CN111535332A - Method for reinforcing instability of steel sheet pile foundation pit supporting structure in soft soil area - Google Patents
Method for reinforcing instability of steel sheet pile foundation pit supporting structure in soft soil area Download PDFInfo
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- CN111535332A CN111535332A CN202010402069.2A CN202010402069A CN111535332A CN 111535332 A CN111535332 A CN 111535332A CN 202010402069 A CN202010402069 A CN 202010402069A CN 111535332 A CN111535332 A CN 111535332A
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D15/00—Handling building or like materials for hydraulic engineering or foundations
- E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/02—Sheet piles or sheet pile bulkheads
- E02D5/03—Prefabricated parts, e.g. composite sheet piles
- E02D5/04—Prefabricated parts, e.g. composite sheet piles made of steel
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
- E02D5/46—Concrete or concrete-like piles cast in position ; Apparatus for making same making in situ by forcing bonding agents into gravel fillings or the soil
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Abstract
The invention relates to a method for reinforcing instability of a supporting structure of a steel sheet pile foundation pit in a soft soil area, which comprises the steps of stopping earth excavation in the foundation pit when the supporting steel sheet pile is unstable, and backfilling a counter-pressure body to a raised soil body at the bottom in the foundation pit corresponding to the unstable supporting steel sheet pile; carrying out earthwork unloading outside the foundation pit corresponding to the upper end part of the instability supporting steel sheet pile; driving outer side steel piles corresponding to the unstable supporting steel sheet piles on the outer sides of the unstable supporting steel sheet piles, and arranging grid type stirring piles between the supporting steel sheet piles and the outer side steel piles; an inner side surrounding purlin is installed at the upper end part of the inner side of the outer side steel pile, an outer side surrounding purlin is installed at the upper end part of the outer side of the unstable supporting steel sheet pile, and a transverse steel beam and a steel strand are installed between the outer side surrounding purlin of the unstable supporting steel sheet pile and the inner side surrounding purlin of the outer side steel pile; and a plain concrete force transmission belt connected with the bearing platform and the basement bottom plate is arranged at the position of the unstable supporting steel sheet pile at the bottom in the foundation pit. The safety and stability, simple structure, the construction is simple and convenient swift, and the construction progress is fast.
Description
Technical Field
The invention relates to a method for reinforcing instability of a steel sheet pile foundation pit supporting structure in a soft soil area.
Background
The excavation of the deep foundation pit in the soft soil area is always a sub-project with high risk, although the safety factor is continuously increased on the support design in recent years, the excavation of the foundation pit is a complicated and long construction process, and the uncontrollable factors are many, so that the dangerous situation of instability still does not occur.
The steel sheet pile is firstly applied to foundation pit support such as bridge engineering midspan pier cofferdam, municipal engineering pipeline laying, temporary ditch and trench excavation and the like as a novel building material, and the steel sheet pile serving as a support structure can be recycled and reused, is low in construction cost and high in construction speed, and has a good waterproof function. The steel sheet pile has obvious advantages as a foundation pit supporting structure, so that the steel sheet pile is widely applied to construction foundation pits in recent years, but the steel sheet pile supporting structure belongs to a flexible supporting structure, the deformation is large relative to a row pile supporting structure, and the dangerous case of instability of the steel sheet pile sometimes occurs.
At present, earth excavation construction is carried out on a foundation pit in a soft soil area after steel sheet pile supporting is finished, local steel sheet piles sometimes generate instability, the common method is to backfill the foundation pit to carry out back pressure, pull out the unstable steel sheet piles, and re-drive longer steel sheet piles than the original steel sheet piles, but good effects are not necessarily obtained, and after the steel sheet piles are re-driven, the phenomena of inclination of the steel sheet piles and uplift of the foundation pit still occur. In consideration of construction cost, construction quality, construction safety and the like, a new reinforcement method for instability of the steel sheet pile needs to be explored.
Disclosure of Invention
In view of the defects of the prior art, the invention aims to provide a method for reinforcing the instability of a steel sheet pile foundation pit supporting structure in a soft soil area.
