Underground wall, construction method thereof and formwork panel used therein
By using synthetic resin foam formwork panels, the problems of difficult sheet pile extraction and formwork corrosion and deterioration were solved, enabling low-cost and efficient underground wall construction while maintaining the long-term strength and construction efficiency of the structure.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DDP SPECIALTY ELECTRONICS MATERIALS US LLC
- Filing Date
- 2024-07-11
- Publication Date
- 2026-04-17
AI Technical Summary
In existing technologies, the sheet pile extraction process requires heavy equipment and space, and the external formwork, cross bracing, and columns are costly, prone to corrosion and deterioration, affecting the strength of the underground wall and the construction cost.
Synthetic resin foam formwork panels are used to form an underground wall by joining the sheet piles at their ends in the width direction and penetrating the soil, sealing the recessed parts with synthetic resin foam formwork, and combining them with concrete walls.
It reduces the cost of concrete formwork, prevents formwork from deteriorating over time, maintains the strength and structural integrity of the underground wall, and improves construction efficiency.
Smart Images
Figure CN121889558A_ABST
Abstract
Description
[Technical Field] The present invention relates to underground walls constructed around underground structures, methods for constructing such underground walls, and template panels for such underground walls. [Background Technology] Conventionally, when constructing an underground structure, retaining walls are formed by inserting sheet piles around the area where the underground structure is to be constructed, thereby providing support against soil pressure from the surrounding environment, and then the soil inside the retaining wall is excavated and concrete is poured inside the retaining wall (on the side of the underground structure) to form a concrete wall, thereby constructing the underground wall (see Patent Document Article 1).
[0003] [List of Citations] [Patent Literature] [PTL 1] Japanese Unexamined Patent Publication No. 2010-270442 [Summary of the Invention] [Technical Issues] Sheet piles have a generally cap-shaped cross-section in the width direction and are provided with protruding portions. The retaining wall is formed by alternately arranging sheet piles with protruding portions facing the underground structure and sheet piles facing the opposite side of the underground structure, and connecting their width-direction end portions together. Therefore, in the retaining wall, a recessed portion with a depth approximately twice the height of the protruding portion of the sheet pile is open on the underground structure side. When forming a concrete wall adjacent to the retaining wall, to prevent concrete from seeping into the recessed portion and to increase the amount of concrete poured, an outer formwork is attached to the entire retaining wall, thereby covering the recessed portion. Cross braces and supports are arranged between the outer formwork and the bottom portion of the recessed portion, allowing the outer formwork to withstand the pressure of the concrete.
[0004] Sheet piles that form retaining walls are typically extracted and removed after the underground wall has been constructed. However, extraction requires heavy equipment and a certain amount of space. Furthermore, if sheet piles are extracted, cavities are created in the soil, posing a risk of subsidence of the surrounding soil and potential impact on adjacent structures. For this reason, when constructing an underground wall, it is necessary to determine in advance the portions of the sheet piles that will be extracted and the portions that will remain embedded.
[0005] If the sheet piles are not removed, the external formwork, braces, and supports used during concrete pouring also remain embedded. These components are made of wood, and due to rising prices in recent years, they are not recyclable, significantly impacting the construction cost of the underground wall. Furthermore, there is a risk that the wooden external formwork, braces, and supports may deteriorate over time due to corrosion, and there is also a risk of gaps forming between the retaining wall and the concrete wall, reducing the strength of the underground wall.
[0006] The present invention addresses these problems, and the object of the present invention is to provide an underground wall with embedded retaining walls that can be constructed relatively inexpensively and is not easily deteriorated over time, as well as a method for constructing the underground wall.
[0007] [Solution to the problem] A first aspect of the present invention provides a perimeter wall surrounding an underground structure, characterized in that it comprises: A retaining wall is formed by joining multiple sheet piles, each having a protruding portion, together at their end portions in the width direction and penetrating the sheet piles into the soil such that the protruding portions alternately face opposite directions in the horizontal direction. A synthetic resin foam body is fitted between two sheet piles having protrusions facing the underground structure side, and closes the opening of the sheet pile having protrusions facing the side opposite to the underground structure side; and A concrete wall is arranged to contact sheet piles having projecting portions facing the underground structure side.
