JP5435499B2 - Steel pipe pile connection structure - Google Patents

Description

  The present invention relates to a steel pipe pile connection structure that is used to connect a lower end portion of an upper pile body to an upper end portion of a lower pile body in a steel pipe pile or to connect an excavation head to a lower end portion of a pile body.

  Steel pipe piles used for the foundations of buildings, etc., are bottom-up types with spiral wings provided on the excavation head attached to the lower end of the pile body, and multi-blade types with spiral wings provided in the intermediate required part of the pile body together with the excavation head In addition, three types of straight steel pipe piles with only a drilling head attached to the lower end of the pile body are generally known, but any of these steel pipe piles is limited in pile length by the pile driving machine, The maximum length is 6 to 8m due to restrictions due to the storage space and the length during transportation. For piles with a length exceeding this, a pile with a predetermined length consisting only of the pile body without the excavation head It is designed to be used with successive additions while driving into the ground. When driving steel pipe piles with pile driving machines in soft ground, the required number of piles are added successively until the pile tip reaches the support layer, that is, the lower end of the following pile is added to the upper end of the pile that has been driven first. In this connection, conventionally, the lower end of the subsequent pile is connected to the upper end of the preceding pile by welding. However, such steel pipe pile extension work by such welding work requires a power source and a generator for welding, which increases costs, and can not be performed because it may cause electric shock in rainy weather. Furthermore, there is a problem that the cost is high because a welding engineer skilled to some extent is necessary for welding.

  In order to solve the above problems, the applicant of the present invention has proposed a steel pipe pile connection structure as described in the following cited document. When connecting the lower end of the upper pile body to the upper end of the lower pile body, the lower half of the steel pipe pile is fitted into the upper end of the lower pile body and the upper half is A cylindrical connecting member fitted inside the lower end of the pile body is provided, and bolt insertion holes are provided at regular intervals in the circumferential direction at the upper end of the lower pile body and the lower end of the upper pile body. On the upper end side and the lower end side, a bolt insertion hole is provided at a position that matches the pile main body side bolt insertion hole when the connection member is internally fitted to the connection end of the pile main body, and the inner peripheral surface side of the connection member Is provided with a nut holding portion for holding the nut at a position opposed to each connecting member side bolt insertion hole in the axial direction, and the lower half of the connecting member is fitted into the upper end of the lower pile body, Insert the bolt from the pile body side bolt insertion hole into the connecting member side bolt insertion hole and into the nut holder The connecting member is fixed to the upper end of the lower pile body by screwing the held nut, the upper half of the connecting member is fitted into the lower end of the upper pile body, and the bolt is connected to the pile main body side. The connecting member is fixed to the lower end of the upper pile body by inserting the bolt insertion hole from the bolt insertion hole into the connecting member side bolt insertion hole and screwing into the nut held in the nut holding portion, so that both pile main bodies are integrated. They are connected.

  This connection structure eliminates the need for equipment such as a welding power source and a generator, unlike the conventional connection work by welding, and the connection work does not require skill like welding, thus reducing the work cost. In addition to being able to plan, it is possible to shorten the pile driving construction period.

JP 2010-127029 A

  In the steel pipe pile connection structure described in Patent Document 1, a nut is inserted into each nut holding portion of the connection member prior to the connection work of the pile body by the connection member, but the connection member remains in an upright state. If there is, the nut will not come out from the upper side of the nut holding part, but it will come out when the connecting member is turned sideways or upside down, so a pin hole is provided on the upper end side of one arm wall However, it is necessary to prevent the nut from coming out by inserting a retaining pin into the nut holding part. However, it takes time to insert the retaining pin into the pin hole after inserting the nut into each nut holding part. There is a problem. Moreover, in this connection structure, since the inlet of the upper end side nut holding part and the inlet of the lower end side nut holding part of the connecting member are formed in the same upward direction, the nut is inserted into the lower end side nut holding part. It is difficult to do and takes time.

  In the present invention, in view of the above problems, it is necessary to integrally insert a retaining pin into the nut holding portion as in the prior art by integrally providing a retaining arm capable of inserting a nut in each nut holding portion. In addition, a nut holding part with an inlet facing upward is provided on the upper end side of the connecting member, and a nut holding part with an inlet facing downward is provided on the lower end side of the connecting member so that the nut can be easily inserted. It aims at providing the connection structure of the made steel pipe pile. In addition, the steel pipe pile connection structure according to the present invention is a steel pipe pile manufactured in addition to the connection structure between pile bodies when a required number of piles are successively added until the pile tip reaches the support layer. In doing so, a pile body of one steel pipe pile is divided into a plurality of parts, and a connection structure in the case of connecting the halves is also included.

  Means for solving the above problems will be described with reference numerals in the embodiments described later. The connection structure of the steel pipe pile of the invention according to claim 1 is an upper pile at the upper end of the lower pile body 1. In connecting the lower end of the main body 1, a cylindrical connecting member N in which the lower half is internally fitted to the upper end of the lower pile body 1 and the upper half is internally fitted to the lower end of the upper pile body 1 Bolt insertion holes 7 are provided in the upper end portion of the lower pile body 1 and the lower end portion of the upper pile body 1 at regular intervals in the circumferential direction, and the upper end portion side and the lower end portion side of the connecting member N are connected to each other. A bolt insertion hole 8 is provided at a position that matches the pile main body side bolt insertion hole 7 when the member N is internally fitted to the connection end portion of the pile main body 1, and the upper and lower end portions of the inner peripheral surface of the connection member N are provided. Is a nut holder that holds the nut 10 at a position facing each connecting member side bolt insertion hole 8 in the axial direction. Each of the nut holding portions 9 on the upper end side is provided with a pair of holding walls 11 and 11 on both sides for restricting rotation of the nut 10 by receiving the nut 10 inserted from the upper inlet O at the opposite position. In order to prevent the nut 10 from coming out of the O and to hold the nut 10 in the opposite position, it is integrally projected on the holding wall 11 on one side so as to narrow the inlet O, and the nut 10 is inserted when the nut is inserted. Each of the nut holding portions 9 on the lower end side includes a retaining arm 12 that elastically deforms to widen the inlet O by being struck from the inlet O and permits insertion, and is restored after insertion to prevent the nut 10 from coming off. Is formed symmetrically with the nut holding portions 9 on the upper end side, and the lower half of the connecting member N is fitted into the upper end of the lower pile body 1 so that the bolt 13 is connected to the pile body. From side bolt insertion hole 7 The connecting member N is fixed to the upper end of the lower pile body 1 by being inserted into the connecting member side bolt insertion hole 8 and screwed into the nut 10 held in the nut holding portion 9. The nut 10 is internally fitted to the lower end of the upper pile body 1, and the bolt 13 is inserted from the pile body side bolt insertion hole 7 through the connecting member side bolt insertion hole 8 to the nut 10 held by the nut holding portion 9. By screwing, the connecting member N is fixed to the lower end of the upper pile body 1 and the pile bodies 1 and 1 are integrally connected.

  According to a second aspect of the present invention, in the steel pipe pile connecting structure according to the first aspect, the retaining arm 12 of each nut holding portion 9 is opposed to the holding wall 11 on the opposite side from the upper end on the near side of the holding wall 11 on one side. It is characterized by comprising an arm main body part 12a projecting horizontally toward the part and a projecting part 12b projecting integrally so as to slightly narrow the inlet O of the nut holding part 9 from the inner surface of the tip end part of the arm main body part 12a. To do.

  Claim 3 is the steel pipe pile connection structure according to claim 1 or 2, wherein each holding wall 11 of each nut holding part 9 has a substantially L-shaped vertical wall part 11a and a vertical wall part 11a in plan view. And a nut receiving wall portion 11b protruding inwardly from the lower end portion.

  A fourth aspect of the present invention is the steel pipe pile connection structure according to any one of the first to third aspects, wherein the back surface portion of the nut holding portion 9 is a pressure contact surface that is pressed by tightening a bolt 13 screwed into the nut 10. Reference numeral 14 denotes a flat portion.

  Claim 5 is the steel pipe pile connection structure according to any one of claims 1 to 4, wherein the connecting member N has an outer circumferential surface in the longitudinal direction of the steel pipe when the pile body 1 to be connected is an electric resistance steel pipe. The groove 15 for receiving the weld bead 22 that extends and protrudes toward the inner peripheral surface is provided in the connecting member axial direction.

  According to a sixth aspect of the present invention, in the steel pipe pile connection structure according to the fifth aspect, the connecting member side bolt insertion hole 8 is provided at a position equidistant from the concave groove portion 15 in the circumferential direction of the connecting member. At the same time, the pile body 1 has seven pile body side bolt insertion holes at the equidistant position n in the circumferential direction of the pile body from the weld bead 22 to the left and right.

  The connection structure of the steel pipe pile according to any one of claims 1 to 6, wherein the connection member N is divided into two equal parts in the vertical direction, as illustrated in FIGS. Two halved wax models Wn having the same shape as the halved body are molded from a wax model mold, and both halved wax models Wn and Wn are joined symmetrically in the vertical direction to connect to the connecting member N in the same shape. A member wax model WN is formed and cast by the lost wax method using the connecting member wax model WN.

