JP5825232B2 - Combined steel walls and design methods for combined steel walls - Google Patents

Description

  The present invention relates to a combined steel wall used for earth retaining work, deadline work, revetment, landfill, embankment and the like.

A combination steel wall is a structure that combines a steel sheet pile with an H-section steel or steel pipe to construct a wall, and increases rigidity by combining a stiffener such as an H-section steel or steel pipe with a steel sheet pile wall. It is a structure that can be applied in areas with high wall height. Further, by constructing the wall body by fitting the steel sheet pile walls, it is possible to improve the water stoppage as compared with the steel pipe sheet pile having a relatively large gap between the joints.
Among the combined steel walls, when a steel pipe is applied as a stiffener, it has various construction advantages. When H-shaped steel is used as a stiffener, there is a problem that the flange part tends to deform due to the resistance of the ground when the H-shaped steel is driven into the ground, but in the case of a steel pipe, it protrudes like a flange of H-shaped steel. Since there is no part, stable construction is easy. Moreover, it can also be driven to the ground while rotating by using a steel pipe.
The thing of patent document 1 and patent document 2 is known as an example of the steel wall which combines a steel pipe and a steel sheet pile.

The steel wall described in Patent Document 1 is provided with a processing jig for fitting a stiffener on at least one of the front and back surfaces of a steel sheet pile, and through this processing jig, an H-shaped steel, a steel pipe sheet pile, etc. A stiffener is installed. When a steel pipe sheet pile is applied as a stiffener, a wall is formed by fitting a joint of a steel pipe sheet pile to a processing jig attached to the steel sheet pile for fitting a stiffener. Is transmitted through a steel pipe sheet pile joint.
In the steel wall described in Patent Document 2, a plurality of steel sheet piles are connected by joints to provide a wall body, and a steel pipe has its longitudinal direction on all or part of the steel sheet piles of the wall body. It touches along the longitudinal direction of this. By making it a wall body combining a steel pipe and a steel sheet pile, a steel wall having both high water-stopping properties and high rigidity can be provided.

JP-A-2005-299202 International Publication No. 2011/142047 Pamphlet

  In patent document 1 and patent document 2, the structure which skips the pitch of stiffeners, such as a steel pipe, is described as one embodiment. Depending on the rigidity and proof strength required for the wall body, a reasonable structure can be realized by selecting a suitable stiffener such as a steel pipe or H-shaped steel and combining it with a steel sheet pile. On the other hand, if the pitch is skipped too much, the wall body may show an unstable behavior, and the desired performance may not be exhibited.

Strictly speaking, the rigidity and proof stress of a wall body that combines steel sheet piles and stiffeners vary depending on the location of the stiffener and its vicinity, and the vicinity of the middle of adjacent stiffeners, but this is averaged. Assuming that the rigidity can be evaluated, it is possible to reduce the weight of the steel material to be used as the steel pipe diameter per one piece and the size of the H-shaped steel are increased and the pitch is increased.
However, as the pitch of the stiffener increases, the stiffening effect on the steel sheet pile wall does not reach evenly, and the deformation of the steel sheet pile wall increases near the middle of adjacent stiffeners. The deformation becomes non-uniform in the width direction of the wall. Furthermore, if the pitch is increased too much, the steel sheet pile near the middle of adjacent stiffeners will no longer have a stiffening effect. In other words, near the stiffener, it behaves as a highly rigid wall that combines the steel sheet pile wall and stiffener, but near the middle of the adjacent stiffeners it behaves as a steel sheet pile wall alone or close to it. It will be. In this case, the rigidity of the wall cannot be averaged and handled, and the steel sheet pile wall becomes plastic in the vicinity of the middle of adjacent stiffeners. There is a possibility that the body will not be stable and will collapse.
In the previous invention, there is no mention of a pitch range or the like in which the effect of the stiffener can be appropriately obtained for the steel sheet pile wall.

