WO2019136856A1

WO2019136856A1 - Supporting structure and construction method therefor, and superimposed pile wall doubling as supporting structure

Info

Publication number: WO2019136856A1
Application number: PCT/CN2018/081551
Authority: WO
Inventors: 魏建华; 鹿存亮; 俞海洲; 刘海新; 涂亮; 蒋馥鸿; 吴恒
Original assignee: 上海勘察设计研究院(集团)有限公司
Priority date: 2018-01-12
Filing date: 2018-04-02
Publication date: 2019-07-18
Also published as: CN108071118A

Abstract

A supporting structure, comprising a cement soil mixed wall (10) and hollow steel (17), the hollow steel (17) being disposed within the cement soil mixed wall (10); a lateral surrounding wall that blocks soil and separates water is formed outside of a foundation pit, and the hollow steel (17) is formed by means of staggered-peak welding by cutting solid steel (1) along a web plate (3) into staggered steel of the same shape. Also provided is a superimposed pile wall that doubles as a supporting structure and a construction method for a supporting structure.

Description

Supporting structure and construction method thereof and superimposed pile wall which also serves as supporting structure

Technical field

The invention relates to a novel foundation pit supporting structure and a construction method thereof, and belongs to the field of building engineering.

Background technique

The foundation pit support structure is a temporary structure, which has the characteristics of large resource consumption, high risk, long cycle and easy pollution. The foundation pit supporting structure plays the role of retaining soil and protecting the surrounding environment during the construction of the underground structure. When the main structure is out of the ground, the supporting structure loses its function, and the part that cannot be recovered or removed becomes a subterranean obstacle. With the massive development of urban underground space, how to reduce the consumption of supporting structure resources and reduce the impact on the environment has always been an important topic in the engineering field.

Common support structures include cast-in-place piles, underground continuous walls, SMW construction methods, gravity retaining walls, etc. The SMW method is introduced from Japan, and is drilled at a certain depth on the site with a multi-axis drilling and digging mixer. Spraying the cement-based strengthening agent and mixing and stirring with the foundation soil, and adopting overlapping lap joint between each construction unit, and then inserting H-shaped steel or steel plate as the stress reinforcing material before the cement-soil mixture is not hardened, to When the cement is hard, it forms a continuous, seamless, seamless underground wall with a certain strength and rigidity. However, due to the rigidity limitation of the profile steel, the SMW construction method has a weak control ability for deep and large foundation pits, which cannot meet the requirements of deep foundation pits and complex environments.

And when the main structure is out of the ground, the supporting structure loses its function, and the part that cannot be recovered or removed becomes a subsurface obstacle. The idea of a laminated wall is to use the supporting structure as part of the main structure to participate in permanent work, thereby saving engineering cost and space.

The underground continuous wall, row piles and other supporting forms have conditions to form a superimposed wall combined with the underground outdoor wall. At present, there are many examples of the combination of the underground continuous wall and the external wall to form a laminated wall, but the underground continuous wall has high cost and construction speed. Shortcomings such as slow and complicated process are generally used in deep and large foundation pit engineering with high environmental protection requirements. Due to the shortcomings of poor flatness and pollution, the bored piles are used less as a composite wall. However, steel as a supporting structure is often considered for recycling. If it is not recycled, the cost is large, so it is generally not used as a laminated wall.

Summary of the invention

In order to solve the above technical problems, the present invention provides a supporting structure, a construction method thereof and a laminated pile wall which also serves as a supporting structure, and has the advantages of large lateral rigidity, high resource utilization rate, saving construction cost, convenient construction and the like. .

The implementation of the present invention is accomplished by the following technical solutions:

A supporting structure, comprising a cement-soil mixing wall, characterized in that it further comprises a hollow-shaped steel, the hollow-shaped steel is placed in a cement-soil mixing wall, and a lateral retaining water-retaining wall is formed outside the foundation pit.

Preferably, the fast-moving steel is formed by cutting a solid steel from the web into two pieces and then snapping.

Preferably, the hollow-shaped steel is formed by welding a solid-shaped steel from the web into two pieces and then welding.

