CN105113514B - Foundation Pit Containment System and Construction Method Using Underground Diaphragm Wall as Vertical Cantilever Fulcrum - Google Patents

Abstract

The invention discloses a foundation pit enclosure system taking an underground continuous wall as a vertical cantilever fulcrum and a construction method, wherein the underground enclosure system comprises a basement, the basement is mainly formed by correspondingly connecting the basement located in the peripheral area of a foundation pit and the basements located in other areas of the foundation pit through respective floor slabs, the basement located in the peripheral area of the foundation pit comprises the underground continuous wall, a side-shear-resistant wall and the floor slabs, the underground continuous wall is arranged along the circumference of the inner wall of the foundation pit, the underground continuous wall is the outer edge of the peripheral area of the foundation pit, the inner edge of the peripheral area of the foundation pit is the boundary line of the central area of the foundation pit and the peripheral area of the foundation pit, the side-shear-resistant wall is distributed in the peripheral area of the foundation pit, and the floor slabs are arranged on the. The lateral shear resistant wall is used as a support structure at the initial stage and is a component of a main body structure, the problem that a temporary support needs to be built and then needs to be dismantled in the construction process in the prior art is solved, the construction difficulty is simplified, the construction period is shortened, and the construction cost is reduced.

Description

Foundation Pit Containment System and Construction Method Using Underground Diaphragm Wall as Vertical Cantilever Fulcrum

technical field

The present invention relates to basement upside-down method of multi-tower high-rise super large chassis and foundation pit support technology, in particular to a foundation pit enclosure system with underground diaphragm wall as vertical cantilever fulcrum, which can be used as super large foundation pit enclosure system. Pit containment system, also relates to the construction method of the foundation pit containment system.

Background technique

The foundation pit enclosure system is a general term for the retaining structure, groundwater control, and environmental protection measures required to ensure the safety and stability of the underground space formed by excavating from the ground during the construction of the underground structure. The foundation pit engineering mainly includes the design and construction of the foundation pit enclosure system and earthwork excavation. It is a highly comprehensive system engineering, which requires not only geotechnical engineering knowledge, but also structural engineering knowledge. It involves all construction procedures such as survey, design, construction, monitoring and testing in construction projects.

In the case of poor engineering geological and hydrogeological conditions (such as deep soft soil, high groundwater level, etc.), the surrounding site space is narrow and the deformation of the surrounding environment is strict, the foundation pit enclosure system generally adopts the underground diaphragm wall as mainstream practice. Its advantages are: (1) The space within the red line of the building can be fully utilized, and the stiffness of the underground diaphragm wall is conducive to controlling the deformation of the foundation pit; (2) The underground diaphragm wall has vertical bearing capacity and anti-seepage function, and can be used as the outer wall of the basement, becoming A part of the underground structure can also be used for reverse construction to realize simultaneous construction on the ground and underground, thereby shortening the construction period; When the water-stop curtain is difficult to meet the requirements, the underground diaphragm wall can be used as the water-retaining structure to meet the requirements.

However, the method of adopting the underground diaphragm wall will cause the following problems when dealing with super-large deep foundation pits:

⑴Because the super-large deep foundation pit is very deep (usually the depth is greater than 20 meters), it is necessary to add a horizontal support system. At the same time, if the scale of the foundation pit is large, the horizontal support system needs to add temporary vertical supports (such as column piles), which will lead to There are many column piles, and more column piles will conflict with the main structure of the building, causing construction difficulties and prolonging the construction period. (2) The added vertical support and horizontal support greatly increase the project cost, and when excavating the earthwork of the foundation pit, it is difficult to excavate the foundation pit.

The upside-down method is a method of underground structure construction. Generally, the underground diaphragm wall is first constructed along the basement wall of the building or other temporary enclosure walls are constructed around the foundation pit, and at the same time, the intermediate support piles and The column is used as the vertical support to bear the self-weight and construction load of the superstructure during the construction period until the bottom is sealed, and then the beam-slab structure on the ground floor is used as the horizontal support of the underground diaphragm wall or other enclosure walls, and then excavated layer by layer Earthwork and pouring of each layer of the underground structure up to the back cover of the base plate. At the same time, since the floor structure of the ground floor has been completed, conditions have been created for the construction of the superstructure, so the construction of the above-ground structure can also be carried out layer by layer upward at the same time, so that the construction can be carried out simultaneously on the ground and below until the project is completed.

