CN110777800A

CN110777800A - Construction method for dismantling foundation pit concrete purlin

Info

Publication number: CN110777800A
Application number: CN201911063672.6A
Authority: CN
Inventors: 刘建; 乔国强; 王栋
Original assignee: China Railway 12th Bureau Group Co Ltd; Second Engineering Co Ltd of China Railway 12th Bureau Group Co Ltd
Current assignee: China Railway 12th Bureau Group Co Ltd; Second Engineering Co Ltd of China Railway 12th Bureau Group Co Ltd
Priority date: 2019-11-04
Filing date: 2019-11-04
Publication date: 2020-02-11

Abstract

The invention relates to the technical field of foundation pit construction, in particular to a foundation pit concrete purlin dismantling construction method. When the concrete enclosing purlin is constructed, PVC pipes are vertically bound at the position, close to the enclosing structure, of the concrete enclosing purlin to serve as rope penetrating holes of a cutting machine for positioning and segmenting, and then U-shaped ribs are pre-embedded to serve as hanging points. After the construction of the main body structure is finished, a scaffold is erected at the bottom of the concrete purlin to serve as a supporting system, expansion bolts are arranged at proper positions on the concrete purlin to fix a cutting machine, and cutting ropes are connected after penetrating through PVC pipes. And starting a cutting machine to cut off the concrete purlin in sections, and lifting the concrete purlin out in sections through the U-shaped ribs, so that the concrete purlin is finally dismantled. The method has the advantages of short construction period, high construction safety, no environmental pollution and the like, and has good popularization prospect and wide application range. The invention is mainly applied to the aspect of dismantling the concrete purlin.

Description

Construction method for dismantling foundation pit concrete purlin

Technical Field

The invention relates to the technical field of foundation pit construction, in particular to a foundation pit concrete purlin dismantling construction method.

Background

In a foundation pit supporting system, the rigidity of the enclosing purlin has a great influence on the rigidity of the whole supporting structure, and in order to ensure the overall stability of the enclosure structure, more and more concrete enclosing purlins are used for replacing steel enclosing purlins to appear in the design and construction of the foundation pit supporting system. At present, the traditional method for breaking the concrete purlin is mechanical breaking and manual breaking, vibration, noise and dust generated by the mechanical breaking not only affect a main body structure and have large influence on the surrounding environment, but also can affect surrounding building enclosures to affect a foundation pit supporting system, and meanwhile, the machine walks on a plate to be not beneficial to protecting finished products and embedded pipes. When the concrete purlin is broken manually, the labor intensity is high, the labor amount is large, the generated dust is not easy to control, and the construction period is long due to the cleaning of later-stage residues and waste steel bars.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides the construction method for dismantling the concrete purlin, which protects the stability of the existing structure when the concrete purlin is dismantled, and has the advantages of low labor intensity, short construction period and little pollution.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a foundation pit concrete purlin dismantling construction method is characterized by comprising the following steps:

a. before the concrete is poured into the concrete purlin, the PVC pipes are firmly and vertically tied, the PVC pipes are tightly attached to the inner side of the enclosure structure, the bottom of each PVC pipe is flush with the bottom of the concrete purlin, the top of each PVC pipe is higher than the top of the concrete purlin, one PVC pipe is tied to each section of the concrete purlin, and the two ends of each PVC pipe are bound by adhesive tapes so as to prevent the PVC pipes from being blocked by reverse pouring when the concrete is poured;

b. when the concrete purlin is bound with reinforcing steel bars, U-shaped ribs are welded on the two sides of the vertical main ribs, so that the concrete purlin can be conveniently lifted in a segmented mode and inserted in a shackle, and the U-shaped ribs are arranged at intervals in the middle of the concrete purlin;

c. during the construction of a foundation pit main body, after the construction of a main body structure is finished, a support bracket is erected at the bottom of the concrete purlin by adopting a steel pipe fastener scaffold, and the top surface of the bracket is erected in a manner of clinging to the concrete purlin;

d. after the scaffold is built, installing expansion screws at proper positions, fixing a cutting machine and a guide wheel, erecting the cutting machine, penetrating the disconnected cutting rope into two adjacent preformed holes for connection, and starting a rope saw cutting machine to cut off the concrete purlin in sections;

e. when the cutting is carried out, a truck crane is arranged to enter the site, the hoisting buckles are clamped into the U-shaped ribs, and the concrete purlin is lifted out in sections and loaded for outward transportation.

The PVC pipe in the step a is a PVC pipe of DN25 model.

And c, arranging one PVC pipe in the step a every 2 meters.

And c, arranging the U-shaped ribs in the step b at the middle part of the concrete purlin every 1.5 meters.

Compared with the prior art, the invention has the beneficial effects that:

the construction operation speed is fast, the noise is low, no vibration exists, the dust and waste gas pollution is small during the site construction, the cut is straight and smooth, the post-processing treatment is not needed, the convenience is provided for the treatment after the cut surface, the protection of the embedded pipe fitting of the existing structure of the bottom plate is facilitated, and the method has the advantages of low construction cost, good effect and better popularization prospect.

