WO2021023245A1 - 桩板式挡土墙整体浇筑模板结构及其施工方法 - Google Patents

桩板式挡土墙整体浇筑模板结构及其施工方法 Download PDF

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Publication number
WO2021023245A1
WO2021023245A1 PCT/CN2020/107263 CN2020107263W WO2021023245A1 WO 2021023245 A1 WO2021023245 A1 WO 2021023245A1 CN 2020107263 W CN2020107263 W CN 2020107263W WO 2021023245 A1 WO2021023245 A1 WO 2021023245A1
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Prior art keywords
mold
retaining wall
pile
slab
formwork structure
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PCT/CN2020/107263
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English (en)
French (fr)
Inventor
张学杰
祁克军
楚士川
张睿智
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上海建工二建集团有限公司
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Publication of WO2021023245A1 publication Critical patent/WO2021023245A1/zh

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    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D15/00Handling building or like materials for hydraulic engineering or foundations
    • E02D15/02Handling of bulk concrete specially for foundation or hydraulic engineering purposes
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00Independent underground or underwater structures; Retaining walls
    • E02D29/02Retaining or protecting walls
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00Independent underground or underwater structures; Retaining walls
    • E02D29/02Retaining or protecting walls
    • E02D29/0258Retaining or protecting walls characterised by constructional features
    • E02D29/0275Retaining or protecting walls characterised by constructional features cast in situ