  The connection structure of the steel pipe pile of the invention which concerns on Claim 8 is a cylindrical shape which has the same outer diameter as the outer diameter of the pile main body 1 in connecting the lower end part of the upper pile main body 1 to the upper end part of the lower pile main body 1. Upper and lower base tube portions 21 and 21 to which the lower end portion of the upper pile body 1 and the upper end portion of the lower pile body 1 are externally fitted to the upper and lower ends of the main body 20, respectively. A cylindrical connecting member M is formed, and bolt insertion holes 7 are provided in the upper end portion of the lower pile body 1 and the lower end portion of the upper pile body 1 at regular intervals in the circumferential direction. Each of the upper and lower base tube portions 21 is provided with a bolt insertion hole 8 at a position that matches the pile body side bolt insertion hole when the connecting end portion of the pile body 1 is externally fitted to the base tube portion 21. 21 is a nut holder that holds the nut 10 at a position opposed to each base tube portion side bolt insertion hole 8 in the axial direction. Each of the nut holding portions 9 on the upper end side is provided with a pair of holding walls 11 and 11 on both sides for restricting rotation of the nut 10 by receiving the nut 10 inserted from the upper inlet O at the opposite position. In order to prevent the nut 10 from coming out of the O and to hold the nut 10 in the opposite position, it is integrally projected on the holding wall 11 on one side so as to narrow the inlet O, and the nut 10 is inserted when the nut is inserted. Each of the nut holding portions 9 on the lower end side includes a retaining arm 12 that elastically deforms to widen the inlet O by being struck from the inlet O and permits insertion, and is restored after insertion to prevent the nut 10 from coming off. Is formed symmetrically with the nut holding portions 9 on the upper end side, and the lower base tube portion 21 is fitted into the upper end portion of the lower pile body 1 so that the bolt 13 is connected to the pile body side. From the bolt insertion hole 7 to the base tube The lower base tube portion 21 is fixed to the upper end of the lower pile body by being inserted into the side bolt insertion hole 8 and screwed into the nut 10 held in the nut holding portion 9, and the upper base tube portion 21 is moved upward. The bolt 13 is inserted into the lower end portion of the pile body from the bolt body side bolt insertion hole 7 through the base tube portion side bolt insertion hole 8 and screwed into the nut 10 held in the nut holding portion 9. Thus, the upper base cylinder portion 21 is fixed to the upper lower end portion of the pile main body, and the two pile main bodies 1 and 1 are integrally connected.

  According to a ninth aspect of the present invention, in the steel pipe pile connection structure according to the eighth aspect, the spiral blade 4 is projected from the cylindrical main body 20 of the connection member M.

  A tenth aspect of the present invention is the steel pipe pile connection structure according to the eighth or ninth aspect, wherein the retaining arm 12 of each nut holding portion 9 is the holding wall 11 on the opposite side from the upper end on the near side of the holding wall 11 on one side. The arm main body portion 12a protrudes horizontally toward the opposite portion of the arm main body portion, and the protruding portion 12b protrudes integrally from the inner surface of the tip end portion of the arm main body portion so as to slightly narrow the inlet of the nut holding portion. .

  Claim 11 is the steel pipe pile connection structure according to any one of claims 8 to 10, wherein each holding wall 11 of each nut holding part 9 has a substantially L-shaped vertical wall part 11a in plan view and a vertical wall part 11a. It consists of a nut receiving wall part 11b which protrudes inward from the lower end part of the wall part 11a.

  A twelfth aspect of the present invention is the connecting structure for steel pipe piles according to any of the eighth to eleventh aspects, wherein the back surface portion 14 of the nut holding portion is a pressure contact surface that is pressed by tightening a bolt 13 screwed into the nut 10. Is a plane part.

  Claim 13 is the steel pipe pile connection structure according to any one of claims 8 to 12, wherein the pile main body 1 to be connected to the outer peripheral surface of each of the upper and lower base cylinder portions 21 of the connection member M is an electric resistance steel pipe. In some cases, the groove 15 for receiving the weld bead 22 extending in the longitudinal direction of the steel pipe and projecting toward the inner peripheral surface is provided in the connecting member axial direction.

  According to a fourteenth aspect of the present invention, in the steel pipe pile connection structure according to the thirteenth aspect, the connecting member side bolt insertion hole 8 is provided at a position equidistant from the concave groove portion 15 to the left and right in the connecting member circumferential direction. At the same time, the pile body 1 has seven pile body side bolt insertion holes at the equidistant position n in the circumferential direction of the pile body from the weld bead 22 to the left and right.

  Claim 15 is the steel pipe pile connection structure according to any one of claims 8, 10 to 14, wherein the connection member M is a half of the same shape as a half-divided body obtained by dividing the connection member M into two equal parts. Two split wax models are formed by a wax model forming die, and both half split wax models are joined vertically symmetrically to form a connecting member wax model having the same shape as the connecting member M. It is characterized by being formed by casting using the lost wax method.

  In the connection structure of steel pipe piles according to claims 9 to 14, the connection member M in which the spiral blade 4 protrudes from the cylindrical body 20 includes the cylindrical body 20 in which the spiral blade 4 protrudes. A cylindrical main body wax model with spiral wings having the same shape is molded by a wax model molding die, and two base cylinder wax models having the same shape as the base cylinder portion 21 are molded by a wax model molding die, The model is joined symmetrically to the upper and lower ends of the cylindrical main body wax model with spiral wings to form a connecting member wax model having the same shape as the connecting member M, and cast by the lost wax method using this connecting member wax model. It is formed by doing.

  The connection structure of the steel pipe pile of the invention which concerns on Claim 17 has the same outer diameter as the outer diameter of the pile main body 1, and connects the excavation head 2 to a lower end part in connecting the excavation head 2 to the lower end part of the pile main body 1. A cylindrical connecting member Q is formed by forming a base tube portion 6 in which the outer diameter is smaller than the inner diameter of the pile body 1 and the lower end portion of the pile body 1 is fitted to the upper end portion of the formed cylindrical head body 3. Bolt insertion holes 7 are provided in the lower end of the pile body 1 at regular intervals in the circumferential direction, and the connection end of the pile body 1 is externally fitted to the base tube 6 in the base tube 6 of the connection member Q. A bolt insertion hole 8 is provided at a position that coincides with the pile main body side bolt insertion hole 7 when they are joined, and the inner cylinder surface side of the base cylinder portion 6 is opposed to the base cylinder portion side bolt insertion hole 8 in the axial direction. The nut holding portions 9 for holding the nuts 10 are provided, and each nut holding portion 9 receives the nut 10 inserted from the upper inlet O as the pair. A pair of holding walls 11 and 11 on both sides for receiving the position and restricting the rotation of the nut 10, and a holding wall 11 on one side to prevent the nut 10 from coming out of the inlet O and hold the nut 10 in the opposite position. It is integrally protruded so as to narrow the inlet O, and when inserting the nut, the nut 10 is struck from the inlet to be elastically deformed so as to widen the inlet O, and the insertion is restored after the insertion. It comprises a retaining arm 12 for retaining, and the base tube portion 6 is internally fitted to the lower end portion of the pile body 1 so that the bolt 13 is connected to the base body portion side bolt insertion hole 8 from the pile body side bolt insertion hole 7. The connecting member Q is fixed to the lower end portion of the pile main body 1 by being screwed into the nut 10 held in the nut holding portion 9 by being inserted into the nut holding portion 9.

  An eighteenth aspect is characterized in that, in the steel pipe pile connection structure according to the seventeenth aspect, a spiral blade 4 is projected from the cylindrical head body 3 of the connection member Q.

  Claim 19 is the steel pipe pile connection structure according to claim 17 or 18, wherein the retaining arm 12 of each nut holding part 9 has the holding wall 11 on the opposite side from the upper end on the front side of the holding wall 11 on one side. The arm main body 12a protrudes horizontally toward the opposite portion of the arm main body 12a, and the protrusion 12b integrally protrudes so as to slightly narrow the inlet O of the nut holding portion 9 from the inner surface of the distal end of the arm main body 12a. Features.

  Claim 20 is the steel pipe pile connection structure according to any one of claims 17 to 19, wherein each holding wall 11 of each nut holding part 9 has a substantially L-shaped vertical wall part 11a in plan view and a vertical wall part 11a. It consists of a nut receiving wall part 11b which protrudes inward from the lower end part of the wall part 11a.

  21 is a connecting structure of steel pipe piles according to any one of claims 17 to 20, wherein the nut holding portion 9 is a back surface portion that is a pressure contact surface that is pressed by tightening a bolt 13 screwed into the nut 10. Reference numeral 14 denotes a flat portion.

  Claim 22 is the steel pipe pile connection structure according to any one of claims 17 to 21, wherein the pile body 1 to be connected to the outer peripheral surface of the base tube portion 6 of the connection member Q is an electric resistance steel pipe. A groove 15 for receiving a weld bead 22 extending in the longitudinal direction of the steel pipe and protruding toward the inner peripheral surface is provided in the connecting member axial direction.

  23 is a connecting structure of steel pipe piles according to claim 22, wherein the base cylinder portion side bolt insertion hole 8 is provided at a position equidistant m in the connecting member circumferential direction from the concave groove portion 15 to the left and right thereof. In addition, the pile main body 1 is provided with the pile main body side bolt insertion holes 7 at positions equidistant n in the circumferential direction of the pile main body from the weld bead 22 to the left and right.

  Claim 24 is the steel pipe pile connection structure according to any one of claims 17 and 19 to 23, wherein the connection member Q is a head model mold of the same shape as the cylindrical head body 3. And a base cylinder part wax model having the same shape as the base cylinder part 6 is formed by a wax model molding die, and the base cylinder part wax model is joined to the upper end of the head main body wax model to have the same shape as the connecting member Q. A connecting member wax model is formed, and the connecting member wax model is cast by the lost wax method.

  Claim 25 is the connecting structure of steel pipe piles according to any one of claims 18 to 23, wherein the connecting member Q in which the spiral blade 4 protrudes from the cylindrical head body 3 protrudes from the spiral blade 4. A head body wax model with a spiral wing having the same shape as that of the cylindrical body 3 is molded by a wax model molding die, and a base cylinder wax model having the same shape as the base cylinder portion 6 is molded by a wax model molding die, with a spiral wing. A base cylinder wax model is joined to the upper end of the head body wax model to form a connecting member wax model having the same shape as the connecting member Q, and this connecting member wax model is cast by the lost wax method. It is characterized by that.