Drawings

FIG. 1 is a plan view of the present invention in construction;

FIG. 2 is a cross-sectional view of the construction of the present invention;

in the figure: the concrete enclosing structure comprises an enclosing structure 1, a concrete enclosing purlin 2, a PVC pipe 3, a U-shaped rib 4, a cutting machine guide wheel 5, a cutting rope 6, a scaffold 7 and a main structure 8.

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, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 and 2, a construction method for dismantling a foundation pit concrete purlin includes the following steps:

a. reserving a stringing hole, and positioning and segmenting. Before the concrete surrounding purlin 2 is poured with concrete, a binding wire is adopted to vertically bind the PVC pipe 3 tightly and tightly to the inner side of the enclosure structure 1, the bottom of the PVC pipe 3 is flush with the bottom of the concrete surrounding purlin 2, the top of the PVC pipe is 20mm higher than the top mark of the concrete surrounding purlin 2, and two ends of the PVC pipe are bound by transparent adhesive tapes to prevent the PVC pipe 3 from being blocked by reverse pouring when the concrete is poured;

b. and pre-burying U-shaped ribs 4. When the concrete purlin 2 steel bars are bound, U-shaped phi 28 round steel is welded on the two sides of the vertical main steel bars of the concrete purlin 2, the elevation of the vertical main steel bars is 100mm higher than the top surface of the concrete purlin 2, and the concrete purlin 2 can be conveniently lifted in a segmented mode and can be conveniently broken off and penetrated.

c. And (4) building a concrete surrounding purlin 2 supporting system. During the construction of the foundation pit main body, after the construction of the main body structure 8 is finished, a support bracket is erected at the bottom of the concrete purlin 2 by adopting a phi 48 multiplied by 3.0 steel pipe fastener scaffold 7, and the top surface of the bracket is erected close to the concrete purlin 2 so as to ensure the safety of the bracket in the cutting process.

d. And cutting off the concrete purlin 2. After the scaffold 7 is built, the cutting machine is erected, firstly, people are arranged to clean the cutting rope through holes to enable the cutting rope to be smooth, and expansion screws are installed at proper positions to be used for fixing the cutting machine and the cutting machine guide wheels 5. And erecting a cutting machine, penetrating the disconnected cutting rope 6 into two adjacent preformed holes, connecting, and starting the rope saw cutting machine to cut off the concrete purlin 2 in sections.

e. And hoisting the concrete enclosing purlin 2. When the cutting reaches a certain stage, a 50T truck crane is arranged to enter the field. The hoisting buckle is clamped into the U-shaped rib 4, and the concrete purlin 2 is hoisted out in sections and loaded for outward transportation.

Preferably, the PVC pipe 3 in the step a is a PVC pipe 3 of DN25 model.

Preferably, the PVC pipes 3 are arranged at intervals of 2 meters in the step a.

Preferably, the U-shaped ribs 4 in the step b are arranged at the middle part of the concrete purlin at intervals of 1.5 meters.

Although only the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art, and all changes are encompassed in the scope of the present invention.

Claims

1. A foundation pit concrete purlin dismantling construction method is characterized by comprising the following steps:

before the concrete is poured into the concrete purlin, the PVC pipes are firmly and vertically tied, the PVC pipes are tightly attached to the inner side of the enclosure structure, the bottom of each PVC pipe is flush with the bottom of the concrete purlin, the top of each PVC pipe is higher than the top of the concrete purlin, one PVC pipe is tied to each section of the concrete purlin, and the two ends of each PVC pipe are bound by adhesive tapes so as to prevent the PVC pipes from being blocked by reverse pouring when the concrete is poured;

when the concrete purlin is bound with reinforcing steel bars, U-shaped ribs are welded on the two sides of the vertical main ribs, so that the concrete purlin can be conveniently lifted in a segmented mode and inserted in a shackle, and the U-shaped ribs are arranged at intervals in the middle of the concrete purlin;

during the construction of a foundation pit main body, after the construction of a main body structure is finished, a support bracket is erected at the bottom of the concrete purlin by adopting a steel pipe fastener scaffold, and the top surface of the bracket is erected in a manner of clinging to the concrete purlin;

after the scaffold is built, installing expansion screws at proper positions, fixing a cutting machine and a guide wheel, erecting the cutting machine, penetrating the disconnected cutting rope into two adjacent preformed holes for connection, and starting a rope saw cutting machine to cut off the concrete purlin in sections;

when the cutting is carried out, a truck crane is arranged to enter the site, the hoisting buckles are clamped into the U-shaped ribs, and the concrete purlin is lifted out in sections and loaded for outward transportation.

2. The foundation pit concrete purlin dismantling construction method according to claim 1, characterized in that: the PVC pipe in the step a is a PVC pipe of DN25 model.

3. The foundation pit concrete purlin dismantling construction method according to claim 1, characterized in that: and c, arranging one PVC pipe in the step a every 2 meters.

4. The foundation pit concrete purlin dismantling construction method according to claim 1, characterized in that: and c, arranging the U-shaped ribs in the step b at the middle part of the concrete purlin every 1.5 meters.