A foundation pit external corner area triangular frame underground continuous wall structure and a construction method thereof

Abstract

The application discloses a foundation pit external corner triangular frame underground continuous wall structure and a construction method, and relates to the technical field of foundation pit construction, in particular to a foundation pit external corner triangular frame underground continuous wall structure and a construction method. The foundation pit external corner triangular frame underground continuous wall structure comprises a triangular frame back-soil-side underground continuous wall, a triangular frame earth-facing-side underground continuous wall and an intermediate soil body; the triangular frame back-soil-side underground continuous wall is located at both sides of a foundation pit external corner and has an L-shaped structure; the triangular frame earth-facing-side underground continuous wall is located at the opposite side of the foundation pit external corner, two ends of the triangular frame earth-facing-side underground continuous wall are connected with the triangular frame back-soil-side underground continuous wall respectively, the triangular frame earth-facing-side underground continuous wall and the triangular frame back-soil-side underground continuous wall are connected to form a triangle, and the intermediate soil body is located in the region of the triangle. The application has the advantages of higher stability, better integrity and simpler construction process.

Description

Technical Field

[0001] This invention relates to the field of underground engineering construction technology, and in particular to a triangular frame underground continuous wall structure and construction method for the external corner area of ​​a foundation pit. Background Technology

[0002] Diaphragm wall retaining structures are a common construction support method for underground engineering. In foundation pits with regular shapes, they have high strength and good stability. However, when the foundation pit is irregular in shape, the stress is concentrated at the external corners of the foundation pit, which is prone to large displacement. Under the influence of the corner effect, large settlement is easily generated, which endangers the overall stability of the foundation pit support.

[0003] Currently, the common methods for dealing with the external corners of foundation pits include installing tie beams or pile structures at the corners. Installing tie beams at the corners allows for self-balancing on both sides, reducing the displacement of the support structure into the pit. However, this method only locally restricts displacement at the corner and has poor overall stability. Another common method is to install pile structures at the corners. This method improves overall strength and better restricts displacement at the corners, but its construction process is more complex and the budget is higher. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a triangular frame underground continuous wall structure and construction method for the external corner area of ​​a foundation pit, which has the advantages of higher stability, better integrity, and simpler construction process.

[0005] A triangular frame diaphragm wall structure for the external corner area of ​​a foundation pit includes a diaphragm wall on the back side of the triangular frame, a diaphragm wall on the front side of the triangular frame, and intermediate soil.

[0006] The diaphragm wall on the back side of the triangular frame is located on both sides of the external corner of the foundation pit, forming an "L" shape; the diaphragm wall on the front side of the triangular frame is located on the opposite side of the external corner of the foundation pit, and the two ends of the diaphragm wall on the front side of the triangular frame are respectively connected to the diaphragm wall on the back side of the triangular frame, and the diaphragm wall on the front side of the triangular frame and the diaphragm wall on the back side of the triangular frame are connected to form a triangle, and the middle soil is located within the area of ​​the triangle.

[0007] The aforementioned underground continuous wall structure with a triangular frame in the external corner area of ​​the foundation pit, wherein the triangle is an isosceles right triangle.

[0008] The aforementioned triangular frame diaphragm wall structure in the external corner area of ​​the foundation pit has reinforcing ribs at the external corner of the diaphragm wall on the back side of the triangular frame.

[0009] The aforementioned triangular frame diaphragm wall structure in the external corner area of ​​the foundation pit, wherein the side of the diaphragm wall facing away from the soil on the opposite side of the triangular frame is connected to the outer soil.

[0010] The aforementioned triangular frame diaphragm wall structure in the external corner area of ​​the foundation pit includes a main steel cage on the soil-backed side of the triangular frame diaphragm wall and horizontal steel cage bars and stirrups on the soil-facing side of the triangular frame diaphragm wall.

[0011] A construction method for a triangular frame diaphragm wall structure in the external corner area of ​​a foundation pit includes:

[0012] S1, Level the site and measure and lay out the lines;

[0013] S2, guide wall construction, determining the axial position of the underground wall;

[0014] S3 is a mud preparation, using high-performance bentonite, soda ash, thickener and tap water as raw materials. Its purpose is to maintain the stability of the tank wall and prevent the tank wall from collapsing.