  The effect of the invention by the above solution will be described with reference numerals of the embodiments described later. According to the steel pipe pile connection structure of the invention according to claim 1, the upper end of the lower pile body 1 When the lower end portion of the pile body 1 is connected by the connecting member N, the nut 10 is inserted into the upper end side nut holding portion 9 and the lower end side nut holding portion 9 of the connecting member N in advance. The connection work of the main body 1 can be performed efficiently. Thus, in order to insert the nut 10 into each nut holding portion 9, the nut 10 is placed at the inlet O of the upper end side nut holding portion 9 and locked to the protruding portion 12 b of the retaining arm 12. If the nut 10 is tapped with a hammer or the like from the state, the distal end side of the retaining arm 12 with the protruding portion 12b is elastically deformed outward and the inlet O is slightly widened, so the nut 10 is inserted into the nut holding portion 9 as it is. Thus, after the insertion, the retaining arm 12 is restored, and the nut 10 is prevented from coming out, and the nut 10 is held at the opposing position as the connecting member side bolt insertion hole 7. Therefore, the connecting member N that holds the nut 10 in each nut holding portion 9 in this way does not come out of each nut holding portion 9 even if it is turned sideways or repeated upside down. Therefore, the nut 10 can be carried while holding the nut 10 and the pile body 1 can be connected when necessary, so that the work efficiency can be greatly improved. Since the nut holding portion 9 is formed integrally with the connecting member N, it is not necessary to insert the nut holding portion 9 into the nut holding portion 9 like a conventional retaining pin.

  According to the second aspect of the present invention, the retaining arm 12 of each nut holding portion 9 in the connecting member N is horizontally moved from the front upper end portion of the holding wall 11 on one side toward the facing portion of the holding wall 11 on the opposite side. The structure is extremely simple by comprising the arm main body 12a protruding to the right and the protrusion 12b integrally protruding so as to slightly narrow the inlet O of the nut holding portion 9 from the inner surface of the front end of the arm main body 12a. However, the elastic deformation can be accurately performed when the nut 10 is inserted into the nut holding portion 9, and the nut 10 can be inserted and retained effectively.

  According to the invention which concerns on Claim 3, each holding wall 11 of each nut holding part 9 in the connection member N is inward from the vertical wall part 11a of planar view substantially L-shape, and the lower end part of the vertical wall part 11a. By adopting a configuration including the protruding nut receiving wall portion 11b, the nut 10 can be reliably held while the structure is extremely simple.

  According to the fourth aspect of the present invention, in the connecting member N, the back surface portion 14 of the nut holding portion 9 that serves as a pressure contact surface that is pressed by tightening the bolt 13 screwed to the nut 10 is a flat surface portion. The end face of 10 is in full contact with the back surface portion 14 of the nut holding portion 9 so that the nut 10 can be securely and firmly fastened to the back surface portion 14.

  According to the invention which concerns on Claim 5, when the pile main body 1 to connect to the outer peripheral surface of the connection member N is an ERW steel pipe, in order to receive the weld bead 22 which extends in a steel pipe longitudinal direction and protrudes to an inner peripheral surface side Since the concave groove portion 15 is provided in the connecting member axial direction, the connecting end portion of the pile body 1 is connected as it is without cutting the weld bead 22 protruding toward the inner peripheral surface side of the pile body 1. The end of the member N can be fitted, so that no extra work is required and work efficiency is improved.

  According to the invention of claim 6, the connecting member side bolt insertion hole 8 is provided at a position equidistant m in the connecting member circumferential direction from the concave groove portion 15 to the left and right thereof, and the pile body 1 has the weld bead 22. Since the pile main body side bolt insertion hole 7 is provided at the position of the equidistant n in the circumferential direction of the pile main body from the left to the right, the weld bead 22 of the pile main body 1 is recessed with the connecting member N. The pile body side bolt insertion hole 7 and the connection member side bolt insertion hole 8 can be matched by fitting the connection end of the pile body 1 to the end of the connection member N so as to be received by the groove 15. The connection work efficiency is further improved.

  According to the seventh aspect of the present invention, the connecting member N is formed by molding two halved wax models Wn having the same shape as the halves obtained by dividing the connecting member N into two halves from the wax model forming die. Formed by joining the halved wax models Wn and Wn symmetrically to form a connecting member wax model WN having the same shape as the connecting member N, and casting the lost wax method using this connecting member wax model WN. In this case, the connecting member N can be manufactured in a short period of time and the manufacturing cost can be significantly reduced as compared with the case where the entire connecting member N is cast at the same time. That is, in the above-described conventional connecting member, the inlet of the upper end side nut holding portion and the inlet of the lower end side nut holding portion are formed in the same upward direction, so that the wax model mold (wax molding die) is the connecting member. Although it is necessary to form a wax model having the same shape as the whole, when the connecting member N is cast by the lost wax method, the connecting member N has a vertically symmetrical shape and is half of the connecting member N. Since it is only necessary to form a wax model forming mold for forming a half-shaped wax model Wn having the same shape as a certain half-divided body, the manufacturing cost can be greatly reduced.

  According to the connection structure of the steel pipe pile of the invention which concerns on Claim 8, in connecting the lower end part of the upper pile main body 1 to the upper end part of the lower pile main body 1, it has the same outer diameter as the outer diameter of the pile main body 1 The upper and lower base cylinder parts 21 which the outer diameter is smaller than the inner diameter of the pile main body 1, and the lower end part of the upper pile main body 1 and the upper end part of the lower pile main body 1 are fitted to the upper and lower ends of the cylindrical main body 20, respectively. , 21 is formed, and the upper end of the lower pile body 1 and the lower end of the upper pile body 1 are provided with bolt insertion holes 7 at regular intervals in the circumferential direction. Each of the upper and lower base tube portions 21 of M is provided with a bolt insertion hole 8 at a position that matches the pile body side bolt insertion hole when the connecting end portion of the pile body 1 is externally fitted to the base tube portion 21. The nut 10 is held on the inner peripheral surface side of the tube portion 21 at a position facing each base tube portion side bolt insertion hole 8 in the axial direction. Since the nut holding portion 9 is provided, the nut 10 is inserted into the nut holding portions 9 of the upper and lower base tube portions 21 of the connecting member M prior to the connecting operation, thereby connecting the pile body 1. Can be performed efficiently. Thus, in order to insert the nut 10 into each nut holding portion 9, the nut 10 is placed at the inlet O of the upper end side nut holding portion 9 and locked to the protruding portion 12 b of the retaining arm 12. If the nut 10 is tapped with a hammer or the like from the state, the distal end side of the retaining arm 12 with the protruding portion 12b is elastically deformed outward and the inlet O is slightly widened, so the nut 10 is inserted into the nut holding portion 9 as it is. Thus, after the insertion, the retaining arm 12 is elastically returned to the original position to prevent the nut 10 from being pulled out, and the nut 10 is held at the opposing position as the connecting member side bolt insertion hole 7. . Therefore, the connecting member M that holds the nut 10 in each nut holding portion 9 in this way does not come out of each nut holding portion 9 even if it is turned sideways or repeated upside down. It can be carried while holding the nut 10 in the nut holding portion 9, and the connecting operation of the pile body 1 can be performed when necessary, so that the work efficiency is greatly improved. Since the nut holding part 9 is formed integrally with the connecting member M, it is not necessary to insert the nut holding part 9 into the nut holding part like a conventional retaining pin.

  According to the invention which concerns on Claim 9, in manufacture of the steel pipe pile K which has the spiral wing | blade 4 in an intermediate part, by using the connection member M which protruded the spiral wing | blade 4 in the cylindrical main body 20, it is a pile driving site. Since the pile body 1 and the connecting member M are separated and stacked separately on the truck bed when transporting to the site, the loading efficiency is improved and the transportation cost is greatly reduced. It becomes possible.

  According to the tenth aspect of the present invention, the retaining arm 12 of each nut holding portion 9 in the connecting member M is moved horizontally from the upper end on the near side of the holding wall 11 on one side toward the facing portion of the holding wall 11 on the opposite side. Although the structure is extremely simple, the structure includes an arm main body portion 12a that protrudes inward and a projection portion 12b that protrudes integrally so as to slightly narrow the inlet of the nut holding portion from the inner side surface of the tip end portion of the arm main body portion. Further, the elastic deformation can be accurately performed when the nut 10 is inserted into the nut holding portion 9, and the nut 10 can be effectively inserted and retained.

  According to the invention which concerns on Claim 11, each holding wall 11 of each nut holding part 9 in the connection member M is made inward from the vertical wall part 11a of planar view substantially L shape, and the lower end part of the vertical wall part 11a. By adopting a configuration including the protruding nut receiving wall portion 11b, the nut 10 can be reliably held while the structure is very simple.

  According to the twelfth aspect of the present invention, in the connecting member N, the back surface portion 14 of the nut holding portion 9 which is a pressure contact surface pressed by tightening the bolt 13 screwed to the nut 10 is a flat portion. The end face of 10 is in full contact with the back surface portion 14 of the nut holding portion 9, so that the nut 10 can be securely and firmly fastened to the back surface portion 14.

  According to the invention which concerns on Claim 13, when the pile main body 1 connected to the outer peripheral surface of the upper and lower each base cylinder part 21 of the connection member M is an electric-resistance-welded steel pipe, it extends to a steel pipe longitudinal direction, and is on the inner peripheral surface side. Since the recessed groove 15 for receiving the protruding weld bead 22 is provided in the connecting member axial direction, the pile main body 1 is left as it is without cutting the weld bead 22 protruding toward the inner peripheral surface of the pile main body 1. Thus, the end of the connecting member M can be fitted to the connecting end of the connecting member M, so that no extra work is required and work efficiency is improved.

  According to the invention of claim 14, the connecting member side bolt insertion hole 8 is provided at a position equidistant m in the connecting member circumferential direction from the concave groove portion 15 to the left and right of the concave groove portion 15. When connecting the pile main body 1 in which the pile main body side bolt insertion holes are provided at positions equidistant n in the circumferential direction of the pile main body to the left and right from the base point 22, the weld bead 22 of the pile main body 1 is connected to the connecting member N. By fitting the end of the connecting member M to the connecting end of the pile body 1 so as to be received by the concave groove 15, the pile body side bolt insertion hole 7 and the connecting member side bolt insertion hole 8 can be matched. Therefore, the connection work efficiency is further improved.