[0008] A second aspect of the present invention provides a method for constructing an underground wall for use in the above-described aspects of the present invention, the method comprising: The steps for forming a retaining wall are as follows: multiple sheet piles, each having a protruding portion, are joined together at their end portions in the width direction, and these sheet piles are driven into the soil such that the protruding portions alternately face opposite directions in the horizontal direction. The steps involved in excavating soil between a retaining wall and an underground structure. The step of assembling a formwork panel between two sheet piles having a protrusion facing the underground structure side to close the opening of the sheet pile having a protrusion facing the side opposite to the underground structure side. The steps for setting the internal formwork at a predetermined distance on the underground structural side of the retaining wall, and The step used to pour concrete between the retaining wall and the internal formwork. The template panel includes at least synthetic resin foam.
[0009] A third aspect of the present invention provides a template panel for use in underground walls as described above in the present invention, characterized in that, In a retaining wall formed by joining multiple sheet piles, each having a protruding portion, to each other at their width-direction end portions such that the protruding portions alternately face opposite directions in the horizontal direction, the formwork panel has a cross-sectional shape that can be fitted between two sheet piles having protruding portions facing the underground structure side, and includes at least synthetic resin foam.
[0010] [Advantages of the Invention] In this invention, by using synthetic resin foam as formwork on the side of the retaining wall during concrete pouring, the cost of concrete formwork and the costs associated with formwork installation can be significantly reduced. Furthermore, synthetic resin foam is less prone to deterioration over time due to corrosion or other factors after embedding, thus eliminating the risk of gaps forming between the retaining wall and the concrete wall over time, and extending the period for which the strength of the underground wall can be maintained. [Image Description] Figure 1 This is a schematic cross-sectional view of the sheet pile used in this invention in the width direction.
[0012] Figure 2 It is by Figure 1 A schematic cross-sectional view of a retaining wall composed of sheet piles in the horizontal direction.
[0013] Figure 3 This is a schematic cross-sectional view in the horizontal direction of an embodiment of the underground wall of the present invention.
[0014] Figure 4 It is a schematic cross-sectional view in the horizontal direction, showing the construction... Figure 1 Methods for building underground walls.
[0015] Figure 5 It is a schematic cross-sectional view in the horizontal direction, showing the construction... Figure 1 Methods for building underground walls.
[0016] Figure 6 It is a schematic cross-sectional view in the horizontal direction, used to explain the shape and size of the retaining wall and formwork panel according to the invention.
[0017] Figure 7 This is a schematic cross-sectional view in the horizontal direction of an example of a construction of an underground wall with an insulation layer.
[0018] Figure 8 This is a schematic cross-sectional view in the width direction, illustrating an application example of the template panel of the present invention.
[0019] Figure 9 This is a schematic cross-sectional view in the horizontal direction, showing an application example of the template panel of the present invention already assembled into a retaining wall.
[0020] Figure 10 This is a schematic cross-sectional view of the central portion in the width direction and the vertical direction of the template panel of the present invention, which has a support portion or a recessed portion.
[0021] Figure 11This is a schematic cross-sectional view of the central portion of a template panel in the width direction in the vertical direction, illustrating a method for connecting multiple template panels in the vertical direction.
[0022] Figure 12 It is a schematic cross-sectional view in the horizontal direction, showing the conventional methods used to construct underground walls. [Detailed Implementation] The underground wall of the present invention is a structure surrounding an underground structure to prevent soil pressure from the surrounding soil from being transmitted to the underground structure and to prevent groundwater infiltration. The underground wall of the present invention is characterized by comprising a retaining wall and a concrete wall adjacent to the retaining wall on the side of the underground structure, wherein the retaining wall is composed of multiple sheet piles, and recessed portions are sealed using synthetic resin foam. The present invention will now be described in detail.
[0024] The sheet piles used in this invention are elongated members that penetrate into the soil and are used for soil retention, and in this invention, sheet piles made of steel plates (referred to as steel sheet piles) are preferably used. Figure 1 An embodiment of it is illustrated schematically. Figure 1 This is a schematic cross-sectional view of sheet pile 10 in the width direction, as shown below. Figure 1 As shown, the sheet pile is perpendicular to... Figure 1 The component is an elongated member in the direction of the page and includes a protrusion 11 and flange portions 12, 12 at both ends of the opening portion of the recessed portion 14 within the protrusion 11. The cross-section in the width direction substantially exhibits a cap shape, and the end portions of the flange portions 12 are rolled up toward the protrusion 11 to form a joint portion 13.
