Building / structure grounding area multi-coupling damage collaborative protection method

Abstract

The invention belongs to the technical field of foundations, and particularly relates to a building / structure grounding area multi-coupling damage collaborative protection method. For existing and newly-built buildings / structures, foundation trenches are excavated, hydrophobic protective layers are sprayed on the surfaces of the buildings / structures to form an outer surface protection system, graded broken stone layers and geogrids are filled to construct an integrated reinforced complex, a deformation absorption system is formed, anti-seepage geotechnical cloth is laid, and a clay layer is compacted to construct an anti-seepage system. And a drainage system is formed through the preset slope surface and the drainage structure to achieve cooperative protection. The device integrates the functions of erosion resistance, deformation resistance, seepage prevention and drainage, can block water and salt migration, absorb frost heaving and salt heaving stress and improve the protection durability and adaptability, is suitable for salinized soil sites with different salt heaving and frost heaving grades, and can effectively delay the damage of a grounding area and guarantee the stability of buildings / structures.

Description

Technical Field

[0001] This invention belongs to the field of foundation technology, specifically relating to a method for coordinated protection against multiple coupling damage in the grounding area of ​​buildings / structures. Background Technology

[0002] Saline soil is a special type of soil and rock rich in soluble salts such as chlorides, sulfates, and carbonates, widely distributed in inland and coastal areas of Northwest my country. The ground contact area of ​​buildings (the core damage zone is the area 200-500mm above the ground) serves as the interface between the foundation and the surface environment, making it susceptible to severe damage due to the coupling effects of multiple factors: surface or near-surface water accumulation combined with rising underground capillary water carries large amounts of soluble salts to the ground contact area. Under freeze-thaw cycles, repeated dissolution and crystallization of salts cause volume expansion (salt swelling), while freezing and thawing of water cause changes in soil volume (frost swelling). Simultaneously, chloride ions erode the passivation film of reinforcing steel, leading to electrochemical corrosion. The expansion of rust products further exacerbates concrete cracking and spalling. Freeze-thaw cycles also accelerate the expansion of microcracks and surface erosion, forming a coupled chain of damage: "water accumulation → water-salt migration → frost swelling / salt swelling stress → corrosion damage."

[0003] Engineering surveys show that in saline soil areas, buildings and structures that have not taken effective protective measures will experience problems such as concrete surface peeling, cracking, and steel corrosion within 1 to 2 years. The damage is even more pronounced in coastal areas or in winter when salt is spread to melt snow.

[0004] Existing protective technologies have significant drawbacks: localized spraying of protective materials only provides short-term corrosion protection and cannot address the issues of stress release and water / salt migration inhibition, resulting in short-lived effects and high costs; replacement and dynamic compaction methods involve large-scale engineering projects and are costly, and dynamic compaction cannot solve the corrosion problem; chemical modification methods are easily inhibited by salt in saline soils, resulting in insufficient long-term durability; and the partition layer method, due to its limited materials or imperfect design, struggles to address both deformation and corrosion challenges, and its effectiveness diminishes over time. The core limitation of these existing technologies lies in their "single-function orientation," failing to recognize the "multi-coupling" nature of damage in ground-level areas of saline soil regions and thus unable to form a comprehensive governance logic. Therefore, there is an urgent need for a systematic protection solution that integrates drainage, deformation absorption, seepage prevention, and erosion prevention functions, and can synergistically address the multi-coupling damage. Summary of the Invention

[0005] This invention provides a collaborative protection method for multiple coupling damage in the grounding area of ​​buildings / structures, in order to solve the technical problems that existing protection technologies are mostly single-function oriented, unable to integrate drainage, deformation absorption, seepage prevention and erosion prevention functions to form a complete chain of governance logic, and have the problems of short-term protection effect, large amount of engineering work, high cost, insufficient durability, difficulty in coordinating the dual problems of deformation and corrosion, and easy decay of effect with long-term use.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A collaborative protection method for multiple coupling damage in the grounding area of ​​buildings / structures includes the following steps: Excavate foundation trenches around the grounding area of ​​existing buildings / structures. After excavating the foundation trenches, spray a protective layer on the outer surface of the grounding area of ​​existing buildings / structures. Then fill the foundation trenches with an integrated reinforced composite to construct a deformation absorption system. Lay impermeable geotextile on top of the deformation absorption system. Construct a pre-set slope on the ground around the grounding area of ​​existing buildings / structures and construct a drainage system around the slope.

[0007] The width of the foundation trench is 300~800mm, so that the trench completely covers the grounding area of ​​the existing building / structure and its surrounding areas prone to water accumulation; the grounding area of ​​the building / structure is the area within 500~800mm above and below the contact line between the foundation pit and the foundation soil of the building / structure.

[0008] After excavating the foundation trench, a protective layer is sprayed onto the outer surface of the grounding area of ​​the existing building / structure. Specifically, this involves removing floating dust, oil stains, and loose impurities from the outer surface of the grounding area of ​​the existing building / structure, and coating the outer surface of the grounding area of ​​the existing building / structure with a water-repellent material layer to form a capillary water-absorbing barrier.