Preferably, the hollow-shaped steel is a spliced hollow-shaped steel formed by cutting a solid-shaped steel along a web into two concavo-convex steels of the same shape and then cutting by a peak.

Preferably, the hollow-shaped steel is a combined hollow-shaped steel which is cut into two halves by a solid-shaped steel along a web and then joined by a welded steel member.

Preferably, the solid profile steel is a hot rolled steel whole.

Preferably, the cement-soil mixing wall is arranged along the edge of the foundation pit, and the length of the hollow-shaped steel inserted below the bottom of the foundation pit is 0.5 to 3.0 times the depth of the foundation pit.

Preferably, a support system is further included, the support system consisting of one or several channels of cofferdams and supports and/or anchors.

Preferably, the cofferdam comprises a steel sill cofferdam, a steel cofferdam; the support and / or anchor comprises horizontal steel and / or steel truss support, oblique steel and / or steel truss support, horizontal and / or oblique Anchor rod; each support and / or anchor is cast or welded with the same road cofferdam to form the support system.

Preferably, the cement-soil mixing wall is filled with a certain amount of cement to form a certain width of cement-soil plus solid by mechanical stirring or rotary spraying; the cement-soil mixing wall is a plurality of uniaxial cement-soil mixing piles and two shafts At least one of cement soil mixing pile, triaxial cement soil mixing pile, five-axis cement soil mixing pile, jet grouting pile, and TRD.

The invention also provides a composite pile wall which also serves as a supporting structure, comprising a cement soil mixing wall and a pile side concrete surface wall, characterized in that it further comprises an open-section steel and a pile wall connecting member, and the hollow-shaped steel is placed on the cement soil mixing. Inside the wall; the pile side concrete facing wall and the hollow belly steel are connected by the pile wall connecting piece to form a base outdoor wall.

Preferably, the hollow-shaped steel is a combined hollow-shaped steel in which solid steel is cut into two halves along a web and then joined by a welded steel member.

Preferably, the solid profile steel is a hot rolled steel whole.

And a construction method of the support structure is proposed, including the following steps:

100. Construct a cement-soil mixing pile along the side of the foundation pit to form a cement-soil mixing wall, and insert the hollow-section steel in time after the cement-soil mixing pile is constructed;

Preferably, the method further comprises:

200, construction of the first support system or cantilever;

300, the first support system to be supported reaches the design strength or forms a cantilever, and the side wall of the support structure is vertically excavated to the bottom of the second support system;

400, according to the second and third steps, the second to the lowest support system or the cantilever;

500. After the foundation pit is excavated to the bottom of the pit, the underground structure of the main body shall be constructed, and the supporting structure shall be replaced in turn, and the corresponding supporting system or cantilever shall be removed;

600. After the construction of the main underground structure is completed, the gap between the outer wall of the main underground structure and the cement soil mixing wall is densely backfilled.

Preferably, the solid profile steel is a hot rolled steel whole.

The invention has the beneficial effects that: under the same steel material condition, the hollow steel is formed by reworking to improve the lateral rigidity of the steel, thereby making the supporting structure have large lateral rigidity, high resource utilization rate, and saving engineering cost; and after forming the main structure It is not necessary to dismantle the cement soil wall in the supporting structure to form a laminated pile wall, and the construction is convenient and the resource utilization rate is improved.

DRAWINGS

Figure 1 is a schematic cross-sectional view of a prior art steel;

Figure 2A is a schematic view showing the formation of a fast-formed steel;

Figure 2B is a schematic cross-sectional view of the solid-shaped steel of Figure 2A after cutting;

Figure 2C is a schematic cross-sectional view of the hollow steel of Figure 2A

Figure 3A is a schematic view of the construction support structure of the hollow belly steel of Fig. 2A

FIG. 3B is a schematic view of the stacked pile wall of the hollow belly steel of FIG. 2A;

Figure 4A is a schematic view of the formation of a fast-formed steel

Figure 4B is a schematic cross-sectional view of the solid-shaped steel in Figure 4A after cutting

Figure 4C is a schematic cross-sectional view of the hollow belly steel of Figure 4A

Figure 5A is a schematic view of the construction support structure of the hollow belly steel of Fig. 4A

