CN114250791A

CN114250791A - Construction method of deep foundation pit support replacing system

Info

Publication number: CN114250791A
Application number: CN202111682490.4A
Authority: CN
Inventors: 倪胜跃; 梁百超; 杨建松; 章雷畏; 李步利
Original assignee: Zhejiang Henghong Construction Co ltd
Current assignee: Zhejiang Henghong Construction Co ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-03-29
Anticipated expiration: 2041-12-31
Also published as: CN114250791B

Abstract

The invention relates to a construction method of a deep foundation pit support changing system, which comprises the following steps: constructing a micro-expansion concrete zone, and reserving a slot group; step two, assembling the steel pipe upright post; step three, assembling a support replacing platform; fourthly, arranging steel base plates on the foundation pit enclosure structures and the underground outdoor walls at the equal-height positions of the horizontal jack groups; fifthly, controlling the displacement of the partition plate within a set range through displacement monitoring equipment; step six, backfilling a foam concrete layer in a fertilizer groove above the micro-expansion concrete belt; removing the temporary support, the support changing platform, the horizontal jack set and the steel base plate of the layer; step eight, pouring the slot hole group again; and step nine, repeating the step two to the step eight until the construction of the deep foundation pit supporting and support changing system is completed. The method and the device can effectively control the construction period and the engineering quality, and achieve the quick and safe support changing effect.

Description

Construction method of deep foundation pit support replacing system

Technical Field

The invention relates to the technical field of constructional engineering, in particular to a construction method of a deep foundation pit supporting and support replacing system.

Background

The foundation pit supporting system is a temporary structure, has small safety reserve and has larger risk. In the deep foundation pit supporting engineering, when the basement is constructed, the inner supports must be gradually removed, and in order to ensure the safety of the foundation pit, the supports must be removed after horizontal force is converted through support replacement. The traditional foundation pit support replacing method is complex in construction operation, low in construction efficiency, long in construction period and not easy to control, the whole effect of support replacement is not ideal, the whole effect is easy to damage, and potential safety hazards exist.

Therefore, the deep foundation pit supporting and replacing system and the construction method which are reasonable in structure, safe, stable, simple and efficient to construct are urgently needed to be needed.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a construction method of a deep foundation pit support replacing and supporting system.

In order to realize the purpose of the invention, the invention adopts the following technical scheme: the construction method of the deep foundation pit support changing system comprises the following steps:

firstly, after a foundation cushion layer is constructed at the bottom of a foundation pit, pouring a bottom plate, then pouring and constructing the outer wall of a basement at the bottom layer, backfilling micro-expansion concrete in a fertilizer groove between a foundation pit support structure and the bottom plate to form a micro-expansion concrete zone, and reserving a groove hole group; the foundation pit support structure is provided with a first temporary support and a second temporary support;

step two, sleeving plastic protection pipes on the steel pipe stand columns, inserting the lower parts of the steel pipe stand columns into each slotted hole of the slotted hole group, enabling the support changing platform to reach the designed height after installation, and bolting and installing a fixing and connecting tie rod at the upper part of each group of steel pipe stand columns;

thirdly, bolting and installing a platform plate through a sealing bolt rod on the top of the steel pipe upright post, and bolting and installing horizontal jack sets on two sides of a partition plate in the middle of the platform plate by utilizing fastening bolts to form a support changing platform;

fourthly, arranging steel base plates on the foundation pit enclosure structures and the underground outdoor walls at the equal-height positions of the horizontal jack groups;

placing displacement monitoring equipment on the basement main body beam plate to monitor the displacement change of the partition plate, controlling the bidirectional force of the horizontal jack group and jacking the horizontal jack group on the steel base plates at two sides, so that the displacement of the partition plate is controlled within a set range;

step six, backfilling a foam concrete layer in a fertilizer groove above the micro-expansion concrete belt, wherein the backfilling height is up to the top of the plastic protection pipe;

removing the temporary support, the support changing platform, the horizontal jack set and the steel base plate of the layer;

step eight, after a new layer of basement outer wall is constructed, pouring concrete into the plastic protection pipe to a set height to form a second slotted hole group, and installing a protection pipe joint at the top of the plastic protection pipe;

and step nine, repeating the step two to the step eight, and completing multiple foam concrete layer backfilling from bottom to top until the construction of the deep foundation pit supporting and replacing support system is completed.

