Press film sealing system and process based on in-situ material utilization and mechanical precision application

Abstract

The invention discloses a press film sealing system and process based on in-situ material utilization and mechanical precise construction, and relates to a lateral sealing link in vacuum pre-pressing technology. The invention includes partition boundary groove excavation, in-situ silt immediate structural protection wall construction, mechanical vertical active press film, film spreading and double-zone synchronous lapping. The invention constructs a collaborative sealing system including in-situ silt immediate structural protection wall, mechanical vertical active press film and double-zone synchronous integrated construction. The invention converts loose in-situ material into a structured sealing body, and combines with mechanical precise operation, fundamentally solves the pain points of sand soil intrusion leading to air leakage, secondary excavation causing disturbance, and strong material dependence and complicated process in traditional process, and significantly improves the sealing reliability, construction efficiency and engineering economy.

Description

Technical Field

[0001] This invention relates to the field of soft soil foundation reinforcement technology, specifically to the lateral sealing link in vacuum preloading technology, and in particular to a pressure membrane sealing system and process based on in-situ material utilization and precise mechanical application. Background Technology

[0002] In vacuum preloading soft soil treatment technology, to ensure the vacuum level under the membrane, an effective lateral seal must be formed around the reinforced area. Current technical approaches are mainly divided into three categories, but all have inherent limitations that affect sealing reliability, economy, or construction efficiency.

[0003] The first type of technology focuses on constructing a deep, vertically sealed curtain. For example, Chinese patent (CN117605001A) uses a cement-mixing pile isolation wall plus a clay-mixing pile sealing wall, with a pressure-membrane trench placed on top of the sealing wall. This method blocks horizontal seepage through deep mixing piles, offering high reliability, but it is costly, has a long construction period, and is only applicable to specific geological conditions. The pressure-membrane trench itself still relies on traditional backfilling, failing to address the problem of shallow sand intrusion into the trench wall, and the heavy pile foundation construction and pressure-membrane trench excavation are carried out in separate steps, making the process complex.

[0004] The second type of technology focuses on improving the sealing structure of the pressure membrane trench itself. For example, Chinese patent (CN103397626A) adds a groove to the bottom of the trench and uses clay and silt to backfill and cover the water in layers. This method improves the sealing effect by extending the sealing path and utilizing the properties of different materials. However, its essence is still a passive "excavation-external filling" mode: 1) It still needs to purchase or prepare specific clay, and has not gotten rid of the dependence on external materials; 2) The backfill material is a loose accumulation, which provides covering pressure to the sealing membrane rather than active lateral clamping and wrapping, and the membrane-soil interface strength is insufficient; 3) It fails to actively prevent the migration of sand from the trench wall to the sealing body during construction and vacuum preloading, and the risk of sand intrusion still exists.

[0005] The third category of technologies aims to eliminate or replace pressure membrane trenches. For example, Chinese patent (CN116591142A) uses a prefabricated floating raft-type cushion layer as a vacuum transfer and sealing unit, avoiding the excavation of pressure membrane trenches. This solution is highly innovative, but it relies on customized prefabricated components, resulting in high initial investment, limited applicability due to component specifications, and the inability to utilize in-situ materials, making it uneconomical in conventional large-area soft soil treatment projects. Chinese patent (CN116446376A) emphasizes a sealing wall plus manual pressure membrane application. However, the pressure membrane process relies on manual trampling, making the sealing quality highly susceptible to human factors, resulting in low efficiency, and it also fails to solve the problem of sand protection on the trench walls.

[0006] In summary, existing technologies share the following common shortcomings: 1) The lack of an active mechanism to prevent and drain sand intrusion makes the seal easily contaminated; 2) Highly dependent on materials, requiring either the purchase of clay from external suppliers or the use of prefabricated components; 3) Poor process coordination; vertical sealing, trench excavation, membrane laying and other processes are mostly separate, leaving room for efficiency improvement. 4) Membrane-soil interface sealing is passive, relying on covering rather than active clamping.

