CN110761296A

CN110761296A - Cement-soil enclosure wall-cast-in-place pile cantilever type combined support and construction method thereof

Info

Publication number: CN110761296A
Application number: CN201911054893.7A
Authority: CN
Inventors: 卢辰; 许大鹏; 郑建建; 何剑平; 王国渝
Original assignee: Shanghai Water Design Engineering Co Ltd
Current assignee: Shanghai Water Design Engineering Co Ltd
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2020-02-07

Abstract

The invention discloses a cantilever type combined support of a cement-soil enclosure wall and a cast-in-place pile, which comprises a cement-soil mixing pile enclosure wall and is characterized in that a bored cast-in-place pile is sleeved on the outer side of the cement-soil mixing pile enclosure wall to form a combined support; the combined supporting roof is provided with a concrete pressure roof plate, so that the integrity of the enclosure structure is improved; and (3) carrying out pit bottom reinforcement on the pit bottom of the side group in the enclosure wall of the cement-soil mixing pile, increasing the stability of the enclosure structure and controlling the bulging deformation of the top and the bottom. The invention can be used for the conditions that the construction condition of the enclosure structure is limited or a building needs to be protected outside the pit, can effectively increase the rigidity of the enclosure structure under the condition that the width of the enclosure structure is not increased, reduces the lateral displacement of the enclosure structure and the surface settlement outside the pit, reduces the influence on the surrounding environment caused by excavation of the foundation pit, reduces the construction period of the project, and has good applicability and social benefit.

Description

Cement-soil enclosure wall-cast-in-place pile cantilever type combined support and construction method thereof

Technical Field

The invention relates to the field of geotechnical engineering, in particular to a cantilever type combined support of a cement soil enclosure wall-cast-in-place pile and a construction method thereof.

Background

When a building is newly constructed in an urban area, a large amount of foundation pit supporting engineering is needed, the construction conditions are often limited, and the construction conditions are mainly represented by the following three aspects: (1) the general overall arrangement in current situation urban area is regular, the space is compact, underground pipe network is complicated and complicated, and the construction space often can receive the restriction of peripheral structure (building) and pipeline, and the foundation ditch does not generally possess the slope excavation condition. (2) The normal operation of the peripheral pipelines and the structures (buildings) is ensured during the new construction, and the displacement of the peripheral structures (buildings) and underground pipelines is strictly controlled during the construction process. (3) The project close to the surrounding residential area needs to avoid long-time construction, and the construction period needs to avoid great influence on the surrounding environment. Due to the limitations of the above aspects, the design and construction of new building foundation pit supports have great challenges, and the design of foundation pit supports under soft soil geological conditions is more difficult.

Disclosure of Invention

The invention aims to provide a cantilever type combined support of a cement-soil enclosure wall-cast-in-place pile, which is used for the condition that the construction condition of an enclosure structure is limited or a structure (building) needs to be protected outside a pit, can effectively increase the rigidity of the enclosure structure under the condition that the width of the enclosure structure is not increased, reduces the lateral displacement of the enclosure structure and the surface settlement outside the pit, reduces the influence on the surrounding environment caused by excavation of a foundation pit, reduces the construction period of engineering and overcomes the defects of the traditional support mode.

In order to achieve the above object, the measures of the invention are: a cement-soil enclosure wall-cast-in-place pile cantilever type combined support comprises a cement-soil mixing pile enclosure wall and is characterized in that a bored cast-in-place pile is sleeved on the outer side of the cement-soil mixing pile enclosure wall to form a combined support; the combined supporting roof is provided with a concrete pressure roof plate, so that the integrity of the enclosure structure is improved; and (3) carrying out pit bottom reinforcement on the pit bottom of the side group in the enclosure wall of the cement-soil mixing pile, increasing the stability of the enclosure structure and controlling the bulging deformation of the top and the bottom.

Furthermore, a steel pipe and a dowel bar are inserted into the enclosure wall of the cement mixing pile, the steel pipe is inserted to be 1-2 m below the bottom of the foundation pit, the length of the dowel bar is 1-2 m, and the bending strength of the enclosure wall of the cement mixing pile is increased.

Furthermore, steel bars of the cast-in-place pile, steel dowels in the enclosure wall of the cement mixing pile and steel pipes are anchored into the concrete coping.

Furthermore, the combined support can be used for foundation pit engineering with excavation depth of 3-7 m and is determined according to the burial depth requirement of a building to be constructed.

Further, the construction method of the cantilever type combined support of the cement-soil enclosure wall-cast-in-place pile is characterized by comprising the following steps of:

A. firstly, constructing a cement-soil mixing pile enclosure wall, then sleeving a cast-in-situ bored pile on the outer side, forming a whole by utilizing the bonding force between the cement-soil mixing pile and the cast-in-situ bored pile, jointly deforming, and cooperatively stressing to form a combined support;

B. inserting steel pipes and steel bars into the enclosure wall of the cement-soil mixing pile to increase the strength of the enclosure wall of the cement-soil mixing pile;

C. the combined supporting roof is provided with a concrete coping plate, and cast-in-place pile steel bars, dowel bars and steel pipes in the enclosure wall of the cement mixing pile are anchored into the coping plate, so that the integrity of the enclosure structure is improved;

D. and (3) pit bottom reinforcement within a certain range is constructed at the bottom of the foundation pit, so that the stability of the enclosure structure is improved, and the top and bottom bulging deformation is controlled.