  According to the fifteenth aspect of the present invention, the connecting member M is formed by molding two halved wax models having the same shape as the halves obtained by bisecting the connecting member M into the upper and lower parts by the wax model forming die. When the halved wax model is joined symmetrically in the vertical direction to form a connecting member wax model having the same shape as the connecting member M, and the connecting member wax model is cast by the lost wax method, Compared to the case where the entire member M is cast at the same time, the connecting member M can be manufactured in a short period of time, and the manufacturing cost can be significantly reduced. That is, in the conventional connecting member described above, the inlet of the upper end side nut holding part and the inlet of the lower end side nut holding part are formed in the same upward direction. Therefore, the wax model forming die forms the whole connecting member. However, when this connecting member M is cast by the lost wax method, the connecting member M has a vertically symmetric shape, and a half-shaped wax model having the same shape as the half of the connecting member M is formed. Therefore, the manufacturing cost can be greatly reduced.

  According to the sixteenth aspect of the present invention, the connecting member M with the spiral blade 4 in which the spiral blade 4 projects from the cylindrical body 20 has the same shape as that of the cylindrical body 20 with the spiral blade 4 projecting. A cylindrical main body wax model is molded by a wax model molding die, and two base cylinder wax models having the same shape as the base cylinder portion 21 are molded by a wax model molding die, and both base cylinder wax models are formed by the cylinder with the spiral blades. When forming a connecting member wax model having the same shape as the connecting member M by joining the upper and lower ends of the main body wax model symmetrically in the vertical direction, and casting by the lost wax method using this connecting member wax model Can manufacture the connecting member M in a short period of time and can significantly reduce the manufacturing cost.

  According to the connection structure of the invention according to claim 17, when connecting the excavation head 2 to the lower end portion of the pile main body 1, the excavation head 2 is formed at the lower end portion having the same outer diameter as the outer diameter of the pile main body 1. A cylindrical connecting member Q is formed on the upper end portion of the cylindrical head body 3 by forming a base tube portion 6 whose outer diameter is smaller than the inner diameter of the pile body 1 and into which the lower end portion of the pile body 1 is externally fitted. Bolt insertion holes 7 are provided in the lower end portion of the pile body 1 at regular intervals in the circumferential direction, and the connection end portion of the pile body 1 is externally fitted to the base tube portion 6 of the connection member Q. In addition, a bolt insertion hole 8 is provided at a position that matches the pile main body side bolt insertion hole 7, and the inner peripheral surface side of the base cylinder portion 6 is opposed to the base cylinder portion side bolt insertion hole 8 in the axial direction. Since the nut holding portion 9 for holding the nut 10 is provided, the nuts of the upper and lower base tube portions 21 of the connecting member Q are prior to the connecting operation. By previously inserting a respective nut 10 advance to the holding portion 9 can be efficiently performed the connecting operation of the pile body 1. Thus, in order to insert the nut 10 into each nut holding portion 9, the nut 10 is placed at the inlet O of the upper end side nut holding portion 9 and locked to the protruding portion 12 b of the retaining arm 12. If the nut 10 is tapped with a hammer or the like from the state, the distal end side of the retaining arm 12 with the protruding portion 12b is elastically deformed outward and the inlet O is slightly widened, so the nut 10 is inserted into the nut holding portion 9 as it is. Thus, after the insertion, the retaining arm 12 is elastically returned to the original position to prevent the nut 10 from being pulled out, and the nut 10 is held at the opposing position as the connecting member side bolt insertion hole 7. . Therefore, the connecting member Q that holds the nut 10 in each nut holding portion 9 in this way does not come out of each nut holding portion 9 even if it is turned sideways or repeated upside down. It can be carried while holding the nut 10 in the nut holding portion 9, and the connecting operation of the pile body 1 can be performed when necessary, so that the work efficiency is greatly improved. Since the nut holding portion 9 is formed integrally with the connecting member Q, it is not necessary to insert the nut holding portion 9 into the nut holding portion like a conventional retaining pin.

  According to the invention of claim 18, since the spiral blade 4 projects from the cylindrical head body 3 of the connecting member Q, the excavation head 2 with the spiral blade 4 can be easily and easily attached to the lower end of the pile body 1. Can be attached.

  According to the nineteenth aspect of the present invention, the retaining arm 12 of each nut holding portion 9 in the connecting member Q is moved horizontally from the front upper end portion of the holding wall 11 on one side toward the facing portion of the holding wall 11 on the opposite side. The structure is extremely simple by including the arm main body portion 12a protruding inward and the protruding portion 12b integrally protruding so as to slightly narrow the inlet O of the nut holding portion 9 from the inner surface of the tip end portion of the arm main body portion 12a. However, the elastic deformation can be accurately performed when the nut 10 is inserted into the nut holding portion 9, and the nut 10 can be inserted and retained effectively.

  According to the invention which concerns on Claim 20, each holding wall 11 of each nut holding part 9 in the connection member Q is inward from the vertical wall part 11a of planar view substantially L-shape, and the lower end part of the vertical wall part 11a. Since it consists of the nut receiving wall part 11b which protrudes, the nut 10 can be reliably hold | maintained, although a structure is very simple.

  According to the twenty-first aspect of the present invention, in the connecting member Q, the back surface portion 14 of the nut holding portion 9 that serves as a pressure contact surface that is pressed by tightening the bolt 13 that is screwed onto the nut 10 is a flat portion. The end face of 10 is in full contact with the back surface portion 14 of the nut holding portion 9, so that the nut 10 can be securely and firmly fastened to the back surface portion 14.

  According to the invention which concerns on Claim 22, when the pile main body 1 connected to the outer peripheral surface of the base cylinder part 6 of the connection member Q is an ERW steel pipe, it extends in the steel pipe longitudinal direction and protrudes to the inner peripheral surface side. Since the concave groove 15 for receiving the weld bead 22 is provided in the connecting member axial direction, the pile main body 1 can be left as it is without cutting the weld bead 22 protruding toward the inner peripheral surface of the pile main body 1. Thus, the end of the connecting member Q can be fitted to the end of the connecting member Q, so that no extra work is required and the work efficiency is improved.

  According to the invention of claim 23, the base cylinder portion side bolt insertion hole 8 is provided at a position equidistant m in the circumferential direction of the connecting member from the concave groove portion 15 to the left and right thereof, and the pile main body 1 is welded. Since the pile body side bolt insertion hole 7 is provided at a position equidistant n in the circumferential direction of the pile body from the bead 22 to the left and right, when connecting the excavation head 2 to the lower end of the pile body 1, the pile By fitting the connecting end portion of the pile body 1 to the base tube portion 21 so that the weld bead 22 of the body 1 is received by the recessed groove portion 15 of the base tube portion 21, the pile body side bolt insertion hole 7 and the base tube portion side Since the bolt insertion hole 8 can be matched, the connection work efficiency is further improved.

  According to the twenty-fourth aspect of the present invention, the connecting member Q is formed by molding a head main body wax model having the same shape as the cylindrical head main body 3 by the wax model forming die and having the same shape as the base cylinder portion 6. The model is molded by a wax model molding die, and a base tube wax model is joined to the upper end of the head body wax model to form a connecting member wax model having the same shape as the connecting member Q. When formed by casting by the wax method, the connecting member Q having a precise structure can be easily manufactured.

  According to the invention of claim 25, the connecting member Q having the spiral blade 4 on the cylindrical head body 3 is connected to the head body row model with the spiral blade having the same shape as the cylindrical body 3 projecting the spiral blade 4. Molded with a model mold and molded with a wax model mold of a base cylinder part wax model having the same shape as the base tube part 6, and joined and connected to the upper end of the head body wax model with a spiral wing. When the connecting member wax model having the same shape as the member Q is formed and cast by the lost wax method using the connecting member wax model, the connecting member Q having the spiral blade 4 can be easily manufactured. It is.

It is a perspective view which shows embodiment of the connection member of the steel pipe pile which concerns on this invention. (a) is a plan view of the connecting member, (b) is a front view, and (c) is a sectional view taken along line DD of (a). 2A is a sectional view taken along line AA in FIG. 2B, FIG. 2B is a sectional view taken along line BB in FIG. 2A, and FIG. 2C is a sectional view taken along line CC in FIG. It is line sectional drawing. (a) is a plan view of a half-split wax model formed in the same shape as a half-split divided into two halves of the connecting member, (b) is a front view, and (c) is a EE line of (a). It is sectional drawing. (a-1) is a front view showing the state before joining the two halved wax models shown in FIG. 4, (a-2) is a longitudinal sectional view of the same state, and (b-1) is two The front view of the state which joined the halved wax model integrally, (b-2) is the longitudinal cross-sectional view of the state. The state which has inserted the nut from the inlet of the upper part in the nut holding part of a connection member is shown, (a) is a top view which expands and shows a part of connection member, (b) is F of (a). FIG. FIG. 2 shows a state in which a nut is inserted into a nut holding portion, (a) is an enlarged plan view showing a part of a connecting member, and (b) is a front view. It is a front view of the state which is going to connect the lower end part of an upper pile main body to the upper end part of a lower pile main body. It is a front view of the state which connected both pile main bodies. (a) is a plan view showing a state in which the bolt is about to be screwed into the nut in the holding portion from the bolt body side bolt insertion hole through the connecting member side bolt insertion hole, and (b) is a plan view of the bolt being screwed in. It is. (a) is a perspective view which shows the pile main body which consists of an ERW steel pipe, (b) is sectional drawing of the state in which the weld bead of the pile main body plunged into the groove part for welding bead reception of a connection member. It is a perspective view showing an embodiment of a multi-blade type steel pipe pile. (a) And (b) is a perspective view which shows the connection member used for manufacture of a multiblade-type steel pipe pile. It is explanatory sectional drawing which shows the assembly | attachment method in the case of manufacturing a multiblade-type steel pipe pile.

  A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cylindrical connecting member N for connecting a steel pipe pile K as shown in FIGS. In connecting the lower end portion of the upper pile body 1 to the upper end portion of the pile body 1, the lower half portion is fitted into the upper end portion of the lower pile body 1 and the upper half portion is the lower end portion of the upper pile body 1. Are adapted to be fitted inside. Each steel pipe pile K is provided with bolt insertion holes 7 (see FIG. 8) at the upper end and lower end of the pile body 1 at regular intervals in the circumferential direction.