[0007] Therefore, this invention proposes an integrated process for achieving strong sealing of the membrane-soil interface through mechanized operations, which significantly improves construction efficiency and economy while ensuring reliability. Summary of the Invention

[0008] This invention addresses the common technical problems in existing vacuum pre-compression membrane trench construction, such as complex process connections, strong dependence on external materials, susceptibility of the sealing interface to sand intrusion, and easy disturbance and leakage caused by step-by-step construction. It proposes a membrane sealing system and process based on in-situ material utilization and precise mechanical application.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: The pressure sealing process based on in-situ material utilization and precise mechanical application includes the following steps: S1. Excavation of the boundary trench between adjacent vacuum preloading zones: At the boundary between two adjacent vacuum preloading zones, excavate the membrane sealing trench in one go along the predetermined line. The excavation must penetrate the upper permeable sand cushion layer down to the lower impermeable silt layer. The trench depth is dynamically adjusted based on the actual elevation of the top surface of the silt layer, the cross-sectional dimensions of the trench, and the requirements for membrane sealing construction to ensure that the overall shape of the trench is regular and meets the conditions for subsequent sealing construction.

[0010] S2. In-situ silt immediate structural wall construction: The wet and soft silt excavated from the impermeable silt layer in step S1 is immediately backfilled and compacted onto the sandy trench wall surface of the membrane trench to form a seepage-proof wall structure that is continuously distributed along the trench wall and tightly combined with the original soil layer. This structure is used to actively prevent sand particles from migrating into the trench from the outer permeable sand cushion layer. S3. Mechanized vertical active membrane pressing: The multi-layer sealing membrane is loosely laid along one side of the membrane pressing trench. Then, the membrane pressing equipment is used to press the stacked sealing membrane vertically downward along the trench wall direction into the seepage prevention and wall protection structure formed in step S2 and the original impermeable silt layer below to a set depth, so that the sealing membrane is tightly wrapped by the silt and forms a mechanically clamped sealing interface. S4. Simultaneous overlap of the sealing membrane and the two zones: Compact the silt backfilled in the trench, unfold the sealing membrane, and leave an overlap outside the trench. Connect the overlap of one layer of sealing membrane with the sealing membrane of the adjacent zone to complete the synchronous sealing of the two adjacent zones.

[0011] In step S1, the excavation width and slope gradient of the membrane pressing trench are dynamically adjusted according to the water content of the permeable sand cushion layer to maintain slope stability. If the water content of the permeable sand cushion layer is normal, the membrane pressing trench adopts the original excavation width and slope gradient; if the cushion layer is water-rich and the soil stability is poor, the trench is widened and the slope gradient is reduced simultaneously to control slope slippage. During construction, the plastic drainage boards inserted in the previous process are avoided, ensuring that the boards are intact and uninterrupted, and are smoothly led out along the trench wall.

[0012] In step S2, the construction of the seepage-proof wall structure is carried out simultaneously with or immediately after the excavation of the lower impermeable silt layer, and the average thickness of the constructed wall structure in the direction perpendicular to the trench wall is not less than 200mm.

[0013] Step S2 also includes: after constructing the seepage-proof wall structure, inspecting and ensuring that its outer surface is flat and free of sharp objects that could puncture the sealing membrane.

[0014] In step S3, the sealing membrane is pressed into the impermeable silt layer to a depth of not less than 0.5 meters.

[0015] In step S4, the overlap length of the sealing film outside the trench is not less than 2 meters. The connection between adjacent zone sealing films adopts a book-page type overlap method, that is, the sealing area pressed down and sealed is like the spine of a book, and the unfolded side films are like pages of a book. The sealing film in the large area and the unfolded sealing film for the pressure trench are connected by heat fusion or adhesive, and the adhesive width is not less than 100mm.

[0016] A pressure-membrane sealing system based on in-situ material utilization and precise mechanical application is used at the boundary of adjacent zones in vacuum preloading projects. The system includes: a pressure-membrane sealing system based on in-situ material utilization and precise mechanical application, characterized in that it is applied at the boundary of adjacent zones in vacuum preloading projects. The system includes: firstly, excavating a pressure-membrane trench between the permeable sand cushion layer and the impermeable silt layer, using the silt generated during excavation on-site, and constructing an anti-seepage retaining wall on the sandy trench wall; finally, using specialized pressure-membrane equipment, vertically pressing multiple layers of sealing membrane into the trench body, embedding them in the anti-seepage retaining wall and the lower impermeable silt layer to achieve a sealing effect.

