Underground structure bottom plate lattice column joint waterproof system
By combining a multi-layer waterproofing system and mature materials at the grid column joints of the underground structure's base slab, the leakage problem of the underground structure's base slab was solved, achieving both high-efficiency waterproofing and ease of construction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI MUNICIPAL ENG DESIGN INST (GRP) CO LTD
- Filing Date
- 2025-07-18
- Publication Date
- 2026-07-21
AI Technical Summary
Leakage is prone to occur at the joints of the lattice columns in the base slab of the underground structure. Existing waterproofing measures are difficult to effectively seal and repair, which leads to the easy displacement and cracking of the joint surface between the concrete and the steel, affecting the quality of waterproofing.
The system utilizes mature materials such as waterproof membrane, water-swellable sealant, polymer cement mortar, and waterproof coating, combined with steel gusset plates and water-stop steel plates to form a multi-layer waterproof system. The system is then constructed using a needle-type grouting device to ensure density and reinforcement.
It achieves effective waterproofing of the underground structure's base slab, making up for the shortcomings of existing waterproofing technologies. The construction is simple and the effect is significant, and it can repair leaks in a timely manner.
Smart Images
Figure CN224531754U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of waterproofing treatment technology for the bottom slab of open-cut tunnels or underground engineering structures, specifically relating to a waterproofing system for the grid column joint of the bottom slab of an underground structure. Background Technology
[0002] Currently, with the increasing impact of urban development on the landscape, the development of underground space (including open-cut tunnels in urban areas) is gaining favor among project decision-makers, especially in densely populated areas with scarce land. The development and utilization of underground space has become a major measure to compensate for insufficient land resources and make full use of limited land resources. The primary issue that needs to be addressed in the development of underground space is the foundation pit engineering for the main structure. As foundation pits become increasingly deeper, larger, and more irregular, the span of the foundation pit supports is becoming larger. To maintain the stability of the supports, column supports are required, and connecting beams are needed between multiple (rows of) columns to connect the columns into a whole, enhancing the stability of the columns and reducing horizontal displacement. The second issue that needs to be addressed in the development of underground space is ensuring that the concrete is leak-proof and minimizing the number and depth of cracks while maintaining safety and economy, which has greater engineering significance and social value.
[0003] Foundation pit supports are generally composed of reinforced concrete or steel sections. The columns are typically lattice columns made of single steel sections, steel pipes, or multiple steel sections. Due to their better stability and greater economy, lattice columns are the most commonly used column type. To provide vertical support for the underground structure, bored piles are often installed below the structure. Inserting lattice columns into these piles significantly increases their bearing capacity, effectively achieving "one pile, two uses." The lattice columns can only be cut after the top slab of the structure has been poured and reached sufficient strength to support the entire upper load, thus freeing up usable space between the top and bottom slabs. Consequently, the steel lattice columns inevitably remain embedded in the concrete structure where they pass through the top and bottom slabs, creating a discontinuous surface—the contact surface between the steel section and the concrete—in the otherwise intact concrete structure. The relatively small internal dimensions of the steel lattice columns make it difficult to achieve a dense concrete structure, easily leading to voids. This significantly compromises the waterproofing quality at these points. Furthermore, because the vertical support stiffness of the bored piles is much higher than that of the soil at the bottom of the pit, they bear the brunt of the load on the structure above, resulting in a "point-support" structure for the base slab and creating localized shear forces. The greater the load on the base slab, the greater the localized shear forces, making the interface between the concrete and the steel lattice more prone to slippage and cracking. This aptly illustrates the increased likelihood of leakage at lattice columns in open-cut tunnel engineering. Utility Model Content
[0004] In view of this, the purpose of this utility model is to provide a waterproofing system for the grid column joint of underground structure base plate to solve the shortcomings of the prior art.