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  • the invention relates to the technical field of pouring pile-slab retaining walls, in particular to a pile-slab retaining wall integral pouring formwork structure and a construction method thereof.
  • the existing pile-slab retaining wall mainly adopts the combination of cast-in-place method and prefabricated assembly, including: (1) partial pouring of the pile body underground, partial pouring of the pile body above the ground, prefabricated installation of the retaining wall between the piles or support form pouring.
  • (1) The underground part of the pile body is poured, the upper part of the pile body is poured, and the retaining wall between the piles is prefabricated.
  • the construction process positioning, foundation treatment ⁇ excavation of the underground part of the pile body ⁇ pouring and inspection of the underground part of the pile body ⁇ scaffolding ⁇ pile Formwork pouring of part of the body above the ground ⁇ prefabricated installation of retaining wall between piles or formwork pouring ⁇ maintenance.
  • the existing construction method of pile-slab retaining wall has low construction cost, but has the disadvantages of complicated procedures, many construction joints, and long construction period.
  • the purpose of the present invention is to provide a pile-slab retaining wall integral pouring formwork structure and its construction method, which can shorten the construction period, improve the structural integrity, and solve the low construction cost of the existing pile-slab retaining wall construction method and the disadvantages It is the problem of complicated procedures, many construction joints and long construction period.
  • the present invention provides the following technical solutions:
  • the invention discloses a pile plate type retaining wall integral pouring formwork structure, which is used for integral pouring of the retaining wall between the above-ground part of the pile body and the pile body. It includes an inner mold and an outer mold and two baffle molds. The ends of the mold and the outer mold are respectively closed by a baffle mold, the inner mold is a large flat mold for the back wall, and the inner mold includes an outer chamfer mold, an inner pier mold, an inner chamfer mold, and an inner wedge mold, The two ends of the large flat mold for the back wall are respectively provided with the baffle mold, and the end of the baffle mold away from the large flat mold of the back wall is provided with the outer chamfering mold.
  • An inner pier mold is set at the end far away from the baffle mold, and an inner chamfer mold is set on the end far away from the outer chamfer mold on the inner pier mold.
  • the adjacent inner chamfer molds are connected by an inner wedge mold, and the inner side is inverted.
  • the corner mold is L-shaped, the corner of the inner chamfering mold and the large flat mold of the back wall are fixed by tie rods, the outer chamfering mold is L-shaped, and the corner of the outer chamfering mold is connected to the back wall
  • the large flat molds are fixed by tie rods, and the end of the large flat mold of the back wall and the end of the outer chamfering mold are fixed by tie rods.
  • the distance between the tie rods along the height direction of the retaining wall is 700-900 mm.
  • the inner pier mold and the inner chamfering mold, and the inner pier mold and the outer chamfering mold are fixed by diagonal tie rods.
  • the inner chamfering mold and the inner wedge-shaped mold are fixed by oblique supports.
  • the large back wall flat mold, baffle mold, outer chamfering mold, inner pier mold, inner chamfering mold, and inner wedge mold all include panels , Vertical ribs, horizontal ribs and a back bar structure, wherein the vertical ribs and horizontal ribs are arranged criss-crossedly on the back of the panel to form a mesh structure, and the back bar structure is arranged on the outside of the mesh structure.
  • the back bar structure includes two horizontal channel steels and a plurality of connecting channels, and the two horizontal channel steels are connected by the connecting channels,
  • the connecting channel steels are arranged at equal intervals along the horizontal direction, and the two horizontal channel steels are arranged opposite to each other.
  • the retaining wall between the above-ground part of the pile body and the pile body is made of C40 high-performance concrete, and the section length of the retaining wall is 16m.
  • a vertical expansion joint is set in each section, and the joint width is 20-30mm.
  • the back bar structure includes two horizontal channel steels and a plurality of connecting channels, and the two horizontal channel steels are connected by the connecting channels,
  • the connecting channel steels are arranged at equal intervals along the horizontal direction, and the two horizontal channel steels are arranged opposite to each other.
  • horizontal flanges are respectively provided on both vertical sides of the panel, vertical flanges are respectively provided on both lateral sides of the panel, and the back bar structure Back bar flanges are respectively provided on both sides of the transverse direction.
  • the retaining wall is divided into several sections horizontally, and a vertical expansion joint is arranged between adjacent sections, and the joint width is 20-30 mm.
  • the integral pouring formwork structure of said pile-slab retaining wall is divided into several sections from bottom to top, and adjacent sections are connected by vertical flanges and back-bar flanges.
  • the invention also discloses a construction method for the integral pouring structure of the pile-slab retaining wall, which includes the following steps:
  • Step one positioning and foundation treatment
  • Step 2 Excavation of the underground part of the pile
  • Step 3 pouring and testing the underground part of the pile
  • Step four erect scaffolding
  • Step 5 Binding the part of the steel bars above the ground of the pile body and the retaining wall between the piles;
  • Step 6 supporting form pouring, using the above-mentioned pile-slab retaining wall integral pouring formwork structure, the formwork structure adopts a steel formwork, and the formwork structure is divided into several sections from bottom to top. After the assembly is completed on the ground, it is hoisted by crane In place
  • Step seven remove the mold and maintain it.
  • the integral pouring formwork structure of the pile-slab retaining wall adopts a large back wall flat mold, a baffle mold, an outer chamfering mold, an inner pier body mold, an inner chamfering mold, and an inner wedge mold.
  • the two ends of the large flat mold are respectively provided with baffle molds, the end of the baffle mold away from the large flat mold of the back wall is provided with the outer chamfering mold, and the end of the outer chamfering mold is provided at the end far from the baffle mold
  • the integral pouring formwork of the retaining wall of the retaining wall, through the setting of tie rods to achieve a stable connection between the inner and outer forms, which can resist the lateral pressure of the newly poured concrete, and the horizontal force on the formwork structure when the concrete is poured and vibrated.
  • the integral pouring of the retaining wall between the part and the pile body can shorten the construction period, improve the structural integrity, and solve the problem of the low construction cost of the existing pile-slab retaining wall construction method.
  • the disadvantage is that the process is complicated and the construction joints are many. , The problem of long construction period.
  • the construction method for integral pouring of pile-slab retaining wall provided by the present invention, after pouring the underground part of the pile body and passing the test; erecting scaffolding, the scaffolding adopts a disc-buckle type scaffolding system; ; Formwork pouring adopts the above-mentioned pile-slab retaining wall integral pouring formwork structure, the formwork structure is divided into several sections from bottom to top, after the completion of the assembly on the ground, the crane is used to hoist in place, and finally the mold is removed for maintenance.
  • Pile-slab retaining wall pile body and retaining wall structure concrete high-supported formwork one-time integral pouring technology, no need for layered pouring, no need to pour the pile body first, and then construct the retaining wall, which greatly simplifies the pile-slab retaining wall
  • the construction technology of the structure above the wall and the ground Since the pile body and retaining wall are cast integrally, there are no construction joints, the controllability of construction quality is stronger, and the process is simplified. Since the pile body and the retaining wall are integrally poured, the number of concrete maintenance is reduced, thereby effectively saving the construction period.
  • Fig. 1 is a schematic structural diagram of an integrally poured formwork structure of a pile-slab retaining wall according to an embodiment of the present invention before pouring;
  • Figure 2 is a schematic structural diagram of the integral pouring formwork structure of the pile-slab retaining wall according to an embodiment of the present invention after pouring;
  • FIG. 3 is a schematic diagram of the integral pouring structure of the retaining wall between the above-ground part of the pile body and the pile body in an embodiment of the present invention