Figure 5B is a schematic view of the stacked pile wall of the hollow belly steel of Figure 4A

Figure 6. Schematic diagram of the formation of a fast-formed steel

Figure 7. Flow chart of construction method of supporting structure

In the figure, 1 is solid steel; 2 is solid steel flange; 3 is solid steel web; 4 is web cutting joint; 5 is solid steel after cutting; 6 is solid steel after cutting; Plate weld; 8 is web hollow; 9 is splicing hollow steel; 10 is cement soil mixing wall; 11 is the first support system; 12 is the second support system; 13 is the third support system; 14 is the main underground structure; 15 is the bottom plate for the support; 16 is the symmetrical cutting solid steel; 17 is the combined hollow steel; 18 is the diamond steel plate; 19 is the middle floor plate support; 20 is the pile wall connection; 21 is the pile side concrete wall; Supporting cofferdam; 41 is a snap-fit structure.

The invention will be further described by way of examples with reference to the accompanying drawings.

Detailed ways

In order to solve the problems existing in the prior art, the applicant proposes a supporting structure for inserting and splicing an open-air steel in a cement soil mixing wall and a construction method thereof, as shown in FIG. 7 and referring to FIG. 2A to FIG. The construction method of the structure includes the following steps:

In the first step 100, the cement soil mixing pile is constructed along the edge line of the foundation pit to form the cement soil mixing wall 10, and the hollow soil steel is inserted in time after the cement soil mixing pile is constructed;

In the construction basement or main subterranean structure 14, a plurality of support systems or cantilevers can be formed subsequently to form a support structure layer by layer and ultimately form a basement or body subterranean structure 14. Thus, the method further includes the following steps:

In a second step 200, a first support system 11 or a cantilever (not shown) is constructed;

In the third step 300, after the first support system 11 reaches the design strength or forms a cantilever (not shown), the earthwork is vertically excavated along the side wall of the support structure to the bottom of the second support system 12;

In the fourth step 400, the second to the lower support system or the cantilever, that is, the third support system 13 is sequentially constructed according to

steps

200 and 300;

In the fifth step 500, after the foundation pit is excavated to the bottom of the pit, the underground structure 14 of the main body is constructed, and the bottom plate is sequentially changed, and the supporting structure or the cantilever (not shown) is removed after the bottom plate is changed to the design strength;

In the sixth step 600, after the construction of the main underground structure 14 is completed, the gap between the outer wall of the main underground structure 14 and the cement soil mixing wall 10 is densely backfilled.

Step 100 is explained below:

In the prior art, in step 100, directly insert the solid-shaped steel 1 (which is a steel whole material) shown in FIG. 1 , and its cross section is in an I-shape, including a structural solid-shaped steel flange 2 and a solid-shaped steel web 3; Since the transverse moment of inertia of the solid steel 1 is small, the cement soil mixing wall 10 is directly inserted into the cement soil mixing pile, and the lateral rigidity of the retaining system is small, and the resource utilization rate is low.

In order to solve the above technical problems, the applicant found in the test that by increasing the spacing of the two side Y-edges 2, a hollow-shaped steel forming a cavity structure on the solid-web type steel web 3 can increase the lateral moment of inertia of the solid-shaped steel 1 . The utilization of the fast-growing steel with improved lateral stiffness and the same specification of cement-soil mixing piles is high, and the cost is effectively saved.

The fast-formed steel used by the applicant in the present embodiment is formed by cutting the solid steel 1 from the web into a post-weld.

Preferably, the above-mentioned hollow-shaped steel is a spliced hollow-shaped steel formed by cutting the solid-shaped steel 1 into a concavo-convex shaped steel having the same shape along the web and then cutting the peak.