In order to solve the technical problems, the technical scheme of the invention is as follows: a method for reinforcing instability of a steel sheet pile foundation pit supporting structure in a soft soil area comprises the following steps:
(1) when the support steel sheet pile is unstable, stopping earth excavation in the foundation pit, and backfilling a counter-pressure body to a raised soil body at the bottom in the foundation pit corresponding to the unstable support steel sheet pile;
(2) carrying out earthwork unloading outside the foundation pit corresponding to the upper end part of the instability supporting steel sheet pile;
(3) driving outer side steel piles corresponding to the unstable supporting steel sheet piles on the outer sides of the unstable supporting steel sheet piles, and arranging grid type stirring piles between the supporting steel sheet piles and the outer side steel piles;
(4) an inner side surrounding purlin is installed at the upper end part of the inner side of the outer side steel pile, an outer side surrounding purlin is installed at the upper end part of the outer side of the unstable supporting steel sheet pile, and a transverse steel beam and a steel strand are installed between the outer side surrounding purlin of the unstable supporting steel sheet pile and the inner side surrounding purlin of the outer side steel pile;
(5) and a plain concrete force transmission belt is arranged at the bottom in the foundation pit corresponding to the unstable supporting steel sheet pile, and is connected with the bearing platform and the basement bottom plate.
Preferably, the unstable supporting steel sheet pile and the corresponding outer side steel pile form a space truss structure through the surrounding purlin, the transverse steel beam and the steel strand.
Preferably, the transverse steel beams and the steel strands are installed between the outer side enclosing purlin of the unstable supporting steel sheet pile and the inner side enclosing purlin of the outer side profile steel pile in a staggered mode.
Preferably, the outer profile steel piles are driven to be arranged on the inner side of the settlement cracks of the earthwork.
Preferably, the concrete of the plain concrete force transfer belt is the same as the basement main body in the same mark number.
Compared with the prior art, the invention has the following beneficial effects: 1) the earthwork is unloaded from the upper end of the outer side of the unstable support steel sheet pile, so that the side pressure of soil body to the unstable support steel sheet pile is reduced, and the unstable support steel sheet pile can be prevented from continuing to develop; 2) the outer side of the unstability supporting steel sheet pile is additionally provided with a supporting steel sheet pile which is connected with an outer side profile steel pile through a transverse steel beam and a steel strand and is used as an external fulcrum for preventing the unstability supporting steel sheet pile from continuing to develop, the position of the inclined supporting steel sheet pile at the top is kept, and the unstability supporting steel sheet pile can be prevented from continuing to develop; 3) the plain concrete force transfer belt is used as the lower support of the unstable supporting steel sheet pile, so that the phenomenon of 'skirting' caused by further inclination of the bottom of the unstable supporting steel sheet pile is avoided, and the whole supporting structure is damaged; 4) the construction cost is reduced; 5) the construction process is simple, convenient and quick, and the construction progress is accelerated.
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
Drawings
Fig. 1 is a schematic sectional view of a destabilized supporting steel sheet pile supporting structure.
Fig. 2 is a schematic plan view of a destabilized supporting steel sheet pile supporting structure.
Fig. 3 is a schematic cross-sectional view of reinforcement of a destabilized retaining steel sheet pile retaining structure.
Fig. 4 is a schematic plane view of the reinforcement of the unstable supporting steel sheet pile supporting structure.
Detailed Description
In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.
As shown in fig. 1 to 4, a method for reinforcing instability of a steel sheet pile foundation pit supporting structure in a soft soil area includes the following steps:
(1) when the support steel sheet pile is unstable, stopping earth excavation in the foundation pit, and backfilling a counter-pressure body to a raised soil body at the bottom in the foundation pit corresponding to the unstable support steel sheet pile;
(2) carrying out earthwork unloading outside the foundation pit corresponding to the upper end part of the instability supporting steel sheet pile;
(3) driving outer side steel piles corresponding to the unstable supporting steel sheet piles on the outer sides of the unstable supporting steel sheet piles, and arranging grid type stirring piles between the supporting steel sheet piles and the outer side steel piles;
(4) an inner side surrounding purlin is installed at the upper end part of the inner side of the outer side steel pile, an outer side surrounding purlin is installed at the upper end part of the outer side of the unstable supporting steel sheet pile, and a transverse steel beam and a steel strand are installed between the outer side surrounding purlin of the unstable supporting steel sheet pile and the inner side surrounding purlin of the outer side steel pile;
(5) and a plain concrete force transmission belt is arranged at the bottom in the foundation pit corresponding to the unstable supporting steel sheet pile, and is connected with the bearing platform and the basement bottom plate.
In the embodiment of the invention, the unstable supporting steel sheet pile and the corresponding outer side profile steel pile form a space truss structure through the surrounding purlin, the transverse steel beam and the steel strand.
