Lateral expansion waterproof layer protection lap joint method and underground structure obtained through method

Abstract

The invention belongs to the field of urban underground space, and provides a protection lap joint method for a lateral expansion waterproof layer and an underground structure obtained through the method, and the method comprises the steps that a foundation pit is excavated, the excavation part is the distance from the upper portion of a newly-built structure to the ground, then waterproof construction is carried out, and construction of a newly-built structure body is carried out; the fender posts and the existing structure are cut for the first time, so that the existing structure communicates with the newly-built structure; the protection plate is placed between the existing structure waterproof layer and the fender post; the fender posts and the existing structure are cut for the second time, and then the waterproof layer of the existing structure and the waterproof layer of the newly-built structure are in lap joint; and the newly-built structure and the existing structure are poured together.

Description

Technical Field

[0001] This invention belongs to the field of urban underground space, specifically relating to a method for lateral expansion and extension of waterproof layer protection overlap and the underground structure obtained by the method. Background Technology

[0002] With the continued acceleration of urbanization and the ever-increasing urban population density, surface space resources are becoming increasingly scarce. Consequently, the demand for the development and utilization of underground space is constantly rising, requiring not only more comprehensive functions but also higher standards for scale and comfort. However, early-constructed underground spaces generally suffer from problems such as small scale, limited functionality, and irrational layout, making them unable to meet the current needs of urban development and residents' lives. Therefore, underground space expansion projects are gradually increasing across various regions, becoming an important component of urban renewal and upgrading.

[0003] In the process of expanding underground space, the connection between the new structure and the existing structure is a critical link and also a difficult point in the construction. Because these connection nodes involve the connection between the old and new structures and the transformation of the stress system, they often become the weak points of the entire underground structure. During operation, leakage problems are very likely to occur, posing a threat to the normal use of the underground space and structural safety.

[0004] The core reason for the leakage in this area is that during the connection construction, in order to connect the old and new structures, it is necessary to cut and demolish the existing structure. This operation can easily damage the original waterproofing system of the existing structure, causing the waterproofing layer to crack and break. At the same time, due to factors such as construction space, working conditions, and the precision of the connection between the old and new structures, it is difficult to achieve a tight and effective overlap between the new and existing waterproofing layers, creating weak points in the waterproofing. Ultimately, this allows groundwater or other water sources to seep into the underground space through these gaps, causing leakage problems. Summary of the Invention

[0005] To address the technical problem that existing technologies in lateral expansion projects of underground structures easily damage the waterproof layer already laid on the pile surface, affecting the quality of the subsequent overlap between the old and new waterproof layers and creating potential leakage hazards, this invention discloses an existing method for lateral open-cut expansion and connection of underground structures, as well as the underground structure obtained by this method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention proposes a method for protecting and overlapping the lateral expansion and extension of the waterproof layer, comprising the following steps: Step 1 involves excavating the foundation pit, which extends from the top of the new structure to the ground surface. Waterproofing and construction of the main structure follow. Step 2: Perform the first cut on the retaining piles and the existing structure to connect the existing structure with the new structure; Step 3: Place the protective board between the existing waterproof layer and the retaining piles; Step 4 involves a second cut to the retaining piles and existing structure, followed by overlapping of the existing waterproofing layer with the new waterproofing layer. Step 5 involves casting the new structure together with the existing structure.

[0007] As a further technical solution, the protective plate extends in a wavy shape along the first direction, and its curvature gradually decreases along the second direction perpendicular to the first direction, gradually approaching the flat plate.

[0008] As a further technical solution, when the upper structure of the retaining pile is inserted, the end of the protective plate closest to the flat plate faces upward, and when the lower structure of the retaining pile is inserted, the end of the protective plate closest to the flat plate faces downward.

[0009] As a further technical solution, in step 2, the cutting area of ​​the first cut is located in the middle of the retaining pile along the height direction of the retaining pile.

[0010] As a further technical solution, in step 2, the cutting area of ​​the first cut is located in the middle of the existing structure along the height direction of the existing structure.

[0011] As a further technical solution, in step 4, the retaining piles are first cut a second time, and then the existing waterproof layer and the new waterproof layer are overlapped; the overlap position is located on the side of the existing structure. After the overlap is completed, the side wall of the existing structure is cut a second time and rebar is installed.

[0012] As a further technical solution, in step 1, when constructing the main structure of the new structure, rebar is pre-installed on the main structure.

[0013] As a further technical solution, after the second cutting of the retaining pile, the upper part is higher than the newly built structure, and the lower part is lower than the newly built structure.

