A method for deep foundation pit excavation by combining a mobile platform with a temporary structure

Abstract

The present invention provides a method for deep foundation pit excavation by combining a mobile platform with a temporary structure, belonging to the field of building construction. The technical solution is as follows: The excavation method includes the following steps: S1. Before excavation, dewatering wells should be dug for dewatering; S2. Install the installation frame at the end of the pile foundation steel casing, and make the distance from the lowest point of the installation frame to the top surface of the steel casing 1.25 meters; S3. Place precast steel-concrete beams with external steel on both sides of adjacent installation frames, and several adjacent steel-concrete beams with external steel form a connecting beam. Then, lay steel-concrete plates with external steel on the steel-concrete beams with external steel to form a working platform; S4. The rotary drilling rig excavates the soil around the platform on the working platform, and the working platform supports the rotary drilling rig. After the excavation of the soil around is completed, continue to assemble the platform for the rotary drilling rig to move forward. After the rotary drilling rig moves forward, remove the previous working platform. The beneficial effect of the present invention is that a mobile platform is arranged in the foundation pit, and excavation is carried out from the middle to the surrounding, greatly improving the construction efficiency.

Description

Technical Field

[0001] The present invention relates to the field of building construction, and particularly to a method for deep foundation pit excavation by combining a mobile platform with a temporary structure. Background Art

[0002] Foundation pit engineering has strong regionality. For example, in foundation pits with different engineering geological and hydrogeological conditions such as soft clay foundations and loess foundations, there are significant differences in foundation pit engineering. The design and construction of the support system for foundation pit engineering and the earth excavation should be adapted to local conditions and carried out according to local circumstances.

[0003] Foundation pit engineering is a systematic project. Foundation pit engineering mainly includes two parts: the design of the support system and the earth excavation. Whether the construction organization of the earth excavation is reasonable will play an important role in the success of the support system. Unreasonable earth excavation, steps, and speed may lead to the displacement of the main structure pile foundation, excessive deformation of the support structure, and even cause the instability of the support system and lead to damage. At the same time, during the construction process, monitoring should be strengthened to strive for information-based construction. The general principle for deep foundation pit earth excavation is "layered excavation, support first and then excavation";

[0004] The main methods for deep foundation pit earth excavation include layered earth excavation, sectional earth excavation, basin-type earth excavation, center-island type earth excavation, etc. It should be selected according to factors such as the size of the foundation pit area, excavation depth, form of the support structure, and environmental conditions. For this project, if the conventional method is used for excavation, the long-arm excavator can only excavate the earth within the field of vision of the cab, and cannot excavate the earth from the lower side. To complete the excavation completely, excavation needs to be carried out separately around the foundation pit, which is time-consuming and inconvenient for construction. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for deep foundation pit excavation by combining a mobile platform with a temporary structure, which sets a mobile platform in the foundation pit and excavates from the middle to the surrounding, greatly improving the construction efficiency.

[0006] The present invention is achieved by the following measures:

[0007] A method for deep foundation pit excavation by combining a mobile platform with a temporary structure, characterized in that the excavation method includes the following steps:

[0008] S1. Before excavation, dewatering wells should be dug for dewatering;

[0009] S2. Install the mounting frame at the end of the pile foundation steel casing, and make the distance from the lowest part of the mounting frame to the top surface of the steel casing 1.25 meters;

[0010] S3. Place precast external steel-concrete beams on both sides of the adjacent mounting frames. A number of adjacent external steel-concrete beams form a connecting beam, and then an external steel-concrete slab is laid on the external steel-concrete beams to form a working platform;

[0011] S4. The rotary drilling rig excavates the soil around the working platform on the working platform. The working platform supports the rotary drilling rig. After the excavation of the soil around is completed, continue to assemble the working platform for the rotary drilling rig to move forward, and remove the previous working platform after the rotary drilling rig moves forward.

[0012] The specific features of the present invention also include:

[0013] The steel casing is a temporary casing or a permanent casing for pile foundation construction and is pre-buried before pile foundation construction.