The reverse construction method has the advantages of improving the safety of underground engineering, reducing waste of resources, shortening the total construction period, and having little impact on the surrounding environment. However, its defects are: (1) Construction is carried out from top to bottom, requiring high construction accuracy and high technical difficulty. Node processing is complex; (2) The entire foundation pit system is highly systematic, requiring close cooperation between the design department and the construction department, and construction is carried out in strict accordance with the design drawings, which increases the cooperation between the design department and the construction department; (3) Since the excavation is in the The top is closed, and there are a certain number of intermediate support columns and well point pipes for dewatering in the foundation pit, so it is difficult to excavate the soil, the construction period of the earthwork will be longer than the conventional method, and the cost of the entire project is high; (4) the support position is limited by the basement If there is a basement with a large building height, due to the large basement area, it is necessary to set up temporary horizontal supports or increase the section and reinforcement of the enclosure wall; (5) The supporting piles and columns used as vertical supports are temporary supports. It needs to be dismantled during the construction of the main structure, which increases the difficulty of construction and increases the construction cost.

The usual method is to dig layer by layer to the bottom surface elevation of the basement floor during excavation of the foundation pit, and then construct layer by layer upward from the bottom plate. If the depth of the foundation pit is deep and the scale is large, it is necessary to set up lateral support systems such as support piles and beams in the middle of the foundation pit. These support systems are used as temporary supports and must be removed layer by layer during the process of construction.

To sum up, there are advantages and disadvantages in the construction of ultra-large deep foundation pit systems by adopting forward method and reverse method respectively. How to combine the two methods to maximize their advantages and avoid disadvantages is a technical problem that needs to be solved urgently in this industry.

Contents of the invention

The first object of the present invention is to provide a foundation pit containment system with underground diaphragm walls as vertical cantilever fulcrums, which can simplify construction difficulty, shorten earthwork construction period, do not need to add temporary supports, and greatly reduce construction costs.

The second object of the present invention is to provide a construction method for the above-mentioned foundation pit enclosure system with the underground diaphragm wall as the vertical cantilever fulcrum, which adopts the construction scheme of combining the reverse construction at the periphery and the sequential construction at the center, and combines the reverse construction method and the parallel construction method The advantages.

The first object of the present invention is achieved by the following technical solution: a foundation pit containment system with an underground continuous wall as a vertical cantilever fulcrum, including at least one basement, characterized in that: the basement is mainly composed of The basement in the surrounding area of the foundation pit and the basement in the rest of the foundation pit are connected through their respective floors. Construction method, the basement located in the surrounding area of the foundation pit includes an underground diaphragm wall, a lateral shear wall and a floor slab, and the underground diaphragm wall is arranged along the inner wall circumference of the foundation pit, and the underground diaphragm wall is a part of the surrounding area of the foundation pit. The outer edge, while the inner edge of the surrounding area of the foundation pit is the dividing line between the central area of the foundation pit and the surrounding area of the foundation pit, the lateral shear resistance walls are distributed in the surrounding area of the foundation pit, and the floors are layered It is installed on the lateral shear wall and the underground diaphragm wall.

In the present invention, the underground diaphragm wall + floor slab + lateral shear wall is used as the soil retaining and water-stop structure in the surrounding area of the foundation pit, so that each floor slab becomes the horizontal support of the underground diaphragm wall. At the same time, the lateral shear wall is multi-directional The force structure not only serves as the lateral fulcrum of the surrounding enclosure of the foundation pit, but also bears the vertical force of the above-ground structure. Compared with the existing upside-down method or parallel method of construction, the present invention overcomes the need to build temporary supports during construction in the prior art because the lateral shear wall can be used as a supporting structure in the initial stage and is also a component of the main structure The problem of demolition later not only greatly simplifies the construction difficulty and shortens the construction period, but also greatly reduces the construction cost because of the omission of temporary supports.

The anti-lateral shear wall of the present invention is distributed in a part of the peripheral area of the foundation pit, the part of the peripheral area of the foundation pit is called the peripheral local area of the foundation pit, and the rest of the foundation pit is the center of the foundation pit area and the remaining area around the foundation pit; or the lateral shear walls are distributed according to the circumference of the surrounding area of the foundation pit, and the remaining area of the foundation pit is the central area of the foundation pit.