[0014] As a further technical solution, after the existing structure is cut a second time, the upper and lower parts of its side walls are aligned with the newly built structure.

[0015] Secondly, the present invention proposes an underground structure, which is obtained by the above-mentioned method of lateral expansion and waterproof layer protection overlap.

[0016] The beneficial effects of this invention are as follows: During construction, this invention employs zoned planning, dividing the area into a first and second cutting zone based on the stress characteristics of the joint, clearly defining the cutting range and depth to prevent structural instability caused by overall demolition. Secondly, it emphasizes sequential control, demolishing the first cutting zone first, immediately installing protective plates for fixation, and then demolishing the second cutting zone to ensure the existing structure remains protected throughout the demolition process. Simultaneously, it strengthens precision control, accurately controlling cutting parameters to ensure a smooth connection between the cut surfaces of the two areas, laying the foundation for subsequent waterproofing layer overlap and permanent structure construction.

[0017] Meanwhile, the protective plate of this invention adopts a gradient corrugated structure design, precisely matching the contour shape of the cutting area based on the spatial dimensions and stress requirements of the connection parts. The corrugated structure effectively disperses external forces, enhancing the load-bearing capacity of the protective plate itself. Simultaneously, the arc-shaped contact form replaces the traditional planar contact, significantly reducing contact stress with existing structural cuts and preventing secondary damage to the cut edges. Its smooth arc-shaped design and gradient corrugated structure reduce frictional resistance during jacking operations, making subsequent jacking operations smoother and more efficient. It also provides guidance for structural positioning during the jacking process, ensuring operational accuracy. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a detailed drawing of an existing underground structure disclosed in this invention; Figure 2 This is a schematic diagram of the first cutting region division disclosed in this invention; Figure 3 This invention discloses the construction drawings for connecting existing underground structures. Figure 4(a) is a front view of the protective plate; Figure 4(b) is a three-dimensional view of the protective plate; Figure 4(c) shows the contact diagram between the protective plate and the waterproof layer; Figure 5 This is a diagram showing the cutting of redundant parts of the existing structure; Figure 6 This is a schematic diagram showing the connection between the existing structure and the new structure. The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0020] 1. Existing structure; 2. Existing structure waterproofing layer; 3. Retaining piles; 4. New structure; 5. New structure waterproofing layer; 6. Soil layer; 7. First cutting zone; 8. Protective plate; 9. Second cutting zone; 10. Rebar installation; Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. For ease of description, the words "up," "down," "left," and "right" appearing in this invention only indicate that they are consistent with the up, down, left, and right directions of the accompanying drawings themselves, and do not limit the structure. They are merely for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] As described in the background section, there are shortcomings in the existing technology. In order to solve the above-mentioned technical problems, this invention proposes a method for lateral open-cut expansion and connection of existing underground structures.

[0023] In a typical embodiment of the present invention, such as Figure 1 As shown, this embodiment provides a method for lateral open-cut expansion and connection of an existing underground structure and the underground structure obtained by the method.

[0024] In underground space expansion projects, construction must proceed according to standardized procedures: first, excavate the foundation pit and level the base; then, lay the waterproof layer (note that when laying the waterproof layer between the existing structure and the new structure, the reserved overlap portion must be placed on top and a sufficient length must be reserved to ensure that the subsequent overlap is tight and waterproof; at the same time, the reserved overlap portion must be protected by covering it with protective boards, geotextiles, etc., to avoid damage and contamination.), tie the main structural steel bars, pour the main structure, and reserve the overlap section of the waterproof layer at the connection location; then, carry out the connection construction. First, the first area is cut, precisely controlling the cutting range and depth. After cutting, a gradient corrugated protective plate is immediately placed as a protective layer. This device uses an arc-face contact design, minimizing damage to the existing structure and providing stable protection for subsequent operations, while also facilitating jacking operations. Next, the second area is cut, ensuring a smooth connection between the cut surfaces of the two areas. After all cutting procedures are completed, the focus is on the overlapping construction of the waterproof layer, ensuring a tight, gapless fit between the old and new waterproof layers. Finally, the permanent structure is constructed to solidify the joints, ensuring the overall stability and waterproofing of the structure. The specific construction method is as follows: Step 1. Construction of the four main structures: foundation pit excavation, waterproofing, and new construction. First, the foundation pit is excavated, covering the distance from the top of the new structure 4 to the ground surface. Then, waterproofing is carried out, a crucial step in preventing groundwater seepage and ensuring the usability of the underground space. Before construction, the foundation pit base must be thoroughly treated, removing debris and laitance, repairing cracks and pits, and ensuring the base is flat, firm, and clean. If the base is damp, a special waterproofing material for damp surfaces must be used. The waterproofing layer construction must strictly adhere to the design thickness and process requirements. For coatings, multiple coats must be applied evenly to ensure no missed areas or drips. For roll materials, precise laying, compaction, and air removal are necessary to prevent air pockets, and the overlap width of the roll material must meet the specifications. The key point here is to properly handle the waterproofing layer preparation: Based on the connection design between the new structure 4 and the existing structure 1, accurately calculate the reserved length. Sufficient overlap allowance for the waterproofing layer is typically reserved on both sides of the connection node. The reserved portion needs temporary protection, using a special protective film or sealing the ends of the roll material to prevent damage, contamination, or aging during construction. This lays the foundation for a tight overlap of the waterproofing layers of the new and old structures, mitigating the risk of leakage at the connection point from the outset. Finally, complete the main construction of the new structure 4; the waterproofing layer in this step corresponds to... Figure 2 The newly constructed waterproof layer 5; it should be noted that when constructing the main structure 4, reinforcement bars are pre-installed on the main structure.