[0025] Figure 2 Through links Figure 1 A schematic cross-sectional view in the horizontal direction of the retaining wall 20 formed by three sheet piles 10, where the side indicated by the arrow is the underground structure side. Figure 2 middle, Figure 1 The sheet pile with the opening of the recessed portion 14 facing the underground structure is indicated by 10a, and the sheet pile with the protruding portion 11 facing the underground structure is indicated by 10b. A retaining wall 20 with recesses and protrusions in the horizontal direction is formed by alternately connecting the sheet piles 10a and 10b via joint portions 13a and 13b. Reference numeral 21 in the figures indicates the gap between the left and right sheet piles 10b connected to the sheet pile 10a, and together with the recess 14 of the sheet pile 10a, constitutes the recessed portion of the retaining wall 20 that faces the underground structure.
[0026] Figure 3 This is a schematic cross-sectional view in the horizontal direction, showing the structure of an embodiment of the underground wall 50 of the present invention, wherein the concrete wall 40 is formed on a surface composed of... Figure 1 On the underground structure side (the side indicated by the arrow) of the retaining wall 20 composed of sheet piles 10. Figure 3 In the figures, reference numeral 30 denotes the template panel of the invention discussed below.
[0027] like Figure 2 As shown, sheet piles 10a and 10b are inserted into the soil while being connected, with the protruding portions 11a and 11b alternately facing opposite directions in the horizontal direction to form a retaining wall 20. Next, the soil between the retaining wall 20 and the area where the underground structure will be constructed is excavated, exposing the underground structural side of the retaining wall 20, except for its lower portion. Concrete is then poured onto the underground structural side of the retaining wall 20 to form a concrete wall 40, thus completing the underground wall 50. The underground structure is then constructed within the area surrounded by the underground wall 50.
[0028] Here, we will refer to Figure 12 Describe the conventional methods used to construct underground walls. Figure 12 This is a schematic cross-sectional view in the horizontal direction, where the side indicated by the arrow is the underground structure side. First, as... Figure 12 (a) As shown, attaching external template 61 to Figure 2 The retaining wall 20 is closed off from the underground structural side by the recessed portion (14, 21) of the retaining wall 20. To withstand concrete pressure, a cross brace 62 extending along the outer formwork 61 is attached to the recessed portion (14, 21) side of the outer formwork 61, and a support column 63 is attached at multiple locations perpendicular to the formwork to the rear surface between the cross brace 62 and the protruding portion 11a of the sheet pile 10a. The outer formwork 61 is attached to the entire surface of the retaining wall 20, contacting the surface of the protruding portion 11b of the sheet pile 10b on its underground structural side. Additionally, an inner formwork 64 is positioned on its underground structural side at a predetermined distance from the outer formwork 61.
[0029] Next, as Figure 12 (b) shows that concrete is poured between the outer formwork 61 and the inner formwork 64 to form a concrete wall 40. After the concrete wall 40 has been formed, the inner formwork 64 is removed.
[0030] In this invention, template panel 30 is used instead of... Figure 12 The external template 61 shown is for reference. Figure 4 and Figure 5 A method for constructing underground walls according to the present invention is described. Figure 4 and Figure 5 It is a schematic cross-sectional view in the horizontal direction, where the side indicated by the arrow is the underground structure side. Further, in the accompanying drawings, the same reference numerals are used to denote... Figures 1 to 3The components are the same as those in the text.
[0031] Prepare template panel 30, the template panel having a similar shape to... Figure 2 The cross-sectional shape corresponding to the cross-sectional shape of the gap 21 between sheet piles 10b, 10b in the recessed portion (14, 21) of the retaining wall 20. Figure 4 (a)). Then, the template panel 30 is pushed and fitted between the sheet piles 10b, 10b, thereby closing the opening of the recessed portion 14 of the sheet pile 10a. Figure 4 (b)). The inner template 64 is placed at a predetermined distance from the protruding portion 11b of the sheet pile on the underground structural side surface ( Figure 5 (a) Concrete is poured between the inner formwork 64 and the protruding portion 11b of the formwork panel 30 and the sheet pile 10b to form a concrete wall 40. Figure 5 (b)). If the internal formwork 64 is removed after the concrete wall 40 has been formed, then... Figure 3 The underground wall 50, retaining wall 20, formwork panel 30 and concrete wall 40 are integrated into the underground wall structure.