The local area around the foundation pit of the present invention adopts underground continuous wall + floor slab + anti-lateral shear wall as the soil retaining and water-stop structure, which can be excavated from the rest of the foundation pit, and the rest of the area can be used as a counter-pressure soil section to resist lateral force. There is no need to set up temporary supports; or the underground diaphragm wall + floor + lateral shear wall is used as the retaining and water-stop structure along the circumference of the foundation pit, and excavation can be made from the central area, which can greatly shorten the construction period of the earthwork.

As a preferred embodiment of the present invention, the lateral shear resistance walls are close to the inner edge of the peripheral area of the foundation pit and are perpendicular to the wall surface of the corresponding underground continuous wall in the radial direction. The long side of the lateral shear wall is perpendicular to the wall surface of the underground diaphragm wall, which can withstand the lateral soil force on the underground diaphragm wall to the greatest extent, and is safer.

As an improvement of the present invention, the cross-section of the lateral shear wall is reduced layer by layer from the floor of the basement to the first floor of the main structure of the building, and the lateral shear walls above the first floor of the main structure of the building are converted into column. The principle is: the lateral shear wall above the first floor (horizontal plane of the foundation pit) of the main structure of the building only bears the vertical force, and no longer acts as a lateral fulcrum for the surrounding enclosure of the foundation pit, so its length is the shortest; while in the basement The bottom layer of the foundation pit, the lateral soil force on the side wall (underground diaphragm wall) is the largest, and the length of the lateral shear wall is also the longest. The lateral shear wall above the first floor of the main structure of the building is a column, which is not only economical, but also allows a larger space on the first floor.

As a further improvement of the present invention, the lateral shear resistant wall extends downwards into the floor cap of the basement, the floor cap is a ring beam, and the lateral shear resistant wall extends into the central hole of the ring beam, so The two walls of the lateral shear wall in the basement floor are respectively provided with lining walls, and the inner and outer sides of the lining walls are respectively provided with a row of horizontal ribs, and the inner side of each row of horizontal ribs is provided with a row of longitudinal ribs , the corresponding horizontal bars in the two rows of horizontal bars are tied by tie bars, and the steel bars of the bottom plate cap include circular horizontal bars and stirrups for hooping the horizontal bars. welding.

Both sides of the part of the anti-lateral shear wall of the present invention extending into the bottom plate cap are provided with beard tendons, and the beard tendons have a pair of protruding sections passing through the lateral shear force wall, and the protruding sections of the beard tendons Extend into the base plate cap for anchoring or weld with the plate reinforcement of the base plate cap.

In the present invention, water-swelling waterstops are wound on the wall surface of the part of the anti-lateral shear wall extending into the base plate cap and the wall surface of the anti-lateral shear wall close to the upper surface of the bottom plate cap, and the water-swelling waterstop The expansion waterstop is located inside the lining wall, which effectively prevents the seepage of groundwater.

Another object of the present invention is achieved through the following technical solutions: a construction method of the above-mentioned excavation enclosure system using the underground diaphragm wall as the vertical cantilever fulcrum, which is characterized in that it includes the following steps:

(1) Excavate the pit for setting the underground diaphragm wall to below the floor of the basement along the building red line of the foundation pit, hoist the steel cage of the underground diaphragm wall in the pit, and then pour concrete into the pit to form the underground diaphragm wall ;

(2) Excavate a number of pits for setting lateral shear walls in the surrounding area of the foundation pit to below the floor of the basement, hoist the reinforcement cages of the lateral shear walls in the pits, and then pour concrete into the pits Formation of lateral shear walls;

(3) The basement located in the surrounding area of the foundation pit is constructed by the reverse method:

① Along the inner wall of the underground diaphragm wall and the inner side of the lateral shear wall, excavate the negative floor of the basement located in the surrounding area of the foundation pit, and excavate the earthwork from the rest of the foundation pit;

② Construct the floor slab of the first floor of the main structure of the building and the floor slab of the negative floor of the basement, and at the same time, construct the above-ground structure from the floor of the first floor upwards;

③ Along the inner wall of the underground diaphragm wall and the inner side of the lateral shear wall, excavate the negative second floor of the basement located in the surrounding area of the foundation pit, excavate the earth from the rest of the foundation pit, and construct the floor slab of the second negative floor of the basement;

④Repeat step ③ until the basement located in the surrounding area of the foundation pit is completed. During the construction period, the lateral shear wall and the underground diaphragm wall supported by the floor slab that are constructed downward layer by layer make the underground diaphragm wall serve as the vertical cantilever fulcrum, and the overall Form a cantilever support structure for the surrounding soil;

⑷Construct the basement located in the remaining area of the foundation pit with the following method:

① While performing step ① in step ⑶, excavate the earthwork in the remaining areas of the foundation pit to below the floor of the basement;

②The basement located in the remaining area of the foundation pit shall be constructed in the same way. During construction, a gap shall be reserved between the basement located in the remaining area of the foundation pit and the corresponding floor slab of the completed basement located in the surrounding area of the foundation pit;

(5) Filling the reserved gap, so as to connect the basement located in the remaining area of the foundation pit and the basement located in the surrounding area of the foundation pit as a whole.