Referring to Figures 2A to 2C, the present embodiment will be described in detail. The applicant uses the existing solid-shaped steel 1 to form a spliced hollow-shaped steel 9, the original solid-shaped steel 1 has a length D1 of the original section, and the profile steel is cut along the web cutting seam 4. In the two halves, after the solid steel is cut, the solid 5 and 6 webs are long and h2, and the recess is h1, where h2 is greater than half of D1 and h1 is less than half of D1. After the solid-shaped steel 1 is cut, the solid-shaped

steels

5 and 6 after cutting are subjected to peak-to-peak splicing, and the splicing joint 7 is welded to form a spliced hollow-shaped steel 9, and a web hollow 8 is formed in the spliced hollow-shaped steel 9, the web The geometric edge of the hollow 8 increases the stress on the solid steel flange 2, so that the lateral stiffness of the spliced hollow profile steel 9 is greater than that of the solid profile steel 1. The length of the hollow section steel 9 is D2, which is increased by Δh compared with the section D1 of the solid section steel. That is, the cement soil mixing pile of the same specification is inserted into the spliced hollow section steel 9, and less steel is used. Therefore, the splicing of the hollow-shaped steel 9 has large lateral rigidity and high resource utilization, and can effectively save the cost. The splicing of the hollow section steel 9 section length D2 is controlled by adjusting the difference of the h2-h1 of the web cutting seam 4.

Preferably, the above-mentioned web cutting seam 4 forming the shape of the web hollow 8 in the spliced hollow profile steel 9 may take other configurations, such as a web cutting seam 4 in which ellipse and straight lines are alternately connected, and the

solid webs

5 and 6 after cutting are in respective straight lines. The upper alignment is welded to form a web hollow 8 of elliptical rim, which is more stressful to the solid web flange 2 and can save more steel.

In another embodiment, the fast-moving steel is a combined hollow-shaped steel in which solid steel 1 is cut into two halves along a web and then joined together by welded steel members.

4A to 4C, in detail, in another embodiment, the applicant uses the existing solid-shaped steel 1 to form a spliced hollow-shaped steel. The existing solid-shaped steel 1 has a length D1, and a solid-shaped steel is cut along the web. 1 cut into the same two halves, the solid belly steel 1 after cutting the solid section steel 16 section length is half of D1. The two symmetrically cut solid steels 16 are welded into a combined hollow steel 17 by using a plurality of diamond-shaped steel plates 18, and the cross-sectional length D2 of the combined hollow steel 17 is increased by Δh from the original solid steel 1 cross-section D1. The combination of the fast-moving steel 17 has a large lateral stiffness and the utilization of the same type of cement-soil mixing pile is high, which effectively saves the cost. The cross-sectional length D2 of the combined fast-moving steel 17 is controlled by adjusting the width of the diamond-shaped steel plate 18, and the hollow ratio of the web of the combined fast-form steel 17 is adjusted by the size and spacing of the diamond-shaped steel plate 18.

Referring to Fig. 6, the applicant also proposes another fast-moving steel which can realize the high utilization rate of the fast-moving steel with high lateral rigidity and the same specification of cement-soil mixing pile without the need of welding, and effectively save the cost. The applicant designs a specific web cutting seam 4 to cut a plurality of snap-shaped structures 41 of the same shape one or more times, and the two blocks of the cut-off solid steel cross-links can be firmly snapped together to form a hollow-shaped steel with lateral direction. The rigidity is high and the resource utilization rate is high, which can effectively save the cost. Of course, there are many other snap-in shapes, and the applicant will not repeat them here.

It should be noted that, in practice, the applicant also adopts a fast-formed steel which is directly industrialized and produced in one time and used in a predetermined size cement-soil mixing pile. The one-time forming hollow steel can more effectively control the stress of the web hollow to the solid steel flange, and has the same lateral stiffness and high resource utilization rate, can effectively save cost and is convenient in design and production.

Preferably, the above-mentioned solid steel 1 is the same hot rolled steel whole or steel whole material as in the prior art.

Preferably, the bottom elevation of the cement-soil mixing wall 10 is slightly lower than the height of the

hollow steel

9 or 17 to ensure the smooth insertion of the

hollow steel

9 or 17, and the length of the supporting structure below the bottom of the foundation pit is 0.5 to 3.0 times the depth of the foundation pit. .

Referring to Figures 3A and 5A, steps 200-600 are described in detail below:

After forming the cement soil mixing wall 10, the first support system 11 is constructed; the first support system 11 is composed of one or several road cofferdams and supports and/or anchors.