[0009] The hydrophobic coating is applied using a two-coat spraying process. The first coat dries before the second coat is applied, with a coating amount of 0.2~0.5 kg / m³. 2 After spraying, allow the material to cure naturally for no less than 24 hours.

[0010] The process of filling the foundation trench with an integrated reinforced composite material specifically involves: layering graded crushed stone and horizontally laying geogrid in layers within the foundation trench to form an integrated reinforced composite material. The particle size of the graded crushed stone is 5~40mm, the thickness of each layer of graded crushed stone is 100~150mm, and the compaction degree is ≥90%. The tensile strength of the geogrid is ≥30kN / m, the overlap width of the geogrid is ≥200mm, and it is fixed with binding straps.

[0011] The process of laying impermeable geotextile on top of the deformation absorption system specifically involves: laying the impermeable geotextile completely on top of the deformation absorption system, then backfilling clay in layers on the impermeable geotextile and compacting it to form a compacted clay layer. The permeability coefficient of the impermeable geotextile is ≤10. -6 cm / s, the overlap width of the impermeable geotextile is ≥300mm, and it is sealed by hot welding or special adhesive; the thickness of the compacted clay layer is not less than 100mm, the thickness of the layered backfill is 150~200mm, and the compaction degree is ≥95%.

[0012] The method of constructing a pre-set slope around the ground of the existing building / structure grounding area and constructing a drainage system around the slope specifically involves: adjusting the ground around the existing building / structure grounding area to a slope with a gradient of ≥2%, with the slope direction away from the grounding area, and setting drainage ditches around the slope to form a drainage system.

[0013] During the construction of the drainage system, the drainage ditch is 1-2m away from the outer edge of the slope. The drainage ditch is lined with gravel with a particle size of 10-20mm as a filter layer, and the end of the drainage ditch is connected to the natural drainage channel.

[0014] For the protection of the grounding area of ​​newly constructed buildings / structures, the construction of the new buildings / structures must be completed before the foundation trench is excavated. Specifically, according to the design requirements of the new buildings / structures, the foundation pit is excavated and the pit treatment is completed. In the foundation pit that has been treated and qualified, the foundation pit and grounding area of ​​the new buildings / structures are poured in accordance with the design specifications. After the pouring is completed, the outer surface of the grounding area of ​​the newly constructed buildings / structures is sprayed with a protective layer that is the same as the outer surface of the grounding area of ​​the existing buildings / structures.

[0015] The construction of the foundation pit and grounding area of ​​the newly built / structured building is completed. After the construction is completed, the foundation pit and grounding area of ​​the newly built / structured building are cured. The curing time is determined according to the structure type. The curing time for concrete structures is not less than 7 days, and the curing time for masonry structures is not less than 3 days.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention proposes a synergistic protection method for multiple coupling damage in the grounding area of ​​buildings / structures. A protective layer is formed by spraying a siloxane-based hydrophobic material onto the outer surface of the existing building / structure grounding area. Before spraying, surface dust, oil, and loose impurities are removed to ensure a tight adhesion between the protective layer and the grounding area surface, preventing the protective layer from detaching and failing due to adhering impurities. The siloxane-based hydrophobic material itself has excellent hydrophobic properties, forming a dense capillary water-absorbing barrier on the grounding area surface, effectively blocking the penetration of water and soluble salts carried in the water into the grounding area, reducing the risk of corrosion caused by water and salt migration at the source. Simultaneously, a two-coat spraying process is employed, with the second coat applied only after the first coat has dried. Strict control of the spraying amount and ensuring a natural curing time of no less than 24 hours further improve the uniformity and density of the protective layer, enhancing its durability and ensuring long-term anti-corrosion performance, effectively delaying concrete spalling and steel reinforcement corrosion.

[0017] Furthermore, this invention constructs a deformation absorption system by filling the foundation trench with an integrated reinforced composite. This is achieved through layered filling of graded crushed stone and horizontal laying of geogrid, allowing the graded crushed stone and geogrid to form an organic whole, fully leveraging their synergistic effect. The particle size of the graded crushed stone is controlled within a reasonable range, and the thickness and compaction of each layer meet specified requirements, ensuring sufficient strength and stability for the deformation absorption system. Simultaneously, it possesses good flexibility and toughness, effectively absorbing deformation stresses caused by salt heave and frost heave, preventing stress concentration that could lead to cracking and damage in the grounding area of ​​the building / structure. The geogrid's tensile strength meets standard requirements, with sufficient overlap width and secured with binding straps, effectively enhancing the integrity and tensile strength of the integrated reinforced composite, preventing delamination and displacement of the composite, further improving the stress buffering effect of the deformation absorption system, ensuring its long-term stable deformation absorption function, and mitigating the damage to the building / structure caused by multiple deformation stresses.

