Long-span reinforced concrete inner support structure of rectangular deep foundation pit and construction method of structure

A reinforced concrete and support structure technology, which is applied in basic structure engineering, excavation, construction, etc., can solve the problems of difficulty in reaching the level of the foundation pit, vertical two-way force balance, and single support form, and achieves small deformation and convenient construction. , the effect is remarkable

Inactive Publication Date: 2013-10-02

广西建工第五建筑工程集团有限公司

9 Cites 32 Cited by

AI-Extracted Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a rectangular deep foundation pit large-span reinforced concrete internal support structure, which solves the problem that the su...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Abstract

The invention discloses a long-span reinforced concrete inner support structure of a rectangular deep foundation pit, which comprises a foundation pit edge breast wall retaining structure, a plurality of layers of inner support three-dimensional timbering structures with steel structure support columns, and a top beam, wherein each inner support three-dimensional timbering structure comprises a foundation pit corner part structure, a foundation pit middle part symmetrical and opposite support structure, and longitudinal beams; each foundation pit middle part symmetrical and opposite support structure comprises a cross beam and two small inclined struts positioned at the two ends of the cross beam; the longitudinal beams are beams which are parallel to long edges of the foundation pit and are positioned at the middle part of the foundation pit; the steel support columns directly reach below the bottom of the foundation pit; the bottoms of the steel structure support columns are anchored by placed concrete; ring beams are arranged at parts where the cross beams, the longitudinal beams and the steel structure support columns at the middle part of the foundation pit are intersected; a support waist beam is arranged at a connection part between the inner support three-dimensional timbering structure and the middle part of the foundation pit edge breast wall retaining structure; and the cross beams, longitudinal beams, the ring beams and the waist beam of the inner support three-dimensional timbering structure are reinforced concrete or combined type large steel frame structures. The inner support structure is simple and visual in design, convenient to construct, large in support span, and significant in timbering effect.

Application Domain

Excavations

Technology Topic

RebarReinforced concrete +4

Image

Examples

Experimental program(2)

Example Embodiment

[0053] Example one

[0054] A large-span reinforced concrete inner support structure for a rectangular deep foundation pit, such as figure 1 As shown, the large-span reinforced concrete internal support structure of the rectangular deep foundation pit includes a retaining structure 7 on the side of the foundation pit, an internal support three-dimensional support structure including a steel support column 10, and a crown beam. The crown beam is an internal support three-dimensional The inner supporting three-dimensional supporting structure described by the ring beam at the top of the retaining structure at the top of the retaining structure and the side wall of the foundation pit has 2 layers, each layer includes the corner structure of the foundation pit, the symmetrical supporting structure in the middle of the foundation pit and the longitudinal Beam 6

[0055] The corner structure of the foundation pit includes a large diagonal brace 1 located at the corner of the foundation pit. On the large diagonal brace 1, there is a triangular stable support 21. The vertices of the triangular stable support 21 are formed by the side line or the extension line of the side line of the foundation pit. The intersection point of the 90° bisector of the second outer side and the second large diagonal brace 12, the radial ends of both sides intersect the outermost large diagonal brace 11 (see figure 1 , figure 2 ).

[0056] The symmetrical support structure in the middle of the foundation pit includes a beam 5 and two small diagonal braces 3 located at the two ends of the beam 5. The beam 5 is a beam parallel to the short side of the foundation pit in the middle of the foundation pit. Side retaining wall retaining structure 7 is fixedly connected, two small diagonal braces 3 are symmetrically located on both sides of the beam, one end of the two small diagonal braces 3 is fixedly connected to the cross beam, and the other end is fixedly connected to the retaining structure of the side retaining wall of the foundation pit (see figure 1 , figure 2 , Figure 5 ); The longitudinal beam 6 is a beam parallel to the long side of the foundation pit in the middle, the steel support column 10 is directly below the bottom of the foundation pit, the bottom of the steel support column is a steel support column anchored by pouring concrete There is a ring beam 4 at the intersection of the longitudinal beam 6, the cross beam 5 and the steel support column 10 in the middle of the foundation pit.

[0057] There are two kinds of ring beams 4, one is the reinforcing steel bar 41 (see Figure 7-1 ), the other is a reinforced structure that is retained at the same time as the steel support column; the reinforced structure is circular (see Figure 7-2 ), can also be a circular square (see Figure 7-3 ), it can also be other circular polygons.

[0058] There is also a supporting waist beam 9 at the middle of the connection between the inner supporting three-dimensional supporting structure and the retaining structure of the side wall of the foundation pit, and the supporting waist beam 9 is simultaneously connected to the cross beam 4 and the retaining structure 7 of the side wall of the foundation pit.

[0059] The cross beams, longitudinal beams, ring beams and waist beams of the internal support three-dimensional support structure are collectively called support beams, and they are all reinforced concrete internal support structures.

[0060] The retaining structure of the side wall of the foundation pit can be an underground continuous wall, a supporting row of piles, or a steel sheet pile.