  The connecting member N is formed in a cylindrical shape having an outer diameter slightly smaller than the inner diameter of the pile body 1 of the steel pipe pile K to be connected, and is made of a casting as described later. On the upper end side and the lower end side of the connecting member N, bolt insertion holes 8 are provided at positions that match the pile body side bolt insertion holes 7 when the connecting member N is internally fitted to the connection end of the pile body 1. As shown in FIGS. 1 to 3, 6, and 7, the connecting member side bolt insertion holes 8 are arranged in the axial direction on the inner peripheral surface side of the connecting member N. A nut holding portion 9 is provided to hold the nut 10 at an opposing position, and each nut holding portion 9 on the upper end side receives the nut 10 inserted from the upper inlet O at the opposite position and rotates the nut 10. In order to prevent the nut 10 from coming out of the pair of holding walls 11 and 11 and the inlet O to be restricted and to hold the nut 10 in the opposite position, the inlet O is slightly narrowed to the holding wall 11 on one side. When projecting the nut, It is composed of a retaining arm 12 that elastically deforms so as to widen the inlet O by hitting the nut 10 with a hammer or the like from the inlet O, and allows the insertion to be restored after insertion to prevent the nut 10 from coming off. Each nut holding part 9 on the lower end side is formed vertically symmetrically with each nut holding part 9 on the upper end side.

  Then, as shown in FIG. 8, the lower half of the connecting member N is fitted into the upper end of the lower pile body 1, and the bolt 13 is inserted from the pile body side bolt insertion hole 7 into the connection member side bolt insertion hole 8. Then, the connecting member N is fixed to the upper end portion of the lower pile body 1 by screwing into the nut 10 held in the nut holding portion 9, and the upper half portion of the connecting member N is fixed to the upper pile body. 1 is internally fitted to the lower end of 1, the bolt 13 is inserted from the pile body side bolt insertion hole 7 to the connecting member side bolt insertion hole 8, and is screwed into the nut 10 held by the nut holding portion 9. The connecting member N is fixed to the lower end portion of the upper pile main body 1, and the two pile main bodies 1 and 1 are integrally connected.

  As can be seen from FIGS. 6 and 7, the retaining arm 12 of each nut holding portion 9 is an arm that protrudes horizontally from the upper end on the near side of the holding wall 11 on one side toward the opposite portion of the holding wall 11 on the opposite side. It is formed by a main body portion 12a and a projection portion 12b that protrudes integrally from the inner side surface of the distal end portion of the arm main body portion 12a so as to slightly narrow the inlet of the nut holding portion 9. Moreover, each holding wall 11 of each nut holding part 9 protrudes inwardly from the vertical wall part 11a of planar view substantially L-shape, and the lower end part of this vertical wall part 11a so that FIG.6 and FIG.7 may show. It is formed by the nut receiving wall part 11b. As shown in FIG. 6B, the nut receiving wall portion 11b has an upper surface formed on an inclined surface having an inclination angle θ of about 30 ° with respect to a horizontal plane. The inclination angle θ of this inclined surface is 30 °. When the hexagon nut 10 is accommodated and held in the nut holding portion 9 as shown in the drawing, the left and right end surfaces of the nut 10 are positioned in parallel with the left and right vertical wall portions 11a and 11a. In this state, the lower end surface side is an angle at which the entire nut 10 can be held in a stable state by being perfectly engaged with the inclined surfaces of the left and right nut receiving wall portions 11b, 11b.

  Further, as can be seen from FIGS. 6 (a) and 7 (a), the back surface portion 14 of the nut holding portion 9 serving as a pressure contact surface by the tightening of the bolt 13 screwed to the nut 10 is: Although the outer peripheral surface portion of the connecting member N is formed in a circular arc shape, the end surface of the nut 10 is entirely connected to the back surface portion 14 of the nut holding portion 9 since it is formed in a flat shape and becomes a flat surface portion. As a result, the nut 10 can be securely and firmly fastened to the back surface portion 14.

  Moreover, as shown in FIG.2 and FIG.3, when the pile main body 1 of the steel pipe pile K is an ERW steel pipe, as shown in FIG. A concave groove 15 for receiving a weld bead 22 protruding toward the inner peripheral surface of the pile body 1 is provided in the connecting member axial direction. That is, as shown in FIG. 11 (a), in an ERW steel pipe formed by joining the longitudinal seam portions of the steel pipe by, for example, high frequency induction welding, the weld bead 22 protrudes on the inner peripheral side of the welded portion. (The weld bead protruding to the outer peripheral side of the welded joint is mechanically cut in parallel with the welding operation), so that the connecting member is directly connected to the pile body 1 of the steel pipe pile K made of such an electric resistance steel pipe. Even if it is going to fit N, since the weld bead 22 which protrudes to the inner peripheral side of a steel pipe hits and it cannot fit, the concave groove part 15 which receives this weld bead 22 is one or the circumferential direction on the outer peripheral surface of the connection member N A plurality of (four in this embodiment) are provided at necessary intervals. The weld bead 22 protruding to the inner peripheral side of the electric resistance welded pipe may be cut off, but the cutting work takes time, so in most cases it remains protruding.

  As shown in FIG. 3 and FIG. 11 (b), the connecting member N is positioned equidistantly m in the connecting member circumferential direction from the left and right of the groove 15 provided on the outer peripheral surface of the connecting member N. The connection member side bolt insertion holes 8 are provided, and the connection member side bolt insertion holes 8 are provided at a constant interval (m × 2) in the circumferential direction of the connection member N as shown in FIG. . In addition, as shown in FIG. 11 (b), the pile main body side bolt insertion hole 7 is located at the position of the equidistant n in the circumferential direction of the pile main body on the left and right sides of the weld bead 22 as shown in FIG. This pile body side bolt insertion hole 7 is also provided at a constant interval (n × 2) in the circumferential direction of the pile body 1 as shown in FIG. The bolt insertion hole 7 of the pile body 1 and the bolt insertion hole 8 of the connecting member N are in a relationship that matches each other when the connecting member N is fitted inside the connecting end of the pile body 1. In FIG. 11 (b), the distance in the circumferential direction between the recessed groove portion 15 provided in the connecting member N and the connecting member side bolt insertion hole 8 adjacent to the right and left of the recessed groove portion 15 is m, Although the circumferential distance between a certain weld bead 22 and the pile main body side bolt insertion hole 7 adjacent to the left and right of the weld bead 22 is n, it is illustrated in a position radially away from the connecting member N and the pile main body 1. The distance m is actually the circumferential center distance between the concave groove 15 in the connecting member N and the connecting member side bolt insertion hole 8, and the distance n is the pile body. 1 is a circumferential center distance between the weld bead 22 and the pile main body side bolt insertion hole 7.

  As described above, the connecting member N is provided with the connecting member-side bolt insertion holes 8 at positions equidistant m in the connecting member circumferential direction from the concave groove portion 15 to the left and right of the connecting member N, and the pile body 1 has a weld bead. Since the pile body side bolt insertion hole 7 is provided at the position of the equidistant n in the circumferential direction of the pile body from the left and right of the base point 22, when connecting the pile body 1, the weld bead 22 of the pile body 1 is connected to the connection member N. By fitting the connecting end portion of the pile body 1 to the end portion of the connecting member N so as to be received by the recessed groove portion 15, the pile body side bolt insertion hole 7 and the connecting member side bolt insertion hole 8 can be matched. Thus, the connecting operation can be performed more efficiently.

  Further, as shown in FIGS. 2 and 3, the upper and lower end portions of the connecting member N are chamfered at their outer peripheral edge portions to form a chamfered portion 16. Thus, by chamfering the outer peripheral edge of the upper and lower ends of the connecting member N, the fitting operation to the upper and lower ends of the pile body 1 can be performed quickly and easily.

  As shown in FIGS. 4 and 5, the connecting member N described above is formed by molding two halved wax models Wn having the same shape as a halved body obtained by dividing the connecting member N into two halves from a wax model forming die. Then, both halved wax models Wn, Wn are joined symmetrically in the vertical direction to form a connecting member wax model WN having the same shape as the connecting member N, and the connecting member wax model WN is cast by the lost wax method. It is formed by. FIG. 4 (a) is a plan view of a half-row model Wn formed by a wax model mold (wax mold) (not shown) in the same shape as a half that is obtained by dividing the connecting member N into two equal parts. (B) is the front view, (c) is the EE sectional view taken on the line (a). The halved wax model Wn shown here has the same structure as the halved body obtained by dividing the connecting member N described above with reference to FIGS. 2, 3, 6 and 7 into two equal parts. The constituent elements are the same as those of the connecting member N, and are given the same reference numerals.

  In casting of the connecting member N by the lost wax method, as shown in FIGS. 4A to 4C, the connecting member N is divided into two halves by a wax model mold (wax molding die). Two halved wax models Wn of the same shape as the body are formed, and the two halved wax models Wn and Wn are vertically symmetrical as shown in FIGS. 5 (a-1) and (a-2). The overlapping end portions are melt-bonded by heating to form a connecting member wax model WN having the same shape as the connecting member N as shown in FIGS. 3 (b-1) and (b-2). Then, a mold forming agent (not shown) such as ceramic slurry is attached to the surface of the connecting member wax model WN, and this mold forming agent is solidified to form a mold (not shown), and then the connecting member wax model WN. Is heated and melted to remove the wax model WN from the mold, and the connecting member N is cast by this mold. Cast iron, cast steel, stainless steel, and alloy steel can be used as the casting material used for casting the connecting member N.

  According to the connecting member N formed by casting by the lost wax method as described above, the connecting member N can be manufactured in a short time and the manufacturing cost is remarkably reduced as compared with the case where the entire connecting member N is cast at the same time. Can be cheap. That is, in general, the lost wax casting method is to precisely create a model of the same shape as the target object with wax (wax), harden the periphery with a mold forming agent (ceramic shell, etc.) made of a refractory, and then heat to form a wax model. This is a method in which molten metal is poured into the space after disappearance (lost) and cooled to cast a casting of the desired shape. This casting method is short-term even for hard, uncuttable metals or complex shapes that require core fabrication. It has a feature that the shape can be easily reproduced. In the conventional connecting member, the inlet of the upper end side nut holding part and the inlet of the lower end side nut holding part are formed in the same upward direction, so that the wax model mold (wax forming mold) is the entire connecting member. However, when the connecting member N is cast by the lost wax method, the connecting member N has a vertically symmetric shape and is half of the connecting member N. Since it is only necessary to form a wax model forming mold for forming the half wax model Wn having the same shape as the half, the manufacturing cost can be greatly reduced.