[0018] Furthermore, this invention lays an impermeable geotextile on top of the deformation absorption system, and then backfills and compacts clay in layers on the geotextile to form a compacted clay layer, constructing a dual impermeable system that significantly improves impermeability. The permeability coefficient of the impermeable geotextile is controlled within a specified range, effectively blocking surface water and groundwater from seeping into the deformation absorption system, preventing water immersion from causing a decrease in composite strength and a reduction in deformation absorption capacity. Sufficient overlap width of the geogrid, sealed with hot welding or a special adhesive, eliminates the risk of leakage at the overlaps, ensuring the impermeable geotextile forms a complete impermeable barrier. The thickness of the compacted clay layer is not less than the specified value, and the backfill thickness and compaction meet the requirements, protecting the impermeable geotextile from scratches and damage by sharp objects, and further enhancing the impermeability, forming a closed impermeable system. This dual protection effectively blocks the migration path of water and salt, providing a stable, water-free erosion environment for the grounded area.

[0019] Furthermore, this invention constructs a pre-defined slope around the ground surface of the building / structure's grounding area and builds a drainage system around the slope to form active drainage protection, effectively solving the coupling damage problem caused by water accumulation. Adjusting the ground to a specified slope and direction away from the grounding area guides surface runoff to flow quickly away from the grounding area, preventing water from stagnating around the grounding area and reducing the possibility of water infiltration and capillary rise. Drainage ditches are set up around the slope, and the distance between the drainage ditches and the outer edge of the slope is controlled. Crushed stone is laid in the drainage ditches as a filter layer, which effectively filters impurities in the runoff, prevents siltation and blockage, and enhances drainage capacity, ensuring rapid drainage. The ends of the drainage ditches connect to natural drainage channels, enabling the drainage system to connect with the existing drainage facilities on site, forming a complete drainage chain. This fundamentally reduces problems such as water-salt migration and exacerbated frost heave and salt expansion caused by water accumulation, further improving the overall effectiveness of the protection system.

[0020] Furthermore, this invention addresses the protection of grounding areas of newly constructed buildings / structures. It specifies that the construction of the new building / structure, foundation pit treatment, and pouring should be completed before the foundation trench excavation. After pouring, standardized curing should be performed, followed by spraying with a protective layer identical to that of existing buildings / structures' grounding areas. This ensures the continuity and uniformity of grounding area protection for new buildings / structures. A reasonable curing time is determined based on the structural type, with concrete and masonry structures following their respective curing requirements. This guarantees that the structural strength of the grounding area of ​​the new building / structure meets standards, preventing cracking of the protective layer and structural damage due to insufficient structural strength. This lays a solid foundation for subsequent protective construction, ensuring that the protective effect of the grounding area of ​​the new building / structure is consistent with that of existing buildings / structures, achieving collaborative protection throughout the entire life cycle.

[0021] Furthermore, this invention clearly defines the width of the foundation trench, the range of the grounding area, various material parameters, and construction process requirements to ensure the operability and standardization of each technical means, while also considering versatility and adaptability. A reasonable foundation trench width ensures that the trench completely covers the grounding area and its surrounding areas prone to water accumulation, avoiding localized damage due to insufficient protection. Clearly defining the specific range of the grounding area allows for precise location of key protection areas, improving the targeted nature of protection and avoiding resource waste. The standardized requirements for various material parameters and construction processes ensure that each protective structure meets the design protection standards, achieving synergistic performance of each function and guaranteeing the stability and durability of the protection system.

[0022] Furthermore, the present invention can adjust the safety factor by measuring the salt swelling deformation and frost swelling deformation, recalculate the thickness of the deformation absorption system to ensure that the thickness is not less than 200mm, and the other construction process parameters can be adapted and adjusted according to the corresponding salt swelling and frost swelling levels, all of which can achieve the same multi-coupling damage synergistic protection effect. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a collaborative protection method for multiple coupling damage in the grounding area of ​​a building / structure according to an embodiment of the present invention; Figure 2 This is a schematic cross-sectional view of a partial protection method for the grounding area of ​​a building / structure, as described in an embodiment of the present invention.

[0024] Labeling Explanation: 1. Building / Structure; 2. Water-repellent coating; 3. Compacted clay layer; 4. Impermeable geotextile; 5. Integrated reinforced composite. Detailed Implementation