As an embodiment of the present invention, the lateral shear walls are distributed in a part of the surrounding area of the foundation pit, the part of the surrounding area of the foundation pit is called the surrounding local area of the foundation pit, and the remaining areas of the foundation pit are composed of The central area of the pit and the rest of the surrounding areas of the foundation pit. In the step (4), the construction of the basement located in the rest of the area includes the following steps:

① Excavate the earthwork in the central area of the foundation pit, and excavate it from the rest of the surrounding area of the foundation pit. The unearthed passage in the central area of ;

②Construct the basement located in the central area of the foundation pit with the same method, and at the same time excavate the earthwork in the remaining areas around the foundation pit, excavate from the remaining areas around the excavated foundation pit later, and the basement located in the central area of the foundation pit will become excavated The supporting point of the temporary horizontal support of the earthwork in the remaining area around the foundation pit;

③Construct the basement in the rest of the surrounding area of the foundation pit with the same method, and reserve a gap between the basement in the rest of the area around the foundation pit and the corresponding floor of the basement in the central area of the foundation pit;

④ Filling the reserved gaps, so as to connect the basement in the remaining areas around the foundation pit with the basement in the central area of the foundation pit as a whole.

The area of the foundation pit of the present invention is greater than or equal to 20,000 square meters, and the depth of the foundation pit is greater than or equal to 15 meters.

Compared with prior art, the present invention has following remarkable effect:

(1) The present invention adopts the underground diaphragm wall + floor slab + lateral shear wall as the soil retaining and water-stop structure in the surrounding area of the foundation pit, so that each floor slab becomes the horizontal support of the underground diaphragm wall. At the same time, the lateral shear wall is multi-directional The stressed structure not only serves as the lateral fulcrum of the surrounding enclosure of the foundation pit, but also bears the vertical force of the superstructure. It can be used as a supporting structure in the initial stage, and it is also an integral part of the main structure. Therefore, it overcomes the problem that temporary supports need to be built and then removed during construction in the prior art, which not only greatly simplifies the construction difficulty and shortens the construction period, but also saves The temporary support is removed, which greatly reduces the construction cost.

(2) The present invention adopts the underground diaphragm wall + floor slab + lateral shear wall as the soil retaining and water-stop structure in the local area around the foundation pit, which can be excavated from the rest of the foundation pit, and the rest of the foundation pit uses back pressure soil to balance the outside Earth pressure, no need to set up temporary support, or the present invention adopts underground diaphragm wall + floor slab + lateral shear wall as the retaining and water-stopping structure along the circumference of the peripheral area of the foundation pit, and can be unearthed from the central area, all of which can be significantly improved. Shorten the earthwork construction period.

(3) The cross-section of the lateral shear wall of the present invention is indented layer by layer from the floor of the basement to the first floor of the main structure of the building, and when it reaches the ground structure above the level of the foundation pit, the lateral shear wall is transformed into a column. Vertical force, the lateral shear walls above the first floor are transformed into columns, which is not only economical, but also makes the space of the first floor of the main structure of the building larger.

(4) The connection mode between the lateral shear wall and the floor cap of the basement can make the connection between the floor cap and the lateral shear wall more stable.

(5) Set up the lining wall on the wall of the lateral shear wall, and install the water-swelling water-stop strip, and the steel bar of the bottom plate cap is welded with the longitudinal reinforcement of the lateral shear wall to form a complete structure , Effectively prevent the leakage of groundwater.

(6) The present invention is applicable to situations where the area of the foundation pit is greater than or equal to 20,000 square meters, and the depth of the foundation pit is greater than or equal to 15 meters, and the advantages are more significant.

