阅读说明：本技术 适用于富水砂卵层高承压圆形深基坑结构及其施工方法 (High-pressure-bearing circular deep foundation pit structure suitable for water-rich sand-gravel layer and construction method thereof ) 是由 宋建禹 王金龙 张礼仁 吕延豪 张海涛 郑凯 游龙飞 于 2020-07-14 设计创作，主要内容包括：本发明涉及一种适用于富水砂卵层高承压圆形深基坑结构,包括圆形的基坑以及沿基坑的侧壁布设的地连墙,地连墙包括沿圆形方向依次布设的多个槽段以及浇筑于槽段中的混凝土,每一槽段卡进与其相邻的槽段的槽口中。还提供一种适用于富水砂卵层高承压圆形深基坑的施工方法,包括步骤S1-S6。本发明通过设置圆形的地连墙,充分利用了圆筒形结构的“拱效应”,使地连墙的各槽段相互挤压约束形成整体共同作用,适于开挖深度大、承压含水层厚度及埋深均极大而导致隔水帷幕难以穿透承压含水层的基坑工程,采用圆形基坑的水下开挖方式可有效提高现场施工效率、防止基底突涌的发生,能改善地连墙的受力与变形状态,保证了基坑的开挖安全,提高了基坑的开挖进度。(The invention relates to a high-pressure-bearing circular deep foundation pit structure suitable for a water-rich sand-egg layer, which comprises a circular foundation pit and a ground connecting wall arranged along the side wall of the foundation pit, wherein the ground connecting wall comprises a plurality of groove sections which are sequentially arranged along the circular direction and concrete poured in the groove sections, and each groove section is clamped into a notch of the adjacent groove section. The construction method suitable for the water-rich sand-egg layer high-pressure-bearing circular deep foundation pit comprises the steps of S1-S6. The invention makes full use of the arch effect of the cylindrical structure by arranging the circular diaphragm wall, so that all groove sections of the diaphragm wall are mutually extruded and restrained to form the integral combined action, the diaphragm wall is suitable for foundation pit engineering with large excavation depth, large thickness and burial depth of the bearing water-bearing layer and difficult penetration of a waterproof curtain through the bearing water-bearing layer, the underwater excavation mode of the circular foundation pit can effectively improve the field construction efficiency, prevent the occurrence of base inrush, improve the stress and deformation state of the diaphragm wall, ensure the excavation safety of the foundation pit and improve the excavation progress of the foundation pit.)

1. The utility model provides a be applicable to high pressure-bearing circular deep basal pit structure in rich water sand ovum layer which characterized in that: the concrete foundation comprises a circular foundation pit and a ground connection wall arranged along the side wall of the foundation pit, wherein the ground connection wall comprises a plurality of groove sections sequentially arranged along the circular direction and concrete poured in the groove sections, and each groove section is clamped into a notch of the adjacent groove section.

2. The circular deep foundation pit structure suitable for high pressure bearing of rich water sand egg layer of claim 1, characterized by: the underground continuous wall is communicated with the water-stopping dry excavation section and the underwater excavation section.

3. The circular deep foundation pit structure suitable for high pressure bearing of rich water sand egg layer of claim 2, characterized by: and reinforcing bodies are arranged on the inner side and the outer side of the underground diaphragm wall in the water-stopping dry excavation section.

4. The circular deep foundation pit structure suitable for high pressure bearing of rich water sand egg layer of claim 2, characterized by: and an extraction device and a water filtering and recharging device are arranged in the underwater excavation section.

5. The circular deep foundation pit structure suitable for high pressure bearing of rich water sand egg layer of claim 2, characterized by: the waterproof curtain is arranged on the surface of the diaphragm wall in the waterproof dry excavation section.

6. The circular deep foundation pit structure suitable for high pressure bearing of rich water sand egg layer of claim 2, characterized by: and a top crown beam is arranged on the diaphragm wall in the water-stopping dry excavation section.

7. The circular deep foundation pit structure suitable for high pressure bearing of rich water sand egg layer of claim 1, characterized by: and a multistage sedimentation tank is arranged outside the foundation pit.

8. The circular deep foundation pit structure suitable for high pressure bearing of rich water sand egg layer of claim 1, characterized by: and a dewatering well is arranged in the foundation pit.

9. The construction method suitable for the water-rich sand-egg layer high-pressure-bearing circular deep foundation pit is characterized by comprising the following steps of:

S1, before a circular foundation pit is excavated downwards, a circular diaphragm wall is constructed, and a top crown beam is constructed above the diaphragm wall;

s2, constructing a dewatering well for dewatering and dewatering, and digging a circular foundation pit downwards in an area enclosed by the circular diaphragm wall after the water level in the pit is lowered to the designed elevation;

s3, sequentially excavating in layers from top to bottom, and sequentially pouring a plurality of reinforced concrete ring beams on the side wall of the diaphragm wall at intervals along the height direction in the excavating process;

s4, pouring water into the pit after the pit is excavated to the bottom of the first-stage foundation pit and the last ring beam reaches the design strength;

s5, excavating underwater to the bottom of the second-stage foundation pit, and pouring bottom sealing concrete in a layered mode underwater;

and S6, after the capping concrete reaches the designed strength, removing slurry in the pit, carrying out segmented layering construction on the main body structure in the pit from bottom to top, and gradually dismantling the reinforced concrete ring beam.

10. The construction method of the circular deep foundation pit with high bearing capacity and the water-rich sand-egg layer as claimed in claim 9, wherein the construction method comprises the following steps: before constructing the circular diaphragm wall, the construction site is leveled, and the inner side and the outer side of the foundation pit are reinforced.

