阅读说明：本技术 一种狭长型风亭结构与主体结构共桩开挖的施工方法 (Construction method for common pile excavation of long and narrow type wind pavilion structure and main body structure ) 是由 徐小涛 李志明 王凯 于 2020-03-16 设计创作，主要内容包括：本发明公开一种狭长型风亭结构与主体结构共桩开挖的施工方法,包括步骤：1)车站先进行围护、主体结构施工,待主体结构施工完毕后,风亭依次进行基坑围闭、基坑降水、基坑开挖、架设支撑施工,至基坑达到设计开挖高度；2)风亭基坑继续向下开挖一定深度,施作加强垫层；3)拆除第二道支撑,破除加强垫层以上所有的共用围护结构；4)依次浇筑风亭结构的底板、侧墙、顶板,待达到设计强度后拆除第一道支撑,顶板覆土回填,施工完毕。本发明通过提高垫层强度的方式,达到提前拆除第二道支撑、凿除共用围护结构的条件,无需在风亭结构底板与主体结构相接处预留后浇带,风亭结构板与主体结构连接可一次浇筑完成,提高了施工效率,缩短了施工工期。(The invention discloses a construction method for common pile excavation of a long and narrow type wind pavilion structure and a main body structure, which comprises the following steps: 1) firstly, enclosing and constructing a main structure at a station, and after the construction of the main structure is finished, sequentially carrying out foundation pit enclosing, foundation pit dewatering, foundation pit excavation and erection support construction on the wind pavilion until the foundation pit reaches a designed excavation height; 2) continuously excavating the wind pavilion foundation pit to a certain depth, and applying a reinforcing cushion layer; 3) removing the second support, and breaking all the shared envelope structures above the reinforcing cushion layer; 4) and pouring a bottom plate, a side wall and a top plate of the wind pavilion structure in sequence, dismantling the first support after the design strength is reached, covering soil on the top plate, backfilling, and finishing construction. According to the invention, the conditions of removing the second support and chiseling the shared enclosure structure in advance are achieved by improving the strength of the cushion layer, a post-pouring belt is not required to be reserved at the joint of the bottom plate of the wind pavilion structure and the main structure, the connection of the wind pavilion structure plate and the main structure can be completed by one-time pouring, the construction efficiency is improved, and the construction period is shortened.)

1. A construction method for common pile excavation of a long and narrow type wind pavilion structure and a main body structure is characterized by comprising the following steps:

1) firstly, enclosing and constructing a main structure of a station, and after the construction of the main structure of the station is finished, sequentially carrying out the working procedures of enclosing a foundation pit, dewatering the foundation pit, excavating the foundation pit and erecting and supporting the foundation pit by the wind pavilion until the foundation pit reaches the designed excavation height;

2) continuously excavating the wind pavilion foundation pit to a certain depth, and applying a reinforcing cushion layer;

3) removing the second support, and breaking all the shared envelope structures above the reinforcing cushion layer;

4) and pouring a bottom plate, a side wall and a top plate of the wind pavilion structure in sequence, dismantling the first support after the design strength is reached, covering soil on the top plate, backfilling, and finishing construction.

2. The method of claim 1, wherein the ratio of the length of the foundation pit to the width of the foundation pit is greater than 2, and the method is designed to use two supports and to erect counter supports on a common enclosure.

3. The method of co-piling and excavating a long and narrow type wind shelter structure and a main body structure according to claim 1, wherein the downward development depth in the step 2) is 20-30 cm.

4. The construction method for co-piling and excavating the elongated wind pavilion structure and the main body structure according to claim 1 or 3, wherein the reinforcing cushion layer in the step 2) is a concrete structure cushion layer which is formed by pouring early strength concrete, contains a certain amount of section steel, tightly props up the enclosing structures on two sides and has certain rigidity.

Technical Field

The invention relates to a construction method for common pile excavation of a long and narrow type wind shelter structure and a main body structure, and belongs to the technical field of subway station construction.

Background

The subway is a traffic form with the largest transportation volume, the most accurate time and the fastest speed in the city, has the advantages of saving land, saving energy, reducing noise, pollution and the like, is a backbone traffic system for city development, but has the problems of long construction period, high construction cost, large influence on urban traffic in the construction process and the like. How to effectively improve the construction efficiency and shorten the construction period is the biggest subject of the current subway construction research.

The subway station construction comprises two parts, namely main structure construction and auxiliary structure construction, wherein the auxiliary structures comprise station wind pavilions, entrances and exits, four small parts on the ground and the like, the station wind pavilions are generally communicated with a station main body station hall layer and do not have partition structure walls, and a wind pavilion foundation pit and a station main body share an enclosure structure. For a single-layer wind pavilion structure mainly based on a soil layer, the depth of a foundation pit is about 10m, and two supports need to be erected in the foundation pit design in order to meet the requirements of deformation and internal force calculation of excavation working conditions.