  • FIG. 4 is a schematic diagram of the structure of the inner pier mold in an embodiment of the present invention.
  • Figure 5 is a side view of Figure 4.
  • Figure 6 is a top view of Figure 4.
  • Figure 7 is a schematic diagram of the horizontal section of the integral pouring formwork structure of the pile-slab retaining wall.
  • the present invention discloses a pile-slab retaining wall integral pouring formwork structure, used for the integral pouring of the retaining wall 200 between the above-ground part of the pile body 100 and the pile body 100, including an inner mold and The outer mold and the two baffle molds 1, the ends of the inner mold and the outer mold are respectively closed by the baffle mold 1, the inner mold includes the outer chamfering mold 2, the inner pier mold 3, the inner chamfering mold 4 and The inner wedge mold 5, the inner mold is a large flat mold 6 for the back wall, the baffle mold 1 is set at both ends of the large flat mold 6 for the back wall, and the baffle mold 1 is far away from the large back wall.
  • One end of the flat block mold 6 is provided with the outer chamfering mold 2, and the end of the outer chamfering mold 2 away from the baffle mold 1 is provided with an inner pier mold 3, and the inner pier mold 3 is far away from the outer chamfering
  • One end of the mold 2 is provided with an inner chamfering mold 4, and adjacent inner chamfering molds 4 are connected by an inner wedge mold 5.
  • the inner chamfering mold 4 is L-shaped, and the corners of the inner chamfering mold 4 are connected to the back
  • the large wall flat molds 6 are fixed by tie rods 7.
  • the outer chamfering mold 2 is L-shaped, and the corners of the outer chamfering mold 2 and the back wall bulk flat mold 6 are fixed by tie rods 7, so The end of the large flat mold 6 for the back wall and the end of the outer chamfering mold 2 are fixed by tie rods 7.
  • the integral pouring formwork structure of the pile-slab retaining wall provided by the present invention adopts a large back wall flat mold 6, a baffle mold 1, an outer chamfer mold 2, an inner pier mold 3, an inner chamfer mold 4, and an inner wedge mold. 5. Both ends of the large flat mold 6 for the back wall are respectively provided with baffle molds 1, and the end of the baffle mold 1 far away from the large flat mold 6 for the back wall is provided with the outer chamfering mold 2.
  • the end of the chamfering mold 2 away from the baffle mold 1 is provided with an inner pier mold 3, and the end of the inner pier mold 3 far from the outer chamfering mold 2 is provided with an inner chamfering mold 4, one of the adjacent inner chamfering molds 4 They are connected by the inner wedge-shaped mold 5, thus forming the integral pouring formwork of the retaining wall 200 between the above-ground part of the pile body 100 and the pile body 100.
  • the tie rods 7 are provided to achieve a stable connection between the inner and outer molds, which can resist new The lateral pressure of pouring concrete, the horizontal force on the formwork structure when pouring and vibrating the concrete, realize the integral pouring of the retaining wall 200 between the above-ground part of the pile 100 and the pile 100, thereby shortening the construction period and improving the structural integrity Yes, it solves the problems of low construction cost of the existing pile-slab retaining wall 200 construction method, but the disadvantages are complicated procedures, many construction joints, and long construction period.
  • the cross-sectional size of the pile body 100 is 2100*2000mm
  • the wall thickness of the retaining wall is 400mm
  • the center distance of the pile body 100 is 2000mm.
  • the distance between the tie rods along the height direction of the retaining wall 200 is 700-900mm, so as to improve the stability between the inner mold and the outer mold, which is beneficial to resist the lateral pressure of the newly poured concrete, and the impact on the formwork structure when the concrete is poured and vibrated.
  • the horizontal force realizes the integral pouring of the retaining wall 200 between the above ground part of the pile body 100 and the pile body 100.
  • the inner wedge mold 5 includes a panel 10, a vertical rib 11, a horizontal rib 12, and a back bar structure.
  • the vertical ribs 11 and the horizontal ribs 12 are arranged criss-crossed on the back of the panel 10 to form a mesh structure, and the back bar structure is arranged at The outside of the mesh structure.
  • the maximum distance between the horizontal ribs 12 is 300 mm
  • the maximum distance between the vertical ribs 11 is also 300 mm.
  • the upper and lower sides of the panel 10, that is, the vertical sides are respectively provided with horizontal flanges 12 for vertical butting
  • the left and right sides of the panel 10, that is, the horizontal sides are respectively provided with vertical flanges for realizing the left and right lateral butting.
  • the left and right sides of the back bar structure, that is, the lateral sides are respectively provided with back bar flanges 18 for realizing left and right lateral butt joints.
  • the inner pier mold 3 and the inner chamfering mold 4, and the inner pier mold 3 and the outer chamfering mold 2 pass through diagonal tie rods. 8Fixed to improve the strength of the outer corners of the outer mold, increase the overall strength of the formwork structure, and improve construction safety.
  • the inner chamfering mold 4 and the inner wedge-shaped mold 5 are fixed by oblique supports 9 so as to increase the strength of the inner corners of the outer mold and increase the formwork The overall strength of the structure.
  • the panel 10 uses 6mm thick steel plate
  • the vertical ribs 11 and the horizontal ribs 12 use 10# or 20# channel steel
  • the vertical flange 13, the horizontal flange 12, and the back bar flange 18 have a thickness of 12mm.
  • 7 and 8 use M30 ordinary rebar.
  • the back bar structure includes two horizontal channel steels 15 and a plurality of connecting channel steels 16, and the two horizontal channel steels 15 pass through the connection
  • the channel steels 16 are connected, the connecting channel steels 16 are arranged at equal intervals along the horizontal direction, and the two horizontal channel steels 15 are arranged opposite to each other.
  • the retaining wall is divided into several sections horizontally, and a vertical expansion joint 19 is arranged between adjacent sections, with a joint width of 20-30 mm.
  • the middle is divided into three sections ABC, and the length of each section of the retaining wall 200 is 16 m.
  • the integral pouring formwork structure of the pile-slab retaining wall is divided into several sections from bottom to top, and adjacent sections are connected by vertical flanges 13 and back bar flanges 18, which can be combined or divided into sections.
  • the retaining wall 200 between the above-ground part of the pile body 100 and the pile body 100 is made of C40 high-performance concrete, with an impermeability grade of P8, and The freezing level is F300.
  • the present invention also discloses a construction method for integral pouring of a pile-slab retaining wall, which includes the following steps:
  • Step one positioning and foundation treatment
  • Step 2 Excavation of the underground part of the pile 100
  • Step 3 pouring and testing the underground part of pile 100;
  • Step four erect scaffolding, the scaffolding adopts a disc-buckle scaffolding system
  • Step 5 the part of the steel bars above the ground of the pile body 100 and the retaining wall 200 between the piles are bound; when the steel bars are bound, a cushion is set on the outside of the steel bars and fastened with steel wires. In this way, the thickness of the concrete protective layer is controlled.
  • Step six support form pouring, using the pile-slab retaining wall as described in the first implementation of the integral pouring formwork structure, the formwork structure adopts a steel formwork, the formwork structure is divided into several sections from bottom to top, after the completion of assembly on the ground, use The crane is hoisted in place.
  • Step seven remove the mold and maintain it.
  • the construction method for integrally pouring the pile-slab retaining wall provided by the present invention is constructed after the underground part of the pile body 100 is poured and passed the test; scaffolding is erected, and the scaffolding adopts a disc-buckle scaffold system; the pile body 100 and the retaining wall between the piles 200 are above the ground Part of the steel bars are bound; the pile-slab retaining wall as described above is used for the integral pouring formwork structure in the formwork pouring.
  • the formwork structure is divided into several sections from bottom to top. After the ground is assembled, it is hoisted in place by a crane, and finally the mold is removed for maintenance.
  • the pile body 100 and the retaining wall 200 structure concrete high support formwork, there is no need for layered pouring, no need to pour the pile body 100 first, and then construct the retaining wall 200.
  • the construction process of the structure above the ground of the pile-slab retaining wall 200 is simplified. Since the pile body 100 and the retaining wall 200 are integrally poured, there is no construction joint between the pile body 100 and the retaining wall 200, the controllability of the construction quality is stronger, and the process is simplified. In addition, since the pile body 100 and the retaining wall 200 are cast integrally, the number of concrete curing is reduced, thereby effectively saving the construction period.