[0025] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0026] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0027] Example 1 This embodiment addresses the problem of multiple coupling damage in the grounding area of ​​existing buildings / structures by providing a collaborative protection method. Specifically, it proposes a collaborative protection method for multiple coupling damage in the grounding area of ​​buildings / structures, comprising the following steps: First, excavate a foundation trench around the grounding area of ​​the existing building / structure to provide working space for subsequent protective structure construction. The grounding area of ​​the existing building / structure is the area within 500-800mm above and below the contact line between the foundation pit and the foundation soil. After the trench excavation is completed, a protective layer is sprayed onto the outer surface of the grounding area of ​​the existing building / structure to isolate it from external corrosive media and protect the surface of the existing structure from damage. The protective layer is applied using a two-coat spraying process; the first coat dries before the second coat is applied. The spraying amount is 0.2-0.5 kg / m². After spraying, natural curing is performed for at least 24 hours. The spraying amount of the protective layer is adjusted according to the porosity of the substrate: 0.2-0.3 kg / m² for concrete substrates and 0.3-0.5 kg / m² for masonry substrates. Next, an integrated reinforced composite 5 is filled into the excavated foundation trench. Utilizing the flexibility and toughness of the integrated reinforced composite 5, a deformation absorption system is constructed. During the construction of the deformation absorption system, the particle size of the graded crushed stone is 5-40mm, the thickness of each layer of crushed stone is 100-150mm, and the compaction degree is ≥90%. The tensile strength of the geogrid is ≥30kN / m, the overlap width of the geogrid is ≥200mm, and it is fixed with binding straps. The integrated reinforced composite 5, constructed from the graded crushed stone and the geogrid, absorbs the stress generated by the deformation of the surrounding soil, alleviating the squeezing damage to the existing structure. The thickness of the deformation absorption system is calculated based on the site's salt heave deformation and frost heave deformation, and the minimum thickness is not less than 200mm. Afterwards, an impermeable geotextile 4 is laid on top of the deformation absorption system. The permeability coefficient of the impermeable geotextile 4 is ≤10. -The flow rate is 6 cm / s. The overlap width of the geotextile 4 is ≥300mm, and it is sealed by hot welding or special adhesive. Then, clay is backfilled in layers on the geotextile 4 and compacted to form a compacted clay layer 3. The thickness of the compacted clay layer 3 is not less than 100mm, the thickness of each backfill layer is 150~200mm, and the compaction degree is ≥95%. The total thickness of the seepage prevention system is calculated and determined based on hydrological and meteorological data such as site precipitation, evaporation, and groundwater level. The geotextile 4 can block the infiltration of surface water and groundwater into the composite, preventing it from reducing its protective performance due to water immersion. Finally, the ground around the grounding area of ​​the existing building / structure is prepared into a pre-set slope. The slope direction is away from the grounding area, and drainage ditches are set on the periphery of the slope to form a drainage system, guiding the slope water to drain quickly and reducing the long-term erosion of the protective structure by water accumulation, thus forming a complete multi-coupling damage synergistic protection system. During the construction of the drainage system, the drainage ditch is 1~2m away from the outer edge of the slope, and the inner lining of the drainage ditch has a particle size of 10~20mm. The gravel serves as a filter layer, and the end of the drainage ditch is connected to the natural drainage channel.

[0028] Example 2 Based on the collaborative protection method for multiple coupling damage in the grounding area of ​​a building / structure described in Example 1, this example combines... Figure 1 and Figure 2 Taking the protection of the grounding area of ​​existing buildings / structures in saline soil areas, i.e., pile-column structures, as an example, this paper further details the method for coordinated protection against multiple coupling damage in the grounding area of ​​buildings / structures. The specific implementation method is as follows: First, construction preparation work is carried out, including site survey and grade determination. In this embodiment, the thickness of the deformation absorption system is determined strictly according to the results of frost heave and salt heave grade determination, combined with the calculated salt heave and frost heave amounts. The frost heave grade is determined according to Table G.0.1 of the "Code for Design of Building Foundations" (GB 50007-2011), and the salt heave grade is determined according to Table 4.3.6 of the "Technical Code for Construction in Saline Soil Areas" (GB / T 50942-2014). The thickness of the deformation absorption system is determined based on the calculated salt heave and frost heave amounts. The formula for calculating the thickness of the deformation absorption system is as follows:

[0029] Where: H is the thickness of the deformation absorption system, in mm; k is the safety factor, adjusted according to the type of saline soil, k=1.2~1.3 for chloride-saline soil and k=1.3~1.4 for sulfate-saline soil; δ s The measured salt swelling deformation is expressed in mm; δ f The measured frost heave deformation is in mm; the calculated thickness of the deformation absorption system must meet the requirement of a minimum thickness ≥ 200 mm.

[0030] In this embodiment, the measured salt heave deformation δs = 38 mm, which is classified as Grade I salt heave according to the standard; the average frost heave rate η is 10, and the frost heave deformation δs = 18 mm. f =42mm, judged as Level IV frost heave; the site is sulfate saline soil, and the safety factor k is taken as 1.3. Using the above formula for calculating the thickness of the deformation absorption system, the thickness of the deformation absorption system is calculated as: H=1.3×(38+42)=104mm; since in actual engineering, the soil compression and drainage space requirements need to be superimposed, the final calculated result of the deformation absorption system thickness is 280mm, which meets the requirement of minimum thickness ≥200mm.

[0031] Prepare graded crushed stone with a particle size of 5~40mm, geogrid with a tensile strength of 32kN / m and a permeability coefficient of 6×10. -6 4. The materials used include a geotextile with a flow rate of cm / s, silane-based water-repellent materials, and cement-modified soil. The cement content in the cement-modified soil is 7%. All materials have undergone performance testing, and all indicators meet the project requirements. Simultaneously, construction equipment such as small excavators, manual shovels, high-pressure sprayers, small vibratory tampers, levels, measuring tapes, and plastic binding straps are prepared, ensuring that all equipment is in good condition and ready for immediate use.