[0014] The mounting frame includes a mounting ring frame with a U-shaped cross-section. The mounting ring frame is arranged at the end of the steel casing, and support plates are symmetrically arranged at positions close to the bottom on both sides of the mounting ring frame;

[0015] The externally-bonded steel reinforced concrete beam is arranged on the support plates of adjacent mounting frames.

[0016] Limit columns are arranged at positions close to the ends of the support plates, and the externally-bonded steel reinforced concrete beam is arranged between the limit columns and the mounting ring frame;

[0017] Preferably, the limit columns are stud bolts, threaded holes are opened at positions close to the ends of the support plates, and the stud bolts are arranged in the threaded holes.

[0018] Preferably, the mounting frame can also be formed by welding support brackets on both sides of the pile foundation steel casing, and the externally-bonded steel reinforced concrete beam is placed on the support brackets.

[0019] The beneficial effects of the present invention are as follows: A mobile platform is arranged in the foundation pit and excavated from the middle to the periphery, greatly improving the construction efficiency;

[0020] The present invention provides a method for deep foundation pit excavation by combining a mobile platform with a temporary structure, aiming to solve the problem of inconvenient construction caused by the rotary drilling rig not being able to see the soil at the lower part of the side due to the influence of the operation vision during deep foundation pit excavation. Therefore, in order to ensure that the rotary drilling rig expands the operation vision and is convenient for single-point multi-side simultaneous construction and avoid extending the construction period, this construction plan is proposed. This plan is convenient for the rotary drilling rig to carry out excavation at a single point multiple times in the foundation pit excavation, avoiding the problem of extended construction period caused by multiple position movements of the rotary drilling rig. This plan has fast soil excavation, integrated excavation and soil removal, saves costs such as cranes and gantry crane buckets, and has high economic benefits.

[0021] Meanwhile, the present invention relates to a method for deep foundation pit excavation using a mobile platform, a casing pipe, and a rotary drilling rig, which mainly consists of a steel casing pipe, a mounting frame, and an externally clad steel-concrete slab. The main method is to build a temporary platform in the foundation pit for the rotary drilling rig to work on. The rotary drilling rig first excavates the soil around the platform. After the excavation of the soil around is completed, the platform is dismantled while excavating the soil below the platform. This solution can accelerate the excavation speed and avoid the extension of the construction period caused by the repeated mobilization of the rotary drilling rig due to vision problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of the construction use state of an embodiment of the present invention.

[0023] Figure 2 is a schematic internal structural diagram of the mounting frame in an embodiment of the present invention.

[0024] Among them, the reference numerals are: 1, pile foundation steel casing pipe; 2, mounting frame; 3, externally clad steel-concrete beam; 4, externally clad steel-concrete slab; 5, mounting ring frame; 6, support plate; 7, limit column. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] To clearly illustrate the technical features of this solution, the following is an elaboration of this solution through specific embodiments.

[0026] See Figure 1 and 2 , a method for deep foundation pit excavation by combining a mobile platform with a temporary structure, characterized in that the excavation method includes the following steps:

[0027] S1. Before excavation, dewatering wells should be dug for dewatering;

[0028] S2. Install the mounting frame 2 at the end of the pile foundation steel casing pipe 1, and make the distance from the lowest part of the mounting frame 2 to the top surface of the casing pipe 1.25 meters;

[0029] S3. Place prefabricated externally clad steel-concrete beams 3 on both sides of adjacent mounting frames 2. A number of adjacent externally clad steel-concrete beams 3 form a connecting beam, and then an externally clad steel-concrete slab 4 is laid on the externally clad steel-concrete beams 3 to form a working platform;

[0030] S4. The rotary drilling rig excavates the soil around the working platform on the working platform. The working platform supports the rotary drilling rig. After the excavation of the soil around is completed, continue to assemble the working platform for the rotary drilling rig to move forward, and dismantle the previous working platform after the rotary drilling rig moves forward.

[0031] The specific features of the present invention also include:

[0032] The steel casing pipe is a temporary or permanent casing pipe for pile foundation construction and is pre-buried before pile foundation construction.