The working principle and the beneficial effects are as follows: 1. compared with the prior art, the deep foundation pit supporting and replacing system has the advantages that the supporting and replacing platform is adopted for replacing the supports layer by layer, the structure is reasonable, the manufacturing and the installation are convenient, the reinforced concrete supporting and replacing structure does not need to be poured, the construction is synchronous with the supporting and replacing backfill, the construction period of underground engineering is not influenced, the construction period and the engineering quality can be effectively controlled, and the quick and safe supporting and replacing effect is achieved;

2. the invention adopts the micro-expansion concrete belt and the foam concrete to carry out support-changing backfill, the integral backfill structure has good waterproof and seepage-proof performance, and meanwhile, the porosity of the foam concrete ensures that the foam concrete has low elastic modulus, thereby ensuring that the foam concrete has good absorption and dispersion effects on impact load, better transferring the internal force of the foundation pit without being damaged;

3. the plastic protection pipe is low in cost, not only protects the steel pipe stand column, but also can be used for continuing the slotted hole group, so that the mounting of the support changing platform is convenient, the construction efficiency is improved, and the construction period is saved.

Further, in the seventh step, the concrete dismantling step is as follows:

s1, removing the horizontal jack set and the steel backing plate;

s2, removing the platform board;

s3, removing the fixed tie bar at the top of the steel tube upright post;

and S4, pulling out the steel pipe upright post and leaving the plastic protection pipe.

Further, in the fifth step, the displacement monitoring equipment is a total station.

Furthermore, in the second step, a plurality of connecting lug plates are arranged at the upper part of the steel pipe upright post, and the steel pipe upright post and the fixed connecting tie rod are tightly connected through the connecting lug plates and the connecting bolts.

Furthermore, the fixed connecting tie rod comprises a long rod, a short rod and a cross rod, the long rod is connected with the steel pipe stand column on the long side of the support platform, the short rod is connected with the steel pipe stand column on the short side of the support platform, and the cross rod is connected with the four steel pipe stand columns and is in an X shape.

Furthermore, the height of each horizontal jack group is equal to the height of the center of the main beam slab of the basement on the floor.

Furthermore, four slotted holes are used as a group in the slotted hole group of each layer of foam concrete layer, and a plurality of groups are uniformly arranged at intervals.

Further, in the first step, micro-expansion concrete is backfilled in the fertilizer groove between the foundation pit support structure and the bottom plate to half height or nearly half height of the outer wall of the basement at the bottom layer.

Further, the temporary support includes a first temporary support and a second temporary support.

The basement is constructed by applying the construction method of the deep foundation pit supporting and support replacing system.

Drawings

FIG. 1 is a schematic view of a deep foundation pit support replacement system of the present invention;

FIG. 2 is a schematic structural view of a change brace platform;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a schematic view of the arrangement of the fastening tie bar;

FIG. 5 is a schematic cross-sectional view of a micro-expansive concrete strip;

FIG. 6 is a schematic layout diagram of a first support changing system for deep foundation pit support;

FIG. 7 is a schematic layout view of a second support changing system for deep foundation pit support;

fig. 8 is a construction process flow chart of the deep foundation pit support replacing system.

In the figure, 1, a foundation pit support structure; 2. a second temporary support; 3. a first temporary support; 4. a displacement monitoring device; 5. a basement main body beam slab; 6. a basement exterior wall; 7. a base plate; 8. a base mat layer; 9. a steel backing plate; 10. replacing the support platform; 11. a foamed concrete layer; 12. a micro-expansive concrete strip; 13. a slot group; 14. protecting the pipe joint; 15. a set of horizontal jacks; 16. a partition plate; 17. fastening a bolt; 18. a fixed tie bar; 19. a sealing tie rod; 20. a platform plate; 21. a plastic protection tube; 22. a steel pipe upright post; 23. a long rod; 24. a short bar; 25. a cross bar; 26. connecting a bolt; 27. the ear plate is connected.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.

It will be understood by those skilled in the art that in the present disclosure, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, the above terms should not be construed as limiting the present invention.