[0032] The width of the foundation trench is 300~800mm, and the depth is controlled according to the design thickness of the deformation absorption system. The trench wall is flat and without collapse, and the trench area completely covers the grounding area and the surrounding areas prone to water accumulation. like Figure 2As shown, a ring-shaped foundation trench is excavated around the grounding area of ​​the pile structure. The trench walls are flat and without collapse, and the trench area completely covers the grounding area and surrounding areas prone to water accumulation. The trench width is 300~800mm. Specifically, the trench width was determined through 12 sets of comparative tests for different salt heave / frost heave levels and different building types: Under Level I salt heave / Level II frost heave, a width of 300~500mm can meet the requirements for construction operation and protection effectiveness; under Level II salt heave / Level III~IV frost heave, a width of 500~700mm can meet the thickness and stress diffusion requirements of the deformation absorption system; under Level III salt heave / Level V frost heave, a width of 700~800mm can ensure that the protection range completely covers the stress-affected area. Due to the existing saline soil in this embodiment... The building / structure type is Class I salt heave + Class IV frost heave. The aforementioned trench width ranges for Class II salt heave / Class III-IV frost heave: 500-700mm, and for Class I salt heave / Class II frost heave: 300-500mm. Considering these ranges, to ensure that deformation absorption and stress diffusion requirements are met, the higher value range is adopted. In this embodiment, the trench width is 600mm, which matches the width range for Class II salt heave / Class III-IV frost heave. This trench range can completely cover the grounding area of ​​the existing building / structure and its surrounding areas prone to water accumulation. The trench depth is 280mm, consistent with the thickness of the deformation absorption system. To prevent trench wall collapse, the trench walls adopt a stepped slope with a gradient of 1:0.3. After the bottom of the foundation trench is cleaned, if any loose soil layer is found on site, graded crushed stone is used to replace the area. The replacement thickness is 120mm. After replacement, the soil compaction reaches 91%, which meets the engineering bearing requirements.

[0033] After completing the foundation trench treatment, clean the surface of the pile structure grounding area, removing dust, rust, and loose concrete. The cleaning area extends 600mm above and below the contact line. Following cleaning, the surface is subjected to high-pressure air drying to ensure it is dry and clean. Then, a silane-based hydrophobic material is sprayed using a high-pressure sprayer to form a capillary water-absorbing barrier. Since the pile structure grounding area in this embodiment is a concrete substrate, the first coat of silane-based hydrophobic material is applied at a rate of 0.25 kg / m². 2 After standing for 5 hours, apply a second coat of paint, with a coverage of 0.25 kg / m². 2 After both coats are applied, allow the coating to cure naturally for 26 hours until it is fully cured. The cured coating should have no missed spots or runs to ensure that the protective effect meets the standards.

[0034] After the protective layer has fully cured, the filling construction of the integrated reinforced composite 5 begins. First, a 140mm thick layer of graded crushed stone is laid at the bottom of the foundation trench. After laying, it is compacted to a compaction degree of 92% to ensure the stability of the underlying foundation. Then, a geogrid is laid on the compacted graded crushed stone layer, completely surrounding the pile structure. The overlap width is controlled at 220mm, and it is secured every 250mm with binding straps to ensure a flat and firm geogrid installation. After the geogrid is fixed, another 140mm thick layer of graded crushed stone is laid, compacted, and then a second layer of geogrid is laid, fixed in the same way as the first layer, thus forming the integrated reinforced composite 5. The thickness of the integrated reinforced composite 5 is measured to be 280mm, consistent with the calculated thickness of the deformation absorption system, ensuring that it can completely absorb the deformation stress caused by site salt heave and frost heave, effectively performing its deformation absorption function.

[0035] After the integrated reinforced composite structure 5 is constructed, the seepage prevention system is installed. First, a geotextile 4 is laid on top of the deformation absorption system, extending 180mm beyond the edge of the trench. The overlap width between geotextiles 4 is controlled at 320mm, and the overlap is sealed using hot welding at a temperature of 220℃ to ensure effective seepage prevention. After the geotextile 4 is laid, cement-modified soil is backfilled in layers, each layer 180mm thick. After each layer, it is compacted using a rammer until the compaction reaches 96%. The backfilling is continued until level with the ground, forming a complete compacted clay layer 3, further strengthening the seepage prevention protection.

[0036] Following this, the drainage system was constructed. Construction workers used a level to adjust the ground slope around the piles, controlling it to 2.3% to ensure the slope direction was away from the pile ground contact area, facilitating surface water drainage. A drainage ditch was excavated 1.8m outside the protected area, with a width of 350mm and a depth of 450mm. An 80mm thick layer of crushed stone with a particle size range of 10-20mm was laid at the bottom of the ditch as a filter layer. The end of the ditch was connected to the site's natural drainage channel. To ensure ditch wall stability, the ditch walls were wrapped with geotextile for protection, guaranteeing the long-term smooth operation of the drainage system.

[0037] Finally, quality acceptance was carried out, which mainly included four aspects: external pipe inspection, parameter testing, water testing, and durability tracking. The external inspection focused on ensuring the water-repellent coating 2 was evenly laid without any missed areas or drips; the impermeable geotextile 4 was undamaged and laid flat; the compacted clay layer 3 had a smooth surface without cracks; and the drainage slope around the piles was smooth with no potential for water accumulation. Regarding parameter testing, the measured thickness of the deformation absorption system was 280mm, consistent with the previous calculation; the tensile strength of the geogrid met design requirements; the permeability coefficient of the impermeable geotextile 4 met the standard; and the compaction degree of the compacted clay layer 3 reached 96%. All parameters met the engineering design standards. The water testing used artificial spraying to simulate rainfall, controlling the rainfall at 30 mm. The spraying speed was mm / h, and the spraying continued for 30 minutes. After the test, there was no local water accumulation on the site, no wet traces under the anti-seepage layer, and the drainage channels were unobstructed. The anti-seepage and drainage effect met the standards. As for the durability tracking, the pile grounding area was monitored for 3 years after the construction was completed. The monitoring results showed that there was no cracking or peeling in the pile grounding area, and the steel reinforcement corrosion detection was normal. The overall protection effect was stable and reliable, achieving the design goal of multi-coupling damage synergistic protection.

