CN102444130B - Support replacing construction method in deep foundation pit project - Google Patents

Abstract

The invention discloses a construction method for rapid brace replacement in deep foundation pit engineering, which comprises step 1) arranging a first brace replacement rib between the basement concrete floor and foundation pit support structure, and a plurality of brace replacement ribs arranged at intervals , the outer side of each first replacement rib is connected to the inner side of the foundation pit support structure, and the inner side is connected to the basement concrete floor; the first replacement rib and the basement concrete floor are constructed at the same time, and the basement concrete floor and After the formwork removal of the first supporting rib, remove the last temporary support at the bottom of the foundation pit, backfill and tamp the earthwork between the adjacent first supporting ribs; there are two types of supporting ribs, the first It is a horizontal concrete rib, and the second type is a T-shaped concrete rib. The middle vertical plate of the T-shaped concrete rib is perpendicular to the foundation pit support structure. The invention also discloses another quick support replacement method using vertical concrete ribs as the support replacement ribs. The invention can relatively easily control the construction period, construction quality and safety, and is suitable for the supporting system of ultra-deep and ultra-large foundation pits.

Description

The construction method of rapid support replacement in deep foundation pit engineering

technical field

The invention relates to a construction method for brace replacement in deep foundation pits, in particular to a construction method for fast brace replacement in ultra-deep and super-large foundation pit construction. the

Background technique

The support replacement in deep foundation pit engineering is to take certain technical measures under specific conditions to gradually replace the internal support structure system that plays the role of temporary support, so as to ensure that the construction can continue safely and smoothly after the temporary internal support is removed. , its essence is the safe and orderly adjustment, transfer and redistribution of stress. the

The principle of support replacement: Let the part of the stress generated by the removal of the inner support of the support pile be transmitted to the third party with sufficient bearing capacity through the force transmission member, so as to achieve a new force balance. In addition to using rigid supports (diagonal braces, horizontal supports) to connect the support piles and the basement structure to control deformation and realize stress transfer, it can also be realized by backfilling. During the conversion process, the enclosure system itself still plays a considerable supporting role. the

At present, there are two common ways to replace braces in deep foundation pits: one is to set diagonal braces, which has a short construction period and less investment, but it is difficult to select support points and it is difficult to arrange them comprehensively (especially at the four corners of the building). The overall effect of brace replacement Poor, easy to be damaged, and often due to the short distance between the support pile and the wall, the diagonal brace often needs to pass through the wall to connect with the corbel of the basement concrete floor, which will increase the difficulty of waterproof construction, and the removal of the diagonal brace will also delay the construction period. The other is to directly use horizontal rigid components to replace the braces and connect the beams, and finally realize the stress of the supporting piles through the floor beams. Its advantages are good stress effect, simple construction and no need for demolition construction, so it is more suitable for projects with tight construction schedules. Since the internal force of the foundation pit is borne by the cast-in-place floor beams and slabs, higher requirements are put forward for the structural safety of the project itself, and necessary technical measures must be taken to ensure the smooth progress of the construction. The conventional construction method is to remove the formwork after pouring the bottom slab concrete, and backfill the gap between the bottom slab and the support piles with earthwork (the other kind of backfill is gravel to replace the backfill in the pit, which is characterized by the force transmission belt. The force uniformity is good, but in actual construction, the waterproofing construction is often involved late, and the density of the backfill is difficult to control, and the internal force transmission of large foundation pits cannot be guaranteed, so the backfill is used as a force transmission belt only for auxiliary purposes ) and compacted, and then pour a 250-400MM thick concrete horizontal ring on top of the backfill as a replacement support. The removal process of the temporary support system can only be carried out after this part of the concrete reaches the design required strength. However, for very large deep foundation pits or projects with extremely complex structural forces, this method has complex construction levels, difficult practical operations, and a long construction period, and the safety risk probability of the foundation pit enclosure system structure increases significantly, which seriously affects the foundation. The pit construction period has caused the support replacement technology to be an important and prominent problem in the construction of deep foundation pits. the

Contents of the invention

In order to solve the technical problems existing in the known technology, the present invention provides two construction methods for rapid support replacement in deep foundation pit engineering. The two construction methods can relatively easily control the construction period, construction quality and safety, and can be suitable for ultra-deep and super-large The support system of the foundation pit. the

A technical scheme that the present invention takes for solving the technical problems existing in the known technology is: a kind of quick support replacement construction method in deep foundation pit engineering, including step 1) the construction of the first support replacement rib:

The first support ribs are arranged between the basement concrete floor and the foundation pit support structure, and there are multiple intervals. The outer side of each first support rib is connected with the inner side of the foundation pit support structure. The inner side is connected with the concrete floor of the basement;

The first replacement rib and the concrete floor of the basement are constructed at the same time. After the basement concrete floor and the first replacement rib are demolished, the bottom temporary support at the bottom of the foundation pit is removed, and the adjacent first replacement rib Backfill the earthwork between the slabs and compact them;

There are two kinds of support ribs, the first type is horizontal concrete ribs, the second is T-shaped concrete ribs, and the middle vertical plate of the T-shaped concrete ribs is perpendicular to the support structure of the foundation pit. the

Above-mentioned construction method also comprises step 2) the construction of the second road replacement rib:

The second replacement rib is arranged between the roof of the bottom floor of the basement and the foundation pit support structure, and there are multiple intervals, and the outer side of each second replacement rib is connected to the foundation pit support structure. The inner side is connected, and the inner side is connected with the wall panel of the basement;

All the second ribs are constructed at the same time as the wall panels of the basement; before the construction of the second ribs, earthwork is backfilled and compacted on the first ribs;

After the basement wall panels and the second replacement ribs are removed from the formwork, the second temporary support of the foundation pit is removed, and earthwork is backfilled and compacted between the adjacent second replacement ribs. the

Above-mentioned construction method also comprises step 3) the construction of the 3rd road replacement rib plate:

The third replacement rib is arranged between the roof below the first floor of the basement and the foundation pit support structure. There are multiple intervals, and the outer side of each third replacement rib is connected to the inner side of the foundation pit support structure. The inner side is connected with the wall panels of the basement; all the third support ribs are constructed simultaneously with the wall panels of the basement, and the construction steps are the same as step 2). the

Another technical solution adopted by the present invention to solve the technical problems existing in the known technology is: a quick support replacement construction method in deep foundation pit engineering, using vertical concrete ribs as the support replacement ribs, vertical concrete ribs The panels are arranged between the basement wall panel and the foundation pit support structure, and are arranged at intervals, and the outer side of each vertical concrete rib is connected with the inner side of the foundation pit support structure, and the inner side is connected with the basement wall panel;

The vertical concrete ribs and the basement wall panels are constructed at the same time. After the basement wall panels and vertical concrete ribs are removed from the formwork, the temporary supports at the corresponding parts are removed, and earthwork is backfilled and compacted between adjacent vertical concrete ribs. the

The advantages and positive effects of the present invention are: the ribs are used to replace the braces, and the ribs and the basement concrete floor/wallboard are simultaneously molded, poured and maintained at the same time, and the floor/wallboard concrete reaches strength, and the braced ribs are replaced It has also reached the strength, and naturally it also plays the role of changing braces. The underground structure can be continuously constructed without waiting for earthwork backfilling, without affecting the construction period of the underground project. Control the construction period, project quality and production safety, and is suitable for the support system of ultra-deep and super-large foundation pits. Moreover, the invention is convenient for process arrangement and coordination, and convenient for construction; the construction process is safe and reliable, and convenient for safety management. the

Description of drawings

Fig. 1 is the schematic diagram of the horizontal concrete rib plate that the present invention applies;

Fig. 2 is the local plan view of the application of horizontal concrete rib construction in the present invention;

Fig. 3 is the elevation view of the application of horizontal concrete rib construction in the present invention;

Fig. 4 is the vertical concrete floor schematic diagram of application of the present invention;

Fig. 5 is the local plan view of the application of vertical concrete rib construction in the present invention;

Fig. 6 is the elevation view of the application of vertical concrete rib construction in the present invention;

Fig. 7 is the schematic diagram of the T-shaped concrete rib plate that the present invention applies;

Fig. 8 is the local plane view of the application of T-shaped concrete rib construction in the present invention;

Fig. 9 is an elevation view of the construction of the present invention using T-shaped concrete ribs. the

Detailed ways

In order to further understand the invention content, characteristics and effects of the present invention, the following examples are given hereby, and detailed descriptions are as follows in conjunction with the accompanying drawings:

Embodiment 1, please refer to FIGS. 1 to 3 and FIGS. 7 to 9 . the

A quick support replacement construction method in deep foundation pit engineering:

1) Construction of the first replacement rib: 

The first replacement rib 12 is arranged between the basement concrete floor 5 and the foundation pit support structure 1, and is arranged at intervals, and the outer side of each first replacement rib 12 is connected to the foundation pit support structure 1. The inner side is connected, and the inner side is connected with the concrete floor 5 of the basement;