Description of drawings

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is the plan view of underground diaphragm wall and lateral shear wall distribution of embodiment 1 of foundation pit containment system of the present invention;

Fig. 2 is the vertical view of foundation pit containment system embodiment 1 in construction process of the present invention;

3 is a partial longitudinal view of Embodiment 1 of the foundation pit containment system of the present invention;

Fig. 4 is a schematic diagram of the cross-section of the lateral shear wall in Example 1 of the present invention shrinking layer by layer from bottom to top;

Fig. 5 is a schematic diagram of the connection between the lateral shear resistance wall and the basement platform of the basement according to Embodiment 1 of the present invention.

detailed description

Example 1

This embodiment is applicable to the situation that the area of the foundation pit is greater than or equal to 20,000 square meters, and the depth of the foundation pit is greater than or equal to 15 meters. As shown in Figures 1 to 3, a foundation pit enclosure system with an underground continuous wall as a vertical cantilever fulcrum includes at least one layer of basement. The basements in the rest of the area 1 are connected through their corresponding floors. Among them, the basement 31 located in the surrounding area 11 of the foundation pit is constructed by the reverse method, while the basements in the remaining areas of the foundation pit 1 are constructed by the forward method. The basement 31 of the surrounding area 11 includes an underground continuous wall 13, a lateral shear wall 14 and a floor 15, and the underground continuous wall 13 is arranged along the inner wall circumference of the foundation pit 1, that is, the underground continuous wall 13 is the part of the surrounding area 11 of the foundation pit. The outer edge, while the inner edge of the peripheral area 11 of the foundation pit is the boundary line between the central area 12 of the foundation pit 1 and the peripheral area 11 of the foundation pit 1, and the lateral shear walls 14 are distributed in the peripheral area 11 of the foundation pit 1 , in this embodiment, the lateral shear resistance walls 14 are distributed according to the circumference of the peripheral area 11 of the foundation pit, the rest of the foundation pit 1 is the central area 12 of the foundation pit 1, and the floor slabs 15 are arranged in layers to resist lateral shear forces. Wall 14 and underground continuous wall 13. The lateral shear resistance walls 14 are close to the inner edge of the peripheral area 11 of the foundation pit 1 and are perpendicular to the wall surface of the underground continuous wall 13 corresponding thereto in the radial direction. The long side of the anti-lateral shear wall 14 is perpendicular to the underground diaphragm wall 13, which can withstand the lateral soil force on the underground diaphragm wall to the greatest extent, and is safer.

As shown in Fig. 4, the cross-section of the lateral shear wall 14 shrinks layer by layer from the floor 2 of the basement to the first floor 36 of the main structure of the building, and the lateral shear walls 14 above the first floor 36 of the main structure of the building are transformed into The column is not only economical, but also can make the first floor space of the main structure of the building larger.

As shown in Figure 5, the anti-lateral shear wall 14 extends downward into the floor cap 21 of the basement layer 2 of the basement, the bottom cap 21 is a ring beam, and the anti-lateral shear wall 14 extends into the center hole of the ring beam , the two walls of the lateral shear wall 14 located in the basement floor 2 are respectively provided with lining walls 16, and the inside and outside of the lining walls 16 are respectively provided with a row of horizontal ribs 17, and the inner side of each row of horizontal ribs 17 is provided with There is a row of longitudinal ribs 18, and the corresponding horizontal ribs in the two rows of horizontal ribs 17 are tied by tie bars 19. The steel bars of the bottom plate cap 21 include circular horizontal ribs 22 and stirrups 23 for hooping the horizontal ribs, wherein the hoops The inside of the rib 23 is welded to the longitudinal rib 18 in the lining wall 16 . The two sides of the part where the lateral shear wall 14 extends into the base plate cap 21 are provided with beard tendons 24, and the beard tendons 24 have a pair of protruding sections passing through the lateral shear wall, and the protruding sections of the beard tendons 24 extend Anchoring into the base plate cap 21 or welding with the plate gluten of the base plate cap 21, the specific situation of the anchorage shown in Figure 5 of this embodiment is: due to construction errors, the protruding section of the beard tendon and the plate gluten of the base plate cap do not correspond, so they cannot be soldered together.

The water-swellable water stop belt 3 is wound on the wall surface of the part of the anti-side shear wall 14 extending into the base plate cap 21 and the wall surface of the anti-side shear wall 14 close to the upper surface of the bottom plate cap 21, and The water expansion waterstop 3 is located inside the lining wall 16 and can effectively prevent the seepage of groundwater.