  Using the connecting member N configured as described above, the lower end portion of the pile body 1 of the upper steel pipe pile K is connected to the upper end portion of the pile body 1 of the lower steel pipe pile K as shown in FIGS. To do so, first, the nut 10 is inserted into the nut holding portion 9 provided on the upper end side and the lower end side on the inner peripheral surface side of the connecting member N. The nut 10 is inserted into the nut holding portion 9 by placing the nut 10 at the inlet O of the upper end side nut holding portion 9 as shown by phantom lines in FIGS. 6 (a) and 6 (b). When the nut 10 is lightly tapped with a hammer or the like from this state, the distal end side of the retaining arm 12 with the protrusion 12b is elastically deformed outward, and the inlet O Since the nut 10 is slightly expanded, the nut 10 is inserted into the nut holding portion 9 to be in the state shown in the phantom line in FIG. 6 (b) and the solid line in FIG. 7 (b). As shown in FIGS. 6 (a) and 7 (a), the side returns to the original position and is prevented from being detached by the retaining arm 12. When the insertion of the nut 10 into the upper end side nut holding portion 9 is finished in this way, the connecting member N is repeatedly turned upside down with respect to the nut holding portion 9 originally on the lower end side. In the same manner as above, the nut 10 is inserted, and the retaining arm 12 prevents the retaining.

  Then, after fitting the lower half of the connecting member N into the upper end of the pile main body 1 of the lower steel pipe pile K, the bolt 13 is inserted into the pile main body side bolt as shown in FIG. 10 is inserted into the connecting member side bolt insertion hole 8 from the hole 7 and the tip end portion of the bolt 13 is screwed into the nut 10 held in each nut holding portion 9 to be tightened. As shown in FIG. 8, the connecting member N is crimped to the upper end of the pile body 1, and the lower half of the connecting member N is attached and fixed to the upper end of the pile body 1 of the lower steel pipe pile K as shown in FIG. .

  Thus, after fixing the lower half part of the connection member N to the upper end part of the pile main body 1 of the lower steel pipe pile K, as shown in FIG. 8, the connection member N which protrudes from the upper end of the pile main body 1 of the lower steel pipe pile K is shown. The lower end portion of the pile body 1 of the upper steel pipe pile K is externally fitted to the upper half portion of the upper steel pipe pile, and the bolt is inserted into the connecting member side bolt insertion hole 8 from the bolt insertion hole 7 at the lower end portion of the pile body 1 of the upper steel pipe pile K. 13, the lower end portion of the pile body 1 of the upper steel pipe pile K is connected to the upper half of the connecting member N by screwing and tightening the tip portion of the nut portion 10 in the nut holding portion 9. As a result, the ends of the pile main body 1 of the upper steel pipe pile K and the pile main body 1 of the lower steel pipe pile K can be integrally connected via the connecting member N. FIG. 9 shows the appearance of this connection structure.

  When connecting the lower end part of the pile body 1 of the upper steel pipe pile K to the upper end part of the pile body 1 of the lower steel pipe pile K as described above by the connecting member N, preferably in a factory or the like prior to the connection work. By previously inserting the nut 10 into the upper end side nut holding part 9 and the lower end part side nut holding part 9 of the connecting member N, the connection work of the pile main body 1 can be performed efficiently. Thus, when the nut 10 is inserted into each nut holding portion 9, the nut 10 is placed at the inlet O of the upper end side nut holding portion 9 and is locked to the protruding portion 12 b of the retaining arm 12. If the nut 10 is tapped with a hammer or the like from the state, the distal end side of the retaining arm 12 with the protruding portion 12b is elastically deformed outward and the inlet O is slightly widened, so the nut 10 is inserted into the nut holding portion 9 as it is. Thus, after the insertion, the retaining arm 12 is elastically returned to the original position to prevent the nut 10 from being pulled out, and the nut 10 is held at the opposing position as the connecting member side bolt insertion hole 7. . Therefore, the connecting member N that holds the nut 10 in each nut holding portion 9 in this way does not come out of each nut holding portion 9 even if it is turned sideways or repeated upside down. It can be carried while holding the nut 10 in the nut holding part 9, and the connecting operation of the pile body 1 can be performed when necessary, so that the work efficiency at the site can be greatly improved.

  In the embodiment described above, the retaining arm 12 of each nut holding portion 9 is provided with an arm main body portion 12a that protrudes horizontally from the front upper end portion of the holding wall 11 on one side toward the opposing portion of the holding wall 11 on the opposite side. The nut holding portion has a structure that is extremely simple by having a configuration including a protruding portion 12b that integrally protrudes so as to slightly narrow the inlet O of the nut holding portion 9 from the inner side surface of the distal end portion of the arm main body portion 12a. When the nut 10 is inserted into the nut 9, the elastic deformation can be performed accurately, and the nut 10 can be inserted and retained effectively.

  Further, in the embodiment, each holding wall 11 of each nut holding portion 9 includes a substantially L-shaped vertical wall portion 11a in plan view and a nut receiving wall portion 11b protruding inward from the lower end portion of the vertical wall portion 11a. Therefore, the nut 10 can be reliably held while the structure is extremely simple.

  In the embodiment, since the back surface portion 14 of the nut holding portion 9 which is a pressure contact surface that is pressed by tightening the bolt 13 screwed into the nut 10 is a flat portion, the end surface of the nut 10 is entirely the nut holding portion. 9, the nut 10 can be stably and firmly fastened to the back surface portion 14.

  The above is an explanation of the connection structure of steel pipe piles K applied to pile driving work in which piles of a predetermined length are successively added until the pile tip reaches the support layer. Next, a steel pipe pile is manufactured. In the description, an embodiment of a connection structure in which a steel pipe pile K is manufactured by dividing a pile body of one steel pipe pile into a plurality of pieces and connecting the divided bodies to each other will be described.

  12 shows a multi-blade type steel pipe pile K in which the excavation head 2 with the spiral blade 4 is provided at the lower end portion of the pile body 1 and the spiral blade 4 is provided at the intermediate required portion of the pile body 1. ) Shows a connecting member M for connecting the pile main bodies 1 and 1, (b) shows a connecting member Q for connecting the excavation head 2 with the spiral blade 4 to the lower end of the pile main body 1, and FIG. The method of assembling the type steel pipe pile K will be shown.

  As shown in FIG. 13A and FIG. 14, the connecting member M has an outer diameter that is larger than the inner diameter of the pile body 1 at the upper and lower ends of the cylindrical body 20 having the same outer diameter as the pile body 1. The upper and lower base cylinders 21 and 21 are formed by the lower end of the lower pile body 1 and the upper end of the lower pile body 1 being respectively fitted outside. Bolt insertion holes 7 are provided in the lower end portion of the pile body 1 at regular intervals in the circumferential direction, and the connecting end portion of the pile body 1 is externally fitted to the base tube portion 21 in the upper and lower base tube portions 21 of the connecting member M. A bolt insertion hole 8 is provided at a position coinciding with the pile main body side bolt insertion hole 7 when combined, and the inner peripheral surface side of each base cylinder part 21 is opposed to each base cylinder part side bolt insertion hole 8 in the axial direction. Nut holding portions 9 for holding the nuts 10 at opposite positions are provided, and each nut holding portion 9 on the upper end side is inserted from the upper inlet O. In order to prevent the nut 10 from coming out of the inlet O and to hold the nut 10 in the facing position, while holding the nut 10 in the facing position and restricting the rotation of the nut 10 on both sides. The inlet wall O is integrally protruded to the holding wall 11 on one side, and when inserting the nut, the insertion is performed by elastically deforming to widen the inlet port O by striking the nut 10 from the inlet port O. Is constituted by a retaining arm 12 for restoring and retaining the nut 10, and each nut holding portion 9 on the lower end side is formed symmetrically with each nut holding portion 9 on the upper end side. Although the spiral blade 4 protrudes from the cylindrical body 20 of the connecting member M, the spiral blade 4 may not protrude from the cylindrical body 20 in some cases.

  The nut holding part 9 provided on the inner peripheral surface side of the upper and lower base tube parts 21 of the connecting member M has the same configuration as the nut holding part 9 in the connecting member N described with reference to FIGS. Moreover, in the outer peripheral surface of each upper and lower base cylinder part 21, when the pile main body 1 is an ERW steel pipe, it is for receiving the weld bead 22 (refer FIG. 11) extended in a steel pipe longitudinal direction and projecting to an inner peripheral surface side. The concave groove portion 15 is provided in the connecting member axial direction.

  Further, the connecting member M has the same shape as a half-divided body obtained by dividing the connecting member M into upper and lower parts when the spiral blade 4 is not provided on the cylindrical main body 20, although the description thereof is omitted. Two halved wax models are molded by a wax model mold, and both halved wax models are joined symmetrically in the vertical direction to form a connecting member wax model having the same shape as the connecting member M. It is formed by casting with a lost wax method using a model. A specific manufacturing method is the same as the casting method of the connecting member N described with reference to FIGS. Further, when the spiral blade 4 protrudes from the cylindrical main body 20, the connecting member M is a cylindrical main body wax model with a spiral blade having the same shape as the cylindrical main body 20 protruding from the spiral blade 4. Molded with a wax model mold, and molded with a wax model mold two base cylinder wax models having the same shape as the base cylinder part 21, and both base tube part wax models of the cylindrical main body wax model with spiral wings. A connecting member wax model having the same shape as the connecting member M is formed by joining the upper and lower ends symmetrically, and the connecting member wax model is cast by the lost wax method using the connecting member wax model.

  Moreover, the connection member Q which connects the excavation head 2 with the spiral blade 4 to the lower end part of the pile main body 1 has the same outer diameter as the outer diameter of the pile main body 1, as shown in FIG. 13 (b) and FIG. At the upper end of the cylindrical head body 3, a base tube portion 6 is formed in which the outer diameter is smaller than the inner diameter of the pile body 1 and the lower end of the pile body 1 is externally fitted. A bottomed cylindrical excavation head 2 having a substantially conical bottom 2a is integrally formed, and a spiral blade 4 is provided on the outer peripheral surface of the cylindrical head main body 3. A cutting blade 5 projects from the lower surface of the conical bottom 2a.