[0038] Example 3 Based on the collaborative protection method for multiple coupling damage in the grounding area of ​​a building / structure described in Embodiment 1, this embodiment takes the protection of the grounding area of ​​a newly built wall in a saline soil area as an example to further explain the collaborative protection method for multiple coupling damage in the grounding area of ​​a building / structure. The specific implementation method is as follows: The salt heave / frost heave level of the newly constructed wall grounding area in the saline soil area is classified as Grade I salt heave + Grade III frost heave. First, a site survey and grade determination were conducted on the newly constructed wall grounding area in the saline soil area. The measured salt heave deformation δs = 33 mm, which, according to the standard, is classified as Grade I salt heave. The average frost heave rate η is 5, and the frost heave deformation δs... f=37mm, judged as Level III frost heave. The ground contact area of ​​the newly built wall in the saline soil area is chloride-saline soil, so a safety factor k of 1.25 is selected. Using the thickness calculation formula of the deformation absorption system in Example 2, the thickness of the deformation absorption system is calculated as: H=1.25×(33+37)=87.5mm, which is 87.5mm. In actual construction, combined with the deformation transmission characteristics of the linear structure of the wall and the reserved drainage space for correction, the thickness of the deformation absorption system is finally determined to be 240mm, which meets the minimum thickness requirement of not less than 200mm for the project. At the same time, hydrological data of local annual precipitation of 630mm and groundwater depth of 1.4m are collected, and the total thickness of the seepage prevention system is calculated to be 300mm, of which the thickness of the compacted clay layer 3 is 160mm, which meets the minimum thickness requirement of not less than 100mm for the project. Prepare the necessary materials, including graded crushed stone with a particle size range of 5-40mm; geogrid with a tensile strength of 35kN / m; and impermeable geotextile with a permeability coefficient of 4×10⁻⁶. -6 cm / s, and at the same time prepare siloxane-based hydrophobic materials and lime soil, with a lime content of 10% in the lime soil; all prepared materials have been tested upon arrival, and their mechanical properties, impermeability and salt corrosion resistance all meet the design requirements.

[0039] After construction preparations are completed, the foundation excavation phase begins. According to the new wall design drawings, a strip foundation pit is excavated, with a width of 800mm and a depth of 1.0m, dimensions suitable for the wall foundation's bearing capacity requirements. During excavation, double-sided sump pits are installed for dewatering to prevent water accumulation and ensure the foundation's quality. The bottom of the pit is manually leveled and cleaned. After cleaning, a 100mm layer of graded crushed stone is laid and compacted to achieve a compaction degree of 93%, ensuring the foundation's bearing capacity meets design standards. A 1:0.5 slope is used around the pit for protection, and a geotextile layer is laid on the slope to prevent soil erosion. After the foundation excavation and treatment are completed and accepted, the next construction phase begins.

[0040] This embodiment employs a concrete shear wall structure. The reinforcement bars for the wall foundation and lower wall are tied according to design specifications, with the concrete cover thickness in the grounding area not less than 40mm. After the reinforcement is tied, C35 concrete is continuously poured. During pouring, an immersion vibrator is used to compact the concrete in layers to prevent quality defects such as honeycombing, pitting, and exposed reinforcement. The wall is poured to the design ±0.000 elevation. The grounding area, defined as the area 700mm above and below the contact line between the foundation and the subgrade soil, has its surface smoothed and polished. Strict measures are taken to prevent contamination or impact damage to the concrete surface during construction.

[0041] After the wall foundation and wall pouring are completed, wall curing will be carried out. Within 12 hours after the concrete pouring, the surface of the wall and foundation will be covered with impermeable geotextile and plastic film for moisture retention. Water will be sprinkled 2 to 3 times a day, with the frequency of watering increased appropriately during hot and dry periods. The curing period will last for a total of 10 days. During the curing period, a fence will be set up for protection to prevent external impacts to the wall and foundation or the stacking of materials around them, ensuring that the structural strength of the wall and foundation meets the standards, and the measured compressive strength of the concrete is not less than 85% of the design strength.

[0042] After curing, first clean the surface of the wall's grounding area, removing dust, concrete laitance, and debris. The cleaning area should extend 700mm above and below the contact line between the foundation and the subgrade soil. After cleaning, use a high-pressure air dryer to dry the surface, ensuring it is dry, clean, and free of loose material. Then, apply a two-coat application of a siloxane-based hydrophobic material using a high-pressure sprayer. Since the wall is made of concrete, the first coat should be applied at a rate of 0.2 kg / m². 2 After spraying, let it stand for 6 hours to allow the surface to dry before applying a second coat. The second coat should also be applied at a rate of 0.2 kg / m². 2 This forms an external surface protection system. During the spraying process, focus on covering the junction between the wall and the foundation to ensure no missed areas or drips. After both coats are completed, allow for natural curing for 24 hours, until the coating is fully cured and forms a dense capillary water-absorbing barrier, ensuring the effectiveness of the external surface protection.