[0017] The membrane pressing equipment includes an excavator, a detachable rectangular membrane pressing frame, and an intelligent water-air linkage system. The excavator is equipped with a detachable rectangular membrane pressing frame, which sinks with the help of the excavator's downward pressure and water pressure, and then the sealing membrane is vertically pressed down through air pressure sealing.

[0018] The key innovations of this invention are as follows: 1. The excavated high-plasticity silt is immediately used to construct a continuous and dense attached seepage protection wall on the exposed sandy trench walls. This wall is not simply backfilled, but serves as an active intrusion prevention barrier to permanently block the migration of particles from the outer sand cushion layer to the sealing area, fundamentally solving the core defect of sand contamination at the sealing interface in traditional processes.

[0019] 2. Using specialized molding equipment, the sealing membrane is pressed vertically and steadily into the constructed silt retaining wall and the underlying undisturbed silt, with a pressing depth of not less than 0.5m. This "vertical pressing" action ensures that the sealing membrane is completely enveloped by the plastic silt, creating an "embedded" high-strength sealing barrier, overcoming the limitations of traditional processes where the sealing membrane is only covered by loose material and has weak interfacial bonding.

[0020] 3. This invention is implemented at the boundary between zones, enabling the membrane pressing operation of two adjacent zones to be completed in one go, thereby reliably overlapping one layer of sealing membrane with the sealing membrane of the adjacent zone. This integrated process completely avoids the problems of secondary excavation disturbance and weak joints caused by traditional zoned and step-by-step construction.

[0021] This invention abandons the traditional passive mode of relying on purchased clay for backfilling and covering. Through process reconstruction and technological innovation, the excavated in-situ silt is immediately transformed into an impermeable structure for the trench wall. Specialized equipment is used to vertically embed the sealing membrane, completing the integrated sealing operation at the boundary of adjacent zones in one go. This effectively blocks the risk of air tightness at the source, significantly improving construction efficiency, sealing reliability and resource utilization. It forms a complete and efficient pressure membrane sealing solution, which is especially suitable for large-area soft soil foundation treatment projects. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the excavation of a permeable sand cushion layer; Figure 2 Schematic diagram of excavation and wall protection for impermeable silt layer; Figure 3 This is a schematic diagram of the membrane pressing process; Figure 4 This is a schematic diagram of mechanical film pressing. Figure 5 This is a schematic diagram of the membrane installation process; Figure 6 Cross-sectional view of the completed membrane structure; In the diagram: 1. Permeable sand cushion layer; 2. Impermeable silt layer; 3. Sealing membrane; 4. Drainage board. Detailed Implementation

[0023] 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, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be noted that directional or positional terms such as "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end" are defined based on the directional or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation or specific construction method for operation. Therefore, they should not be construed as limitations on this invention. Furthermore, terms such as "first" and "second" are used only for descriptive purposes and should not be construed as having relative importance.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "set up," and "deployed," etc., should be interpreted broadly. For example, the term "mold-fitting membrane" can refer to a permanent mold-fitting membrane, a temporary mold-fitting membrane, or an integrally formed mold-fitting membrane; the term "excavation" can refer to mechanical excavation or manual excavation; it can refer to direct deployment or deployment through preset points, or it can refer to excavation operations within a specific area. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] The following combination Figures 1 to 5 The preferred embodiments of the present invention will be described in detail below.

[0028] Example

[0029] The pressure-sealing process based on in-situ material utilization and precise mechanical application provided by this invention includes the following steps: S1. Excavation of the boundary trench between zones: See Figure 1In this embodiment, a 30-type bucket excavator is used to excavate along the designed axis, with an excavation width of 2 meters and a slope ratio of vertical to horizontal of 1:2. If water-rich sand layers cause slope instability, the slope can be widened to 2.2-2.5 meters to maintain construction safety. The excavated medium-coarse sand should be immediately and evenly spread on both sides of the trench top as a subsequent working cushion layer. Crucially, meticulous operation is required during excavation to ensure that the pre-installed plastic drainage boards 4 are not mechanically cut off. They must be smoothly led upwards along the excavated trench wall to the surface, ensuring that their extension into the horizontal drainage cushion layer within the sealed section is greater than 20 centimeters to maintain an effective drainage channel.