[0005] To achieve the above objectives, this utility model is implemented through the following technical solution:
[0006] A waterproofing system for the lattice column joints of an underground structure is provided. The underground structure, from bottom to top, includes a foundation, a plain concrete pad, and a base slab. The base slab includes lower reinforcement, structural load-bearing concrete, upper reinforcement, and a top layer. During construction, lattice columns are installed, penetrating the base slab and inserted into the lower bored piles. The lattice columns are formed by four vertically arranged angle steels welded together at intervals to form rectangular columns. A waterproof membrane is installed below the structural load-bearing concrete, and reinforced waterproof membrane is installed at the edge of the pile head of the bored piles. The corners of the reinforced waterproof membrane are sealed with sealant, and waterproof coating is applied to the joint between the top of the bored pile and the structural bearing concrete. A water-stop steel plate is welded to the steel gusset plate located inside the structural bearing concrete. A first water-swellable sealant is applied to the corner of the weld between the steel gusset plate and the water-stop steel plate. Grouting is performed on the inner surface of the steel gusset plate. Polymer cement mortar is applied to the top of the lattice column. A second water-swellable sealant is applied to the joint between the polymer cement mortar and the upper layer of the base plate. A thin waterproof tape is pasted on top of the second water-swellable sealant.
[0007] As described in the underground structure base slab lattice column joint waterproofing system, the sealant is a low-modulus polyurethane sealant.
[0008] As described in the underground structure base slab lattice column joint waterproofing system, the waterproofing layer is polymer cement mortar.
[0009] As described in the underground structure base slab grid column joint waterproofing system, the waterproof coating is a sprayable cement crystallizing material.
[0010] As described in the underground structure base slab lattice column joint waterproofing system, a groove is chiseled out on the upper layer of the base slab, the plane of the groove is larger than the projection plane of the lattice column, and the bottom of the groove does not expose the upper layer of the base slab reinforcement.
[0011] The beneficial effects of this utility model's technical solution are:
[0012] The present invention has the following significant technical features based on the above-mentioned scheme: First, the materials used are simple, including mature waterproof membranes, water-swellable sealing adhesives, polymer cement mortar, waterproof tapes, and waterproof coatings, which are readily available; Second, the construction is convenient and technically simple, with most on-site operations being manual, and the use of syringe grouting equipment during grouting is also very convenient; Third, the waterproofing measures are effective, making up for the shortcomings of conventional waterproof membrane laying and single water-stop steel plate installation schemes, while also overcoming the drawbacks of these measures being unable to be supervised, unable to evaluate the effect afterward, and unable to be repaired. Attached Figure Description
[0013] To further illustrate the above-mentioned objectives, structural features, and effects of this utility model, the following will describe this utility model in detail with reference to the accompanying drawings.
[0014] Figure 1 This is a schematic diagram of the overall structure of a preferred embodiment of the present invention;
[0015] Figure 2 for Figure 1 Cross-sectional view of the waterstop section of the steel plate (section 1-1);
[0016] Figure 3 for Figure 1 Sectional view of the top of the midsole plate (section 2-2);
[0017] Figure 4 for Figure 1 Medium-sized sample A;
[0018] Figure 5 for Figure 1 Medium-sized sample B;
[0019] In the diagram: 0-1, Foundation; 0-2, Plain concrete cushion layer; 0-3, Lower layer reinforcement; 0-4, Structural load-bearing concrete body; 0-5, Upper layer reinforcement of the base slab; 0-6, Upper layer of the base slab; 0-7, Steel gusset plate; 0-8, Angle steel; 0-9, Weld; 1, Drilled pile; 2, Waterproof membrane; 3, Reinforced waterproof membrane; 4, Waterproof coating; 5, Low modulus polyurethane sealant; 6, Thin waterproof tape; 7, Polymer cement mortar; 8, Water-stop steel plate; 9, First water-swellable sealant; 10, Weld; 11, Second water-swellable sealant. Detailed Implementation
[0020] The terms “utility model” and “this utility model” used in this specification are intended to broadly refer to all subject matter of this specification and any of the following patent claims. Statements containing these terms should not be construed as limiting the subject matter described herein or limiting the meaning or scope of any of the following patent claims. Furthermore, this specification does not attempt to describe or limit the subject matter covered by any claim of any particular component, paragraph, statement, or drawing of this application. The subject matter should be understood with reference to the entire specification, all drawings, and any of the following claims. This utility model may have other embodiments and be practiced or implemented in other ways. Moreover, it should be understood that the wording and terminology used herein are for illustrative purposes and should not be considered limiting.