In the case of the example 1, the following examples are given,

as shown in fig. 8 (fig. 8 shows construction steps of a simplified version, and the content of the description is taken as a reference), the construction method of the deep foundation pit support changing system comprises the following steps:

step one, as shown in fig. 1 and 5, after a foundation cushion layer 8 is constructed at the bottom of a foundation pit, pouring construction is carried out on a bottom plate 7 of a basement, then an outer wall 6 of the basement at the bottom layer and a main beam plate 5 of the basement are poured and constructed, and then micro-expansion concrete is backfilled in a fertilizer groove between a foundation pit support structure 1 and the bottom plate 7 to the half height or the approximate half height of the outer wall 6 of the basement at the bottom layer to form a micro-expansion concrete zone 12, and a groove hole group 13 is reserved; the foundation pit support structure 1 is provided with a first temporary support 3 and a second temporary support 2, and a third temporary support and a fourth temporary support can be arranged according to the actual height;

the foundation pit support structure 1 is arranged on one side of a foundation pit fertilizer groove, the basement outer wall 6 and the bottom plate 7 are arranged on the other side of the foundation pit fertilizer groove, the foundation cushion layer 8 is positioned at the bottoms of the foundation pit fertilizer groove and the bottom plate 7, the basement outer wall 6 is positioned above the bottom plate 7, and the basement main body beam plates 5 are arranged on one side of the basement outer wall 6, which is far away from the foundation pit fertilizer groove, at intervals and are in one-to-one correspondence with the foam concrete layers 11; in this embodiment, if the basement outer wall 6 encloses a rectangle, the foundation pit support structure 1 is also a rectangle, and it encloses outside the basement outer wall 6, and the clearance between the two is just a fertilizer trough, or a foundation pit fertilizer trough, and the purpose of this application lies in changing the system of propping through the support and come the layering concreting to construct in this fertilizer trough.

Wherein, the slotted hole group 13 of each layer of foam concrete layer 11 takes four slotted holes as a group, and a plurality of groups are arranged at even intervals, and the slotted hole group 13 of the micro-expansion concrete belt 12 is also the same. And the depth and the aperture of the slotted hole group 13 reserved by the foam concrete layer 11 and the micro-expansion concrete belt 12 meet the stability of the steel tube upright post 22 after being inserted.

After the outer wall 6 and the basement main body beam slab 5 are poured each time, the foam concrete layer 11 is needed to support, and the support of the fertilizer tank is realized by replacing the support platform 10 before the foam concrete layer 11 is constructed again.

Step two, as shown in fig. 4, sleeving a plastic protection pipe 21 on a steel pipe upright column 22, inserting the lower part of the steel pipe upright column 22 into each slotted hole of the slotted hole group 13, wherein four steel pipe upright columns 22 form a group to ensure that the support changing platform 10 reaches the designed height after being installed, and then bolting and installing a fixed connecting tie bar 18 at the upper part of each group of steel pipe upright columns 22;

in this step, a plurality of connecting ear plates 27 are arranged on the upper part of the steel tube upright post 22, the steel tube upright post 22 and the fixing connecting rod 18 are fastened and connected through the connecting ear plates 27 and the connecting bolts 26, the fixing connecting rod 18 comprises a long rod 23, a short rod 24 and a cross rod 25, the long rod 23 is connected with the steel tube upright post 22 on the long side of the support changing platform 10, the short rod 24 is connected with the steel tube upright post 22 on the short side of the support changing platform 10, and the cross rod 25 is connected with four steel tube upright posts 22 and is in an X shape. Wherein, the support changing platform 10 is removed and moved upwards after each layer of foam concrete layer 11 is backfilled.

Step three, as shown in fig. 2-3, a platform plate 20 is bolted and installed through a sealing bolt rod 19 on the top of a steel pipe upright post 22, and a horizontal jack group 15 is bolted and installed on two sides of a partition plate 16 in the middle of the platform plate 20 by utilizing a fastening bolt 17, so that a support changing platform 10 is formed;

wherein, the height of the horizontal jack set 15 is equal to the height of the center of the basement main body beam plate 5 on the floor.