Further, in a “combination steel wall” in which a steel sheet pile wall and a stiffener are combined, the use of a steel pipe as a stiffener has various advantages in construction. When H-shaped steel is used as a stiffener, there is a problem that the flange part tends to deform due to the resistance of the ground when the H-shaped steel is driven into the ground, but in the case of a steel pipe, it protrudes like a flange of the H-shaped steel. Since there is no part, stable construction is easy. Moreover, it can also be placed on the ground while rotating the steel pipe. Furthermore, if a circular steel pipe is arrange | positioned to the corrugated recessed part of a steel sheet pile, the stiffening effect of a steel pipe will become easy to spread equally with respect to a steel sheet pile wall.
Therefore, in the present invention, the structure is limited to a combined steel wall made of a steel pipe and a steel sheet pile, and in the combined steel wall, the steel pipe is placed on the high side of the ground surface (back side) across the wall body. An indoor model test was performed on the structure in which the pitch of the steel pipe was set and the pitch of the steel pipe was skipped.

This indoor model test is as follows.
As shown in FIG. 1, an acrylic specimen K is fixed at the lower end with an adhesive in the center of a rigid earth tub D having a width of 1957 × height of 1000 × depth of 940 mm, and silica sand No. 5 (dry sand) on the left and right S was installed by the air drop method, and from this state, the excavation side was dug down to the lower end, and the behavior of the wall body (acrylic specimen K) was confirmed.

Acrylic specimen K consists of a corrugated plate K1 simulating a steel sheet pile and a pipe K2 simulating a steel pipe, and a wall is formed. Are connected.
Examine the opposite side (front side) where the steel pipe is placed, and perform the test focusing on the case where earth pressure acts from the steel pipe side, depending on the contact situation between the steel pipe and the steel sheet pile, and the presence of head coping. In order to examine the effect, the test was conducted under different conditions as summarized in the table below. In addition, even if the steel pipe and the steel sheet pile are not in contact with each other (case (3)), the center position of the steel sheet pile wall coincides with the outer periphery of the steel sheet pile so that a part of the steel pipe enters the concave portion of the steel sheet pile wall. In any case, the steel pipe is installed so that a part of the steel pipe enters the recess of the steel sheet pile wall. In the test, the steel pipe is sandwiched between two adjacent steel pipes, including the steel pipe arranged on the opposite side of the sheet pile placed in the center of the soil layer, and the steel pipe placed adjacent to the center of the steel sheet pile. A strain gauge was attached to the center of the web at the intermediate position, and the strain generated by excavation was measured.
Moreover, in the steel pipe arrange | positioned in the center part, the jig for displacement measurement was attached to the upper part of the steel pipe, and the displacement of the head was measured in the position of 1050 mm from the lower end.

  The distribution in the depth direction of the vertical strain generated in the steel pipe in each case is shown in FIG. The strain generated in the steel pipe (pipe K2) in the graph is positive on the tension side. In the graph, the strain calculated when assuming that the steel pipe (pipe K2) is a cantilever with a fixed lower end and the whole earth pressure acts is also shown. Regarding the earth pressure for strain calculation at that time, the same test was separately performed using only a steel sheet pile (corrugated board K1), and the earth pressure was calculated from the result. Table 2 shows the displacement measured at a position of 1050 mm from the lower end of the steel pipe arranged at the center.

  From FIG. 2, the vertical strain generated in the steel pipe shows the same behavior as in the case where it is assumed that the whole earth pressure is applied to the steel pipe (pipe K2) in any case. In addition, as shown in Table 2, the displacement of the steel pipe is almost the same regardless of the case, regardless of the contact condition between the steel sheet pile (corrugated plate K1) and the steel pipe (pipe K2), and the presence or absence of coping. However, it is thought that the behavior of the whole earth pressure acting on the steel pipe was shown.

  The distribution in the depth direction of the vertical strain generated in the steel sheet pile at the intermediate position between adjacent steel pipes in each case is shown in FIG. The strain generated in the steel sheet pile (corrugated plate K1) in the graph is also shown for the strain calculated with the compression side as positive and the steel sheet pile (corrugated plate K1) as a cantilever with a fixed lower end. In addition, about the earth pressure considered in calculation, as shown in FIG. 4, when the pitch of a steel pipe is set to L, the diameter of a steel pipe is set to D, and the length of the part which does not overlap with a steel pipe is set to (LD), it shows in FIG. Thus, when the earth pressure of the triangular distribution of (LD) / L · p (converted earth pressure for the width) acts on the earth pressure of the triangle distribution with the deepest load acting on the wall as p Assumes.