After the support system 11 reaches the design strength, the earthwork is vertically excavated along the side wall of the support structure to the second support system 12; the second support system 12 is composed of one or several road cofferdams and supports and/or anchors. According to the above cycle, the construction is carried out successively, after excavation to the bottom of the foundation pit, the main structure of the underground structure is constructed, and the bottom plate of the construction is changed to 15 . After the bottom plate is changed to 15 to reach the design strength, the second supporting system 12 is removed; After the mid-floor slab 19 is reached, the first supporting system 11 is removed; after the main underground structure 14 is grounded, the underground outdoor wall and the mixing wall 10 are backfilled and compacted.

Preferably, the above-mentioned cofferdam includes, but is not limited to, a steel sill cofferdam and a steel cofferdam; the support and/or anchor includes, but is not limited to, horizontal steel and/or steel truss support, oblique steel and/or steel truss support, Horizontal and / or diagonal anchors; each support and / or anchor is cast or welded with the same cofferdam to form the support system.

In another embodiment, a cantilever (not shown) is used in place of the support system described above. The cantilever (not shown) is prior art and will not be further described herein.

Preferably, the cement-soil mixing wall is filled with a certain amount of cement to form a certain width of cement soil and solid by mechanical stirring or rotary spraying; the cement-soil mixing wall is a plurality of uniaxial cement-soil mixing piles and two shafts. At least one of cement soil mixing pile, triaxial cement soil mixing pile, five-axis cement soil mixing pile, jet grouting pile, and TRD.

The supporting structure of the present invention is formed by the above construction method of the supporting structure, including the cement soil mixing wall 10, the supporting system, and the hollow steel, which is placed in the cement soil mixing wall 10 and formed outside the foundation pit. A lateral retaining water retaining wall, the support system consisting of one or several road cofferdams and supports and/or anchors.

The technical features of the supporting structure have been described in detail in the construction method, and the applicant will not repeat them here.

After the support structure is formed and the main underground structure 14 is completed, the profile steel in the cement soil mixing wall is generally recovered in the prior art. After the applicant adopts the fast-formed steel, the value of the recovered steel is limited and it is easy to cause pollution. Therefore, the applicant combines the cement-soil mixing wall 10 with the outer wall of the main underground structure 14 to form a superimposed pile wall, which can facilitate construction and improve land use. Rate and reduce construction difficulty.

Referring to Figures 3B and 5B, the superimposed pile wall which also serves as a supporting structure, including the cement-soil mixing wall 10, the pile-side concrete facing wall 21, and the hollow-section steel and pile wall connecting member 20, the hollow-shaped steel In the cement soil mixing wall 10; the pile side concrete surface wall 21 and the hollow-shaped steel are connected through the pile wall connecting member 20 to form a basement outdoor wall. The superimposed pile wall is not only a retaining structure, but also acts as a main underground, and the wall transforms and combines the existing steel to improve the mechanical properties of the steel under the unit weight condition, and participates in the permanent work together with the main structure. The application has the advantages of large lateral rigidity, cost saving, convenient construction and the like.

The above-mentioned hollow-shaped steel in the superimposed pile wall has been described in detail in the construction method, and the applicant will not repeat it here. The pile wall connector 20 will be described below.

The hollow-shaped steel is placed in the cement-soil mixing wall 10, and the support cofferdam 22 is constructed, and the pile wall connecting member 20 is mounted on the supporting coffer 22.

After the earthwork is excavated to the bottom of the pit, the cement soil adhered to the hollow steel on the inner side of the foundation pit is cut out, and the hollow soil steel cement is flattened, and the pile wall connecting member 20 is welded on the hollow steel.

The steel bars are tied on the pile side concrete surface wall 21, and the pile wall connecting member 20 is welded with the steel bars on the pile side concrete surface wall 21, and the concrete surface wall 21, the concrete surface wall 21 and the

hollow steel sections

9 and 17 and The cement-soil mixing wall 10 together form a subterranean outdoor wall.

In other embodiments, if it is necessary to recover the hollow steel, after the hollow steel is pulled out, the remaining space should be grouted in time.