Fourthly, arranging steel backing plates 9 on the foundation pit support structure 1 and the basement outer wall 6 at the equal-height positions of the horizontal jack group 15;

step five, as shown in fig. 6, placing a displacement monitoring device 4 on the basement main body beam plate 5 to monitor the displacement change of the partition plate 16, controlling the bidirectional force of the horizontal jack set 15 and propping against the steel backing plates 9 on the two sides, so that the displacement of the partition plate 16 is controlled within a set range; in fig. 7, the displacement of the partition plate 16 is controlled within a predetermined range by the same method when the other layer of the foamed concrete layer 11 is constructed.

The partition plate 16 is provided with an opening and is arranged in the middle of the platform plate 20, and the steel base plate 9 is respectively arranged on the foundation pit support structure 1 and the basement outer wall 6 at the same height as the horizontal jack group 15.

In this step, the displacement monitoring device 4 is a Total Station, i.e., a Total Station type Electronic distance meter (Electronic Total Station), which is a high-tech measuring instrument integrating light collection, mechanical collection and electrical collection, and is a surveying and mapping instrument system integrating horizontal angle, vertical angle, distance (slant distance, horizontal distance) and height difference measurement functions. Compared with the optical theodolite, the electronic theodolite changes the optical scale into the photoelectric scanning scale, and replaces manual optical micrometer reading with automatic recording and displaying reading, so that the angle measurement operation is simplified, and the generation of reading errors can be avoided. The total station is called because the instrument can be arranged once to complete all measurement work on the station. Therefore, the method is very suitable for monitoring the displacement change of the partition plate 16 in the application, and the specific operation method is the prior art, so that the detailed description thereof is omitted.

Step six, backfilling a foam concrete layer 11 in a fertilizer groove above the micro-expansion concrete belt 12 to the top of the plastic protection pipe 21;

removing the temporary support of the layer, replacing the support platform 10, the horizontal jack set 15 and the steel backing plate 9;

in this step, the concrete dismantling step is:

s1, removing the horizontal jack set 15 and the steel backing plate 9;

s2, removing the platform board 20;

s3, removing the fixed tie bar 18 on the top of the steel tube upright post 22;

s4, pulling out the steel tube upright post 22, and leaving the plastic protection tube 21.

According to the actual height, a third temporary support and a fourth temporary support can be arranged; the temporary support is a support structure in the prior art, and the structure of the temporary support is not described in detail here.

Step eight, after the foamed concrete layer 11 is constructed, pouring concrete into the plastic protection pipe 21 of the basement outer wall 6 and the basement main body beam slab 5 on the previous layer to a set height to form a second slotted hole group 13, and installing a protection pipe joint 14 at the top of the plastic protection pipe 21;

and step nine, repeating the step two to the step eight, and completing the backfilling of a plurality of foam concrete layers 11 from bottom to top until the construction of the deep foundation pit supporting and replacing support system is completed.

The construction of the foam concrete layer 11 is completed layer by layer from bottom to top, facilities such as a horizontal jack set 15 and a steel backing plate 9 are built again each time one layer is completed, the foam concrete layer 11 is backfilled after the building is completed, and the construction is repeated until the construction is completed.

In the case of the example 2, the following examples are given,

the basement is constructed by applying the construction method of the deep foundation pit supporting and support replacing system in the embodiment 1.

The present invention is not described in detail in the prior art, and therefore, the present invention is not described in detail.

It is understood that the terms "a" and "an" should be interpreted as meaning that a number of one element or element is one in one embodiment, while a number of other elements is one in another embodiment, and the terms "a" and "an" should not be interpreted as limiting the number.

Although the use of the term in the present text is used more often, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.

The present invention is not limited to the above-mentioned preferred embodiments, and any other products in various forms can be obtained by anyone in the light of the present invention, but any changes in the shape or structure thereof, which have the same or similar technical solutions as the present application, fall within the protection scope of the present invention.