[0030] S2. In-situ silt immediate structured retaining wall construction: See Figure 2 After the sand cushion layer 1 is excavated to the design elevation, the next impermeable silt layer 2 is excavated downwards. In this embodiment, the excavation depth of this layer is 0.5 meters and the width is 0.4 meters, forming a trapezoidal trench that is narrower at the bottom and wider at the top. The core innovation of this step lies in the construction method of the retaining wall: instead of simply piling up the excavated silt or using it for backfilling the entire trench, it is immediately filled and manually or with the aid of tools patted and compacted onto the sloping surface of the trench wall formed by the permeable sand cushion layer 1, such as... Figure 2 The structure of the retaining wall is shown. This process requires speed and continuity, utilizing the high plasticity of the silt to ensure it adheres tightly to the sand wall, forming a dense, continuous seepage barrier extending along the trench wall with uniform thickness, typically 150-300 mm. The core function of this retaining wall is active isolation: before the sealing membrane 3 is laid, it permanently blocks the migration path of sand particles in the outer permeable sand cushion layer 1 towards the core sealing area inside the trench due to gravity, vibration, or vacuum suction. During construction, a dedicated person must inspect the exposed surface of the constructed retaining wall to ensure it is flat and free of sharp foreign objects such as shells and gravel to prevent damage to the subsequently laid sealing membrane.

[0031] S3, Mechanized Vertical Active Film Pressing: See Figure 3 , Figure 4 First, the four layers of sealing membrane 3 are loosely laid along one side of the pressing trench. Then, a pressing device is used. After the device is in place, its guiding mechanism clamps the stacked sealing membrane 3, while the driving mechanism provides a force perpendicular to the ground surface, pressing the sealing membrane 3 vertically and smoothly downwards along the constructed silt retaining wall surface. The sealing membrane 3 first penetrates the retaining wall structure and then embeds itself into the underlying original impermeable silt layer 2, with a total pressing depth of not less than 0.5 meters. This "vertical pressing" process (see...) Figure 3 (Arrow direction) allows the plastic sludge to be fully and tightly wrapped and embedded in the sealing membrane 3 from both sides and bottom, forming an "embedded" airtight seal with maximized contact area and strong interface bonding. This is fundamentally different from the traditional process where the sealing membrane is laid flat at the bottom of the trench and only covered by loose material.

[0032] S4. Simultaneous film spreading and dual-zone overlap: See Figure 5 After the membrane pressing process is completed, the small amount of loose silt backfilled in the trench is manually trampled or compacted with light tools to enhance its integrity. Then, the pressed-in sealing membrane 3 is unfolded, ensuring that the overlap length reserved on the outside of the trench is greater than 2 meters. Because the process of this invention is implemented in one go at the boundary between two zones, the membrane pressing trench and its sealing structure simultaneously serve two adjacent zones. Figure 4 and Figure 5 As shown, simply unfolding one layer (e.g., the third layer) of the sealing membrane 3 in this area and reliably overlapping it with the corresponding sealing membrane that has been laid or is laid simultaneously in the adjacent area can complete the boundary sealing of the two areas. This design completely eliminates the risks of secondary disturbance, joint misalignment, and sealing membrane damage caused by constructing one area first and then excavating the adjacent area in the traditional method.

[0033] See Figure 6 The diagram shows a cross-sectional view of the structure after the membrane is pressed in place. The final sealing system is clearly shown: a permeable sand cushion layer 1, an impermeable silt layer 2, a sealing membrane 3 vertically pressed and embedded in the structured retaining wall and silt layer, and a protected drainage board 4. This system integrates three main features: active intrusion prevention (retaining wall), enhanced interface sealing (vertical membrane embedding), and efficient collaborative construction (dual-zone synchronous construction).