The utility model has the beneficial effects that the supporting structure formed according to the construction method is used as a laminated pile wall after completing the underground main structure, and the construction method, the supporting structure and the overlapping pile wall have large lateral rigidity and high resource utilization rate. It saves the advantages of engineering cost and convenient construction.

While the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the claims of the invention Improvements and transformations, such as the specific structural form, size, quantity, etc. of each component, are not described here.

Claims

A supporting structure, comprising a cement-soil mixing wall, characterized in that it further comprises a hollow-shaped steel, the hollow-shaped steel is placed in a cement-soil mixing wall, and a lateral retaining water-retaining wall is formed outside the foundation pit.
The support structure according to claim 1, wherein said hollow profile steel is formed by cutting and/or welding of solid belly steel from the web.
The support structure according to claim 2, wherein the hollow-shaped steel is a spliced hollow-shaped steel formed by cutting a solid-shaped steel along a web into a concavo-convex steel of the same shape and then cutting by a peak.
The support structure according to claim 2, wherein the hollow-shaped steel is a combined hollow-shaped steel which is cut by a solid-shaped steel along a web and then joined by a welded steel member.
The supporting structure according to claim 1, wherein the cement-soil mixing wall is arranged along the edge of the foundation pit, and the length of the hollow-shaped steel inserted below the bottom of the foundation pit is 0.5 to 3.0 times the depth of the foundation pit.
The support structure of claim 1 further comprising a support system consisting of one or more turns and supports and/or anchors.
A superimposed pile wall which also serves as a supporting structure, comprising a cement soil mixing wall and a pile side concrete surface wall, characterized in that it also comprises an open-section steel and a pile wall connecting piece,

The hollow-shaped steel is placed in a cement soil mixing wall;

The pile side concrete facing wall and the hollow belly steel are connected by the pile wall connecting piece to form a base outdoor wall.
The composite pile wall according to claim 7, wherein the hollow section steel is formed by cutting and/or welding of solid steel from the web.
The composite pile wall according to claim 8, wherein the hollow-shaped steel is a spliced hollow-shaped steel formed by cutting a solid-shaped steel along a web into a concavo-convex shaped steel of the same shape and then cutting by a peak.
The composite pile wall according to claim 8, wherein the hollow-shaped steel is a combined hollow-shaped steel which is cut by a solid-shaped steel along a web and then joined by a welded steel member.
The composite pile wall according to claim 7, wherein the cement-soil mixing wall is arranged along the side of the foundation pit, and the length of the hollow-shaped steel inserted below the bottom of the foundation pit is 0.5 to 3.0 times the depth of the foundation pit.
A construction method of a support structure includes the following steps:

100. Construct a cement-soil mixing pile along the side of the foundation pit to form a cement-soil mixing wall, and insert the hollow-section steel in time after the cement-soil mixing pile is constructed;
The construction method according to claim 12, further comprising the steps of

200, construction of the first support system or cantilever;

300, after the first support system reaches the design strength or forms a cantilever, the side wall of the support structure is vertically excavated to the bottom of the second support system;

400, according to the second and third steps, the second to the last support system or the cantilever;

500. After the foundation pit is excavated to the bottom of the pit, the underground structure of the main body shall be constructed, and the supporting structure shall be replaced in turn, and the corresponding supporting system or cantilever shall be removed;

600. After the construction of the main underground structure is completed, the gap between the outer wall of the main underground structure and the cement soil mixing wall is densely backfilled.
The construction method according to claim 12, wherein the fast-moving steel is formed by cutting and/or welding of solid steel from the web after cutting.
The construction method according to claim 14, wherein the hollow-shaped steel is a spliced hollow-shaped steel formed by cutting a solid-shaped steel along a web into a concavo-convex shaped steel having the same shape and then cutting by a peak.
The construction method according to claim 14, wherein the hollow-shaped steel is a combined hollow-shaped steel which is cut by a solid-shaped steel along a web and then joined by a welded steel member.
The construction method according to claim 12, wherein the cement-soil mixing wall is arranged along the edge of the foundation pit, and the length of the hollow-shaped steel inserted below the bottom of the foundation pit is 0.5 to 3.0 times the depth of the foundation pit.