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Abstract

本发明的桩板式挡土墙整体浇筑模板结构及其施工方法,涉及桩板式挡土墙浇筑技术领域。针对现有的桩板式挡土墙的施工方法的施工工序繁琐,施工缝多,施工周期长的问题。本发明包括内侧模与外侧模以及两挡板模,所述内侧模与外侧模的端部分别通过挡板模封闭,所述内侧模为背墙大块平模,所述内侧模包括外侧倒角模、内侧墩身模、内侧倒角模以及内侧楔形模,从而在桩板式挡土墙桩身及挡土墙结构混凝土高支模一次性整体浇筑技术施工时,无需分层浇筑,无需先浇筑桩身的地上部分,再施工挡土墙,极大的简化了桩板式挡土墙地面以上结构的施工工艺,免去了桩身的地上部分与挡土墙之间的施工缝,工序更加简化,施工质量的可控性更强,并可有效节约工期。

Description

桩板式挡土墙整体浇筑模板结构及其施工方法 技术领域
本发明涉及桩板式挡土墙浇筑技术领域,尤其涉及一种桩板式挡土墙整体浇筑模板结构及其施工方法。
背景技术
现有的桩板式挡土墙的施工主要采用现浇法及预制拼装结合,包括:(1)桩身地下部分浇筑,桩身地上部分浇筑,桩间挡土墙预制安装或支模浇筑。(1)桩身地下部分浇筑,桩身地上部分浇筑,桩间挡土墙预制安装施工工艺流程:定位、地基处理→桩身地下部分开挖→桩身地下部分浇筑、检测→脚手架搭设→桩身地面以上部分支模浇筑→桩间挡土墙预制安装或支模浇筑→养护。
现有的桩板式挡土墙的施工方法具有施工成本较低,缺点是工序繁琐,施工缝多,施工周期长。
如何提供一种能够缩短工期,提高了结构整体性的桩板式挡土墙整体浇筑模板结构及其施工方法,已成为建筑施工界需进一步完善优化的技术问题。
发明内容
本发明的目的在于提供一种桩板式挡土墙整体浇筑模板结构及其施工方法,能够缩短工期,提高了结构整体性的,解决现有的桩板式挡土墙施工方法施工成本较低,缺点是工序繁琐,施工缝多,施工周期长的问题。
为解决上述技术问题,本发明提供如下技术方案:
本发明公开了一种桩板式挡土墙整体浇筑模板结构,用于桩身地上部分与桩身之间的挡土墙的整体浇筑,包括内侧模与外侧模以及两挡板模,所述内侧模与外侧模的端部分别通过挡板模封闭,所述内侧模为背墙大块平模,所述内侧模包括外侧倒角模、内侧墩身模、内侧倒角模以及内侧楔形模,所述背墙大 块平模的两端分别设置所述挡板模,所述挡板模上远离背墙大块平模的一端设置所述外侧倒角模,所述外侧倒角模上的远离挡板模的一端设置内侧墩身模,所述内侧墩身模上远离外侧倒角模的一端设置内侧倒角模,相邻内侧倒角模之间通过内侧楔形模连接,所述内侧倒角模呈L型,所述内侧倒角模的转角处与背墙大块平模之间通过拉杆固定,所述外侧倒角模呈L型,所述外侧倒角模的转角处与背墙大块平模之间通过拉杆固定,所述背墙大块平模的端部与外侧倒角模的端部通过拉杆固定。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述拉杆沿着挡土墙高度方向的间距为700-900mm。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述内侧墩身模与内侧倒角模以及所述内侧墩身模与外侧倒角模之间均通过斜拉杆固定。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述内侧倒角模与内侧楔形模之间通过斜支撑固定。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述背墙大块平模、挡板模、外侧倒角模、内侧墩身模、内侧倒角模以及内侧楔形模均包括面板、竖筋、横筋以及背杠结构,所述竖筋、横筋纵横交错设置于所述面板的背面形成网状结构,所述背杠结构设置于所述网状结构的外侧。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述背杠结构包括两根水平槽钢以及若干连接槽钢,所述两根水平槽钢之间通过所述连接槽钢连接,所述连接槽钢沿着水平方向等间距设置,所述两根水平槽钢相背设置。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述桩身地上部分与桩身之间的挡土墙用C40高性能混凝土,所述挡土墙的分段长度为16m,每分段均设置一道竖向伸缩缝,缝宽20~30mm。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述背杠结构包括两根水平槽钢以及若干连接槽钢,所述两根水平槽钢之间通过所述连接槽钢连接,所述连接槽钢沿着水平方向等间距设置,所述两根水平槽钢相背设置。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述面板的竖向两侧分别设置有横法兰,所述面板的横向两侧分别设置有竖法兰,所述背杠结构的横向两侧分别设有背杠法兰。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述挡土墙横向分成若 干段,相邻段之间设置一道竖向伸缩缝,缝宽20~30mm。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述桩板式挡土墙整体浇筑模板结构由下至上分成若干节,相邻节之间通过竖法兰以及背杠法兰连接。