[0043] After the external surface protection system is constructed, strip-shaped foundation trenches are excavated around the perimeter of the wall's grounding area, with the trenches continuously arranged along the length of the wall. Since the site in this embodiment has a geological type of Class I salt heave combined with Class III frost heave, the trench width is determined to be 700mm, which meets the 500-700mm range requirement for the corresponding salt heave and frost heave levels. The trench depth is set to 240mm, consistent with the thickness of the deformation absorption system determined in the previous calculations. The trench walls are smoothed to ensure no collapse risk. Graded crushed stone is layered at the bottom of the trench, with each layer being 120mm thick. A small vibratory rammer is used for compaction, achieving a compaction degree of not less than 91%. Geogrid is horizontally laid on each compacted crushed stone layer, continuously laid along the length of the wall. The overlap width is controlled at 250mm, and plastic binding tape is used to secure the overlaps every 300mm to prevent displacement or wrinkling of the geogrid. Repeat the above construction process to form an integrated reinforced composite 5, which constitutes a deformation absorption system. In actual measurements, the thickness of the integrated reinforced composite 5 in each section of the foundation trench is 240mm, which is consistent with the calculated value. It can effectively absorb salt swelling stress and frost swelling stress and play a role in deformation absorption.

[0044] After the deformation absorption system is constructed, a seepage prevention system is built on top of it. Specifically, a seepage-proof geotextile 4 is laid completely on top of the deformation absorption system, extending 150mm beyond the edge of the trench to ensure complete coverage of the entire protected area. The seepage-proof geotextile 4 is laid continuously along the length of the wall, with an overlap width of 350mm between layers. The overlaps are sealed using hot welding at a temperature of 230℃ to ensure no incomplete or missing welds, guaranteeing a leak-proof seal. Layers of lime-soil are then backfilled on top of the geotextile 4, each layer 160mm thick. A road roller is used to compact the backfill layer along the length of the wall, achieving a compaction degree of no less than 95%. Sharp tools are strictly avoided during backfilling to prevent scratching the geotextile 4. The moisture content of the lime-soil is controlled within the optimal range of 18%-22%. After compaction, the surface of the lime-soil is smooth and crack-free, and it adheres tightly to the wall sidewalls, forming a closed seepage-proof layer to further enhance the seepage prevention effect.

[0045] A level instrument was used to measure and adjust the ground slope around the wall in real time, ensuring that the slope was no less than 2.5% and that the slope direction was away from the ground contact area of ​​the wall. This ensured that the ground on both sides drained outwards, preventing surface water from accumulating in the ground contact area. A continuous drainage ditch was constructed 1.5m outside the protected area, along the length of the wall. The ditch had a cross-sectional dimension of 400mm width and 500mm depth. A 100mm layer of crushed stone with a particle size range of 10-20mm was laid at the bottom of the ditch as a filter layer to improve drainage efficiency. The end of the drainage ditch was connected to the municipal drainage network to form a drainage system. Due to the loose and easily collapsible local soil, the ditch walls were protected with mortar-grouted rubble masonry to prevent deformation and siltation, ensuring the long-term smooth operation of the drainage system.

[0046] Finally, quality acceptance was conducted in four aspects: external pipe inspection, parameter testing, water testing, and durability tracking. In the visual inspection, the compacted clay layer (i.e., lime-soil) surface was smooth and without cracks, the drainage slope was smooth, and the drainage ditch was constructed according to specifications and without damage. In the parameter testing, the measured thickness of the deformation absorption system was 240mm, consistent with the calculated value, and the compaction degree reached 91%; the tensile strength of the geogrid was 35kN / m, meeting the design requirements; and the permeability coefficient of the impermeable geotextile was 4×10⁴. -6The compaction rate of the compacted clay layer (layer 3) was 95%, meeting the seepage prevention standards. The ground slope was 2.5%, and all core construction parameters met the design requirements. During the water test, a simulated rainstorm scenario was conducted using artificial spraying, controlling the rainfall at 40 mm / h for 40 minutes. After the test, there was no localized water accumulation around the wall, no dampness below the seepage prevention layer, and the drainage ditch drained smoothly without leakage or siltation, indicating that the seepage prevention and drainage system met the performance standards. In the durability tracking, the grounding area of ​​the wall was monitored for three years after construction. The monitoring results showed that the grounding area of ​​the wall showed no damage or corrosion, good structural stability, and consistently reliable protective effect.

[0047] This invention is not limited to the above embodiments. For saline soil sites with Class I salt heave combined with Class IV frost heave or Class I salt heave combined with Class III frost heave, the safety factor k can be adjusted by measuring the salt heave deformation δs and frost heave deformation δf, and the thickness of the deformation absorption system can be recalculated to ensure that the thickness is not less than 200mm. Other construction processes and parameters can be adapted and adjusted according to the corresponding salt heave and frost heave levels, and all of them can achieve the same multi-coupled damage synergistic protection effect.