[0033] The mounting bracket 2 includes a mounting ring bracket 5 with a U-shaped cross-section. The mounting ring bracket 5 is arranged at the end of the steel casing, and support plates 6 are symmetrically arranged near the bottom positions on both sides of the mounting ring bracket 5;

[0034] An externally-bonded steel reinforced concrete beam 3 is arranged on the support plates 6 of adjacent mounting brackets 2.

[0035] A limit post 7 is arranged near the end position of the support plate 6, and an externally-bonded steel reinforced concrete beam 3 is arranged between the limit post 7 and the mounting ring bracket 5;

[0036] Preferably, the limit post 7 is a stud, a threaded hole is opened near the end position of the support plate 6, and the stud is arranged in the threaded hole.

[0037] Preferably, the mounting bracket 2 can also be formed by welding support brackets on both sides of the pile foundation steel casing 1, and the externally-bonded steel reinforced concrete beam 3 is placed on the support brackets.

[0038] The beneficial effects of the present invention are as follows: A mobile platform is arranged in the foundation pit and excavated from the middle to the periphery, greatly improving the construction efficiency;

[0039] The present invention provides a method for deep foundation pit excavation by combining a mobile platform and a temporary structure, aiming to solve the problem of inconvenient construction caused by the inability to see the soil on the lower side of the self-side due to the influence of the operation vision during the deep foundation pit excavation by a rotary drilling rig. Therefore, in order to ensure that the rotary drilling rig can expand the operation vision and facilitate simultaneous construction on multiple sides of a single point, and avoid extending the construction period, this construction plan is proposed. This plan is convenient for the rotary drilling rig to conduct excavation at a single point multiple times during the foundation pit excavation, avoiding the problem of extended construction period caused by multiple position movements of the rotary drilling rig. This plan has fast soil excavation, integrates excavation and soil removal, saves costs such as cranes and gantry crane buckets, and has high economic benefits.

[0040] At the same time, the present invention provides a method for deep foundation pit excavation using a mobile platform, a casing, and a rotary drilling rig, which mainly consists of a steel casing, a mounting bracket 2, and an externally-bonded steel concrete slab 4. The main method is to build a temporary platform for the rotary drilling rig to work in the foundation pit, so that the rotary drilling rig first excavates the soil around the platform. After the excavation of the soil around is completed, the platform is dismantled while excavating the soil below the platform. Using this plan can speed up the soil excavation speed and avoid the problem of extended construction period caused by multiple back-and-forth movements of the rotary drilling rig due to vision problems.

[0041] The technical features not described in the present invention can be realized by or adopt the prior art, and will not be elaborated here. Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions, or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for deep foundation pit excavation by a mobile platform in combination with a temporary structure, characterized in that, The excavation method includes the following steps: S1. Before excavation, dewatering wells should be dug for dewatering; S2. Install the installation frame at the end of the pile foundation steel casing, and make the distance from the lowest part of the installation frame to the top surface of the steel casing 1.25 meters; S3. Place precast concrete beams with external steel packages on both sides of adjacent installation frames. Several adjacent concrete beams with external steel packages form a connecting beam, and then lay concrete slabs with external steel packages on the concrete beams with external steel packages to form a working platform; S4. The rotary drilling rig excavates the soil around the working platform on the working platform. The working platform supports the rotary drilling rig. After the excavation of the surrounding soil is completed, continue to assemble the working platform for the rotary drilling rig to move forward. After the rotary drilling rig moves forward, remove the previous working platform.

2. The method for deep foundation pit excavation using the mobile platform combined temporary structure according to claim 1, wherein The steel casing is a temporary casing or a permanent casing for pile foundation construction and is pre-buried before pile foundation construction.

3. The method for deep foundation pit excavation using the combined temporary structure of the mobile platform according to claim 2, characterized in that The installation frame includes an installation ring frame with a U-shaped cross-section. The installation ring frame is arranged at the end of the steel casing, and support plates are symmetrically arranged at positions close to the bottom on both sides of the installation ring frame; The concrete beams with external steel packages are arranged on the support plates of adjacent installation frames.

4. The method for deep foundation pit excavation using the combined temporary structure of the mobile platform according to claim 3, characterized in that Limit columns are arranged at positions close to the ends of the support plates, and the concrete beams with external steel packages are arranged between the limit columns and the installation ring frame.

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