本发明还公开了一种桩板式挡土墙整体浇筑结构的施工方法,包括如下步骤:
步骤一,定位、地基处理;
步骤二,桩身地下部分开挖;
步骤三,桩身地下部分浇筑、检测;
步骤四,搭设脚手架;
步骤五,桩身及桩间挡土墙地面以上部分钢筋绑扎;
步骤六,支模浇筑,采用如上所述的桩板式挡土墙整体浇筑模板结构,所述模板结构采用钢模板,所述模板结构由下至上分成若干节,在地面完成拼装后,采用吊车吊装就位;
步骤七,拆模养护。
由以上公开的技术方案可知,与现有技术相比,本发明的有益效果如下:
本发明提供的桩板式挡土墙整体浇筑模板结构,通过采用背墙大块平模、挡板模、外侧倒角模、内侧墩身模、内侧倒角模以及内侧楔形模,所述背墙大块平模的两端分别设置挡板模,所述挡板模的远离背墙大块平模的一端设所述外侧倒角模,所述外侧倒角模的远离挡板模的一端设置内侧墩身模,所述内侧墩身模的远离外侧倒角模的一端设置内侧倒角模,相邻内侧倒角模之间通过内侧楔形模连接,如此组成桩身地上部分与桩身之间的挡土墙的整体浇筑模板,通过设置拉杆实现内侧模与外侧模之间的稳固连接,能够抵抗新浇筑混凝土的侧压力、倾倒和振捣混凝土时对模板结构的水平力,实现桩身地上部分与桩身之间的挡土墙的整体浇筑,从而能够缩短工期,提高了结构整体性的,解决现有的桩板式挡土墙施工方法施工成本较低,缺点是工序繁琐,施工缝多,施工周期长的问题。
本发明提供的桩板式挡土墙整体浇筑施工方法,在桩身地下部分浇筑、检测合格后;搭设脚手架,脚手架搭设采用盘扣式脚手架体系;桩身及桩间挡土墙地面以上部分钢筋绑扎;支模浇筑中采用如上所述的桩板式挡土墙整体浇筑 模板结构,所述模板结构由下至上分成若干节,在地面完成拼装后,采用吊车吊装就位,最后拆模养护,从而在桩板式挡土墙桩身及挡土墙结构混凝土高支模一次性整体浇筑技术施工时,无需分层浇筑,无需先浇筑桩身,再施工挡土墙,极大的简化了桩板式挡土墙地面以上结构的施工工艺。由于桩身及挡土墙是整体浇筑的,不存在施工缝,施工质量的可控性更强,工序更加简化。由于桩身及挡土墙是整体浇筑的,减少混凝土养护次数,从而有效节约工期。
附图说明
图1为本发明一实施例的桩板式挡土墙整体浇筑模板结构浇筑前的结构示意图;
图2为本发明一实施例的桩板式挡土墙整体浇筑模板结构浇筑后的结构示意图;
图3为本发明一实施例中桩身地上部分与桩身之间的挡土墙的整体浇筑结构示意图;
图4为本发明一实施例中内侧墩身模的结构示意图;
图5为图4的侧视图;
图6为图4的俯视图;
图7为桩板式挡土墙整体浇筑模板结构横向分段示意图。
图中:100-桩身、200-挡土墙、1-挡板模、2-外侧倒角模、3-内侧墩身模、4-内侧倒角模、5-内侧楔形模、6-背墙大块平模、7-拉杆、8-斜拉杆、9-斜支撑、10-面板、11-竖筋、12-横筋、12-横法兰、13-竖法兰、14-对拉桩、15-水平槽钢、16-连接槽钢、17-加筋槽钢、18-背杠法兰、19-伸缩缝。
具体实施方式
以下结合附图和具体实施例对本发明作进一步详细说明。以下将由所列举之实施例结合附图,详细说明本发明的技术内容及特征。需另外说明的是,附图均采用非常简化的形式且均使用非精准的比例,仅用以方便、明晰地辅助说明本发明实施例的目的。为叙述方便,下文中所述的“上”、“下”与附图的上、下的方向一致,但这不能成为本发明技术方案的限制。
请参阅图1至图7,本发明公开了一种桩板式挡土墙整体浇筑模板结构, 用于桩身100地上部分与桩身100之间的挡土墙200的整体浇筑,包括内侧模与外侧模以及两挡板模1,所述内侧模与外侧模的端部分别通过挡板模1封闭,所述内侧模包括外侧倒角模2、内侧墩身模3、内侧倒角模4以及内侧楔形模5,所述内侧模为背墙大块平模6,所述背墙大块平模6的两端分别设置所述挡板模1,所述挡板模1上远离背墙大块平模6的一端设置所述外侧倒角模2,所述外侧倒角模2上的远离挡板模1的一端设置内侧墩身模3,所述内侧墩身模3上远离外侧倒角模2的一端设置内侧倒角模4,相邻内侧倒角模4之间通过内侧楔形模5连接,所述内侧倒角模4呈L型,所述内侧倒角模4的转角处与背墙大块平模6之间通过拉杆7固定,所述外侧倒角模2呈L型,所述外侧倒角模2的转角处与背墙大块平模6之间通过拉杆7固定,所述背墙大块平模6的端部与外侧倒角模2的端部通过拉杆7固定。