[0048] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for coordinated protection against multiple coupling damage in the grounding area of ​​a building / structure, characterized in that, Includes the following steps: Excavate a foundation trench around the grounding area of ​​the existing building / structure. After excavating the foundation trench, spray a protective layer on the outer surface of the grounding area of ​​the existing building / structure. Then fill the foundation trench with an integrated reinforced composite (5) to construct a deformation absorption system. Lay an impermeable geotextile (4) on top of the deformation absorption system. Construct a pre-set slope on the ground around the grounding area of ​​the existing building / structure and construct a drainage system around the slope.

2. The method for coordinated protection against multiple coupling damage in the grounding area of ​​a building / structure according to claim 1, characterized in that, The width of the foundation trench is 300~800mm, so that the trench completely covers the grounding area of ​​the existing building / structure and its surrounding areas prone to water accumulation; the grounding area of ​​the existing building / structure is the area within 500~800mm above and below the contact line between the foundation pit and the foundation soil of the building / structure.

3. The method for coordinated protection against multiple coupling damage in the grounding area of ​​a building / structure according to claim 1, characterized in that, After excavating the foundation trench, a protective layer is sprayed on the outer surface of the grounding area of ​​the existing building / structure. Specifically, the floating dust, oil stains and loose impurities on the outer surface of the grounding area of ​​the existing building / structure are removed, and a hydrophobic coating is applied to the outer surface of the grounding area of ​​the existing building / structure (2) to form a capillary water absorption barrier.

4. The method for coordinated protection against multiple coupling damage in the grounding area of ​​a building / structure according to claim 3, characterized in that, The hydrophobic coating (2) is applied using a two-coat spraying process. The first coat dries before the second coat is applied, with a coating amount of 0.2~0.5 kg / m³. 2 After spraying, allow the material to cure naturally for no less than 24 hours.

5. A method for coordinated protection against multiple coupling damage in the grounding area of ​​a building / structure according to claim 1, characterized in that, The process of filling the foundation trench with an integrated reinforced composite (5) specifically involves filling the foundation trench with graded crushed stone in layers and laying geogrid horizontally in layers to form an integrated reinforced composite (5). The particle size of the graded crushed stone is 5~40mm, the thickness of each layer of graded crushed stone is 100~150mm, and the compaction degree is ≥90%. The tensile strength of the geogrid is ≥30kN / m, the overlap width of the geogrid is ≥200mm, and it is fixed with binding straps.

6. The method for coordinated protection against multiple coupling damage in the grounding area of ​​a building / structure according to claim 1, characterized in that, The process of laying impermeable geotextile on top of the deformation absorption system specifically involves: laying the impermeable geotextile completely on top of the deformation absorption system, then backfilling clay in layers on the impermeable geotextile (4) and compacting it to form a compacted clay layer (3), wherein the permeability coefficient of the impermeable geotextile (4) is ≤10. -6 cm / s, the overlap width of the impermeable geotextile (4) is ≥300mm, and it is sealed by hot welding or special adhesive; the thickness of the compacted clay layer (3) is not less than 100mm, the thickness of the layered backfill is 150~200mm, and the compaction degree is ≥95%.

7. A method for coordinated protection against multiple coupling damage in the grounding area of ​​a building / structure according to claim 1, characterized in that, The method of constructing a pre-set slope around the ground of the existing building / structure grounding area and constructing a drainage system around the slope specifically involves: adjusting the ground around the existing building / structure grounding area to a slope with a gradient of ≥2%, with the slope direction away from the grounding area, and setting drainage ditches around the slope to form a drainage system.

8. A method for coordinated protection against multiple coupling damage in the grounding area of ​​a building / structure according to claim 7, characterized in that, During the construction of the drainage system, the drainage ditch is 1-2m away from the outer edge of the slope. The drainage ditch is lined with gravel with a particle size of 10-20mm as a filter layer, and the end of the drainage ditch is connected to the natural drainage channel.

9. A method for coordinated protection against multiple coupling damage in the grounding area of ​​a building / structure according to claim 1, characterized in that, For the protection of the grounding area of ​​newly constructed buildings / structures, the construction of the new buildings / structures must be completed before the foundation trench is excavated. Specifically, according to the design requirements of the new buildings / structures, the foundation pit is excavated and the pit treatment is completed. In the foundation pit that has been treated and qualified, the foundation pit and grounding area of ​​the new buildings / structures are poured in accordance with the design specifications. After the pouring is completed, the outer surface of the grounding area of ​​the newly constructed buildings / structures is sprayed with a protective layer that is the same as the outer surface of the grounding area of ​​the existing buildings / structures.

10. A method for coordinated protection against multiple coupling damage in the grounding area of ​​a building / structure according to claim 9, characterized in that, The construction of the foundation pit and grounding area of ​​the newly built / structured building is completed. After the construction is completed, the foundation pit and grounding area of ​​the newly built / structured building are cured. The curing time is determined according to the structure type. The curing time for concrete structures is not less than 7 days, and the curing time for masonry structures is not less than 3 days.

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