cross section. Without digging ahead with a diameter larger than the circumference encompassing the steel pipe sheet pile cross section, when penetrating the support portion of the wall body into the solid ground formed from either solid hard rock or rock mass, It is a plane which uses joint excavation of a joint part together. It is the top view which instruct | indicated planar separation of the wall body comprised with the outline of a structure base part, and a steel pipe sheet pile. It is the cross section of the case where it protects with the steel pipe sheet pile, and the cross section of the common caisson basic protective measure by a prior art. Cross section of general caisson basic protective measures by conventional technology and when projecting it with steel pipe sheet pile, cut the protruding part of the wall body by steel pipe sheet pile and cover the above wall body and river bed existing in the ground It is the figure which connected the protective floor structure to do. It is the figure which instruct | indicated the aspect which penetrates a joint part in the ground in the steel pipe sheet pile wall body which uses a hard ground as a support layer. It is the plane and cross section which provided the hole which can permeate | transmit water in a steel pipe sheet pile. It is the plane and cross section which made water flow freely by missing one row of steel pipe sheet piles. It is the plane and cross section which made water flow freely by notching the joint part of a steel pipe sheet pile. It is the cross section of the state which coat | covered the water flow opening provided in the steel pipe sheet pile wall body freely, and this water flow opening was covered with the network structure. It is the cross section which fitted the network structure which has a steel pipe sheet pile joint part and an end part which can be freely fitted, and this network structure with the joint part. It is the aspect of a machine structure at the time of press-fitting a steel pipe sheet pile simultaneously with excavation using a down-the-hole hammer. It is a cross section which instruct | indicates the aspect of the excavation bit at the time of press-fitting a steel pipe sheet pile simultaneously with excavation using a down-the-hole hammer. It is the aspect of the cross section which excavates a steel pipe sheet pile joint part ahead. It is an example of the digging apparatus which excavates the inside of a steel pipe sheet pile with low noise and low vibration. It is the aspect which inject | pours a root hardening material into the underground penetration part of a steel pipe sheet pile. It is a figure which shows the mechanism of scouring. It is a figure which shows the pile material which concerns on this invention (a steel pipe sheet pile is shown as an example), Comprising: FIG. 20 (A) is a front view, FIG.20 (B) is a top view. It is a figure which shows the modification of the pile material shown in FIG. It is a figure which shows the modification of the pile material shown in FIG. It is a figure which shows other embodiment of the pile material which concerns on this invention (a steel pipe sheet pile is shown as an example). FIG. 24A is a front view and FIG. 24B is a top view showing another embodiment of a pile material according to the present invention (a steel pipe sheet pile is shown as an example). It is a top view which shows the example of arrangement | positioning of the wall structure which concerns on this invention. It is a top view which shows the example of arrangement | positioning of the wall structure which concerns on this invention. It is a top view which shows the example of arrangement | positioning of the wall structure which concerns on this invention. It is a top view which shows the example of arrangement | positioning of the wall structure which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel pipe sheet pile 2 Steel pipe sheet pile main pipe 3 Steel pipe sheet pile joint part 4 Wall body by conventional steel pipe sheet pile 5 Steel sheet pile 6 Wall body by steel sheet pile 7 Underwater 8 Surface layer 8 'boulders and rolling stones that do not contain hard obstacles such as cobblestones and rolling stones Surface layer including hard obstacles such as 9 Hard ground and rock mass 10 Pre-excavation part that has been replaced by replacement excavation 11 Wall body made of steel pipe sheet pile placed in the replacement part 12 By steel sheet pile cast in the replacement part Wall body 14 Steel pipe sheet piles placed on the ground having the replaced part smaller in diameter than the main pipe sheet pile
According to the wall 15 The preceding excavation part 15 'of a smaller diameter than the steel pipe sheet pile main pipe The preceding excavation part 16 of the steel pipe sheet pile joint part The structure base part 17 having a wall inwardly separated from the steel pipe sheet pile well Structure foundation 18 with sheet piles as wall surface Existing pier 19 Footing concrete 20 Leveling concrete 21 Caisson foundation 22 Scouring section 23 Rubble (rock sludge) mound 24 provided as an emergency measure 25 Rock shear 25 Cutting section 26 of steel pipe sheet pile Protective floor structure 27 Steel pipe sheet pile joint part penetrated to the support layer part in the ground 28 Water inlet port provided in the steel pipe sheet pile 29 Water inlet part provided with one steel pipe sheet pile main pipe missing One row of steel pipe sheet pile joint parts Water flow port 31 provided to cover the water flow port 32 Plate-like network structure that can be fitted to a joint portion of a steel pipe sheet pile 33 Rotation drive device 34 Excavation shaft member 35 Down-the-hole hammer 36 Digging Bit 37 Crawler crane 38 Motor generator 39 Air compressor 40 Receiver tank 41 Line oiler 42 Pier 43 Guide material 44 Drilling bit detailed view 45 Drilling bit step 46 Drilling bit tip 47 Steel pipe sheet pile step 48 Including two joints Joint section leading excavation 48 ′ having a sectional diameter of a joint section leading section excavation 48 ′ including a joint section Joint section leading excavation of a section diameter included in one joint section 49 Screw driver drilling device 50 Screw Head 51 Screw drill 51 'Expansion cylinder for screw drill 52 Capsule pipe 53 Press-fit cylinder 54 Hydraulic gripper 55 Telescopic cylinder for gripper 56 Hook 57 Magnetic sensor 58 for scouring monitoring Water, other fluid 59 Rooting material injection part

Claims (5)

The foundations of water structures such as direct foundations and caisson foundations that are supported by shallow parts of the riverbed that are so hard that a pile material cannot be penetrated by a vibratory hammer or hydraulic press machine are washed by running river water. In a method to protect against digging,
A step is provided on the inner wall of the pile material made of steel pipe sheet piles,
A step is provided at the top of the drill bit of the down-the-hole hammer,
Set the pile material at the planned pile material placement position on the raw ground,
Insert the down-the-hole hammer into the pile material, perform excavation with the down-the-hole hammer,
When the down-the-hole hammer settle in drilling drilling in the, and the step portion of the down-the-hole hammer side and pile material side is interference in the vertical direction, whereby, due to the striking force to follow the strike breaking by the hammer Make sure that the pile material is pressed in the direction of excavation,
The pile material is driven so as to be supported by the original ground by the excavation and hammering ,
By repeating the placing process of the pile material, a wall body formed by connecting adjacent pile materials is constructed so as to face the water structure foundation.
A method for protecting the foundation of a floating structure characterized by the above.   The water structure according to claim 1, wherein a wall body formed by connecting adjacent pile materials is constructed so as to surround the periphery of the water structure foundation by repeating the pile material placing step. How to protect the foundation of objects.   The method for protecting a water structure foundation according to claim 1, wherein the wall is constructed so as to face the water structure foundation so as to block a water flow toward the water structure foundation. Positioning all or a part of the plurality of pile members constituting the wall body so as to draw a substantially V-shaped or parabola when viewed from above,
The pile material located at the top of the substantially V-shaped arrangement or the parabolic arrangement is positioned upstream of the other pile materials,
Constructing the wall so that the water structure foundation is located downstream of the pile material at the top,
The method for protecting a water structure foundation according to claim 1.   The method for protecting a water structure foundation according to claim 1, wherein the pile material is placed on the raw ground planned to be piled without performing a preceding excavation excavation.

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