A construction method of the above-mentioned foundation pit enclosure system using an underground diaphragm wall as a vertical cantilever fulcrum, specifically comprising the following steps:

(1) Excavate the pit for installing the underground diaphragm wall 13 to below the floor of the basement along the building red line of the foundation pit 1, hoist the steel cage of the underground diaphragm wall 13 in the pit, and then pour concrete into the pit to form underground diaphragm wall 13;

(2) Excavate a plurality of pits for setting the lateral shear walls 14 in the peripheral area of the foundation pit 1 to below the basement floor of the basement. Circumferential distribution of the surrounding area, the steel cage of the lateral shear wall 14 is hoisted in the pit, and then concrete is poured into the pit to form the lateral shear wall;

(3) The basement 31 located in the surrounding area of the foundation pit 1 is constructed by the reverse method:

① Along the inner wall of the underground diaphragm wall 13 and the inner side of the lateral shear wall 14, excavate the negative floor 33 of the basement located in the surrounding area of the foundation pit 1, and the earthwork is unearthed from the rest of the foundation pit 1, that is, from the foundation pit Central area 12 of 1 was unearthed;

② Construct the floor slab of the first floor of the main structure of the building and the floor slab of the negative floor of the basement, and at the same time, construct the above-ground structure from the floor of the first floor upwards;

③ Along the inner wall of the underground diaphragm wall 13 and the inner side of the lateral shear wall 14, excavate the negative second floor of the basement located in the surrounding area of the foundation pit 1. floors of floors;

④Repeat step ③ until the basement located in the surrounding area of the foundation pit 1 is completed. During the construction process, the lateral shear wall 14 and the underground diaphragm wall 13 of the floor slab supporting roof constructed downward layer by layer make the underground diaphragm wall 13 serve as a vertical wall. To the cantilever fulcrum, a cantilever support structure for the surrounding soil is formed as a whole;

(4) Construct the basement 32 located in the central area of the foundation pit 1 by following the method:

1. While carrying out 1. step in step 3, excavate the earthwork of the central area 12 of foundation pit 1 to below the basement floor of the basement;

②The basement 32 located in the central area 12 of the foundation pit 1 is constructed in the same way as shown in FIG. A gap is reserved between the basement 32 of the central area 12 of 1 and the corresponding floor slab of the completed basement 31 located in the peripheral area 11 of the foundation pit 1;

(5) Filling the reserved gap, so as to connect the basement 31 located in the peripheral area 11 of the foundation pit 1 and the basement 32 located in the central area 12 of the foundation pit 1 as a whole.

Example 2

In this embodiment, in response to the requirements of the construction party for the construction progress, one of the towers is constructed first. Therefore, the difference between this embodiment and Embodiment 1 is that the lateral shear resistance walls are distributed in the local area around the foundation pit.

The construction method of the foundation pit system of the present embodiment comprises the following steps:

(1) Excavate the pit for setting the underground diaphragm wall to below the floor of the basement along the building red line of the foundation pit, hoist the steel cage of the underground diaphragm wall in the pit, and then pour concrete into the pit to form the underground diaphragm wall ;

(2) Excavate multiple pits for setting lateral shear walls in the local area around the foundation pit to below the floor of the basement, hoist the reinforcement cages of lateral shear walls in the pits, and then place them in the pits Pour concrete to form lateral shear walls;

(3) The basement located in the local area around the foundation pit is constructed by the reverse method:

① Along the inner wall of the underground diaphragm wall and the inner side of the lateral shear wall, excavate the negative first floor of the basement located in the local area around the foundation pit, and excavate the earthwork from the remaining areas around the foundation pit;

② Construct the floor slab of the first floor of the main structure of the building and the floor slab of the negative floor of the basement, and at the same time, construct the above-ground structure from the floor of the first floor upwards;

③ Along the inner wall of the underground diaphragm wall and the inner side of the lateral shear wall, excavate the negative second floor of the basement located in a local area around the foundation pit, excavate the earth from the rest of the surrounding area, and construct the floor slab of the negative second floor of the basement;

④Repeat step ③ until the basement located in the local area around the foundation pit is completed. During the construction period, the lateral shear wall and the underground diaphragm wall supported by the floor slab that are constructed downward layer by layer make the underground diaphragm wall serve as the vertical cantilever fulcrum. A cantilever support structure for the surrounding soil is formed as a whole;

⑷Construct the basement located in the remaining area of the foundation pit with the following method:

① While performing step ① in step ⑶, excavate the earthwork in the remaining areas of the foundation pit to below the floor of the basement;

②The basement located in the remaining area of the foundation pit shall be constructed in the same manner. During construction, a gap shall be reserved between the basement located in the remaining area of the foundation pit and the corresponding floor slab of the completed basement located in the surrounding local area of the foundation pit;

(5) Fill the gap reserved in step (4), so that the basement located in the local area around the foundation pit and the basement located in the rest of the area of the foundation pit are connected as a whole.