[0025] Step 2. Cut the first cutting area. The retaining piles 3 and the existing structure 1 are cut for the first time, such as... Figure 2 As shown, the corresponding cutting areas for both are shown in the image. Figure 2 Cut the retaining piles 3 and the middle part of the existing structure 1 to connect the existing structure 1 with the new structure 4. Specifically, first cut the retaining piles 3 a second time, and then overlap the waterproof layer of the existing structure 1 with the waterproof layer 5 of the new structure. The overlap position is located on the side of the existing structure 1. After the overlap is completed, cut the side wall of the existing structure 1 a second time and install rebar.

[0026] In step 2, the cutting area of ​​the first cut is located in the middle of the retaining pile 3 along the height direction of the retaining pile 3.

[0027] In step 2, the cutting area of ​​the first cut is located in the middle of the existing structure 1 along the height direction of the existing structure 1.

[0028] Step 3. Insert the protective plate and secure it. By applying pressure to the protective plate with jacks, the protective plate 8 is placed between the existing structure 1, the waterproof layer 2, and the retaining piles 3. Figure 3To reduce the contact area between the protective plate and the waterproof layer, the protective plate 8 is designed with a gradually rounded outer edge and an overall isosceles triangle profile on its side. This facilitates the insertion of the protective plate without damaging the waterproof layer. The structure of the protective plate 8 is shown in Figures 4(a) and 4(b), and the contact diagram between the protective plate 8 and the waterproof layer is shown in Figure 4(c).

[0029] Specifically, as shown in Figures 4(a) and 4(b), the protective plate 8 extends in a wavy shape along the first direction, and its curvature gradually decreases along the second direction perpendicular to the first direction, gradually approaching the flat plate. Thus, when viewed from the side, the overall outline forms an isosceles triangle. Furthermore, during installation, the end of the protective plate 8 closest to the flat plate faces upwards during the installation of the upper structure, and the end of the protective plate 8 closest to the flat plate faces downwards during the installation of the lower structure. The upper structure and lower structure are respectively the upper and lower structures of the retaining pile after the first cutting.

[0030] In the above construction steps, the protective plate adopts a gradient corrugated structure design, which precisely matches the contour shape of the cutting area based on the spatial dimensions and stress requirements of the joint. The corrugated structure can effectively disperse external forces and enhance the load-bearing capacity of the protective plate itself. At the same time, the arc-shaped contact form replaces the traditional planar contact, significantly reducing the contact stress with the cut and avoiding secondary damage to the cut edge. Its smooth arc-shaped design and gradient corrugated structure can reduce the frictional resistance during jacking operations, making subsequent jacking operations smoother and more efficient. It also provides guidance for structural positioning during the jacking process, ensuring operational accuracy.

[0031] Step 4. Cutting the second cutting zone After securing the protective plate, the retaining pile 3 is cut a second time. Figure 5 As shown, note that the cutting machine must stop immediately when it reaches the protective plate to prevent damage to the waterproof layer. After cutting, clean the surrounding soil, inspect the waterproof layer, and overlap the existing structure's waterproof layer 2 with the new structure's waterproof layer 5. When laying the waterproof layer between the existing structure 1 and the new structure 4, ensure the reserved overlap portion is placed on top and has sufficient length to guarantee a tight fit and effective waterproofing. Simultaneously, protect the reserved overlap portion by covering it with protective boards, geotextiles, etc., to prevent damage and contamination. Overlap the waterproof layer retained after cutting the existing structure 1 to the reserved area in the new structure 4. Then cut the side wall portion of the existing structure 1 and install the reinforcing bars.