The first replacement rib 12 is constructed at the same time as the basement concrete floor 5, that is, the basement concrete floor 5 is molded at the same time, poured at the same time, and maintained at the same time. The strength of the mold has played a supporting role, and the dismantling process of the temporary support system can be arranged. The temporary support corresponding to this is the bottom temporary support at the bottom of the foundation pit, and the earthwork is backfilled and compacted between the adjacent first replacement ribs 12 . the

2) Construction of the second replacement rib:

The second supporting rib 22 is arranged between the top plate 6 of the bottom floor of the basement and the foundation pit support structure 1, and is arranged at intervals, and the outer side of each second supporting rib 22 is in contact with the The inner side of the support structure 1 is connected, and the inner side is connected with the wall panel 4 of the basement;

All the second supporting ribs 22 are constructed simultaneously with the basement wall panels 4; that is, when the basement wall panels 4 are being constructed, the second supporting ribs 22 and the basement wall panels 4 are molded at the same time, concrete is poured at the same time, and maintenance is performed at the same time. After reaching the demolition strength, the ribs 22 have played a supporting role, and the removal process of the temporary support system can be arranged. The temporary support corresponding to this is the second temporary support of the foundation pit, and the earthwork 3 is backfilled and compacted between the adjacent second replacement ribs 22 . Before the construction of the second rib, backfill the earthwork on the first rib and compact it. the

3) Construction of the third replacement rib:

The third replacement rib is arranged between the roof below the first floor of the basement and the foundation pit support structure. There are multiple intervals, and the outer side of each third replacement rib is connected to the inner side of the foundation pit support structure. The inner side is connected with the wall panels of the basement; all the third support ribs are constructed simultaneously with the wall panels of the basement; the construction steps are the same as step 2). The temporary support corresponding to the third replacement rib is usually the last temporary support of the foundation pit. So far, all the support replacement of the foundation pit has been completed. the

In the above steps, there is backfilled and compacted earthwork 3 between the adjacent upper and lower ribs. the

As for how many support replacements are needed, it should be determined according to the specific conditions of the foundation pit. For example, if the basement has only one floor, only step 1) needs to be completed; if the basement has two floors, only step 1) and step 2) need to be completed; There are three floors in the basement, and it needs to be determined whether it is necessary to proceed to step 3) depending on the specific situation. the

There are two structures of the above-mentioned replacement ribs:

The first type is a horizontal concrete rib plate, which is a horizontal concrete plate formed by pouring; the second type is a T-shaped concrete rib plate, in which the middle vertical plate is perpendicular to the support structure of the foundation pit. the

Embodiment 2, please refer to Fig. 4 to Fig. 6 . the

A construction method for rapid brace replacement in deep foundation pit engineering: the method uses vertical concrete ribs as the brace replacement ribs, which are vertical concrete slabs formed by pouring and perpendicular to the foundation pit support structure 1 .

The vertical concrete ribs 2 are arranged between the basement wall board 4 and the foundation pit support structure 1, and are arranged in multiples at intervals, and the outer side of each vertical concrete rib 2 is connected with the inner side of the foundation pit support structure 1 , the inner side is connected with the basement wall panel 4;

The vertical concrete ribs 2 and the basement wall panels 4 are constructed at the same time, that is, the basement wall panels 4 are molded at the same time, poured at the same time, and maintained at the same time. When the concrete of the basement wall panels 4 reaches the formwork removal strength, it also reaches the formwork removal strength. , has played a supporting role, the removal process of the temporary support system can be arranged. Earthwork 3 is backfilled between adjacent vertical concrete ribs 2 and compacted. the

Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative and not restrictive. Those of ordinary skill in the art Under the enlightenment of the present invention, people can also make many forms without departing from the purpose of the present invention and the scope of protection of the claims, and these all belong to the protection scope of the present invention. the

Claims (1)

1. the fast support replacing job practices in a deep-foundation pit engineering, it is characterized in that, adopt vertical concrete floor as the support replacement floor, vertical concrete floor is arranged between basement wallboard and foundation pit supporting construction, vertical concrete floor is vertical with foundation pit supporting construction, for spaced a plurality of, the outside of each vertical concrete floor is connected with the inboard of foundation pit supporting construction, inboardly with the basement wallboard, is connected;

Vertical concrete floor and basement wallboard are constructed simultaneously, after basement wallboard and vertical concrete floor form removal, remove the temporary supporting of corresponding site, the backfill earthwork compacting between adjacent vertical concrete floor.

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