[0032] In this invention, the formwork panel 30 comprises at least synthetic resin foam and can therefore be easily attached to the retaining wall 20 by fitting it between the sheet piles 10b, 10b. Thus, the outer formwork 61, cross braces 62, and supports 63 are attached... Figure 12 Compared to conventional methods, the workability is significantly improved. Furthermore, the formwork panel 30 is lightweight, easy to handle, and has excellent workability. Additionally, because the formwork panel 30 is made of synthetic resin, it is less prone to deterioration over time, and there is no risk of gaps forming between the formwork panel 30 and the concrete wall 40, which would otherwise reduce the strength of the underground wall 50.
[0033] Next, the template panel 30 of the present invention will be described. Figure 6 This is a schematic cross-sectional view of the retaining wall 20 and the formwork panel 30 in the horizontal direction (the width direction of the sheet piles 10a and 10b and the formwork panel 30) before the formwork panel 30 has been attached to the retaining wall 20. The side indicated by arrow A is the underground structure side. It should be noted that in the following description, for convenience, the sheet piles will be referred to as sheet piles 10a or 10b, but sheet piles 10a and 10b have the same shape and dimensions.
[0034] The protruding portion 11a of the sheet pile 10a has a substantially trapezoidal shape, and its length in the width direction gradually increases toward the flange portions 12a, 12a. Therefore, the cross-sectional shape of the gap 21 between the sheet piles 10b, 10b in the horizontal direction also has a substantially trapezoidal shape. Since the formwork panel 30 is adjacent to the underground structural side surface of the flange portion 12a of the sheet pile 10a and is assembled between the sheet piles 10b, 10b, the cross-sectional shape of the formwork panel in the width direction is a substantially trapezoidal shape corresponding to the gap 21. When the distance between sheet piles 10b and 10b on the extended plane of the underground structural side surface of the flange portion 12a of sheet pile 10a is L11, the distance between the protruding portions 11b and 11b of sheet piles 10b and 10b on the extended plane of the underground structural side surface of the protruding portion 11b of sheet pile 10b is L12, the distance from the underground structural side surface of the flange portion 12a of sheet pile 10a to the underground structural side surface of the protruding portion 11b of sheet pile 10b is D11, the width direction length of the surface of the formwork panel 30 on the side opposite to the underground structure is L21, the width direction length of the surface of the formwork panel on the underground structural side is L22, and the distance from the surface of the formwork panel 30 on the side opposite to the underground structure to the surface of the formwork panel on the underground structural side is D21, the following relationship is preferably satisfied.
[0035] L11 = L21 L12 = L22 D11 = D21 The above relationships may include a certain amount of error, and as long as the elasticity of the synthetic resin foam is sufficient to allow the template panel 30 to be assembled between sheet piles 10b and 10b, the lengths L21 and L22 of the template panel 30 may be slightly greater than L11 and L12.
[0036] The formwork panel 30 is a component used to prevent concrete from penetrating into the recessed portion (14, 21) of the retaining wall 20. However, since the thickness of the concrete wall 40 is determined from the side closer to the underground structure of the surface of the formwork panel 30 on the underground structure side and the surface of the protrusion 11b of the sheet pile 10b on the underground structure side, in order to minimize the amount of concrete poured, it is desirable that the error between D11 and D21 be small, so that the surface of the formwork panel 30 on the underground structure side and the surface of the protrusion 11b of the sheet pile 10b on the underground structure side form a continuous surface.
[0037] Furthermore, if the underground wall 50 is to have a thermal insulation function, the thermal insulation layer can be easily constructed by adding the required thickness of the thermal insulation layer to D11 to obtain D21, and by setting an thermal insulation panel including the same or different synthetic resin foam as the template panel 30 on the underground structure side of the protrusion 11b of the sheet pile 10b. Figure 7 This is a schematic cross-sectional view in the horizontal direction of a construction example of an underground wall 50 with such insulation. Figure 7 In the figure, reference numeral 70 indicates an insulation panel, which is continuous with the template panel 30 and forms an insulation layer.