From FIG. 3, when the steel pipe and the steel sheet pile are not connected at the head, the earth pressure acting on the length (LD) of the portion that does not overlap with the steel pipe is considered to be equal to the pitch L of the steel pipe (for the width). ), The vertical strain distribution of the steel sheet pile at the intermediate position between adjacent steel pipes can be expressed.
On the other hand, when the steel pipe and the steel sheet pile are connected at the head, a bending moment in the direction opposite to the wall deep portion is generated in the shallow wall portion of the steel sheet pile wall. This is presumably because the steel sheet pile shows a behavior supported by a steel pipe at the head. Therefore, as shown in FIG. 6, the strain generated in the vertical direction was calculated assuming that the steel sheet pile wall considered as a cantilever fixed at the lower end was further simply supported in the horizontal direction by the head. FIG. 7 shows the results and the distribution in the depth direction of the vertical strain measured in each case. As for the earth pressure considered in the calculation, the equivalent earth pressure corresponding to the width is taken into consideration as described above.

  From FIG. 7, when the steel pipe and the sheet pile are connected at the head (cases (2) and (3)), the vertical strain distribution of the steel sheet pile at the intermediate position between the adjacent steel pipes is as follows. Considering the earth pressure acting on the length (LD) of the part that does not overlap with the steel pipe as the beam with the head simply supported by fixing the lower end to the pitch L of the steel pipe (considering the equivalent earth pressure for the width) It shows a tendency to become slightly larger in the positive direction than the calculated value. Here, the reason why the experimental value shows a larger value in the positive direction in the strain distribution than the calculated value is thought to be because the restraint at the head is reduced due to the displacement of the steel pipe. In addition, when the calculated value and the experimental value when the head is set free are compared, the experimental value shows a smaller value due to deeper strain.

As mentioned above, in the combination steel wall of the steel pipe and the steel sheet pile, when the steel pipe is arranged on the high side (back side) with the wall in between and the head of the steel pipe and the steel sheet pile is connected, Although the support conditions differ depending on the size of the steel sheet pile restraint due to, the vertical strain distribution of the steel sheet pile at the middle position between adjacent steel pipes is the same as when the head is freed with the steel sheet pile wall as a single fixed beam. The behavior during simple support is shown. At that time, a part of the steel pipe is installed in the concave part of the steel sheet pile wall, so that it seems that the earth pressure acting on the steel sheet pile is reduced, the pitch of the steel pipe is L, the steel pipe If the diameter is D and the length of the part that does not overlap with the steel pipe is (LD), it can be roughly expressed by applying earth pressure (converted earth pressure for the width) of (LD) / L times. ing.
As shown in FIG. 6, when a steel sheet pile wall is fixed at the lower end and the beam is simply supported by the head, the bending that occurs in the steel sheet pile when (LD) / L times earth pressure is applied. The maximum value M _{sfmax of the} moment is obtained by the following equation (1).

Ｍ_{ｓｆｍａｘ}：下端固定・頭部単純支持の梁に作用する曲げモーメントの最大値
ｐ：三角形分布荷重の最大値
Ｌ：鋼管のピッチ
Ｄ：鋼管径
Ｈ：壁の高さ

M _sfmax : Maximum value of the bending moment acting on the beam with the lower end fixed and the head simply supported p: Maximum value of the triangular distributed load L: Steel pipe pitch D: Steel pipe diameter H: Wall height

Therefore, the maximum value M _sfmax of the bending moment generated when the earth pressure of ( _LD ) / L times is applied assuming that the steel sheet pile wall is fixed at the lower end and the head is simply supported. Figure 6 using the maximum when the load of the deepest, as shown in (a) were considered triangular distributed load to p acts on wall bending moment Mmax (= pH ^2/6) the following equation (2) of It is expressed as follows.