[0021] The details of the present invention will now be discussed with reference to the accompanying drawings, which are illustrated by way of example only. In the drawings, similar features or components may be labeled with the same reference numerals.
[0022] The use of the terms "comprising," "having," and "including," and variations thereof, herein means to include the items listed herein, their equivalents, and additional items. While reference may be made in the description of the drawings to directions such as above, below, upward, downward, backward, bottom, top, front, rear, etc., for convenience, reference is made relative to the drawings. These directions are not intended to literally accept or limit the invention in any form. Furthermore, terms such as "first," "second," "third," etc., are used herein for illustrative purposes and are not intended to indicate or imply importance or significance.
[0023] See Figures 1 to 5 As shown, this utility model provides a waterproofing system for the lattice column joint of an underground structure. The underground structure, from bottom to top, includes a foundation 0-1, a plain concrete cushion layer 0-2, and a base slab. The base slab includes lower reinforcing bars 0-3, a structurally load-bearing concrete body with self-waterproofing capabilities 0-4, upper reinforcing bars 0-5, and an upper layer 0-6. During the construction of the underground structure, lattice columns are installed, penetrating the base slab and inserted into the lower bored piles 1. The lattice columns are formed by four angle steels 0-8 arranged vertically and welded together with steel gusset plates 0-7 at intervals to form rectangular columns. A fully encased waterproof membrane 2 is installed below the structural load-bearing concrete body 0-4. A reinforced waterproof membrane 3 is installed at the edge of the pile head of the bored pile 1. Low-modulus polyurethane sealant 5 is used to seal the corners of the waterproof membrane 2 and the reinforced waterproof membrane 3. A waterproof coating 4 is applied to the joint between the pile top of the bored pile 1 and the structural load-bearing concrete body 0-4 to provide reinforcement when the lower waterproof membrane 2 and the reinforced waterproof membrane 3 are ineffective.
[0024] A water-stop steel plate 8 is welded onto the steel gusset plate 0-7 located inside the structural base plate 0-4. The corner of the weld point between the steel gusset plate 0-7 and the water-stop steel plate 8 is coated with the first water-swellable sealant 9. The welds 0-9 and 10 of the lattice column should be full and continuous, with a certain strength. The first water-swellable sealant 9 should be dense and without gaps at the corners.
[0025] At the top slab of the structure, the angle steel 0-8 face of the cut lattice column is lower than the top surface of the bottom slab 0-4. Poor-quality concrete slurry is poured into the angle steel 0-8 face. Grouting is applied to the inner surface of the steel gusset plate 0-7. Polymer cement mortar is applied to the top of the lattice column. A second water-swellable sealant 11 is applied to the joint between the polymer cement mortar and the top layer 0-6 of the bottom slab. A thin waterproof tape 6 is then pasted on top of the second water-swellable sealant 11 to effectively cover the joint. Inside the lattice column, if the concrete pouring quality cannot be guaranteed due to various reasons, resulting in internal voids, other measures can be used to detect these voids and grouting can be performed inside them.
[0026] It should be noted that this utility model does not impose restrictions on the size, type, or properties of the materials, which should be determined according to the actual engineering situation. However, it is essential to ensure that the water-swellable sealing adhesives are applied fully and densely to the gaps. The polymer cement mortar 7 has a certain bonding strength and compressive strength, while the thin waterproof tape 6 has strong adhesion and is as thin as possible.
[0027] The following explanation uses a cut-and-cover tunnel as an example.