Technical Field

The invention relates to the technical field of urban rail transit construction and municipal engineering construction, in particular to a high-pressure-bearing circular deep foundation pit structure suitable for a water-rich sand-gravel layer and a construction method thereof.

Background

In the urban rail transit construction field and the municipal engineering construction field, for a large number of deep foundation pit projects influenced by confined water, the shape of a foundation pit is generally approximate to square, and technical measures such as water isolation, pressure reduction or pit bottom reinforcement and bottom sealing are adopted in foundation pit excavation. The widely adopted foundation pit shape and technical measures are applicable to foundation pit engineering with smaller excavation depth and water-proof curtain capable of completely penetrating confined aquifer. However, for deep foundation pit engineering in which a waterproof curtain is difficult to penetrate through a confined aquifer due to large excavation depth and the thickness and burial depth of the confined aquifer, and buildings (structures) sensitive to sedimentation exist within the influence range of foundation pit excavation, the square foundation pit is large in deformation and poor in self-stability after being stressed, and needs to bear huge water pressure and soil pressure in the excavation process, and the actual engineering needs are difficult to meet by adopting conventional confined water treatment measures and construction schemes. At least two reinforced concrete waist beams and corresponding reinforced concrete inner supports need to be arranged inside the square foundation pit, the reinforced concrete inner supports can seriously affect the selection of site foundation pit excavation equipment and the foundation pit excavation progress, and if the inner supports are deformed due to site construction collision, the enclosure structure is easily damaged, so that the failure of a reinforced concrete inner support system is caused, and the collapse of the whole foundation pit is caused.

Disclosure of Invention

The invention aims to provide a high-pressure-bearing circular deep foundation pit structure suitable for a water-rich sand egg layer and a construction method thereof, which can at least solve part of defects in the prior art.

In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions: the utility model provides a be applicable to circular deep basal pit structure of high pressure-bearing of rich water sand ovum layer, includes that circular foundation ditch and the ground that lays along the lateral wall of foundation ditch link the wall, the ground links the wall including a plurality of groove sections that lay in proper order along circular direction and pour in the concrete in the groove section, each the groove section card advances in the notch rather than adjacent groove section.

The underground diaphragm wall is communicated with the water-stopping dry excavation section and the underwater excavation section.

Furthermore, reinforcing bodies are arranged on the inner side and the outer side of the underground diaphragm wall in the water-stopping dry excavation section.

Furthermore, an extraction device and a water filtering and recharging device are arranged in the underwater excavation section.

Further, the waterproof curtain is arranged on the surface of the diaphragm wall in the waterproof dry excavation section.

Further, a top crown beam is arranged on the diaphragm wall in the water-stopping dry excavation section.

Furthermore, a multistage sedimentation tank is arranged outside the foundation pit.

Furthermore, a dewatering well is arranged in the foundation pit.

The embodiment of the invention provides another technical scheme: a construction method suitable for a water-rich sand-egg layer high-pressure-bearing circular deep foundation pit comprises the following steps:

s1, before a circular foundation pit is excavated downwards, a circular diaphragm wall is constructed, and a top crown beam is constructed above the diaphragm wall;

s2, constructing a dewatering well for dewatering and dewatering, and digging a circular foundation pit downwards in an area enclosed by the circular diaphragm wall after the water level in the pit is lowered to the designed elevation;

s3, sequentially excavating in layers from top to bottom, and sequentially pouring a plurality of reinforced concrete ring beams on the side wall of the diaphragm wall at intervals along the height direction in the excavating process;

s4, pouring water into the pit after the pit is excavated to the bottom of the first-stage foundation pit and the last ring beam reaches the design strength;

s5, excavating underwater to the bottom of the second-stage foundation pit, and pouring bottom sealing concrete in a layered mode underwater;

and S6, after the capping concrete reaches the designed strength, removing slurry in the pit, carrying out segmented layering construction on the main body structure in the pit from bottom to top, and gradually dismantling the reinforced concrete ring beam.

And further, before constructing the circular diaphragm wall, leveling the construction site and reinforcing the inner side and the outer side of the foundation pit.

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

1. through setting up the circular shape diaphragm wall, make full use of the "arch effect" of cylindrical structure, make each groove section of diaphragm wall extrude each other and restrain and form whole combined action, it is big to be suitable for the excavation depth, the confined aquifer thickness and buried depth are all very big and lead to the water proof curtain to be difficult to pierce through the foundation ditch engineering of confined aquifer, the excavation mode under water of adopting circular foundation ditch can effectively improve on-the-spot efficiency of construction, prevent the emergence that the basement gushes suddenly, and can improve the atress and the deformation state of diaphragm wall, the excavation safety of foundation ditch has been guaranteed, the excavation progress of foundation ditch has been improved, the excavation cost of foundation ditch has been reduced.

2. Compared with the existing square foundation pit, the square foundation pit is internally provided with at least two reinforced concrete waist beams and corresponding reinforced concrete inner supports, the round foundation pit is internally provided with the round reinforced concrete ring beam to serve as a foundation pit supporting structure, and risks existing in the square foundation pit can be avoided.

Drawings

Fig. 1 is a schematic view of a high-pressure-bearing circular deep foundation pit structure suitable for a water-rich sand-egg layer according to an embodiment of the invention;

Fig. 2 is a schematic view of a diaphragm wall suitable for a water-rich sand-egg layer high-pressure-bearing circular deep foundation pit structure provided by an embodiment of the invention;

FIG. 3 is an enlarged partial schematic view of FIG. 2;

in the reference symbols: 1-underground diaphragm wall; 10-a trough section; 2-waterproof curtain; 3-top crown beam; 4-dewatering well; 5-first level pit bottom; 6-second level pit bottom; 70-a first ring beam; 71-a second ring beam; a-ground elevation; b-outside pit water line.

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.