In the combined support, the cast-in-place pile is positioned in a tension area outside the enclosure structure and mainly bears tension, and the cement soil mainly bears pressure, so that the stress performance of the enclosure structure can be improved and the rigidity of the enclosure structure can be increased after the combined support is formed. The combined supporting form is a cantilever structure, an inner support does not need to be arranged during excavation, and the construction period can be effectively shortened. The invention can be used for the conditions that the construction condition of the enclosure structure is limited or a building needs to be protected outside the pit, can effectively increase the rigidity of the enclosure structure under the condition that the width of the enclosure structure is not increased, reduces the lateral displacement of the enclosure structure and the surface settlement outside the pit, reduces the influence on the surrounding environment caused by excavation of the foundation pit, reduces the construction period of the project, and has good applicability and social benefit.

Drawings

Fig. 1 is a structural front view of the present invention.

Fig. 2 is a horizontal sectional view of fig. 1.

In the figure: 1-cement soil enclosure wall, 2-bored pile, 3-concrete roof, 4-steel pipe, 5-steel bar, 6-pit bottom reinforcement and 7-building (building) planning.

Detailed Description

The invention provides a cement-soil enclosure wall-cast-in-place pile cantilever type combined support which is further described in detail with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

Referring to fig. 1-2, the embodiment discloses a cement-soil enclosure-cast-in-place pile cantilever type combined support, which includes a cement-soil enclosure 1, a bored cast-in-place pile 2 is sleeved outside the cement-soil enclosure 1 to form a combined support, a concrete pressure top plate 3 is arranged on the combined support top to increase the integrity of an enclosure structure, a steel pipe 4 and a steel bar 5 are inserted into the cement-soil enclosure to increase the strength of the cement-soil wall, a pit bottom reinforcement 6 is used for constructing the bottom of a foundation pit to increase the stability of the enclosure structure, and the whole combined support is implemented for realizing a planned construction (building) structure 7.

Optionally, the cast-in-place pile 2 is located in a tension area outside the enclosure structure and mainly bears tension, the cement soil 1 mainly bears pressure, and after the combined support is formed, the stress performance of the enclosure structure can be improved, and the rigidity of the enclosure structure is increased.

Optionally, a steel pipe 4 and a steel bar 5 are inserted into the cement soil enclosure wall, the steel pipe 4 is inserted 1-2 m below the bottom of the foundation pit, the steel bar 5 is 1-2 m long, and the bending strength of the cement soil wall 1 is increased.

Optionally, the combined supporting roof is provided with a concrete coping plate 3, and the steel bars of the cast-in-place pile 2, the dowel bars 5 of the cement mixing pile 1 and the steel pipes 4 are anchored into the coping plate 3, so that the integrity of the enclosure structure is improved.

Optionally, the combined supporting form is a cantilever structure, an inner support does not need to be arranged during excavation, and the construction period can be effectively shortened.

Optionally, pit bottom reinforcement 6 in a certain range is constructed at the bottom of the foundation pit, so that the stability of the building enclosure is improved, and the deformation of the top bottom bulge is controlled.

In conclusion, the invention provides the cantilever type combined support of the cement-soil enclosure wall and the cast-in-place pile, which can be used for the conditions that the construction condition of the enclosure structure is limited or a building (building) needs to be protected outside a pit, can effectively increase the rigidity of the enclosure structure under the condition that the width of the enclosure structure is not increased, reduce the lateral displacement of the enclosure structure and the surface settlement outside the pit, reduce the influence on the surrounding environment caused by excavation of the foundation pit, reduce the construction period of the project and have good applicability and social benefit.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims

1. A cement-soil enclosure wall-cast-in-place pile cantilever type combined support comprises a cement-soil mixing pile enclosure wall and is characterized in that a bored cast-in-place pile is sleeved on the outer side of the cement-soil mixing pile enclosure wall to form a combined support; the combined supporting roof is provided with a concrete pressure roof plate, so that the integrity of the enclosure structure is improved; and (3) carrying out pit bottom reinforcement on the pit bottom of the side group in the enclosure wall of the cement-soil mixing pile, increasing the stability of the enclosure structure and controlling the bulging deformation of the top and the bottom.

2. The cement-soil enclosure wall-cast-in-place pile cantilever type combined support as claimed in claim 1, wherein a steel pipe and a dowel bar are inserted into the cement-soil mixing pile enclosure wall, the steel pipe is inserted 1-2 m below the bottom of a foundation pit, the length of the dowel bar is 1-2 m, and the bending strength of the cement-soil mixing pile enclosure wall is increased.

3. The cantilever type combination support of cement-soil enclosure wall-cast-in-place pile of claim 2, wherein the cast-in-place pile reinforcing bars, the dowel bars and the steel pipes in the cement-soil mixing pile enclosure wall are anchored into the concrete coping.

4. The cantilever type combined support for the cement-soil enclosure wall-cast-in-place pile as claimed in claim 1, wherein the combined support is used for foundation pit engineering with excavation depth of 3-7 m.

5. A construction method of a cantilever type combined support of a cement-soil enclosure wall-filling pile is characterized by comprising the following steps:

6. The construction method according to claim 1, wherein in the step B, the steel pipe is inserted 1-2 m below the bottom of the foundation pit, and the dowel bar is 1-2 m long.