  And the base cylinder part 6 of this connection member Q is provided with a bolt insertion hole 8 at a position that matches the pile main body side bolt insertion hole 7 when the connection end of the pile main body 1 is externally fitted thereto. A nut holding portion 9 is provided on the inner peripheral surface side of the cylindrical portion 6 to hold the nut 10 at a position opposed to the base cylindrical portion-side bolt insertion hole 8 in the axial direction, and each nut holding portion 9 has an upper inlet O. A pair of holding walls 11 and 11 on both sides that restrict the rotation of the nut 10 by receiving the inserted nut 10 at the opposite position, and preventing the nut 10 from coming out from the inlet O and holding the nut 10 at the opposite position. For this reason, it is integrally provided so as to narrow the inlet O on the holding wall 11 on one side, and when inserting the nut, it is elastically deformed so as to widen the inlet O by striking the nut 10 from the inlet O, allowing insertion. After insertion, restore and nut 0 consisting of retaining arm 12. be prevented from coming off the. In addition, the structure of each nut holding part 9 is the same structure as the nut holding part 9 of the connection members N and M. Moreover, when the pile main body 1 is an electric-resistance-welded steel pipe, the groove part for accepting the weld bead 22 (refer FIG. 11) which extends in the steel pipe longitudinal direction and protrudes to the inner peripheral surface side is provided in the outer peripheral surface of the base cylinder part 6. 15 is provided in the connecting member axial direction.

  The connecting member Q may be manufactured by a lost wax method using a wax model having the same shape as that of the entire connecting member Q when the spiral blade 4 is not provided on the cylindrical head body 3. Preferably, however, the connecting member Q forms a head main body wax model having the same shape as that of the cylindrical head main body 3 by a wax model forming die and forms a base cylinder portion wax model having the same shape as the base cylinder portion 6 as a wax model. Molded with a mold, a base wax model is joined to the upper end of the head body wax model to form a connecting member wax model having the same shape as the connecting member Q, and this connecting member wax model is cast by the lost wax method. Formed by. A specific manufacturing method by the lost wax method is the same as the casting method of the connecting member N described with reference to FIGS.

  Further, when the spiral blade 4 protrudes from the cylindrical head body 3 of the connecting member Q, the connecting member Q that protrudes the spiral blade 4 from the cylindrical head body 3 protrudes from the spiral blade 4. A head body wax model with a spiral wing having the same shape as the provided cylindrical body 3 is molded with a wax model molding die, and a base cylinder wax model with the same shape as the base cylinder portion 6 is molded with a wax model molding die, Formed by joining the base cylinder wax model to the upper end of the winged head body wax model to form a connecting member wax model having the same shape as the connecting member Q, and casting the lost wax method using this connecting member wax model. If it does so, the connection member Q which has the spiral blade 4 can be manufactured easily.

  In order to assemble the multi-blade type steel pipe pile K, as shown in FIG. 14, first, the lower base cylinder portion 21 of the connecting member M is internally fitted to the upper end portion of the lower divided pile main body 1, and the bolt 13 ( 10) is inserted into the base cylinder side bolt insertion hole 8 from the pile body side bolt insertion hole 7 and screwed into the nut 10 held in the nut holding portion 9, thereby connecting the connecting member M to the lower pile. The upper base cylinder part 21 is fixed to the upper end of the main body, and then the upper base cylinder part 21 is internally fitted to the lower end part of the upper divided pile main body 1, and the bolt 13 is connected to the base cylinder from the bolt main body side bolt insertion hole 7 in the same manner as described above. The upper base tube portion 21 of the connecting member M is fixed to the upper end portion of the pile body by being inserted into the portion side bolt insertion hole 8 and screwed into the nut 10 held in the nut holding portion 9, thereby dividing the both The pile main bodies 1 and 1 are connected integrally.

  After the upper and lower pile main bodies 1 and 1 thus divided are connected via the connecting member M, a connecting member Q for connecting the excavation head 2 with the spiral blade 4 is attached to the lower end portion of the lower pile main body 1. As for the attachment of the connecting member Q, the lower end portion of the lower pile body 1 is externally fitted to the base tube portion 6 of the cylindrical head body 3, and the bolt 13 (see FIG. 10) is inserted through the pile body side bolt. The connecting member Q is attached and fixed to the lower end portion of the pile main body 1 by being inserted into the base tube portion side bolt insertion hole 8 from the hole 7 and screwed into the nut 10 held in each nut holding portion 9. Can do.

  Also when assembling the multi-blade type steel pipe pile K as described above, prior to the connection work between the pile body 1 and the connection members M and Q, the nuts 10 are inserted in advance into the nut holding portions 9 of the connection members M and Q. By doing so, the connection work between the pile body 1 and the connection members M and Q can be performed efficiently. Thus, in order to insert the nut 10 into each nut holding portion 9, the nut 10 is placed at the inlet O of the upper end side nut holding portion 9 and locked to the protruding portion 12 b of the retaining arm 12. If the nut 10 is tapped with a hammer or the like from the state, the distal end side of the retaining arm 12 with the protruding portion 12b is elastically deformed outward and the inlet O is slightly widened, so the nut 10 is inserted into the nut holding portion 9 as it is. Thus, after the insertion, the retaining arm 12 is elastically returned to the original position to prevent the nut 10 from being pulled out, and the nut 10 is held at the opposing position as the connecting member side bolt insertion hole 7. . Therefore, the connecting member N that holds the nut 10 in each nut holding portion 9 in this way does not come out of each nut holding portion 9 even if it is turned sideways or repeated upside down. It can be carried while holding the nut 10 in the nut holding part 9, and the connecting operation of the pile body 1 can be performed when necessary, so that the work efficiency can be greatly improved.

  The steel pipe pile K of the embodiment shown in FIGS. 12 to 14 is a multi-blade steel pipe pile having spiral blades 4 at the lower end portion and the intermediate portion of the pile main body 1. In the widened type with only the spiral blade 4 or the straight type steel pipe pile without the spiral blade 4 and only the excavation head 2 attached to the lower end of the pile body 1, the pile body 1 is divided into a plurality of parts. The connecting members M and Q described above can also be used when connecting the pile main bodies 1 to each other.

  If the connecting members N and M as described above are used, the long pile main body 1 can be divided into a plurality of pieces and the divided pile main bodies 1 and 1 can be easily connected to each other. When transporting to the site, if it is loaded on a truck in a short state before connection, it is easy to load, and even a relatively small truck can be carried. In particular, in the case of a steel pipe pile K having a spiral blade 4 in the middle part, if a connecting member M having a spiral blade 4 protruding from a cylindrical main body 20 is used, the pile body 1 can be used as a truck bed during transport to a construction site. And the connecting member M are stacked separately, the loading efficiency is good and the transportation cost can be reduced. The connecting member M is not limited to the case where the pile main body 1 is divided into a plurality of parts as described above and the divided pile main bodies 1 are connected to each other, and the connecting member M described with reference to FIGS. Thus, it can also be used for pile driving work in which steel pipe piles of a predetermined length are sequentially added as many as required. Of course, the connecting member M can also be used for pile driving work in which steel pipe piles of a predetermined length are successively added in the required number.

Wn Half split wax model WN Connecting member wax model K Steel pipe pile N Connecting member M Connecting member Q Connecting member O Entrance of nut holding part 1 Pile main body 2 Excavation head 3 Head main body 4 Spiral blade 6 Base cylinder part 7 Pile main body side bolt Insertion hole 8 Connecting member side bolt insertion hole 9 Nut holding portion 10 Nut 11 Holding wall 11a Vertical wall portion 11b Nut receiving wall portion 12 Retaining arm 12a Arm body portion 12b Protruding portion 13 Bolt 14 Back portion 15 of nut holding portion 9 Welding Concave groove 16 for receiving bead 16 Chamfer 20 Cylindrical body 21 Base tube 22 Weld bead

Claims (25)