本发明提供的桩板式挡土墙整体浇筑模板结构,通过采用背墙大块平模6、挡板模1、外侧倒角模2、内侧墩身模3、内侧倒角模4以及内侧楔形模5,所述背墙大块平模6的两端分别设置挡板模1,所述挡板模1的远离背墙大块平模6的一端设所述外侧倒角模2,所述外侧倒角模2的远离挡板模1的一端设置内侧墩身模3,所述内侧墩身模3的远离外侧倒角模2的一端设置内侧倒角模4,相邻内侧倒角模4之间通过内侧楔形模5连接,如此组成桩身100地上部分与桩身100之间的挡土墙200的整体浇筑模板,通过设置拉杆7实现内侧模与外侧模之间的稳固连接,能够抵抗新浇筑混凝土的侧压力、倾倒和振捣混凝土时对模板结构的水平力,实现桩身100地上部分与桩身100之间的挡土墙200的整体浇筑,从而能够缩短工期,提高了结构整体性的,解决现有的桩板式挡土墙200施工方法施工成本较低,缺点是工序繁琐,施工缝多,施工周期长的问题。
优选的,在上述的桩板式挡土墙整体浇筑模板结构中,所述桩身100的横截面尺寸为2100*2000mm,挡土墙的墙厚为400mm,桩身100的中心距为2000mm,所述拉杆沿着挡土墙200高度方向的间距为700-900mm,从而提高内侧模与外侧模之间的稳定性,有利于抵抗新浇筑混凝土的侧压力、倾倒和振捣混凝土时对模板结构的水平力,实现桩身100地上部分与桩身100之间的挡土墙200的整体浇筑。
优选的,在上述的桩板式挡土墙整体浇筑模板结构中,所述背墙大块平模 6、挡板模1、外侧倒角模2、内侧墩身模3、内侧倒角模4以及内侧楔形模5均包括面板10、竖筋11、横筋12以及背杠结构,所述竖筋11、横筋12纵横交错设置于所述面板10的背面形成网状结构,所述背杠结构设置于所述网状结构的外侧。通过设置横筋12与纵筋,可以增强模板结构的强度,本实施例中所述横筋12之间的最大间距为300mm,所述竖筋11之间的最大间距也为300mm。此外,所述面板10的上下侧即竖向两侧分别设置有用于实现竖向对接的横法兰12,所述面板10的左右侧即横向两侧分别设置有用于实现左右横向对接竖法兰13,所述背杠结构的左右两侧即横向两侧分别设有用于实现左右横向对接的背杠法兰18。
优选的,在上述的桩板式挡土墙整体浇筑模板结构中,所述内侧墩身模3与内侧倒角模4以及所述内侧墩身模3与外侧倒角模2之间均通过斜拉杆8固定,从而提高外侧模的外侧转角处的强度,增加模板结构的整体强度,提高施工安全性。
优选的,在上述的桩板式挡土墙整体浇筑模板结构中,所述内侧倒角模4与内侧楔形模5之间通过斜支撑9固定,从而提高外侧模的内侧转角处的强度,增加模板结构的整体强度。
本实施中,所述面板10选用6mm厚钢板,竖筋11、横筋12采用10#或20#槽钢,竖法兰13、横法兰12以及背杠法兰18的钢板厚度为12mm,拉杆7与斜拉杆8采用M30普通螺纹钢。
优选的,在上述的桩板式挡土墙整体浇筑模板结构中,所述背杠结构包括两根水平槽钢15以及若干连接槽钢16,所述两根水平槽钢15之间通过所述连接槽钢16连接,所述连接槽钢16沿着水平方向等间距设置,所述两根水平槽钢15相背设置。通过采用如上结构的背杠结构,一方面可以提高桩板式挡土墙整体浇筑模板结构的整体强度,另一方面可以在脚手架与桩板式挡土墙整体浇筑模板结构之间形成有效的斜撑点,提高模板结构的稳定性。
优选的,在上述的桩板式挡土墙整体浇筑结构中,所述挡土墙横向分成若干段,相邻段之间设置一道竖向伸缩缝19,缝宽20~30mm。本实施例中,中分成了ABC三段,所述挡土墙200的每段长度为16m。所述桩板式挡土墙整体浇筑模板结构由下至上分成若干节,相邻节之间通过竖法兰13以及背杠法兰18连接,可组合施工也可分节施工。
优选的,在本实施例的桩板式挡土墙整体浇筑模板结构中,所述桩身100地上部分与桩身100之间的挡土墙200用C40高性能混凝土,抗渗等级为P8,抗冻等级为F300。
请继续参阅图1至图7,本发明还公开一种桩板式挡土墙整体浇筑施工方法,包括如下步骤:
步骤一,定位、地基处理;
步骤二,桩身100地下部分开挖;
步骤三,桩身100地下部分浇筑、检测;
步骤四,搭设脚手架,脚手架搭设采用盘扣式脚手架体系;
步骤五,桩身100及桩间挡土墙200地面以上部分钢筋绑扎;绑扎钢筋时,钢筋外侧设置垫块,并用钢丝扎牢,通过这种方式来控制混凝土保护层厚度。
步骤六,支模浇筑,采用如实施一所述的桩板式挡土墙整体浇筑模板结构,所述模板结构采用钢模板,所述模板结构由下至上分成若干节,在地面完成拼装后,采用吊车吊装就位。
步骤七,拆模养护。
本发明提供的桩板式挡土墙整体浇筑施工方法,在桩身100地下部分浇筑、检测合格后;搭设脚手架,脚手架搭设采用盘扣式脚手架体系;桩身100及桩间挡土墙200地面以上部分钢筋绑扎;支模浇筑中采用如上所述的桩板式挡土墙整体浇筑模板结构,模板结构由下至上分成若干节,在地面完成拼装后,采用吊车吊装就位,最后拆模养护,从而在桩板式挡土墙200桩身100及挡土墙200结构混凝土高支模一次性整体浇筑技术施工时,无需分层浇筑,无需先浇筑桩身100,再施工挡土墙200,极大的简化了桩板式挡土墙200地面以上结构的施工工艺。由于桩身100及挡土墙200是整体浇筑的,桩身100及挡土墙200之间不存在施工缝,施工质量的可控性更强,工序更加简化。此外,由于桩身100及挡土墙200是整体浇筑的,减少混凝土养护次数,从而可有效节约工期。