[0015] S4. Use a trenching machine to trench the diaphragm wall on the back side of the triangular frame. The diaphragm wall on the back side of the triangular frame is "L" shaped. When excavating the "L" shaped diaphragm wall on the back side of the triangular frame, first excavate one side of the trench section of the diaphragm wall on the back side of the triangular frame. After excavating to half of the design depth, excavate the other side of the diaphragm wall on the back side of the triangular frame to half of the design depth. The construction is carried out alternately until the design depth is reached.

[0016] S5. During trenching, follow the machine display and pay attention to correcting deviations at any time. The verticality of the trench for the diaphragm wall should not exceed 1 / 300. The guide rod of the trenching machine should be perpendicular to the trench section. The grab bucket should be opened and slowly lowered into the trench to grab the soil. It is strictly forbidden to lower the bucket quickly or lift it quickly. When the trench is finished, it should be lowered gently and lifted slowly to prevent damage to the trench wall and collapse. The trenching machine's excavation speed should be controlled at about 15m / h. When the trench bottom is 2-3m deep, a measuring rope should be laid to measure the depth to prevent over-excavation and under-excavation. During the excavation process, observe at any time whether the plane where the bucket arm is located is perpendicular to the plane where the trench section is located, and regularly observe the left and right deviation of the bucket arm. Pay attention to whether the speed is uniform during the sinking process. Rapid excavation is not advisable during trenching to prevent the trench wall from becoming unstable.

[0017] S6. Place a wall scrubber in the trench and clean the trench walls. The wall scrubber should be cleaned with water in time to remove debris.

[0018] S7, bottom cleaning and mud replacement, using the displacement method for bottom cleaning. The thickness of the sediment at the bottom of the tank should not exceed 100mm, and the mud concentration at 500mm from the bottom of the tank should meet the design requirements;

[0019] S8, hoist the main reinforcement and horizontal reinforcement of the steel cage, and insert the guide pipes at the external corner and the center of the two trenches of the underground continuous wall on the back side of the triangular frame, respectively.

[0020] S9, pour concrete (the joint pipes are located at the ends of the previous trench section, so no joint pipe is inserted here; the joint pipe is 1.5m higher than the underground continuous wall);

[0021] S10, construct the trench for the underground continuous wall section on the soil-facing side of the triangular frame. When constructing the trench, the method of first grasping the two sides and then grasping the middle is adopted. The subsequent steps are the same as those for the underground continuous wall section on the soil-reverse side of the triangular frame.

[0022] According to the present invention, the triangular frame diaphragm wall structure and construction method for the external corner area of ​​the foundation pit have higher stability, better integrity, and a simpler construction process. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the embodiments of the present invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, wherein:

[0024] Figure 1 This is a perspective view of a triangular frame underground continuous wall structure in the external corner area of ​​a foundation pit according to the present invention;

[0025] Figure 2 This is a top view showing the reinforcement details of a triangular frame underground continuous wall structure in the external corner area of ​​a foundation pit according to the present invention.

[0026] Figure 3 This is a diagram showing the placement of the joint pipe in a construction method for a triangular frame underground continuous wall structure in the external corner area of ​​a foundation pit, as described in this invention.

[0027] Figure 4 This is a three-dimensional view of the joint pipe and diaphragm wall in the construction method of a triangular frame underground continuous wall structure in the external corner area of ​​a foundation pit according to the present invention.

[0028] In the diagram, 1. Diaphragm wall on the back side of the triangular frame; 2. Diaphragm wall on the front side of the triangular frame; 3. Middle soil; 4. Outer soil; 5. Main reinforcement of the steel cage; 6. Horizontal reinforcement of the steel cage; 7. Stirrups; 8. Reinforcing bars; 9. Joint pipe; 10. The diaphragm wall that has been poured. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] like Figure 1-4As shown, a triangular frame diaphragm wall structure in the corner area of ​​a foundation pit includes a triangular frame diaphragm wall 1 on the back side of the soil, a triangular frame diaphragm wall 2 on the front side of the soil, and an intermediate soil body 3.