In the embodiment of the invention, the transverse steel beams and the steel strands are installed between the outer side enclosing purlin of the unstable supporting steel sheet pile and the inner side enclosing purlin of the outer side profile steel pile in a staggered mode.
In the embodiment of the invention, the outer profile steel pile is arranged inside the settlement crack of the earthwork.
In the embodiment of the invention, the concrete of the plain concrete force transmission belt and the basement main body are labeled by the same number.
The specific implementation process comprises the following steps: example 1:
a building developed by a certain property in a coastal region is positioned on a soft soil foundation, and a foundation pit is supported according to a supporting structure shown in figure 1 in the early stage of earth excavation of a basement, wherein the foundation pit comprises a supporting steel sheet pile 1, a slope 10 and a platform 11; after the steel sheet pile is supported, when earthwork is symmetrically excavated to a distance of about 2.0m from the bottom of a foundation pit in a layering mode, a settlement crack appears at the slope top of the foundation pit, soil at the bottom of the foundation pit is raised, the settlement crack develops continuously, and meanwhile, the supporting steel sheet pile is found to be inclined through monitoring. This emergency must be dealt with as quickly as possible or it will cause serious damage to the surrounding school and municipal mains.
Aiming at the instability problem of the support steel sheet pile 1, the invention provides a reinforcing method, which comprises the following steps:
(1) when the supporting steel sheet pile is unstable, the earth excavation in the foundation pit is immediately stopped, and a back pressure body is backfilled to a raised soil body 13 at the bottom in the pit corresponding to the unstable supporting steel sheet pile so as to prevent the supporting steel sheet pile 1 from continuously inclining. In this embodiment, the counter-pressure body is formed by backfilling silty clay in the site into the foundation pit, or by transporting nearby building bricks.
(2) And unloading earthwork (slope relief 10) corresponding to the upper end of the unstable supporting steel sheet pile outside the foundation pit. In this embodiment, the earth unloading unloads all the earth in the slope area for outward transport.
(3) And driving an outer side steel pile 2 corresponding to the unstable supporting steel sheet pile on the outer side of the unstable supporting steel sheet pile, and arranging a grid type stirring pile 6 between the supporting steel sheet pile and the outer side steel pile. In the embodiment, the row spacing between the supporting steel sheet piles and the outer side section steel piles is 3.0m, and the distance between the outer side section steel piles 2 is 600 mm; meanwhile, a grid type stirring pile 6 is arranged between the supporting steel sheet pile and the outer side steel pile, the diameter of the grid type stirring pile is 500mm, and the pile spacing is 350 mm.
(4) And an inner side surrounding purlin 4 is installed at the upper end part of the inner side of the outer side steel pile, an outer side surrounding purlin 4 is installed at the upper end part of the outer side of the inclined supporting steel sheet pile, and a transverse steel beam 3 and a steel strand 5 are alternately installed between the outer side surrounding purlin of the unstable supporting steel sheet pile and the inner side surrounding purlin of the outer side steel pile. And inward support is formed at the upper end of the unstable supporting steel sheet pile. In this embodiment, the purlin and the transverse steel beam of the unstable supporting steel sheet pile and the outer side profile steel pile are all the HW350 × 350 profile steel, the steel strand is a high-strength steel strand with a diameter of 15.2mm, and the staggered distance between the transverse steel beam and the steel strand is 1.5 m. The surrounding purlin, the supporting steel sheet pile, the outer side steel pile and the transverse steel beam are connected in a welding mode, and the steel strand, the supporting steel sheet pile and the outer side steel pile are connected through steel rope buckles. Meanwhile, in order to increase the bearing capacity under the transverse steel beam, a plain concrete cushion layer 8 with the thickness of 100mm C15 is poured under the transverse steel beam.
(5) And a plain concrete force transmission belt 7 is arranged at the bottom in the pit corresponding to the unstable supporting steel sheet pile and is connected with a bearing platform and a basement bottom plate 9. In the embodiment, after the foundation pit is excavated to the bottom of the basement cushion layer, the bearing platform construction is carried out in a jumping excavation mode, after the bearing platform construction is finished, the basement bottom plate and the plain concrete force transmission belt are constructed, the thickness of the plain concrete force transmission belt is 300mm, and the mark number is the same as the basement concrete strength; before the plain concrete force transmission belt is poured, two layers of asphalt felts are arranged on the inner side of the supporting steel sheet pile and used for pulling out the concrete and the steel sheet pile.