Claims (10)

  1. 一种桩板式挡土墙整体浇筑模板结构,其特征在于,用于桩身地上部分与桩身之间的挡土墙的整体浇筑,包括内侧模与外侧模以及两挡板模,所述内侧模与外侧模的端部分别通过挡板模封闭,所述内侧模为背墙大块平模,所述内侧模包括外侧倒角模、内侧墩身模、内侧倒角模以及内侧楔形模,所述背墙大块平模的两端分别设置所述挡板模,所述挡板模上远离背墙大块平模的一端设置所述外侧倒角模,所述外侧倒角模上的远离挡板模的一端设置内侧墩身模,所述内侧墩身模上远离外侧倒角模的一端设置内侧倒角模,相邻内侧倒角模之间通过内侧楔形模连接,所述内侧倒角模呈L型,所述内侧倒角模的转角处与背墙大块平模之间通过拉杆固定,所述外侧倒角模呈L型,所述外侧倒角模的转角处与背墙大块平模之间通过拉杆固定,所述背墙大块平模的端部与外侧倒角模的端部通过拉杆固定。
  2. 如权利要求1所述的桩板式挡土墙整体浇筑模板结构,其特征在于,所述拉杆沿着挡土墙高度方向的间距为700-900mm。
  3. 如权利要求1所述的桩板式挡土墙整体浇筑模板结构,其特征在于,所述内侧墩身模与内侧倒角模以及所述内侧墩身模与外侧倒角模之间均通过斜拉杆固定。
  4. 如权利要求1所述的桩板式挡土墙整体浇筑模板结构,其特征在于,所述内侧倒角模与内侧楔形模之间通过斜支撑固定。
  5. 如权利要求1所述的桩板式挡土墙整体浇筑模板结构,其特征在于,所述背墙大块平模、挡板模、外侧倒角模、内侧墩身模、内侧倒角模以及内侧楔形模均包括面板、竖筋、横筋以及背杠结构,所述竖筋、横筋纵横交错设置于所述面板的背面形成网状结构,所述背杠结构设置于所述网状结构的外侧。
  6. 如权利要求5所述的桩板式挡土墙整体浇筑模板结构,其特征在于,所述背杠结构包括两根水平槽钢以及若干连接槽钢,所述两根水平槽钢之间通过所述连接槽钢连接,所述连接槽钢沿着水平方向等间距设置,所述两根水平槽钢相背设置。
  7. 如权利要求5所述的桩板式挡土墙整体浇筑模板结构,其特征在于,所述面板的竖向两侧分别设置有横法兰,所述面板的横向两侧分别设置有竖法 兰,所述背杠结构的横向两侧分别设有背杠法兰。
  8. 如权利要求7所述的桩板式挡土墙整体浇筑模板结构,其特征在于,所述桩板式挡土墙整体浇筑模板结构由下至上分成若干节,相邻节之间通过竖法兰以及背杠法兰连接。
  9. 如权利要求1所述的桩板式挡土墙整体浇筑模板结构,其特征在于,所述挡土墙横向分成若干段,相邻段之间设置一道竖向伸缩缝,缝宽20~30mm。
  10. 一种桩板式挡土墙整体浇筑施工方法,其特征在于,包括如下步骤:
    步骤一,定位、地基处理;
    步骤二,桩身地下部分开挖;
    步骤三,桩身地下部分浇筑、检测;
    步骤四,搭设脚手架;
    步骤五,桩身及桩间挡土墙地面以上部分钢筋绑扎;
    步骤六,支模浇筑,采用如权利要求1-9中任意一项所述的桩板式挡土墙整体浇筑模板结构,所述模板结构采用钢模板,所述模板结构由下至上分成若干节,在地面完成拼装后,采用吊车吊装就位;
    步骤七,拆模养护。
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CN114837172A (zh) * 2022-05-19 2022-08-02 中国建筑第八工程局有限公司 抗滑桩接桩部位与桩间板施工的衔接装置及施工方法
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CN114960306A (zh) * 2022-05-27 2022-08-30 中铁二院成都勘察设计研究院有限责任公司 一种路基支护结构

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CN110409491A (zh) * 2019-08-07 2019-11-05 上海建工二建集团有限公司 桩板式挡土墙整体浇筑模板结构及其施工方法