[0031] The triangular frame diaphragm wall 1 on the back side of the foundation pit is located on both sides of the external corner of the pit, forming an "L" shape. The triangular frame diaphragm wall 2 on the front side of the foundation pit is located on the opposite side of the external corner of the pit. The two ends of the triangular frame diaphragm wall 2 on the front side of the foundation pit are connected to the triangular frame diaphragm wall 1 on the back side of the foundation pit, and the triangular frame diaphragm wall 2 on the front side of the foundation pit and the triangular frame diaphragm wall 1 on the back side of the foundation pit are connected to form a triangle. The intermediate soil body 3 is located within the area of ​​the triangle. Specifically, the triangle is an isosceles right triangle.

[0032] In this embodiment, a reinforcing rib 8 is provided at the external corner of the diaphragm wall 1 on the back side of the triangular frame. The side of the diaphragm wall 2 on the front side of the triangular frame that faces away from the diaphragm wall 1 is connected to the outer soil 4.

[0033] The underground continuous wall 1 on the back side of the triangular frame is provided with main steel cage reinforcement 5, and the underground continuous wall 2 on the front side of the triangular frame is provided with horizontal steel cage reinforcement 6 and stirrups 7.

[0034] Both ends of the underground diaphragm wall 1 on the back side of the triangular frame and both ends of the underground diaphragm wall 2 on the front side of the triangular frame are connected to the joint pipe in the already poured diaphragm wall 10.

[0035] The construction method for the above-mentioned triangular frame diaphragm wall structure in the external corner area of ​​the foundation pit includes:

[0036] S1, Level the site and measure and lay out the lines;

[0037] S2, guide wall construction, determining the axial position of the underground wall;

[0038] S3 is a mud preparation, using high-performance bentonite, soda ash, thickener and tap water as raw materials. Its purpose is to maintain the stability of the tank wall and prevent the tank wall from collapsing.

[0039] S4. Use a trenching machine to trench the diaphragm wall on the back side of the triangular frame. The diaphragm wall on the back side of the triangular frame is "L" shaped. When excavating the "L" shaped diaphragm wall on the back side of the triangular frame, first excavate one side of the trench section of the diaphragm wall on the back side of the triangular frame. After excavating to half of the design depth, excavate the other side of the diaphragm wall on the back side of the triangular frame to half of the design depth. The construction is carried out alternately until the design depth is reached.

[0040] S5. During trenching, follow the machine display and pay attention to correcting deviations at any time. The verticality of the trench for the diaphragm wall should not exceed 1 / 300. The guide rod of the trenching machine should be perpendicular to the trench section. The grab bucket should be opened and slowly lowered into the trench to grab the soil. It is strictly forbidden to lower the bucket quickly or lift it quickly. When the trench is finished, it should be lowered gently and lifted slowly to prevent damage to the trench wall and collapse. The trenching machine's excavation speed should be controlled at about 15m / h. When the trench bottom is 2-3m deep, a measuring rope should be laid to measure the depth to prevent over-excavation and under-excavation. During the excavation process, observe at any time whether the plane where the bucket arm is located is perpendicular to the plane where the trench section is located, and regularly observe the left and right deviation of the bucket arm. Pay attention to whether the speed is uniform during the sinking process. Rapid excavation is not advisable during trenching to prevent the trench wall from becoming unstable.

[0041] S6. Place a wall scrubber in the trench and clean the trench walls. The wall scrubber should be cleaned with water in time to remove debris.

[0042] S7, bottom cleaning and mud replacement, using the displacement method for bottom cleaning. The thickness of the sediment at the bottom of the tank should not exceed 100mm, and the mud concentration at 500mm from the bottom of the tank should meet the design requirements;

[0043] S8, hoist the main reinforcement and horizontal reinforcement of the steel cage, and insert the guide pipes at the external corner and the center of the two trenches of the underground continuous wall on the back side of the triangular frame, respectively.

[0044] S9, pour concrete (the joint pipes are located at the ends of the previous trench section, so no joint pipe is inserted here; the joint pipe is 1.5m higher than the underground continuous wall);

[0045] S10, construct the trench for the underground continuous wall section on the soil-facing side of the triangular frame. When constructing the trench, the method of first grasping the two sides and then grasping the middle is adopted. The subsequent steps are the same as those for the underground continuous wall section on the soil-reverse side of the triangular frame.

[0046] In summary, the triangular frame diaphragm wall structure and construction method for the external corner area of ​​the foundation pit provided by the present invention have higher stability, better integrity, and a simpler construction process.