[0028] Figure 1 This diagram illustrates the waterproofing measures for the lattice column joints in the tunnel roof slab. The tunnel structural base slab 0-4 is constructed with C40 waterproof concrete. Below the base slab 0-4, pre-laid reverse-adhesive waterproof membrane 2 (Type P) and pre-laid reverse-adhesive reinforced waterproof membrane 3 (Type P) are applied, with low-modulus polyurethane sealant 5 applied at the ends. To protect waterproof membrane 2 and enhance the adhesion of waterproof membrane 3, the underlying plain concrete pad 0-2 should have sufficient thickness and strength, preferably 200mm thick (C20). At the pile top, waterproof coating 4 is a spreadable cementitious crystallizing material, sprayed to a depth of at least 500mm beyond the outer edge of the pile. It is important to note that the pile top should not penetrate too much into the base slab, remaining below the lower layer of reinforcing steel 0-3. The bored pile 1 has a diameter of 800mm. The lattice column is composed of four L140×140 steel sections (angle steel 0-8). The steel gusset plate 0-7 is a 460mm×220mm steel plate with a thickness of 10mm, welded together. The vertical spacing of the steel gusset plates 0-7 is 220mm. According to the specifications, the lattice column should be inserted into the bored pile at least 4m. The spacing of the gusset plates within the base plate can be slightly adjusted, with the basic principle being not to affect the longitudinal and transverse main reinforcement. The waterstop steel plate 8 has a width of 700mm×700mm and a thickness of 10mm. The weld height 0-9 between angle steel 0-8 and steel gusset plate 0-7, between steel gusset plates 0-7, and between steel gusset plate 0-7 and waterstop steel plate 8 is 8mm. The steel grade of steel gusset plate 0-7, L140×140 steel section 0-8, and waterstop steel plate 8 is Q235B. Admittedly, the steel grade can be adjusted as needed without affecting the waterproofing effect.
[0029] All types of water-swellable waterproofing adhesives should be selected as hydrophilic adhesives with a certain expansion rate (volume expansion ratio not less than 400%) upon contact with water, and should be non-toxic, causing no environmental impact, and meeting the requirements of "Water-Swellable Waterproofing Adhesives" (JG / T312). The waterproof mortar should be a two-component, Class D material, meeting the requirements of "Polymer Cement Waterproof Mortar" (JC / T984). The thickness of the thin waterproofing tape should be as small as possible to have a certain degree of adaptability to horizontal and vertical vibration loads.
[0030] The above are merely preferred embodiments of the present utility model and are not intended to limit the implementation methods and protection scope of the present utility model. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A waterproofing system for the lattice column joint of an underground structure base slab, wherein the underground structure comprises, from bottom to top, a foundation, a plain concrete cushion layer, and a base slab, the base slab comprising a lower layer of reinforcing steel, structural load-bearing concrete, an upper layer of reinforcing steel, and an upper layer of the base slab; during the construction of the underground structure, lattice columns are installed, the lattice columns penetrating the base slab and inserted into the lower bored piles, characterized in that... The lattice column is formed by four vertically arranged angle steels welded together with steel gusset plates at intervals to form a rectangular column. A waterproof membrane is installed below the structural bearing concrete body. A reinforced waterproof membrane is installed at the edge of the pile head of the bored pile. The corners of the waterproof membrane and the reinforced waterproof membrane are sealed with sealant. A waterproof coating is applied to the joint between the pile top of the bored pile and the structural bearing concrete body. A water-stop steel plate is welded to the steel gusset plate located inside the structural bearing concrete body. A first water-swellable waterproof sealant is applied to the corner of the weld point between the steel gusset plate and the water-stop steel plate. Grouting is performed on the inner surface of the steel gusset plate. Polymer cement mortar is installed on the top of the lattice column. A second water-swellable waterproof sealant is applied to the joint between the polymer cement mortar and the upper layer of the base plate. A thin waterproof tape is pasted on top of the second water-swellable waterproof sealant.
2. The waterproofing system for the lattice column joints of the underground structure base slab as described in claim 1, characterized in that, The sealant is a low-modulus polyurethane sealant.
3. The waterproofing system for the lattice column joints of the underground structure base slab as described in claim 1, characterized in that, The waterproof layer is polymer cement mortar.
4. The waterproofing system for the lattice column joints of the underground structure base slab as described in claim 1, characterized in that, The waterproof coating is a sprayable cement crystallizing material.
5. The waterproofing system for the lattice column joints of the underground structure base slab as described in claim 1, characterized in that, A groove is chiseled out on the upper layer of the base plate. The plane of the groove is larger than the projected plane of the lattice column. The bottom of the groove does not expose the upper layer of the reinforcing steel on the base plate.