[0038] Figure 8 This demonstrates an application example of the shape of template panel 30. Figure 8 This is a schematic cross-sectional view of the template panel 30 in the width direction. Preferably, the template panel 30 is not easily detached from the sheet piles 10b after assembly, and from this perspective, it is preferable to have a protrusion on the side surface (side surface of the protrusion 11b) that contacts the side surface of the sheet pile 10b. Figure 8 In (a) and (b), the recess and protrusion 31 are provided on the side surface. By making the width length of the protrusion greater than or equal to the horizontal length of the corresponding gap 21, the protrusion is squeezed by the elastic force of the synthetic resin foam during assembly, and after assembly, the residual stress in the squeezed portion causes the side surface to press against the side surface of the sheet pile 10b, thereby making it less likely for the template panel 30 to detach from the sheet piles 10b. It should be noted that if the width length of the protrusion is too large compared to the horizontal length of the corresponding gap 21, it is difficult to assemble the template panel 30, and there is a possibility that a gap may be formed between the side surface other than the protrusion and the side surface of the sheet pile 10b after assembly. Therefore, it is preferable that the length of the template panel 30 at the protrusion is about 5 mm to 10 mm larger than the horizontal length of the corresponding gap 21.
[0039] Furthermore, from the viewpoint of making it easier to assemble the formwork panel 30 between the sheet piles 10b, 10b of the retaining wall 20, the slit 32 can be set on the underground structural side of the formwork panel 30, such as... Figure 8 (c) As shown. Further, as... Figure 8 As shown in (d) and (e), by providing a recessed portion 33 on one side of the formwork panel 30 opposite to the underground structure, the two ends of the formwork panel 30 on the opposite side of the underground structure in the width direction can be more easily flexed inward, thereby making it easier to assemble between the sheet piles 10b, 10b. It is also possible to... Figure 8 The shapes shown in (a) and (b) are similar to Figure 8 The shape combinations shown in (c) to (e).
[0040] Furthermore, such as Figure 9 As shown, the template panel 30 may have a support section 34 on the side opposite to the underground structure. Figure 9 It is a schematic cross-sectional view of the template panel 30 in the width direction, and Figure 9The diagram shows the formwork panel 30 assembled between the sheet piles 10b, 10b of the retaining wall 20. The support portion 34 can be attached to the formwork panel 30 described above using adhesives or the like, or it can be integrally molded. Furthermore, Figure 10 This is a schematic cross-sectional view of the central portion of the template panel 30 in the width direction, including the support column portion 34, in the vertical direction, wherein the support column portion 34 can be arranged vertically along the entire template panel 30 (e.g., Figure 10 (a) As shown), it can be partially set (such as Figure 10 (b) shown), or a recess 34a may be provided in the central portion (as shown in the figure). Figure 10 (c) as shown). Furthermore... Figure 8 The shape in can be with Figure 9 and Figure 10 Combinations of shapes from (a) to (c). Furthermore, it can also take the form where the side opposite to the underground structure is flat in both the upper and lower portions (e.g., Figure 6 As shown), and has a recessed portion 33 in the area separated from both the upper and lower portions (as shown). Figure 10 (d) and (e) are shown. Figure 8 (d) and (e) correspond to Figure 10 (d) and (e) are schematic cross-sectional views of the central portion in the vertical direction in the width direction.
[0041] If the vertical length of the template panel 30 of the present invention is insufficient for the vertical length of the retaining wall 20, then multiple template panels 30 can be arranged vertically and connected to each other. Figure 11 It shows the form of the link. Figure 11 This is a schematic cross-sectional view of the central portion of the template panel 30 in the width direction in the vertical direction, and... Figure 11 In (a), two template panels 30, 30 are stacked vertically, with sealing tape 35 applied to the joint. Figure 11 (b) illustrates a connection method known as a spline joint, wherein grooves 36, 36 are formed in the lower surface of the upper template panel 30 and the upper surface of the lower template panel 30, and separately prepared splines 37 are fitted into the grooves 36, 36 to connect the panels. The splines 37 may be made of the same material as the template panel 30 or of a different material (e.g., wood or steel), and since the template panel 30 of the present invention is a synthetic resin foam, a non-foamed material of the same synthetic resin may also be used.
[0042] Figure 11 (c) is a connection method known as overlapping, wherein corresponding steps are formed in the contacting surfaces of the upper and lower template panels 30. Further, as... Figure 11As shown in (d), the connection can be achieved by providing a recessed portion 38 on one side and a protruding portion 39 on the other side, and Figure 11 (d) shows an example where the side surfaces of the recessed portion 38 and the protruding portion 39 are tapered. Figure 11 In the constructions from (b) to (d), it can be related to Figure 11 The same sealing tape 35 as in (a) is applied to the joint.