Ｍｍａｘ：壁体に発生する最大曲げモーメント（＝ｐＨ^２／６）
前述した通り、鋼管と鋼矢板との組み合わせ鋼製壁において、壁体を挟んで地盤面の高い側（背面側）に鋼管を配置し、鋼管と鋼矢板の頭部を連結した場合には、隣り合う鋼管の中間位置における鋼矢板の鉛直挙動は、鋼矢板壁単体を下端固定の梁として、頭部を自由にした場合と、単純支持した場合の間の挙動を示す。したがって、図５（ａ）及び図６（ａ）に示すように壁体に最深部の荷重をpとする三角形分布荷重が作用する場合、鋼管から最も離れた位置で鋼矢板に発生する曲げモーメントの最大値M_smaxは下記（３）式で表わされる。

Mmax: maximum bending moment generated in the wall (= ^pH 2/6)
As described above, in the combined steel wall of steel pipe and steel sheet pile, when placing the steel pipe on the high side (back side) of the ground surface across the wall, and connecting the head of the steel pipe and steel sheet pile, The vertical behavior of the steel sheet pile at an intermediate position between adjacent steel pipes shows the behavior between the case where the steel sheet pile wall itself is a beam fixed at the lower end and the head is freed and the case where it is simply supported. Therefore, as shown in FIGS. 5 (a) and 6 (a), when a triangular distributed load with the deepest load p is applied to the wall, the bending moment generated in the steel sheet pile at the position furthest away from the steel pipe. The maximum value M _{smax of} is expressed by the following equation (3).

Ｍｓｍａｘ：隣り合う鋼管の中間付近の鋼矢板に発生する曲げモーメントの最大値
Ｌ：鋼管のピッチ
Ｄ：鋼管径
Ｍｍａｘ：壁体に発生する最大曲げモーメント（＝ｐＨ^２／６）

MSmax: maximum value of the bending moment generated in the steel sheet pile near the middle of the adjacent steel pipe L: the pitch D of the steel pipe: steel pipe size Mmax: maximum bending moment generated in the wall (= ^pH 2/6)

From the above, as the pitch of the steel pipe is increased, the bending moment generated in the steel sheet pile at the intermediate position between the adjacent steel pipes increases, but if (LD) /L≦0.9 is established, the middle of the adjacent steel pipes. The steel sheet pile at the position also has an effect of reducing the bending moment of about 10% to 60% compared to the case where the steel sheet pile wall is used alone, and the material of the steel sheet pile can be dropped in practice or a material with low strength can be selected. It is thought that the effect is seen. Currently, there are steel sheet pile types generally used as shown in Table 3, for example. For example, the section modulus of 10H is 56% of the section modulus of 25H, and the section modulus of IVw is 86% of the section modulus of VL. If the bending moment can be reduced by about 10% to 40%, the steel sheet pile of lower model There is a possibility that can be selected. In general, two types of yield strengths of 295 N / mm ² and 390 N / mm ² are used. If the bending moment can be reduced by about 25% or more, a steel sheet pile having a lower yield strength may be applicable. .

From the above, it can be considered that if (LD) /L≦0.9 is established with respect to the pitch L and the steel pipe diameter D of the steel pipe, the steel pipe has a stiffening effect over the width direction of the wall body.
Therefore, if the pitch L of the steel pipe satisfies the following formula (4), the effect of reducing the generated stress of the steel sheet pile near the middle of the adjacent steel pipes and combining with the steel pipes can be seen. That is, the stiffening effect of the steel pipe can be exhibited over the width direction of the wall body.
L ≦ 10D (4)

  Next, in the case where the steel pipe is set to ensure safety and soundness, a study is made from the viewpoint that the wall body secures safety and soundness over the width direction of the wall body. For the steel sheet pile wall, the stiffening effect of the steel pipe against the steel sheet pile is minimized near the middle of the adjacent steel pipes, and a large stress is generated at that portion. As described above, when steel pipes are arranged on the high ground side (back side) across the wall, and the steel pipe pitch is L and the steel pipe diameter is D, the stress of the steel sheet pile near the middle of the adjacent steel pipes Is smaller than the stress generated when the earth pressure of (LD) / L times of the whole is applied with a steel sheet pile wall as a cantilever as shown in FIG. That is, the following formula (5) is established.