In step (4), the basement located in the remaining area of the foundation pit is constructed using the sequential method, which specifically includes the following steps:

① Excavate the earthwork in the central area of the foundation pit, and excavate it from the rest of the surrounding area of the foundation pit. The excavation channel in the central area of the pit;

②Construct the basement located in the central area of the foundation pit with the same method, and at the same time excavate the earthwork in the remaining areas around the foundation pit. The support point of the temporary horizontal support of the earthwork in the rest of the area except the periphery of the foundation pit;

③Construct the basement located in the rest of the surrounding area of the foundation pit by following the method, and reserve a gap between the basement in the remaining area of the surrounding area of the foundation pit and the corresponding floor of the basement in the central area of the foundation pit;

④ Filling the reserved gap, so as to connect the basement located in the rest area around the foundation pit with the basement located in the central area of the foundation pit.

The embodiments of the present invention are not limited thereto. According to the above content of the present invention, according to the common technical knowledge and conventional means in this field, without departing from the above-mentioned basic technical idea of the present invention, the present invention also has other various forms of modification, Replacement or modification all fall within the protection scope of the present invention.

Claims (9)

1. using diaphram wall as a foundation pit system for vertical cantilever fulcrum, including at least one of which underground Room, it is characterised in that: described basement is mainly by being positioned at the basement of neighboring area of foundation ditch and being positioned at foundation ditch The basement in remaining region is formed by connecting by respective floor correspondence, wherein, is positioned at the neighboring area of foundation ditch Basement uses reverse construction, and the basement being positioned at remaining region of foundation ditch uses and constructs along way, is positioned at The basement of the neighboring area of foundation ditch includes diaphram wall, anti-side shear wall and floor, described diaphram wall Inwall circumference along foundation ditch is arranged, and described diaphram wall is the outer rim of foundation ditch neighboring area, and the week of foundation ditch The inner edge of edge regions is then the demarcation line with the neighboring area of foundation ditch, the central area of foundation ditch, described anti-side shear wall Being distributed in the neighboring area of foundation ditch, the layering of described floor is located on anti-side shear wall and diaphram wall；Described The cross section of anti-side shear wall successively reduces from the first floor of the backplane level of basement to major structure of construction, is positioned at and builds The anti-side shear wall building more than the agent structure first floor is all converted into post.

Foundation pit system using diaphram wall as vertical cantilever fulcrum the most according to claim 1, Described anti-side shear wall is distributed in the local of the neighboring area of foundation ditch, and the local of the neighboring area of described foundation ditch is referred to as The periphery regional area of foundation ditch, remaining region of described foundation ditch by the periphery of the central area of foundation ditch and foundation ditch remaining Region forms；Or described anti-side shear wall is according to the circle distribution of the neighboring area of foundation ditch, its of described foundation ditch Remaining region is i.e. the central area of foundation ditch.

Foundation pit system using diaphram wall as vertical cantilever fulcrum the most according to claim 2, It is characterized in that: described anti-side shear wall near the inner edge of the neighboring area of foundation ditch and be each perpendicular to diametrically with The metope of its corresponding diaphram wall.

Foundation pit system using diaphram wall as vertical cantilever fulcrum the most according to claim 3, It is characterized in that: described anti-side shear wall extends downwardly in the base plate cushion cap of basement, described base plate cushion cap is circle Beam, described anti-side shear wall stretches in the centre bore of collar tie beam, and described anti-side shear wall is in basement floor layer Two metopes on be respectively equipped with chemise, the inner side and outer side in described chemise is respectively equipped with a row of horizontal muscle, often The inner side of row of horizontal muscle is provided with a row and indulges muscle, and horizontal bar corresponding in two row of horizontal muscle is by lacing wire drawknot, base plate The reinforcing bar of cushion cap includes horizontal bar ringwise and wales the stirrup of horizontal bar, wherein, the inner side of stirrup and chemise In vertical muscle welding.