[0043] The template panel 30 of the present invention comprises at least synthetic resin foam, and preferably only synthetic resin foam. Polystyrene foam, polyurethane foam, polyphenol foam, and polyester foam are used as resin materials, and polyethylene terephthalate foam is preferred as a polyester foam. Polystyrene foam is preferred, and extruded foam molding products or beaded foam molding products can be used, with extruded foam molding products being preferred. Further, to adjust the strength, as described below, a non-foamed synthetic resin film can be attached to the surface of the synthetic resin foam, and in this case, the non-foamed synthetic resin film is attached at least to the surface on the sheet pile 10a side, but it can also be attached to both the sheet pile 10a side and the underground structure side. Further, as the synthetic resin film, a polyester film (e.g., polyethylene terephthalate film), a polyolefin film (e.g., polyethylene film and polypropylene film), or a film laminated with polystyrene, polyvinyl acetate, copolymers of polyethylene and polyvinyl acetate, linear low-density polyethylene, etc., is preferably used as an adhesive layer for thermally laminating the film to the synthetic resin foam.
[0044] Furthermore, the template panel 30 of the present invention should have strength capable of withstanding concrete pressure, and preferably has a strength per 1 cm length (perpendicular to) Figure 6 (Page orientation) 20,000 N·cm 2 (0.002 kPa·m) 4 And more preferably at least 30,000 N·cm 2 (0.003 kPa·m) 4 The bending stiffness of the template panel 30 is further increased by increasing the density of the synthetic resin foam. However, the bending stiffness of the template panel 30 exceeds 10,000,000 N·cm. 2 (1 kPa·m) 4 The high-density synthetic resin foam not only increases the weight when processed into template panels, but also reduces dimensional accuracy. Therefore, the bending stiffness of the template panel 30 is preferably at most 10,000,000 N·cm. 2 (1 kPa·m) 4 ), and more preferably at most equal to 5,000,000 N·cm 2(0.5 kPa·m) 4 ).
[0045] The formwork panel 30 will vary depending on the size of the sheet piles to be used, but the preferred size for sheet piles to be used with the formwork panel of the present invention for one sheet pile in the retaining wall 20 is a width of 400 mm and a height of approximately 100 mm to 170 mm (in Figure 6 (in the direction indicated by arrow C). Therefore, the size of the template panel 30 of the present invention is a width L22 that is just below 500 mm (shown in...). Figure 6 The thickness of D21 ranges from 75 mm to 140 mm and the length is approximately 2,000 mm.
[0046] The bending stiffness per 1 cm length of the template panel 30 is obtained by: cutting a suitable length from the template panel 30 to prepare a test specimen; measuring the apparent flexural modulus E (kPa) of the test specimen by means of testing; and calculating the bending stiffness using the following formula based on the apparent flexural modulus E and dimensions of the test specimen used in the measurement. It should be noted that in the JIS K7221-2 test, the “width” of the test specimen is the “length” of the test specimen cut from the template panel 30 of the present invention, and in the test, Figure 6 The shorter side (length: L21) of the trapezoid of the template panel 30 shown is placed on the fulcrum B side, and the longer side (length: L22) is placed on the pressure wedge A side. Therefore, in the JIS K 7221-2 test, the "thickness" of the test piece is the "thickness" of the test piece cut from the template panel 30 of the present invention, that is, the thickness of the template panel 30. Figure 6 (D21 in the middle).
[0047] Bending stiffness per 1 cm length = apparent flexural modulus E × section moment I / b The second moment of the cross section I = bd 3 / 12 b: Length of the test piece ( Figure 6 L21 in d: Thickness of the template panel (30) Figure 6 D21 in It should be noted that if the template panel 30 consists only of synthetic resin foam, a thin test piece can be cut to measure E as described above. However, if the template panel 30 includes synthetic resin foam (with a synthetic resin film attached to its surface), the thickness of the test piece should remain the same as the thickness of the template panel 30. Furthermore, if the thickness of the template panel 30 varies depending on the location, such as... Figure 8 (d), (e) and Figure 10As shown, the thickness of the template panel 30 is considered to be the thickness of the thinnest part, and E described above is measured by cutting test pieces with uniform thickness, such that the thickness of each test piece corresponds to the thickness at the corresponding position.