Ｍｓｍａｘ：隣り合う鋼管の中間付近の鋼矢板に発生する最大曲げモーメント
σ_s：隣り合う鋼管の中間付近の鋼矢板に発生する最大応力
Ｚ_ｓ：鋼矢板壁の壁幅１ｍあたりの断面係数
Ｌ：鋼管のピッチ
ｐ：三角形分布荷重の最大値
Ｄ：鋼管径
Ｍｍａｘ：壁体に発生する最大曲げモーメント

Msmax: Maximum bending moment generated in a steel sheet pile near the middle of adjacent steel pipes
σ _s : Maximum stress generated in the steel sheet pile near the middle of adjacent steel pipes
Z _s : Section modulus per 1m wall width of steel sheet pile wall
L: Steel pipe pitch
p: Maximum value of triangular distribution load
D: Steel pipe diameter
Mmax: Maximum bending moment generated in the wall

  If the right side of equation (5) is equal to or less than the yield stress σy of the steel sheet pile, the steel pipes are arranged on the high side (back side) across the wall and the pitch of the steel pipes is L. The maximum stress generated in the steel sheet pile near the middle of is less than the yield stress σy. That is, if Formula (6) or Formula (7) is established, the steel sheet pile will not yield over the width direction of the wall body, and safety and soundness as the wall body can be ensured.

σ_y：鋼矢板の降伏応力

σ _y : Yield stress of steel sheet pile

  From the above, it is a “combination steel wall” that combines a steel pipe and a steel sheet pile, and the steel pipe is placed on the high side of the ground surface (front side) across the wall, and the steel pipe enters the recess of the steel sheet pile. If the formula (4) and the formula (6) or (7) are established with respect to the pitch L of the steel pipe, the generated stress of the steel sheet pile near the middle of the adjacent steel pipes is reduced. The steel sheet pile does not yield over the width direction of the wall body, and safety and soundness as the wall body can be secured.

In order to achieve the above object, a combination steel wall according to claim 1 of the present application is provided with a wall body by connecting a plurality of steel sheet piles by joints, and a plurality of steel pipes on the back side with respect to the wall body. A part of the steel pipe of the steel sheet pile wall has a predetermined pitch in the width direction of the wall body so that its longitudinal direction is substantially parallel to the longitudinal direction of the steel sheet pile (on the high side of the ground surface across the wall body). It is arranged so as to enter the recess, and is a combined steel wall in which the steel pipe and the steel sheet pile are connected using a connecting member at the head,
When the pitch of the steel pipe of the wall body is L and the steel pipe diameter is D, L ≦ 10D ,
The yield stress of the steel sheet pile is σy, the section modulus per 1 m wall width of the steel sheet pile wall is Zs,
When the maximum bending moment acting on the wall is Mmax, the pitch of the steel pipe is set so that the following expression (7) is established .
By setting L ≦ 10D, the strain generated in the steel sheet pile near the middle between adjacent steel pipes can be reduced as compared to the case of only the steel sheet pile, and the effect of combining the steel pipe and the steel sheet pile can be exhibited.
The method for designing a combined steel wall according to claim 2 of the present application is as follows:
A plurality of steel sheet piles are connected by a joint to provide a wall body, and a plurality of steel pipes sandwich the wall body with respect to the wall body, and the longitudinal direction of the steel sheet pile is substantially the same as the longitudinal direction of the steel sheet pile. A combination in which the steel sheet pile and the head of the steel pipe are connected to each other so that a part of the steel pipe enters the concave portion of the steel sheet pile wall at a predetermined pitch in the width direction of the wall body. A method for designing a steel wall,
When the pitch of the steel pipe of the wall body is L and the steel pipe diameter is D, L ≦ 10D,
The yield stress of the steel sheet pile is σy, the section modulus per 1 m wall width of the steel sheet pile wall is Zs,
When the maximum bending moment acting on the wall is Mmax, the pitch of the steel pipe is set so that the following expression (7) is satisfied .

（７）式が成立することで、壁体の幅方向にわたって鋼矢板が降伏することはなく、壁体としての安全性、健全性を確保できる。

Since the formula (7) is established, the steel sheet pile does not yield over the width direction of the wall body, and safety and soundness as the wall body can be ensured.