  When connecting the lower end of the upper pile body to the upper end of the lower pile body, the lower half is internally fitted to the upper end of the lower pile body and the upper half is internally fitted to the lower end of the upper pile body. A cylindrical connecting member is provided, bolt insertion holes are provided at regular intervals in the upper end of the lower pile body and the lower end of the upper pile body, and the upper end side and the lower end side of the connecting member are provided. Is provided with a bolt insertion hole at a position that coincides with the pile body side bolt insertion hole when the connection member is internally fitted to the connection end of the pile body, and at the upper and lower ends of the inner peripheral surface of the connection member, A nut holding portion is provided for holding the nut at a position facing the connecting member side bolt insertion hole in the axial direction, and each nut holding portion on the upper end side receives the nut inserted from the upper inlet at the facing position. A pair of holding walls on both sides to limit the rotation of the nut and the nut from the inlet In order to prevent slipping out and hold the nut in the opposite position, it is integrally protruded so as to narrow the inlet to the holding wall on one side, and when inserting the nut, the inlet is widened by hitting the nut from the inlet A retaining arm that elastically deforms to permit insertion and restores after insertion to prevent the nut from falling off, and each nut holding part on the lower end side is vertically symmetrical with each nut holding part on the upper end side The lower half of the connecting member is fitted into the upper end of the lower pile body, and the bolt is inserted from the pile body side bolt insertion hole into the connection member side bolt insertion hole to enter the nut holding portion. By screwing onto the held nut, the connecting member is fixed to the upper end of the lower pile body, the upper half of this connecting member is fitted into the lower end of the upper pile body, and the bolt is connected to the pile main body side. From the bolt insertion hole to the connecting member side A steel pipe pile formed by integrally connecting both pile main bodies by fixing the connecting member to the lower end of the upper pile main body by screwing into the nut held in the nut holding portion through the through hole. Linked structure.   The retaining arm of each nut holding part includes an arm main body part that protrudes horizontally from the upper end on the near side of the holding wall on one side toward the opposite part of the holding wall on the opposite side, and an inner side surface of the tip part of the arm main body part. The steel pipe pile connection structure according to claim 1, comprising a protrusion that integrally projects so as to slightly narrow the inlet of the nut holding portion.   Each holding wall of each said nut holding | maintenance part consists of a vertical wall part of a planar view substantially L shape, and a nut receiving wall part which protrudes inward from the lower end part of a vertical wall part. Steel pipe pile connection structure.   The steel pipe pile connection structure according to any one of claims 1 to 3, wherein a back surface portion of a nut holding portion that is a pressure contact surface pressed by tightening a bolt screwed into the nut is a flat surface portion.   On the outer peripheral surface of the connecting member, when the pile main body to be connected is an ERW steel pipe, a concave groove portion is provided in the axial direction of the connecting member for receiving a weld bead extending in the longitudinal direction of the steel pipe and protruding toward the inner peripheral surface side. The steel pipe pile connection structure according to any one of claims 1 to 4.   The connecting member side bolt insertion holes are provided at equidistant positions in the circumferential direction of the connecting member to the left and right with respect to the concave groove, and the pile body is equidistant to the left and right of the pile body with respect to the weld bead. The connection structure of the steel pipe pile of Claim 5 in which the said pile main body side volt | bolt penetration hole is provided in the position.   The connecting member is formed by molding two wax molds having the same shape as the halves obtained by dividing the connecting member into two halves using a wax model mold, and joining the two halved solder models symmetrically. The steel pipe pile connection according to any one of claims 1 to 6, which is formed by forming a connection member wax model having the same shape as the connection member, and casting by the lost wax method using the connection member wax model. Construction.   When connecting the lower end of the upper pile body to the upper end of the lower pile body, the outer diameter of the cylindrical body having the same outer diameter as the outer diameter of the pile body is smaller than the inner diameter of the pile body. A cylindrical connecting member is formed by forming an upper and lower base cylinder portion in which the lower end portion of the upper pile body and the upper end portion of the lower pile body are respectively externally fitted, and the upper end portion of the lower pile body and the upper pile Bolt insertion holes are provided in the lower end of the main body at regular intervals in the circumferential direction, and the pile main body side bolts are inserted into the upper and lower base tube portions of the connecting member when the connecting end of the pile main body is fitted to the base tube portion. Bolt insertion holes are provided at positions that match the holes, and nut holding portions are provided on the inner peripheral surface side of the respective base tube portions to hold the nuts at positions opposed to the respective base tube side bolt insertion holes in the axial direction. Each nut holding part on the upper end side receives the nut inserted from the upper inlet at the opposite position and A pair of holding walls on both sides that restrict the rotation of the nut, and a protrusion protruding integrally with the holding wall on one side so as to narrow the inlet in order to prevent the nut from coming out of the inlet and hold the nut in the opposite position. When inserting the nut, it is elastically deformed so as to widen the inlet by striking the nut from the inlet, allowing the insertion, and after the insertion, a retaining arm that prevents the nut from being restored and inserted, each nut on the lower end side The holding part is formed symmetrically with each nut holding part on the upper end side, and the lower base tube part is fitted into the upper end part of the lower pile body, and the bolt is inserted into the pile body side bolt. The connecting member is fixed to the upper end of the lower pile body by inserting the hole from the hole into the bolt insertion hole on the base cylinder side and screwed into the nut held in the nut holding portion, and the upper base cylinder portion is fixed to the upper pile body Fitting bolts into the bottom end The upper base cylinder part is fixed to the lower end of the upper pile body by inserting the body side bolt insertion hole into the base cylinder side bolt insertion hole and screwing into the nut held in the nut holding part. Steel pipe pile connection structure that is integrally connected to each other.   The steel pipe pile connection structure according to claim 8, wherein a spiral wing projects from the cylindrical main body of the connection member.   The retaining arm of each nut holding part includes an arm main body part that protrudes horizontally from the upper end on the near side of the holding wall on one side toward the opposite part of the holding wall on the opposite side, and an inner side surface of the tip part of the arm main body part. The steel pipe pile connection structure according to claim 8 or 9, comprising a protruding portion that integrally projects so as to slightly narrow the inlet of the nut holding portion.   Each holding wall of each said nut holding | maintenance part consists of a vertical wall part of a planar view substantially L shape, and the nut receiving wall part which protrudes inward from the lower end part of a vertical wall part. Connection structure of steel pipe piles described in 1.   The steel pipe pile connection structure according to any one of claims 8 to 11, wherein a back surface portion of a nut holding portion which is a pressure contact surface pressed by tightening a bolt screwed into the nut is a flat surface portion.   The outer peripheral surface of each of the upper and lower base tube portions of the connecting member is connected with a groove portion for receiving a weld bead extending in the longitudinal direction of the steel pipe and projecting to the inner peripheral surface side when the pile body to be connected is an ERW steel pipe. The connection structure of the steel pipe pile in any one of Claims 8-12 currently provided in the member axial direction.   The base cylinder part side bolt insertion hole is provided at an equidistant position in the circumferential direction of the connecting member to the left and right with the concave groove as a base point, and the pile body has a weld bead as a base point to the left and right of the pile body in the circumferential direction, etc. The steel pipe pile connection structure according to claim 13, wherein the pile main body side bolt insertion hole is provided at a distance position.   The connecting member is formed by molding two wax molds having the same shape as the halves obtained by dividing the connecting member into two halves using a wax model mold, and joining the two halved solder models symmetrically. The steel pipe pile according to any one of claims 8 and 10 to 14, wherein the steel pipe pile is formed by forming a connecting member wax model having the same shape as the connecting member and casting the lost member using the connecting member wax model. Connection structure.   The connecting member having a spiral wing projecting from a cylindrical main body is formed by molding a cylindrical main body wax model with a spiral wing having the same shape as the cylindrical main body projecting the spiral wing by a wax model molding die. The base cylinder part wax model having the same shape as the above is molded by a wax model mold, and both base cylinder part wax models are joined symmetrically to the upper and lower ends of the cylindrical main body wax model with spiral wings in a vertically symmetrical manner. The steel pipe pile connection structure according to any one of claims 9 to 14, which is formed by forming a connecting member wax model having the same shape and casting the connecting member wax model using the lost wax method.   When connecting the excavation head to the lower end of the pile body, the outer diameter is equal to the inner diameter of the pile body at the upper end of the cylindrical head body that has the same outer diameter as the pile body and the excavation head is formed at the lower end. A cylindrical connecting member is formed which is smaller in diameter and forms a base tube part into which the lower end portion of the pile body is externally fitted. Bolt insertion holes are provided in the lower end portion of the pile body at regular intervals in the circumferential direction. The base tube portion of the member is provided with a bolt insertion hole at a position that matches the bolt main body side bolt insertion hole when the connection end of the pile main body is fitted externally to the base tube portion, and the inner peripheral surface side of the base tube portion Provided with a nut holding portion for holding the nut at a position opposed to the base tube portion side bolt insertion hole in the axial direction, and each nut holding portion receives the nut inserted from the upper inlet at the opposite position to receive the nut. A pair of holding walls on both sides that restrict rotation and the nut from coming out from the inlet is prevented. In addition, in order to hold the nut in the opposite position, it is integrally protruded so as to narrow the inlet to the holding wall on one side, and when inserting the nut, it is elastically deformed to widen the inlet by hitting the nut from the inlet. A retaining arm that allows insertion and restores after insertion to prevent the nut from being removed.The base tube portion is internally fitted to the lower end portion of the pile body, and the bolt is inserted from the bolt body side bolt insertion hole. A steel pipe pile connection structure in which a connecting member is fixed to a lower end portion of a pile body by being inserted into a base tube portion side bolt insertion hole and screwed into a nut held in a nut holding portion.   The steel pipe pile connection structure according to claim 17, wherein a spiral wing projects from the cylindrical head body of the connection member.   The retaining arm of each nut holding part includes an arm main body part that protrudes horizontally from the upper end on the near side of the holding wall on one side toward the opposite part of the holding wall on the opposite side, and an inner side surface of the tip part of the arm main body part. The connection structure of the steel pipe pile according to claim 17 or 18 which consists of a projection part which protrudes integrally so that the entrance of a nut holding part may be narrowed a little.   Each holding wall of each said nut holding part consists of a vertical wall part of a plane shape substantially L shape, and a nut receiving wall part which protrudes inward from the lower end part of a vertical wall part. Connection structure of steel pipe piles described in 1.   The connecting structure for steel pipe piles according to any one of claims 17 to 20, wherein a back surface portion of a nut holding portion that becomes a pressure contact surface that is pressed by tightening a bolt that is screwed onto the nut is a flat surface portion.   A concave groove for receiving a weld bead that extends in the longitudinal direction of the steel pipe and protrudes toward the inner peripheral surface when the pile body to be connected is an electric-welded steel pipe is provided on the outer peripheral surface of the base tube portion of the connecting member. The connection structure of the steel pipe pile in any one of Claims 17-21 currently provided in the direction.   The base cylinder part side bolt insertion hole is provided at a position equidistant in the connecting member circumferential direction to the left and right with the concave groove as a base point, and the pile body has a weld bead as a base point to the left and right with respect to the pile body circumferential direction, etc. The steel pipe pile connection structure according to claim 22, wherein the pile main body side bolt insertion hole is provided at a distance position.   The connecting member forms a head body wax model having the same shape as the cylindrical head body by a wax model molding die and a base cylinder part wax model having the same shape as the base cylinder portion by a wax model molding die. The base cylinder wax model is joined to the upper end of the main body wax model to form a connecting member wax model having the same shape as the connecting member, and the connecting member wax model is cast by the lost wax method. The connection structure of the steel pipe pile in any one of 17, 19-23.   The connecting member having a spiral wing projecting from a cylindrical head body is formed by molding a wax body with a spiral wing having the same shape as the cylindrical body projecting the spiral wing with a wax model molding die and the base tube portion. The base cylinder part wax model having the same shape as the above is molded with a wax model molding die, and the base cylinder part wax model is joined to the upper end of the head body wax model with a spiral wing to form a connecting member wax model having the same shape as the connecting member. The steel pipe pile connection structure according to any one of claims 18 to 23, wherein the steel pipe pile connection structure is formed by casting by the lost wax method using the connection member wax model.

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