[0048] If the flexural stiffness of synthetic resin foam is 20,000 N·cm per 1 cm length 2 If the flexural stiffness of the synthetic resin foam is greater than or equal to 20,000 N·cm, then the synthetic resin foam can be used alone as template panel 30, and if the flexural stiffness of the synthetic resin foam is less than 20,000 N·cm... 2 In this case, it is preferable to attach the synthetic resin film to the synthetic resin foam as described above to increase the bending stiffness of the template panel 30.
[0049] Furthermore, if the template panel 30 of the present invention is too rigid, it will be difficult to assemble it between the sheet piles 10b, 10b, and therefore, the side surface direction of the template panel (the direction in which it receives compressive force when assembled between the sheet piles, i.e., according to JIS K 7220) is also important. Figure 6 The compressive strength in the direction indicated by arrow B is preferably less than 20 N / cm. 2 (200 kPa), and more preferably less than 16 N / cm 2 (160 kPa). Furthermore, if the compressive strength of the template panel 30 is less than 5 N / cm... 2 If the compressive strength is less than 50 kPa, the template panel will not be able to withstand changes in gas pressure within the bubble caused by temperature fluctuations or forces applied by hands or fingertips during transport or construction, and will be prone to deformation. Therefore, the compressive strength of the template panel 30 is preferably at least 5 N / cm. 2 (50 kPa), and more preferably at least equal to 9 N / cm 2 (90 kPa). The template panel of the present invention preferably has a combination of shape, size, bending stiffness and compressive strength referred to above as a preferred embodiment.
[0050] [List of Labels in the Attached Images] 10, 10a, 10b: Sheet piles; 11, 11a, 11b: Protruding parts; 12, 12a, 12b: Flange parts; 13, 13a, 13b: Joint parts; 14: Recessed parts; 20: Retaining wall; 21: Gap; 30: Formwork panel; 32: Recesses and protrusions; 33: Recessed parts; 34: Support parts; 34a: Recessed parts; 35: Sealing tape; 36: Groove; 37: Spline; 38: Recessed parts; 39: Recessed parts; 40: Concrete wall; 50: Underground wall; 61: External formwork; 62: Horizontal brace; 63: Support; 64: Internal formwork; 70: Insulation layer.
Claims
1. An underground wall surrounding an underground structure, the underground wall comprising: A retaining wall is formed by joining a plurality of sheet piles, each having a protruding portion, together at their end portions in the width direction, and by penetrating the sheet piles into the soil such that the protruding portions alternately face opposite directions in the horizontal direction. A synthetic resin foam body is assembled between two sheet piles having a protrusion facing the underground structure side, and the opening of the sheet pile having a protrusion facing the side opposite to the underground structure side is closed. as well as A concrete wall arranged to contact the sheet piles having the projecting portion facing the side of the underground structure.
2. A method for constructing an underground wall as described in claim 1, the method comprising: The steps for forming a retaining wall are as follows: multiple sheet piles, each having a protruding portion, are joined together at their end portions in the width direction, and the sheet piles are penetrated into the soil such that the protruding portions alternately face opposite directions in the horizontal direction. The step of excavating the soil between the retaining wall and the underground structure. The step of assembling a formwork panel between two sheet piles having a protrusion facing the underground structure side to close the opening of the sheet pile having a protrusion facing the side opposite to the underground structure side. The steps for setting the internal template at a predetermined distance on the underground structural side of the retaining wall, and The step of pouring concrete between the retaining wall and the internal formwork. The template panel includes at least synthetic resin foam.
3. A template panel for use in an underground wall as described in claim 1, wherein, In a retaining wall formed by joining multiple sheet piles, each having a protruding portion, to each other at their width-direction end portions such that the protruding portions alternately face opposite directions in the horizontal direction, the formwork panel has a cross-sectional shape that can be fitted between two sheet piles having protruding portions facing the underground structure side, and includes at least synthetic resin foam.
4. The template panel as described in claim 3, wherein, The bending stiffness of the template panel is at least 20,000 N·cm per 1 cm length. 2 And at most equal to 10,000,000 N·cm 2 .
5. The template panel as described in claim 3, wherein, The compressive strength of the template panel in the direction of its side surface is at least 5 N / cm. 2 And less than 20 N / cm 2 .
6. The template panel as described in claim 3, wherein, The synthetic resin foam is a polystyrene extruded foam molded product.
7. The template panel as described in any one of claims 3 to 6, wherein, The synthetic resin foam has a protruding portion on the side surface that contacts the sheet pile.