  According to the present invention, a “combined steel wall” is a combination of a steel pipe and a steel sheet pile, and the steel pipe is disposed on the high side (back side) of the ground surface across the wall, and a part of the steel pipe is made of steel. In the structure that has entered the recess of the sheet pile, the steel sheet pile yields over the width direction of the wall body while reducing the generated stress of the steel sheet pile near the middle of adjacent steel pipes and exhibiting the effect of combining with the steel pipe There is nothing, and safety and soundness as a wall can be secured.

The laboratory model testing apparatus implemented in order to examine about the pitch of the steel pipe of the steel wall which concerns on this invention is shown, (a) is a top view, (b) is a sectional side view. It is for demonstrating the test result by the indoor model test apparatus shown in FIG. 1, and is a graph which shows the strain distribution of the perpendicular direction of the steel pipe in each case. It is a graph which shows the strain distribution of the perpendicular direction of the steel sheet pile in the intermediate position of the steel pipe which adjoins the case (1) which has not connected the steel pipe and the steel sheet pile. It is the figure which showed typically the state in which earth pressure is acting on steel walls. It is the figure which showed typically the calculation method to which the equivalent earth pressure for a width | variety ((L-D) / L times of total earth pressure) acts on the assumption that a steel sheet pile wall single-piece | unit is a beam fixed to a lower end. The calculation method for applying the equivalent earth pressure for the width ((L-D) / L times the total earth pressure) assuming that the steel sheet pile wall is a beam with a fixed bottom and a simple head is shown. FIG. Same as above, vertical strain distribution in laboratory model test, and equivalent earth pressure of width (LD of total earth pressure) assuming steel sheet pile wall as a beam fixed at the lower end and a beam fixed at the lower end and simply supported at the head. It is a graph which shows the comparison with the calculated value at the time of making / L times act. It shows an example of embodiment of the steel wall which concerns on this invention, (a) is a schematic plan view of the principal part, (b) is the same sectional side view, (c) is the head of a steel pipe and a steel sheet pile It is a schematic plan view of the principal part which shows the example connected by welding a steel plate.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 8 is an example of a combined steel wall according to the first embodiment of the present invention.
As shown in FIG. 8, the steel wall 3 of this embodiment is configured by combining a hat-shaped steel sheet pile 1 and a steel pipe 2 as steel sheet piles. A steel pipe 2 is in contact with the longitudinal direction of the hat-shaped steel sheet pile 1 along the longitudinal direction, and the steel pipe 2 is arranged on the back side (the side with the higher ground surface across the wall).

  The hat-shaped steel sheet pile 1 extends to the left and right in parallel with the web 1a from the front end of the web 1a, a pair of flanges 1b extending obliquely so as to spread from both side edges of the web 1a, and the left and right flanges 1b. A pair of arms 1c and a joint 1d provided at the tip of the arm 1c are provided. The steel pipe 2 is in contact with the web 1a in a state where the steel pipe 2 partially enters the recess of the hat-shaped steel sheet pile 1, and is connected by concrete installed across the head of the steel pipe and the steel sheet pile.

  In addition, if a steel pipe is made into the state which entered into the recessed part of the steel sheet pile wall, a steel sheet pile and a steel pipe may be installed apart. When installed remotely, the construction noise and vibration are suppressed, the steel sheet pile and the steel pipe do not contact and deform during construction, and the steel sheet pile does not contact the steel pipe. The construction method can also be adopted. Moreover, since the steel sheet pile and the steel pipe are installed apart from each other without installing fitting jigs and joints, it is possible to apply a rotary press-fitting method in which the steel pipe is rotated and driven. In addition, when steel pipes are driven by skipping the pitch of the steel pipe, if a reaction force is taken from a plurality of already-placed steel pipes and the steel pipe is to be constructed by hydraulic press-fitting or rotary press-fitting, the gripping device for the reaction force will increase. Because the distance between the steel pipe that takes the reaction force and the steel pipe to be cast becomes long, the construction becomes unstable.In that case, by gripping the cast steel sheet pile and taking the reaction force from there Even if the pitch of the steel pipe is skipped, stable placement is possible.