Claims

1. The construction method of the deep foundation pit support changing system is characterized by comprising the following steps of:

firstly, after a foundation cushion layer (8) is constructed at the bottom of a foundation pit, pouring construction is carried out on a bottom plate (7), then a bottom outer wall (6) is poured, micro-expansion concrete is backfilled in a fertilizer groove between a foundation pit enclosure structure (1) and the bottom plate (7), a micro-expansion concrete belt (12) is formed, and a groove hole group (13) is reserved;

step two, sleeving plastic protection pipes (21) on the steel pipe stand columns (22), inserting the lower parts of the steel pipe stand columns (22) into each slotted hole of the slotted hole group (13), enabling the four steel pipe stand columns (22) to be one group, ensuring that the support changing platform (10) reaches a designed height after being installed, and bolting and installing a fixed connecting tie rod (18) at the upper part of each group of steel pipe stand columns (22);

thirdly, a platform plate (20) is bolted and installed through a sealing bolt rod (19) on the top of a steel pipe upright post (22), and horizontal jack sets (15) are bolted and installed on two sides of a partition plate (16) in the middle of the platform plate (20) through fastening bolts (17) to form a support changing platform (10);

fourthly, arranging steel backing plates (9) on the foundation pit enclosure structure (1) and the basement outer wall (6) at the equal-height positions of the horizontal jack group (15);

placing a displacement monitoring device (4) on the basement main body beam plate (5) to monitor the displacement change of the partition plate (16), controlling the bidirectional force of the horizontal jack set (15) to be exerted and propping against the steel base plates (9) on the two sides, and controlling the displacement of the partition plate (16) within a set range;

step six, backfilling a foam concrete layer (11) in a fertilizer groove above the micro-expansion concrete belt (12) to the top of a plastic protection pipe (21);

seventhly, dismantling the temporary support of the layer, replacing the support platform (10), the horizontal jack set (15) and the steel backing plate (9);

step eight, pouring concrete into the plastic protection pipe (21) to a set height to form a groove hole group (13) after a new layer of basement exterior wall (6) is constructed, and installing a protection pipe joint (14) at the top of the plastic protection pipe (21);

and step nine, repeating the step two to the step eight, and completing the backfilling of a plurality of foam concrete layers (11) from bottom to top until the construction of the deep foundation pit supporting and support changing system is completed.

2. The construction method of the deep foundation pit support and support replacing system according to claim 1, wherein in the seventh step, the concrete dismantling step is as follows:

s1, removing the horizontal jack set (15) and the steel backing plate (9);

s2, removing the platform board (20);

s3, removing the fixed tie rod (18) at the top of the steel tube upright post (22);

s4, pulling out the steel tube upright post (22) and leaving the plastic protection tube (21).

3. The construction method of the deep foundation pit support changing system according to claim 1, wherein in the fifth step, the displacement monitoring equipment (4) is a total station.

4. The construction method of the deep foundation pit support and change system according to claim 1, wherein in the second step, a plurality of connecting lug plates (27) are arranged at the upper part of the steel pipe column (22), and the steel pipe column (22) and the fixed connecting rod (18) are tightly connected through the connecting lug plates (27) and the connecting bolts (26).

5. The construction method of the deep foundation pit support and bracing system according to claim 4, wherein the fixed connecting rod (18) comprises a long rod (23), a short rod (24) and a cross rod (25), the long rod (23) is connected with the steel pipe column (22) on the long side of the support changing platform (10), the short rod (24) is connected with the steel pipe column (22) on the short side of the support changing platform (10), and the cross rod (25) is connected with four steel pipe columns (22) and is in an X shape.

6. The construction method of the deep foundation pit supporting and replacing system as claimed in claim 1, wherein the height of the horizontal jack sets (15) is equal to the center of the basement main body beam plate (5) on the floor.

7. The construction method of the deep foundation pit support replacing and supporting system according to claim 1, wherein the slotted hole group (13) of each layer of the foam concrete layer is formed by taking four slotted holes as one group and arranging a plurality of groups at even intervals.

8. The construction method of the deep foundation pit supporting and bracing system according to any one of claims 1-7, wherein in the first step, micro-expansive concrete is backfilled in a fertilizer tank between the foundation pit enclosure (1) and the bottom plate (7) to half height or nearly half height of the outer wall (6) of the basement at the bottom layer.

9. The construction method of the deep foundation pit support and bracing system according to any one of claims 1-7, wherein the temporary supports comprise a first temporary support (3) and a second temporary support (2).