[0032] Furthermore, after the second cutting, the upper part of the retaining pile 3 is higher than the newly built structure 4, and the lower part is lower than the newly built structure 4.

[0033] Furthermore, after the second cut of the existing structure 1, the upper and lower parts of its side walls are aligned with the newly built structure 4.

[0034] Step 5: Construct permanent structures After completing the waterproofing overlap of the existing structure 1 and the new structure 4, formwork is erected according to the pre-installed rebar 10 in the existing structure 1 and the new structure 4. Then, concrete is poured to connect the existing structure 1 and the new structure 4. Figure 6 As shown, this makes the existing structure 1 and the newly built structure 4 form a whole; In the above construction method, the key technical points of sectional demolition must be strictly controlled: First, zoning planning should be carried out, dividing the first and second zones according to the stress characteristics of the joint parts, and clarifying the cutting range and depth to avoid structural instability caused by overall demolition; Second, attention should be paid to the sequence control, demolishing the first zone first, and immediately installing protective plates for fixation after completion, and then demolishing the second zone to ensure that the existing structure 1 is always in a protected state during the demolition process; At the same time, precision control should be strengthened, and cutting parameters should be precisely controlled to ensure that the cut surfaces of the two zones are flat and connected, laying the foundation for subsequent waterproof layer overlap and permanent structure construction.

[0035] Secondly, this embodiment proposes an underground structure, which is obtained by the above-mentioned method of lateral expansion and waterproof layer protection overlap.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for protecting and overlapping a laterally expanded waterproof layer, characterized in that, Includes the following steps: Step 1 involves excavating the foundation pit, which extends from the top of the new structure to the ground surface. Waterproofing and construction of the main structure follow. Step 2: Perform the first cut on the retaining piles and the existing structure to connect the existing structure with the new structure; Step 3: Place the protective board between the existing waterproof layer and the retaining piles; Step 4 involves a second cut to the retaining piles and existing structure, followed by overlapping of the existing waterproofing layer with the new waterproofing layer. Step 5 involves casting the new structure together with the existing structure.

2. The method for lateral expansion and reinforcement of waterproof layer protection overlap as described in claim 1, characterized in that, The protective plate extends in a wavy shape along the first direction, and its curvature gradually decreases along the second direction perpendicular to the first direction, gradually approaching the flat plate.

3. The method for lateral expansion and reinforcement of waterproof layer protection overlap as described in claim 1, characterized in that, When the upper structure of the retaining pile is installed, the end of the protective plate closest to the flat plate faces upwards; when the lower structure of the retaining pile is installed, the end of the protective plate closest to the flat plate faces downwards.

4. The method for lateral expansion and reinforcement of waterproof layer protection overlap as described in claim 1, characterized in that, In step 2, the cutting area of ​​the first cut is located in the middle of the retaining pile along the height direction of the retaining pile.

5. The method for lateral expansion and reinforcement of waterproof layer protection overlap as described in claim 1, characterized in that, In step 2, the cutting area of ​​the first cut is located in the middle of the existing structure along the height direction of the existing structure.

6. The method for protecting and overlapping the lateral expansion waterproof layer as described in claim 1, characterized in that, In step 4, the retaining piles are first cut a second time, and then the existing waterproof layer and the new waterproof layer are overlapped. The overlap is located on the side of the existing structure. After the overlap is completed, the side wall of the existing structure is cut a second time and rebar is installed.

7. The method for lateral expansion and reinforcement of waterproof layer protection overlap as described in claim 1, characterized in that, In step 1, when constructing the main structure of the new building, rebar is pre-installed on the main structure.

8. The method for protecting and overlapping the lateral expansion waterproof layer as described in claim 1, characterized in that, After the second cutting of the retaining piles, the upper part is higher than the newly built structure, and the lower part is lower than the newly built structure.

9. The method for lateral expansion and reinforcement of waterproof layer protection overlap as described in claim 1, characterized in that, After the existing structure is cut a second time, the upper and lower parts of its side walls are aligned with the newly built structure.

10. An underground structure, characterized in that, The underground structure is obtained by the lateral expansion and waterproof layer protection overlapping method described in any one of claims 1-9.

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