The contour of part of the station wind pavilion foundation pit is in a long and narrow type limited by the surrounding environment of the ground, and when the wind pavilion foundation pit is constructed in the type, the safety of the foundation pit cannot be ensured only by erecting the inclined strut, and a pair of struts are required to be erected and supported on the main body enclosure structure at the same time. Due to the fact that the second support exists, the shared enclosure structure cannot be chiseled out before the wind pavilion bottom plate is poured, the wind pavilion bottom plate and the station middle plate are in a post-cast strip (or a post-cast pit), after the bottom plate reaches the designed strength, the second support is removed, the shared enclosure structure is chiseled out, the post-cast strip is waterproof, the concrete plate is chiseled, the post-cast strip is poured, and the construction period of the post-cast strip is about half a month. In order to shorten the construction period, it is necessary to deeply research the construction working condition of the common pile of the long and narrow type wind pavilion structure and the main body structure, a safe and reliable construction method is provided, and a certain experience reference is provided for the design and construction of the subway foundation pit.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a construction method for common pile excavation of a long and narrow type wind pavilion structure and a main structure, which can improve the construction efficiency and shorten the construction period.

In order to achieve the purpose, the construction method for the common pile excavation of the long and narrow type wind pavilion structure and the main body structure comprises the following steps:

1) firstly, enclosing and constructing a main structure of a station, and after the construction of the main structure of the station is finished, sequentially carrying out the working procedures of enclosing a foundation pit, dewatering the foundation pit, excavating the foundation pit and erecting and supporting the foundation pit by the wind pavilion until the foundation pit reaches the designed excavation height;

2) continuously excavating the wind pavilion foundation pit to a certain depth, and applying a reinforcing cushion layer;

3) removing the second support, and breaking all the shared envelope structures above the reinforcing cushion layer;

4) and pouring a bottom plate, a side wall and a top plate of the wind pavilion structure in sequence, dismantling the first support after the design strength is reached, covering soil on the top plate, backfilling, and finishing construction.

As an improvement, the long and narrow type wind pavilion structure is characterized in that the ratio of the length of a wind pavilion foundation pit to the width of the foundation pit is larger than 2, two supports are adopted in design, and a pair of supports needs to be erected and supported on a shared enclosure structure.

As a modification, the downward development depth in the step 2) is 20-30 cm.

As an improvement, the reinforced cushion layer in the step 2) is a concrete structure cushion layer with certain rigidity which is formed by adopting early strength concrete, containing a certain amount of profile steel, tightly jacking the enclosing structures on two sides and pouring.

The existing common long and narrow single-layer wind booth structure and the main structure need to be provided with a post-cast strip during common pile construction, the post-cast strip is narrow in space, easy to accumulate water, difficult in operation condition and difficult in construction quality guarantee, and a post-cast strip construction process is added, so that the construction investment needs to be increased, and the construction period needs to be prolonged. According to the method, the conditions of removing the second support in advance and chiseling the shared enclosure structure are achieved by improving the strength of the cushion layer, a post-pouring belt does not need to be reserved on the bottom plate of the wind pavilion structure, the wind pavilion structure plate can be poured at one time, the construction efficiency is improved, and the construction period is shortened.

Drawings

FIG. 1 is a schematic view of the construction of step 1) in the present invention;

FIG. 2 is a schematic view of the construction of step 2) in the present invention;

FIG. 3 is a schematic view of the construction of step 3) in the present invention;

FIG. 4 is a schematic view of the construction of step 4) in the present invention;

FIG. 5 is a schematic diagram illustrating the calculation conditions and calculation results of the reinforcement mat according to the embodiment of the present invention;

FIG. 6 is a construction sequence diagram of a foundation pit according to an embodiment of the present invention; in the figure, (1) is excavated to-1.65 (depth 1.65) m; (2) installing a 1 st support (anchor) at a position of-1.25 (depth of 1.25) m; (3) excavating to-6.55 (depth 6.55) m; (4) installing a 2 nd support (anchor) at a position of-6.25 (depth 6.25) m; (5) excavating to-10.35 (depth 10.35) m; (6) changing support at-10.15 (depth 10.15) m; (7) changing support at-5.45 (depth 5.45) m;

FIG. 7 is a diagram illustrating a stress condition of a foundation pit according to an embodiment of the present invention; in the figure, (a) a force envelope graph (K is 2.88-32.67); (b) a displacement envelope diagram (-1.6-11.9); (c) a bending moment envelope diagram (-550.9-577.2); (d) a shear envelope diagram (-467.4-460.1);

in the figure: 1. station major structure, 2, envelope, 3, first support, 4, pavilion structure, 5, second support, 6, pavilion envelope, 7, enclosing purlin, 8, reinforcing cushion.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below. It should be understood, however, that the description herein of specific embodiments is only intended to illustrate the invention and not to limit the scope of the invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the terms used herein in the specification of the present invention are for the purpose of describing particular embodiments only and are not intended to limit the present invention.