Claims

1. A pressure-mold sealing process based on in-situ material utilization and precise mechanical application, characterized in that, Includes the following steps: S1. Excavation of the boundary trench between two adjacent vacuum preloading zones: At the boundary between two adjacent vacuum preloading zones, excavate the membrane trench along the preset line in one go; the excavation needs to penetrate the upper permeable sand cushion layer and down to the lower impermeable silt layer. The trench depth is dynamically adjusted based on the actual elevation of the top surface of the silt layer, the cross-sectional dimensions of the trench, and the requirements for pressure sealing construction, to ensure that the overall trench is well-formed and meets the conditions for subsequent sealing construction. S2. In-situ sludge immediate structural retaining wall construction: The wet and soft sludge excavated from the impermeable sludge layer in step S1 is immediately backfilled and compacted onto the sandy trench wall surface of the membrane trench, forming a seepage-proof retaining wall structure that is continuously distributed along the trench wall and tightly integrated with the original soil layer. This structure is used to actively prevent sand particles from migrating into the trench from the outer permeable sand cushion layer. The construction of the seepage-proof retaining wall structure is carried out simultaneously with or immediately after the excavation of the lower impermeable sludge layer. The average thickness of the constructed retaining wall structure in the direction perpendicular to the trench wall is not less than 200 mm. S3. Mechanized vertical active membrane pressing: Fold the special multi-layer sealing membrane at the membrane pressing trench position in half, loosely lay it along one side of the membrane pressing trench, and then use the membrane pressing equipment to press the stacked sealing membrane vertically downward along the trench wall direction into the seepage prevention and wall protection structure formed in step S2 and the original impermeable silt layer below for no less than 0.5 meters, so that the sealing membrane is tightly wrapped by the silt and forms a mechanically clamped sealing interface. S4. Film Expansion and Simultaneous Overlapping of Two Zones: After compacting the silt backfilled in the trench, unfold the folded sealing film and leave an overlap outside the trench. Connect the overlap of one layer of sealing film with the sealing film of the adjacent zone to complete the synchronous sealing of the two adjacent zones. The length of the overlap reserved outside the trench is not less than 2 meters. The connection between the sealing films of adjacent zones adopts a book-page type overlap method, that is, the sealing area of ​​the pressed sealing is like the spine of a book, and the unfolded two side films are like the pages of a book. The sealing film in the large zone and the unfolded sealing film of the pressure trench are connected by heat fusion or adhesive, and the bonding width is not less than 100mm.

2. The pressure-sealing process based on in-situ material utilization and precise mechanical application according to claim 1, characterized in that, In step S1, the excavation width and slope of the membrane trench are dynamically adjusted according to the water content of the permeable sand cushion layer. If the excavation width cannot guarantee the stability of the slope, the trench width should be appropriately widened. During the excavation process, it is ensured that the plastic drainage board pre-embedded in the previous process is not cut off and is smoothly led out along the trench wall.

3. The pressure-film sealing process based on in-situ material utilization and precise mechanical application as described in claim 1, characterized in that, Step S2 also includes: after constructing the seepage-proof wall structure, inspecting and ensuring that its outer surface is flat and free of sharp objects that could puncture the sealing membrane.

4. The pressure-film sealing system based on in-situ material utilization and precise mechanical application used in the process described in any one of claims 1-3, characterized in that, The system, applied at the boundary between adjacent zones in vacuum preloading projects, includes: firstly, excavating a membrane pressing trench between the permeable sand cushion layer and the impermeable silt layer, using the excavated silt on-site, and constructing an anti-seepage retaining wall on the sandy trench wall; finally, using a special membrane pressing equipment, vertically pressing multiple layers of sealing membrane into the trench body, embedding them in the anti-seepage retaining wall and the lower impermeable silt layer to achieve a sealing effect.

5. The pressure-sealing system based on in-situ material utilization and precise mechanical application according to claim 4, characterized in that, The membrane pressing equipment includes an excavator, a detachable rectangular membrane pressing frame, and an intelligent water-air linkage system. The excavator is equipped with a detachable rectangular membrane pressing frame. The frame sinks with the help of the excavator's downward pressure and water pressure, and then the sealing membrane is pressed vertically downward through air pressure sealing.

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