Foundation pit system using diaphram wall as vertical cantilever fulcrum the most according to claim 4, It is characterized in that: anti-side shear wall stretches into the both sides of the part in base plate cushion cap and is provided with beard muscle, described beard muscle There is a pair the section of stretching out passing anti-side shear wall, the section of stretching out of described beard muscle stretch in base plate cushion cap anchoring or Person welds with the plate gluten of base plate cushion cap.

Foundation pit system using diaphram wall as vertical cantilever fulcrum the most according to claim 5, It is characterized in that: with anti-side shear wall the end of near on the metope of the part in anti-side shear wall stretches into base plate cushion cap All it is wound around water-swellable waterstop on the metope of plate cushion cap upper surface, and described water-swellable waterstop is positioned at chemise Inner side.

7. the foundation pit system using diaphram wall as vertical cantilever fulcrum described in a claim 1 Construction method, it is characterised in that comprise the following steps:

Property line along foundation ditch excavate for arrange the pit of diaphram wall to basement backplane level with Under, by the reinforcing bar cage hoisting of diaphram wall in pit, then concrete perfusion formation underground is continuous in pit Wall；

(2) the backplane level of multiple pits to basement for arranging anti-side shear wall is excavated in the neighboring area of foundation ditch Hereinafter, by the reinforcing bar cage hoisting of anti-side shear wall in pit, then concrete perfusion formation anti-side is cut in pit Power wall；

(3) use reverse construction to be positioned at the basement of neighboring area of foundation ditch:

1. along inwall and the inner side of anti-side shear wall of diaphram wall, excavation is positioned at the neighboring area of foundation ditch The negative one layer of basement, the earthwork is unearthed from remaining region of foundation ditch；

2. the floor of the negative one layer of the floor of the construction building agent structure first floor and basement, meanwhile, from the first floor Floor is upwards constructed superstructure；

3. along inwall and the inner side of anti-side shear wall of diaphram wall, excavation is positioned at the neighboring area of foundation ditch Negative two layers of basement, the earthwork is unearthed from remaining region of foundation ditch, the floor of negative two layers of construction basement；

4. step is repeated 3., until completing to be positioned at the basement of the neighboring area of foundation ditch, in construction period, anti-side Shear wall and the floor support top diaphram wall of successively construction downwards, make diaphram wall as vertical cantilever fulcrum, Cantilever retaining structure to the peripheral soil body is integrally formed；

(4) use the basement in remaining region being positioned at foundation ditch along way construction:

1. carry out step (3) in 1. while step, the end of the earthwork in remaining region of excavation pit to basement Below flaggy；

2. use the basement in remaining region being positioned at foundation ditch along way construction, during construction, be positioned at remaining of foundation ditch Reserve between the floor that the basement in region is corresponding with the basement of the completed neighboring area at foundation ditch Gap；

(5) fill up described reserved gap, thus will be located in the basement in remaining region of foundation ditch and be positioned at foundation ditch The basement of neighboring area connects as one.

Construction method the most according to claim 7, it is characterised in that: described anti-side shear wall is distributed in base The local of the neighboring area in hole, the local of the neighboring area of described foundation ditch is referred to as the periphery regional area of foundation ditch, institute Remaining region stating foundation ditch is made up of, in described step (4) the central area of foundation ditch and remaining region of periphery of foundation ditch In, use the basement in remaining region being positioned at foundation ditch along way construction to specifically include following steps:

1. the earthwork of the central area of excavation pit, from remaining region of the periphery of foundation ditch be unearthed, the periphery of foundation ditch its The earthwork in remaining region is as back-pressure soil section, and remaining region of the periphery of foundation ditch is as the periphery regional area of foundation ditch and base The unearthed passage of the central area in hole；

2. use the basement of central area being positioned at foundation ditch along practice construction, and simultaneously excavation pit periphery its The earthwork in remaining region, is unearthed from remaining region of periphery of the foundation ditch of rear excavation, is positioned at the ground of the central area of foundation ditch Lower room becomes the supporting-point of the interim horizontal support of remaining regional earthwork of periphery excavating foundation ditch；

3. use the basement in remaining region of periphery being positioned at foundation ditch along practice construction, be positioned at foundation ditch periphery remaining Reserving gaps between the floor that the basement in region is corresponding with the basement of the central area at foundation ditch；

4. fill up described reserved gap, thus will be located in the basement in remaining region of periphery of foundation ditch and be positioned at base The basement of the central area in hole connects as one.

Construction method the most according to claim 8, it is characterised in that: the area of foundation ditch is more than or equal to 20000 square metres, and the degree of depth of foundation ditch is more than or equal to 15 meters.