[0061] As a variation of the embodiment of the present invention, the cross beams, longitudinal beams, ring beams and waist beams of the internal support three-dimensional support structure can also be combined large steel frame structures or new materials with rigidity that meet the requirements of the foundation pit. Frame structure made into.

[0062] As a variation of the embodiment of the present invention, the number of layers n of the internal support three-dimensional support structure can also be increased or decreased. Generally, the value range of n is: n is an integer greater than or equal to 1 and less than or equal to 30, as required , Or more layers.

[0063] As a variation of the embodiment of the present invention, when the area of the foundation pit is not large or the length of the foundation pit is not greater than the width of the foundation pit, for example, when the structure is approximately rectangular, the longitudinal beam 6 may not be used.

Example Embodiment

[0064] Example two

[0065] A method for constructing a large-span reinforced concrete inner support structure for a rectangular deep foundation pit. The construction process includes:

[0066] A. Overall preparation

[0067] First, the construction of the retaining structure 7 on the side of the foundation pit is carried out at the same time as the construction of the steel support column. The steel support column 10 is extended into the soil by means of bored piles, and the bottom 101 of the steel support column is anchored by concrete pouring (see image 3 , Image 6 ), when the strength of the anchored concrete at the bottom is sufficient, backfill and compact with earth; the retaining structure of the side wall of the foundation pit can be an underground continuous wall or a supporting row of piles or a steel sheet pile;

[0068] B. Carry out single-layer construction of internal support three-dimensional support structure

[0069] When the strength of the retaining structure of the side wall of the foundation pit is sufficient, the soil can be excavated for the construction of the crown beam and the first inner support beam;

[0070] The general process is as follows:

[0071] ① The earthwork is excavated to the bottom of the bottom of the first inner support beam;

[0072] ②Measure, elastic line, and position the support beams of this layer according to the structural scheme of the internal support three-dimensional support structure described in Example 1. The support beams of this layer include the corner structure of the foundation pit, the symmetrical support structure in the middle of the foundation pit and Stringer 6;

[0073] ③ Carry out earthwork compaction and construction of beam bottom cushion;

[0074] ④ Lay plastic film to prevent the cushion layer from sticking to the bottom of the beam;

[0075] ⑤Binding the support beam reinforcement;

[0076] ⑥ Install beam side form template;

[0077] ⑦Pour concrete and reserve blasting holes for removing reinforced concrete supporting beams;

[0078] ⑧Conservation;

[0079] ⑨Excavate the earth after the strength of the supporting beam reaches 80%;

[0080] ⑩ Demoulding.

[0081] C. According to the method of step B, carry out the construction of the support beams from the second layer to the nth layer; the value range of the n is: n is an integer greater than or equal to 1 and less than or equal to 30.

[0082] In the above process, the structural scheme of the internal support three-dimensional support structure to position the support beams of this layer is carried out according to the force principle of the large-span reinforced concrete internal support structure of the rectangular deep foundation pit of the present invention, which includes:

[0083] a. Assuming the number of layers, span and cross-section of the supporting beam, after determining the excavation depth of the foundation pit and the thickness of the retaining wall, the horizontal pressure per unit length on the surrounding beam and the axial force concentrated on the supporting beam are calculated. The size of the axial force on the beam and its own weight are used to calculate the reinforcement of the supporting beam and the stability check. After such repeated assumptions and check calculations, the section and reinforcement of the supporting beam can be finally determined;

[0084] b. Then determine the spacing and span of the internal supports according to the foundation piles, the size of the force, the cross-section of the internal support and the reinforcement; the number of internal supports required is determined by factors such as the size of the earth pressure, the depth of the foundation pit, the number of basement floors, and the position of the floor. , Most of the final internal support plan needs to go through multiple checks to make the foundation pit force system reach a stable structure.

[0085] The force principle of the large-span reinforced concrete inner supporting structure of the rectangular deep foundation pit of the present invention is:

[0086] 1) The horizontal force of the internal support: the earth pressure is transmitted to the retaining structure of the retaining wall, then to the reinforced concrete ring beam, and finally to the reinforced concrete internal support connected to it, and both ends of the internal support are connected to the foundation On the reinforced concrete ring beams on both sides of the retaining structure of the pit side wall, so that the earth pressures of the same magnitude and opposite directions on both sides can be offset to form the best force system.

[0087] 2) The vertical force of the internal support: the vertical force is mainly the self-weight of the support beam, which is transmitted to the foundation through the steel support column.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Login to view more

PUM

Description & Claims & Application Information

We can also present the details of the Description, Claims and Application information to help users get a comprehensive understanding of the technical details of the patent, such as background art, summary of invention, brief description of drawings, description of embodiments, and other original content. On the other hand, users can also determine the specific scope of protection of the technology through the list of claims; as well as understand the changes in the life cycle of the technology with the presentation of the patent timeline. Login to view more.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Login to view more