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2265943A1 (en) * 1974-03-27 1975-10-24 Noirel Christian Formwork for supporting wall - U-shaped units have end panels which swing inwards for extraction after concreting
KR20080001711A (ko) * 2006-06-29 2008-01-04 충주대학교 산학협력단 무지주 공법에 의한 지하 옹벽 시공방법
US20090308011A1 (en) * 2006-07-21 2009-12-17 Phil-Insul Corporation Insulated concrete form panel reinforcement
US8360389B2 (en) * 2007-02-13 2013-01-29 Peri Gmbh Formwork systems for forming corners and T intersections using formwork elements comprising centrally lined up tie holes
CN103498419A (zh) * 2013-10-17 2014-01-08 中铁六局集团有限公司 箱梁钢制芯模及其施工方法
CN203755264U (zh) * 2014-02-25 2014-08-06 宋仲华 一种基于曲线溢流面的闸门墩及其门槽的浇筑成型模具
CN203924692U (zh) * 2014-04-22 2014-11-05 江苏天向新型材料科技有限公司 一种三向t型墙墙体模板
CN207672558U (zh) * 2017-12-14 2018-07-31 中铁二院工程集团有限责任公司 一种铁路路堤钻孔灌注桩桩板墙结构
CN207878928U (zh) * 2017-06-28 2018-09-18 中建三局集团有限公司 一种填充墙砌体构造柱定型钢模
CN108589769A (zh) * 2018-05-07 2018-09-28 安徽省公路桥梁工程有限公司 一种超长嵌岩t形组合式柱板高挡墙施工方法
CN110409491A (zh) * 2019-08-07 2019-11-05 上海建工二建集团有限公司 桩板式挡土墙整体浇筑模板结构及其施工方法
CN210857267U (zh) * 2019-08-07 2020-06-26 上海建工二建集团有限公司 桩板式挡土墙整体浇筑模板结构

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2516358B2 (ja) * 1987-03-17 1996-07-24 岡部株式会社 ア−チコンクリ−ト施工用の型枠支保工
CN201962665U (zh) * 2011-02-23 2011-09-07 陈东曙 一种桩板组合式挡墙
CN203420470U (zh) * 2013-07-05 2014-02-05 天津住宅集团建设工程总承包有限公司 一种短肢剪力墙模板支撑体系的安装施工结构
CN205502571U (zh) * 2016-04-07 2016-08-24 中国建筑第二工程局有限公司 一种墙柱钢模板体系
CN109989576A (zh) * 2019-03-13 2019-07-09 中国建筑第八工程局有限公司 装配整体式剪力墙边缘构件模板体系及其施工方法

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2265943A1 (en) * 1974-03-27 1975-10-24 Noirel Christian Formwork for supporting wall - U-shaped units have end panels which swing inwards for extraction after concreting
KR20080001711A (ko) * 2006-06-29 2008-01-04 충주대학교 산학협력단 무지주 공법에 의한 지하 옹벽 시공방법
US20090308011A1 (en) * 2006-07-21 2009-12-17 Phil-Insul Corporation Insulated concrete form panel reinforcement
US8360389B2 (en) * 2007-02-13 2013-01-29 Peri Gmbh Formwork systems for forming corners and T intersections using formwork elements comprising centrally lined up tie holes
CN103498419A (zh) * 2013-10-17 2014-01-08 中铁六局集团有限公司 箱梁钢制芯模及其施工方法
CN203755264U (zh) * 2014-02-25 2014-08-06 宋仲华 一种基于曲线溢流面的闸门墩及其门槽的浇筑成型模具
CN203924692U (zh) * 2014-04-22 2014-11-05 江苏天向新型材料科技有限公司 一种三向t型墙墙体模板
CN207878928U (zh) * 2017-06-28 2018-09-18 中建三局集团有限公司 一种填充墙砌体构造柱定型钢模
CN207672558U (zh) * 2017-12-14 2018-07-31 中铁二院工程集团有限责任公司 一种铁路路堤钻孔灌注桩桩板墙结构
CN108589769A (zh) * 2018-05-07 2018-09-28 安徽省公路桥梁工程有限公司 一种超长嵌岩t形组合式柱板高挡墙施工方法
CN110409491A (zh) * 2019-08-07 2019-11-05 上海建工二建集团有限公司 桩板式挡土墙整体浇筑模板结构及其施工方法
CN210857267U (zh) * 2019-08-07 2020-06-26 上海建工二建集团有限公司 桩板式挡土墙整体浇筑模板结构

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114482117A (zh) * 2021-12-10 2022-05-13 中交第一航务工程局有限公司 水下大体积混凝土挡墙施工方法
CN114482117B (zh) * 2021-12-10 2024-01-26 中交第一航务工程局有限公司 水下大体积混凝土挡墙施工方法
CN114482054A (zh) * 2022-01-07 2022-05-13 北京城建五建设集团有限公司 斜面褥垫层浇筑模体系及施工方法
CN114934672A (zh) * 2022-03-09 2022-08-23 五冶集团上海有限公司 坡屋面房屋中天沟的新型支模方法
CN114837172A (zh) * 2022-05-19 2022-08-02 中国建筑第八工程局有限公司 抗滑桩接桩部位与桩间板施工的衔接装置及施工方法
CN114960306A (zh) * 2022-05-27 2022-08-30 中铁二院成都勘察设计研究院有限责任公司 一种路基支护结构
CN114960306B (zh) * 2022-05-27 2023-05-12 中铁二院成都勘察设计研究院有限责任公司 一种路基支护结构

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