[0047] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0048] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A triangular frame underground continuous wall structure for the external corner area of ​​an excavation pit, characterized in that, This includes the diaphragm wall on the back side of the triangular frame, the diaphragm wall on the front side of the triangular frame, and the intermediate soil. The diaphragm wall on the back side of the triangular frame is located on both sides of the external corner of the foundation pit, forming an "L" shape; the diaphragm wall on the front side of the triangular frame is located on the opposite side of the external corner of the foundation pit, and the two ends of the diaphragm wall on the front side of the triangular frame are respectively connected to the diaphragm wall on the back side of the triangular frame, and the diaphragm wall on the front side of the triangular frame and the diaphragm wall on the back side of the triangular frame are connected to form a triangle, and the middle soil is located within the area of ​​the triangle.

2. The triangular frame underground continuous wall structure in the external corner area of ​​the foundation pit according to claim 1, characterized in that, The triangle is an isosceles right triangle.

3. The triangular frame underground continuous wall structure in the external corner area of ​​the foundation pit according to claim 1, characterized in that, The triangular frame is reinforced at the external corner of the underground continuous wall on the back side of the soil.

4. The triangular frame underground continuous wall structure in the external corner area of ​​the foundation pit according to claim 1, characterized in that, The side of the diaphragm wall facing away from the soil on the triangular frame is connected to the outer soil.

5. The triangular frame underground continuous wall structure in the external corner area of ​​the foundation pit according to claim 1, characterized in that, The underground continuous wall on the back side of the triangular frame is provided with main reinforcing bars of the steel cage, and the underground continuous wall on the front side of the triangular frame is provided with horizontal reinforcing bars and stirrups of the steel cage.

6. The construction method of the triangular frame underground continuous wall structure in the external corner area of ​​the foundation pit according to any one of claims 1 to 5, characterized in that, include: S1, Level the site and measure and lay out the lines; S2, guide wall construction, determining the axial position of the underground wall; S3, the mud is prepared using bentonite, soda ash, thickener and tap water as raw materials; S4. Use a trenching machine to trench the diaphragm wall on the back side of the triangular frame. The diaphragm wall on the back side of the triangular frame is "L" shaped. When excavating the "L" shaped diaphragm wall on the back side of the triangular frame, first excavate one side of the trench section of the diaphragm wall on the back side of the triangular frame. After excavating to half of the design depth, excavate the other side of the diaphragm wall on the back side of the triangular frame to half of the design depth. The construction is carried out alternately until the design depth is reached. S5. When trenching, follow the machine display and pay attention to correcting deviations at any time. The verticality of the trench for the diaphragm wall should not exceed 1 / 300. The guide rod of the trenching machine should be perpendicular to the trench section. The grab bucket should be opened and slowly enter the trench to grab soil. During the excavation process, observe at any time whether the plane where the bucket arm is located is perpendicular to the plane where the trench section is located. Observe the left and right deviation of the bucket arm at regular intervals and pay attention to whether the speed during the sinking process is uniform. S6. Place a wall scrubber in the trench and clean the trench walls. The wall scrubber should be cleaned with water in time to remove debris. S7, Bottom cleaning and pulp replacement, using the displacement method for bottom cleaning; S8, hoist the main reinforcement and horizontal reinforcement of the steel cage, and insert the guide pipes at the external corner and the center of the two trenches of the underground continuous wall on the back side of the triangular frame, respectively. S9, pour concrete; S10, construct the trench for the underground continuous wall section on the soil-facing side of the triangular frame. When constructing the trench, the method of first grasping the two sides and then grasping the middle is adopted. The subsequent steps are the same as those for the underground continuous wall section on the soil-reverse side of the triangular frame.

7. The construction method of the triangular frame underground continuous wall structure in the external corner area of ​​the foundation pit according to claim 6, characterized in that, In step S5, the trenching speed of the trenching machine should be controlled at around 15m / h. When the trench bottom is dug to 2-3m, a measuring rope should be laid to measure the depth.

8. The construction method of the triangular frame underground continuous wall structure in the external corner area of ​​the foundation pit according to claim 6, characterized in that, In step S7, the bottom is cleaned and the slurry is replaced. The bottom is cleaned by displacement method. The thickness of the sediment at the bottom of the tank is no more than 100 mm. The slurry concentration at 500 mm from the bottom of the tank meets the design requirements.

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