  In addition, as a connecting member that connects a steel pipe and a steel sheet pile, concrete installed across both the steel sheet pile and the steel pipe, a steel sheet or a reinforcing bar attached to both the steel sheet pile and the steel pipe by welding, bolts, or drill screws Or any combination can be used. In addition, if the shear displacement in the vertical direction between the steel sheet pile and the steel pipe is suppressed by welding connection or concrete, it will be possible to improve the rigidity and proof stress of the wall body, reducing the displacement of the wall body. It is possible to select a combination of a steel pipe and a steel sheet pile that is safer and more economical. Moreover, if it is a head, it will be easy to perform a connection operation | work after driving a steel sheet pile and a steel pipe separately.

The steel wall 3 shown in FIG. 8 does not have a structure in which the steel pipes 2 are installed along all the hat-shaped steel sheet piles 1, and as shown in FIG. It has a structure in which one steel pipe 2 is arranged for two steel sheet piles 1 and, as shown in FIG. 8 (b), concrete is installed and connected to the head so as to straddle the steel pipe and the steel sheet pile. Yes. Moreover, as shown in FIG.8 (c), a steel pipe may be arrange | positioned so that the joint part of the hat-shaped steel sheet pile 1 may be faced, and it connects by welding a steel plate to the head of a steel pipe and a steel sheet pile.
From the required rigidity of the steel wall 3, if the diameter, thickness, pitch, etc. of the steel pipe are set as required, the pitch of the steel pipe 2 is L, and the height of the steel wall 3 is H, L ≦ 10D What is necessary is just to set the pitch of a steel pipe so that it may become.

For example, the wall height H of the steel wall 3 is 5000 mm, the steel pipe diameter is 800 mm, the load due to earth pressure is triangular distribution, the load p at the lower end is 27 kN · m ² , and the yield stress σa of the steel sheet pile is 295 N / mm ² In this case, if the pitch of the steel pipe is 1800 mm, the formulas (1) and (4) are also satisfied, so the effect of reducing the generated stress of the steel sheet pile near the middle of the adjacent steel pipes and combining with the steel pipe The steel sheet pile does not yield over the width direction of the wall body, and safety and soundness as the wall body can be secured.

  In addition, in this Embodiment, although the structure which arrange | positions one steel pipe 2 with respect to two pieces of the hat-shaped steel sheet piles 1 was shown, this invention is not restricted to this, It is conditional on satisfy | filling (1) Formula. In addition, the pitch of the steel pipe 2 can be set as appropriate. Moreover, it is good also as a combination using not only a hat-shaped steel sheet pile but a U-shaped steel sheet pile, a Z-shaped steel sheet pile, and a linear steel sheet pile.

1 Hat-shaped steel sheet pile (steel sheet pile)
2 Steel pipe 3 Steel wall 4 Wall body

Claims (2)

A plurality of steel sheet piles are connected by a joint to provide a wall body, and a plurality of steel pipes sandwich the wall body with respect to the wall body, and the longitudinal direction of the steel sheet pile is substantially the same as the longitudinal direction of the steel sheet pile. A combination in which the steel sheet pile and the head of the steel pipe are connected to each other so that a part of the steel pipe enters the concave portion of the steel sheet pile wall at a predetermined pitch in the width direction of the wall body. A steel wall,
When the pitch of the steel pipe of the wall body is L and the steel pipe diameter is D, L ≦ 10D ,
The yield stress of the steel sheet pile is σy, the section modulus per 1 m wall width of the steel sheet pile wall is Zs,
A combined steel wall, wherein the pitch of the steel pipe is set so that the following equation (7) is established, where Mmax is the maximum bending moment acting on the wall.

A plurality of steel sheet piles are connected by a joint to provide a wall body, and a plurality of steel pipes sandwich the wall body with respect to the wall body, and the longitudinal direction of the steel sheet pile is substantially the same as the longitudinal direction of the steel sheet pile. A combination in which the steel sheet pile and the head of the steel pipe are connected to each other so that a part of the steel pipe enters the concave portion of the steel sheet pile wall at a predetermined pitch in the width direction of the wall body. A method for designing a steel wall,
When the pitch of the steel pipe of the wall body is L and the steel pipe diameter is D, L ≦ 10D,
Σy the yield stress of the previous Symbol steel sheet pile, Zs the section modulus per wall width 1m of steel sheet pile wall,
Maximum bending when the moment and Mmax, the design method of a combination steel wall and sets the pitch of the steel pipe as the lower SL (7) is established to act on the wall.

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