And after the unstable supporting steel sheet pile is solidified, earth excavation in other areas is continuously finished to the designed elevation, and construction of bearing platforms in other areas and a basement bottom plate 9 is finished.
The invention is not limited to the best embodiment, and any person can obtain other various forms of reinforcement methods for the instability of the steel sheet pile foundation pit supporting structure in the soft soil area under the teaching of the invention. All equivalent changes and modifications made according to the claims of the present invention should be covered by the present invention.
Claims (5)
1. A method for reinforcing instability of a steel sheet pile foundation pit supporting structure in a soft soil area is characterized by comprising the following steps: the reinforcing method comprises the following steps:
(1) when the support steel sheet pile is unstable, stopping earth excavation in the foundation pit, and backfilling a counter-pressure body to a raised soil body at the bottom in the foundation pit corresponding to the unstable support steel sheet pile;
(2) carrying out earthwork unloading outside the foundation pit corresponding to the upper end part of the instability supporting steel sheet pile;
(3) driving outer side steel piles corresponding to the unstable supporting steel sheet piles on the outer sides of the unstable supporting steel sheet piles, and arranging grid type stirring piles between the supporting steel sheet piles and the outer side steel piles;
(4) an inner side surrounding purlin is installed at the upper end part of the inner side of the outer side steel pile, an outer side surrounding purlin is installed at the upper end part of the outer side of the unstable supporting steel sheet pile, and a transverse steel beam and a steel strand are installed between the outer side surrounding purlin of the unstable supporting steel sheet pile and the inner side surrounding purlin of the outer side steel pile;
(5) and a plain concrete force transmission belt is arranged at the bottom in the foundation pit corresponding to the unstable supporting steel sheet pile, and is connected with the bearing platform and the basement bottom plate.
2. The method for reinforcing the instability of the steel sheet pile foundation pit supporting structure in the soft soil area according to claim 1, characterized in that: the unstable supporting steel sheet pile and the outer side steel pile corresponding to the unstable supporting steel sheet pile form a space truss structure through the surrounding purlin, the transverse steel beam and the steel strand.
3. The method for reinforcing the instability of the steel sheet pile foundation pit supporting structure in the soft soil area according to claim 1, characterized in that: and cross steel beams and steel strands are installed between the outer side surrounding purlin of the unstable supporting steel sheet pile and the inner side surrounding purlin of the outer side profile steel pile in a staggered mode.
4. The method for reinforcing the instability of the steel sheet pile foundation pit supporting structure in the soft soil area according to claim 1, characterized in that: and the outer profile steel pile is arranged on the inner side of the settlement crack of the earthwork.
5. The method for reinforcing the instability of the steel sheet pile foundation pit supporting structure in the soft soil area according to claim 1, characterized in that: the concrete of the plain concrete force transmission belt and the basement main body are labeled by the same number.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010402069.2A CN111535332A (en) | 2020-05-13 | 2020-05-13 | Method for reinforcing instability of steel sheet pile foundation pit supporting structure in soft soil area |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010402069.2A CN111535332A (en) | 2020-05-13 | 2020-05-13 | Method for reinforcing instability of steel sheet pile foundation pit supporting structure in soft soil area |
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| CN111535332A true CN111535332A (en) | 2020-08-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202010402069.2A Pending CN111535332A (en) | 2020-05-13 | 2020-05-13 | Method for reinforcing instability of steel sheet pile foundation pit supporting structure in soft soil area |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102787605A (en) * | 2012-08-07 | 2012-11-21 | 天津二十冶建设有限公司 | Method for inclining bar-type foundation pit support steel sheet pile of soft soil foundation |
| CN110158602A (en) * | 2019-06-10 | 2019-08-23 | 中交第二航务工程局有限公司 | A kind of Soft Clay deep foundation pit support excavation construction structure and construction method |
-
2020
- 2020-05-13 CN CN202010402069.2A patent/CN111535332A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102787605A (en) * | 2012-08-07 | 2012-11-21 | 天津二十冶建设有限公司 | Method for inclining bar-type foundation pit support steel sheet pile of soft soil foundation |
| CN110158602A (en) * | 2019-06-10 | 2019-08-23 | 中交第二航务工程局有限公司 | A kind of Soft Clay deep foundation pit support excavation construction structure and construction method |
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