CN101408025B - Construction method of foundation pit using main structure as supporting point - Google Patents

Abstract

The invention discloses a foundation pit construction method which utilizes a main structure as a supporting point, and is characterized in that: the foundation pit is divided into a plurality of areas, and area division is carried out according to the requirement of construction period: 1) to the area with loose construction period requirement and large excavating depth and earth volume, the construction is carried out by adopting a central island construction method, i.e., the area is divided into a central island and a peripheral area, sequential construction is carried out to the central island, and the sequential construction is carried out to the peripheral area by utilizing the main structure as the supporting point; and 2) to the area with short construction period and having the capacity for sequential construction, a comprehensive construction method is adopted to carry out construction, i.e., the area is divided into an anchor pulling system area and a core cylinder area, the sequential construction is adopted to the anchor pulling system area, and local contrary construction is adopted to the area with insufficient position in the core cylinder area. The invention adopts the area-dividing comprehensive construction method, which avoids the problem existing in the current construction method that the excavation period is long, and shortens the construction period of the project; and the method has the beneficial effects of improving the construction speed and lowering the integral construction cost of the foundation pit.

Description

Construction method of foundation pit using main structure as support point

technical field

The invention relates to an engineering construction method, in particular to a foundation pit construction method using a main structure as a supporting point. It belongs to the field of soil engineering construction. the

Background technique

With the development of society and economy, the scale and depth of urban underground space development are increasing, and the design and construction of deep and large foundation pit projects are affected by regional geological structure, site engineering geology and hydrogeological conditions, and the surrounding environment. In the prior art, most deep and large foundation pit projects adopt a single support structure and a construction method in which the middle is straight and the side is reversed. This method has the following disadvantages: (1) due to the use of a single support structure, the safety factor of the construction is low; (2) the excavation of the foundation pit adopts the method of moving forward and backward, which leads to a longer excavation period, which affects the project on the one hand. On the other hand, it increases the overall cost of the foundation pit; (3) it can no longer meet the complex environmental requirements. the

Contents of the invention

The purpose of the present invention is to provide a foundation pit construction method using the main structure as a support point in order to overcome the shortcomings of long construction period and low safety factor in the existing foundation pit engineering construction. the

The purpose of the present invention can be achieved by taking the following technical solutions:

The foundation pit construction method using the main structure as the support point is characterized in that: the foundation pit is divided into several areas, and the divisions are carried out according to the requirements of the construction period:

1) For areas with less strict construction period requirements, large excavation depth and large earthwork, the central island construction method is used for construction, that is, the area is divided into central island and surrounding areas, and the central island is constructed in a sequential manner, and the main structure of the central island is used as the Support point, carry out construction in the surrounding area;

2) For areas with tight construction schedules and conditions for smooth operation, the comprehensive construction method is used for construction, that is, the area is divided into the anchor-tension system area and the core tube area. The area adopts partial reverse construction. the

The purpose of the present invention can also be achieved by taking the following technical solutions:

The present invention makes a further improvement: when adopting the center island construction method for construction, when constructing the surrounding area, adopt the supporting method of the enclosure structure and the main structure. the

Compared with the prior art, the present invention has the following advantages:

The present invention adopts divisional construction and the construction method of smooth side and straight side, avoiding the problem of long excavation period in the construction method of straight side and reverse side in the prior art, so that the construction period of the main body of the foundation pit is no longer limited, and the construction period of the project is shortened; At the same time, due to the overall construction method of smooth in the middle and smooth in the side, reverse construction is used in local areas subject to conditions, combined with a variety of construction methods, thereby reducing the overall cost of the foundation pit. In addition, the present invention adopts the support method of the enclosure structure and the main structure, which solves the problem that deep and large foundation pits (more than 300m in length) cannot be supported by internal supports, thereby improving the safety factor of foundation pit construction. the

Description of drawings

Fig. 1 is a schematic diagram of a specific construction method of the present invention. the

Detailed ways

Specific embodiment 1

As shown in Figure 1, a construction method of the present invention is as follows: Divide the foundation pit into several areas, and divide them according to the requirements of the construction period: for areas where the construction period is not strict, the excavation depth and the amount of earthwork are large, the center island is used for construction The method is used for construction, that is, the area is divided into the central island 1 and the peripheral area 2, and the central island 1 is constructed in a sequential manner, and the main structure of the central island is used as a support point to carry out the sequential construction in the peripheral area 2; the specific process is as follows:

First of all, the entire foundation pit is divided into several areas according to the geological requirements of the foundation pit and the requirements of the project construction period. Then, construct the underground continuous wall along the basement line of the building, as the outer wall of the basement and the enclosure structure of the foundation pit, and at the same time pour or lay down temporary supporting columns and column piles at relevant positions inside the building. Generally, the column piles should be used as much as possible Engineering piles need to be added when the engineering piles cannot be used. Next, basin excavation is adopted for the center island area, and the bottom of the foundation pit is dug to the bottom of the foundation pit, and then the bottom plate of the center island is poured. After the construction of the bottom plate of the central island is completed, the middle plate and the structural roof of the construction structure shall be constructed sequentially from bottom to top. Finally, for the surrounding construction, layered excavation is adopted from top to bottom, and temporary horizontal support beams are set in sequence, so that one end of the horizontal support beam is supported on the middle plate and top plate of the central island, and the other end is supported on the enclosure structure , forming a support system in which the surrounding enclosure structure and the main structure of the central island are supported by temporary horizontal support beams. After excavating to the bottom of the foundation pit, the base plate, middle plate and roof of the construction surrounding area shall be constructed from bottom to top, and the temporary horizontal support system shall be removed from bottom to top in order to complete the construction of the surrounding area. the

Since the support of the surrounding area of the foundation pit adopts a temporary support system, multiple excavation openings can be provided. When excavating the soil layer of the surrounding foundation pit, the earthwork can be directly transported away from the surrounding excavation openings, avoiding the need to transport the earthwork to one or more designated excavation openings during reverse construction, and then exit through the main roof of the central island Shipping problem. At the same time, the exit of the surrounding area does not need to pass through the central island area, so the further construction of the central island is no longer affected by the surrounding area, thereby shortening the construction period of the project. the

Specific embodiment 2

On the basis of Embodiment 1, this embodiment is slightly improved: For areas with tight construction schedules and conditions for continuous construction, the area of anchor-tension system adopts sequential construction, and the area 3 where the position of the core tube is insufficient uses partial reverse construction. The "anchor pull" involved in the anchor pull system area is a conventional anchor pull technique. the

Specific embodiment 3

On the basis of Embodiment 2, this embodiment is further improved: when the center island construction method is used for construction, when the surrounding area 2 is constructed, the support method of the enclosure structure and the main structure is adopted. When constructing the central island, the main structure consisting of the base plate, middle plate, top plate and supporting columns between the three will be constructed from bottom to top in the central island area. When carrying out construction on the surrounding area, use the underground continuous wall as its enclosure structure, and excavate earthwork from top to bottom. When the earthwork is excavated to the height of the surrounding roof, a temporary horizontal support beam is set up so that one end of the horizontal support beam is supported on the middle plate of the central island, and the other end is supported on the enclosure structure, forming the peripheral enclosure structure and the main body of the central island. The structure is supported by temporary horizontal support beams. When excavating to the mid-slab and floor, set the same temporary horizontal support beams. The support mode of the enclosure structure established by the above method and the main structure can improve the construction safety of the surrounding area.

Claims (2)

1. The foundation pit construction method using the main structure as a support point is characterized in that: the foundation pit is divided into several areas, which are divided according to the requirements of the construction period: 1) For areas with loose construction period requirements, large excavation depth and large earthwork volume, the central island construction method is used for construction, that is, the area is divided into central island (1) and surrounding area (2), and the central island (1) is sequentially For construction, use the main structure of the central island as a support point to carry out sequential construction on the surrounding area (2); 2) For areas with tight construction schedules and conditions for smooth operation, the comprehensive construction method is used for construction, that is, the area is divided into the anchor-tension system area and the core tube area. Area (3) adopts partial reverse construction. 2. The foundation pit construction method according to claim 1, characterized in that: when the central island construction method is used for construction, when the surrounding area (2) is constructed, the support mode of the enclosure structure and the main structure is adopted .